Table of Content Part I Turbine Mainframe Operation ................... ...................... ..................... .................... 4 Chapter I Overview and Specifications of Unit Equipment.................................................4 1. Overview of Steam Turbine and Auxiliaries....................................................................4 2. Main Design Specifications of the Unit ...................... ..................... ...................... .........8 .........8 2.1 Main Design Specifications of the Steam Turbine.................................................8 Turbine................................................. 8 2.2 Index of Steam Steam and Water Quality ..................... ...................... ..................... ......13 ......13 3. Main auxiliaries and system specifications..................................................................14 3.1 Feed water pump set..........................................................................................14 3.2 High and low-pressure bypass ................... ..................... ..................... .............. 22 3.3 Condenser..........................................................................................................26 3.4 Condensate pump ..................... ..................... ..................... ...................... ....... 27 3.5 Oil purifier .................... ..................... ..................... ..................... ...................... 29 3.6 Performance of water-ring vacuum pump unit....................................................31 Chapter II Protection, Control and Test Test of the Unit .................... ...................... ................ 32 1. General Rules of Interlock Protection Test...................................................................32 1.1 Purpose and Division Division of Interlock Protection Protection .................... ...................... ............ 32 1.2 Test Method of Interlock Protection .................... ..................... ...................... ..... 32 1.3 Verification for Interlock Protection Test Results.................................................32 2. Interlock Protection of Mainframe ...................... ...................... ..................... ............... 32 2.1 Main Thermal Protection of Steam Turbine ...................... ...................... ............ 32 3. Thermal Interlock Protection of Auxiliaries...................................................................43 4. Unit Control and Manual Devices .................... ...................... ..................... ................. 65 4.1 Sequence Control System (SCS) ..................... ...................... ...................... ...... 65 4.2 Analogue Control System (MCS)........................................................................66 4.3 Turbine Digital Electro-hydraulic Control System (DEH).....................................75 5. Main Test of the Unit....................................................................................................84 5.1 Static Test of the Control System........................................................................84 5.2 Manual Trip Test ...................... ...................... ..................... ...................... .......... 84 5.3 Trip Protection Test Test of Turbine Emergency Trip Trip System (ETS)... ........................ 85 5.4 Turbine Main Trip Solenoid Valve Test................................................................86 5.5 Power-load Unbalance Relay (PLU) Loop Test ....................... ....................... .... 87 5.6 Eccentric Ring Oil Spray Spray Test Test of Emergency Governor ..................... ................. 87 5.7 Emergency Governor Minimum Oil Spray Spray Action Speed Speed Test Test ..................... ........ 88 5.8 Turbine Mechanical Over-speed Test .................... ...................... ...................... . 89 5.9 Electric Over-speed Test of Steam Turbine ................... ..................... ................ 91 5.10 Valves Valves Activity Test .................... ..................... ..................... ...................... ....... 93 5.11 MSV and CV Leak Test.....................................................................................93
1
1
5.12 Mainframe Low Lube Oil Pressure Interlock Protection Test Test ..................... ....... 93 5.13 Vacuum Leakage Test ................... ..................... ..................... ..................... .... 94 5.14 Extraction Check Check Valve Valve Activity Test Test .................... ...................... ....................... 94 5.15 Load Rejection Test ..................... ...................... ...................... ..................... .... 94 Chapter III Start-up Start-up and Outage of the Unit and Operating Maintenance Thereof ........... 97 1 Start-up of the Unit........................................................................................................97 1.1 Start-up Specifications and Requirements..........................................................97 1.2 Start-up Prohibition Conditions of the Unit..........................................................98 1.3 Start-up Start-up State Classification of the Unit ..................... ....................... ................ 100 1.4 Inspection before the Steam Turbine Start-up ...................... ....................... ..... 100 1.5 Operation of Auxiliaries and Systems Systems before the Unit Start-up Start-up ..................... .... 101 1.6 Unit Start-up Parameters and Mode Selection Principal...................................103 1.7 Cold Start-up of the Unit ................... ...................... ..................... ..................... 104 1.8 Warm Warm and Hot Start-up Start-up of Unit............. ...................... ..................... .................. 115 1.9 Extreme Hot Start-up of Unit........................................................................... 1177 1177 2. Normal Operation and Maintenance of Unit............................................................. 1188 1188 2.1 Routine Maintenance and Requirements .................... ..................... ..............11 .............. 1188 88 2.2 Operational Parameters of Unit .................... ..................... ...................... .......11 ....... 1199 99 2.3 Adjustment Adjustment and Maintenance for Normal Operational Parameters of Unit Unit .....12 .....1222 22 3. Normal Shutdown of Unit...........................................................................................125 3.1 Preparations before Shutdown .................... ...................... ..................... .......... 125 3.2 Shutdown with Variable Parameter...................................................................125 3.3 Operations after Generator Disconnection .................... ....................... ............ 127 3.4 Cautions for Unit Shutdown............................................................................ Shutdown............................................................................12 1288 88 3.5 Regular work for steam turbine ...................... ...................... ..................... ....... 130 Chapter Ⅳ Accident Management of Unit..................................................................13 Unit.................................................................. 1333 33 1. General Principles .................... ...................... ...................... ..................... ..............13 ..............1333 33 2. Manual on the Handling of Unit Accidents............................................................... Accidents...............................................................13 1344 44 2.1 Emergency Outage Conditions of Unit ...................... ..................... ................13 ................1344 44 2.2 Fault Shutdown Conditions of Unit ..................... ..................... ...................... .1388 1388 2.3 Comprehensive Accident Management of Unit...............................................14 Unit............................................... 1400 00 3. Abnormal Operation and Accident Management of Steam Turbine.........................14 Turbine......................... 1466 66 3.1 Condenser Vacuum Drop ..................... ..................... ...................... ...............14 ...............1466 66 3.2 Steam Steam Turbine Water Attack .................... ..................... ..................... .............14 .............1488 88 3.3 Abnormal Vibration of Steam Steam Turbine Turbine ..................... ..................... ...................15 ...................1500 00 3.4 Increased Axial Displacement ..................... ..................... ...................... ........15 ........1522 22 3.5 Damaged or Broken Blade ................... ...................... ..................... ...............15 ...............1532 32 3.6 Lubricating Oil System Failure........................................................................ Failure........................................................................15 1533 33 2
3.7 EH Oil System Failure ................... ...................... ..................... ......................15 ...................... 1577 77 3.8 Feed Pump Failure.........................................................................................15 Failure......................................................................................... 1588 88 3.9 Deaerator Failure .................... ..................... ..................... ..................... ........16 ........1622 22 3.10 Heater Failure............................................................................................... Failure...............................................................................................16 1644 44 3.11 3.11 Generator Sealing Oil System Failure ..................... ...................... ...............16 ...............1655 55 3.12 Generator Hydrogen Cooling System Failure...............................................16 Failure............................................... 1677 77 3.13 Generator Stator Cooling Water System Failure............................................. Failure.............................................168 168 Part II Auxiliary System Operation ..................... ..................... ..................... ................17 ................1722 22 Chapter Ⅰ General Rules on Start-up (in operation) and Shutdown (out of service) of Auxiliaries and systems .................. ..................... .................... ..................... .................... ............17 ............1722 22 1. General Operating Rules of Auxiliaries....................................................................17 Auxiliaries.................................................................... 1722 22 2 General Outage Rules of Auxiliaries......................................................................... Auxiliaries.........................................................................17 1744 44 Chapter II Auxiliaries and Systems Systems ..................... ..................... ..................... ...............17 ...............1765 65 1. Lubricating Oil System.............................................................................................17 System............................................................................................. 1765 65 2. EH Oil System .................. ..................... ...................... ..................... ..................... ..17 ..1799 99 3. Unit Bypass System................................................................................................. System.................................................................................................18 1833 33 4. Gland Sealing System .................. ..................... ...................... ..................... ...........18 ...........1855 55 5. Vacuum System.........................................................................................................190 System......................................................................................................... 190 6. Circulating Water System ................... ..................... ...................... ..................... .....19 .....1933 33 7 Open Circulating Cooling Water System ...................... ....................... .....................19 ..................... 1955 55 8. Condensate System ................... ...................... ..................... ...................... ..............197 ..............197 9. Regeneration and extraction Steam System..............................................................200 10. Feed pump System ................... ..................... ..................... ..................... .............21 ............. 2111 11 11. Auxiliary Steam System ................... ...................... ...................... ..................... .....21 .....2199 99 12. Generator Sealing Oil System ..................... ...................... ...................... ..............22 ..............2222 22 13. Generator Hydrogen Cooling System....................................................................22 System.................................................................... 2244 44 14. Generator stator water cooling system .................... ..................... ...................... ... 229 Appendix ................... ..................... ..................... ..................... ..................... ............... 232
3
Part I Turbine Mainframe Operation O peration Chapter I Overview and Specifications of Unit Equipment 1. Overview of Steam Turbine Turbine and Auxiliaries The N600-16.7/538/538/-3 steam turbine used in this project is a subcritical, single reheat, condensing, tandem, three-cylinder four-exhaust, impulse steam turbine produced and designed by Dongfang Steam Turbine Works. The main and reheat steam of it is configured to unit system in form of two-one-two. Its high pressure (HP) cylinder contains one single-governing stage and eight-pressure stage; the intermediate pressure (IP) cylinder has five-pressure stage; the high and intermediate pressure (HIP) flow passages are designed to two-layer countercurrent with a common casing; and the low pressure (LP) is two-layer double-flow LP cylinder with 2*2*7 pressure stages. Through four pieces of admission pipe that are vertically and symmetrically arranged at the middle of the HIP outer casing, the main steam enters into the steam turbine, and then to the boiler reheater after experiencing HP 9-stage work. Similarly, the reheat steam enters into the IP part of the steam turbine in the same way as the main steam, and then enters into two LP two-pass cylinders separately through a piece of reducing connector after IP five-stage work; at last it is exhausted into a double-back pressure condenser through the bi-directionally arranged exhaust pipe of the two cylinders after the 7-stage work. The steam turbine is equipped with two HP main stop valves that are used for contacting the sealing surface well so as to prevent steam leak at the status of wide open. There are steam strainers inside the valves for purpose of preventing foreign substances from flowing into the flow passage. The unit is provided with four main steam control valves for regulating steam volume entering the steam turbine. They are equip ped with a balance chamber for preventing from vibrating and arranged into a shared valve casing in the form of straight line. The valve casing is independent of the steam turbine proper. The IP main steam valves and control valves are union valves with a common valve seat, wherein the former two are sleeve valves and the later four are spherical valves. Both of them are able to move independently during the total stroke, and opened, closed by hydraulic pressure and spring separately. The unit is also provided with two IP union valves each of which has a steam strainer for preventing foreign substances from entering the flow passage. Under normal condition, the IP main stop valves and control valves are widely open. The main stop valves, control valves and union valves are equipped with on-off testers solely used after overhaul and the remote test can be performed in operation of them on the condition that the load is not subject to large fluctuation. The structure of HIP cylinder with common casing and double-shell is used. It consists of four parts, including an integrated HIP outer casing divided into upper and low half casings from 4
the split, a HP inner casing divided into upper and lower half casings, an IP inner casing divided into upper and lower half casings and an IP outer casing. Two LP cylinders are symmetrical double split flow structure with the function of middle steam admission and divided into upper and lower parts from the split. The LP cylinders are designed to three-layer with the first layer served as inner casing for accommodating the elements of the flow passage, the second one as a heat insulating layer and the third one as an outer casing for exhausting steam and supporting the elements in the inner casing. The LP cylinder is connected with the condenser by a stainless steel elastic expansion joint. The shaft system of the unit is composed of a steam turbine HP rotor and IP rotor, LP rotor A and B and a generator rotor. Each of them is connected by a solid coupling. The steam turbine rotors without center holes are totally integral rotor. The steam turbine is supported by six pieces of bearing blocks; the HIP rotors are supported by two titling-pad bearings with #1 and #2 numbers of bearing block; two LP rotors are supported by two elliptical bearing with #3, #4, #5 and #6 numbers of bearing block, horizontal split and spherical types, and automatic alignment and manual manua l functions. A thrust bearing with the capability of withstanding much high axial thrust load, whereas resulting in little loss on any loads is structured to bevel dual thrust disc and located in a middle bearing housing beside the #2 bearing block. The expansion dead points of the HIP cylinder locates near the center line of the #2 bearing block, the LP cylinder A and B, respectively. A transverse pin at the dead point restricts the axial displacement of the cylinder, and longitudinal pins in front and back of the front bearing housing and the longitudinal center line of the two low pressure cylinders guide the cylinders to expand freely along the axial direction and restrict the deviation laterally. laterally. An automatic-meshing turning tu rning gear of the steam turbine consisting of a motor and gear train is equipped between the steam turbine and the generator. Its revolution is 1.5r/min and it is able to automatically operate and trip. To avoid water and steam from returning back the steam turbine, the drainage and exhaust steam systems of the steam turbine are designed to able to exhaust condensate in all of devices, pipelines and valves and steam in the HIP cylinder and HIP gland sealing system discharged at the time of unit trip. Their pneumatic drain valves are able to be automatically and widely opened at the time of lacking compressed air resource. To prevent steam from arriving at the intermediate and low pressure parts to do work through the steam sealing gland located between the high and intermediate pressure parts at the time of load rejection, an emergency discharge valve is set at the place of the steam sealing gland. In case that the IP control valve is closed, it automatically opens and reliefs most of leaked steam into the condenser. In order to avoid overheat at the HP steam exhaust part resulting from windage loss in case that the unit is started by the IP cylinder or high and low pressure bypass on low load, a vent valve (VV) is equipped on the exhaust pipeline of the HP cylinder to connect with 5
the condenser. There are no drain points on the high and intermediate pressure cylinders, and so water can be drained solely through the drain point on an extraction steam pipe. Water of the LP cylinder is drained to a condenser hot well level and water of the HP main steam pipes and valves is drained to a drain flash tank of the condenser. The unit is provided with two sets of rectangular drain flash tank located at lateral outer walls of the HP condenser and the LP condenser, respectively, and a spray de-superheating device that is used for spraying water while the unit is in operation. The regenerative system of the steam turbine has 8-stage non-regulatory extraction for three sets of HP heater, one deaerator and four sets of LP heater, respectively. respectively. Water of the HP and LP heaters reflows to the deaerator and the condenser, respectively by means of cascaded drain. Drain water can flow into the condenser directly in case of accident or low load. Steam source of the steam turbine for feed water pump is from four-stage extraction under normal conditions; in case of startup of the unit and low load, it is automatically switched to reheat steam. Its exhaust steam is discharged into a main main condenser. condenser.
Besides, for regenerative
extraction steam and steam of the steam turbine of the feed water pump, four-stage extraction of the steam turbine is able to provide auxiliary steam for others. To meet the demand of connecting the steam exhaust pipe and the drain pipe, the #7 and #8 LP heaters are designed to compound heaters with a common shell and horizontally configured at throat part of the condenser with part of which out of the shell. The condensate system employs an IP condensate polishing system each of which is provided with a vertical condensate pump with 2*100% volume and one of which is served as standby. Condensate after boosting pressure enters into the deaerator through a polishing unit, a gland heater and four LP heaters. The gland sealing system of the steam turbine is a self-sealing system, i.e. in normal operation of the unit, steam leakage from the shaft-end steam gland of the HIP cylinder, and the steam leakage from HIP main stop valve and valve stems of the control valves after being sprayed and de-superheated is provided for the LP shaft-end steam gland. The redundant steam flows to the LP heater or condenser through an overflow station. During startup or operation of unit on low load, the auxiliary steam station is used for providing steam for the steam gland. The unit is provided with one set of gland heater with 100% volume and two sets of gland extraction fan with 100% volume. The gland cooler and the steam turbine of the feed water pump shares the gland steam. During startup and operation of the unit with low load, gland steam is fresh or auxiliary steam and pressure of the gland main pipe is maintained by a gland steam supply valve and an overflow valve. During operation of the unit with 25%-60% of load, its gland steam is provided by the gland cooler; while the load is over 60%, the unit is self-sealed and the gland steam supply valve is closed. The set value of the gland pressure is maintained by the overflow valve and the redundant steam is discharged into #8 A LP heater through the overflow valve. The redundant steam is discharged into the condenser through a 6
conversion valve in case of #8 A LP heater failures. The emergency governing system is th e actuating mechanism of the t he HP fire-resistant oil DEH, which works on instruction reception from the DEH and completion of latching, meets the requirements of combined startup of high and intermediate pressure cylinders, startup of the IP cylinder and activity test of the valves, and has the functions of over-speed limitation, fast reliable steam admission interruption and over-speed protection. The system comprises a LP governing system and a HP fire-resistant oil system. The LP governing system is composed of an emergency governor, an emergency governor device and its link lever, a manual stop mechanism, a reset test valve block, a mechanical shutdown electromagnet and an oil guide ring, etc. Main functions of it comprise latch, interruption, oil spray and speed hoisting. The HP fire-resistant oil system consists of a hydraulic servo system, a HP trip system and a fire-resistant oil supply system. The hydraulic servo system, consisting of a valve control stage and a servomotor, is used for controlling opening of the valves and completing fast shutdown of them. This unit is provided with four sets o f servomotor for HP control valves, two for HP main stop valves, IP main stop valves and IP control valves, respectively. All of said servomotors, with unilateral oil feed, are started up by fire-resistant oil pressure and closed by spring force of the control stage, so as to guarantee all of them can be shut down in case of pressure
oil
loss.
The
oil
supply
system,
mainly
consisting
of
two
sets
of
pressure-compensated variable plunger pump, a regenerative device, an accumulator, oil filtering components, etc., is used for supplying HP working oil for every actuating mechanisms of the emergency governing system. The lubricating oil system is served as main oil pump-oil turbine system driven by the major axis of the steam turbine. In addition to all bearings of the turbine generators, it supplies oil for the hydrogen sealing system of the generators, the lubricating device of the turning gear and the jacking oil pump as well. It comprises a packaged oil container, a main oil pump (MOP), an AC auxiliary oil pump (TOP), a DC emergency oil pump (EOP), a boiler oil pump (BOP), a jacking oil device, an a n oil purification and regeneration device, six sets of electric heater, two sets of oil cooler with 100% volume, a change-over valve, a flume extractor e xtractor,, etc. The strainers in the lubricating oil system are able to be replaced to clean. In view from the head, the lubricating oil system locates on the right. For the purpose of successfully putting the turning gear into operation, the jacking oil system is applied to providing HP oil for every bearing at the time of startup and shutdown of the unit. Therefore, two sets of jacking oil pump, with the advantages of high efficiency, low heat value and noise, reliable performance and no leakage under continuous HP operation, and high volumetric efficiency, efficiency, etc., are applied in the system. The unit employs a HLP two-stage series-wound pneumatic bypass system, in which the capacity of high pressure bypass is 60%BMCR. This system is able to make the unit optimally start and shut down, realize two operating modes in accordance with the operating conditions, 7
startup and stop curves of the steam turbine, shorten the starting time of the unit in cooperation of setting up a steam temperature of the steam turbine suitable for the boiler’s. In case that the unit load is variable, the system can be applied to regulating it so as to improve the stability of the boiler in operation. The feed water system is configured to unit system, with two sets of 50% BMCR turbo-feed pump and one set of 50% BMCR electro-driven variable-speed feed water pump for one set of unit. The turbo-feed pump is put into normal operation and the electro-driven variable-speed feed water pump is served as standby or startup. The turbo-feed pump is provided with HP and LP steam sources and configured at the operating floor of the steam turbine, and its steam is exhausted into the condenser of the turbine mainframe. The feed water system also provides attemperating water for overheat and reheat attemperators, and the bypass system. The unit adopts a distributed control system (DCS) that has the functions of monitoring the DEH, MEH operator stations and other control systems (data communication interface) and meeting the requirements of various operating conditions. The DEH produced by Dongfang Electric Automatic Control Cooperation Limited for controlling the rotating speed and load of the steam turbine is employed in the turbine governing system. Startup mode of the unit: IP cylinder startup, combined startup of the HP, IP cylinders, whereas IP cylinder startup in priority. The combined startup mode is solely used in case that the bypass system is cut off due to failure. Operating mode
of
the unit:
constant
pressure, and constant
pressure-to-sliding
pressure-to-constant pressure Load character: with the main functions of bearing base load, and peak load manual function Arrangement of the unit: the turbine generating set is indoors longitudinal sequential arrangement. The lubricating oil system is configured on the right in view from the head to the generating set. Cooling mode of the unit: unit system with counter-flow circulating water system 2. Main Design Specifications of the Unit 2.1 Main Design Specifications of the Steam Turbine 2.1.1 Steam Turbine Proper Specifications
S/N
Item
Unit
Unit specifications
8
Data
S/N
1
Item
Unit
Unit model
Data
Sub-critical, single reheat, three-cylinder four-exhaust, tandem and condensing
2
Steam turbine model
N600-16.7/538/5 38-3
3
TMCR output
MW
600
4
VWO output
MW
640.647
5
HP
MW
600
MPa(a)
16.7
℃
538
heater
and
omni-segmentation
output 6
TMCR main steam pressure
7
TMCR main steam temperature
8
TMCR HP cylinder
exhaust
steam Mpa(a)
3.849
pressure 9
TMCR inlet pressure of reheat steam
Mpa(a)
3.464
10
TMCR inlet temperature of reheat steam
℃
538
11
TMCR main steam throttle flow
t/h
1876
12
Maximum throttle flow of main steam
t/h
2028
9
S/N
Item
Unit
13
TMCR throttle flow of reheat steam
14
TMCR exhaust steam pressure
15
Steam distribution mode
Data
t/h
1596.377
Mpa(a a(a)
0.01 .01013
Composite (nozzle/throttle)
16
℃
Design temp of cooling water
Open 32.4/closed 38
℃
277.2
Rated speed
R/Min
3000
TMCR heat consumption
kJ/kW.
8130/1942
17
TMCR feed temperature
18
19
h kcal/kW 20
Regene enerative heat grade ade of fee feed water
3+1+4 (high pressure plus de-oxidation plus low pressure)
21
Leng Length th of low low pres pressu sure re last last stag stage e blad blade e
mm
22
Total otal inte intern rnal al effi effici cien ency cy of stea steam m turb turbin ine e
%
High pressure cylinder efficiency
%
Intermediate
%
pressure
efficiency
10
cylinder
851 851
S/N
Item
Unit
Low pressure cylinder efficiency
23
Data
%
Series of flow passage
High pressure cylinder
Grade
9
Intermediate pressure cylinder
Grade
5
Low pressure cylinder
Grade
2*2*7
24
Critical speed
25
Shafting torsion frequency
Hz
26
Dime Dimens nsio ions ns (Len (Lengt gth, h, widt width h and and heig height ht))
m
27.8 27.82* 2*10 10.6 .68* 8*6. 6.29 29
2.1.2 Operational parameter
Item
Unit
Data
Full vacuum idle time
min
6
Idle time without vacuum
min
3
Max. load in case of main switch disconnection and
k
over-speed trip
W
Rotating speed of over-speed trip
r.p.m
640647 3330～ 3360(mechanical)33 00（electronic）
Max. Max. o eration erational al back back ressur ressure e
KPa a
18.6
Alarm back ressure of steam turbine
KPa a
19.7
KPa a
25.3
℃
12
Turbi Turbine ne tri back back ressur ressure e Max. allowable allowable o erational erational exhaust exhaust tem 11
℃
8
℃
12
S ra flow of LP c linder
t/h
4
Allowable min. continuous ratin
M
9
Allowable runtime under min. continuous rating
min
No limit
Max. Max. back back pres pressu surre at allo allow wable able min. in. cont contin inuo uous us rati ating
MPa( Pa(a)
0.01 0.0186 86
Max. Max. main ain stea steam m pres pressu sure re at allo allow wable able min. min. cont contin inuo uous us
MPa( Pa(a)
16.6 16.67 7
Max. main main steam tem at allowable allowable min. min. continuous continuous ratin ratin
℃
53
Alarm exhaust temp Exhaust Exhaust tem tem of manual manual shut shutdow down n
Vibration limit value of shaft relative to double amplitude of
μm
Not greater
vibration at rated revolution
than 34
Vibration limit value of shaft block relative to double amplitu
μm
Not greater
of vibration at over-critical revolution
than 80
Load limit at the time of stopping one set of LP heater
M
60
r. .m
1.5
Max. cylinder temp at turning gear shutdown
℃
15
Max. rotor temp at turning gear shutdown
℃
15
Revolu Revolutio tion n of turnin turnin
ear
Requirements for other short-term abnormal condition
-
2.1.3 Combined critical speed of every rotor in shaft system
First critical speed (r/min) Name
Shafting design Tandem design value
Second critical speed (r/min) Shafting design
value
Tandem design value
value
HIP rotor
17222
1621
Greater Greater than 4000 Greater Greater than 4000
LP rotor A
1839
1723
3521
LP rotor B
1903 1903
1750 1750
Greater Greater than 4000 Greate Greaterr than than 4000 4000
Generator
984 984
1070 1070
Grea Greate terr than than 3400 3400 3338 3338
rotor 12
Greater than 4000
2.1.4 Allowable load variation rate of the u nit
100％～50％MCR
Not less than 5％/min.
50％～30％MCR
Not less than 3％/min.
Less than 30％MCR
Not less than 2％/min.
2.2 Index of Steam and Water Quality
Item Item
Unit
Index
μs/cm
≤0.3
Sodium
μg/kg
≤10
Silicon dioxide
μg/kg
≤20
Iron
μg/kg
≤20
Copper
μg/kg
≤5
Electrical conductivity Steam
Remarks After hydrogen ion exchange at 25℃
Less than or equal to Hardness
μmol/L
≈0
5.0 when boiler startup
Silicon dioxide
Qualified
Less than or equal to 80 boiler startup Less than or equal to
Dissolved oxygen
μg/L
≤7
30 when boiler startup
Feed water
Less than or equal to Iron
μg/L
≤20
75 when boiler startup
Copper
μg/L
≤5
Hydrazine
μg/L
10～50
pH
9.0-9.5
Oil
mg/L
≤0.3
μs/cm
≤0.3
Hardness
μmol/L
0
Electrical
μS/cm
≤0.3
Electrical conductivity Condensate
conductivity
of
13
After hydrogen ion exchange at 25℃
Item Item
Unit
Index
μs/cm
≤0.3
Sodium
μg/kg
≤10
Silicon dioxide
μg/kg
≤20
Iron
μg/kg
≤20
Copper
μg/kg
≤5
Electrical conductivity Steam
Remarks After hydrogen ion exchange at 25℃
Less than or equal to Hardness
μmol/L
≈0
5.0 when boiler startup
hydrogen Dissolved oxygen
μg/L
≤30
Sodium
μg/L
≤10
3. Main auxiliaries and system specifications 3.1 Feed water pump set 3.1.1 General introduction There are two 50% BMCR-capacity steam-driven feed water pumps in each unit and one 50% BMCR-capacity electric feed water pump for start (standby). The steam-driven feed water pump is made up by the main feed water pump and its forepump providing a continuous water supply to the boiler and desuperheating water to the superheater, reheater of the boiler and the HP-bypass of the steam turbine. The electric feed water pump (including its forepump) is used when the unit starts, the main feed water pump is maintained or an accident occurs. When the main feed water pump set and the electric feed water pump set are operating in parallel, the characteristic curves of the two coordinate with each other within a certain speed adjustable range to enable the two pump sets run in parallel. If one set of the feed water pump fails, the electric feed water pump set can be put into operation within 30 seconds and achieve the required pressure, running with another main feed water pump set in parallel. 3.1.2 Equipment specifications 3.1.2.1 Technical Technical data of the main pump forepump
Operation condition
Item
Unit
Rating (efficiency point
Design rate
Maximum
Minimum
flow
flow
SQ300-670
Pump model
14
for
for
Water
inlet ℃
178.5
181.5
178.5
178.5
Water inlet pressure
MPa(g)
1.079
1.12
1.079
1.079
Flow
3 m /h
1104.8
1347.4
1500
305
Pump delivery
m
135
131
130
144.9
Efficiency
%
84
84
82
39
NPSH required
m
2.9
4.6
6
1.6
Seal form
mechanical seal
Speed
r/min
1485
1485
1485
1485
Outlet pressure
MPa(g)
2.26
2. 2.26
2.21
2. 2.34
Shaft power
kW
429.6
506.5
575.4
274.2
Weight
kg
1598
Interface
inlet
MPa(g)
4.0
flange
outlet
MPa(g)
4.0
Specifications inlet
mm
DN400
of
mm
DN350
the outlet
interface pipe Rotation direction
clockwise (C.W.)(from the drive end to the pump)
Bearing type
inlet rolling bearing
Drive mode
electric motor
Note: (g) refers to gauge pressure in the table
3.1.2.2 Technical data of the main feed water pump
Operation condition
Item
Unit
Rating (efficiency point
Design rate
Minimum
flow
flow
for
CHTC6/5
pump model Water
Maximum
inlet ℃
178.5
181.5
178.5
178.5
tem tem erat eratur ure e Water inlet density
3 kg/m
887.9
884.6
887.9
887.9
Water inlet pressure
MPa(g)
2.15
2.15
2.08
2.21
Water inlet flow
3 m /h
1104.8
1347.4
1350
270
15
for
Water outlet flow
3 m /h
Pump delivery
1056.4
1298.8
1350
270
m
2111 2111
2248
1820
2550
Efficiency
%
82.5
83
81
36
NPSH required
m
34
43
40
22
Seal form
inlet Burgmann mechanical seal
Speed
r/min
4673
5008
4678
4678
Outlet pressure
MPa(g)
20.519
21.64
17.93
24.42
Shaft power
kW
6626.5
8609.7
7339
4627.4
Tap pressure
MPa(g)
9.34
9.96
－
－
Tap flow
3 m /h
48.5
48.6
－
－
Supercharging
MPa(g)
no supercharging
Supercharging flow
m3/h
no supercharging
Shaft vibration
mm
Weight
kg
Rotation direction
0.03
0.03
0.03
0.03
7220 clockwise (C.W.)(from (C.W.)(from the feed water turbine to the feed water
Bearing type
Rolling bearing+ Kingsbury-type thrust bearing
Drive mode
turbine
3.1.2.3 Technical Technical data of the electric pump forepump
Operation condition
Item
Unit
Rating (efficiency point
Maximum Design rate
fo
flow
SQ300-670
Pump model Water
flow
Minimum
inlet ℃
178.5
181.5
178.5
178.5
temperature Water inlet pressure
MPa(g)
1.079
1.12
1.079
1.079
Flow
3 m /h
1104.8
1347.4
1500
305
Pump delivery
m
135
131
130
144.9
Efficiency
%
84
84
82
39
NPSH required
m
2.9 2 .9
4.6
6
1.6
Seal form
Mechanical seal 16
for
Speed
r/min
1485
1485
1485
1485
Outlet pressure
MPa(g)
2.26
2.26
2.21
2.34
Shaft power
kW
429.6
506.5
575.4
274.2
Rotation direction
clockwise (C.W.)(from the drive end to the
Bearing type
Inlet trolling bearing
Drive mode
electric motor (driven by the same axle with
3.1.2.4 Technical Technical data of the electric feed water pump Operation condition
Item
Unit
Rating (efficiency point point
Design rate
Minimum
flow
flow
for
inlet ℃
178.5
181.5
178.5
178.5
Water inlet density
3 kg/m
887.9
884.6
887.9
887.9
Water inlet pressure
MPa(g)
2.15
2.15
2.08
2.21
Water inlet flow
m3/h
1104.8
1347.4
1350
270
Water outlet flow
3 m /h
1056.4
1298.8
1350
270
Pump delivery
m
2111 2111
2248
1820
2550
Efficiency
%
82.6
83
81
36
NPSH required
m
34
43
40
22
Seal form
Inlet Burgmann mechanical seal
Speed
r/min
4673
5008
4678
4678
Outlet pressure
MPa(g)
20.519
21.64
17.93
24.42
Shaft power
kW
6626.5
8609.7
7339
4627.4
Tap pressure
MPa(g)
9.34
9.96
－
－
Tap flow
m3/h
48.5
48.6
－
－
Shaft vibration
mm
0.03
0.03
0.03
0.03
Rotation direction
clockwise (C.W.)(from the feed water pump turbine to the feed water pump)
Bearing type
for
CHTC6/5
Pump model Water
Maximum
Rolling bearing+ Kingsbury-type thrust bearing
17
Drive mode
turbine
3.1.2.5 Electric motor parameter Equipment Item
Unit
Motor of the forepum
Motor of the electric
of the main feed wate
feed water pump
Rated power
kW
560
10050
Rated voltage
kV
6.6
11
Synchronous speed.
r/min
1500
1500
Frequency
Hz
50
50
Rotation direction
Anticlockwise (fro m the Anticlockwise
(from
the
forepump to the motor) forepump to the motor)
3.2 High and low-pressure bypass 3.2.1 General Introduction Every unit is equipped with a B-MCR high-pressure bypass with 60% capacity and two low-pressure bypasses whose capacity is coordinate with the high-pressure bypass. The actuator is hydraulic. Bypass device can improve the start-up facility of the unit. When the unit starts in a variety of operating conditions (cold, warm state, hot and very hot), we can use th e bypass system to control the temperature of the boiler steam to make the temperature of the steam match with that of the metal of the cylinder in short period of time, thus to reduce the time for the unit to start, the quantity of the steam as well as loss of steam turbine cycle life to achieve the best performance of start-up. When the unit operates normally, the high-pressure bypass device has over-pressure safety protection features. Once the pressure of main steam exceeds the setted value of the high-pressure bypass, the valve of the high-pressure bypass will open quickly to reduce the take off of PCV valve and safety valve and automatically adjust the pressure of the main stream till it returns to be normal. Low-pressure bypass device should have the function of reheater overpressure protection and condenser protection. Bypass can run in two ways: constant pressure matching appropriate unit operation and sliding pressure operation. The bypass installation can work together with the unit to achieve the role of regulation. When the power grid or the unit appears load rejection because of the fault trip, the bypass device will operate quickly to maintain the minimum load operation function of the boiler by using belting factory electricity, idling or shutdown thus the unit can be ready to re-grid to resume normal operation. Reducing the load while starting up and load rejection can prevent the reheater setting in the area with higher gas temperature from burning out. High pressure and low pressure bypass device are in the hot 18
standby state under normal conditions. The water which High temperature bypass uses to reduce the temperature comes from the high-pressure water; the water of low pressure bypass comes from the condensing water. This machine consists of high-pressure bypass (main steam) and low-pressure bypass (re-heat steam) two series bypass system devices. High-pressure bypass system device consists of high-pressure bypass valve (high side valve), water-jet control valve and water isolating valve etc. Low pressure bypass system device consists of low-pressure bypass valve (low side valve), water-jet control valve and water isolating valve etc. Water temperature control valve and reducing isolating valve are both hydraulic enforcement agency. HP bypass and LP bypass are both with the same pattern. The fuel supply device (petrol station) of the Bypass system’s hydraulic actuator allocated one set (high pressure bypass and low pressure bypass share a set). The time of automatically using petrol station is 1 second, after 60 seconds, the working hydraulic can be achieved. There is storage accumulator of petrol station to store energy, in case of power failure; it can still provide sufficient hydraulic power to all system valves of the bypass b ypass to complete two-time All-trip on or off. Petrol station sets up with one accumulator and high-pressure bypass device sets up a separate accumulator as well. The working media of the Hydraulic actuator is anti-burning oil. Oil system consists of two parts of pressure oil:
16MPa control-oil and 13.5MPa pilot oil.
3.2.2 Technical Technical Parameter of the Equipment Parameter table of the turbine bypass of medium-pressure tank tank
start-up (IP) operation
condition Stop Startin Name of the Technical Technical Parameter
Unit
Starting
Starting
up
up
in
in
the
Designe
up machin d
Starting
g
up in hot
in
e
state
very
without n
hot
stoppin
conditio
cold
warm
state
state
MPa(a)
6
8.62
8.62
12.9
8.77
℃
390
420
440
510
541
Steam High Pressure
Pressure of
17.5
the Entry
Steam Transformin g Valve
Steam Temperatur e
of
the
Entry
19
541
Steam Flow
of
t/h
240
240
320
320
608.4
1216.8
MPa(a)
～1.3
～1.3
～1.3
～1.3
～1.2
4.1
℃
~200
~235
~255
~330
291.4
358．11 35086 86 ．
717． 9
the Entry
Steam Pressure of
the
Exit
Steam Temperat ure of the
33 5
Exit
Steam Flow
of
t/h
275．42
26849 49 ．
1399．2
the Exit
Pressure
MPa(a)
~10
~12
~12
~16.5
~12
2 2
Temperat
High Pressure
℃
ure
110
110
110
110
110
185
35．42
28．49
38．11
30．86
109． 5
182．48
1.1
1.1
1.1
1.1
1.19
3.7
Water-jet Control
Flow
t/h
Valve
Low
Pressure
Steam
Steam
Pressure
Transforming
of
Valve
Entry
the
MPa(a)
20
Steam Temperat ure of the
℃
340
400
420
480
540
540
Entry
Steam Flow
of
the Entry
358． t/h
138
134
179
175
95
MPa(a)
0.6
0.6
0.6
0.6
0.6
℃
160
160
160
160
160
70 0
Steam Pressure of
the
0.6
Exit
Steam Temperat ure of the
16 0
Exit
Steam Flow
of
t/h
158．29
． 16037 37
217．2
． 2211 1
the Exit
Low Pressure
471． 65
913．07
Pressure
MPa(a)
3.3
3.3
3.3
3.3
3.3
3.3
Temperat
℃
46.3
46.3
46.3
46.3
46.3
46.3
20．29
26．37
38．2
46．11
112． 7
213．07
Water-jet Control Valve
Flow
t/h
21
3.2 High and Low Pressure Heater and Deaerator 3.2.1 General introduction The heat extraction system of the unit consists of 3 high-pressure heaters, 4 low-pressure heaters and 1 deae rator. rator. High-pressure feed-water heaters are horizontal heat exchanger with surface condenser which consists of drain cooler, condenser and steam cooler. The shell of high-pressure feed-water heater is with all welded structure. At the side of the heater installs the pressure relief valve to prevent the shell from damaging while the pipe is damaged. Water side also equips with pressure relief valve to prevent the heater from overpressure due to heat expansion when the heater’s inlet valve and outlet valve is closed and the side has extraction stream. High-pressure feed-water heaters equips with normal drain and emergent drain as well as related accessories. During the process of starting up and continuous operation of the unit, in order to remove the non-condensing gas gathered in the steam dead zone, there is enough vent connection and internal baffle equipped in the heater whose displacement is designed according to 0.5 % of the steam into the heater. The drain cooler of the heater has sufficient depth to ensure water seal is not damaged when the water level reaches minimum. When high-pressure heater is put into operation, it can meet the requirement of the speed to unit load as well as meet meet the water temperature temperature change rate reaches reaches 3 ℃ / min min while while loading up and 2 ℃ / min while loading down without affecting the safety and duration of the heater. Low-pressure heaters are horizontal all welded which can withstand the change of full vacuum, extraction pressure, the reaction of connected pipeline and thermal stress. When the adjacent heater failure is removed, the water heater can adapt to the increase of the gas-side flow and operate continuously. At the side of the tuber of the heater and shell separately sets up with pressure relief valve, (delete, )加 and the shell-side pressure relief valve (No. 7,8 don’t equip with pressure relief valve) to ensure the safety of the shell when the tube is damaged. The material of the bundle of heater is stainless steel. When the steam turbine trip, to prevent excessive flash steam come into the steam turbine, the No. 7, 8 (part of exhaust device) equips with stainless steel anti-flash baffles .To prevent the bundle from shocking, vibrating and scouring, in the inner side of steam trap inlet connection equips with stainless steel anti-shock plate. All low-pressure feed-water heaters equips with normal drain and emergent drain. Normal drain connects with drain cooler while emergent drain connects with condenser. Deaerator is horizontal and inner setting. It is installed in the 24m layer, B-C column of the steam room. The deaerator operation mode is constant pressure - sliding pressure - constant pressure. Deaerator has 3 low-pressure water pipe interfaces. The diameter of each pipe is designed according to 50% of the largest water flow. The water tank of the inner setting deaerator equips with overflow electric valve to maintain the water level of the tank
3.2.2 Equipment parameter 3.2.2.1 Design parameter of the high-pressure heater 22
Heater No.
Unit
1#
2#
horizontal type，U-tube
1 Heater model 2 Heater quantity 3
Bypass
3#
type
1 of
high-pressure
1
1
small
heater(large、small bypass)
bypass
I Operation condition of adjusting valve wide open (VWO) of the steam turbine Feed water 1 Flow 2 Inlet pressure 3 Inlet temperature 4 Inlet enthalpy
t/h
2028
2028
2028
MPa(a)
/
/
/
℃
250.5
219.3
185.2
kJ/kg
1088.5
946.1
795.6
℃
282.3
250.5
219.3
5
Outlet temperature
6
Outlet enthalpy
kJ/kg
1242.6
1088.6
946.1
7
Maximum allowable pressure drop
MPa
＜0.1
＜0.1
＜0.1
8
Maximum allowable flow rate
m/s
≤3
≤3
≤3
9
Design pressure (interim)
MPa(g)
28
28
28
℃
310
280
250
10 Design temperature 11 Test pressure press ure
Refer to ASMEⅧ-Ⅰ
MPa(g)
Steam extraction 12 Flow
t/h
152.166
127.47
101.295
MPa(a)
6.672
4.133
2. 2.36
℃
400.6
335.1
469.6
15 Inlet enthalpy
kJ/kg
3169.2
3053.8
3396.2
16 Maximum allowable pressure drop
MPa
≤0.07
≤0.07
≤0.07
MPa(g)
7.3
4.65
2.5
℃
415/290
355/260
485/230
13 Inlet pressure 14 Inlet temperature
17 Design pressure 18 Design temperature 19 Test pressure
Refer to ASMEⅧ-Ⅰ
MPa(g)
Drainage entering in the heater 20 Source of the Drainage
/
1#
2#
21 Flow
t/h
/
152.164
279.634
22 Temperature
℃
/
256.1
224.9
kJ/kg
/
1115.4
966.3
23 Enthalpy Drainage drained from the heater
23
Heater No.
Unit
1#
2#
3#
24
Flow
t/h
152.164
279.634
380.93
25
Temperature
℃
256.1
224.9
190.8
26
Enthalpy
KJ/kg
1115.4
966.3
811 811
27
Drain approach
℃
≤5.6
≤5.6
≤5.6
II Operation condition of turbine maximum continuous output (T-MCR) (T-MCR) Feed water 1
Flow
2
Inlet pressure
3
Inlet temperature
4
Inlet enthalpy
5
Outlet temperature
6
Outlet enthalpy
t/h
1876
1876
1876
MPa
/
/
/
℃
246.3
215.7
182.1
kJ/kg
1068.9
929.9
782.3
℃
277.2
246.3
215.7
kJ/kg
1217.5
1068.9
929.9
135.3
115.215
91.82
MPa
6.183
3.849
2.2
℃
391.7
327.7
469.9
kJ/kg
3155.2
3042.1
3398.9
Steam extraction 7
Flow
8
Inlet pressure
9
Inlet temperature
t/h
10 Inlet enthalpy Drainage entering in the heater 11 Source of the Drainage
/
1#
2#
12 Flow
t/h
/
135.3
250.516
13 Temperature
℃
/
251.9
221.3
kJ/kg
/
1094.8
949.4
15 Flow
t/h
135.3
250.516
342.345
16 Temperature
℃
251.9
221.3
187.7
KJ/kg
1094.8
949.4
797.4
14 Enthalpy Drainage drained from the heater
17 Enthalpy
3.2.2.2 Design parameter of low-pressure heater (T-MCR operation condition) 5# Heater No.
6#
7#
8#
2
2
Unit
1、Heater model
U-tube、horizontal type
2、Heater quantity
1
Condensate 24
1
1 、Flow Flow
t/h
1434.49 1434.493 3
2 、Inlet pressure (working pressure, MPa(a) 4
1434.49 1434.493 3 1434.49 1434.493 3
1434.49 1434.493 3
4
4
4
interim) 3 、Inlet temperature
℃
118.8
100.8
83.6
47
4 、Inlet enthalpy
KJ/Kg
500.7
424.7
352.6
199.4
5 、Outlet temperature
℃
137.4
118.8
100.8
83.6
6 、Outlet enthalpy
KJ/Kg
579.6
500.7
424.7
352.6
7、 Flow
t/h
46.546
44.003
41.067
79.658
8 、Inlet Inlet pressu pressure re
MPa(a) MPa(a) 0.382 0.382
0.22
0.121 0.121
0.06 0.064 4
9 、Inlet temperature
℃
245.3
186.6
129.1
87.8
10、Inlet enthalpy
KJ/Kg
2955.4
2842.2
2732.8
2631.8
11、Flow
t/h
0
46.547
90.550
131.616
12、Temperature
℃
0
124.4
106.4
89.2
13、Enthalpy
KJ/Kg
0
522.7
446.2
373.7
14、Flow
t/h
46.547
90.550
131.616
213.836
15、Temperature
℃
124.4
106.4
89.2
52.6
16、Enthalpy
KJ/Kg
522.7
446.2
373.7
220.2
Steam extraction
Drainage entering in the heater
Drainage drained from the heater
3.2.2.3 Design parameter of deaerator Item
Built-in deaerator
Type
Built-in horizontal type
Model YC-1876 Shell material SA-516 Gr.70 Head material SA-516 Gr.70 Design pressure（MPa.g） 1.27/-0.1 Design temperature℃
steam connection：371/bulk: 250
Diameter / length / thicknessmm ~3860/28300/30 25
Total
height
after
installation
(including ~5700
supports)mm Weld joint factor
1 vessel head ：0.25/connection pipe：0.15
Corrosion allowance cm Weight (net)kg
107300 Full water weight kg 469000 Operating weight kg 350900 3.3 Condenser 3.3.1 General introduction The condenser is with double shells, single process and double-pressure surface. It is with side by side horizontal layout. The condenser is with all welded steel structure which includes two oblique throats, two shells (hot well, water room and reheating pipe system), recycled water connecting pipe and fixed bearing. The condenser not only accepts the drain of the host, jack-engine and ontology, but also accepts that of low pressure bypass, high-pressure and low-pressure accident as well as that of deaerator overflow. The throat part of the condenser equips with No. 7, 8 low pressure heater, water-feed pump turbine as well as triple desuperheating station at the side of Bypass system of steam turbine. When the condensed water, drained water and supplementary water come into the condenser, they can be effectively heated and sprinkled to achieve the best effect of deaerating. The condenser can be hemi-run, under this condition, the steam turbine can reach 60% of the rated power. 3.2.2 Parameter of the condenser No.
Item
1
The total valid area of the condenser
2
The drained valid area
3
Flow number/shell number
4
Net heat brought away by circulating
Unit 2 m 2 m
Data 30500 1830 1/2
kJ/s
795300.3
water of VWO operation condition 2 W/m .℃
5
Heat transfer coefficient
3234.4/3303.3
6
Circul Circulati atin n water water flow flow
t/h
71500
7
Maximum flow rate of circulating water in
m/s
2.3
8
Design flow rate of the cooling tube
m/s
2.3
9
Clean Cleanin in coef coeffi fici cien entt
0.85 26
10
Increase Increase of the the circulati circulatin n
water of VWO
℃
10.2
11
The degree of supercooling of condensate
℃
0.5
12
Desi Desi n termi termina nall tem eratu erature re diff differ erenc ence e of
℃
13
Desi n re ressure of water chamber
MPa.
0.4
14
Desi n re ressure of shell side
MPa.
Vac.—0.15
15
Oxygen
g/l
30
16
Total water resistance of tube
kPa
61
17
Condenser steam resistance
kPa
0.1
18
Circulating
19
Weight of water chamber(each)
kg
20
Net wei ht ht of the condenser
k
750000
21
Condenser wei ht o er eratin
k
1350000
22
Condenser wei ht ht full water
k
2550000
23
Test pressure of water chamber
content
ratio
required
(design
of
the
6.02/5.85
operation
55 15000
1.5 times of the design pressure
3.4 Condensate pump 3.4.1 General introduction of condensate pump Transfer the condensate in the turbine condenser to the deaerator, and provide the turbine low-pressure bypass and desuperheater with desuperheating water and other things. Each unit is equipped with two condensate pumps, one for work and the other for standby. The condensate pumps are vertical and vessel type multistage centrifugal pumps with 4-stage impeller. The condensate pump is constituted by shell, outlet connection pipe, pump spindle, 4-stage impeller, coupling, sealing element, pump base, etc. 3.4.2 Operating parameter of the condensate pump Mode of pump NLT500-570X4S Pump operation condition
Nameplate
point Item
operation Rating
condition
operatio
condition（TMCR ） (efficiency
Unit
required) Water
℃
inlet
temperature Water pressure
46.3
46.3
0.01
0.01
inlet M P 27
point
a a Flow t
1693
1434.493
/ h Total
outlet M
pressure
3.25
3.41
M
333
350
%
83.6
83
5.2
5
1480
1480
p a a Pump lift efficiency
NPSH m H 2
O Speed r / m i n Shaft
K
power
w
1835.8
1646.7
M
3.25
3.41
Total outlet pressure
P a inlet/outlet
nominal mm/mm
diameter inlet/outlet pressure
800/500
800/500
nominal M
1.6/5.0 28
1.6/5.0
P a g Design
pressure
of MPa(g)
pump Rotation direction
5
5
Anticlockwise (from the motor to the condensate pum)
3.5 Oil purifier Each unit is equipped with an oil purifier, which is able to purify the steam turbine lubricating oil while on-line or shutdown, to remove impurities particles, moisture, break emulsification, so that the main steam turbine or feed water pump would drive the small steam turbine lubricating oil to be reborn. No.
Item Manufacturer
1
2
Unit
Manufacturing
4
－
Data Made by Alfa Laval, Sweden Assembled by Beijing Touping New Technology Development
－
M
－
Type
－
Made by Alfa Laval, Sweden, assembled in Beijing MAB206 Offcenter pattern
Purification devices rated 5
L/h
output
6
Suitable oil
－
7
Filtration
μm
10600 32、46 or 68 ≤3
moistu 8
The quality of treated oil
≤33PPm
particle
NAS standard 7 or Morgan 6
count 9
Oil-providing pump model
10 Oil-providing pump type 11
Oil-providing
－
KFUG42
－
horizontal type gear pump
pump m3/h
13
12 Oil-providing pump delivery M a
0.15
13 Shaft power of oil-providing KW
11
14 oil-providing pump speed
r/min
1500 29
15 16 17
Motor
model
of
－
Made by ABB company, provided by Alfa Laval, Sweden
oil-providing Rated
power
of
Rated
voltage
of
18 Speed
of
KW
12
V
415
oil-providing r/min
1500
19 Centrifuge model
－
MAB206
20 Centrifuge type
－
vertical type
21 Centrifuge capacity
3 m /h
22 Centrifuge shaft power
KW
23 Centrifuge speed
r/min
24 Centrifuge motor model
－
25 Rated power of centrifuge 26
Rated power of centrifuge
10.6 11 8425 Share the same motor with oil-providing pump K
12
V
415
27 Centrifuge motor speed
r/min
1500
28 Maximum noise level
dB(A)
85
Equipment dimensions 29
Mm
(length, width, height) oil inlet oil outlet The interface
30
drain outlet
size
water sealed 31 The
interface
32 Net
weight
33 Weight 34 Maximum
Mm
DN40
Mm
DN40
Mm
DN20 1/2 inch internal thread
Mm
pressur e M a of
of
1800×1400×1300
16
the K
1000
running Kg
1020
maintenance Kg
1020
35 Material of centrifuge oil pum －
cast steel
－
cast steel
－
stainless steel
－
stainless steel
36 Material of centrifuge oil pump lid 37 38
Material of centrifuge oil pum im eller Material of centrifuge oil pum
39 Power of electric heater
KW
96 30
Oil purifier specifications 3.6 Performance of water-ring vacuum pump unit: (1) Minimum suction pressure (ultimate vacuum) of the water-ring vacuum pu mp: 2900 Pa(a) (2) Pump speed: 490r/min (3) Impeller nominal diameter: 76.5cm (4) Speed: 19.62m/s (5) Shaft power: (maximum) 150 kW
(minimum): 94kW Shaft power: 10.13kPa: 113KW;
11.8kPa: 117KW (6) Starting power: 94KW (7) Pumping capacity≥100 kg/h (inlet pressure is 10.13kPa and cooling water temperature is 32.5℃) (8) Electric motor model: Y450S-12 motor protection level: IP54
rated power: 185 KW
motor insulation level: F
speed: 490r/min
voltage: 415V，
motor temperature rise: B
(9) The cooling water amount of pump heat exchanger: 40m3/h, water quality: seawater, water temp temper eratu ature re:: 32.5 32.5℃, sepa separa rato torr make make-up water water flow: flow:<0. <0.5m3 5m3/h, /h, tempe temperat rature ure:: 50℃ . The tubin tubing g heat exchanger is made of titanium tube, the heat exchange area: S=25 m2, the working pressure of cooling water: 0.34 MPa(g), the design pressure of cooling water: 0.6 MPa(g), the design temperature temperature of cooling cooling water water inlet: inlet: maximum maximum 33 33℃ , the amount amount of cooling cooling water: water: 90 m3/h, workin working g amount amount:: 20.4m3 20.4m3/h, /h, the the tempe temperat rature ure of of workin working g water water inle inlet: t: 36.6 36.6℃ , the outlet outlet temp tempera eratur ture: e: 47.7 47.7℃ , terminal terminal temperatur temperature e difference: difference:4 4℃ , side voltage voltage drop of coolin cooling g water: water: <0.05Mpa <0.05Mpa
31
Chapter II Protection, Control and Test of the Unit 1. General Rules of Interlock Protection Test 1.1 Purpose and Division of Interlock Protection 1.1.1 Test purposes: check thermal interlock protection circuit action for correctness, including the action of primary single circuit and interlock protection. 1.1.2 Division of test 1.1.2.1 Inspection associated with thermal device, and thermal technicians in responsible of forcing, stimulating and resetting of thermal single 1.1.3.2 Field apparatus inspection associated with the test, and operators in responsible of the operation of the electric switches and OPR 1.2 Test Test Method of Interlock Protection 1.2.1 Single imitation 1.2.2 Transmission test 1.3 Verification for Interlock Protection Test Test Results 1.3.1 Hard wired circuit test 1.3.2 Interlock protection test 1.3.2.1 Mainframe protection test (see thermal protection of the mainframe) 1.3.2.2 Auxiliary protection test 2. Interlock Protection of Mainframe 2.1 Main Thermal Protection of o f Steam Turbine
2.1.1 Turbine DEH and ETS trip protection ETS over-speed protection TST over-speed protection DEH over-speed protection High metal temperature (left and right) protection for inner walls of the HP cylinder exhaust 1. Send an alarm signal of high metal temperature in case that th e metal temperature of the HP cylinder’s exhaust is greater than or equal to 420 degrees centigrade. 2. Shut down by the action of protection in case that the metal temperature of the HP cylinder’s exhaust is greater than or equal to 432 degrees centigrade. 32
High metal temperature (back and right) protection for LP cylinder exhaust 3. Send an alarm signal of high metal temperature in case that th e metal temperature of the LP cylinder‘s exhaust is greater than or equal to 80 degrees centigrade. 4. Shut down by the action of protection in case that the metal temperature of the LP cylinder’s exhaust is greater than or equal to 107 degrees centigrade. Low vacuum protection of condenser: Shut down by the action of protection in case of low vacuum of conden ser. ser. Low lube oil pressure protection: 5. Send an alarm signal of low lube oil pressure in case that the lube oil pressure is less than 0.1 0. 115MPa; 6. Shut down by the action of protection in case that the lube oil pressure is less than 0.069MPa; Shut down by the action of projection in case of low EH oil pressure (one of two logic) (1, 3 and/or 2, 4). Large vibration protection of bearings Send an alarm signal of large vibration in case that the vibration of any bearing is greater than or equal to 125um; Shut down by the action of protection in case that the vibration is greater than or equal to 250um. 1. Send an alarm signal of large axial displacement in case that the axial displacement of the steam turbine is less than negative 1.05mm or greater than positive 0.6mm. 2. Shut down by the action of protection in case that the axial displacement of the steam turbine is less than negative 1.65mm or greater than positive 1.2 mm. Differential expansion protection of HIP cylinders 1. Send alarm signal of large differential expansion in case that the differential expansion is less than negative 5.3mm or greater than positive 10.3mm; 2. Shut down by the action of protection in case that the differential expansion is less than negative 6.6mm or greater than positive 11.6mm. Differential expansion protection of LP cylinder 1. Send alarm signal of large differential expansion in case that the differential expansion is less than negative 4.6mm or greater than positive 19.8mm; 2. Shut down by the action of protection in case that the differential expansion is less than negative 8mm or greater than positive 30mm. DEH electricity loss protection Generator protection Malfunction of a trip protection button on the console Trip by the action of protection in case that temperature of any bearing shell of #1-#8 journal bearings is high (5 (5 seconds delay) (alarm when temperature of #1-#6 bearing shells reaches 110 degrees centigrade and trip when reaching 115 degrees centigrade; 33
meanwhile, alarm and trip temperatures of the #7 and #8 bearing shells are 110 and 115 degrees centigrade, respectively); Trip by the action of protection in case that the temperatures of #1-#8 working thrust pads are high (time delay 5s) (alarm and trip temperatures of them are 85 and 110 degrees centigrade, respectively); Trip by the action of protection in case that the temperatures of #1-#8 locating thrust pads are high (time delay 5s) (alarm and trip temperatures of them are 85 and 110 degrees centigrade, respectively); Shut down by the action of protection in case that the steam temperature of the main stop valve at the inlet is LL (low, low); Shut down by the action of protection in case that cooling water inlet flow of the generator stator is LL; Shut down by the action of protection in case that inlet cooling water pressure of the generator stator is LL; Shut down by the action of protection in case that outlet cooling water temperature of the generator stator is HH (high, high). 2.1.2 Over-speed protection 2.1.2.1 Over-speed protection control system (OPC): the momentary speed of the steam turbine will reach maximum in case that the trip signal of the generator main switch does not send out due to control single lag and residual steam at the time of load rejection of the unit. In order to prevent the unit from tripping for a rotating speed capable of causing tripping, the HIP control valve must be closed fast and immediately to prevent speed rise when the rotating speed reaches 103% of the rated. 2.1.2.2 When the rotating speed of the steam turbine reaches 110%-111% of the rated speed, the eccentric ring mechanical emergency governor drives the mechanical trip valve into action to drain the oil in the emergency trip system (ETS), to close the high pressure main stop valve and the high pressure control valve and to open the vent valve. And then the steam turbine is stopped after closing the intermediate pressure main stop and control valves, the extraction check valves and exhaust check valve of the HP cylinder at all levels and opening the dump valve. 2.1.2.3 Electric over-speed protection: immediately close the HIP MSV and CV to stop feeding steam while the rotating speed of the unit reaches 111% of the rated speed; meanwhile, the DEH sends out a stop signal. 2.1.3 Manual shutdown 2.1.3.1 Manual field tripper: it is set at the front box of the steam turbine. While operating, the tripper is first drawn out after counter-clockwise rotating 90°, and then the HP MSV and HP CV, IP MSV and IP CV, the exhaust check valve of the HP cylinder and check valves at all level are closed and the vent valve is opened after the safety oil is drained by the action of the mechanical trip valve. 34
2.1.3.2 Manual remote tripper: it is of double-button and equipped on the control desk of the central control room. Pressing the buttons will bring the mechanical solenoid and the main trip solenoid A and B into action to close HP MSV and HP CV, IP MSV and IP CV, the exhaust check valve of the HP cylinder and check valves at all level and open the vent valve. 2.1.4 Protection system for preventing water induction Principal for classification of water induction-preventing control Divide the turbine steam source piping, steam turbine proper and drain valves of every extraction piping into HP, IP, LP drain valves; Exclude every extraction check valves for the reason that the said valves are totally used for preventing water into steam turbine; Open and close the said three valves in accordance with the load level, they are divided into 10%, 20% and 30% MCR; Set one operating button for three of them; The said three drain valves include the drain valves of 1-6 segments extraction pipeline. LBA41AA560VC Pneumatic drain valve of the main steam pipe LBA41AA560VC Open conditions of interlock Load less than or equal to 10% Steam turbine trip Generator trip Closure conditions of interlock Load greater than 10% Low-low condenser vacuum (similarly to the said drain valves) (with the use of an analogue value less than 50kpa) Pneumatic drain valves of main steam pipe on the left and right sides LBA21AA560VC/ LBA31AA560VC Open conditions of interlock Load less than or equal to 10% Steam turbine trip Generator trip Closure conditions of interlock Load greater than 10% Low-low condenser vacuum (similarly to the said drain valves) (with the use of a analogue value less than 50kpa) Pneumatic drain valves of main steam pipe on the left and right sides LBA21AA560VC/ LBA31AA560VC Closure conditions of interlock Load less than or equal to 20% 35
Steam turbine trip Generator trip Closure conditions of interlock Steam turbine more than 20% Low-low condenser vacuum Pneumatic drain valves of upper and lower valve blocks of right and left main steam valves MAL70AA560VO/ MAL30AA560VO/ MAL60AA560VO/ MAL40AA560VO Closure conditions of interlock Load less than or equal to 10% Steam turbine trip Generator trip Closure conditions of interlock Steam turbine greater than 10% Low-low condenser vacuum Pneumatic drain valves of right and left RSV 1/2 MAL10AA560VO/ MAL20AA560VO Closure conditions of interlock Load less than or equal to 10% Steam turbine trip Generator trip Closure conditions of interlock Steam turbine greater than 10% Low-low condenser vacuum Pneumatic drain valve for outlet of the HP control valve MAL50AA560VO Closure conditions of interlock Load less than or equal to 10% Steam turbine trip Generator trip Closure conditions of interlock Steam turbine greater than 10% Low-low condenser vacuum Over-speed protection control system action (OPCACT for short) Steam turbine trip Generator trip Following valves will automatically open in case that the load is less than 10% of the rated. Steam turbine trip Generator trip Over-speed protection control system action (OPCACT for short) Drain valve of the left main steam pipe 36
Drain valve of the right main steam pipe Drain valve of HP steam conduit Drain valve for the left upper valve block of the HP MSV Drain valve for the left lower valve block of the HP MSV Drain valve for the right upper uppe r valve block of the HP MSV Drain valve for the right lower valve block of the HP MSV Drain valve for the left exhaust pipe of the HP cylinder Drain valve for the right exhaust pipe of the HP cylinder Drain valve for the exhaust manifold of the HP cylinder Outlet drain valve for the 1st 1 st extraction electric valve Inlet drain valve for the 1st extraction electric valve Outlet drain valve for the 2nd extraction electric valve Inlet drain valve for the 2nd extraction electric valve Drain valve of HP bypass pipe Following valves will automatically close in case that the load is greater than 10%: Low-low condenser vacuum Drain valve of the left main steam pipe Drain valve of the right main steam pipe Drain valve of HP steam conduit Drain valve for the left upper valve block of the HP MSV Drain valve for the left lower valve block of the HP MSV Drain valve for the right upper uppe r valve block of the HP MSV Drain valve for the right lower valve block of the HP MSV Drain valve for the left exhaust pipe of the HP cylinder Drain valve for the right exhaust pipe of the HP cylinder Drain valve for the exhaust manifold of the HP cylinder Outlet drain valve for the 1st extraction electric valve st
Inlet drain valve for the 1 extraction electric valve Outlet drain valve for the 2nd extraction electric valve Inlet drain valve for the 2nd extraction electric valve Drain valve of HP bypass pipe Following valves will automatically open in case that the load is less than 20%: Steam turbine trip Generator trip Over-speed protection control system action (OPCACT for short) Drain valve of left reheat steam p ipe Drain valve of right reheat steam pipe Drain valve of left IP union valve 37
Drain valve of right IP union valve Inlet drain valve of 3ird extraction e xtraction electric valve Outlet drain valve of 3ird extraction e xtraction electric valve Inlet drain valve of 4th extraction electric valve th
Outlet drain valve of 4 extraction electric valve Following valves will automatically close in case that the load is greater than 2 20%: 0%: Low-low condenser vacuum Drain valve of left reheat steam pipe Drain valve of right reheat steam pipe Drain valve of left IP union valve Drain valve of right IP union valve Inlet drain valve of 3ird extraction electric valve Outlet drain valve of 3ird extraction e xtraction electric valve Inlet drain valve of 4th extraction electric valve th
Outlet drain valve of 4 extraction electric valve Following valves will automatically open in case that the load is less than 30%: Steam turbine trip Generator trip Over-speed protection control system action (OPCACT for short) Inlet drain valve of 5th extraction electric valve Outlet drain valve of 5th extraction electric valve Inlet drain valve of 6th extraction electric valve Outlet drain valve of 6th extraction electric valve Following valves will automatically close in case that the load is greater than 3 30%: 0%: Low-low condenser vacuum th
Inlet drain valve of 5 extraction electric valve Outlet drain valve of 5th extraction electric valve th
Inlet drain valve of 6 extraction electric valve th
Outlet drain valve of 6 extraction electric valve Drain valve for the left exhaust pipe of the HP cylinder High-high water level in the drain pot triggers the drain valve to open, whereas to close. Drain valve for the right exhaust pipe of the HP cylinder High-high water level in the drain pot triggers the drain valve to open, whereas to close. Drain valve for the exhaust manifold of the HP cylinder High-high water level in the drain pot triggers the drain valve to open, whereas to close. Drain valve for the exhaust pipe at the inlet A of the LP bypass valve High-high water level in the drain pot triggers the drain valve to open, whereas to close. Drain valve for the exhaust pipe at the inlet B of the LP bypass valve 38
High-high water level in the drain pot triggers the drain valve to open, whereas to close. Drain valve for the exhaust pipe at the outlet A of the LP bypass valve High-high water level in the drain pot triggers the drain valve to open, whereas to close. Drain valve for the exhaust pipe at the outlet B of the LP bypass valve High-high water level in the drain pot triggers the drain valve to open, whereas to close. Steam turbine trip or generator asynchronous protection or OPC action will close the left exhaust check valve of the HP cylinder. Steam turbine trip or generator asynchronous protection or OPC action will close the right exhaust check valve of the HP cylinder.
2.1.5 Interlock protection for lubricating oil system of mainframe 2.1.5.1 The turbine AC auxiliary pump is self-driven in case of meeting one of following conditions: 1) Low outlet pressure of the main oil pump 2) The period before turbine rotating speed down to 2900r/min 3) Low lube oil 4) Steam turbine trip 2.1.5.2 The manual shutdown of the turbine AC auxiliary pump is available in case of meeting one of following conditions: 1) Zero rotating speed of steam turbine 2) Stable and constant rotating speed of the steam turbine up to 3000r/min and normal lube oil pressure 2.1.5.3 The mainframe startup pump (MSP) is self-driven in case of meeting one of following conditions: 1）Turbine rotating speed less than or equal to 2850 r/min 2）Low inlet pressure of the main oil pump (MOP) (less than
Mpa)
3）Steam turbine trip. 2.1.5.4 The manual shutdown of the mainframe startup pump (MSP) is available in case of meeting one of following conditions: 1) Stable and constant rotating speed of the steam turbine up to 3000r/min 30 00r/min 2) Zero rotating speed of steam turbine. 2.1.5.5 The DC emergency oil pump (EOP) is self-driven in case of meeting one of following conditions: 1) Non-zero rotating speed of the steam turbine and low-low lube oil pressure of the mainframe (less than
Mpa)
2) Standby AC lube oil pump startup with the AC lube oil pump trip 3）Low inlet pressure of the MOP and TOP. TOP. 2.1.5.6 The manual shutdown of the DC emergency oil pump (EOP) is available in case of meeting one of following conditions: 39
1) Zero rotating speed of steam turbine 2) Normal lube oil pressure (0.137Mpa- 0.176Mpa). 2.1.5.7 The startup of the mainframe jacking oil pump is allowable under the following condition: 1) Inlet pressure of the jacking oil pump more than 0.03Mpa 2.1.5.8 The mainframe jacking oil pump is allowable for shutdown in case of meeting one of following conditions: 1) The AC auxiliary oil pump out of service 2) The turbine rotating speed is greater than or equal to 2000r/min (tentative speed) 3) Allowable for one standby in two sets of jacking oil pump 2.1.5.9 The jacking oil pump is self-driven in case of meeting one of following conditions: 1）When the rotating speed of the steam turbine MAA00CS002 is less than 2000, a specified standby pump will bring into action; if the standby delays 10s, the other one will be put into operation; 2）When the rotating speed of the steam turbine MAA00CS002 is less than 2000, the working pump is in operation and the outlet manifold pressure of the jacking oil pump is low, the standby jacking oil pump is put into operation; 3）When the rotating speed of the steam turbine MAA00CS002 is less than 2000 and the working pump trips, the standby jacking oil pump is brought into action. 2.1.5.10 the jacking oil pump automatically stops in case of meeting one of following conditions: 1) Rotating speed of the steam turbine is greater than or equal to 2000r/min (tentative speed); 2）60s delay time of the steam turbine at zero rotating speed 2.1.5.11 the electric heater of the lube oil box is self-driven in case of meeting one of following conditions: 1) Lube oil temperature in the main oil tank less than 32℃ 2）Surface temperature of the electric heater of the main oil tank less than 100℃ 2.1.5.12 the electric heater of the main lube oil automatically stops in case of meeting one of following conditions: 1) High lube oil temperature in the main oil tank greater than 37℃ 2) High surface temperature of the electric heater of the main oil tank greater than 150℃ 2.1.6 Interlock protection for EH oil system of the mainframe 2.1.6.1 The EH oil pump is allowable for starting in case of full meeting following conditions: 1) Main EH oil pump allowable for being operated 2) Normal oil level of the EH oil tank 3）20℃ Oil temper temperatur ature e of the the EH oil oil tank tank high higher er than than 20℃ 2.1.6.2 The standby EH oil pump will automatically start in case of meeting one of following conditions: 1) One One set in operation and pressure of the EH oil manifold less than or equal to 2) Motor trip of a EH oil process pump 40
Mpa
2.1.6.3 The EH oil pump will automatically stop in case of meeting one of following conditions: 1）Excessively low oil level of the EH oil tank (less than negative 200mm) 2）Breaker trip of the EH oil pump or overload protection of the motor in action 2.1.6.4 The electric heater of the EH oil tank will automatically au tomatically start in case of full meeting following conditions: 1）Normal oil level of the oil tank 2）#1 and #2 circulating pumps of the oil tank in operation 3）The breaker of the heater at on-position 4）Oil temperature less than or equal to 20℃ 2.1.6.5 The electric heater of the EH oil tank will automatically stop in case of meeting one of following conditions: 1）The oil temperature greater than or equal to 35℃ 2）The breaker of the heater tripped 3）Excessively low oil level 4）Both the #1 circulating pump and #2 circulating pump of the oil tank out of service 2.1.7 Turning gear interlocks protection of the mainframe 2.1.7.1 The turning gear will automatically start in case of full meeting following conditions: 1) The interlock switch of its motor at AUTO position 2) Lube oil pressure of the bearing greater than 0.103MPa 3) Jacking oil pressure of every bearing greater than or equal to 3.43MPa 4) A manual turning interlock switch in standby 5) Both of the MSV in fully closed state 6) Zero rotating speed of the steam turbine and 30s delay time 2.1.7.2 The turning gear will automatically trip in case of meeting one of following conditions: 1) Jacking oil pressure of any bearing less than 2.7Mpa 2) Lube oil pressure less than or equal to ≤0.07Mpa 3) Overload protection for the turning motor in action 2.1.8 Control and interlock protection of HP and LP bypass system 2.1.8.1 Control mode of the HP and LP bypass system Decentralized control system (DCS) control modes of the HP bypass system: minimum opening, boost, fixed pressure and follow modes DCS control modes of the LP bypass system: minimum opening, fixed pressure and track modes 2.1.8.2 Bypass attemperating water control 1) The control modes include AUTO and MAN; in the AUTO mode, the outlet temperature of the bypass valve is able to be automatically regulated by setting the inlet temperature of the HP bypass valve; in another case, the outlet temperature is maintained through manually controlling the opening of an attemperating water valve by the operator. Meanwhile, automatic control mode 41
of the HP bypass pressure into operation is to bring the HP bypass attemperating water control mode automatically into operation. 2) The control modes of the LP bypass attemperating water include AUTO and MAN; in the AUTO mode, the outlet temperature of it is automatically controlled at 160℃ ; in another an other case, the outlet temperature is maintained through manually controlling the opening of an attemperating water valve by the operator. Meanwhile, the automatic control mode of the LP or HP bypass pressure into operation is to bring the LP bypass attemperating water control mode automatically into operation. 2.1.8.3 Interlock protection of bypass 1）HP bypass pressure reducing valve Allowable fast-opening conditions: Pressure to be regulated to greater than or equal to 30% prior to triggering the fast-opening action In HP cylinder control before triggering the fast-opening action Bypass in operation No fast-closing condition (the fast-closing in prior to the fast-closing) Trigger conditions of fast-opening A changeover switch has h as already put into operation. The HP cylinder control is put into operation and the steam turbine trips. Fast-closing conditions: 5s duration at an outlet temperature of the HP bypass valve higher than 380℃ 0% opening 2）HP bypa bypass ss spra spray y val valve ve (set (set temp temper eratu ature re rang rangin ing g from from 250 250℃ to 330℃ ) Fast-opening condition: The fast-opening of the HP bypass pressure valve is available. Fast-closing condition: The fast-closing of the HP bypass pressure valve is available. Less than 2.5% opening of the HP bypass pressure control valve (PCV) is to jointly close the LP bypass PCV after 5s de lay time. 3）HP bypass spray isolation valve 1. The spray isolation valve is triggered to open in case that the opening of the HP bypass valve is greater than or equal to 2.5%; 2. The spray isolation valve is triggered to close after 15s delay in case that the opening of the HP bypass valve is less than 2.5%. 4）LP bypass pressure reducing valve Fast-closing conditions include， but not limit to, the following: 1. Low condenser vacuum 2. High condenser temperature 42
3. Low spray pressure of the LP bypass spray valve 4. High outlet steam temperature o f the LP bypass spray valve Fast-closing opening: 0 Fast-opening conditions (the fast-closing in prior to the fast-opening) include, but not limit to, the following: 1. Reheater pressure more than 4.4Mpa 2. Fast-opening of the HP bypass valve is available. Opening: The LP bypass pressure valve is put into control mode as it is pre-opened to 80% and in automatic operation. 5）LP bypass spray valve Fast-closing condition: Fast-closing of the LP bypass pressure reducing valve is available. Fast-closing opening: 0 Fast-opening condition: Fast-Opening of the LP bypass pressure reducing valve is available. Opening: The LP bypass pressure valve is put into control mode as it is pre-opened to 80% and in automatic operation. 6）LP bypass spray isolation valve 1. The spray isolation valve is jointly opened as the opening of the LP bypass valve is greater than or equal to 2%; 2. The spray isolation valve is jointly closed as the op ening of the LP bypass valve is less than 2%; 2.1.9 Turbine supervisory instrument (TSI) 2.1.9.1 Rotating speed supervision (revolution indicator and electric over-speed protection 2.1.9.2 Vibration supervision on the #1-#8 bearing shells 2.1.9.3 Vibration supervision on X and Y directions of the #1-#8 bearings 2.1.9.4 Supervision on axial displacement 2.1.9.5 Differential expansion supervision on the HIP and LP cylinders 2.1.9.6 Eccentricity monitoring 2.1.9.7 ；Supervision on right and left heat expansion of the HIP cylinder 2.1.9.8 Precision transient tachometer (tachometer equipped at the head of a motor) 3. Thermal Interlock Protection of Au xiliaries 3.1 Thermal Interlock and Protection of Turbine Auxiliaries
3.1.1 Interlock protection of turbo-feed pump 3.1.1.1 The A/B booster pumps are allowable for starting in each of following conditions: Water level of the deaerator in normal condition (LAA10CL501L NOT) (based on the analogue value) The electric valves of the A/B booster pumps at the inlets to be opened in place LAA30CZ130ZO 43
The electric valve of the A turbo-feed pump at the outlet to be closed in place LAC10CZ130ZC The re-circulating electric valves of the A/B turbo-feed pumps to be opened in place The minimum flow control valves of the A/B turbo-feed pumps to be opened in place Radial bearing temperature of the driving ends of the A/B turbo-feed pumps’ booster pumps LAA01CT381 Radial bearing temperature of the free ends of the A/B turbo-feed pumps’ booster pumps LAA01CT383 Radial bearing temperature of the motor driving ends of the A/B turbo-feed pumps’ booster pumps LAA01CT403 Radial bearing temperature of the motor free ends of the A/B turbo-feed pumps’ booster pumps LAA01CT401 The stator phase winding temperature of the motors of the A/B turbo-feed pumps’ booster pumps are ultra-limit. No tripping condition No motor protection for the A/B turbo-feed pumps’ booster pumps (no contact point) Normal inlet pressure of the feed pump (more than 1.4MPa) 3.1.1.2 The A/B booster pumps trip by interlock in any one of following conditions: Low-low water level of the deaerator LBD04CL203 The minimum flow control valves and the re-circulating electric valves of the A/B turbo-feed pumps have already closed in place. The inlet minimum flow is less than 270T/H and delay time is 15s when any one of the valves is closed. The inlet electric valves of the A/B booster pumps to be closed in place after 3s delay in operation The radial bearing temperature of the driving ends LAA01CT381 and the free ends LAA01C LAA01CT38 T383 3 of the A/B A/B boost booster er pumps pumps more more than than 100℃ during during 3s 3s delay delay The bearing temperature of the motor driving ends LAA01CT403 and non-driving ends LAA01C LAA01CT40 T401 1 of the A/B A/B boost booster er pumps pumps more more than than 90℃ during during 3s dela delay y Stator phase winding temperature of the motors of the A/B booster pumps more than 130 130℃ duri during ng 3s del delay 3.1.1.3 The A/B booster pumps are allowable for starting in each of following conditions: Normal water level of the deaerator higher than 1950mm (median of three) The re-circulating electric valves of the A/B turbo-feed pumps to be opened in place The minimum flow control valves of the A/B turbo-feed pumps to be opened in place The motors of the A/B turbo-feed pumps’ booster pumps in operation LAA01AP001ZS The booster pumps in operation and the normal inlet pressure of the feed pump (more than 1.4MPa) The radial bearing temperature of the driving ends of the A/B turbo-feed pumps less than 44
75℃ The radial bearing temperature of the free ends less than 75℃ Inside temperature of the thrust bearings less than 80℃ Outside temperature of the thrust bearings less than 80℃ The thrust bearing temperature of the steam turbine for the A/B turbo-feed pumps less than 105℃ The electric exhaust butterfly valve of the steam turbine of the A/B turbo-feed pumps to be opened in place No tripping condition Normal lube oil pressure of the steam turbine for the A turbo-feed pump (more than 0.08MPa) The temperature difference of the upper and lower barrels of the pumps in normal condition condition (the (the temperatu temperature re differenc difference e of the upper and and lower lower parts parts not exceeding exceeding 30℃ ) Exhaust pressure not exceeding 1-value 3.1.1.4 The interlocks of the A/B turbo-feed pumps will trip in any one of following conditions: con ditions: Low-low water level of the deaerator Motors trip of the A/B turbo-feed pumps’ booster pumps The minimum flow control valves and the re-circulating electric valves of the A/B turbo-feed pumps have already closed in place. The inlet minimum flow is less than 270T/H and delay time is 15s when any one of the valves is closed. The radial bearing temperature of the driving ends of the A/B booster pumps
more
than than 100 100 (90 (90))℃ duri during ng 3s 3s del delay ay The bearing temperature of the free ends of the A/B booster pumps more than 100 (90) ℃ during 3s delay
Inside temperature of the thrust bearings less than 100(110) ℃ during 3s delay Outside temperature of the thrust bearings more than 100(110) ℃ during 3s delay The thrust bearing temperature of the steam turbine for the A/B turbo-feed pumps more than 120(110)℃ during 3s delay The inlet pressure of the A/B turbo-feed pumps less than 1.0MPa during 10s delay Alarm in case that the front bearings of the steam turbine for the A/B turbo-feed pumps horizontally and vertically vibrate or any one of the bearings vibrate. The exhaust electric butterfly valve of the steam turbine for the A/B turbo-feed pumps in closed state Water temperature different at the inlet and outlet more than 3.1.1.5 Trip protection conditions of the steam turbine for the feed pump (METS) 1) Over-speed of the steam turbine for the feed pump (greater than or equal to 5972 r/min, two of three) 2) Low safety oil pressure (less than 6.0MPa, two of three) 45
3) Large axial displacement (positive 0.9mm, negative 0.9mm) 4) Large bearing vibration (greater than or equal to 0.15mm) 5) Low exhaust vacuum (negative 47.7kPa, one of two) 6) Lube oil pressure lower than 3-value (less than 0.08MPa, one of two) 7) Any one of the return oil temperature of the front bearing, the thrust bearing and the back bearings of the steam turbine for the feed pump greater than or equal to 75℃ 8) MEH required to trip 9) Trip single of the turbo-feed pump 10) Manual shutdown 3.1.1.6 Alarm single of the turbo-feed pumps 1) High radial bearing temperature of the free ends of the booster pumps (greater than or equal to 95 ℃ ) 2) The thrust bearing temperature of the free ends of the booster pumps greater than or equal to 95 ℃ 3) High radial bearing temperature of the driving ends of the booster pumps (greater than or equal to 95 ℃ ) 4) The motor bearing temperature of the driving ends of the booster pumps greater than or equal to 90 ℃ 5) High motor bearing temperature of the non-driving ends of the booster pumps (greater than or equal to 90 ℃ ) 6) High High motor coil temperature temperature of the booster pumps (greater (greater than or equal to 120 ℃ ) 7) High thrust bearings temperature (insides A and B, or outsides A and B) of the turb turboo-fee feed d pump pumps s (gre (great ater er than than 85℃ ) 8) High radial bearing temperature of the turbo-feed pumps (the driving ends or the free ends ends)) (gr (grea eate terr tha than n 100 100℃ ) 9) Low lube oil pressure (1-value less than 0.15MPa; 2-value less than 0.12MPa; 3-value less than 0.08MPa) 10) Outlet flow less than a given value (less than 270m3/h) 11) Low inlet pressure of the turbo-feed pump (less than 1.4MPa) 12) Low sealing water differential pressure of the turbo-feed pumps (1-value less than 0.035MPa and 2-value less than 0.015MPa) 13) Large temperature difference of the upper and lower barrels of the turbo-feed pumps (more than 30℃) 14) Over-speed of the steam turbine for the feed pump (greater than or equal to 5972 r/min) 15) Low safety oil pressure (less than 6.0MPa) 16) Large axial displacement (positive 0.8mm, negative 0.8mm) 17) Large bearing vibration (greater than or equal to 0.1mm) 46
18) Low exhaust vacuum (negative 67.7kPa) 19) Any one of the return oil temperature of the front bearing, the thrust bearing and the back bearings of the steam turbine for the feed pump greater than or equal to 65℃ 20) Any one of the front and back bearings and the thrust bearings temperature of the steam turbine for the feed pump greater than or equal to 75℃ 21) High filter differential pressure of the fire-resistant oil manifold (greater t han or equal to 0.35MPa) 22）High or low lube oil level of the oil tank (positive 150mm, negative 150mm) 23）High differential pressure of the lube oil filter (greater than or equal to 0.1MPa) 24）Bearing eccentricity of the steam turbine for the feed pump greater than or equal to 0.13mm 3.1.1.7 Minimum flow re-circulating valve and control valve o f the turbo-feed pump 3
1) Open interlock: outlet flow of the turbo-feed pump less than 270m /h or the turbo-feed pump out of service 3
2) Closed interlock: the outlet flow more than m /h 3.1.1.8 Outlet electric valve of the turbo-feed pump 1) Open interlock: the turbo-feed pump starts after
delay time
2) Closed interlock: the turbo-feed pump out of service (impulse) or rotating speed of the steam turbine for the feed pump less than 500 3.1.1.9HP main stop valve and drain valve (A/B) of the steam turbine for feed pump 1) Open interlock a) Load of the unit less than a given value (15%) b) Steam turbine trip c) The corresponding steam turbine for the feed pump trip 2) Closed interlock: the valves will automatically close after the said conditions are reset. 3.1.1.10 Electric vacuum exhaust butterfly valve of steam turbine for feed pump 1) Open interlock: corresponding steam turbine for feed pump trip 2) Closed interlock: corresponding steam turbine for feed pump trip 3.1.1.11Startup 3.1.1.11Startup of AC main oil pumps (A/B) interlock of the steam turbine for the feed pump 1) Outage of the process oil pump triggers the standby to start up; 2) The standby pump is jointly started in case of low-low lube oil pressure of the steam turbine for the feed pump (less than or equal to 0.12Mpa). 3.1.1.12 One of the following startup conditions should be met in need for the DC emergency oil pump’s interlock of the steam turbine for the feed pump, comprising: 1) Both of the AC oil pumps of the steam turbine for the feed pump trips due to failure. 2) The lube oil pressure of the steam turbine for the feed pump is low-low (less than or equal to 0.105Mpa). Note: The DC emergency oil pump of the steam turbine for the feed pump must be manually 47
stopped. 3.1.1.14 Startup and outage of lube oil tank's heater of the steam turbine for the feed pump 1) Interlock startup: Low oil temperature temperature of the lube oil tank tank (less than 25 ℃ ) 2) Interlock stop: High oil temperature temperature of the lube oil tank tank (more (more than 30 ℃ ) and high surface temper temperatu ature re of the the heat heater er (more (more than than 140 140℃ ) 3.1.2 Interlock protection of motor-driven feed pump 3.1.2.1 Startup conditions of the motor-driven feed pump (all the conditions are required to meet): No reverse alarm of the motor-driven feed pump happened LAA03CS102RT Inlet electric valve of the booster pump of the motor-driven feed pump to be opened already LAA10CZ130ZO The minimum flow control valve of the motor-driven feed pump to be opened already LAE30ZZ001 (greater than 95％) ）Lube oil pressure of the motor-driven feed pump in normal condition (not less than
LAC03CP215L and set to NOT)(greater than or equal to 0.15MPa) Water level of the deaerator’s water tank in normal condition (greater than 1950mm and median of three) Minimum location of a scoop tube LAC03ZZ001(less than 5%) Outlet electric valve of the motor-driven feed pump to be closed in place LAC30CZ130ZC Differential pressure of the inlet strainer of the motor-driven pump in normal condition Radial bearing temperature of inlet LAA03CT382 and outlet LAA03CT381 sides of the booster pump for the motor-driven feed pump less than 75℃ Thrust bearing temperature LAA03CT383 less than 75℃ Radial bearing temperature LAC03CT412 less than 80℃ Radial bearing temperature LAC03CT411 at hydraulic coupling end less than 80℃ Radial bearing temperature LAC03CT401 at the inlet side less than 75℃ Radial bearing temperature LAC03CT403 at the outlet side less than 75℃ Thrust bearings' temperature 1/2 of the motor-driven feed pump (LAC03CT405 and LAC03CT406) less than 75℃ Inlet oil temperature LAC03CT391 of the lube oil cooler of the hydraulic coupler less than 75℃ Outlet oil temperature LAC03CT391 of the lube oil cooler of the hydraulic coupler less than 55℃ A/B/C phase windings’ temperature of the motor’s motor ’s 1/2/3 stators of the motor-driven feed pump less than 120℃ Inlet temperature LAC03CT394 and outlet temperature LAC03CT393 of the working oil cool cooler er of of the the hydr hydrau auli lic c coupl coupler er les less s than than 110 110℃ and 75℃ , resp respec ecti tive vely ly Radial #1 bearing temperature 1/2/3/4/5/6/7/8/9/10 of the coupler less than 85℃ 3.1.2.2 Trip conditions of the motor-driven feed pump (one of these conditions is required to meet): 48
1) Low-low water level of the deaerator LBD04CL203 Low-low
lube
oil
pressure
of
the
motor-driven
feed
pump
LAC03CP212LL/LAC03CP213LL/LAC03CP214LL (less than or equal to 0.08MPa) The inlet electric valve LAA10CZ130ZC of the booster pump is closed when the motor-driven feed pump is in operation. High-high differential pressure of the inlet strainer (greater than 0.06MPa) As the motor-driven feed pump is in operation, any one of the minimum flow control valves is closed and the inlet flow is less than 164T/H with 10s delay. Radial bearing temperature of inlet LAC03CT401/outlet LAC03CT403 sides of the motor-driven feed pump greater than 100℃ 1/2 thrust bearings’（LAC03CT405 and LAC03CT406 ）temperature of the motor-driven feed pump greater than 100℃ Inlet LAC03CT394/outlet LAC03CT393 oil temperature of the working oil cooler of the hydraulic coupler greater than 130/70℃ Inlet LAC03CT391/outlet LAC03CT392 oil temperature of the working oil cooler of the hydraulic coupler greater than 80/65℃ Radial bearing LAC03CT412 temperature at the booster pump end of the motor-driven pump greater than 90℃ Radial bearing LAC03CT411 temperature at hydraulic coupler end of the motor greater than 90℃ Radial #1 bearing temperature 1/2/3/4/5/6/7/8/9/10 of the coupler greater than 90℃ As the pump LAC03AP001ZS is in operation, the inlet pressure LAC03CP001 is less than 0.8(1.25MPa) and delays 10s. Inlet and outlet water differential pressure greater than 3.1.2.3 Standby mode 1) Automatically operational conditions of the standby pump: a）Start the auxiliary oil pump; b）Open the outlet electric valve of the motor-driven feed pump; c）Open the minimum flow re-circulating valve of the motor-driven feed pump (greater than 95 ％).
2) Effective conditions of the standby pump: a）The inlet valve of the booster pump has opened already; b）The outlet valve of the motor-driven feed pump has opened already; c）The minimum flow re-circulating valve of the motor-driven feed pump has opened already; d）The startup condition of the feed pump is met; e）The feed pump is in outage state. 3) The standby pump in operation by interlock: Outage of any motor-driven feed pumps will trigger the standby to operate under the standby mode. 49
4) Exit from the standby mode a）Manually cut off the standby pump; b）Start the standby pump by the interlock; Exit the standby mode after 30s; c）Bring integrated protection of the feed pump in action 3.1.2.4 Startup/outage of an auxiliary oil pump interlock of th e motor-driven feed pump 1）The auxiliary oil pump is started up by the interlock as the motor-driven feed pump is p ut into standby. 2）The motor-driven feed pump in operation: In case of low lube oil pressure (less than or equa l to 0.15MPa), the auxiliary oil pump is started up by the interlock; whereas high lube oil pressure (greater than or equal to 0.3Mpa) will trigger the auxiliary oil pump to stop. 3）Outage of the motor-driven feed pump starts the auxiliary oil pump by the interlock, and then it is jointly stopped after 5m. 3.1.2.5 Inlet electric valve of the booster pump 1) Closure-allowable condition: the motor-driven feed pump out of service and the inlet electric valve to be closed in place LAC30CZ130ZC 2) Open interlock: when the motor-driven feed pump is put into standby, the interlock is opened. 3.1.2.6 Outlet electric valve of the motor-driven feed pump 1) Closed interlock: the motor-driven feed pump trip 2) Open interlock: the motor-driven feed pump in operation or standby 3.1.2.7 Minimum flow re-circulating control valve of the motor-driven feed pump 3
1) Open interlock: outlet flow of it less than 200m /h 3
2) Closed interlock: outlet flow of it greater than 400m /h 3.1.2.8 Alarm conditions of the motor-driven feed pump 3
3
1) Outlet flow of it less than 200m /h or greater than 400m /h 2) Low lube oil pressure (less than or equal to 0.15MPa) 3）Low inlet pressure (less than or equal to 1.4MPa and 30s delay) 4）High inlet oil temperature of the lube oil cooler of the hydraulic coupler (1-value greater than 65℃ and 2-val -value ue grea greate terr tha than n 70 70℃) 5）High outlet oil temperature of the lube oil cooler of the hydraulic coupler (1-value greater than 55℃ and 2-val -value ue grea greate terr tha than n 60 60℃ ) 6）Inlet oil temperature of the working oil cooler of the hydraulic coupler (scoop pipe orifice oil) (1-v (1-val alue ue great greater er than than 110℃ and and 2-val -value ue grea greate terr tha than n 130 130℃ ) 7）Outlet oil temperature of the working oil cooler of the hydraulic coupler (1-value greater than 75℃ and 2-val -value ue grea greate terr tha than n 85 85℃ ) 8) High High radial radial bearing bearing temperatur temperature e of the hydrauli hydraulic c coupler coupler (1-value (1-value greater greater than than 90℃ and 2-va 2-valu lue e gre great ater er than than 95℃ ) 9) High High stator stator winding winding temperatu temperature re of the motor motor (greater (greater than than 120℃ ) 10) High radial bearing temperature of the driving end of the motor-driven feed pump (1-value 50
grea greate terr than than 75℃ and and 2-val -value ue grea greate terr tha than n 90 90℃) 11) High radial bearing temperature of the free end of the motor-driven feed pump (1-value grea greate terr than than 75℃ and and 2-val -value ue grea greate terr tha than n 90 90℃) 12）High thrust bearing temperature (inside and outside) of the motor-driven feed pump (1-value grea greate terr than than 80℃ and and 2-val -value ue grea greate terr tha than n 95 95℃) 13）High radial bearing temperature of the driving end of the booster pump (1-value greater than 75℃ and 2-val -value ue grea greate terr tha than n 90 90℃ ) 14) High radial bearing temperature of the free end of the booster pump (1-value greater than 75℃ and 2-val -value ue grea greate terr tha than n 90 90℃ ) 15）High thrust bearing temperature (inside and outside) of the booster pump (1-value greater than 80℃ and 2-val -value ue grea greate terr than than 95℃ ) 16) High end bearing temperature of the motor coupling of the motor-driven feed pump (1-value grea greate terr tha than n 75 75℃ and and 2-val -value ue grea greate terr tha than n 80 80℃ ) 17) High end bearing temperature of the motor booster pump of the motor-driven feed pump (1-v (1-val alue ue grea greate terr tha than n 70 70℃ and and 2-val -value ue grea greate terr tha than n 80 80℃ ) 18) High differential pressure of the inlet strainer of the motor-driven feed pump (greater than 0.06MPa) 19）High differential pressure of the inlet strainer of the booster pump (greater than 0.06MPa) 20）High differential pressure of the lube oil strainer (greater than 0.06MPa) 21) Pump reversal
3.1.3 Control and interlock protection of HP heater and extraction system 3.1.3.1 Stop and startup sequences of HP heater function sub-group 1) Allowable sequence-control startup condition: Water level of the HP heater in normal condition 2) Startup sequence: Open the HP heater outlet valves LAC60CZ131ZO, LAC50CZ131ZO and LAC40CZ131Z; Open the HP heater inlet valves LAC60CZ130ZO, LAC50CZ130ZO and LAC40CZ130ZO; Close the bypass valves LAC61CZ130ZC, LAC51CZ130ZC and LAC41CZ130ZC; Open the drain valves at the outlets of the first/second/third extraction check valves and the drain valves at the inlets of the first/second/third extraction electric valves; Open the third extraction electric valve LBD30CZ130ZO; Open the second extraction electric valve LBD20CZ130ZO Open the first extraction electric valve LBD10CZ130ZO Open the first/second/third extraction check valves BD10CZ430ZO, LBD20CZ430ZO and LBD30CZ430ZO. 3) Stop sequence: Close the first/second/third extraction check valves LBD10CZ430ZC, LBD20CZ430ZC and LBD30CZ430ZC 51
Close the first extraction electric valve LBD10CZ130ZC; Close the second extraction electric valve LBD20CZ130ZC; Close the third extraction electric valve L BD30CZ130ZC Open the drain valves at the outlets of the first/second/third extraction check valves and the inlets of the electric valves; Open the bypass valves LAC61CZ130ZO, LAC51CZ130ZO and LAC41CZ130ZO; Close the HP heater inlet electric valves LAC60CZ130ZC, LAC50CZ130ZC and LAC40CZ130ZC Close the HP heater outlet electric valves LAC60CZ131ZC, LAC50CZ131ZC and LAC40CZ131ZC. 3.1.3.2 HP heaters disconnection (#1, #2 and #3 HP heaters disconnection) 1) The HP heaters disconnection occurs under any one of following conditions: Steam turbine trip Generator trip H-H-H water level Manual disconnection of the HP heaters OPC in operation 2) Activities after HP heaters disconnection: Close the first/second/third extraction check valves; Close the first/second/third extraction eletric valves; Open the drain valves at the inlet of the first/second/third extraction check valves and outlets of the eletric valves; Open the bypass valves of the #1, #2 and #3 HP heaters and close the inlet and outlet valves of the #1, #2 and #3 HP heaters; Open the emergency drain valves of the #1, #2 and #3 HP heaters; The first/second/third extraction check valves Allowable open conditions: The outlet electric valve of the HP heaters to be opened in place LAC60CZ131ZO as well as the inlet electric valve LAC60CZ130ZO High water level not greater than 2-value (less than
)
Interlock closure conditions: HP heaters disconnection OPC in operation U1007SOE:OPCACT U1007 SOE:OPCACT.CIN .CIN Steam turbine trip Generator trip The inlet LAC60CZ130ZC or outlet LAC60CZ131ZC electric valves of the HP heaters in closed condition Open conditions of the interlock: 52
The first extraction electric valve Allowable open conditions: The outlet electric valve LAC60CZ130ZO and the inlet electric valve LAC60CZ131ZO of the #1 HP heaters to be closed in place No first extraction electric valve failure LBD10CZ130ZF Allowable closure conditions: Interlock closure conditions: HP heaters disconnection Steam turbine trip Generator trip The inlet electric valve LAC60CZ130ZC and the outlet electric valve LAC60CZ131ZC of the #1 HP heaters to be closed OPC in operation Pneumatic drain valves of steam pipes at inlet and outlet of the first extraction electric valve Open conditions of the interlock HP heaters disconnection Steam turbine load less than 10% The first extraction electric valve LBD10CZ130ZC and check valve LBD10CZ430ZC in closure condition Upper and lower walls temperature difference of the first extraction steam pipe up to 42℃ OPC in operation Interlock closure conditions: 30s delay in case that said interlock conditions are not existed; The interlock is closed after 5m delay when the steam turbine load is greater than 10%. Pneumatic drain valve of the steam turbine of the first extraction check valve inlet Open conditions of the interlock: HP heaters disconnection Steam turbine load less than 10% The first extraction electric valve LBD10CZ130ZC or check valve LBD10CZ430ZC in closure condition The upper and lower walls temperature difference of the first extraction steam pipe up to 42℃ OPC in operation Interlock closure conditions: 30s delay in case that said closure conditions are not existed The interlock is closed after 5m delay when the steam turbine load is greater than 10%.
53
Logic control sequence of the second and third extraction electric valve, the pneumatic drain valve of the steam pipe of the electric valve inlet and outlet, the pneumatic drain valve of the steam pipe of the check valve inlet is similar to the first extraction valves. #1, #2 and #3 HP heaters inlet electric valves Allowable open conditions: #1, #2 and #3 HP heaters outlet electric valves to be opened in place NO HP heaters electric valve failure Water level of the HP heaters in normal condition Interlock closure conditions: 3s delay when the #1, #2 and #3 HP heaters outlet valves are changed over on-position HP heaters disconnection The HP heaters in operation and the bypass valve to be closed #1, #2 and #3 HP heaters outlet electric valves Allowable open condition: Water level of the HP heaters in normal condition Allowable closure condition: #1, #2 and #3 HP heaters inlet electric valves in closure condition Interlock closure conditions: HP heaters disconnection The HP heaters in operation (the bypass valve to be closed) or the inlet valves to be closed #1, #2 and #3 HP heaters electric bypass valves Allowable open condition: No failure Allowable closure condition: cond ition: #1, #2 and #3 HP heaters inlet and outlet electric valves in open state Open conditions of the interlock HP heaters disconnection 3s delay when the #1, #2 and #3 HP heaters inlet and outlet valves are changed over on-position #1 HP heaters emergency drain valve HP heaters emergency disconnection or H-H water level is to open the valve by the interlock. 1# HP heaters normal drain valve High water level of the #2 HP heater is to close the normal drain valve by the interlock. #2 HP heaters emergency drain valve HP heaters emergency disconnection or H-H water level is to open the valve by the interlock. #2 HP heaters normal drain valve High water level of the #3 HP heater is to close the normal drain valve by the interlock. #3 HP heaters emergency drain valve HP heaters emergency disconnection or H-H water level is to open the valve by the interlock. 54
#3 HP heaters normal drain valve H-H water level of the deaerator is to close the normal drain valve by the interlock. The third extraction check valve has opened already; the third extraction electric valve is allowed to open. The second extraction check valve has opened already; the second extraction electric valve is allowed to open. The first extraction check valve has opened already; the first extraction electric valve is allowed to open. 3.1.3.1 #1, #2 and #3 HP heaters interlock protection 1）Water level protection of the HP heaters a) Open corresponding pneumatic emergency drain control valves in case that water level of any HP heater reaches high I value (greater than or equal to positive 38mm); close it when the water level is normal. b) In case that water level of any HP heater reaches high II value (greater than or equal to positive 76mm) （1）Close the pneumatic normal drain control valve of upper-stage heater; （2）Open the emergency pneumatic drain control valve of upper-stage heate r.
c) In case that water level of any HP heater reaches high III value (greater than or equal to positive 120mm) (1) Disconnect the HP heater 2）HP heater disconnection a) HP heater disconnection conditions (one condition is required to meet) （1）Steam turbine trip （2）Generator trip （3）Water level of any HP heater up to high 3-value （4）OPC in operation
b) Linked objects and sequences of HP heaters disconnection （1）Close the #1, #2 and #3 HP heaters extraction electric valves; （2）Close the #1, #2 and #3 HP heaters extraction check valves; （3）Close the #1, #2 and #3 HP heaters normal drain valves; （4）Open #1, #2 and #3 HP heaters drain valves of the extraction electric valve inlet and the
extraction pneumatic check valve outlet; （5）Close the HP heaters inlet three-way valves; （6）Close the #1 HP heater outlet valve.
3）Low water level of the HP heater (less than or equal to negative 30mm) will interlock following devices: a) Alarm; b) Automatically electrify the HP heater emergency drain solenoid valve. 55
3.1.3.2 #5 and #6 LP heaters interlock protection (normal water level is 0mm) 1）LP heater water level protection a) Open corresponding pneumatic emergency drain control valves in case that water level of any LP heater reaches high I value (greater than or equal to 40mm); close it when the water level is normal. b) In case that water level of any LP heater reaches high II value (greater than or equal to 80mm) （1）Close the pneumatic normal drain control valve of upper-stage heater; （2）Open the emergency pneumatic drain control valve of upper-stage heate r.
c) In case that water level of any LP heater reaches high III value (greater than or equal to 120mm) 2）LP heater disconnection a）LP heater disconnection conditions (one condition is required to meet) （1）Steam turbine trip （2）Generator trip （3）Water level of any HP heater up to high 3-value （4）OPC in operation
b）Linked objects and sequences of LP heaters disconnection (1) Close the LP heater extraction electric valve of this stage; (2) Close the LP heater extraction che ck valve of this stage; (3) Open the drain valve of the LP heater extraction electric valve inlet and close it after 5m delay; (4) Open the drain valve of the LP heater extraction electric valve outlet and close it after 5m delay; (5) Open the corresponding LP heater water side bypass valve and close the inlet and outlet valves (close the corresponding outlet electric drain valve in case of the #5 LP heater disconnection); (6) Fully open the emergency pneumatic p neumatic drain control valve of this stage; (7) Fully close the pneumatic normal drain control valve of this stage; (8) Fully open the emergency pneumatic drain control valve of upper stage; (9) Fully close the pneumatic normal drain control valve of upper stage. 3）Low water level (less than or equal to negative 40mm) of the #5 and #6 LP heaters will interlock the following device. (1) Electrify the corresponding LP heater emergency pn eumatic drain control valve. 3.1.3.3 #7(A/B) and #8(A/B) LP heaters interlock protection 1）LP heater water level protection a）Open the corresponding #7(A/B) an d #8(A/B) LP heater emergency pneumatic drain control valves in case that water level of any LP heaters is up to high I value (greater than or equal to 56
50mm) or water level of the condenser is high 2-value (greater than or equal to 550mm); close the corresponding LP heater emergency pneumatic drain control valves in case that the water level of the LP heate rs of this stage is normal. b）High II values water level of any LP heater (greater than or equal to 90mm) （1）Close the pneumatic normal drain control valve of upper-stage heater; （2）Open the pneumatic normal no rmal drain control valve of upper-stage heater.
c）High III value water level of any LP heater (greater than or equal to 130mm): LP heater disconnection 2）LP heater disconnection a）LP heater disconnection conditions (one of those conditions is required to meet) （1）Steam turbine trip （2）Generator trip （3）High 3-value water level of any LP heater （4）OPC in operation
b）Linked objects and sequences of LP heater disconnection (1) Fully open the emergency pneumatic drain control valve of this stage LP heater; (2) Fully close the pneumatic normal drain control valve of this stage LP heat er; (3) Fully open the emergency pneumatic drain control valve of upper-stage LP heater; (4) Fully close the pneumatic normal drain control valve of upper-stage LP heate r; (5) Open the corresponding #7 and #8 LP heaters water-side bypass valves; （6）Close the #7(A/B) and #8(A/B) LP heaters inlet valves; （7）Close the #7(A/B) and #8(A/B) LP heaters outlet valves.
3.1.4 The fourth extraction control and interlock protection of deaerator water level 3.1.4.1 Startup and stop sequences of the fourth extraction functional sub-group 1）Startup sequences: Close the electric drain valve of the deaerator; Open the steam pipe pneumatic drain valve of the fourth extraction A check valve inlet and the fourth extraction B check valve outlet; Open the fourth extraction A/B check valves; Open the fourth extraction electric valve 1 after the deaerator water level (less than
) is
normal; Open the fourth extraction to deaerator steam supply electric valve 2(including pre-heating) and the fourth extraction steam pressure reaches a set value (greater than 0.15MPa); Close the steam pipe pneumatic drain valves of the fourth extraction A check valve inlet and the fourth extraction B check valve after 600s delay. 2）Stop sequences: Close the fourth extraction electric valve; Operate to the deaerator fourth extraction electric valve; 57
Close the fourth extraction A/B check valves; Open the steam pipe pneumatic valve of the fourth extraction A check valve inlet and the fourth extraction B check valve outlet. 3.1.4.2 The fourth extraction A/B check valves Interlock closure conditions: Steam turbine trip Generator trip H-H-H water level of the deaerator LBD04CL201 OPC in operation U1007SOE: OPCACT Deaerator pressure greater than 1.3MPa Deaerator pressure less than 0.15MPa and the pressure control valves from the auxiliary steam to the deaerator to be opened already 3.1.4.3 To To the deaerator fourth extraction electric valve 1） Allowable open condition: No failure occurred occurred at the segment to the fourth extraction extraction electric valve 2）Interlock closure conditions: Steam turbine trip Generator trip H-H-H water level of the deaerator LBD04CL201 OPC in operation The fourth extraction main electrical valve in closure condition LBD40CZ330Z Deaerator pressure greater than 1.3MPa Deaerator pressure less than 0.15MPa and the pressure control valves from the auxiliary steam to the deaerator to be opened already 3.1.4.3 The fourth extraction electric valve 1） Allowable open conditions: Steam turbine trip No fourth extraction electric valve failure 2） Allowable closure condition 3）Interlock closure conditions Steam turbine trip Generator trip H-H-H water level of the deaerator LBD04CL201 OPC in operation Deaerator pressure greater than 1.3MPa Deaerator pressure less than 0.15MPa and the pressure control valves from the auxiliary steam to the deaerator to be opened already 3.1.4.4 The fourth extraction A/B check valves inlet and o utlet steam pipe drain valve 58
(1) Open conditions of the interlock a) Steam turbine trip b) Generator trip c) Steam turbine load less than 20% d) The fourth extraction main electric valve or A/B check valves in closure condition e) The top and bottom temperature difference of the fourth extraction steam pipe in exceed of 50℃ f) H-H-H water level of the deaerator g) OPC in operation (2) Interlock closure condition h) 15s delay in case that the said conditions are not existed 3.1.4.5 The fourth extraction steam supply electric valve (to an auxiliary steam header) Allowable open condition: No failure of the fourth extraction steam supply electric valve Interlock closure conditions: Steam turbine trip Generator trip The fourth extraction main electric valve L BD40CZ330ZC in closure condition OPC in operation 3.1.4.6 Deaerator overflow The overflow is linked to open in case of H-H water level of the deaerator, whereas it is closed. 3.1.4.7 The deaerator overflow valve drains water to the electric valve of the Intermittent blow-down flash tank. Opening of the overflow valve and high water level of the condenser hot well links the electric valve to open; Closure of the overflow valve jointly closes th e electric valve. 3.1.4.8 The deaerator overflow valve drains water to the drain flash tank’s electric valve of the condenser. Opening of the overflow valve and non-high water level of the condenser hot well links the electric valve to open; Closure of the overflow valve jointly closes th e electric valve. 3.1.4.9 Deaerator electric drain valve Allowable open condition: No failure occurred at the electric drain valve Open condition of the interlock: high 3-value of the deaerator water level (LBD04CL201） Interlock closure condition: Normal water level less than 1950MM 3.1.4.10 the fourth extraction steam to electric valve of A/B steam turbine for feed water pump Allowable open condition: No failure Interlock closure conditions: 59
Steam turbine trip Generator trip The steam turbine for feed water pump in outage (FROM MEH） The steam turbine for feed water pump trip (FROM MEH） OPC in operation Deaerator vent valve High deaerator pressure links the vent valve to open (greater than or equal to 1.0Mpa); Non-high pressure links the vent valve to close (less than 1.0Mpa).
3.1.5 Interlock protection of condensate system Sequence-control functional group of A/B condensate pump Startup sequences of A/B condensate pump sub-group: Open the re-circulating valve 1LCG10CZ060ZO; Close the outlet valve LCA21CZ130ZC of the A/B condensate pump; Open the inlet electric valve LCA11CZ400ZO of the A/B condensate pump; Start the A/B condensate pump LCE01AP001ZS; Open the outlet valves LCA21CZ130ZO of the A/B condensate pumps; Release the minimum flow valve. Stop sequences of A/B condensate pump sub-group Open the minimum flow valve; Close the A/B condensate pump outlet valve LCA21CZ130ZC; Stop the A/B condensate pump; Release the minimum flow valve A/B condensate pump Allowable startup conditions: Condenser water level in normal conditions (10MAG01CL101 condensers A/B water level greater than 600mm ) Inlet electric valves of the A/B condensate pumps to be opened in place LCA11CZ400ZO 100% opening of the outlet electric valve of the standby condensate pump in operation or the outlet electric valves of the A/B condensate pumps to be closed in place LCA21CZ130ZC Motor lower bearing temperature of the A condensate pump LCE01CT405 less than 70℃ Motor thrust bearing temperature of the A condensate pump LCE01CT401 less than 70℃ Motor stator winding temperature of the A/B condensate pumps less than 110℃ A/B condensate pumps thrust bearing temperature LCE01CT412 and LCE01CT413 less than 75℃ No trip condition Interlock startup conditions: The interlock is started as the standby condensate pump is put into operation and the 60
process pump trips. The interlock is started at 3s delay as the standby condensate pump and the process pump are put into operation, and the condensate pump outlet manifold pressure is low (less than 2.7). Interlock trip conditions: Low-low condenser water level (condensers A/B water level lower than 280mm) and 20s delay The A condensate pump motor lower bearing temperature LCE01CT405 greater than 80℃ The A condensate motor thrust bearing temperature LCE01CT401 greater than 80℃ The A/B condensate pumps thrust bearing temperature LCE01CT412 and LCE01CT413 greater than 80℃ When the condensate pump is in operation, the inlet electric valve is closed in place LCA11CZ400ZO. When the condensate pump is in operation, the outlet electric valve is closed in place after 30s delay LCA21CZ130ZC. Sum of condensate flow and re-circulating flow less than 380t/h Large vibration Standby condensate pump self-start conditions: 1) Standby interlock in operation a) Open the condensate pump outlet electric valve. 2) Standby effective conditions: a) The condensate pump inlet valve to be opened already b) The condensate pump outlet valve to be opened already c) The condensate pump startup condition to be met (except that the minimum flow re-circulating control valve is opened to the maximum position) d) The condensate pump at outage state 3) Exit the standby mode a) Manually cut off the standby mode; b) Start the standby condensate pump by the interlock and exit the standby mode after 30s in operation; c) The integrated protection of the condensate pump is in operation. A/B condensate pumps’ inlet electric valves Allowable open condition: No failure occurred at the inlet electric valves Allowable closure conditions: This condensate pump is out of service; This condensate pump is not allowed to stop in operation. Open condition of the interlock The standby condensate pump has put into operation. 61
A/B condensate pumps’ outlet electric valves Allowable open and closure condition: No failure occurred at the inlet electric valves of the A/B condensate pumps Open condition of the interlock: This standby condensate pump has put into operation or the condensate pump LCE01AP001ZS is in operation at 5s delay time. Interlock closure condition: This condensate pump LCE01AP001ZS is in operation Minimum flow re-circulating valve of the condensate pump (long instruction) Allowable open condition: No fault signal Open conditions of the interlock: a) Low flow 350T/H b) Interlock startup in case of high 2-value water level Interlock closure condition: High condensate flow Deaerator water level-control electric bypass valve Allowable open condition: No fault signal Open condition of the interlock: this valve is opened by the interlock at 10s delay time in case that the condensate pump in operation and the deaerator water level is low. Interlock closure condition: This valve is closed by th e protection of the interlock in case of high water level. Deaerator water level main control valve This valve is closed by the interlock in case of high water level. Make-up water control valve of the condensate hot well (electric bypass valve) Allowable open condition: Fault signal The valve is closed by the interlock in case of high hot well water level, but not high release. The valve is opened in case of low water level. Attemperating water control valve inlet electric valve of condenser drain flash tank I Open the attemperating water control valve in case of high exhaust temperature of the drain flash flash tank tank I (grea (greater ter than than or equal equal to 60℃ ); Close the attemperating water control valve in case of low exhaust temperature of the drain flash tank I. Low bypass tertiary attemperator (HP condenser) spray control valve inlet electric valve Opening the LP bypass valve will link the tertiary attemperating water control valve to op en. Closing the LP bypass valve will link the tertiary attemperating water control valve to close. Attemperating water control valve inlet electric valve of condenser drain flash tank II Open the attemperating water control valve in case of high exhaust temperature of the drai drain n flash flash tank tank II (greate (greaterr than than or equal equal to to 60℃ ); Close the attemperating water control valve in case of low exhaust temperature (less than or equ equal al to to 50℃ )of )of the the drai drain n flas flash h tank tank II. II. 62
Low bypass tertiary attemperator (LP condenser) spray control valve inlet electric valve Opening the LP bypass valve will link the tertiary attemperating water control valve to ope n. Closing the LP bypass valve will link the tertiary attemperating water control valve to close. Temperature and pressure reducer control valve bypass electric valve from condensate to sealing steam of the steam turbine
3.1.6 Condenser and vacuum system A/B vacuum pumps Allowable startup conditions: Inlet pressure of the A/B vacuum pumps LFA01CP201N/LFA02CP201N in normal condition Inlet valves of the A/B water-ring vacuum pumps LFA21CZ100ZC/ LFA22CZ100ZC to be closed in place Interlock startup conditions: Prepare the standby vacuum pump into operation; in case that any one of the main vacuum pumps trips, the standby pump is jointly started. The interlock in operation and low condenser vacuum. Inlet valves of A/B water-ring vacuum pumps Allowable open and closure conditions: Interlock closure condition: The corresponding pump trip LFA01AP001ZD Open condition of the interlock: The corresponding vacuum pump startup LFA01AP001ZS and allowable opening of the vacuum pump inlet valve LFA01CP202 A condenser electric vacuum break valve Allowable open conditions: Steam turbine trip No electric vacuum break valve failure B condenser electric vacuum break valve Allowable open conditions: Steam turbine trip No electric vacuum break valve failure A/B vacuum pump make-up solenoid valve The make-up solenoid valve of the steam-water separator automatically opens in case of the vacuum or standby pump in operation and low water level of the separator. The make-up water valve automatically closes at 10s delay in case of high water level of th e vacuum pump. 3.1.7 Gland sealing and auxiliary steam systems of the steam turbine A/B gland extraction fan Allowable startup condition 63
Interlock startup conditions: Prepare the standby gland extraction fan into operation; the standby gland extraction fan is jointly started in case that the gland extraction fan in operation trips. Gland pressure greater than or equal to 5KPa Gland steam temperature pneumatic control valve inlet electric valve Allowable open o pen condition: No fault of the gland steam temperature pneumatic control valve inlet electric valve MAW20AA230ZF Bypass valve of gland LP steam source pressure control valve Allowable open condition: No fault of the gland LP steam source pressure control valve bypass valve MAW10AA233ZF Bypass valve of gland overflow station control valve Allowable open condition: No fault of the bypass valve of gland overflow station control valve Emergency electric drain valve of gland cooler High water level of the gland cooler links the valve to open; The valve is closed in case that the water level of the gland cooler is normal. Open conditions of the gland overflow control valve interlock High pressure of the gland steam supply manifold (greater than 0.18MPa) Interlock closure condition of the gland overflow control valve Low pressure of the gland glan d steam supply manifold (less than or equal to 0.118MPa) Open condition of the gland overflow electric valves A/B interlock The gland overflow control valve to be open already Interlock open conditions of main gland steam pressure control valve Low pressure of the gland steam supply manifold (less than 0.13 MPa) Interlock closure condition of main gland steam, auxiliary gland steam and cooling gland steam pressure control valve High gland steam manifold pressure (greater than 0.18MPa) 3.1.8 Interlock protection of generator sealing oil system A/B main sealing oil pumps motor Allowable startup conditions No fault Oil level of vacuum oil tank in normal condition At remote Open conditions of the interlock Prepare the standby and then put it into operation in case of low manifold pressure of the sealing oil pump outlet MKW10CP201 Prepare the standby and then put it into operation after main oil pump trip Trigger the sealing oil main pumps (A/B) to stop in case of low oil level in the sealing oil vacuum 64
oil tank. Emergency stealing oil pump motor Allowable startup conditions: No fault At remote Interlock startup conditions: Prepare the standby and then trigger it into operation after 6s delay in case of low manifold pressure of the sealing oil pump outlet MKW10CP201 and two sets of the sealing oil pump in operation; Put it in standby in case of low oil level of the sealing oil vacuum oil tank MKW10CL002L; Put it in standby after 3s delay d elay in case that both of the A/B oil pumps trip. Sealing oil re-circulating oil pump motor Allowable startup condition: No fault Interlock startup conditions: Combined
interlock
startup
of
the
A/B
main
sealing
oil
pumps
MKW10AP001ZS/MKW10AP002ZS Emergency sealing oil pump MKW10AP003ZS Sealing oil vacuum pump motor Allowable startup condition: No fault Interlock stop condition: High oil level of the sealing oil vacuum oil tank MKW10CL002H 4. Unit Control and Manual Devices 4.1 Sequence Control System (SCS) 4.1.1 Sequence Control System (SCS) of Turbine Motor 4.1.1.1 Turbine turning gear sequence control 4.1.1.2 Fire-resistant oil sequence control of turbine lube oil 4.1.1.3 Turbine vacuum sequence control 4.1.1.4 LP heater sequence control 4.1.1.5 HP heater sequence control 4.1.1.6 Motor-driven feed pump sequence control 4.1.1.7 Turbo-driven feed pump sequence control 4.1.1.8 Generator water-cooled sequence control 4.1.1.9 Generator hydrogen-cooled sequence control 4.1.1.10 Generator sealing oil sequence control
65
motor
4.2 Analogue Control System (MCS) 4.2.1 The turbine-boiler coordinated control system, through serving the boiler and turbine generating set as an integer to control and
enabling the functions of automatic manual,
logic control and interlock protection to organically combine, is formed into an integrated control system with multiple control functions that are able to meet the control requirements of various operating modes and conditions. 4.2.1.1 Unit control modes: There are totally four modes for the turbine-boiler coordinated control system 1) Coordinated control mode (CCSMODE): main control modes of the steam turbine and the boiler are totally put into operation; 2) The main control mode of the steam turbine is manual; the boiler is automatic and the boil main control mode is used for regulating main steam pressure; 3) Turbine follow mode（TFMODE）: The main control mode of the steam turbine is automatic; the main control mode of the boiler is manual and the former one is used for regulating the main steam pressure; 4) Base mode (BASE): main control modes of the steam turbine and the boiler are manual. 4.2.1.2 Unit target load formation 1) Automatic generation control: in case that the unit is in stable operation and the coordinated control mode (CCSMODE) had put into operation, manually send out a UNIT REMO ALLOWABLE command; send a “AGC (automatic generation control) in operation signal” to the distributed control system (DCS) after the system control room makes a judgment that the AGC can be put into operation; then receive an ADS (automatic dispatching system) by the operator and trigger the UNIT REMO/LOCAL HANDOVER COMMAND；in case that the unit needs to an independent operation, the operator sends a command to cut off the ADS signal that triggers the UNIT REMO/LOCAL HANDOVER COMMAND at the same time and dispatches returning the AGC CUT-OFF CUT-OFF signal. Unit load circuit is of two modes that are manual and automatic modes. As the circuit is automatic, the unit is in AGC mode and the unit target load receives the ADS command; otherwise, the target load could be set by the operator (coordinated control mode) or through tracking the actual unit load （non-coordinated control mode）. The main control mode of the unit needs to be set to trace status in case of RUNBACK, RUNUP and RUNDOWN. 2） Allowable operating conditions of AGC a) Effective ADS signal b) The unit in coordinate operating mode c) No RUNBACK d) ADS command under limit 3) High-low limit: maximum and minimum limits of the unit target load are manually set by the operator. 66
4) Variable load rate limit The load rate is changed by a rate limit module and its limit value is set at an operator station by the operation. Besides, the direction blocking functions merely by increasing and reducing the blocking through setting the corresponding directional rate limit to zero. Blocking command increase and reduction conditions comprise a) Increased feed water control blocking b) Increased fuel blocking c) Increase main steam pressure blocking d) Increased air flow control blocking e) Increased induced air flow control blocking f) Increased primary air control blocking 5) Load forward and maintenance When the operator inputs a new target load at turbine-boiler coordinated control mode, the reset target load is effective after pressing the FORWARD/MAINTENANCE button; when the load set value reaches the target load, load automatically maintains. In case of AGC mode, RUNBACK, RUNUP and RUNDOWN, the load automatically sets to FORWARD and the target load is automatically effective. 6）Frequency correction The frequency correction circuit is used for inherent frequency modulation for grid frequency. The frequency correction is conducted by superimposing the corresponding unit load adjusted value that is obtained by calculating the deviation of the grid frequency through some dead bands on the target load. The circuit automatically disconnects under following conditions: a) Not at the coordinated control mode b) Invalid frequency deviation signal c) Unit under RUNBACK, RUNUP and RUNDOWN conditions 4.2.1.3 RUNBACK control 4.2.1.3 RUNBACK control （ Run Back ）means that the unit on load is greater than th e sustainable load of current RB
auxiliaries when essential auxiliaries of the unit are fault. At this time, RB is required to quickly conduct to reduce the load acceptable to current auxiliaries. The unit target load equal to the RB target value under the RB condition. In case that the unit target load is up to the RB target value, namely the unit allowable maximum output, the RB is completed. The AGC is cut off and the unit is changed from the coordinated control mode the turbine following boiler mode and it also can be manually reset. 1) RB adjustment: at the coordinated control mode, the RB is caused by following auxiliaries’ faults, comprising: a) Forced draft fan b) Induced draft fan 67
c) Primary air fan d) Coal pulverizer (two-layer and three-layer) e) Feed water pump 2）RB occurrence conditions: in case that the unit load is greater than the th e allowable maximum output of one of the forced draft fan, the induced draft fan and the primary air fan, the allowable maximum output of one of the feed water pumps under the situation that one set of feed water pump trips and the standby is not started in 5s and the allowable maximum output of the coal pulverizer in operation under the situation that one trips. The coal pulverizer-caused RB is different from the other one, the coal pulverizer-caused RB is classified as RB#2 and the other one is RB#1. The RB is completed when the actual unit load is less than the allowable maximum load of the unit or the RB also can be manually reset. 3）RUNBACK target value circuit formation When the RB happens, the target load automatically changes to the allowable maximum output of the device that causes this RB and then the RB rate takes effective. 4.2.1.4 Main steam pressure circuit setting In constant pressure operation, keep the main steam admission pressure invariable and change the unit power by regulating opening of the turbine control valve; In sliding pressure operation, the control valve is full opened or closes to full open and the unit power is changed by altering the steam admission pressure, namely the steam admission pressure is maintained by the boiler and the pressure is the function of the unit power that is changed with the power variation. The adoption of the sliding pressure operation is to change the thermal stress and deformation of the unit in condition-variable operation, so as to shorten the start and stop time of the unit, reduce throttling loss and power consumption of the feed water pump and improve the unit efficiency. The throttling loss refers to the loss of steam flowed through the control valve. The operating mode of the unit is classified as the constant and sliding pressure, with different main steam pressure set value under different operating mode. 4.2.1.5 Boiler main control 1) Boiler main control M/A: the boiler command used for presetting the total fuel quantity value synchronously functions to the main fuel control and air flow control circuits. In case that the boiler main control is not automatic, it outputs a trace command for current total fuel quantity. 2）Boiler main control and manual control switching con ditions: a) Bad actual power measuring point quality (take effect merely under the coordinated control mode) b) Bad main steam pressure measuring point quality c) Bad governing stage pressure measuring point quality 68
d) Bad steam drum pressure measuring point quality e) Big deviation between the main steam pressure and the set value f) Furnace draft under manual control g) All fuel under manual control h) Out fire MFT i) UNBACK 4.2.1.6 Turbine main control 1)
Turbine follow control mode (TF): the boiler main main control is manual. The main steam
pressure is changed by regulating opening of the turbine control valve. 2)
Coordinated control mode: both the boiler and the turbine main control modes in operation
are called as turbine-boiler coordinated control mode. 3) Turbine main control M/A: Turbine main control and manual control switching conditions: a) Bad actual power measuring point quality b) Bad main steam pressure measuring point quality c) Unallowable DEH remote control d) DEH out of remote control 4.2.1.7 Allowable cut-off conditions of DEH remote control 1）Manual cut-off 2）Bad load reference measuring point quality 3）Large deviation between the turbine main control output and the load reference value 4）Large deviation between the load command and the actual power 5）Large deviation between the main steam pressure set value and the measuring value Allowable DEH remote control can be sent out by a DEH remote control request button in case that the aforesaid conditions are totally met.
4.2.2 Steam drum water level control 4.2.2.1 As the unit starts on low load, a set of motor-driven pump is put into operation and the water level of the steam drum is controlled by a feed water bypass control valve. A main feed water valve is opened as the opening of the bypass valve is above 75% and the main steam reaches the required flow. After the main feed water valve is full opened, the water level of the steam drum is controlled by governing the rotating speed of the motor-driven pump. With the load rise, the turbo-feed water pump starts. It first operates in parallel with the motor-driven pump, and then gradually replaces the motor-driven pump to bear the load. 4.2.2.2 Single impulse control is used when the unit load is less than 25%; otherwise three-element control is applied. Water level of the steam drum is controlled by governing the rotating speed of the turbo-feed water pump and the motor-driven pump is used to standby after the unit load is greater than 25%. 4.2.2.3 Feed pump manual 1) Manual switching conditions of th e motor-driven feed pump 69
a) Invalid steam drum water level signal b) Big deviation between the set valve of the steam drum water level and the measuring value c) Big deviation between the scoop pipe control command of the feed pump and the feedback d) Bad scoop pipe position feedback quality e) Feed pump out of service f) The turbo-feed water pump in au tomatic operation 2) Manual switching conditions of the turbo-feed water pump control a) Invalid steam drum water level signal b) Big deviation between the set valve of the steam drum water level and the measuring value c) Invalid feed water flow signal d) Poor main steam flow signal quality e) Big deviation of MEH（microcomputer electro-hydraulic）control command and feedback f) The steam turbine for feed wate r pump trip g) MEH control h) The motor-driven feed pump in auto matic operation 3）Lockout load increase, reduction and rundown After the output commands of the feed water pump p ump in operation are totally out of tolerance, the lockout load increases. Further deterioration and the water level of the steam drum lower than the set value, rundown occurs. In case that the output commands of the feed pump in operation totally exceed the lower limit, the lockout load reduces.
4.2.3 Feed pump minimum flow control 4.2.3.1 In order to prevent cavitation, the re-circulating valve of the feed pump is used for controlling the inlet flow of the feed pump not lower than tha n the allowable minimum flow. 4.2.3.2 Full open the re-circulating valve in case of the inlet flow of the feed pump less than the alarm value 4.2.3.2 Manual switching conditions: 1) Big deviation of the valve command and the position feedback 2) Poor quality of the valve position feedback 3) Invalid inlet flow signal of the feed pump
4.2.4 Deaerator pressure control 4.2.4.1 Control of deaerator pressure control valve At the initial startup of the unit, the deaerator is in constant pressure operation maintained by its pressure control valve and its steam supply is from the auxiliary steam system. 2) While the deaerator steam supply is replaced with the fourth extraction steam supply with the load rise, it is put into sliding pressure operation and its control valve is gradually full closed. 3) When the unit trips in normal operation with the pressure drop rate in exceed of the set rate (0.05MPa/min）, the pressure control valve could be gradually opened to prevent from flash evaporation resulting from excessively fast pressure drop rate. 70
4) Full-closed pressure control valve for H-H deaerator pressure 5) Manual switching conditions: a) Invalid deaerator pressure signal b) Big deviation of the valve command and position feedback c) Poor quality of the valve position feedback
4.2.5 Deaerator water level control 4.2.5.1 Opening manual of the water control valves A (main control valve) and B (bypass control valve) is to control the deaerator water level. 4.2.5.2 The single impulse control is applied at the time of initial startup and low load stage of the unit and the three-element control is used in normal load operation of the unit. The feed water flow is used as a feed-forward signal under three-element control and the condensate flow is served as a process value of a three-element secondary controller. 4.2.5.3 The bypass valve is used as the output of the secondary control is within 30%; otherwise the main control valve is applied. 4.2.5.4 The bypass and main control valves are forced to be closed while the water level of the deaerator is high 2-value. 4.2.5.5 Manual switching conditions 1) Invalid deaerator water level signal 2) Big deviation of the deaerator water level and set value 3) Big deviation of the control valve command and the position feedback 4) Poor quality of the control valve position feedback
4.2.6 Deaerator water level control 4.2.6.1 A make-up water control valve on the make-up water pipe of the condenser is used for controlling the water level of it. 4.2.6.2 Manual conditions: 1) Invalid condenser water level signal 2) Big deviation of the set value and the measuring value 3) Big deviation of the control valve command and the position feedback 4) Poor quality of the control valve position feedback
4.2.7 Deaerator flash tank temperature control 4.2.7.1 Inside temperature of the flash tank in normal operation is regulated by the control valve. The bypass electric valve is opened to spray in case of the control valve fault or excessive inside temperature.
4.2.8 Condensate recirculation flow control 4.2.8.1 The condensate recirculation flow is controlled by regulating the condensate recirculation flow control valve. 4.2.8.2 Manual switching conditions: 1) Invalid condensate recirculation flow signal 71
2) Big deviation of the set value and the measuring value 3) Big deviation of the control valve command and the position feedback 4) Poor quality of the control valve position feedback
4.2.9 #1 HP heater water level control 4.2.9.1 The #1 HP heater water level in normal condition is controlled by regulating the opening of the #1 HP heater water level control valve (regulate the #1 HP heater drain water to flow into the #2 HP heater drain water well). When th e #1 HP heater water level is excessively high, it can be controlled by regulating the opening of the #1 HP heater emergency drain valve (make the #1 HP heater drain water flow into the drain flash tank). When the circuit is manually controlled, the water level is set to actual trace value. After it is automatic, the water level can be set by the operator. The set value of the controller of the #1 HP heater emergency drain valve is higher than forward-bias of the normal water level set value. 4.2.9.2 Full open the emergency drain valve in case of H-H #1 HP heater water level 4.2.9.3 Manual switching conditions of the water level control valve of the #1 HP heater 1) Invalid water level signal 2) Big deviation of the set value and the measuring value 3) Big deviation of the control valve command and the position feedback 4) Poor quality of the control valve position feedback 4.2.9.4 Manual switching conditions of the water level emergency drain valve of the #1 HP heater 1) Invalid water level signal 2) Big deviation of the control valve command and the position feedback 3) Poor quality of the control valve position feedback
4.2.10 #2 HP heater water level control 4.2.10.1 The #2 HP heater water level in normal condition is controlled by regulating the opening of the #1 HP heater water level control valve (regulate the #2 HP heater drain water to flow into the #3 HP heater drain water well). When th e #2 HP heater water level is excessively high, it can be controlled by regulating the opening of the #2 HP heater emergency drain valve (make the #2 HP heater drain water flow into the drain flash tank). 4.2.10.2 Full open the emergency drain valve in case of H-H #2 HP heater water level 4.2.10.3 Manual switching conditions of the water level control valve of the #2 HP heater 1）Invalid water level signal 2）Big deviation of the set value and the measuring value 3）Big deviation of the control valve command and the position feedback 4）Poor quality of the control valve position feedback 4.2.10.4 Manual switching conditions of th e water level emergency drain valve of the #2 HP heater 1）Invalid water level signal 2）Big deviation of the control valve command and the position feedback 72
3）Poor quality of the control valve position feedback
4.2.11 #3 HP heater water level control 4.2.11.1 4.2.11.1 The #3 HP heater water level in normal condition is controlled by regulating the opening of the #3 HP heater water level control valve (regulate the #3 HP heater drain water to flow into the deaerator). When the #3 HP heater water level is excessively high, it can be controlled by regulating the opening of the #3 HP heater emergency drain valve (make the #3 HP heater drain water flow into the drain flash tank). 4.2.11.2 Full open the emergency drain valve in case of H-H #3 HP heater water level 4.2.11.3 Manual switching conditions of the water level control valve of the #3 HP heater 1）Invalid water level signal 2）Big deviation of the set value and the measuring value 3）Big deviation of the control valve command and the position feedback 4）Poor quality of the control valve position feedback 4.2.11.4 Manual switching conditions of the water level emergency drain valve of the #3 HP heater 1）Invalid water level signal 2）Big deviation of the control valve command and the position feedback 3）Poor quality of the control valve position feedback
4.2.12 #5 LP heater water level control 4.2.12.1 The #5 LP heater water level in normal condition is controlled by regulating the opening of the #5 LP heater water level control valve (regulate the #5 LP heater drain water to flow into the #6 LP heater). When the #5 LP heater water level is excessively high, it can be controlled by regulating the opening of the #5 LP heater emergency drain valve (make the #5 LP heater drain water flow into the condensate tank). 4.2.12.2 Full open the emergency drain valve in case of H-H #5 LP heater water level 4.2.12.3 Manual switching conditions of the water level control valve of the #5 LP heater 1）Invalid water level signal 2）Big deviation of the set value and the measuring value 3）Big deviation of the control valve command and the position feedback 4）Poor quality of the control valve position feedback 4.2.12.4 Manual switching conditions of the #5 LP heater emergency drain valve 1）Invalid water level signal 2）Big deviation of the control valve command and the position feedback 3）Poor quality of the control valve position feedback
4.2.13 #6 LP heater water level control 4.2.13.1 The #6 LP heater water level in normal condition is controlled by regulating the opening of the #6 LP heater water level control valve (regulate the #6 LP heater drain water to flow into the #7 LP heater). When the #6 LP heater water level is excessively high, it can be controlled by regulating the opening of the #6 LP heater emergency drain valve (make the #6 LP heater drain 73
water flow into the condensate tank). 4.2.13.2 Full open the emergency drain valve in case of H-H #6 LP heater water level 4.2.13.3 Manual switching conditions of the water level control valve of the #6 LP heater 1）Invalid water level signal 2）Big deviation of the set value and the measuring value 3）Big deviation of the control valve command and the position feedback 4）Poor quality of the control valve position feedback 4.2.13.4 Manual switching conditions of the #6 LP heater emergency drain valve 1）Invalid water level signal 2）Big deviation of the control valve command and the position feedback 3）Poor quality of the control valve position feedback
4.2.14 #7 A/B LP heaters water level control 4.2.14.1 The #7 A/B LP heaters water level in normal condition is controlled by regulating the opening of the #7 A/B LP heaters water level control valve (regulate the #7 A/B LP heaters drain water to flow into the #8 A/B LP heaters). When the #7 A/B LP heaters water level is excessively high, it can be controlled by regulating the opening of the #7 A/B LP heaters emergency drain valve (make the #7 A/B LP heaters drain water flow into the condensate tank). 4.2.14.2 Full open the emergency drain valve in case of o f H-H #7 A/B LP heaters water level 4.2.14.3 Manual switching conditions of the water level control valve of the #7 A/B LP heaters 1）Invalid water level signal 2）Big deviation of the set value and the measuring value 3）Big deviation of the control valve command and the position feedback 4）Poor quality of the control valve position feedback 4.2.14.4 Manual switching conditions of the #7 A/B LP heaters emergency drain valve 1）Invalid water level signal 2）Big deviation of the control valve command and the position feedback 3）Poor quality of the control valve position feedback
4.2.15 #8 A/B LP heaters water level control 4.2.15.1 The #8 A/B LP heaters water level in normal condition is controlled by regulating the opening of the #8 A/B LP heaters water level control valve (regulate the #8 A/B LP heaters drain water to the condensate tank flow). When the #8 A/B LP heaters water level is excessively high, it can be controlled by regulating the opening of the #8 A/B LP heaters emergency drain valve (make the #8 A/B LP heaters drain water flow into th e condensate tank ). 4.2.15.2 Full open the emergency drain valve in case of H-H #8 A/B LP heaters water level 4.2.15.3 Manual switching conditions of the water level control valve of the #8 A/B LP heaters 1）Invalid water level signal 2）Big deviation of the set value and the measuring value 3）Big deviation of the control valve command and the position feedback 74
4）Poor quality of the control valve position feedback 4.2.15.4 Manual switching conditions of the #8 A/B LP heaters emergency drain valve 1）Invalid water level signal 2）Big deviation of the control valve command and the position feedback 3）Poor quality of the control valve position feedback 4.3 Turbine Digital Electro-hydraulic Control System (DEH)
4.3.1 Brief introduction of the DEH control system 4.3.1.1 The turbine control system, with two main functions of turbine rotating speed and load control, employs a digital electro-hydraulic control system of the Dongfang Electric Automatic Control Cooperation Limited consisting of a pure electric governing system an d a HP fire-resistant oil hydraulic servo system. 4.3.1.2 The HP and IP steam admission parts are totally provided with four HP control valves (CV), two IP control valves (ICV), two HP main stop valves (MSV) and two IP main stop valves (RSV). Six of the said ten valves are able to continuously control with the DEH microcomputer interface through servo valves; wherein one HP main stop valve (on right) employs a servo valve as a electro-hydraulic interface as well for the purpose of pre-warming. The other one HP main stop valve and two IP main stop valves realize two-position switch control with the DEH interface through a solenoid valve. 4.3.1.3 Pre-warming is conducted prior to steam admission under turning state when the IP cylinder is used for starting. The pre-warming is completed by leading auxiliary steam or re-cooled steam from the inlet of the HP cylinder exhaust check valve through a pre-warming valve. After the primary primary outlet outlet inwall inwall temperature temperature of the HP HP cylinder cylinder reaches reaches 150℃ , close the the cylinder cylinder to preserve preserve heat. Then pre-warm the HP main stop valves-casing and control valves-casing through opening the HP right main stop valve to some certain with the DEH. 4.3.2 DEH main functions 4.3.2.1 Turbine latched The conditions of all admission valves in full closing and turbine tripped already must be met before latching the steam turbine. After said conditions are all met, the turbine latched can be completed after the DEH outputs a boost command and the HP safety oil is in place. 4.3.2.2 Control prior to startup 1) Automatic thermal state judgment For the steam turbine and rotors, the startup procedure of the steam turbine is a heating process. In order to reduce the thermal stress during startup, different startup curves could be applied to different initial temperatures. The unit thermal states division accords with the HP inner casing wall temperature T at the governing stage of the steam turbine when HP starting.
75
Cold state
T<320℃
Warm state
320℃≤T<420℃
Hot state
420℃≤T<445℃
Extreme hot state
445℃≤T
The unit thermal states division automatically accords with the reheater inner casing wall temperature T when IP starting.
Cold state
T<305℃
Warm state
305℃≤T<420℃
Hot state
420℃≤T<490℃
Extreme hot state
490℃≤T
2) HP control valve casing pre-warming Pre-warming the HP control valve casing could be selected prior to the turbine rolling. When the pre-warming of the HP control valve casing is in operation, slightly open the right HP main stop valve could pre-warm four HP control valves at the same time. 3) Selection of startup modes Startup modes of the steam turbine include IP cylinder startup and HIP cylinder combined startup. DEH default mode is the IP cylinder startup. The HIP cylinder combined startup mode is merely used in case that the bypass system is failure or non-automatic. 4.3.2.3 Rotating speed control The DEH is speed closed-loop non-corresponding control before the synchronization of the steam turbine generator. Its set point is the set rotating speed. After the difference between the set rotating speed and the actual rotating speed is calculated by a PID controller through controlling the servomotor’s opening with the servo system, the actuate rotating speed can vary with the set rotating speed. The flow commands are derived from the calculation of the rotating speed controller. The opening commands of the control valves and IP control valves are generated by the flow curves distribution. While the IP control valves approximate to full open at the mode of HP cylinder startup, the rotating speed of the IP control valves is governed by the HP control valves. In case that tha t a HEAT SOAK operating mode and IP cylinder startup mode are selected and the unit rotating speed is less than 400r, the CV are slightly opened to pre-warm the HP cylinder. When the rotating speed is greater than 400r, the control valves’ opening is invariable and the ICV are opened. If the HEAT SOAL operating mode is not selected, the HP control valves are not opened with only the IP control valves in open state. After a target rotating speed is set, the given rotating speed automatically approaches to the target rotating speed with a set acceleration rate. When given rotating speed reaches the critical speed zone, its acceleration rate automatically alters to 300r/min/min (if the operator sets a acceleration rate greater than 300r/min/min, this one is served as the benchmark). 76
During speed rising, the steam turbine is necessary for medium-high speed warming, so as to reduce thermal stress. 1) Target Target rotating speed: the operator can set the target rotating speed by the butto n on the OIS. The rotating speed includes three shifts, namely 200, 1500 and 3000. Besides the operator, the DEH can automatically set the target value under following conditions: The target rotating speed is current speed while the steam turbine latches. The target rotating speed is 3000r/min while t he oil switch is disconnected. The target rotating speed is zero in case that the steam turbine has tripped already. The target rotating speed is to be changed to 3060r/min or 3300r/min when it exceeds the upper limit. The target rotating speed is set in accordance with the thermal stress control in self-startup mode. If the target rotating speed is set within the critical speed zone by error, alter it to the lower limit. Current combined critical set speed is set as follows (it can be modified according to actual conditions): 910r/min～1113 r/min The first stage: 910r/min ～1113 1113 r/min 1541r/min～1946 r/min The second stage: 1541r/min～1946 r/min 2) Acceleration rate: the operator can set the acceleration rate within 0r/min/min～500r/min/min. Under the condition that the operator has not set, the acceleration rates at cold startup and warm startup are 100r/min/min and 150r/min/min, respectively, hot startup and extreme hot startup are 300r/min/min. Under the self-driving mode, it is selected by the ATR software. Within the combined critical speed, it is 300r/min/min. After the selection of the target rotating speed and the acceleration rate, the unit begins to raise speed. If certain rotating speed needs to be maintained in the process of speed rising, press the HOLD button; in case that it reaches the critical speed zone, the button HOLD is ineffective, and so the unit automatically rolls through the zone. 3) Friction check（FRIC CHK）: When the actual rotating speed reaches 200r/min, press a FRIC CHK button by the DEH to close all valves. When the rotating speed of the steam turbine gradually drops, check the friction. After the friction check is completed, set the corresponding acceleration rate and target rotating speed to raise the unit speed again. 4）Warm-up: The warm-up speed of the steam turbine is usually set to 1500r/min and 3000r/min, and so the target value is usually 1500r/min and 3000r/min. After reaching the target rotating speed, it can be automatically stopped to warm up. If it needs to stop rising in the process of speed-raising, operate as follows: The operator sends a HOLD command while it is not at the ATR ATR mode. In the critical speed zone, the HOLD command is invalid, target speed modification is the only way. 77
5）3000r/min constant rotating speed: While the rotating speed of the steam turbine is stabilized above 3000 minus or plus 2r/min, the check prior to the synchronization for each system is conducted. For checking reliability and manual correctively of an automatic synchronization system, the generator is conducted a false synchronization test. During the test, an isolating switch of the generator grid side disconnects to send a false synchronization test signal. Similar to the condition in normal operation, the synchronization system alters the motor frequency and voltage with the DEH and the generator excitation system. While meeting the synchronous condition, the oil switch is connected. For the reason that the isolating switch is disconnected, the generator is actually not synchronous. Therefore, the DEH-received false synchronization test signal when the oil switch is connected is not regarded as generator synchronization during the test, so as to avoid speed rise resulting from synchronization and initial load. 6） Automatic synchronization: Before the unit synchronization, the steam turbine rotating rotating speed is automatically governed according to synchronization increase and reduction signals of a synchronization device while the DEH receives the “synchronization in operation” signal from the device. The oil switch can be connected on the premise of meeting all synchronous conditions. 4.3.2.4 Before the unit synchronization, the steam turbine rotating speed is automatically governed according to synchronization increase and reduction signals of a synchronization device while the DEH receives the “synchronization in operation” signal from the device. The oil switch can be connected on the premise of meeting all synchronous conditions. To avoid the occurrence of reverse-power, the DEH immediately increases the given value to enable the motor on 5% initial load. 4.3.2.5 4.3.2.5 Loa din g 1) For the inherent frequency modulation, the governing system of the SHE is provided with rotating speed feedback after the generator synchronization. While testing or operating on a base load, load control or main steam pressure control functions also can be taken effect. While the load control functions, both the target value and the set value are expressed in the form of MW. While the main steam pressure control functions, they are expressed in the form of MPa. In case that the said two functions are unavailable, they are expressed by the percentage of the total flow under rated pressure. After the target value is set, the set value automatically approaches to the target value with a set load rate, and then the generator load gradually increases. In the process of loading, pre-warming is required for the steam turbine to reduce thermal stress. 2）Target value: Besides the operator, ope rator, the DEH also can automatically set the target value under following conditions: While the load control function f unction is just put into operation, the target value is current load (MW). As the main steam pressure control function is put into operation, the target value is current main steam pressure (MPa). 78
While the generator is just synchronized, the target value is initial load set value (%). The target value is valve total flow command (%) at the manual state. While the said functions are stopped, the target value is valve total flow command (%). The target value equals to zero at the time of trip. The target value (%) is set by b y the CCS as the CCS is in operation. In case of excessive target value, value , it is 115% of the upper limit or 640MW. 3）Load rate: The load rate scope set by the operation is within 0MW/min ～100MW/min. Under the self-driving mode, the load rate is obtained according to the ATR. If the target value is expressed in form of percentage, the load rate is correspondingly expressed in percentage. 4）Warm-up: The steam turbine in the process of load is required to warm up for the reasons of thermal stress, differential expansion and so on. If temporary stopping is needed, operate as follow: The operator sends a HOLD command when the steam turbine is not at the CCS. Otherwise, the operator sends a HOLD command after exiting the CCS mode. 5）Constant pressure-sliding pressure-constant pressure loading: After the HP bypass valves are full closed, feed fuel to the boiler and maintain the HP control valves at 90% of the rated value. With the increase of the steam parameter, the load gradually increases. During sliding pressure loading, both the load control and the main steam control functions are not put into operation. If it is necessary for warming up, a combustion control system could be used for maintaining flaming so as to keep the load invariable; otherwise, the said two functions must be put into operation. At this time, the invariable load must be maintained by the function of throttling of the control valve. 4.3.2.6 Load control mode 1 ）Main steam pressure control (TPC): the main steam pressure controller is a PI regulator that is used for outputting a calculated control commands for the control valves and the ICV by comparing the set valve with the main steam pressure. In case that the coordinated control and steam pressure control under the turbine follow mode are required for the DEH system, the DEH system must be provided with a main stea m pressure control circuit. Controlling the opening of the control valves according to the deviation of the main stop valve inlet main steam pressure and the set value is able to keep the inlet pressure invariable in constant pressure operation and the unit power can be altered by controlling the opening of the control valves. The unit power variation in sliding pressure operation is realized by altering the inlet pressure when the turbine control valves are nearly full open or full open. That is the inlet pressure is maintained by the boiler. And the pressure is the function of the unit power and changes with the variation of the unit power. Operating conditions of the main steam pressure control: The control system in automatic mode Unavailable CCS control function The main steam pressure signal in no rmal condition 79
Unavailable TPC Unavailable inherent frequency modulation Unavailable load limit Disable conditions of the main steam pressure control function The main steam pressure control function to be stopped by the operator The main steam pressure signal failure The control system in manual operation Available TPC Available inherent frequency modulation Available load limit Oil switch to be disconnected Turbine trip The main steam pressure control and load control functions can not be put into operation at the same time. When the main steam pressure control functions, the set point is expressed in the form of MPa. While adopting the PID no-corresponding control, the actual main steam pressure equals to the set value at stable state. 2）Load control: The main steam pressure controller is a PI regulator that is used for outputting a calculated control commands for the control valves and the ICV by comparing the set valve with the main steam pressure. The operating conditions of the load control, comprising: The control system in automatic mode Unavailable CCS control function Normal power signal Unavailable load limit Unavailable TPC Unavailable inherent frequency modulation Disable conditions of the load control The load control function to be stopped by the operator Power signal failure Oil switch to be disconnected At the time of reaching the sliding pressure point Available TPC The control system in manual operation Available inherent frequency modulation Available load limit Load less than 30MW or greater than 600MW Turbine trip The main steam pressure control and load control functions can not be put into operation at the same time. When the load control functions, the set point is expressed in the form of MW. While 80
adopting the PID no-corresponding control, the actual load equals to the set value at the stable state. 3 ）Inherent frequency modulation: In order to guarantee the stability of the grid and the electricity supply quality, the inherent frequency modulation usually could be put into operation when the turbine generating set is in synchronous operation. When the unit rotating speed is within the dead zone, the frequency manual is set to zero and the inherent frequency modulation is unavailable. Otherwise, the inherent frequency modulation is available and the frequency manual set value is varied with the rotating speed based on a manual. The manual is adjustable within 3%-6%, primarily 5%. The dead zone is adjustable within 0r/min～30r/min and set to 4.5r/min. The dead zone range: 3000r/min minus or plus dead zone value. The operating conditions of the inherent frequency modulation: The control system in automatic operation and no rotating speed circuit failure After the load is firstly greater than 10% of the rated load 4）CCS control: in case that the CCS control is put into operation, the valves general commands of the steam turbine are controlled by the boiler control system, the DEH target load is set by the CCS set signal and the inherent frequency modulation dead zone is changed to 30r/min. The operating conditions of the CCS control function comprise: The control system in automatic operation already The unit to be synchronized already The CCS request signal to be b e received already and its command signal in normal condition Unavailable TPC Unavailable inherent frequency modulation Disable conditions of the CCS control function Available TPC Available inherent frequency modulation Available load limit The control system in manual operation No CCS request signal or CCS command signal failure Oil switch to be disconnected 5）Main steam pressure limit (TPC): in case that the boiler system is unable to maintain the main steam pressure for some failures, turning down the opening of the control valves to reduce the steam flow can be used for putting back the main steam pressure. The operating conditions of the main steam pressure limit: The steam turbine to be synchronized already The main steam pressure signal in normal condition The control system in automatic operation Disable conditions of the main steam pressure control Oil switch to be disconnected 81
The main steam pressure signal failure The control system changed into manual mode If the main steam pressure is less than the set limit value during the period of the main steam pressure limit function in operation, the main steam pressure limit functions. In operation, the set point reduces with 1%/s change rate based on the change rate of the early period. The target value and the set point equal to t he total valves position reference value and they reduce with the reference value. If the main steam pressure rises above the limit value, stop the set point. If the main steam pressure keeps invariable, stop reducing the actual load while it drops to a given value. While the main steam pressure limit is in operation, the load control and main steam control functions are automatically unavailable and the CCS control function is out of service as well. 6）High load limit: in case that the steam turbine generating set is inclined to operate on a load not high during a period, the operator is able to set a high load limit value within a scope ranging from 570MW to 640MW, so as to keep the actual load less than the value corresponding to the limit value all the time. 7）Low load limit: in case that the steam turbine generating set is inclined to operate on a load not very low during a period, the operator is able to set a low load limit value within a scope ranging from 0MW to 60MW, so as to keep the actual load greater than the value corresponding to the limit value all the time. 8）Valve-position Valve-position limit: in case that the steam turbine generating set is inclined to operate with a small valves opening for some reasons during a period, the operator is able to set a valve position limit value within the range from 0% to 120%. The DEH total valve position set value is a much small value between the load reference value and the limit value. In order to prevent the valve position from jumping, the valve position limit value is limited by the change rate, namely 1%/s. 4.3.2.7 Over-speed limit 1) Load rejection: when the unit rejects load greater than or equal to 15% and less than or equal to 40% of the rated load, a DEH acceleration relay acts to fast close the IP control valve and the target and set rotating speeds are changed to 3000r/min at the same time. After a time, the servo valve recoveries control for the IP control valve. At last the turbine rotating speed is stabilized at 3000r/min, so as to avoid fast synchronization after removing the accident. When the unit rejects load greater than or equal to 40% of the rated load, a DEH power-load unbalance relay acts to fast close the HP control valve and the IP control valve and to enable the target and set rotating speeds to be changed to 3000r/min. After a time, the servo valve recoveries control for the HP control valve. At last the turbine rotating speed is stabilized at 3000r/min, so as to avoid fast synchronization after removing the accident. 2) Acceleration control (ACC): when the turbine rotating speed is greater than 3060r/min and 82
acceleration is greater than 49r/min/s, an acceleration control circuit acts to fast close the IP control valve and restrict the maximum momentary speed of the steam turbine. 3) Power-load unbalance (PLU): Unbalance of the steam turbine power (with the use of reheat steam pressure characterization) and the steam turbine load (with the use of generator load characterization) will lead to steam turbine over-speed. When the deviation of the reheat steam pressure and the generator load exceeds the set value, the power-load unbalance relay acts to fast close the HP and IP control valves so as to restrict the turbine maximum momentary speed. 4) 103% over-speed (OPC): Under the condition that an over-speed test key switch is at normal position, once the rotating speed in excess of 103%, an over-speed limit solenoid valve quickly acts to close the HP and IP control valves and the servomotors are totally in outage. When the rotating speed is less than 103% of the rated speed, the solenoid valve loses electricity and the servo valves recoveries control for the control valves. 4.3.2.8 Over-speed protection For safety and reliability, the system is equipped with multiple over-speed protection, including DEH electric over-speed protection 110%, emergency trip eccentric ring mechanical over-speed protection 110%-11 110%-111%, operator manual stop and trip signal from the ETS (emergency trip system). 4.3.2.9 Online test: it comprises emergency governor eccentric ring oil spray test, DEH electric over-speed test, mechanical over-speed test, valve mobility test, main trip solenoid valve test and valve tightness test. 4.3.2.10 Switch-over between the DEH automatic/manual modes: the turbine control modes include the manual and a utomatic modes. If there are some faults occurred for the automatic mode, the steam turbine will automatically switch to the manual mode. Exit the automatic mode under following conditions: Turbine manual button to be operated The valve leak test The rotating speed is less than 2980r/min at the time of synchronizing. Auto Au to mati ma tic c mode mo de is al lowa lo wa ble bl e fo r op er atin at in g in case ca se th at th ere er e are ar e no t ab ove ov e sa id conditions happed and the valve position limit does not act. 4.3.2.11 Changeover between the DEH automatic/manual modes 1) The turbine control includes the automatic and manual control modes. 2) If there is part of failure for the automatic control mode, replace it with the manual control mode. Exit the automatic control mode under following conditions: a) Turbine manual button to be operated b) The valve leak test c) The rotating speed is less than 2980r/min at the time of synchronizing. Auto Au to mati ma tic c mode mo de is al lowa lo wa ble bl e fo r op er atin at in g in case ca se th at th ere er e are ar e no t ab ove ov e sa id conditions happed and the valve position limit does not act. 83
5. Main Test of the Unit 5.1 Static Test Test of the Control System 5.1.1 Testing conditions: 5.1.1.1 After overhaul and minor overhaul of the steam turbine； 5.1.1.2 after overhaul of the control system； 5.1.2 Test purposes: check flexibility of the control system and corresponding relation of the control signal and the valve stroke characteristic and check whether the valve stroke characteristic meets the requirement. 5.1.3 Test requirement 5.1.3.1 The test could be made after the boiler relieves all pressure and water stored up in the main and reheat steam pipes exhausts. 5.1.3.2 Thermal technician is in main charge of the test in the cooperation cooperat ion of the operator. 5.1.3.3 The static state action of the control system must be reliable and flexible. The corresponding relation of the control signal and the valve stroke must meet the requirement. 5.1.4 Test procedures: 5.1.4.1 Check that the DEH control system has put into operation and it is in normal operation; 5.1.4.2 Check the outage stage of the bypass system and make sure the HP and LP bypass relief valves are closed; 5.1.4.3 Put the lube oil system and the EH oil system into operation and make sure they are normal; 5.1.4.4 Output a mandatory tripped protection signal by the thermal technician and make sure the DEH has no alarm signal sent out; 5.1.4.5 Press a LATCH button on the DEH AUTO CONTROL screen, check the safety oil of the mainframe and make sure it is in place, make sure the RSVL and RSVR IP main stop valves are full open, and then click RUN. 5.1.4.6 Set the manual valve positions on the DEH MANUAL CONTROL screen, set the opening of the HP and IP control valves to 10％,30％,50％,80％ and 100％, respectively, check and make sure the opening displayed on the CRT accords with the actual opening, and the operation of every valve is flexible without jam; 5.1.4.7 Manually trip after the completion of the test; 5.1.4.8 Contact the thermal technician and restore the released signals. 5.2 Manual Trip Test 5.2.1 Testing conditions: 5.2.1.1 before cold startup of the unit; 5.2.1.2 after overhaul of the governing and control system; 84
5.2.2 Test purposes: check the flexibility of the emergency governor and emergency trip lever, the reliability of action of the e mergency governor. 5.2.3 Causes: 5.2.3.1 The test before starting could be made after the boiler relieves all pressure and water stored up in the main and reheat steam pipes exhausts; 5.2.3.2 Remote and local trip operations must be performed separately in this test under normal action condition. 5.2.4 Procedures: 5.2.4.1 Check the DEH, i.e. make sure it is normally put into operation and is in normal operation; 5.2.4.2 Check the bypass system, the HP and LP bypass valves, i.e. make sure the bypass system is in outage and the valves are closed. 5.2.4.3 Put the lubricating oil system and the EH oil system into operation and check for their normality; 5.2.4.4 Unblock the closed trip signals by the thermal technician and make sure the signals disappear; 5.2.4.5 Open the HP and IP main stop valves and the control valves in case of the steam turbine latches; 5.2.4.6 Press the emergency shutdown button and put the local manual trip handle to the trip position once separately in the central control room; make sure the HP and IP main stop valves and the HP and IP control valves fast close (It must be ensured that the closing time of the main stop valve and the control valves meets the required standards at the time of the initial startup after the unit installation or startup after the overhaul of the control system); 5.2.4.7 Restore the signals after the completion of the test. 5.3 Trip Protection Test Test of Turbine Emergency Trip System (ETS) 5.3.1 Testing conditions: 5.3.1.1 After overhaul and minor repair of the unit; 5.3.1.2 After the overhaul of some parts of the protection system or the modification of the protection set value; 5.3.1.3 Cold startup of the unit 5.3.2 Purposes: check the ETS trip circuits and make sure they are normal; check the protection action for correction, so as to improve the operating safety of the unit. 5.3.3 Requirements 5.3.3.1 The test could be made after the boiler relieves all pressure and water stored up in the main and reheat steam pipes exhausts; 5.3.3.2 Thermal technician is in main charge of the test in the cooperation cooperat ion of the operator. 5.3.4 Procedures 5.3.4.1 Check the DEH, i.e. make sure it is normally put into operation and is in normal operation; 85
5.3.4.2 Check the bypass system, the HP and LP bypass valves, i.e. make sure the bypass system is in outage and the valves are closed. 5.3.4.3 Put the lubricating oil system and the EH oil system into operation and check for their normality; 5.3.4.4 Unblock the closed trip signals by the thermal technician and make sure the signals disappear; 5.3.4.5 Press a LATCH button on the DEH AUTO CONTROL screen; open the HP and IP main stop valves and the control valves; 5.3.4.6 Make a test one by one for following trip signals and make sure the steam turbine trips by the thermal technician: 1) Low mainframe lube oil pressure (less than or equal to 69kPa) 2) Low EH oil pressure (less than or equal to 7.8MPa) 3) High A or B exhaust exhaust temperatur temperature e of the LP cylinder cylinder (greater (greater than than or equal equal to 107℃ ) 4) HP cylinder exhaust (inner wall) metal temperature greater than or equal to 432 4 32℃ 5) LP cylinder exhaust metal temperature greater than or equal to 107℃ 6) Low condensers A/B vacuum (greater than
kPa)
7) Low-low main stop valve inlet steam temperature and shut-down under the action of the protection 8) 3s delay in case that any one of the journal bearings vibrates up to 0.250mm and any one of the rest bearings vibrates up to 0.125mm; 0.08mm vibration of the bearing caps 9) #1-#6 #1-#6 bearings bearings metal metal temperatur temperature e of the generati generating ng set greater greater than than or equal equal to 115 115℃ and #7-#9 bearings bearings metal metal temperatu temperature re greater greater than than or equal equal to to 115 115℃ with 2s delay delay 10) HIP pressure differential expansion greater than or equal to 11.6mm or less than or equal to -6.6mm; LP differential expansion greater than or equal to 30mm less than or equal e qual to -8mm 11) Mainframe axial displacement greater than or equal to 1.2mm or less than or equal to -1.65mm 12) Turbine supervisory instrument action greater than 3300r/min 13) Low-low generator stator cooling water inflow rate 14）Low-low generator stator cooling water inflow pressure 15）High generator stator outlet cooling water 16) DEH major failure 17) Generator trip 18) Main fuel trip (MFT) of the boiler 19) Manual shut-down 5.3.4.7 Restore all signals after the completion of the test 5.4 Turbine Main Trip Solenoid Valve Test 5.4.1 Testing conditions: 86
5.4.1.1 Initial startup of the unit or after the overhaul and minor repair of the unit; 5.4.1.2 after the overhaul of the emergency governing system; 5.4.1.3 Make the test weekly in normal operation. 5.4.2 Purposes: Check whether its control circuit and action are normal and flexible, so as to ensure the unit can fast trip the steam turbine under the action of the ETS protection. 5.4.3 Test methods 5.4.3.1 Make sure that the testing conditions are met, indicating lamps associated with the test indicate correctly and the main trip solenoid valves 5YV, 6YV, 7YV and 8YV are live on the DEH SOLENOIDS TEST screen; 5.4.3.2 Press the 5YV TEST key on the SOLENOIDS TEST screen; check whether the 5YV turns red for electricity loss; locally listen to the solenoid valves and make sure they are acting; check whether the PS4 turns red. The color of t he PS4 disappears after the completion of the test. Green means that the test is successful and red means failure of the test. 5.4.3.3 Select NORMAL in TEST/NORMAL of the 5YV TEST dialog box; when the colors of the 5YV and PS4 get ring, it means that the test is completed. 5.4.3.4 Do not allow to continue to test in case of 5YV test failure. 5.4.3.5 Perform the 7YV, 6YV and 8YV tests according to a bove said methods and procedures. p rocedures. 5.4.3.6 Make sure all lamps are off after the completion of the test. te st. 5.4.3.7 Cautions: 1) First perform the 5YV and 7YV trip solenoid valves test and then the 6YV and 8YV; 2) Strictly forbid alternately performing the 5YV, 7YV, 7YV, 6YV and 8YV tests; 3) Perform the 6YV and 8YV tests after confirming the 5YV and 7YV tests are qualified; 4) The thermal technical and relevant operator must be present at the time of test; 5) The person specialized for operation and monitoring is required. 6) The testing conditions must be met in first. 5.4.3.7 All signals must be restored after the completion of the test prior to the startup of the unit. 5.5 Power-load Unbalance Relay (PLU) Loop Test Test 5.6 Eccentric Ring Oil Spray Test Test of Emergency G overnor 5.6.1 Testing conditions: 5.6.1.1 before the unit over-speed test; 5.6.1.2 after the overhaul of the emergency governing system; 5.6.1.3 Purposes: move about the eccentric ring to ensure that it is not locked and it can trip the steam turbine when the unit speed exceeds 110%～ 111% of the rated speed. 5.6.3 Oil-spray test methods: 5.6.3.1 Check the steam turbine, i.e. make sure it is in stable operation at 3000r/min; 5.6.2.2 Make sure that the t he indicating lamps associated with the test on the DEH indicate correctly; 87
5.6.2.3 Make sure that the DEH is in automatic mode; 5.6.2.4 Click the SPRAY OIL TEST in the SPRAY OIL TEST screen, the TEST indicating lamp is on; 5.6.2.5 Check whether the insolating solenoid valve 4YV acts and then check the oil spray solenoid valve 2YV; in case that the oil sprays into the emergency governor, the eccentric ring knocks out and the ZS2 sends out signal; 5.6.2.6 And then the 2YV loses electricity. The 1YV automatically connects several minutes later. After latching, the 4YV loses electricity electricity again. The turbine mechanical trip system resets, the unit is in normal operation and the test is completed. 5.7 Emergency Governor Minimum Oil Spray Action Speed Test Test 5.7.1 Testing conditions 5.7.1.1 at the initial startup of the unit or after the overhaul and minor repair of the unit; 5.7.1.2 after the emergency governor parts to be checked 5.7.2 Purposes: Check whether the action speed of the emergency governor eccentric ring is qualified at the time of oil injection speed rise, so as to make sure the operating safety of the unit. (Notes: the actual over-speed trip action speed of the emergency governor is corresponding to the minimum oil spray action speed. For the 3000r/min rated sped of the steam turbine, in case that the minimum oil spray action speed is greater than 2880r/min, the speed should be governed less than 2700r/min at outage before synchronizing. 5.7.3 Methods 5.7.3.1 Raise the turbine speed to 2700r/min at cold startup state, and then hold it; 5.7.2.2 Confirm that all indicating lamps on the DEH indicate correctly; 5.7.2.3 Put the SPRAY OIL TEST to the ON position on the SPARY OIL TEST screen; when the ZS4 (4YV LOCKOUT) indicating lamp on t he DIGITAL SIGNAL SIGNAL screen is on, locally check whether the insolating valve of the emergency trip test is at the insolating position. 5.7.2.4 Modify the target rotating speed of the unit to 3000r/min; stop speed rise maintenance and then keep on accelerating; when the LATCHED in the TURBINE LATCHED dialog box on the AUTO CONTROL is altered to TRIPPED, the emergency governor eccentric ring acts, and then record the action speed at this time. 5.7.2.5 If the steam turbine trips at the rotating speed less than or equal to 2700r/min or greater than 2880r/min, shut down to overhaul and regulate the emergency governor. 5.7.2.6 Put the SPRAY OIL TEST on the SPARY OIL TES screen to OFF position. When the ZS4 (4YV LOCKOUT) indicating lamp on the DIGITAL SIGNAL screen is off and the ZS5 (4YVRESETED) is on, locally check the insolating valve and reset it. When the TRIPPED in the TURBINE LATCHED dialog box on the AUTO CONTROL screen is altered into LATCHED, the emergency governor resets. 5.7.2.7 After the said procedures are completed, the turbine mechanical trip system resets and the 88
unit is in normal operation. 5.7.2.8 It must be confirmed that the insolating valve 4YV is closed and reverent signals indicate correctly in test; otherwise, the unit is to trip. 5.8 Turbine Mechanical Over-speed Test Test 5.8.1 Testing conditions 5.8.1.1 Initial startup after the steam tu rbine assembly 5.8.1.2 after the overhaul of the unit; 5.8.1.3 after reassembly of the e mergency governor; 5.8.1.4 After overhauling the set valve in the front box that affects on the action speed of the emergency governor; 5.8.1.5 Before making the load rejection test 5.8.2 Purposes: Check the eccentric ring fo r flexibility and the action speed for correction, so as to ensure the safe operation. 5.8.3 Testing conditions: 5.8.3.1 The over-sped test must be in charge of the general engineer and under the direction of associated technicians. 5.8.3.2 The test must be performed and monitored by special person. 5.8.3.3 The test must be made after the tests of the HIP main stop valves and control valves, centralized manual trip shut-down, local manual trip and emergency governor oil spray, leakage and turbine supervisory instruments are completed and qualified. 5.8.3.4 The over-speed test during the cold startup of the unit should be made under the condition that the unit operates for 3-4h with the load greater than or equal to 150MW. 5.8.3.5 The test must be performed when the unit has operated for 2s after the unit oil spray test; otherwise it is to affect the action speed of the emergency governor. If the regular oil-spray test had performed and the emergency governor did not disassembled or regulated, merely the over-speed test is required and it is unnecessary for making the oil spray test. 5.8.3.6 During the test, the local manual trip handle and the centralized emergency shut-down trip button must be in charge of special person. They must communicate well and a speed indicator must be provided at the front box. 5.8.3.7 During the test, it must closely monitor the rotating speed, vibration, axial displacement, LP cylinder exhaust temperature and so on, and put associated recorders and printers into operation to continuously type the said parameters. 5.8.3.8 The main and reheat steam pressure must meet the requirement of the corresponding startup curves, and the main and reheat steam temperature should be stable and matched with the turbine metal temperature. The main steam pressure should be ranged from 5MPa to 6MPa; the main steam temperature should be above 350℃～400℃; the the IP cylind cylinder er admiss admission ion pressu pressur r e should be maintained at 0.1MPa～0.2MPa through the HLP bypass; The reheat temperature 89
should should be rang ranged ed from from 300℃ to 350 350℃ . The The cond condens enser er vacu vacuum um and and exha exhaust ust temper temperatu ature re must must be normal; otherwise, a cooling water spray device must be put into operation. 5.8.3.9 Modify the DEH and the TSI protection action value to 3330 r/min; 5.8.4 Test procedures: 5.8.4.1 Load down according to normal stop procedure; 5.8.4.2 Start the TOP and MSP and make sure they are in normal o peration; 5.8.4.3 The HLP bypass at the follow mode; 5.8.4.4 Latch again to keep the rotating speed at 3000r/min after the remote and local manual trip tests is separately performed and qualified; 5.8.4.5 Confirm that the indicating lamps on the DEH associated with t he tests indicate correctly; 5.8.4.6 Check whether the testing conditions on the DEH CONTROL screen are met; 5.8.4.7 Press the MECH OSP TEST button to put it at the ON position after accessing the OVERSPEED TEST screen; 5.8.4.8 Set the target rotating speed at 3340 r/min; 5.8.4.9 Press a GO button to begin rising speed; beginning from the speed of 3000 r/min at the rate of 300r/min/min, the speed accelerates to 108% of the rated speed, namely 3240 r/min; and then its rate is changed to 100r/min/min and it slowly raises to the eccentric ring action speed. The DEH records the trip rotating speed and displays it on the OIS screen. If the unit does not act as its speed is up to 3330r/min, it means that the mechanical trip is failed and the electric over-speed protection functions. Check whether the HIP main stop valves, control valves, every extraction check valves, HP cylinder exhaust check valves are fast closed, and the emergency dump valve (BDV) is opened; record current action speed. 5.8.4.10 in case that the electric over-speed protection does not function as the speed of the steam turbine rises to its action value, manually stop immediately. immediately. 5.8.4.11 the emergency governor over-speed test should be made twice under the same situation and difference of the action speed during twice tests should not exceed 18r/min. 5.8.4.12 The MECH OSP TEST button automatically switches to the OFF position after the completion of the test. 5.8.4.13 reset the electric over-speed protection set value to 3300 r/min after the completion of the test. 5.8.4.14 the test must be completed in 30min. 5.8.5 Cautions: 5.8.5.1 Dwell time at the high speed zone with the speed of 3200r/min should not exceed 1min. 5.8.5.2 in case that the emergency governor does not act when the speed is up to 3330 r/min, immediately trip. The test should be continuous after finding out the causes and taking the right measures. 5.8.5.3 The unit is prepared for stopping after a long-term operation. In case that its operating condition is unclear, it strictly forbids making the over-speed test. 90
5.8.5.4 Prohibit performing the over-speed test prior to the overhaul; 5.8.5.5 Prohibit performing the test at the rated parameter or approximate to the rated parameter; 5.8.5.6 Prohibit performing the test under following conditions: jammed emergency governing system, control valves, main stop valves, extraction check valves; unqualified tightness of the control valves, main stop valves and the extraction check valves; the unit bearing vibration out of limits and the unit in abnormal operation. 5.8.5.7 The bearing oil inlet temperature should be maintained within normal range during the test. 5.9 Electric Over-speed Test Test of Steam Turbine 5.9.1 Testing conditions: 5.9.1.1 Initial startup after the steam tu rbine assembly 5.9.1.2 after the overhaul of the unit; 5.9.1.3 after reassembly of the e mergency governor; 5.9.1.4 After overhauling the set valve in the front box that affects on the action speed of the emergency governor; 5.9.1.5 Before making the load rejection test 5.9.2 Purposes: Check whether the electric over-speed protection is normal and the action speed is qualified, so as to ensure the safe operation. 5.9.3 Testing conditions: 5.9.3.1 The over-sped test must be in charge of the general engineer and under the direction of associated technicians. 5.9.3.2 The test must be made after the tests of the HIP main stop valves and control valves, centralized manual emergency trip shut-down, local manual trip and valves leakage are completed and qualified. 5.9.3.3 The over-speed test during the cold startup of the unit should be made under the condition that the unit operates for 3-4h with the load of 150MW. 5.9.3.4 Enough testing personnel, testers and tools are required to prepare prior to the test. 5.9.3.5 During the test, the remote and local manual trip handles must be in charge of special personnel. A speed indicator should be provided at the front box. The centralized and local communication facilities are in good condition. 5.9.3.6 During the test, it must closely monitor the rotating speed, vibration, axial displacement, LP cylinder exhaust temperature and so on. 5.9.3.7 Before the test, put associated recorders and printers into operation to continuously type the said parameters. 5.9.3.8 The main and reheat steam pressure must meet the requirement of the corresponding startup curves, and the main and reheat steam temperature should be stable and matched with the turbine metal temperature. The main steam pressure should be ranged from 5MPa to 6MPa; the main steam temperature should be above 350℃～400℃; the the IP IP cyli cylinde nderr admi admissi ssion on pres pressur sure e 91
should be maintained at 0.1MPa～0.2MPa through the HLP bypass; The reheat temperature should should be range ranged d from from 300℃ to 350 350℃ . The The conde condenser nser vacuum vacuum and exhaust exhaust temper temperatu ature re must must be normal; otherwise, a cooling water spray device must be put into operation. 5.9.4 Test procedures: 5.9.4.1 OPC protection test 1）The OPC key test is performed before the unit startup. 2）Methods: a. Check the EH oil system, i.e. make sure it has put into operation and electrified; b. Click the LATCH button on the DEH AUTO CONTROL screen; make sure the mainframe safety oil is in place, the RSVL, RSVR IP main stop valves are full opened; check the MSVL and MSVR and make sure they are full open after clicking the RUN button; c. Manually open the HP and IP control valves; d. Switch the OPC changeover switch to the “TEST” position on the DEH manual operating panel; e. Check the HP and IP control valves i.e. make sure they are closed; f. Switching the OPC changeover switch to the "NORMAL” position, making sure the HP and IP control valves are opened, the test is completed. 3）OPC dynamic test a. The unit rolls to 3000 r/min. b. Check the OPC key switch i.e. makes sure it is at the NORMAL position; c. Set the target rotating speed as 3091 r/min, acceleration rate 50 r/min/min and then accelerate; d. The rotating speed displayed on the screen is greater than or equal to 103% when the rotating speed is up to 3090 r/min. e. Check that the HP and IP control valves, the HP and IP drain valves and the HP cylinder exhaust check valve are closed, the HP cylinder exhaust vent valve and the LP cylinder exhaust spray valve are opened; the rotating speed begins to slow down. f. When the rotating speed slows down below 3000r/min, check the HP and IP control valves i.e. make sure they are gradually opening and maintain the rotating speed at 3000r/min. 5.9.4.2 Electric over-speed protection test 1) Load down according to normal stop procedure; 2) Start the TOP and MSP and make sure they are in normal operation; 3) The HLP bypass at the follow mode; 4) Generator disconnection and the rotating speed to be maintained at 3000r/min; 5) Latch again to keep the rotating speed at 3000r/min after the remote and local manual trip tests is separately performed and qualified; 6) Confirm that the indicating lamps on th e DEH associated with the tests indicate correctly; 7) Press the ELEC OSP TEST button to put it at the ON position after accessing the OSP TEST 92
screen; 8) Modify the rotating speed as 3310r/min; 9) Send out GO command through the OIS; 10) Beginning from the speed of 3000 r/min at the rate of 300r/min/min, the speed accelerates to 108% of the rated speed; and then its rate is changed to 100r/min/min and it slowly rises to the eccentric ring action speed till 3300r/min to trip (or manual trip). The DEH records the trip rotating speed and displays it on the OIS screen. 11) The ELEC OSP TEST button automatically switched to the OFF position after the completion of the test. 5.10 Valves Activity Test 5.11 MSV and CV Leak Test 5.12 Mainframe Low Lube Oil Pressure Interlock Protection Test Test 5.12.1 Testing conditions: 5.12.1.1 before the initial startup after the unit reassembly or the overhaul and minor repair; 5.12.1.2 The lube oil of the mainframe or its control system to be overha uled; 5.12.1.3 Once a week in normal operation 5.12.2 Purposes: regularly check the standby state of the AC and DC lube oil pumps, so as to ensure they are in good condition and improve the safety of the unit in operation and accident. 5.12.3 Testing conditions: 5.12.3.1 The test prior to the unit startup can be realized by starting the pumps in the corporation of the thermal technician. 5.12.3.2 In normal case, the test should be made in stable operation of the unit. 5.12.4 Procedures: 5.12.4.1 Check the mainframe lubricating oil system i.e. makes sure it is in no rmal operation; 5.12.4.2 Slowly open the test valve of the AC auxiliary oil pump; 5.12.4.3 Check the AC auxiliary oil pump, i.e. make sure its startup, current and oil pressure are normal; 5.12.4.4 Close the test valve; 5.12.4.5 Remotely stop the AC auxiliary oil pump; 5.12.4.6 Check the mainframe lubricating oil system i.e. make sure it is normal; if the pressure of the system drops, immediately start the AC oil pump and report to associated leaders; 5.12.4.7 Make the low oil pressure startup test for the corresponding oil pumps with the test valves of the DC emergency oil pump and the startup oil pump; 5.12.4.8 Confirm that every test valve is at the anticlockwise bottom after the completion of the test; 93
5.12.4.9 Check the lubricating oil system, i.e. make sure it is in normal operation. 5.13 Vacuum Leakage Test 5.13.1 Testing conditions: 5.13.1.1 The test is applicable to the restarted unit after reassembly or overhaul. 5.13.1.2 In normal operation, the test is made once a month. 5.13.2 Purposes: Check whether the vacuum leakage is met the requirement, so as to process it immediately and improve the economical efficiency. efficiency. 5.13.3 Necessary conditions for the test: 5.13.3.1 The condenser pressure is normal and stable; 5.13.3.2 The load of the unit is stabilized at 80% of the rated load as performing the test; 5.13.3.3 The unit load and its operating parameters are stable during the test; 5.13.3.4 Before the test, the mainframe vacuum should be greater than negative 92KPa; otherwise, find out the causes and remove them; 5.13.3.5 The water circulating pump must be in MCR operation during testing. 5.13.4 Test methods: 5.13.4.1 Record the unit load, condenser vacuum and the LP cylinder exhaust temperature before the test; 5.13.4.2 Close the vacuum pump inlet manual insolating valve in operation at the HP and LP side of the condenser or full stop the vacuum process pump (Note: the stopped vacuum pump inlet pneumatic valve should be closed by interlock); 5.13.4.3 After the valve shut-down, continuously record the HP and LP condenser vacuum for 5min at once per minute and then seek its average value; 5.13.4.4 Open the vacuum process pump outlet manual isolating valve (or start the vacuum process pump); 5.13.4.5 Obtain the condition of the vacuum drop in every minute with the vacuum drop-out value in later 5min; 5.13.4.6 The test must be stopped in time and the vacuum system must be put into operation again in case that the condenser vacuum during the test drops to the alarm value or the exhaust temp temper erat atur ure e ris rises es to 50℃. （1mmHg/min）; 5.13.4.7 Standards of the condenser vacuum leakage test : excellent: 0.13KPa/min
good: 0.27KPa/min（2mmHg/min）; qualified: 0.4 KPa/min（3mmHg/min） 5.14 Extraction Check Valve Activity Test Test 5.15 Load Rejection Test Test 5.15.1
Purposes: 94
5.15.1.1 Measure the dynamic maximum momentary speed of the control system after the load rejection of the unit that should be less than the action value of the over-speed protection device. 5.15.1.2 The transition process of the rotating speed after the load rejection attenuates and the unit is in idle operation at the rotating speed of 3000r/min after oscillating several times. 5.15.1.3
Measure the dynamic process of the key link in the control system at the time of load
rejection; 5.15.1.4
Check the mainframe and associated facilitates for their adoptive capability to the load
rejection and mutual time relation, so as to provide data for improving the dynamic quality of the unit and analyzing the performances of the facilities. 5.15.2
Testing conditions:
5.15.2.1
Establish a commanding agency for the test with clear assignment of responsibilities
and duties and appoint a commander in chief for the unified command of the test; 5.15.2.2
Have a testing schedule that is approved by the department in charge and set jointly by
every party; 5.15.2.3
Every professional participant in the test must be provided with reliable communication
facility; 5.15.2.4
The testers must be full, reliably and soundly equipped.
5.15.2.5
The workers in charge of the operation should be well trained and has a clear
assignment for the responsibility and duty. 5.15.2.6
Completed and qualified tests
⑴
Every valve activity test of the steam turbine
⑵
Normally auto-switch between the two EH main oil pumps with 10.7-11.7MPa oil pressure,
32℃-54℃ oil temper temperature ature and and normal normal oil oil level; level; 8.0MPa 8.0MPa HP HP accumula accumulator tor nitrogen nitrogen-filled pressure ⑶
The action set value of the emergency governor accounting for 110%-111% of the rated
rotating speed meets the requirement. ⑷
The electric over-speed protection set value accounting for 110% of the rated rotating
speed meets the requirement. ⑸
The completion of totally closing time measurement of every main stop valve and control
valve at the time of latching meets the requirement. ⑹
The leakage test for every main stop valve and control valve meets the requirement.
⑺
The no-load test and on-load test are qualified; the system and mainframe, auxiliary of the
steam turbine are normally and flexibility operated without defect. Every supervisory instrument indicates correctly. correctly. ⑻
The fire-resistant oil and turbine oil quality of the emergency governing system are fully
qualified. ⑼
The turbine extraction regenerative system, steam bypass system and extraction check
valve are in normal operation and the protection interlock is reliable. ⑽
The local manual trip and remote control trip devices are flexible and reliable. 95
⑾
The unit bypass system is normal.
⑿
The temperately equipped devices such as the load rejection button (convenient for the
program control of the oscillograph, generator main oil switch and busbar switch and so on) are ready and qualified. ⒀
The indicators, recorders and instruments for the test are complete and in good condition.
5.15.2.7 ⑴
Cautions:
Operate the activity tester for preventing from jamming in the system prior to the test to
avoid the failure to operate on command; ⑵
Check the testing instruments and meters before the test to ensure they are complete and
sound; ⑶
Release these interlocks that hinders from testing before the test;
⑷
Regulate the operating conditions before the test to guarantee it is operating at the rated
parameter, vacuum and load, and full record the parameters including the rotating speed, pressure, displacement (stroke) and so on after it is stabilized; ⑸
Ensure fluent communication for the commanding system;
⑹
The command in chief orders to reject load based on the reports from the person in charge
of every project. ⑺
The oscillograph must be started in about 1s before the load rejection.
⑻
Closely monitor the conditions of the unit maximum momentary speed; Immediately trip
while the rotating speed is up to 3330r/min; ⑼
Closely monitor the conditions of every main stop valve, control valve and extraction check
valve; Take Take right measure in time in case of normal condition; ⑽
Closely monitor the conditions of the unit bearings to ensure safe operation;
⑾
The parameters including the rotating speed, pressure and displacement (stroke) and so on
recorded during the test must contain the maximum and minimum values. ⑿
Full record the rotating speed, pressure and displacement (stroke) once after the rotating
speed is stabilized; ⒀
Restore the unit to operate in normal condition and every interlocks after the completion of
the test; ⒁
Sort the waveforms and hand-written records a nd compile the test reports in time.
5.15.2.8
Safety precautions
⑴
Test each item specified before th e load rejection and ensure the test data are qualified;
⑵
The safety measures taken in the over-speed test are totally suitable for the load rejection
test. ⑶
The operator must closely monitor the states of the unit and operate it corresponding to the
states after the load rejection. ⑷
The operation after the load rejection must be fast and accurate. After the steam turbine
rejects a rated load, the no-load operating time should be less 30min. 96
⑸
The digital tachometer provided by the manufacture must be in charge of an appointed
person. When the rotating speed reaches the reticle (3330r/min), it must quickly and decidedly trip. If the speed continues to rise or maintains, the emergency measures of closing the motor-driven main stop valve, each extraction check valve and breaking vacuum must be taken immediately. ⑹
The vibration values of every bearing must be monitored by a specially-appointed person.
The moment there is abnormal condition, the person must trip quickly to prevent from happen ing or wide spreading accident. ⑺
If the servomotors of the HP control valve or the IP control valve are kept starting after the
load rejection test, or the steam turbine is in single cylinder steam admission state resulting from the starting of them after restoring, the steam turbine must be stopped immediately. immediately. ⑻
The HP, IP and LP differential expansion must be monitored at the idle running and load
variation of the steam turbine. If there is abnormality occurred, take right measure immediately. immediately. ⑼ After the load rejection test, t he conditions of the turbine bypass system, the deaerator, the
condenser water level, the extraction regenerative system, the steam turbine and extraction system drain water, HP cylinder exhaust temperature rise, thrust bearing metal temperature, the cylinder metal temperature and so on must be noted. If there is any abnormity, take right measures immediately. immediately.
Chapter III Start-up and Outage of the Unit and Operating Maintenance Thereof 1 Start-up of the Unit 1.1 Start-up Specifications and Requirements 1.1.1 The unit startup after overhaul should be presided over by the chief engineer with the participation of the directors in charge of the generation and equipment departments, department heads and relevant personnel. 1.1.2 The startup after minor repair should be presided over by the chief engineer or the director in charge of the generation department with the participation of the director in charge of the equipment department, the department heads and relevant personnel. 1.1.3 The duty director assumes unified command and takes charge of the normal startup of the unit and the generation department heads are charge of on-site technical supervision and guidance. 1.1.4 Before overhaul and minor repair of the unit, check the relevant devices and system for their conditions and completion report of construction work and oil quality qualification report for completion. 1.1.5 Confirm that the overhaul of the unit is finished; the work-order cards are totally cancelled; 97
the site sanitary conforms to the standards; relevant temporary platform is removed and the cold test is acceptance. 1.1.6 Confirm that every mainframe and auxiliary interlock and protection test are completed and qualified; every valves commissioning are finished and locates at right position of their switches and part of the overhauled auxiliaries has a test run and operates normally. normally. 1.1.7 The thermal technicians prepares for the interlock and protection tests of relevant devices and system and then records the test well. 1.1.8 The tools, instruments, meters, various recorder chart paper and operation order for the startup has been ready and the arrangement for relevant person has been made. 1.1.9 All liquidometers are clean; every pressure gauge indicates right and the primary and secondary valves of the field measuring device are opened. 1.1.10 Confirm that the centralized control room, every filed control panel and cabinet are complete, every instruments, alarms, operation and control switches are sound and work well and all thermal instruments, signals and protection devices are power on. 1.1.11 1.1.11 Check the bearings of every rotating de vice, i.e. make sure the oil level is normal and the oil quality is qualified. 1.1.12 All motor-driven valves, control valves and control dampers are power on and the display is accordance with the actual condition. After the commissioning of the base type regulating device is completed and the set value is correct, put the device into automatic operation. 1.1.13 after confirming that the insulation of every electric device is qualified and the casing ground connection is complete, delivery power to the working position. 1.1.14 The control and supervisory systems of the DCS, DAS, FSSS, BMS, D-EHG, D-EHG, MEH,HITASS, TSI, PRP, ASS and bypass are in normal operation and the parameters on the CRT is correctly indicated. 1.1.15 Check the expansion indicators of the pipes and record their initial values. 1.1.16 the illumination of the plant building at ever place is good; the emergency illumination system is normal and it can be put into operation at any time. 1.1.17 Site fire control system is in normal operation and the fire fighting device is complete and sound. 1.2 Start-up Prohibition Conditions of the Unit 1.2.1 The assembly, overhaul and commission affecting on the startup is not completed or qualified. The work-order cards are not expired and taken back. And the equipment site is inconformity with the Safety Code for Electric Industry. Industry. 1.2.2 Supervisory malfunction of main instrumentation of the unit affects the startup or normal operation of the unit. 1.2.3 Any one of the protection devices of the unit malfunction 1.2.4 Unqualified main interlock protection test of the unit 98
1.2.5 The malfunction of the regulating instrument and base type regulating instrument affects the startup or normal operation of the unit. 1.2.6 Instruments and protective power supply of the unit lose. 1.2.7 The upper and low cylinders metal temperature difference of the HP and the IP cylinders exce exceeds eds 35 35℃ and and the upp upper er and and low lower er out outer er cas casin ing g diff differ erenc ence e is great greater er tha than n 50℃ . 1.2.8 The HP and IP cylinders differential expansion greater than 10.3mm or less than negative 5.3mm; the LP cylinder differential expansion greater than 19 .8mm or less than negative 4.6mm; 1.2.9 The mainframe rotor eccentricity greater than 10% of the initial value 1.2.10 one of the HIP main stop valves, control valves, extraction check valves, HP cylinder exhaust check valves, V.V and BDV is locked and can n ot be tightly closed. 1.2.11 Any one of the main thermal interlock protection (mainframe, electric and boiler interlock, boiler MFT and steam turbine protection) or the generator transformer unit functions abno rmally. rmally. 1.2.12 Any one of the TTOP, MSP, EOP, EH oil pump, journal oil pump and the turning gear is failed or corresponding interlock test is unqualified. 1.2.13 There is clear metal fricative sound when turning and its current apparently increases or it vibrates by a wide margin. 1.2.14 The lube oil level of the oil tank and the EH oil tank lower than the limit value or unqualified oil qual quality ity and lube lube oil oil tempe temperat rature ure less less than than 27 27℃ ; 1.2.15 Unqualified steam and water quality; 1.2.16 Abnormal gland steam supply; 1.2.17 Unqualified emergency governor over-speed test of the mainframe; 1.2.18 Generator hydrogen-cooled system failure or unqualified hydrogen purity (less than 96%) and moisture; 1.2.19 Sealing oil system failure; 1.2.20 Non-conforming startup and protection of the unit resulting from the bypass system failure and abnormal BMS supervisory controller; 1.2.21 Abnormal governing system of the steam turbine so that no-load running can not be maintained and rotating speed can be not controlled below the action speed of the emergency governor after the load rejection; 1.2.22 Unqualified insulation of the primary power system of the generator transformer unit; 1.2.23 The generator voltage regulator in abnormal operation; 1.2.24 The generator synchronization system in abnormal operation; 1.2.25 Emergency diesel generating set failure; 1.2.26 The UPS and AC system has the fault with direct influence on safe operation of the unit after its startup. 1.2.27 The stator cooling water system of th e generator is failure or its water quality is unqualified. 1.2.28 The field double-colored water level indicator for the boiler drum is failed to operate. 1.2.29 The leakage test of the generator after the overhaul of the unit is unqualified. 99
1.3 Start-up State Classification of the Unit 1.3.1 The IP cylinder startup in normal operation is preferential. 1.3.1.1 IP cylinder startup (classified by inner cylinder inner wall metal temperature of the IP cylinder at the time of startup) 1）Cold Cold stat state: e: T is is les less s tha than n 305 305℃ ; 2）Warm arm sta state: te: T is is great greater er than than or or equ equal al to to 305 305℃ or less less than than 420 420℃ ; 3）Hot Hot sta state: te: T is grea greate terr tha than n or or equa equall to to 420 420℃ or less less than than 490℃ ; 4）Extrem Extreme e hot state: state: T is is less less than than or or equal equal to 490 490℃ . 1.3.1.2 HIP cylinder combination startup (classified according to the inner wall metal temperature T at the first stage of the steam turbine at the time of startup) 1）Cold Cold stat state: e: T is is les less s tha than n 320 320℃ ; 2）Warm arm sta state: te: T is is great greater er than than or or equ equal al to to 320 320℃ or less less than than 420 420℃ ; 3）Hot Hot sta state: te: T is grea greate terr tha than n or or equa equall to to 420 420℃ or less less than than 445℃ ; 4）Extrem Extreme e hot state: state: T is is less less than than or or equal equal to 445 445℃ . 1.4 Inspection befo re the Steam Turbine Start-up 1.4.1 Overall inspection and requirements of the unit 1.4.1.1 All professional maintenance is completed and all work-order cards having influence on the startup of the unit have expired in accordance with the relevant manual. 1.4.1.2 The stairs, rails and platforms are complete and sound, and t here are not any sundries that hinder operation and passing through around the passages and the devices. 1.4.1.3 All systems must be connected well; every man hole and inspection hole is closed and pipe supports are firm, complete and heat preserved. 1.4.1.4 The illumination of plant b uilding is good and emergency illumination system is normal. 1.4.1.5 The equipment name, rotating sense of the rotating mechanism and medium directional arrows of the pipes are complete and correct. 1.4.1.6 The communication system of plant building and tools, instruments and various record forms specified by the unit startup is ready and complete. 1.4.1.7 The plant water supply system is in normal operation; make-up water of the cooling tower is up to the normal level; the water circulating system is prepared for operating; the fire-extinguishing water system is in normal operation and the fire fighting device is complete. 1.4.1.8 Confirm that the centralized control room, every filed control panel and cabinet are complete, every instruments, alarms, operation and control switches are sound and work well and all thermal instruments, signals and protection devices are power on. 1.4.1.9 Confirm that every operational, protection, control, signal and instruments power supply is disconnected and normal; 1.4.1.10 Make sure the unit control system is operating normally; 100
1.4.1.11 Confirm that various oil and water systems meet the startup requirements; 1.4.1.12 Check the CRT display screen, signals and audible and viable signals, i.e. make sure they are normal and correct; 1.4.1.13 Put the valves in the systems at the required states according to the valve check cards; open every liquidometer isolating valve; check the primary and secondary valves of all thermal signals, i.e. make sure they are open; 1.4.1.14 Check every motor-driven actuating mechanism and auxiliary power supply, i.e. make sure they are power off and confirm the trial running is qualified; 1.4.1.15 Confirm that the trial run step by step and interlock protection tests of every system and auxiliary after the overhaul and minor repair of the unit are qualified; 1.4.1.16 Confirm that the remote states of every valve and rotating mechanism are corresponding to the local states and the two states can be well controlled. The changeover switch is put at the remote position; 1.4.1.17 Check and make sure the interlock and protection signals of all devices and systems have put into operation before the unit startup; 1.4.2 Inspection before thermal startup 1.4.2.1 Check the oil level and quality of every oil tank of the steam turbine and the boiler and the bearings of the auxiliaries i.e. make sure they are normal and qualified; 1.4.2.2 Contact the chemical worker to make up water in the condenser make-up water tank to high level and check their for qualification; 1.4.2.3 Confirm that the TSI, SCS, DAS, MCS, DEH and MEH systems are in normal operation; 1.4.2.4 Confirm that the turbine water feed protection is in normal operation; every drain manual insolating valve is opened and every drain control valve acts correctly; 1.4.2.5 Confirm the heat preservation of the steam turbine proper is good; 1.4.2.6 Make sure every HIP main stop valve, control valve and control mechanisms are normal; 1.4.2.7 Confirm that the sliding key system is normal and the cylinder can freely expand; 1.4.2.8 Confirm that the exhaust cylinder safe valve is complete; 1.4.2.9 Confirm that the emergency drain oil valve is closed and sealed with lead. 1.5 Operation of Auxiliaries and Systems before the Unit Start-up 1.5.1 Operation of Auxiliaries and Systems 1.5.1.1 Start the water circulating pump to supply circulating water for the condenser and check its system, i.e. make sure it is in normal operation; put the other one into standby as the pump in operation is confirmed in normal operation; put the rotary strainer and rubber ball cleaning device into operation as the circumstances many require; 1.5.1.2 Put the open cycle cooling water system into operation and make sure it is in normal operation; 1.5.1.3 Start the condensate delivery pump and make sure it is operating normally; flush the 101
condenser, stator cooling water tank and the deaerator, respectively till qualifying and then make up water to the no rmal water level; 1.5.1.4 Put the condensate system into operation and put its attemperating water into automatic supply as required and put the LP heater water side into operation; if the condensate water qualified is unqualified, open the #5 LP outlet drain valve to flush and blow down; 1.5.1.5 Put the auxiliary steam system into operation; 1.5.1.6 Heat the deaerator till its water temperature is greater than the boiler drum wall temp temper erat atur ure, e, name namely ly 28℃; 1.5.1.7 Put the mainframe lubricating oil system and the oil purification plant into operation and make sure they are operating normally; 1.5.1.8 Put the generator oil, hydrogen and water systems in turn according to the operating specifications of them; 1.5.1.9 Put the mainframe turning gear into operation: 1) Confirm that the mainframe lubricating oil system is in normal operation, the lube oil temper temperatu ature re is is contr controll olled ed rang ranging ing from from 27℃ to 40℃ and its its pres pressur sure e is greate greaterr than than 0.137M 0.137Mpa; pa; 2) Put the jacking oil system into operation; check the jacking oil outlet manifold pressure, i.e. make sure it is 16MPa and record it; check whether the jacking oil pressure of every bearing is greater than 7MPa and compare the said parameter with the jacking oil pressure test records; 3) Check the turning gear current, rotating speed and inside sound after the startup of it and make sure they are normal; 4) Put the turning gear into automatic operation and record the rotors eccentricity; 5) Make the interlock tests for the turning gear and the jacking oil pump in the cooperation of the thermal technicians as the circumstances require and make sure the tests are normal; 6) Full record the primary steam and metal temperature once after the turning gear is put into operation; copy them per hour till the completion of the startup after the gland sealing system is put into operation; Note: before the steam turbine rolls, the turning gear at least needs to continuously run for 4h without abnormality and the rotor eccentricity is less than 110％ of the original value so as to ensure its stable startup. 1.5.1.10 Put the EH system into operation and make sure it is in normal operation. 1.5.1.11 Following Following tests can be pe rformed as required. 1) Static test of the turbine governing system (static characteristic curve and measurement for valves off-time); 2) Turbine local and remote trip tests; 3) Main trip solenoid valve action test; 4) ETS protection test; 5) AC and DC lube oil pump low oil pressure interlock t est of the mainframe; 6) EH pump low oil pressure interlock test. 102
1.5.1.12 Make sure that every pipe drain valve, drain valve of every valve block and the relevant manual drain valves in the main and reheat steam, bypass and extraction steam systems had opened already; 1.5.1.13 Pre-warming operation is determined according to the HP cylinder primary outlet inner wall temperature. 1.5.1.14 Start the motor-driven feed pump; put the HP heater water side into operation while meeting the requirements and check the system, i.e. make sure it is in normal operation; 1.5.1.15 Put the gland sealing system into operation; check the gland manifold pressure and make sure it ranged from 26KPa to 28KPa. The gland steam temperature is matched with the gland metal temperature. 1）Cold state (150℃～260℃）; 2）Hot state 208℃～375℃）; 3）The gland fan inlet's vacuity is maintained at about 2.5KPa. (Operating principal of gland steam: in cold startup mode, pump out vacuum first, and feed gland steam before HP cylinder pre-warming of the unit; in hot startup, feed gland steam prior to pumping vacuum out. The gland fan must be put into operation immediately after feeding gland steam or stopped immediately after the gland steam pressure reaches zero for stopping supply it. 1.5.1.16 Start two sets of vacuum pumps; check their operation, i.e. make sure they are in normal operation; 1.5.1.17 Prepare for igniting the boiler after the condenser vacuum is in place. 1.6 Unit Start-up Parameters and Mode Selection Principal 1.6.1 No matter what kind of startup modes, the main and reheat steam into the steam turbine must must be ensure ensured d above above 56℃ of super superheat heat degree; degree; 1.6.2 The warming time should be confirmed based on the startup-loading chart; 1.6.2.1 The warming time of the unit on initial load with the IP cylinder startup mode after the steam turbine operates at a mid speed and a full speed, and synchronizes is confirmed in terms of the IP steam admission metal temperature, reheat steam pressure and temperature prior to staring; 1.6.2.2 When the unit is operating with the automatic startup mode, the time can be set by referring to the warming time of mid speed, full speed and initial load on the DEH screen on the premise of ensuring the mainframe differential expansion, the outer wall temperature difference and the temperature vitiation rate are within the corresponding limits (see the corresponding curves in appendix); 1.6.3 In cold startup mode, the time is set based on the requirements of the 1.6.2.2 and the main and reheat steam pressure and temperature must meet the requirements of the “cold startup curve” (see the appendix); 1.6.4 In non-cold startup mode, while meeting the requirements of the startup curves under every 103
state, the unmatched value of the main steam temperature and the HP primary metal temperature, the reheat steam temperature and the IP steam admission metal temperature should be ranged from from nega negati tive ve 10℃ to 55℃ as much much as poss possib ible le and and 28 28 ℃-55℃ is op optimal. 1.6.5 The metal temperature variation rate must be met the requirement of the “temperature variation rate and temperature variation relation curves of the HP and IP rotors under various cycle life consumption” while selecting the steam parameters, usually adopting the life loss less than 0.001％ under the HP and IP cylinders metal temperature jump. 1.6.6 The IP cylinder startup mode is preferential. 1.7 Cold Start-up of the Unit
1.7.1 HP cylinder pre-warming 1.7.1.1 Pre-warm the HP cylinder before the boiler ignition in case of the cold startup or the primar primary y inner inner wall wall metal metal temp tempera eratur ture e less less than than 150℃ ; 1.7.1.2 Pre-warming steam is from the auxiliary steam (or cold reheats steam). And the pre-warming pressure is required to be 0.4 ～0.5MPa; temperature is 200～250℃ and the de degree of supe superh rhea eatt is main mainta tain ined ed at at 28 28℃ . 1.7.1.3 Warming conditions: 1）The mainframe trips in turning state; 2）The prima primary ry inner inner wall wall metal metal temper temperatu ature re is less less than than 150℃ ; 3）The condenser vacuum is not less than negative 86.8KPa; 4）The cold reheat pipe and the first extraction electric valve inlet drain valve are opened; 5）The auxiliary steam header pressure ranges from 0.5MPa to 0.7MPa and it is in normal operation; 6）The mainframe VV is closed; 7 ）The f irst ext raction motor-dri ven val ve is full cl osed a nd th e HP cyli cylind nder er exhau exhaust st check valve is closed. 1.7.1.4 Warming operation ⑴ Open the HP cylinder to pre-warm its insolating valve; warm the pre-warming pipe to the
control valve inlet for cylinder warming; keep a drain trap continuously running after fully draining and warming pipe; ⑵ Regulate the opening of the HP loop pipe drain control valve to 20%; ⑶ Close the drain valve of the HP cylinder exhaust check valve inlet pipe; ⑷ Open 10% of the control valve for warming the HP cylinder; 10% of the pre -warming control
valve and open to 30% after maintaining for 20min and continue to open to 55% after 20min for 30% opening; ⑸ Close the first extraction electric valve inlet drain valve in 30min; ⑹ Regulate the opening of the control valve for heating the HP cylinder; control the primary
metal temperature temperature rise rise rate of the the HP cylind cylinder er less than than 1℃ /min, so so as to enable enable the pressur pressure e 104
inside the cylinder to gradually rise to 0.4MPa-0.5MPa and the primary inner wall metal tempe tempera ratu ture re to gra gradu dual ally ly ris rise e to 150 150℃ . 1.7.1.5 Superheat the HP cylinder in case of maintaining current opening after the primary inner wall metal metal tempera temperature ture gradually gradually rises to 150℃; Set the superhea superheating ting time time based on on the “HP cylinder pre-warming superheating time curve” (the following table for reference: the temperature is the primary inner wall metal temperature before pre-warming)
Temp（℃）
20
40
60
80
100
120
150
Time（min）
220
200
190
180
150
110 110
0
1.7.1.6 Operations after the completion of cylinder superheating ⑴ Full open the HP loop pipe drain valve and the f irst extraction electric valve inlet drain valve; ⑵ Put the HP cylinder exhaust check valve inlet drain valve into automatic operation and full
open it; ⑶ Gradually close the HP cylinder pre-warming control valve; check and make sure the HP
cylinder exhaust vent valve is full opened after full closure of the control valve; ⑷ Put the cooling reheat pipe drain valve into automatic operation.
1.7.1.7 Cautions ⑴ In order to meet the requirement of the temperature rise rate, the primary outer wall metal
temperature temperature rise rise must must be less less than 1℃ /min that that is maintai maintained ned and control controlled led by regulatin regulating g the reverse flow valve, loop pipe drain valve and the HP cylinder exhaust check valve inlet drain valve. ⑵ Pressure inside the HP cylinder when superheating should be ranged from 0.4MPa to
0.5MPa and not greater than 0.7MPa; Otherwise additional thrust force can be gen erated for the unit. upper and and lower lower cylinders cylinders temperature temperature difference difference is less less than than 35℃ . ⑶ The upper ⑷ The cylinder expansion, HLP cylinders differential expansion, axial displacement and rotor
eccentricity should be within the allowable range. ⑸ Notice of monitoring the operating conditions of the turning gear; ⑹ It needs at least 30min to exhaust steam for pressure drop after the completion of the
superheating. ⑺ The valve opening is for reference only and the metal temperature rise limit and superheating
pressure should be the main basis.
1.7.2 HP control valve chamber pre-warming 1.7.2.1 As the metal temperature temperature of of the control control valve valve chamber chamber is less less than 150℃ , it must must be pre-warmed with pre-warming steam from the #2MSV pre-inlet valve before the steam turbine startup. 1.7.2.2 The pre-warming steam is from the main steam. It is used for pre-warming the control 105
valve chamber chamber when the main steam steam tempera temperature ture is greater greater than 271℃ and the HP HP cylinder cylinder superheating is completed. 1.7.2.3 Procedures: 1）Check the steam turbine and make sure it trips; 2) Check the EH oil system and make sure it starts normally and the control mechanism oil pressure is in place; 3) Confirm that the main steam manifold drain, main steam valve block drain and loop pipe drain valves are opened; 4) Make Make sure sure the the main main steam steam tempe temperat rature ure is is greater greater than than 271 271℃ ; 5) Press the LATCH button on the steam turbine AUTO CONTROL screen and confirm the steam turbine has latched successfully; 6) Press down the CV CHEST WARMING button; select OPEN in a pop-up window; pre-warm at the time of 21% opening of the MSVR; 7) Observe the inner and outer walls metal temperature difference of the control valve chamber; press down the OFF button of the CV CHEST WARMING when the difference is higher than 80℃;the ;the MSVR MSVR is is surel surely y close closed d while while the MSVR MSVR-CLOSE lamp is on at this time; press down the ON button button to continue continue to pre-war pre-warm m as the differe difference nce is is less less than than 70℃ ; 8) Repeat the said operation till the outer and inner walls metal temperatures are totally up to 180 180℃ and and the their ir diff differ eren ence ces s are are less less than than 50℃ ; abo above ve 1h pre pre-warming means the completion of the pre-warming for the control valve chamber; and then press the STOP button of the steam turbine and make sure every valve is closed. 1.7.2.4 The control valve chamber pre-warming is completed and the boiler continues to rise temperature and pressure.
1.7.3 Rolling and speed rise of the steam s team turbine 1.7.3.1 Check and confirmation for following parameters: Lube oil pressure greater than or equal to 0.137MPa; Lube Lube oil oil tem tempe pera ratu ture re rang rangiing from from 40℃ to 46℃ ; EH oil pressure ranging from 10.7 MPa to 11.7MPa; Jacking oil manifold pressure ranging from
MPa to 16MPa;
Eccentricity less than 100% of the original value; LP differential expansion ranging from negative 4. 6mm to 19.8mm; HP and IP differential expansion ranging from negative 5. 3mm to 10.3mm; HP cylinder primary upper and lower cylinders temperature difference less than 50/35℃ (inner and outer casings) 1.7.3.2 Check and confirmation of following drain valves at every section in open state: 1）HP section: HP main stop valve inlet drain, HP main stop valve block drain, HP loop pipe drain, the first extraction electric inlet and outlet drain; 2）IP section: the HP cylinder exhaust check valve inlet and outlet drain, the third and fourth 106
extraction electric valve inlet and outlet drain, IP combination valve block drain and IP main steam pipe drain and IP cylinder steam exhaust drain; 3）LP section: The fifth and sixth extraction check valve and inlet drain; 4）Check the HP cylinder exhaust check valve and locally check the cylinder of the HP cylinder exhaust check valve, i.e. make sure they are opened; confirm the HP cylinder exhaust check valve is free; 1.7.3.3 The TSI measuring data are in allowable range. Record following parameters before rolling and confirm following protections has put into operation: 1) Low lube oil pressure protection; 2) Low fire-resistant oil pressure protection; 3) Large axial displacement protection; 4) Bearing vibration protection; 5) Electric over-speed protection; 6) Electric failure shutdown protection; 7) The key switch on the ETS thermal control panel in the test is allowed to b e at “PUT” position. 1.7.3.4 The unit steam and water qualities are qualified. 1.7.3.5 The boiler combustion, steam temperature and pressure are stable.
1.7.4 The steam turbine is started s tarted by means of cold IP cylinder. 1.7.4.1 Confirmation for rolling steam parameters
Main
steam
Main steam
6.0MPa
temp
pressure Reheat
370℃
steam
1.1M 1.1MPa Pa
Rehea Reheatt stea steam m temp temp
320 320℃
pressure Condenser vacuum
＞－86.8KPa
HP bypass outlet flow
1.7.4.2 Operations at the DEH operating station: 1）Click the START MODE button on the AUTO CONTROL screen; select the IP START in a pop-out window; 2）Press the RUN button to the position of YES on the AUTO CONTROL screen; make sure the MSV and the RSV are full open after executing the RUN command; 3） Alter the AUTO/MAN AUTO/MAN button to AUTO; AUTO; At this time, it is in operator automation mode. 1.7.4.3 Confirm that the VV and the BDV are opened; 1.7.4.4 Locally check and make sure the HP cylinder exhaust check valve is in free status; 1.7.4.5 Click the VALVE VALVE POS LIMIT on the AUTO LIMIT screen to set it as 120%; 1.7.4.6 Press down the HEAT SOAK button on the AUTO CONTROL screen, and then select ON button. 107
1.7.4.7 Friction check 1) Click the “c and TARGET” button on th the e AUTO CONTROL screen to select the target rotating speed as 200r/min and acceleration rate as 100r/min/min; 2) Press the GO/HOLD button on the AUTO CONTROL screen and select the GO to roll the steam turbine; 3) In case the rotating speed is faster than the turning speed, check the turning gear, i.e. make sure it is normal; if it automatically trips, latch to stop immediately; 4) In case the turbine rotating speed reaches 200 r/min, press down the FRIC CHK button on the AUTO CONTROL, CONTROL, confirm all valves are closed and begin to check the turbine friction; 5) Carefully listen sound inside the steam turbine and keep the stator running during friction check period; 4) In case the turbine rotating speed reaches 100r/min, stop checking friction and confirm the unit is in normal operation. 1.7.4.8 In case of unit latching again, operate mid-speed heat soaking, namely 1500r/min. 1）Press down the ACCRATE and TARGET keys to set the acceleration rate and target rotating speed as 100r/min/min and 1500 r/min, respectively; 2) Check the #1 and #2 MSVs and the #1-#4 CVs, i.e. make sure the MSVs are opened and the CVs are slightly opened; in case the turning speed reaches 400 r/min, the CVs are locked and the turbine rotating speed is controlled by the ICV. 3) The turbine speed rises to 1500r/min under the control of the ICV and the heat soaking mid speed is maintained at 1500r/min. The mid speed heat soaking will be completed after the confirmation of the following parameters: a) The The primary primary inner wall temperature temperature of the HP cylinder cylinder greater greater than than 320℃ ; b) The inner wall metal temperature of the IP cylinder steam admission chamber greater than 320℃; c) The HIP cylinder expansion greater than 8mm 1.7.4.9 During the mid-speed heat soaking, keep the main and reheat steam pressure and temperature stable and the bypass control normal; check the cylinder expansion, HIP differential expansion, axial displacement, upper and lower cylinders temperature difference and HIP cylinder exhaust metal temperature, vibration of every bearing and condenser pressure, i.e. make sure they are controlled within the allowable range; 1.7.4.10 Check the lube oil temperature, metal temperature of every bearing and return oil temperature, i.e. make sure they are normal; 1.7.4.11 After the completion of the mid-speed heat soaking, press down the HEAT SOAK button and select the OFF; and then confirm the CV is gradually turned down till full closing. The unit rotating speed is 1500r/min under the control of the ICV and its target rotating speed is set as 3000 r/min; then the steam turbine speed continues to rise; 1.7.4.12 In the process of speed rising, the unit through the combined critical speed at the 108
acceleration rate of 300r/min/min should be fast and stable; the vibration of the bearing covers should be greater than 0.08mm and the bearing vibration should not exceed 0.25mm; otherwise unit trips; 1.7.4.13 When the turbine rotating speed reaches 2500r/min, check the jacking oil pump, i.e. make sure it is automatically stopped; otherwise, manually stop it and put the standby pump into operation; 1.7.4.14 When the turbine rotating speed reaches 3000 r/min, warm it up during the warm-up period provided by the startup modes; 1.7.4.15 When the mainframe operates at the constant spe ed, overhaul the unit and every system, i.e. make sure they are operating normally. 1.7.4.16 Selective tests as required: 1) Manual tip test 2) Emergency governor oil injection test 3) OPC test 4) Main trip solenoid valve test 5) Valve leakage test 1.7.4.17 After passing the said tests, stop the TOP and the MSP; check the mainframe lube oil pressure and the operation of the main oil pump i.e. make sure they are normal; and completely check whether the main equipment and auxiliaries of the unit are normal; 1.7.4.18 Confirm that the generator hydrogen cooler and the stator cooling system are automatically controlled and normal; 1.7.4.19 Place the AUTO SYNC at the position of ON as required by the duty d uty director.
1.7.5 Cautions during rolling and speed raising 1.7.5.1 The steam parameter should be kept stable in the process of speed rising; 1.7.5.2 Every operational parameter during the unit startup should be checked at any time and their normality should be guaranteed as well; 1.7.5.3 The chemical technician should test the water quality regularly during the unit startup, so as to guarantee the steam-water quality; 1.7.5.4 During the speed rising, it must ensure that there is no abnormal alarm occurred at the DEH; otherwise, next step is unavailable at the DEH AUTO mode; 1.7.5.5 Make sure the LP cylinder spray valve has put into automatic operation under the control of exhaust exhaust temperature temperature that is maintai maintained ned below below 50℃ before the rolling rolling and and the spray spray valve valve outlet outlet pressure is about 0.5MPa; 1.7.5.6 The condenser vacuum must reach negative 86.8KPa before the rolling; 1.7.5.7 The main steam flow during the rolling should be controlled in conformity with the opening of the LP bypass valve that is adjustable in case the reheat steam pressure is kept at 1MPa; 1.7.5.8 During the rolling, it must closely monitor the exhaust metal temperature variation of the HP cylinder and confirm the HP cylinder exhaust vent valve is open; 109
1.7.5.9 During the startup, it must note that the metal inner and outer walls temperature of every part of the steam turbine should be controlled within the maximum value provided in the allowable temperature difference chart; the metal temperature change rate should be controlled within the maximum value provided by its rate change curve chart and the mainframe axial displaced is within the allowable range; 1.7.5.10 During the speed rising of the steam turbine, it should take note of the variation of the cylinder expansion, HIP and LP cylinders differential expansion. When the differential expansion increases apparently, further increase of it can be controlled by means of regulating the steam parameter and stabilizing the rotating speed (the steam temperature should reduce in case positive differential expansion increases). In case that the HP differential expansion is as large as the value of shutdown, it must be stopped by breaking vacuum and continuously turn till the cylinder temperature is matched with the rotator temperature. It must avoid unit trip in case of abnormal LP differential expansion increase. 1.7.5.11 During the speed rising, it must listen carefully the fricative sound of the unit in site and check the vibration and bearings metal temperature. If there is any abnormity, stop to find the causes in time. And the unit vibration during the heat soaking must meet the following requirements: When it is warmed up at a low speed, it must focus on the changes of the bearings vibration, namely below 1300r/min is corresponding to the bearing cover vibration less than 30μm; Otherwise, trip it immediately. Mid-speed heat soaking is forbidden. When it is warmed up at a combined critical speed, the bearing cover vibration is less than 100μm or the bearings vibration is less than 250μm; otherwise, trip it immediately. The heat soaking at the speed in excess of the critical speed or speed reduction is forbidden. The bearing cover vibration should not exceed 50μm above the first critical speed; otherwise, find out the causes and relief the vibration till it is less than 30μm. Long-term idle at large amplitude is not allowed. As the bearing cover vibration reaches 80μm or the bearing vibration is up to 250μm, latch immediately; after the rotor is still, put the continuous turning gear into operation; check the rotor's bending and the outer and inner walls temperature difference of the upper and lower cylinders; listen carefully; find out the causes and remove them; and then restart it. 1.7.5.12 During speed rising, the rotating speed should be maintained and the operation at the speed in excess of the critical speed in case the speed is within the critical speed should be kept as well under following conditions: 1) The bearing vibration greater than 0.125mm; 2) The HIP differential expansion greater than 10.3mm or less than negative 5.3mm; the LP differential expansion less than negative 4.6m or greater than 19.8m 3) High High LP cyli cylinder nder exhaust exhaust temp tempera eratur ture e (80 (80℃ ) 4) Low mainframe vacuum (less than negative 86.8Kpa) 1.7.5.13 Temperature Temperature rise rate range of every part of the unit 1）Main Main steam steam temper temperatur ature e less less than than 1.5 1.5℃ /min /min 110
2）Reheat Reheat steam steam tempera temperatur ture e less less than than 2℃ /min /min 3）HIP cyli cylinder nder wall wall temp tempera eratur ture e rise rise less less than 1.5 1.5℃ /min /min 4）Main and reheat reheat steam steam pipe walls walls temperature temperature rise less than 6℃ /min 5）Main Main control control valv valve e casing casing temper temperatur ature e rise less less than than 6℃ /min /min 1.7.5.14 The temperature difference of every part of the steam turbine should be within the range as follows: 1）The outer and inner walls temperature difference of the HIP cylinder outer casing and the HP inner inner casi casing ng sho shoul uld d be less less than than 80 80℃ ; 2）The outer and inner walls temperature difference of the HP main stop valve casing is less than 80℃; 3）The outer and inner walls temperature difference of the HIP cylinder outer casing and the HP cylind cylinder er inner inner casi casing ng is is less less than than 80℃; 4）The outer wall upper and lower halves temperature difference of the HIP cylinder outer casing is le less th than 80 80℃; 5）The outer wall upper and lower halves temperature difference of the HIP cylinder inner casing is le less th than 80 80℃; 6) The inner wall upper and lower halves temperature difference of the HIP cylinder inner casing is le less than 35 35℃; 1.7.5.15 As the unit is operating at a constant speed and a water spray device is put into operation, the LP cylinde cylinderr exhaust exhaust temperature temperature is is excessivel excessively y high, namely namely 107 107℃ as well after dispos disposal, al, manual shutdown should be applied. 1.7.5.16 After the unit is operating at a constant speed, if there is superheating occurred at the HP cylinder cylinder and its its exhaust exhaust steam steam temperatu temperature re is up to 432℃ after disposal, disposal, manual manual shutdown shutdown should should be applied. 1.7.5.17 Rotating speed acceleration and reduction by manually setting valve position is forbidden during normal rolling and speed rising of the steam turbine. 1.7.5.18 Before reaching the synchronous revolution, the lube oil temperature of the steam turbine shou should ld be rang ranged ed fro from m 38 38℃ to 42℃ , EH EH oil oil pres pressu sure re shou should ld be 10.7 10.7～11.7MPa and the oil temp temper erat atur ure e sho shoul uld d be be 45 45℃ . 1.7.5.19 As the turbine rotating speed reaches 3000r/min, the main oil pump inlet pressure must be ranged from 0.098MPa to 0.147MPa and the bearing lube oil pressure should be ranged from 0.137MPa to 0.176MPa. In case its pressure is not less than 1.372MPa, the TOP and MSP can be stopped; otherwise, causes must be found out, repair and adjustment are required. 1.7.5.20 When the generator rotating speed reaches 1500r/min, its carbon brush should be checked, i.e. making sure there are no abnormality and jump. 1.7.5.21The excitation can be put into operation at the time of receiving the synchronization command in the cooperation of the duty director while the unit is stable and has not abnormal alarm signal after the turbine rotating speed reaches 3000r/min. 111
1.7.6 Generator synchronization To ensure the normal operation of every device, complete inspection for every system is required after the generator synchronizes.
1.7.7 Unit load-up 1.7.7.1 Low load warm-up 1） After the unit synchronizes, synchronizes, it operates on 5% load, namely 30MW for 60min; Meanwhile, the LP cylinde cylinderr exhaust exhaust temperature temperature should be monitore monitored d and less than 52 52℃ ; 2) The main reheat steam parameter must be kept stable during initial load warm-up period and the bypass must be constant pressure mode; 3) The control indexes of the unit including expansion, differential expansion, and temperature difference and so on are required to be checked and monitored. And it must ensure they are normal. 4) During the low load warm-up period of the unit, start and check a set of feed pump, and warm up the steam turbine. 5) Confirmation for automatic operation o f following control systems and valve control: a）Deaerator pressure control; b）Deaerator water level control; c）Furnace draft and air supply volume control; d） Auxiliary air baffle plate control; e） Air pre-cooler cooling end temperature control; f ）Steam turbine proper and HIP drain valves control; g）Generator stator cooling water control; h）Exciter air temperature control. 6) In case the steam turbine differential expansion, total expansion, bearing vibration, bearing shell temperature, oil temperature and pressure, warm-up time totally meet the requirement, it can be confirmed the completion of warming. 7) Inform of the chemical technician to test the condensate; recovery it to the deaerator after it is qualified; put the deaerator water level control valve into automatic operation; put the condensate polishing unit into operation when the condensate temperature is less than 50℃ and close the polishing manual bypass valve; 8) Put the turbine, generator and boiler interlock protection into operation. 1.7.7.2 Switchover of the HP and IP cylinders 1）Switchover of the HP and IP cylinders is automatically applied to the unit in case the load is greater than 7% after warming up on initial load. 2）It must note that the main steam temperature through the HP governing-stage working should be matched with the metal temperature before the switchover of the HP and IP cylinders. In general case, the temperature ranges are as follows: Main steam: 6.0MPa
380～390℃ 112
Reheat steam: 1.1MPa
360～370℃
3）The main steam must be kept basically stable in the process of switching IP cylinder single steam admission to HP and IP cylinders combined ste am admission. 4) The HP cylinder check valve must be opened and the VV must be automatically closed during switching over. 5）With the load increase, the #1 and #2 IP control valves are widely opened and the BDV is automatically closed. 6）Completely check the relevant drain valves and e nsure they are automatically closed after the completion of the switchover. switchover. 7）The LP heater sliding starts at random. The HP heater steam side can be put into operation from high to low side after the th e completion of the switchover. 8）During switching over, the unit loads up on 5％/min load rate till the HP and LP bypass valves are full closed. At this time the switchover is completed. 1.7.7.3 Loading up to 180MW 1）Set the target rotating speed and loading rate on the DEH control screen as 180MW and not greater than 3MW/min（0.5%/min）, respectively; press the GO/HOLD key to set it as GO state and load up; 2）Start up the second milling system as the output of the coal pulverizer in operation reaches 80% according to the main steam pressure requirement; inform of the ash control attendant to operate the slag an d dust removal systems after the pulverizer starts; 3）Check the drain valve at HP section in the steam system, i.e. make sure it is closed when the load is up to 60MW; 4）Gradually rise temperature, pressure and load based on the startup curves of the unit; 5）The unit after being reassembled or overhauled should be firstly started up on 180MW load for 3-4h stable operation, and then it is desynchronized after normally loading down. A mainframe over-speed test should be made for it as well. 6）When the fourth extraction pressure of the deaerator is greater than 0.15MPa, it is heated with steam provided by the fourth extraction instead of the auxiliary steam, and then it is in sliding pressure operation. 7） Check the drain valve at the IP section in the steam system, i.e. make sure it is closed when the load is up to 120MW. 8）Combine one turb-feed pump that h ad warmed up with the feed water system in case the load ranges from 120MW to 150MW; closely monitor the boiler feed water flow during combination operation, i.e. make sure it is stable; meanwhile, roll the second feed pump to warm up the steam turbine. 9） After the steam drum water level is is stabilized, it will be automatically controlled based on the operating condition of the turbo-feed pump. 10） After the unit load is stabilized on 150MW load, put the cold reheater to the self-sealing 113
system into operation and provide gland steam instead of auxiliary steam. 12) When the unit load is above 150MW, cold reheat steam supply is instead of the auxiliary steam supply. And the auxiliary steam is provided for the steam gland station system for thermal standby instead. The system should automatically keep the pressure of the steam supply manifold. 13) When the third extraction steam pressure is higher than the deaerator pressure (0.2MPa), drain the water of t he #3 HP heater to the deaerator. 14) After the unit load reaches 180MW, confirm the relevant LP drain valves of the unit are normally closed, warm up according to the startup curves and put the power circuit and TPC into operation as required. 15）If an over-speed test is necessary for the unit, it can be performed after the steam turbine over-speed test is made, and the unit is desynchronized with a reduced load and had stably operated on 180MW load for 3-4h. 1.7.7.4 Loading to 300MW 1）When the target load is set as 300MW, the loading rate and pressure rising rate are controlled not exceeding 3MW/min and 0.1MPa/min, respectively. 2）Slowly load up the boiler boi ler according to the main steam pressure requ irements; 3）The unit is in automatic sliding pressure o peration and in CCS control instead of DEH control, and it exits HP bypass automatic operation as its load approximates to 240M. The signal for the CCS system is sent out by the DEH control system. The unit begins to load up with the boiler pressure rise till 90% of HP control valve’s opening after it is controlled by the CCS. (Switchover of the DEH and the CCS: after receiving the request signal of the CCS, the CCS AUTO REQUEST on the DIGITAL SIGNAL screen of the DEH turns green. Then press the CCS CTL key and select ON; at this time the target load of the DEH is set by the CCS; automatically cut off “load feedback” and “governing stage pressure feedback” and alter the inherent frequency modulation to 30r/min; at last the CCS is put into operation. If it needs to cut off the CCS, press the CCS CTL key and select OFF.) 4） After the unit load reaches 240MW, merge the second turbo-feed pump in the feed water system; stop the motor-driven pump and open the pumps’ outlet valve for standby. 5）When the load is up 300MW, the main steam pressure should be 10.0MPa, the main steam temperature temperature and the reheat reheat steam temperature temperature approxim approximates ates to 510 510℃ , respectivel respectively y. 1.7.7.5 Loading to 600MW 1）When the target load is set as 600MW, the loading rate and pressure rising rate a re controlled not exceeding 6MW/min and 0.16MPa/min, 0.1 6MPa/min, respectively. respectively. 2）When the load is 360MW, the auxiliary steam header steam is supplied from the fourth extraction. By stopping providing steam for the cold reheater to the steam gland system, the unit is self-sealed. 3）When the load is 480MW, perform a vacuum leakage test for the steam turbine according to 114
requirements. 4）When the load is greater than th an 540MW, the main steam pressure should reach the rated value and the constant pressure operation should be instead of the sliding pressure operation. 5）Completely check and adjust the unit to make its devices and systems operate normally and put all thermal automatic control devices into operation; 6）Put another circulating water pump into operation on a case basis or regulate the operating mode of the circulating water.
1.7.8 Cautions during loading of the unit 1.7.8.1 Cautions for the steam turbine 1）Take note of the condenser, deaerator, heater and stator cooling water tank water level, oil tank level and oil temperature during startup, i.e. make sure they are normal and conforming; 2） Check the automatic temperature control of every cooler, i.e. make sure it is normal. 3） During the startup of the unit, the chemical technician should continuously monitor the steam, oil and water qualities, i.e. make sure they are qualified. 4 ）Switching the DEH control to the CCS control can be applied after completing steam admission switchover and confirming the valve position command displayed by the DEH is matched with the CCS load command. 5）When the LP LP cylinder cylinder exhaust temperature temperature is is higher higher than 52 52℃ , to avoid avoid overheat overheat LP exhaust cylinder, it is unsuitable for accelerating load. And attemperating water condition is required to be monitored. 6）It is unsuitable for long-term operation on the loa d less than 180MW and it is required to take note of the HP cylinder exhaust metal temperature variation. 7）The loading rate of the unit is set to at least make the metal temperature change rate of the cylinder and the valve chamber, the inner and outer walls temperature difference meet the requirements of the metal temperature changes rate and the temperature difference control curves. Load stabilization if necessary can be realized by improving the variation of the metal temperature and differential expansion through adjusting the steam parameter. 8）Make gland steam overflow flow to t he #8A LP heater after the unit operates normally; 9 ） Start up the second circulating water pump in time depending on the situation of the mainframe vacuum and the cooling water temperature; 10）Make up hydrogen for the generator in time to boost up its pressure to the rated value during the unit loading; 11）Put the steam turbine-boiler coordinate control mode into operation as early as possible in case the unit load is greater than 50%. 1.8 Warm and Hot Start-up of Unit 1.8.1 Operating principal 1.8.1.1 What is the key for the warm and hot startup of the unit is matchup of the main and reheat 115
steam temperature with the HP and IP inner cylinders metal temperature of the steam turbine. The operation is similar to the cold startup of the unit. To avoid the production of excessive thermal stress resulting from rotor metal temperature drop, the unit must be loaded as soon as possible at the warm and hot startup modes. 1.8.1.2 In addition to strict execution of relevant manual and operating procedures of the cold startup, the acceleration, warm-up and loading must be executed according to the warm and hot startup curves. 1.8.4 The mismatch value between the main, reheat steam temperature and the HP cylinder primary, IP admission chamber metal temperature should be ranged within -55～+110℃ and the degree of superheat superheat of of the main main and reheat steam temperature temperature should be above above 56℃ as the steam turbine rolls. 1.8.5 At turning state, gland steam must be supplied prior to pumping out vacuum. The gland steam source selection is more inclined to the high temperature steam that is able to match with the gland metal temperature on the basis of the cylinder temperature. Full water drainage and pipes warming is required before supplying the gland steam. 1.8.6 To meet the requirement of unit service life, the steam turbine bypass system must be put into operation in time and the main, reheat steam temperature must be strictly controlled in accordance with the temperature and pressure rising rate after the boiler ignition. 1.8.7 All turbine water induction prevention valves must be opened at the time of hot (warm) startup; drain time at every drain point of the main and reheat steam pipes must be not less than 5min before the turbine rolling. 1.8.8 It must be confirmed that the steam turbine is in turning state or idle running but not at the critical speed zone before the turbine rolling. Idle running at the critical speed zone is strictly forbidden. 1.8.9 The acceleration rate, loading rate and warm-up time are determined according the startup and loading chats. 1.8.10 The HEAT SOAK will be not executed for the steam turbine at the IP cylinder startup mode. It is rolled to 400r/min with the HP control valve. 1.8.11 It must closely monitor the primary metal temperature change rate of the HP and IP cylinders, the HP and LP differential expansion, the cylinder expansion, axial displacement variation and the unit vibration condition when the steam turbine speeds up by rolling. 1.8.12 Mid-speed heat soaking for the steam turbine can be avoided at the allowable condition. To protect the cylinder from cooling, it can be fast rolled to raise speed. 1.8.13 Cautions for warm and hot startup of the unit 1.8.13.1 All turbine water induction prevention valves must be opened at the time of hot (warm) startup; the main and reheat steam pipes and loop pipe drain valve must continuously drain water for not less than 5min before the turbine rolling. 1.8.13.2 Not less than 5min water drain before the rolling is required in case the inner walls upper 116
and lower lower casings casings temperatur temperature e difference difference of the the HP and IP IP cylinders cylinders is not greater greater than than 35℃ ; and the inner and outer walls metal temperature difference of the HP and IP valve blocks ranges within the requirements of the metal temperature difference curves. To avoid steam-water attack, high water level operation of the condenser during the water drain is forbidden. 1.8.13.3 During rolling and synchronizing, the main steam flow of the steam turbine must be corresponding to the opening of the LP bypass valve and the reheat steam pressure is within adjustable range, namely 1.0MPa. The main steam flow before switchover of HP and L P cylinders must meet the requirements of the steam flow of corresponding load after the completion of load-up. 1.8.13.4 After the unit operates on initial load, its fast load-up can be realized in case of ensuring the LP LP cylin cylinder der exhau exhaust st tempe temperat rature ure less less than 52℃ . 1.8.13.5 During the unit loading, similarly, the metal temperature change rate and the inner and outer walls temperature difference of every part of the steam turbine must be controlled to meet the requirements of relevant curves. 1.8.13.6 The inspection and pre-warming for the turbo-feed pumps must be timely. The first pump must be rolled to raise speed as soon as possible and merged into the feed water system. 1.9 Extreme Hot Start-up of Unit 1.9.1 It must be confirmed that the unit is at extreme hot state displayed on the DEH. 1.9.2 With IP cylinder rolling at the extreme hot startup, to protect the boiler against fast cooling, the boiler must be slowly depressurized by draining water and putting the bypass system into operation. 1.9.3 Extreme hot startup rolling parameters
Main steam pressure
12.9MPa
Main steam temp
＞500℃
Reheat steam
1.1MPa
Reheat steam
＞480℃
pressure Condenser vacuum
temp ＞－90KPa
HP bypass valve
＞190t/h
outlet flow 1.9.4 Relevant specifications and cautions for extreme hot startup 1.9.4.1 In case the unit in operation trips resulting from failure, but can be restarted immediately, vacuum breaking is unnecessary. unnecessary. 1.9.4.2 What is the key for the extreme hot startup of the unit is matchup of the main and reheat steam temperature with the HP and IP inner cylinders metal temperature of the steam turbine. The operation is similar to the cold startup of the unit. To avoid the production of excessive thermal stress resulting from rotor metal temperature drop, the unit could roll, rise sped and synchronize fast to be loaded according to the cylinder temperature and temperature difference curves. 1.9.4.3 All turbine water induction prevention valves must be opened at the time of extreme hot 117
startup; the main and reheat steam pipes and loop pipe drain valve must continuously drain water for not less than 5min before the turbine rolling. rolling.
Not less than 5min water drain before the rolling
is required in case the inner walls upper and lower casings temperature difference of the HP and IP cylinder cylinders s is not greater greater than 35℃ ; and the inner inner and outer outer walls metal metal temperatu temperature re differenc difference e of the HP and IP valve blocks ranges within the requirements of the metal temperature difference curves. To avoid steam-water attack, high water level operation of the condenser during the water drain is forbidden. 1.9.4.4 During rolling and synchronizing, the main steam flow of the steam turbine must be corresponding to the opening of the LP bypass valve and the reheat steam pressure is within adjustable range, namely 1.0MPa. The main steam flow before switchover of HP and L P cylinders must meet the requirements of the steam flow of corresponding load after the completion of load-up. 1.9.4.5 After the unit operates on initial load, its fast load-up can be realized in case of ensuring the LP cyli cylinde nderr exhaus exhaustt tempe temperat rature ure less less than than 52℃ . 1.9.4.6 During the unit loading, similarly, the metal temperature change rate and the inner and outer walls temperature difference of every part of the steam turbine must be controlled to meet the requirements of relevant curves. 1.9.4.7 The inspection and pre-warming for the turbo-feed pumps must be timely. The first pump must be rolled to raise speed as soon as possible and merged into the feed water system.
2. Normal Operation and Maintenance of Unit 2.1 Routine Maintenance and Requirements 2.1.1 Patrol and inspect every device in operation and their standby devices on time with necessary tools and safety appliance by carefully watching, touching, smelling and listening, i.e. make sure they are operating normally; compare the readings of the filed meters with the centralized control meters, if there is any abnormality, find out the causes and take right measures to solve them to ensure the unit in normal operation. 2.1.2 The operator and inspector should check the meters on time and compare, analyze their readings. At the time of finding any parameter deviating from the normal value, they must find out the causes and take right measures, a nd then report to the duty director. 2.1.3 If there is defect, they must take necessary precautionary measures, record carefully the defects that have possible influence on safe and economic operation of the unit or equipment and systems in accordance with the Defect Management System and report to the duty director. 2.1.4 Complete routine switchover and test work in compliance with the requirements of
Equipment Routine Switchover and Test Test System ; 2.1.5 Regularly check the auxiliary mechanical bearing oil level and oil quality, i.e. make sure they 118
are normal, add oil or refresh it in time; 2.1.6 Supervise the condenser, feed water, boiler water, steam, generator stator cooling water, lube oil, EH oil quality in coordination with the chemical technician; 2.1.7 Fulfill the other relevant work assigned by the supervisor; Regulate the operational parameters of the unit, every device and system in time; 1 To meet ambient load need, regulate the load in time by means of constant-sliding pressure according to the dispatching requirement; control the load variation within 6MW～15MW/min; 2 Regulate the steam temperature and pressure in time and keep them normal; control the boiler evaporation capacity within the rated value; 3 Check the automatic manual condition of the condenser sump make-up water, condensate and feed water based on the unit load and main steam flow; keep the condenser, deaerator and steam drum water levels within normal range; 4 Reasonably regulate the operating mode of the circulating water system and the open cooling water system according to operation of the unit and the seasonal variation; 5 Regulate the cooling water flow according to oil, air and water conditions of every device to keep then in normal range; 6 Monitor other devices and systems’ parameters and regulate them to normal range. 2.2 Operational Parameters of Unit
2.2.1 Operational parameter limit of steam turbine
Name Main
Main
reheat
flow
steam
Main
parameters
steam
steam
pressure Main
steam
Normal
Maximum
Minimum
Value
Value
Value
t/h
1787
2028
—
—
MPa
16.7
17.5
—
—
℃
538
546
MPa
3.3
3.63
—
—
℃
538
546
—
—
Unit
temp Reheat
steam
pressure Reheat
steam
temp
一
Main or reheat steam
parallel
pipes
bilateral
Remarks
℃
≤41
temp difference
—
than within year
119
less 11℃ the
Governing stage pressure HP
MPa
11.7
—
MPa
3.67
4.58
—
—
℃
321
420
—
432 trip
kPa(a)
＜13.5
13.5
—
≥
℃
＜52
80
—
≥107 trip
cylinder
exhaust pressure HP
cylinder
exhaust
temp
Condenser back pressure LP
cylinder
exhaust
temp
Axial
mm
displacement Steam
HIP differential
turbine
expansion
proper
LP
parameters
differential
expansion Mainframe
Bearing vibration cover
vibration Lube
oil
pressure Lube oil temp
Lubricating oil system parameters
mm
Journal bearing
bearing
bearing
abrasion Bearing oil temp
return
10.3 4.6～ 19.8
1.05
≥10.3
≤
5.3
≥19.8
≤
4.6
value×1.1
value×1.1
mm
＜0.125
≥0.125
mm
＜0.05
≥0.05
MPa
≥0.176
—
0.103
℃
40～50
≥50
≤40
≥+1.2 or ≤
－1.65 trip ≥11.6 or ≤
－6.6 trip ≥30 or ≤－
8.0 trip
—
—
—
0.25 trip
≥0.08 trip
0.069 trip 27 ～ 40 as turning Generator
℃
＜107
≥110
—
high
limit:
105 ℃
＜85
≥85
mm
＜0.6
≥0.6
℃
＜75
≥75
metal temp Thrust
5.3～
≤
＞original
metal temp Thrust
0.6
≥0.6
≤original
mm
eccentricity
Bearing
mm
1.05～
trip
120
—
—
≥0.8 trip
—
—
AC sealing Generator oil, hydrogen and water parameters
oil pump in Generator
automatic
oil-hydrogen
MPa(a)
differential
0.056±0.02
0.076
0. 0.036
pressure
operation as
the
pressure is as less as 35kPa
Generator hydrogen
MPa
0.414
—
0.2
—
%
98
—
≥96
—
℃
≤－21
leak
m3/d
≤13～19
—
—
—
inlet
℃
≤65
65
—
—
outlet
℃
35～46
46
35
—
pressure Generator hydrogen purity Generator hydrogen dew-point temp Generator hydrogen volume Hydrogen cooler temp Hydrogen cooler temp Generator
≤0.68 MPa
sealing pump
oil outlet
MPa
＞0.68
pressure Sealing
pump interlock
pad
℃
35～45
℃
≤75
KPa
-90～-96
inlet oil temp Sealing
standby
pad
outlet oil temp Vacuity vacuum tank
in
121
≤-88 alarm
Water temp must
Generator stator
entering
℃
42～48
48
42
water temp
be
higher
than hydrogen temp Hydrogen
Generator hydrogen-water differential
pressure MPa
＞0.04
—
0.04
pressure
must
be
higher than water pressure
Generator stator
water
m /h
3
92
MPa
0.196
—
72
—
flow Generator entering
water
pressure 2.3 Adjustment and Maintenance for Normal Operational Parameters of Unit
2.3.1 Task and purpose of operational adjustment for the unit 2.3.1.1 Meet the requirements of unit load and maintain the evaporation capacity within the rated range; 2.3.1.2 Maintain the normal steam pressure and the main an d reheat steam temperature in normal range according to the sliding-constant pressure curves of the unit; 2.3.1.3 Balance the feed water and maintain the boiler steam drum water level in normal range; 2.3.1.4 Ensure the quality of the boiler water and steam is qualified; 2.3.1.5 Strengthen adjustment to try to keep the unit operating at sound state, so as to improve the efficiency of the unit.
2.3.2 Supervision and adjustment for main operational parameters of the unit 2.3.2.1 Load adjustment 1) The CCS control mode is usually used for the load adjustment. Other control modes can be employed in case the CCS is failed or the actual operating condition requires. 2) Too fast load variation rate is unallowable. It must be controlled about 1.5 %( 9MW/min) and not exceeding 2.5%/min under normal condition and its maximum and minimum values should be limited. 3) To guarantee the safe operation of the unit and meet the operating requirements, as the load 122
fluctuates greatly, the load adjustment should be performed by stages in accordance with the constant-sliding-constant pressure operating curves, the requirements of the metal temperature change rate and temperature difference of every part of the steam turbine, and the metal temperature change rate and temperature difference control curves of the mainframe. 4) Take note of the variation of the steam temperature and pressure, coal pulverizer as the unit load increases and reduces; and adjust the air volume and furnace draft in time; 5) Prepare in advance for convenient and timely stop and startup when coal pulverizer and other devices in the process of load increase and reduction needs to be stopped or started; 6) Manually adjust the automatic regulating equipment that is out of service for failure as required in the process of load variation, so as to keep it stably operating; 7) Monitor every water level and temperature and make sure them in normal range, so as to make them fit the load variation of the unit. 2.3.2.2 Main steam pressure adjustment 1) Maintain the main steam pressure of the steam turbine in normal operation at steam turbine follow mode by regulating the opening of the control valve; 2) Keep the main steam pressure invariable at the boiler follow mode by changing the combustion rate of the boiler; 3) Control the unit load and main steam pressure in combination of the steam turbine and the boiler in coordinate mode of the boiler follow mode; 4) Before performing manual and automatic switching, try to keep the actual pressure accord with the automatic set value first; while altering the main steam pressure, the set value is not suitable for being changed largely, largely, i.e. not exceeding 0.2MPa/min at a time; 5) Keep the main steam pressure within 17.47±0.2MPa when the unit operates normally under the rated condition; fuel quantity control method is allowable for the steam adjustment except of the approach to affecting on the stable combustion; 6）The application of safety valve for steam depressurization under non-accident condition is forbidden. In case of happening excessive pressure of the boiler, the EBV should be opened first.
2.3.3 Varying duty operational limitation of the unit 2.3.3.1 Allowable variation range of the main and reheat steam pressure and temperature and allowable continuous operating time thereof under abnormal condition
Parameter Name Main steam Average pressure in any 12-month cycle pressure
Allowable deviation value in case of maintaining the average pressure
123
Limit Value ≤1.00Po ≤1.05Po
Allowable deviation value in exceptional case, but the accumulative time in 12-month cycle must be
≤1.2Po
less than 12h Cold reheat steam pressure
≤1.25Pr
Average temperature in any 12-month cycle Allowable deviation value in case of maintaining the average temperature
≤538℃ ≤538+8℃
Allowable deviation value in exceptional case, but Main
and
reheat steam temperature
the accumulative time in 12-month cycle must be
≤538+(8～14)℃
less than or equal to 400h Allowable deviation value for less than or equal to 15min in exceptional case, but the accumulative time in 12-month cycle must be less than or eq ual to
≤538+(14～28)℃
80h Not
Unallowable value
exceeding
538+28℃
Note: Po and Pr in the table are rated pressure of the main and reheat steam; T stands for rated temperature of the main steam or the reheat steam. 2.3.3.2 Possible operating conditions capable of being borne by the steam turbine, comprising: 1) Its shat system is able to bear the moment of torsion resulting from abrupt short-circuit with any from of the generator outlet busbar or bidirectional reclosing or asynchronous closing 2) Idle runtime for the steam turbine after the load rejection is not less than 15min and not allowed to exceed speed. 3) The steam turbine is able to operate without load at rated speed. And the allowable duration must meet the requirements of the generator test. 4) Longer-ter Longer-term m operation operation for for the steam steam turbine turbine at at the exhaust exhaust tempera temperature ture below below 65℃ is allowable allowable as well well as low-loa low-load d continuous continuous operatio operation n at the temperat temperature ure not exceeding exceeding 79℃ . It is also able able to operate operate in a short short term term for for 15min 15min at the the temperatur temperature e not exceedin exceeding g 107℃ . 5) The steam turbine peak is allowed to be ranged from 60MW to 600MW. 6) The unit is able to safely operate at the back pressure up to 18.6KPa under abnormal condition. 7) The steam turbine is able to adapt to the variation of 50% rated load and the unit has the function of RB. 8) The unit is able to constantly operate stably at a cyclic wave ranging from 48.55Hz to 50.5Hz. 9) The turbo-generating set is able to automatically control the turbine rotating speed to prevent the unit from tripping and decelerate to a synchronous revolution when the steam turbine load is rejected from 100% to zero. 10) The unit is allowed to constantly operate with a rated load as the exhaust pressure rises to 124
13.3KPa. 11) The steam turbine at least has the ability of operating for 1min without steam within the range from normal back pressure to the alarm back pressure as the generator is still synchronized to the grid and the main stop valve is abruptly closed so that any damage to the devices can be avoided. 12) The turbo-generating set is able to stably operate at the load range from the TMCR to the minimum load in accord with the boiler. Hybrid variable pressure operation for the unit is applied. The sliding pressure operation for the steam turbine is ranged from 3 0%THA to 90%THA. 3. Normal Shutdown of Unit 3.1 Preparations before Shutdown 3.1.1 After receiving the command of preparing for stop, the duty director informs of the coal, ash and chemical control personnel about the predicated unused time and schedule, and the requirements of well preparation for the outage and enough oil reserve in the oil bunker that can meet the needs of the boiler outage. 3.1.2 Contact the duty director for replacing the auxiliary steam supply with adjacent steam or startup steam supply; 3.1.3 Give a trial run for the mainframe AC auxiliary oil pump, mainframe DC emergency oil pump, AC startup oil pump, jacking oil pump and turning gear motor to confirm they are normal and automatic. If the trial run is unqualified under non-failure outage condition, hold down till solving the causes; 3.1.4 Confirm the DEH control system is a t AUTO AUTO mode; 3.1.5 Select the smaller load decreasing rate (not greater than 15MW/min) between the “sliding pressure outage curves” allowable rate and the boiler allowable rate as the loading limit of the unit; 3.1.6 Make an overall copy of the steam and metal temperatures once, and then copy them per hour at the beginning of load reduction and in the process of the load reduction till normal outage of the mainframe turning gear; 3.1.7 Completely check all devices once and record their defects. 3.2 Shutdown with Variable Parameter 3.2.1 Shutdown with variable parameter is usually applied to the normal shutdown of the unit. 3.2.2 After receiving the variable-parameter shutdown command, the duty director begins to reduce thermal load of the boiler, and lower the temperature and depressurize according to the requirements of the variable parameter shutdown curves. 3.2.3 The unit loads from 600MW to 540MW; 3.2.3.1 Constant pressure operating mode is applied as the load of the unit is between 600MW 125
and 540MW; 3.2.3.2 Maintain the main steam pressure at the rated steam pressure; slowly reduce the boiler fuel quantity; gradually reduce the load command of the steam turbine and control the load variation rate not greater than 15MW/min. 3.2.4 The unit loads from 540MW to 300MW; 3.2.4.1 Sliding pressure operating mode is applied as the unit load is ranged from 540MW to 180MW; 3.2.4.2 Maintain the turbine load command invariable; control the load variation rate not greater than 15MW/min and the main steam pressure variation rate not greater than 0.446MPa/min; maintain the main and reheat steam temperature at the rated parameter; slowly reduce the combustion rate of the boiler. The unit load reduces with the main steam pressure drop till the target pressure 10MPa; 3.2.4.3 While loading to 360MW, check the mainframe gland steam pressure, i.e. make sure it is normal and take note of the switchover of the gland steam source; 3.2.4.4 While loading to 300MW, start up a motor-driven pump and stop a turbo-feed pump after the motor-driven pump operates normally. 3.2.5 The unit loads from 300MW to 180MW; 3.2.5.1 Sliding pressure operating mode is applied as the unit load is ranged from 300MW to 180MW; 3.2.5.2 Maintain the turbine load command invariable; control the load variation rate not greater than 9MW/min and the main steam pressure variation rate not greater than 0.1MPa/min; 3.2.5.3 Reduce the load to 180MW, main steam pressure 8.62MPa, reheat steam pressure about 1.0MPa, main main steam steam temp temper eratu ature re 525 525℃ and and rehe reheat at stea steam m tem temper perat atur ure e 520 520℃ ; 3.2.5.4As loading to 180MW, check the HP section drain valve of the steam system and confirm it is open; 3.2.5.5 Stop a water circulating pump or adjust the operating mode of circulating water according to the vacuum condition; 3.2.5.6 Keep the load stable and the main steam pressure invariable, lower the temperature of the steam turbine turbine to cool; cool; lower lower the main main steam steam temperatur temperature e to the target target temper temperature ature 420 420℃ with a rate of temperature temperature drop drop not greater greater than than 1℃ /min and and the reheat reheat steam steam temperatur temperature e to the target target temp temper eratu ature re 355 355℃ with with a rat rate e of tem tempe pera ra rue rue dro drop p not not grea greate terr than than 1.5 1.5℃ /min /min.. 3.2.6 The unit loads from 180MW to 60MW; 3.2.6.1 Constant pressure operating mode is applied as the unit load is ranged from 180MW to 60MW; 3.2.6.2 Contact the duty director for preparing disconnection; 3.2.6.3 Continue to reduce the load of the unit with the variation rate not greater than 6MW/min; lower the temperature and maintain the main steam pressure at 8.62MPa; 3.2.6.4 Gradually reduce the load of the second turbo-feed pump and pay attention to track the 126
output of the motor-driven pump, i.e. make sure it is normal; stop the second turbo-feed pump, take not of its steam drum water level, i.e. make sure it is normal and switch the control mode of the water level to single impulse control; 3.2.6.5 With 120MW load, alter the fourth extraction steam supply for the deaerator to the auxiliary steam header supply; 3.2.6.6 With 120MW load, check the IP section drain valve of the steam system and confirm it is open; 3.2.6.7 Check the LP cylinder of the steam turbine, i.e. make sure it is automatically put into operation operation and maintain maintain its its exhaust exhaust temperature temperature not greater greater than 50 50℃ ; 3.2.6.8 Stop the steam sides of the HP and LP heaters while paying attention to its water level variations; 3.2.6.9 With 60MW load, start up the TOP and MSP, make sure they are normal; check the LP section drain valve of the steam system, i.e. make sure it is open; 3.2.6.11 The unit load falls to 60MW; 3.2.6.12 Contact the duty director for preparing steam turbine shutdown by tripping; 3.2.6.13
Press the TURBO TURBO TRIP button on the control panel or locally locally manual trip; trip; check the IP
main stop valve, HIP control valve, every stage of extraction check valve, HP cylinder exhaust check valve, i.e. make sure they are closed and tight; confirm the V.V and BDV are open. And the rotating speed trends to slow down. 3.2.7 Generator disconnection 3.3 Operations after Generator Disconnection
3.3.1 Turbine operations after generator disconnection 3.3.1.1 Note that the rotating speed of the steam turbine begins to slow down after tripping; record the idle runtime; note the lube oil pressure and temperature, i.e. make sure they are normal; 3.3.1.2 Adjust or close the HP and LP bypass valves based on actual conditions; 3.3.1.3 As the rotating speed reaches 2500r/min, check the jacking oil pump and make sure it is automatically started; otherwise, manually start one; check the jacking oil manifold pressure and the jacking oil pressure of every bearing, i.e. make sure they are normal; 3.3.1.4 Check the turbine back cylinder water spray valve, i.e. make sure it acts normally and the LP cylin cylinder der exhau exhaust st tempe temperat rature ure less less than than or equal equal to to 47℃ ; 3.3.1.5 As the rotating speed is zero, check and confirm the turning gear is automatically meshed; otherwise, manually put it into operation; after the mainframe turning gear is put into operation, regularly record the rotor eccentricity, HIP cylinder expansion, differential expansion, HIP cylinder primary temperature and axial displacement etc.; 3.3.1.6 As the rotating speed reaches zero, it is able to stop the MSP; 3.3.1.7 Close the drain valve of the main steam pipe till the boiler pressure is relieved to zero; 3.3.1.8 After the unit flames out, confirm the bypass system is out of service, there is no steam but 127
having pressurized drain water entering the condenser; stop the condenser and open the vacuum break valves of the HP and LP condensers; 3.3.1.9 As the condenser vacuum is pumped out fully, stop the gland sealing system; 3.3.1.10 Stop the EH oil pump and maintain the EH oil circulating system in operation as required; 3.3.1.11 Cut off the condensate polishing unit; 3.3.1.12 Stop the motor cooling water system and reversely flush the stator with cooling water as required; 3.3.1.13 As the boiler is completely unnecessary for feeding water, stop the deaerator heating and the motor-driven feed pump; 3.3.1.14 As the steam drum pressure approximates to zero, the LP cylinder exhaust temperature of the the steam steam turb turbine ine is is below below 50℃ and no no high high temper temperatu ature re steam and water enters into the condenser. Stop the other water circulating pump and note to adjust the temperature of every auxiliary operating device; 3.3.1.15 Stop the condensate pump as there is no user for the condensate; 3.3.1.16 Stop the turning gear as the highest cylinder temperature of the steam turbine is below 150℃; stop the the jacki jacking ng oil pump pump afte afterr the roto rotorr is stati static; c; 3.3.1.17 Gas displacement for the generator is generally performed after the mainframe continuous turning is stopped. Closely monitor the oil level variation of the sealing oil tank during gas displamcnet to prevent oil from entering the generator; 3.3.1.18 Stop the sealing oil system after the completetion of the gas displacmnt and steam turbine turning; 3.3.1.19 Stop the mainframe lubricating oil system and the purification plant after the highest metal temp temper erat atur ure e is belo below w 120 120℃ ; 3.3.1.20 Get maintenance and isolation work done after stop. 3.4 Cautions for Unit Shutdown 3.4.1 Temperature and pressure of the steam turbine and boiler during the variable parameter shutdown of the unit should be coordinated reduced without rising again. It must closely note of the variation of the main stop steam pressure, te mperature, and furnace pressure and steam drum water level while stopping the coal pulverizer. Take not of falling speed of the steam temperature and steam cylinder wall temperature; that is, the falling speed of the steam temperature must strictly meet the requirement of the variable parameter shutdown curves and the steam cylinder wall temperature difference is within the allowable range. 3.4.2 During the variable parameter shutdown, it must strengthen the supervision to the main steam parame parameter ter,, especially especially the the degree of of superheat superheat greater greater than than 56℃ . If the steam steam temperat temperature ure sharpl sharply y drops drops to 50 50℃ in 10min 10min,, trip trip to stop stop immedi immediatel ately y. 3.4.3 During the variable parameter shutdown, the falling speed of the reheat steam temperature should follow that of the main steam temperature as much as possible. The temperature departure 128
of the main and reheat steam should meet the requirements of the main, reheat steam temperature departure curves; othe rwise, trip to stop immediately. immediately. 3.4.4 During the variable parameter shutdown, the steam parameter variation should be controlled to make the metal temperature variation and difference of very part of the steam turbine proper meet the requirements of the metal temperature change rate and difference curves. Otherwise, suspend further reducing the parameter and load to moderate the temperature difference and thermal stress of the metal parts. 3.4.5 Closely monitor the unit vibration, axial displacement, thrust pad temperature and differential expansion etc., i.e. make sure they are normal; as reaching the alarm value, stop the variable parameter shutdown mode and adjust the parameter to normal. 3.4.6 During the load reduction of the steam turbine, note that there is no jam occurred at the HP and IP control valves and the water levels of the deaerator, condenser and heate r are normal. 3.4.7 In low load operation, it is necessary for closing the normal drain valve in order to avoid steam from returning between the heaters resulting from insufficient pressure difference. And the emergency drain valve can be used for maintaining the heaters water level in normal operation. 3.4.8 Try to avoid the unit from long-term operating on 180MW load, fast reduce the active power to 15MW as it loads to 60MW, disconnect the generator-transformer unit as the reactive power of the generator reaches 5MVar; manually trip the steam turbine, che ck the HIP main stop valve, HIP control valve, every-stage extraction check valve, HP cylinder exhaust check valve, i.e. make sure they are closed and check the V.V and BDV, BDV, i.e. make sure they are open. 3.4.9 Note that the rotating speed of the steam turbine is to reduce after tripping, but opening the vacuum break valve at the rotating speed above 2000r/min in unexceptional case is forbidden. 3.4.10 3.4.10 Duri During ng the the turni turning, ng, keep keep the lube lube oil oil tempe temperat rature ure rangin ranging g from from 27 27℃ to 40℃ and mainta maintain in the sealing oil system of the motor operating normally; regularly listen carefully sound of the HLP gland. 3.4.11 Stop turning the mainframe when the turning gear continuously operates till the maximum cylinder cylinder temperatur temperature e of the steam steam turbine turbine is less less than 150℃ as well as the lubricati lubricating ng oil system; system; and note that the sealing oil system is in normal operation. 3.4.12 Do not overhaul the systems associated with the steam turbine proper during turning after shutdown; prevent the cold steam and water from entering the steam turbine; note monitoring the cylinder metal temperature variation tendency of the steam turbine. Every drain valve can be operated according to following requirements: 3.4.12.1 In case of outage maintenance of the unit and without special requirement, the drain valve and loop pipe drain valve directly connected with the cylinder are not opened before the cyli cylind nder er tem temper perat atur ure e is dow down n to 150 150℃ . 3.4.12.2 After shutdown, it should take note of the temperature differences of the upper and lower cylinders, the upper and lower temperature differences of main, reheat steam pipes and every extraction steam pipes, and water level, pressure and temperature variation of every water 129
container; if the temperature differences of the cylinders are sharply increased, it should find out the causes of entering water or feeding cold steam immediately, cut off the water and steam, and drain the water. 3.4.13 During the turning period, the principles of stopping continuously turning or stopping for turning gear failure in need of work are as follows: 3.4.13.1 In case the turning gear fails or it is actually necessary for stopping immediately for the purpose of overhaul, it needs to mark the rotator at corresponding position after stopping turning and memorize the stop time. 3.4.13.2 3.4.13.2 With the HP cylinder cylinder primary primary inner inner wall tempera temperature ture above above 350℃ , the stop time time of turning turning is not allowe allowed d to exceed exceed 3min. 3min. With With the temper temperatur ature e rangin ranging g from from 220 220℃ to 350 350℃ , the the stop stop time time will not exceed 30min. if the turning operation can not be completed during the period said above, reversely reversely rotate rotate the the rotor 350℃ at intervals intervals of the said said time, and and then continue continue to turn. 3.4.13.3 Rotate the rotor for 180°before continuous turning is available after its interruption; continue to turn after passing half of stop time; at this time, pay special attention to the rotor eccentricity and make sure the turning gear current does not excessively fluctuate. 3.4.13.4 During turning in special case, the jacking device can be stopped on the premise of monitoring the turning gear current. As the turning gear current increases not greater than 120% of the normal value, the jacking device can be stopped to continue to turn; otherwise, the jacking device must be put into turning. 3.4.13.5 During the continuous t urning, if there is apparent metal fricative sound in the cylinder and the turning gear current fluctuates by a large margin (but not turning gear failure), it must be stopped immediately. immediately. And shaft can be straightened by manual turning in accordance with the said principal till recovering continuous turning. 3.4.13.6 If the steam turbine rotor is locked, forced turning is not allowed. (The use of steam supply for the unit or crane rotation is available.) 3.4.13.7 If there is creepage caused by the malfunction of the jacking oil system, continuous turning must be stopped while the phenomena can not be removed after reducing oil temperature (not less less than than 27℃) by additiona additionally lly starting starting the DC lube oil pump. Maintain Maintain the the rotator rotator straightening by rotating it for 180°at every 10min till the continuous turning is reset but without creepage phenomena.
3.5 Regular work for steam turbine
No.
Date
1
once per shift
2
once per shift
Content
shift
Thermal signal test
Requirement
shift time lighting and sound are normal
Local remote calibration of drum, deaerator, working condenser water level gauge
130
time
conformity
3
once per shift
4
once per day
5
once per day
6
once per day
7
Each Monday
8
Each Tuesday
9
Each Wednesday
10
Each Thursday
11
Each Friday
Instrument use gas source tank drainage
time Filter discharge of the circulating pump inlet
first month of each
Handle rotation of the sealed oil system filter
13
of the filter before and after
night shift
Activity test of the main tank oil level gauge
night shift
Instrument use air compressor switch Rubber ball cleaning
no jam, alarm is normal
day shift night shift
Activity test of the Activity
test
high-pressure main valve day da y shift local monitoring is normal
of
the
medium-pressure
adjustment valve Activity test of the extraction control valve high-pressure
main valve
day shift shift local monitor monitoring ing is normal normal day shift slight adjustment man on duty
quarter first Monday of the
middle inspect the water level difference shift
first Monday of the All-process activity test of o f the 12
working
Injection test
second month of
day shift shift test after after on-site on-site confirm confirm and lock lock
each quarter 14 15
Circulating pump switch
2
12
22
day shift
Stator cooling water pump switch
middle shift
Main oil pump switch of A, B small machine, 16
DC oil pump start-up test
5
15
night shift
25
DC
oil
pump
should
continuously run for more than 10min
Oil pump switch of A / B side of air preheater middle Oil pump switch of A / B side of air
17
18
guide bearing
shift
Vacuum pump switch
night shift
The main seal oil pump switch, DC seal oil 19
The
6
16
26
pump start-up test
preheater guide bearing Start pre-test insulation The
DC
oil
pump
should
day shift continuously run for more than 10min
Seal oil filter discharge
20
night shift
8
18
28
Open-pump switch 131
note for the seal oil pressure
shift 22
EH oil pump linkage test and switch
day shift
Axis plus fan switch
23
middle shift
Seal fan switch
24
night shift
Open-loop water filter discharge
middle
25
11
26
12
27
13
28
14
29
16
30
18
31
19
32
20
MSP, MSP, TOP, TOP, EOP linkage test
day shift EOP should run more than 30min
33
25
Oil cooler switch of the big machine
day shift
34
26
Vacuum tightness test
day shift
35
Irregular
shift Main tripping tripping solenoid solenoid valve movement movement test Activity test of the
high and low pressure
main valve of o f A small machine Activity test of the
high and low pressure
main valve of B small machine Condensate pump start-up test
day shift normal normal action day day shif shiftt No jam jam
day day shif shiftt No jam jam middle shift
Vacuum tightness test All-process
activity
day shift test
of
the
main
medium-pressure valve
Hydrogen desiccant device, seal oil vacuum pump drain water
132
day shift shift local monitor monitoring ing is normal normal
Implement with water
Chapter Ⅳ Accident Management of Unit 1. General Principles 1.1 The operator shall handle failures in strict accordance with the operational procedure as those failures occur. The duty director and the attendant shall process those special failures out of the procedure range according to the operating knowledge and experience under the principal of ensuring the safety of person and devices. 1.2 As the failures occur, the operator should quickly lift personal and devices out of danger and find out the causes in time and solve them. They must guarantee the station auxiliary power system in normal operation and keep the non-failure devices in operation. 1.3 Procedures for removing failures are as follows: 1.3.1 No matter what failures are occurring in the unit, the operator should quickly and carefully confirm the character, development tendency and hazard degree, and then take correspondingly measures. 1.3.2 While the failure occurs, there is corresponding acousto-optic alarm displayed on the turning gear and MMI, and so the operator should confirm and take corresponding measures. 1.3.3 It must quickly lift the personnel and devices out of danger and disconnect the failed devices immediately if necessary, necessary, so as to maintain the non-failure devices in normal operation. 1.3.4 No matter what failures are occurred, it must check the indication or status of the meters and confirm it in site if necessary. 1.3.5 Each stage for removing the failure must report to the duty director and associated leaders as fast as possible so as to timely and correctly take adequate measures to prevent the accident from widely spreading. 1.3.6 As the failure occurs, the operators in charge of every position must quickly handle the failure under the unified command of the duty director in close coordination, so as to recover normal operation of the unit as fast as possible. 1.3.7 Removing the failure must be quick and correct. The operators must repeat the command after receiving it. If it is unclear, the operators must make it clear. After completing, they must report to the commander as fast as possible. 1.4 Relevant leaders and full-time engineers must arrive in site as soon as possible to assist to handle failures as the unit failure occurs and give necessary instruction to the operator on the premise of subjecting to the command of the duty director d irector.. 1.5 At the moment of failure occurrence and processing, the operator must stick to his post. If the failure occurs at the time of handover, it should be delayed. Before the handover, the operator must keep working and the operator on duty must remove the accident in coordination with the operator till the unit recovers normal operation. 133
1.6 The person unrelated with the accident treatment is forbidden staying at the position of fault. 1.7 After removing the fault, the duty director and operator on duty must correctly record the process and time of fault occurrence and measures for removing the fault etc. in detail, and report to every stage of schedulers and leaders in time. 1.8 During the accident treatment, operation order can be unused, but relevant manual are required to be complied.
2. Manual on the Handling of Unit Accidents 2.1 Emergency Outage Conditions of Unit 2.1.1 In case there is accident that endangers the person and devices, the unit shall be shut down immediately; 2.1.2 Vacuum break break and emergency shutdown of the steam turbine shall be operated un der one of following conditions: 2.1.2.1 The steam turbine is over-speed with the rotating speed greater than or equal to 3330r/min and the emergency governor is failed to actuate; 2.1.2.2 The generating set of the steam turbine has suddenly severe vibration with the bearing vibration greater than or equal to 0.25mm, and the protection is failed to operate; 2.1.2.3 The axial displacement of the rotor is greater than or equal to 1.2mm or less than or equal to negative 1.65mm, and the protection is failed to operate; 2.1.2.4 The time delays for 2s as the unit load is greater than or equal to 50% and the main steam temperature temperature is is lower than 474℃ ; it is to to alarm as the load load is less less than 50% 50% and the main main steam steam temper temperatu ature re is is less less than than 490 490℃, and and 2s delay delay is is requi required red as the the tempe temperat rature ure is redu reduced ced to 460 460℃ . The protection is failed to operate; 2.1.2.5 There is apparent metal friction or impact sound inside the generating set of the steam turbine; 2.1.2.6 Oil level in the main lube oil tank falls sharply and o il make-up is unavailable; 2.1.2.7 There is water attack occurred in the steam turbine. Upper and lower temperature differences differences of the inner inner cylinder cylinder of the HIP HIP cylinder cylinder reaches reaches 55.6 55.6℃ or main main steam tempera temperature ture decr decrea ease ses s by by 50 50℃ in 10mi 10min; n; 2.1.2.8 The thrust thrust pad metal metal temperat temperature ure is greater greater than than or equal equal to 110 110℃ and lasts lasts for 2s. 2s. The protection is failed to operate; 2.1.2.9Metal 2.1.2.9Metal temperature temperature of any any bearing bearing of the steam steam turbine turbine rises to to following following values: values: 115 115℃ of #1-# #1-#6 6 jou journ rnal al bear bearin ings gs,, 105 105℃ of #7-#9 jour journal nal bear bearing ings s and 110 110℃ of thrus thrustt bearin bearing. g. The The protection is failed to operate; 2.1.2.10 The HIP differential expansion is less than negative 6.6mm or greater than 11.6mm; the LP differential expansion is less than negative 8. 0mm or greater than 30mm; 134
2.1.2.11 Return oil temperature of any bearing of the steam turbine exceeds the limit or it reeks and lacks of oil; 2.1.2.12 The turbine gland sparkles resulting from abnormal friction; 2.1.2.14 The generator reeks and catches fire or the hydrogen system blasts; 2.1.2.15 The generator slip ring and carbon brush seriously sparkle and are unable to extinguish; 2.1.2.16 The turbine oil system is on fire and unable to be extinguished quickly, so as to severely threats safe operation of the unit; 2.1.2.17 The lube oil pressure continues to drop in case an auxiliary lube oil pump is started up after the lube oil is cut off or the pressure drops to 0.103 MPa. 2.1.3 Vacuum break to emergency shutdown is required under one of following conditions: 2.1.3.1 The steam pipe and the water pipe are unable to keep normal operation resulting from high pressure and broken pressure part, respectively; 2.1.3.2 The safety valve is failed to operate as the b oiler pressure boosts up to the action pressure of the valve; 2.1.3.3 One of the main and reheat steam temperature rises to 552～564 564℃ at rate rated d pre press ssur ure e for for excess excessive ive 15mi 15min n contin continues ues oper operati ation on or exce exceeds eds 564 564℃ ; 2.1.3.4 The stator coil of the generator is cut off cooling water supply and unable to resume the water caused by inactive protection; or the cooling water temperature rises to 78 ℃ and is unable to be reduced with the load reduction; 2.1.3.5 The protection is failed to operate as the unit reaches the action value; 2.1.3.6 The steam turbine operates over 1min without steam; 2.1.3.7 The condenser vacuum drops to negative 77.5KPa and is unable to recovery as the load drops to zero; 2.1.3.8 The unit is unable to control its rotating speed or load resulting from abnormal operation of the DEH; 2.1.3.9 The EH oil pump and EH system failure endangers the safe operation of the unit; 2.1.3.10 All sealing oil pumps are failed and sealing oil is supplied by the main lube oil pump only; 2.1.3.11 The operating supervisory meters of the steam turbine, especially the speed indicator, indicate incorrectly or invalidly, and there are no other effective measures instead of these meters; 2.1.3.12 The main transformer, high voltage auxiliary transformer and excitation transformer catch fire or smoke; 2.1.3.13 The severe water leakage of the generator body e ndangers safe operation of the devices; 2.1.3.14 Hydrogen purity in the generator drops quickly below 92%; 2.1.3.15 2.1.3.15 A/B LP cylinders cylinders exhaust temperature temperature is is greater greater than or equal to 107 107℃ and the protecti protection on is failed to operate; 2.1.3.16 2.1.3.16 The exhaust exhaust pipe pipe metal temperature temperature of of the HP cylinder cylinder rises and exceeds exceeds 432℃ ; and the protection is failed to operate; 2.1.3.17 The turbine room on fire endangers the safe operation of the unit. 135
2.1.4 Emergency shutdown treatment of the unit 2.1.4.1 Stop the unit by pressing corresponding EMERGENCY TRIP button in case of meeting any emergency shutdown condition of the steam turbine, boiler and generator; 2.1.4.2 Check the interlocks of the boiler, steam turbine and generator, i.e. make sure they acts correctly; confirm the boiler fuel are totally cut off, the HP and IP main stop valves and control valves are closed tightly and the rotating speed of the steam turbine drops rapidly; break the steam turbine vacuum as required; 2.1.4.3 Confirm the station auxiliary power system switches over normally; otherwise, replace it with manual switchover; 2.1.4.4 Check the AC auxiliary oil pump, startup oil pump and jacking oil pump, i.e. make sure they are automatically started; otherwise, manually start them immediately; check the sealing oil system of the generator, i.e. make sure they are operating normally; 2.1.4.5 Note the idle condition, differential expansion, vibrating, axial displacement, cylinder expansion and upper and lower temperature difference etc. of the steam turbine; listen the sound generated inside of the steam turbine, i.e. make sure it is normal; 2.1.4.6 Make sure the turning gear is to automatically operate as the rotating speed of the steam turbine is zero; check the oil pressure and temperature, and turning gear current, i.e. make sure they are normal; 2.1.4.7 Change the gland steam supply fast to auxiliary steam supply after the unit trips; regulate the gland steam pressure in time; stop supply the gland steam as the vacuum reaches zero; isolate the gland attemperating water; 2.1.4.8 Check the relevant water prevention valves of the steam turbine i.e. make sure they are automatically open; otherwise, manually open them; 2.1.4.9 Check whether the cooling water of the drain flash tank is automatically put into operation; otherwise, manually put it into operation; 2.1.4.10 Check whether the water levels of the condenser and the deaerator are automatically and normally adjusted; otherwise, manually adjust to keep them normal; 2.1.4.11 Check the lube oil temperature, sealing oil temperature, generator hydrogen temperature and stator cooling water temperature of the mainframe, i.e. make sure they are normal; adjust them if necessary; 2.1.4.12 Check the LP cylinder, i.e. make sure its water spray function is normally put into operation; 2.1.4.13 As it is on fire or hydrogen explosion occurs inside of the steam turbine, extinguish the fire with carbon dioxide and discharge the hydrogen; in case idle speed of the rotator approximates to 200r/min, close the vacuum break valve till the creation of vacuum and try to maintain the rotating speed till extinguishing the fire; 2.1.4.14 Close the main steam drain valve; 2.1.4.15 In case the induced and forced draft fans do not trip, total blast volume of the boiler must 136
be adjusted to that under 25-30%BMCR 25 -30%BMCR to purge for 5min. Otherwise, they are started to purge for the furnace after opening the air-flume system baffle plate for naturally ventilate for 15min. If it will not be ignited in a short-time, Stop the fans after purging, and then superheat the boiler; 2.1.4.16 Complete other normal shutdown operations of the unit; 2.1.4.17 Report the failure conditions to the dispatcher and relevant leader; 2.1.4.18 Copy relevant curves and emergency records; keep them well; and carefully record the emergency conditions; 2.1.5 Emergency shutdown operating procedures by breaking vacuum: 2.1.5.1 Press the EMERGENCY SHUTDOWN button on the control panel or disconnect the turbine trip handle at the turbine head by hand; confirm the TURBO TRIP lamp is on, the unit load reaches zero, the generator is disconnected, the auxiliary power is changed successfully ; Check the HP and IP main stop valves and control valves, every extraction electric valve and check valve, and HP cylinder exhaust check valve, i.e. make sure they are closed; check the HP cylinder exhaust vent valve, HIP cylinder emergency dump valve, i.e. make sure they are opened; make sure the rotating speed of the steam turbine continuously drops; 2.1.5.2 Check the AC lube oil pump and the startup oil pump, i.e. make sure they are started successfully; make sure the lube oil pressure is normal; 2.1.5.3 Check the relevant water prevention valves of the steam turbine i.e. make sure they are automatically open; otherwise, manually open them; 2.1.5.4 Confirm the jacking oil pump automatically starts as the rotating speed of the steam turbine drops to 2500 r/min; release the vacuum pump interlock, stop the vacuum pump and open the condensers A/B vacuum break valves as the rotating speed drops to 2000r/min; 2.1.5.5 Check whether the HP and LP bypass valves work, if they are opened, manually close them immediately; 2.1.5.6 Close the drain valves on the main, reheat steam pipes; if the circulating water is cut off, close all drain water supply to the condenser; 2.1.5.7 Check the turbo-feed pumps A/B and confirm they are triggered to trip; check the motor-driven feed pump, i.e. make sure they are jointly started normally; 2.1.5.8 Check that the fourth steam extraction user is normally switched to the auxiliary steam supply and the gland steam is automatically and normally switched; 2.1.5.9 Check the water levels of the condenser and the deaerat or, i.e. keep them in normal range; 2.1.5.10 Check that the LP cylinder spray valve is automatically opened and adjust the exhaust temperature within normal range; 2.1.5.11 Stop Stop the gland sea ling system as the vacuum is zero; 2.1.5.12 completely check and listen carefully the sound inside of the unit while the rotating speed drops; 2.1.5.13 Put the turning gear into operation while the rotating speed is zero, and record the idle time and rotor eccentricity; 137
2.1.5.14 Complete other operations relevant with normal shutdown. 2.1.6 Operating procedures for emergency shutdown on the premise of keeping original vacuum: 2.1.6.1 Press the EMERGENCY SHUTDOWN button on the control panel or disconnect the turbine trip handle at the turbine head by hand; confirm the TURBO TRIP lamp is on, the unit load reaches zero, the generator is disconnected, the auxiliary power is changed successfully and the rotating speed of the steam turbine continues to reduce; 2.1.6.2 Check the HP and IP main stop valves and control valves, every extraction electric valve and check valve, and HP cylinder exhaust check valve, i.e. make sure they are closed; check the HP cylinder exhaust vent valve, HIP cylinder emergency dump valve, i.e. make sure they are opened; 2.1.6.3 Check the AC lube oil pump and the startup oil pump, i.e. make sure they are started successfully; make sure the lube oil p ressure is normal; 2.1.6.4 Check and confirm the HP and LP bypass valves are automatically opened; 2.1.6.5 Check and confirm the corresponding drain valves are opened; 2.1.6.6 Check and start up the motor-driven feed pump, and confirm it is operating normally; 2.1.6.7 Check the turbo-feed pumps A/B, i.e. make sure they trip and put the turning gear into continuous operation; 2.1.6.8 Check and adjust the water levels of the condenser and the deaerator, and keep them normal; 2.1.6.9 Check and adjust the LP cylinder spray valve and drain flash tank spray valve, and make sure they are able to automatically open; 2.1.6.10 Check and adjust the gland steam pressure, and keep it within normal range; 2.1.6.11 Completely check and listen carefully the sound inside of the unit while the rotating speed drops; 2.1.6.12 Put the turning gear into operation while the rotating speed is zero, and record the idle time and rotor eccentricity; 2.1.6.13 Complete other operations relevant with normal shutdown. 2.2 Fault Shutdown Conditions of Unit 2.2.1 Report to the dispatcher and chief engineer to apply for fault shutdown under following conditions: 2.2.2 Fault shutdown conditions 2.2.2.1 The main, reheat steam parameters exceed the specified value and are unable to be recovered in specified time; 2.2.2.2 The measures for preventing slow drop of the condenser vacuum are unavailable, even zero load; 2.2.2.3 The axial displacement approximates to the limit value and can not recovery after processing; 138
2.2.2.4 The upper and lower cylinders temperature differences of the HP and IP cylinders exceed the limit (50℃); 2.2.2.5 EH oil pipe rupture or low oil level in the EH oil tank makes oil make-up operation unavailable; 2.2.2.6 The DEH control system or HP and I P control valves are failed to maintain operating; 2.2.2.7 The major auxiliary is failed to maintain its operation; 2.2.2.8 The steam-water pipe is unable to work resulting from leakage; 2.2.2.9 The stator cooling water has electric conductivity as 9.9µS/cm or is cut off; or the generator stator coil leakage problem is unable to be solved; 2.2.2.10 The turbine lubricating oil system is failed to normally operate; 2.2.2.11 The adjustment for the abnormal steam exhaust temperature rise of the LP cylinder is unavailable; 2.2.2.12 The water quality of the condenser is deteriorated for serious leakage and isolation for half condenser is unavailable; 2.2.2.13 The idle time of the steam turbine exceeds 15min after load rejection of the generator; 2.2.2.14 The hydrogen temperature of the generator exceeds the limit resulting from hydrogen cooling system failure and the adjustment for it is ineffective; 2.2.2.15 Hydrogen leak of the generator enables hydrogen pressure maintenance to be failed; 2.2.2.16 Sealing oil system failure of the generator makes necessary oil pressure and level maintenance be failed; 2.2.2.17 The DEH, DCS and TSI failures leads to some important operating parameters of the steam turbine unable to be monitored and the normal operation of the steam turbine and its auxiliaries can not be maintained; 2.2.2.18 The generator slip ring and carbon brush seriously sparkle and are unable to extinguish. 2.2.3 Fault shutdown operations of the unit 2.2.3.1 In case any one of the fault shutdown conditions is met, it should be reported to the duty director and dispatcher, and asked for the leaders to apply for shutdown; 2.2.3.2 As the unit shuts down resulting from faults, quickly reduce load in prior to transforming auxiliary power; as the unit load is less than 150MW, start the MSP and the TOP; 2.2.3.3 Press down the EMERGENCY SHUTDOWN button by hand or locally latch the steam turbine handle by hand; check the HP and IP main stop valves and control valves, every extraction electric valves and check valves, i.e. make sure they are totally closed; confirm the generator is disconnected, the VV and BDV are opened, and the rotating speed of the steam turbine is decelerated as the unit load drops to zero; 2.2.3.4 Check that the HP and LP drain valves are automatically opened; note the mains team pressure and close the HP and LP bypass valves in time; 2.2.3.5 Close the drain valves of the main and reheat steam pipes; stop the vacuum pump; open the vacuum break valve; cut off drain water to the condenser completely in case of stopping 139
circulating water supply; 2.2.3.6 Check that the turbo-feed pumps A/B trip, and the motor-driven feed pump is able to be tandem driven normally; 2.2.3.7Check and make sure the fourth extraction steam for the user is able to be replaced by auxiliary steam supply normally; 2.2.3.8Check and make sure gland steam can be automatically and normally switched; 2.2.3.9Start a jacking oil pump as the unit rotating speed drops to 2500r/min and make sure its oil pressure is normal; 2.2.3.10 Stop gland steam supply as the vacuum is zero; 2.2.3.11As the rotating speed reaches zero, check whether the turning gear is automatically put into normal operation; if not, manually put it into operation; record the idle time and eccentricity of the rotor, turning gear current, cylinders temperature etc.; 2.2.3.12 Check the unit and listen the sound generated from the rotating parts of the steam turbine; in case there is apparent metal impact sound inside or rotor idle time is significantly shortened, immediate restarting of the unit is forbidden; 2.2.3.13Note that the vibration, axial displacement, differential expansion, lube oil pressure and temperature, sealing oil-hydrogen pressure difference and water levels of each heater are normal during shutdown of the unit; 2.2.3.14 Other operations are similar to that of the normal shutdown. Complete other operations according to the operational procedures. 2.3 Comprehensive Accident Management of Unit 2.3.1 Main Fuel Trip (MFT) of Boiler 2.3.1.1 MFT action presentations 1) Audible and visual alarm occurs, and TURBO TRIP and GENERATOR GENERATOR TRIP indicating lamps are on as MFT works; 2）The main stop valves and control valves of the steam turbine, main stop valves and control valves of the reheater, and steam extraction electric valves and check valves of the heater are closed. The main steam pipes drain valves of the steam turbine, drain valves of the steam turbine body and steam extraction pipes drain valves are opened; 3）The generator outlet and extraction switches trip, and auxiliary power supply is fast switched to reserve power supply; 4）The re-circulating water valve of the feed pump is automatically opened. 2.3.1.2 Principles of steam turbine side management 1）Confirm the steam turbine trips, rotating speed decelerates, the HP and IP main stop valves, control valves and extraction check valves are closed, relevant water prevention valves are opened, the BDV and VV are automatically opened; 2）Close the electric valve for switching the cold reheat steam to the auxiliary steam; confirm the 140
auxiliary steam pressure, gland pressure and turbine vacuum are normal; put the deaerator into hearing; 3）Confirm that the parameters of the steam turbine is normal as it is in idle operation, the jacking oil pump is automatically started as the rotating speed is 2000r/min, the turning gear is automatically meshed and its motor is automatically started as the rotating speed is zero, the current and eccentricity of the turning gear are normal; 4 ） Prepare for restart in case the faults are able to be removed fast or the protection malfunctions; 5）In case the unit is unstable to be started, it can be handled by the principal of normal shutdown. 2.3.1.3 Handling principles as MFT works 1) Every protection is required to be put into operation and any protection is forbidden to exit temporarily in the process of handling the MFT; MFT; 2) It must be tripped immediately in case the causes for MFT working are not found out or the unit is unable to be restarted for its apparent defects; 3) Note that the AC auxiliary oil pump and startup oil pump are automatically started; otherwise, manually start them; check that the oil pressure and temperature are normal; take note of the idle time of the steam turbine, in case of fast deceleration of its rotating speed, automatically start the jacking oil pump and put the turning gears of the steam turbine and small steam turbine into operation in time; 4) Open the drain valves of the steam turbine in time; check the exhaust steam temperatures, i.e. make sure they are within the range specified by the Operational Procedures; 5) Closely monitor the differential expansion, axial displacement, upper and lower cylinders temperature difference, vibration of every bearing and bearing shell temperature of the steam turbine in the entire process, i.e. make sure they are within the range specified by the Operational Procedures; otherwise, trip it.
2.3.2 Entire Auxiliary Power Failure
2.3.2.1 Symptoms 1) AC illuminating lamp is off and DC emergency illuminating lamp is on so that control room light becomes dimmed. 2) The MFT works, the steam turbine and gene rator trip. 3) Overall AC motors in operation stop, AC standby motors are not tandem driven and every current indicates to zero. The main and small steam turbines lube oil pump and DC sealing oil pump are automatically started. 4) The diesel generator is automatically started. 2.3.2.2 Causes 141
1) The unit is failed, meanwhile the standby transformer is failed or in outage state or 6kV busbar reserve power supply is failed to automatically operate; 2) The unit and power system are failed at the same time. 3) Working power supply and reserve power supply are failed at the same time. 2.3.2.3 Handling principles 1) After entire auxiliary power failure, it is required to check that the main and small steam turbines trip and rotating speed is reduced; otherwise, manually trip them; 2) Handling for the boiler is operated according to the principle that the MFT works; 3) Immediately check the DC lube oil pump and DC sealing oil pump of the main and small steam turbine and make sure they are operating normally; 4)
In case of auxiliary electricity loss, the handling for the steam turbine should be operated
according to the “emergency shutdown procedures by breaking vacuum”; pay attention to the lube oil pressure and temperature of the main and small steam turbines and metal temperature of every bearing; 5) In case the safety busbar loses electricity, it is required to regularly turn the main and small steam turbines till the busbar is electrified. And then Continuous turning is put into operation after straightening shaft according to specifications; 6) Close drain water isolation valve of the main steam pipe; check that the mainframe bypass valve is closed, otherwise close it by means of manually relieving oil pressure; 7) Open the mainframe vacuum break valve as the rotating speed of it is less than 2000r/min; 8) Pay attention to the condenser exhaust steam temperature; in case the temperature drops below 50℃, circulatin circulating g water pump for supplying supplying water water for the the condenser condenser is forbidden. forbidden. 9) In case of auxiliary power failure and the sea ling oil pump unable to be started, it must quickly discharge hydrogen for the generator, gen erator, so as to prevent from blasting for hydrogen leakage; 10) After the auxiliary power failure, the instrument air compressor of the steam turbine for power supply trips and the standby automatically starts so that the former one should be reset as fast as possible; 11) After the auxiliary power failure, the closed cooling water is cut off. It should monitor the variation of the lube oil temperature of the mainframe. The public closed cooling water user is replaced by adjacent steam turbine that is operating stably; 12) Release the interlocks of every auxiliary and exit the automatic adjustment; 13) After insolating or removing the trouble spot, gradually recovery the auxiliary power supply for every section; start the systems to prepare f or the thermal startup of the unit after recovering the auxiliary power p ower..
2.3.3 Electricity Loss of Uninterrupted Power Su pply (UPS) 2.3.3.1 Symptoms 1) Failure of two UPS failure for some reasons at the same time leads to output power supply 142
interruption. Electricity loss of the UPS busbar makes the FSSS lose electricity, electricity, the MFT, steam turbine and transformer trip, a ll transformers lose auxiliary power supply, and the OS and IS lose electricity. 2.3.6.2 Handling principles 1) Confirm the steam turbine and turbine-driven pump trip and the turbine rotating speed decelerates; 2）Stop the electric pump under the condition that there is no monitor on the water level of the steam drum; 3）Start the AC lube oil pump and startup oil pump of the mainframe on the CD immediately in emergency; send a person to the site to check whether they are operating normally; if the remote startup is failed, locally start the DC lube oil pump of the mainframe immediately and make sure it is operating normally, so as to prevent from burning the bearing liner for lacking of oil; meanwhile start the AC lube oil pump and the startup oil pump at the switch room. In case the jacking oil pumps of the main and small steam turbine are not started, they can be started in emergency at the switch room. Check whether the AC sealing oil pump is operating normally, if not, start the emergency sealing oil pump in time and stop the AC sealing oil pump to prevent the generator from leaking hydrogen; 4）Locally check that two sets of turbine-driven pump and main oil pump a re operating; start the standby main oil pumps and jacking oil pumps A/B; locally check that every oil pump are operating normally; if the safety power supply loses, locally start the DC oil pump of the turbine-driven pump at local control box of the DC oil pump of the small steam turbine; 5）Check that the steam turbine and its auxiliaries are normally operating; 6）Feed water for the boiler by the electric pump according to specifications after the UPS is recovered; if the steam drum is seriously lack of water, handle it with the principle of less water in the boiler.
2.3.4 Full Load Rejection of the Unit 2.3.4.1 Symptoms 1）The unit load reaches zero and its sound changes suddenly sudd enly.. 2）The steam turbine trips and the generator switch trips to alarm. 3）The main stop valves and governing stem valves are closed with a zero opening indication. The rotating speed decelerates after rising. 4）The steam extraction check valves and electric valves are closed. 5）The governing-stage pressure is zero. 6）The HP and LP bypass valves are opened. 7）The MFT works in case the load of the unit at that time is greater than 30%. 8）In case the MFT does not work after the unit trip, the steam pressure and temperature will rise sharply, sharply, the water level in the steam drum lowers first, and then rises and a solenoid soleno id relief valve 143
works. 2.3.7.2 Causes 1）The 220kV main transformer switch trips. 2）The steam turbine or electric trip protection works or malfunctions. 3）MFT works. 4）The operator trips by mistake. 2.3.7.3 Handling principles 1）In case of full load rejection of the unit, it is processed in accordance with the “emergency shutdown operating procedures without breaking the vacuum”. 2 ） If the rotating speed continuously accelerates after the full load rejection, it must be processed in accordance with the “emergency shutdown operating procedures by breaking the vacuum”. 3）If the electric protection works, it is processed in accordance with the “generator transformer unit trip procedures”. 4）In case the unit load before the load rejection is greate r than 30%, the MFT works. If the MFT does not work, manually operate op erate it and stop the boiler in emergency. emergency. 5）In case the unit load is less than 30% before the load rejection and the main stop valve of the steam turbine is closed resulting from generator transformer unit switch trip, the boiler is able to continuously operate while processing as follows: a) To keep the main steam pressure stable, the HP and LP bypass valves of the steam turbine automatically open; b) In case the main steam pressure continues to rising after opening the said valves, oil should be fed to support combustion. And the pulverizing system should be stopped to keep the combustion stable and the main steam pressure normal; c) Check that the rotating speed of t he motor-driven pump is normally governed and the water level of the steam drum is normal; d) In case the bypass valves of the steam turbine failure to operate on command, process it according to the principal that the MFT works; e) Loading speed is not greater than 15MW/min while recovering; f) The boiler should be stopped in case the unit trip causes are unclear and it can not be recovered in a short term; g) If the main fuel trips resulting from inappropriate adjustment in the process of treatment, process it according to the principal that the MFT works; h) If the protection works, it should find out the failure causes and inform of relevant person to check the associated professional treatment; start the unit after removing the failures or being approved by the deputy general manager( chief engineer); 6) Contact the duty director for recovering the operation of the unit if the failures are caused by miss operation of the operator ope rator.. 144
2.3.4 Partial Load Rejection of Unit (under RB condition) 2.3.4.1 RB occurs in case that single forced draft fan, induced draft fan, primary air fan and air preheater trip and the unit load is greater than the maximum allowable output of one the device; 2.3.4.2 RB occurs in case a feed pump trips and its standby is failed to be started jointly in 5s, and the unit load is greater than the maximum allowable output of one said pump; 2.3.4.3 RB occurs in case a coal pulverizer trips and the unit load is greater than the maximum allowable output of the machine in operation. 2.3.4.4 Steam turbine side handling after occurrence of RB 1）In case the operating mode of the unit is “coordinate control”, the target load is automatically switched to the maximum allowable output of the device causing the RB; 2） As the “coordinate control” mode is switched to “turbine following boiler” mode, the steam turbine is applied to controlling the main steam pressure; 3）Cut off AGC as RB occurs. 2.3.4.5 Following operations should be applied as automatic treatment is ineffective after the RB works: 1）Find out the causes that RB works; 2）Take not of the variation of water level and steam temperature and control them within normal range; 3）The unit resumes normal operation after removing the causes of RB.
2.3.5 DEH Failure 2.3.5.1 Symptoms 1) There is no any process display or reaction although there is the display on the DEH screen; 2) DEH screen loses; 3) The unit trip is possibly happened. 2.3.5.2 Causes 1) Mouse failure 2) Display, DEH software and hardware failure 3) Power loss of operator station 4) DEH power loss 2.3.5.3 Disposal principles 1) Inform the thermal technician to the scene in time to process the DEH failures; 2) Check that the OIS screen displays normally; 3) Report to the provincial transfer to exit AGC and to stop loading up or down; try to keep the operating mode of the unit invariable on the premise of without affecting the stable operation of the unit; 4) Strengthen the monitoring on the important parameters of the OIS and the local inspection to 145
keep the parameters stable; 5) Locally check that each steam valve is closed and front header rotating speed counter continues to reduce in case of unit trip; 6) Start every oil pump of the mainframe; open the HP cylinder vent valves and emergency dump valves; monitor the relevant parameters of the mainframe through the OS screen, i.e. make sure they are normal; 7) Complete the normal shutdown operations of the unit.
3. Abnormal Operation and Accident Management of Steam Turbine 3.1 Condenser Vacuum Drop 3.1.1 Symptoms 3.1.1.1 The condenser vacuum drops; exhaust and condensate temperature rises; 3.1.1.2 Alarm for low vacuum and high exhaust temperature; 3.1.1.3 The unit load reduces correspondingly under the conditions that the main steam flow, pressure and temperature, and valves opening are invariable; 3.1.2 Causes of vacuum slow drop 3.1.2.1 Vacuum system leak 3.1.2.2 Vacuum pump failure of abnormal cooling system of the vacuum pump 3.1.2.2 Pretty low gland steam pressure, abnormal gland vacuum and water level and blocked gland drain water 3.1.2.3 Reduced circulating water flow resulting from dirty and blocked condenser steel pipe or tube plate and secondary filter screen, circulating water system failure of miss operation and so on 3.1.2.4 Excessively high hot well water level 3.1.2.5 Miss operation of the vacuum system valves 3.1.2.6 The HP and LP bypass valves in pe n condition 3.1.2.7 The valve of the water induction prevention system in operation is opened by accident or the condenser heat load is excessive. 3.1.2.8 Pretty low water level of condensate make-up tank or broken water seal of multi-stage U pipe 3.1.3 Causes of vacuum sharp drop 3.1.3.1 Circulating water interruption 3.1.3.2 Gland steam interruption 3.1.3.3 Excessively high water level of the hot well till reaching the extraction opening 3.1.3.4 The vacuum break valve to be opened by error 3.1.3.5 Bypass system mis-operation 3.1.4 Disposal principle of vacuum drop 146
3.1.4.1 ；Confirm the vacuum drop by comparing it with the exhaust temperature while finding it; find out the causes quickly and take corresponding measures to treat it and report to the duty director; 3.1.4.2 As the condenser vacuum drops to negative 87.5KPa, the standby vacuum pump automatically starts, if it does not, manually start it; if the vacuum continues to drop, begin to reduce load. As the vacuum drops to negative 74.7KPa, the load is reduced to zero, and trip protection works, otherwise manually trip to stop; 3.1.4.3 Take Take close note to th e LP cylinder exhaust temperature in the process of vacuum drop; put the back cylinder spray valve of the LP cylinder into operation as the exhaust temperature rises to 50℃; as the temper temperatur ature e conti continue nues s to rise rise to 107℃ , the the prote protecti ction on work works s to trip, trip, other otherwis wise e manually trip it; 3.1.4.4 Take note of the operating and load conditions of the turbo-feed pump as vacuum drop; switch to the motor-driven pump operation if necessary; 3.1.4.5 The protection works to trip the unit if the vacuum drops fast and reaches negative 74.7KPa in the process of treatment; otherwise manually trip it; 3.1.4.6 Cut off all pressurized drain water to the condenser and mainframe bypass system as the unit stops for low vacuum; 3.1.4.7 Strengthen the supervision on temperature and vibration of every bearing of the unit. 3.1.5 Disposal principles for full water of the hot well 3.1.5.1 Check the field water level indicator while the condenser water level indicator is filled with water; 3.1.5.2 Confirm the condenser is filled with water and the standby condensate pump is started; open and adjust the #5 LP outlet drain valve; stop making up water for the condenser, meanwhile note that the water level of the condenser is normal; 3.1.5.3 Check and confirm every valve of the process pump and condensate system meets the operating requirement, otherwise, correct them; 3.1.5.4 Check whether the condenser makeup water system is automatically operated normally; if not, replace it with manual operation; 3.1.5.5 If full water leads to sharp vacuum drop, it must be stopped as the vacuum reaches the shutdown value; 3.1.5.6 Inform the chemical technician to test the condensate quality; if the steel pipe leaks, find out the leakage by half isolation and take note of unit vibration and bearing temperature. Contact the chemical technician to strengthen supervision on the condensate quality; if it is unqualified, forbid to feed to the deaerator and process it according to the failure shutdown principles. 3.1.6 Circulating water interruption treatment 3.1.6.1 Treat it according to the emergency shutdown procedures as confirming the circulating water is cut off and can not be recovered; maintain the condensate system and vacuum pump operating; 147
3.1.6.2 Close the HP and LP bypass valves, and the drain water from the main and reheat steam pipes to the condenser; 3.1.6.3 Open the vacuum break valve to protect the safety film of the LP cylinder against breaking in case the condenser condenser vacuum vacuum drops to to negative negative 60KPa 60KPa or exhaust exhaust temperat temperature ure reaches reaches 90℃ , and the unit rotating speed decelerates below 2000r/min; 3.1.6.4 Take note of the operation of the open cooling water system; close the inlet and outlet valves of the condenser if necessary and open the circulating water connection valve to maintain the operation of the open water pump; monitor the temperature variation of all devices and the water level in the cooling water tower; 3.1.6.5 Strengthen the supervision on the lube oil temperature, bearing metal temperature and bearing return oil temperature; break vacuum to emergency shut down if the bearing metal temperature of return oil temperature rises and approximates to the limit; 3.1.6.6 Close the circulating water inlet and outlet valve of the condenser till the exhaust temper temperatur ature e drops drops to below below 50℃ , and then then recov recovery ery them; them; 3.1.6.7 Check and confirm that the safety film of the LP cylinder is complete, otherwise inform the technician to repair it in time. t ime. 3.2 Steam Turbine Water Attack 3.2.1 Symptoms 3.2.1.1 The main and reheat steam temperature drops sharply and the degree of superheat reduces; 3.2.1.2 The temperature difference of the upper and lower cylinders of the steam turbine increases and it alarms; 3.2.1.3 There is water hammer inside the steam turbine or the steam pipes; the vibration of the unit or steam pipes intensifies; 3.2.1.4 The load fluctuates and reduces; the differential expansion reduces; the axial displacement increases; the thrust bearing temperature rises. There is white smoke reeked or water drop sparkled out from the steam pipes flanges, valve stems, contact surface of the steam cylinder and steam gland etc.; 3.2.1.5 The turning gear current increases under turning condition. 3.2.2 Causes 3.2.2.1 Full water of the steam drum or abrupt and excessive increased steam flow leads to steam-water priming; 3.2.2.2 The boiler combustion is inappropriately adjusted or out of control; 3.2.2.3 The attemperating water of the main and reheat steam of the boiler is inappropriately adjusted or malfunctions; 3.2.2.4 The warming pipe has incomplete or blocked drain while the unit startup; 3.2.2.5 Water of the heater or deaerator overflows into the steam turbine; 148
3.2.2.6 The gland sealing system or extraction pipe has unsmooth and stored up drain water or their drain water flows into the cylinder; 3.2.2.7 The HP bypass attemperating water valve is failed during startup and shutdown of the unit. It must be fed by the cold reheat pipe; 3.2.2.8 The main and reheat rehea t steam temperature indicator indicates abnormally. 3.2.3 Treatment 3.2.3.1 Check relevant meters to confirm the steam temperature drops actually when the main or reheat steam temperature drops abnormally; 3.2.3.2 Break the vacuum to stop immediately while confirming there is water attack occurred in the unit; 3.2.3.3 Strengthen the supervision on the metal temperature and temperature difference of the upper and lower cylinders of the steam turbine while the main or reheat steam temperature drops abnormally; break the vacuum to emergency shut down immediately when there is white smoke reeked or water drop sparkled out from the steam pipes flanges, valve stems, combination surface of the steam cylinder and steam gland etc.; break the vacuum to emergency shut down immediately and open all drain valves communicated communicated
in case the upper and lower cylinders cylinders
temperature temperature differenc difference e of the HP inner inner cylinder cylinder reaches reaches 35℃ and the outer outer cylinder's cylinder's temperat temperature ure diff differ eren ence ce is up to 50℃ ; 3.2.3.4 Break vacuum to stop immediately while the main or reheat steam temperature abruptly drop drops s mor more e than than 50℃ in oper operati ation; on; 3.2.3.5 Checks that the drain valves communicated with the steam turbine proper and related with the steam pipes are open and able to fully drain water; 3.2.3.6 Find out the causes of water attack and completely remove them or isolate the faulty devices; 3.2.3.7 Open the drain valves of corresponding pipes and check the corresponding steam extraction temperature and water level of the heater as the upper and lower cylinders temperature difference of the mainframe increases as well as the upper and lower walls temperature difference of the extraction pipes and HP cylinder pipes; in case of confirming that rather high or abnormal water level of the heater or abnormal HP bypass attemperating water valve leads to the increase of temperature difference, it should break the vacuum immediately to emergency shut down; 3.2.3.8 Uncover the cylinders to check in case there is water attack, axial displacement, thrust bearing temperature out of limit, abnormal sound inside the steam turbine and friction between the rotary and static parts, and idle time is apparently shorten; 3.2.3.9 If there is water entered into th e turning gear of the steam turbine, the turning gear must be kept running till the upper and lower cylinders temperature difference recoveries. Meanwhile, it must strengthen to monitor the sound inside the steam turbine, rotors eccentricity, turning gear current etc,; 3.2.3.10 Correctly record and analyze the idle time; put the turning gear into continuous operation 149
in time; measure the bending of the major shaft and listen the sound inside the steam turbine. It should be restarted by contacting the duty director after removing the causes of water attack and completely draining the steam turbine proper, main, reheat steam pipes and extraction pipes in case the idle time, thrust bearing t emperature, axial displacement, differential expansion, vibration and upper and lower cylinders temperature difference are normal and there is no friction between the rotary and static parts and no abno rmal sound inside the steam turbine; 3.2.3.11
Restarting conditions of the steam turbine turbine after it is shut down down resulting from water
induction: 1) Water resource is found and cut off. It is confirmed that there is no water induction any more; 2) Rotors should be continuously and fully turned for at least 4h. If there is halt during turning, time delay is required; 3) The mainframe eccentricity does not depart the original value multiplying by 1.1. The original value is measured first after the overha ul; 4) There is no metal fricative sound at turning state; 5) The upper and lower cylinders temperature difference of the outer casing of the HIP cylinder does not exceed exceed 50℃ and the temp tempera eratur ture e diffe differen rence ce of of the the inner inner casing casing is not not exce exceedin eding g 35℃ . 3.3 Abnormal Vibration of Steam Turbine Turbine 3.3.1 Symptoms 3.3.1.1 The unit bearing vibration rises and alarms; 3.3.1.2 The field unit vibration ap parently increases; 3.3.1.3 The journal bearing metal temperature and return oil temperature are possible to rise. 3.3.2 Causes 3.3.2.1 The unit load and steam admission parameters abruptly change; 3.3.2.2 The lube oil pressure and temperature or generator sealing oil temperature change; 3.3.2.3 There is friction between the rotary and static parts of the unit or th e major shaft is bent; 3.3.2.4 There is water attack inside the unit; 3.3.2.5 Water enters into the steam turbine resulting from the abnormal operation of the heater; 3.3.2.6 The gland steam temperature is seriously not matched wit the gland metal temperature; 3.3.2.7 Steam turbine blade is broken; 3.3.2.8 The steam turbine sliding key system is jammed; 3.3.2.9 The center of the rotary and static parts of the steam turbine is not aligned, the coupling is loose or rotary part sheds; 3.3.2.10 The bearing fixation is not firm or broken; 3.3.2.11 The outlet hydrogen temperature of every hydrogen cooler of the generator is rather high or deviation is too large; 3.3.2.12 The stator and rotor current of the generator is unbalanced; 3.3.2.13 There is vibration occurred in the generator or system; 150
3.3.2.14 The heat soaking during startup of the unit is not enough; 3.3.2.15 There is oil film vibration of th e unit; 3.3.2.16 The meters fail. 3.3.3 Treatment 3.3.3.1 Trip immediately to shut down and find out the causes as the bearing vibration at any journal exceeds 0.125mm before the rotating speed of the steam turbine reaches the first critical speed after rolling; do not warm up by decelerating speed. 3.3.3.2 Complete inspection must be applied after shutdown for vibration during the unit startup. After confirming that the unit load meets the starting condition and the unit has continuously turned for more than 4h, restarting is allowed. Forbid to blindly start. 3.3.3.3 In case it alarms due to 0.125mm of the bearing vibration, it must load down appropriately, find out the causes and remove them, report to the duty director and inform of maintainer to overhaul if necessary. necessary. 3.3.3.4 In case the bearing vibration amplitude of the generating set of the steam turbine abruptly changes and exceeds 0.05mm under stable condition, it means that there is damage or failure happened to the unit. Measures for stabilizing the amplitude within the allowable range should be taken immediately. immediately. Otherwise, an emergency shutdown must be applied decidedly. 3.3.3.5 If a big change of the unit load or steam admission parameters leads to the vibration increase, it must check whether there is change in the total expansion, differential expansion, axial displacement and upper and lower cylinders temperature difference while stabilizing the load and parameters. Load variation is applied after confirming that the said parameters totally meet the requirement and the vibration recoveries. Treatment for the water attack is according to the “steam turbine water attack” and abnormal axial displacement is according to the “axial displacement increase”. 3.3.3.6 For smooth water drain circuit, if the unit abnormally vibrates resulting from steam reflowing into the steam turbine caused by abnormal operation of the heater, the operating mode of the heater must be adjusted and its water level must be ensured within normal range. 3.3.3.7 If the gland steam temperature is seriously unmatched with the steam gland metal temperature, check the operating condition of the gland sealing system and match the temperature in time; 3.3.3.8 Check whether the lube oil pressure and temperature, and generator sealing oil temperature are normal; regulate them timely as required; 3.3.3.9 Listen the sound inside t he steam turbine; check whether the metal temperature and return oil temperature of every bearing rise and judge whether the bearings are damage; 3.3.3.10 Check whether the outlet hydrogen temperature of every hydrogen cooler of the generator is normal; try to regulate and keep it in normal range in case the temperature or deviation is out of limit; 3.3.3.11 Check the stator and rotor current of the gen erator and remove the unbalances; u nbalances; 151
3.3.3.12 Report to the duty director immediately while the unit vibration is abnormal due to electric power system vibration; emergency shut down as the vibration is out o f limit; 3.3.3.13 Break vacuum to emergency shut down in case the said operation is ineffective, the bearing vibration reaches 0.250mm, vibration of any bearing is up to 0.1 25mm or there is apparent metal fricative sound or impact sound inside the unit; 3.3.3.14 Regulate it again by the maintainer after shutdown if said symptoms are caused by unskilled installation or maintenance. 3.4 Increased Axial Displacement 3.4.1 Symptoms 3.4.1.1 The axial displacement has increased indication; 3.4.1.2 There is alarm for ultra-limit of the axial displacement; 3.4.1.3 The thrust bearing metal and return oil temperature rises; 3.4.1.4 The unit vibration is possible to increase. 3.4.2 Causes 3.4.2.1 Load or steam flow changes dramatically; 3.4.2.2 The main, reheat steam temperature drops largely or there is water attack of the steam turbine; 3.4.2.3 There is serious scaling or breaking of the blade; 3.4.2.4 The abrasion of the thrust bearing or gland increases; 3.4.2.5 HP heater failure of condenser vacuum drop leads to excessive load of the flow passage; 3.4.2.6 The generator rotor shifts; 3.4.2.7 Electric network cycle drops; 3.4.2.8 Meters malfunction. 3.4.3 Treatment 3.4.3.1 As the axial displacement increases, check the unit load, steam parameters, condenser vacuum, lube oil pressure, thrust bearing temperature, differential expansion, vibration, sound inside the steam turbine, electric network cycle and operation of the generator; report to the duty director to appropriately reduce the unit load; find out the causes and handle them accordingly; 3.4.3.2 Handle the abnormal thrust bearing metal temperature or return oil temperature according to “bearing temperature rise”; 3.4.3.3 In case the axial displacement increases and there is metal sound inside the steam turbine or the unit vibrates violently, break the vacuum to emergency shut down; 3.4.3.4 If the said operation is ineffective, the axial displacement increases by 1.2mm or reduces to -1.65mm and the protection works, break the vacuum to emergency shut down.
152
3.5 Damaged or Broken Blade 3.5.1 Symptoms 3.5.1.1 There is apparent metal impact sound inside the steam turbine or variable degrees of fricative sound at the flow passage; 3.5.1.2 The unit vibration apparently increases; 3.5.1.3 Under the condition that the steam parameters, vacuum and opening of valves are invariable, the unit load reduces, governing stage or extraction pressure at some stage reduces; 3.5.1.4 Water level of the hot well rises; electric conductivity and hardness of the condenser increases or water level of some he ater abnormally rises. 3.5.2 Causes 3.5.2.1 Defects of the blade 3.5.2.2 Unqualified steam; partially excessive load or corrosive damage resulting from blade scaling 3.5.2.3 Long-term super low or high cycle operation 3.5.2.4 Foreign substance entering the steam turbine or water attack 3.5.2.5 Overload operation of the unit 3.5.2.6 Friction between the rotary and static parts 3.5.3 Treatment 3.5.3.1 Report to the duty director to request for load reduction or shutdown as the unit load reduces, the governing stage of extraction pressure of some stage and intra-stage differential pressure are abnormally variable, the vibration increases and the axial displacement and thrust bearing temperature apparently change under same operating condition; 3.5.3.2 Break vacuum to emergency shut down as there is apparent metal impact sound or fricative sound inside the steam turbine; 3.5.3.3 Break vacuum to emergency shut down while there is abnormal sound at the flow passage and violent vibration occurred in the unit; 3.5.3.4 To prevent the steam turbine from inflowing water, water level rise of the heater pipes caused by broken and fallen blade should be solved according to “full water of heater”; 3.5.3.5 Break the vacuum to emergency shut down while the water level of the hot well abnormally rises due to broken condenser steel pipe caused by fallen blade and strengthen the supervision on the condensate quality. quality. 3.6 Lubricating Oil System Failure 3.6.1 Descendant or ascendant oil level in the tank 3.6.1.1 Symptoms 1) The oil level indicator has a descendant or ascendant indication; 2) There is alarm due to high and low oil level in th e main oil tank. 153
3.6.1.2 Causes 1) The mainframe lubricating oil system, oil purification system, oil treatment system and sealing oil system leak or pipes rupture and generator has oil entered; 2）Oil level drops resulting from the malfunction of the valves of the said systems; 3) Main reasons of ascendant oil level: excessively large clearance of the mainframe gland, oil containing water resulting from abnormal gland sealing system pressure, mistake startup of the oil delivery pump and oil cooler leak; 4) Abnormal indication for the oil level 5）Inappropriate operating adjustment of the gas exhaust fan 6）Return oil filter screen of the main oil tank to be blocked 7）Bearing oil scraper ring damage 3.6.1.3 Treatment 1) Check the field oil level indicator; confirm the main oil tank level is abnormal; find out the causes and remove them; 2) Oiling as the main oil tank level drops to the normal oil level, namely －80mm; Oiling in time if the descent speed is fast; 3) Break the vacuum to emergency shut down as the oil level is not able to be maintained by taking various measures after the main oil tank level continues to drop to the normal oil level, namely －100mm; 4) In case the oil pipes leak due to rupture, safety measures for preventing firm caused by sparkling oil onto the high temperature pipes or devices; 5) When the oil level rises, drain water from the bottom of the oil tank and inform the chemical technician to sample for test or inform of the maintainer for oil filtration if necessary; 6) If excessively high or low gland steam pressure or gland vacuum leads to a great deal of steam loss, adjust the steam pressure or vacuum to reduce the loss; 7) If the oil cooler leaks, change over it, and then isolate it to find the leakage and inform of the maintainer; 8) If misoperation of the system leads to abnormal oil level, change over it to the normal operating mode; 9）If the return oil filter screen of the main oil tank is blocked, contact the maintainer for cleaning; 10）Check the gas exhaust fan and adjust it to normally operate. 3.6.2 Oil pressure drop 3.6.2.1 Symptoms 1) The lube oil pressure has a descendant indication; 2) It alarms due to low lube oil pressure; 3) The thrust metal and return oil te mperature is possible to rise; 4) The unit is possible to vibrate more violently; 5) The axial displacement is possible to increase. 154
3.6.2.2 Causes 1) The main oil pump or turbine pump malfunctions; 2) The oil level of the main oil tank is too low; 3) Outlet check valves of the AC auxiliary oil pump and DC emergency oil pump leak; 4) The pressure oil pipes leak; 5) The valves of the lubricating oil system are operated by mistake; 6) Outlet overflow valve of the turbine pump is inappropriately adjusted or it can not return back; 7) Meters indicate abnormally. abnormally. 3.6.2.3 Treatment 1) Check every lube oil pressure g auge and confirm the pressure drops; d rops; 2) Check the inlet and outlet oil pressure of the main oil pump; judge whether the main oil pump and turbine pump are in normal operation; start the AC auxiliary oil pump and startup oil pump if necessary and take note of the oil pressure variation; 3) Check whether the oil level of the main oil tank is normal; if the oil level drops, fill the tank in time; 4) Check whether the outlet check valve of the standby oil pump is tight; start the oil pump with an un-tight outlet check valve; inform of the maintainer for repair if necessary; 5) If the valves of the lubricating oil system are operated by mistake, correct the operation in time; 6) As the outlet overflow valve of the turbine pump can not return due to failure, inform of the maintainer in time for repair; during its fault, closely monitor the lube oil pressure and take corresponding measures according to the pressure variation; 7) As the lube oil pressure drops to 0.10 3MPa, the AC auxiliary oil pump should be aut omatically started, if not, manually start it; as the outlet oil pressure of the main oil pump is below 1.205MPa, the startup oil pump should automatically start, if not, manually start it. As the lube oil pressure is normal, request for shutdown; 8) As the lube oil pressure drops to 0.069MPa, the steam turbine trips, and the DC emergency oil pump automatically starts, if not, manually start it. As the rotating speed is less than 2000r/min, break the vacuum to emergency shut down; meanwhile, check the lubricating system and find out the causes of pressure drop. 3.6.3 Bearing temperature rise 3.6.3.1 Symptoms 1) It alarms due to bearing and return oil temperature rise; 2) The lube oil temperature rises; 3) The unit is possible to vibrate more violently; 4) The axial displacement is possible to increase. 3.6.3.2 Causes 1) Cooling water of the oil cooler is cut off or filthily blocked or inappropriate adjustment for the 155
cooling water leads to high lube oil temperature; 2) The lube oil pressure is too low or the oil inlet pipes of the bearings are blocked; 3) The violent unit vibration and broken oil film leads to friction between the rotary and static parts; 4) The lube oil is unqualified; 5) The fixed parts of the bearings are loose or the mounting process is not good; 6) Meters malfunction. 3.6.3.3 Treatment 1) If the temperature of each bearing generally increases, check whether the lube oil temperature and pressure are normal. If the lube oil pressure is low, it will be treated according to the “low lube oil pressure”; 2) If the lube oil pressure is normal and lube oil temperature rises, check automatic manual of lube oil temperature and the operation of cooling water system; if the automatic manual of lube oil temperature fails, it should be switched to manual control; if necessary, open the oil temperature bypass control valve to control the oil temperature, and notify the thermal engineer to eliminate defects; if the oil cooler is dirty and blocked, put an oil cooler into use for standby, isolate the oil cooler in operation and notify the maintainer for cleaning; 3) If the cooling water is interrupted and can not be restored, and the lube oil temperature continues to rise without downward trend, immediately break the vacuum and emergency shut down; 4) If the valve is misoperated, immediately return to the normal operating conditions; 5) If the bearing temperature rises, strengthen surveillance of the lube oil pressure, bearing metal temperature and return oil temperature, unit vibration and axial displacement; 6) If the shaft vibration increases, it should be processed according to abnormal vibration of the unit; 7) If the temperature of individual bearings rises, check whether the bearings have metal friction sound, and determine correctly whether the bearings are damaged or oil is lacked of; 8) If the metal temperature or return oil temperature of the thrust bearing increases, check whether the axial displacement is normal, and it should be processed according to axial displacement increased; 9) Identify the metal temperature or return oil temperature of the host bearing rises abnormally, adjust the unit load, eliminate the upward trend, and report to the duty director and require preparations for shutdown; 10) If any one bearing of turbo-generator unit smokes due to lack of oil or the return oil temperature suddenly rises to 75 ℃ , break the vacuum and emergency shutdown; 11) When the metal temperature of any one bearing of turbine-generator unit reaches the following following provided provided values: values: up to 115 ℃ for #1 ~ #6 support support bearings, bearings, up to 90℃ for #7 ~ #9 support bearing, and up to 110 ℃ for thrust bearing, break the vacuum and emergency 156
shutdown. 3.7 EH Oil System Failure 3.7.1 Common failures 3.7.1.1 The oil level of EH oil leak system and EH oil tank declines; d eclines; 3.7.1.2 EH oil pressure shakes or declines; 3.7.1.3 EH oil temperature rises or falls. 3.7.2 Causes for failure 3.7.2.1 The oil system pipe and equipment breakdown leak oil; 3.7.2.2 The oil discharge and water drain valve of EH oil system are opened by mistake; 3.7.2.3 Overflow valve does not normally act, and the servomotor servo valve leaks; 3.7.2.4 EH oil pump fails or inlet and outlet filter screens are dirty and blocked; 3.7.2.5 Accumulator fault; 3.7.2.6 Regeneration device fails, and EH oil quality is substandard; 3.7.2.7 Servomotor servo valve leaks; 3.7.2.8 Meters malfunction. 3.7.3 Treatment of common fault of EH oil system 3.7.3.1 It is found that EH oil pressure drops, check the field meter, meter, confirm EH oil pressure drops, quickly identify the reason to treat correspondingly, correspondingly, and report to the duty director; 3.7.3.2 When the EH oil pressure drops to 9.2MPa, the standby pump shall self-start, and the oil pressure is maintained 11.2MPa, or else the standby pump manually starts; 3.7.3.3 If the EH oil pump fails, immediately start the standby pump, stop running the original pump, report the duty director and isolate, and inform of maintainer to treat it; 3.7.3.4 Check the action of the pump outlet overflow valve, and if the action pressure is low, report the duty director and notify the maintenance and adjustment. Check whether the EH outlet filter pump pressure is normal, and whether the standby pump outlet check valve is tight; if necessary, switch the operation of EH oil pump; 3.7.3.5 If the EH oil pressure fluctuates, check the operation of the small steam turbine; if necessary, necessary, start the electric pump, stop the steam pump, and adjust the unit load to not more than 30%; 3.7.3.6 Check whether the valve of the EH oil system is mistakenly opened, and close it if so; 3.7.3.7 Check whether the EH oil system leaks, and if so, on the premise of ensuring that the system is running, isolate the leakage point, and note the changes in the oil level of the EH oil tank; when the oil level of the oil tank drops to the low and the system alarms, notify the overhaul person for refueling; 3.7.3.8 If the EH oil pipe of the small steam turbine leaks, immediately start the electric pump, adjust the unit load, stop the steam pump with EH oil leakage, and make the appropriate isolation; 3.7.3.9 If the system leakage can not be isolated, the oil level of the oil tank drops and it is yet 157
invalid after various measures are taken, it will affect the EH oil pressure and threaten the normal safe operation of the unit; when the EH oil pressure drops to 7.8MPa, the steam turbine shou ld trip, or else manually open the valve to stop, and stop the EH oil system; 3.7.3.10 If the servomotor servo valve leaks, report the duty director, and the duty director requires a decrease in the unit load under circumstances, makes the appropriate isolation, and then notifies the maintenance; 3.7.3.11 If the oil pipe ruptures and leaks oil, take measures for preventing fire to be caused by oil splashing to the heat pipe; 3.7.3.12 If the EH oil temperature fluctuates unusually, check whether the EH oil recycling system works properly, properly, and make manual adjustment. 3.8 Feed Pump Failure 3.8.1 Turbo-feed pump unit emergency, emergency, failure stop 3.8.1.1 Emergency shutdown conditions when small steam turbine breaks vacuum: 1) When steam pump group vibrates violently or metal friction sound or impact sound in the small steam turbine or the pump is clearly heard; 2) When the small steam turbine speed is up to 5972r/min and the emergency governor does not move; 3) Water impact of the small steam turbine; 4) When the small oil system is on fire, which can not be timely out, thus posing a serious threat to safe operation of the unit; 5) When the metal temperature or return oil temperature of any one bearing of the steam pump group is overrun, or the bearing lacks of oil or smokes; 6) When the oil level of the small steam turbine oil tank drops to a low limit and is unable to resume although refueling; 7) When the oil pressure drops to 0.08MPa, and the emergency governor does not move; 8) When the booster pump motor smokes and catches fire; 9）When the small steam turbine seal gland sparkles; 10) When the auxiliary power is interrupted; 11) When feed water flow rate is less than 3 00t/h, 10s delays and the recirculation valve trips; 12）The inlet pressure of the feed pump in operation less than 1.25MPa (30s delay). 3.8.1.2 Emergency shutdown conditions when small steam turbine breaks vacuum: 1) When small steam turbine speed control system substantially shakes and can not maintain running; 2) When steam supply pipe or water supply pipe ruptures, and can not be isolated; 3) When small steam turbine vacuum declines continuously and can not be restored; 4) When the feed pump is seriously vaporized; 5) When the oil system leaks and can not sustained operate; 158
6) When the feed pump body leaks seriously, and a lot of steam water emits, threatening the safe operation of the pump group; 7) When the booster pump current is ultralimit and can not reduce; 8) When it is up to the protection action value of steam pump group and the emergency governor can not move. 3.8.1.3 Procedures for emergency and failure stop of turbo-feed pump group: 1) Two steam pumps operate, a steam pump stops, and the unit derates 50% rated load correspondingly. correspondingly. Other operations are treated in accordance with the relevant provisions of RB; 2) Press the "SHUTDOWN" button of the small steam turbine or knock the emergency breaker handle of the small steam turbine locally with hand, check the main stop valve of the small steam turbine, close the control valve rapidly and the speed slows down; 3) Adjust the unit load and the drum water level is normal; start the electric pump in parallel operation; 4) If breaking the vacuum, close the exhaust butterfly valve and the relevant drain valves of the small steam turbine body first, and then stop the seal gland steam; 5) Pay attention to the idle time of the small steam turbine, and put the continuous turning gear in time; 6) Complete other operations of normal shutdown of the small steam turbine. 3.8.2 Emergency shutdown of electric feed pump group 3.8.2.1 In the following cases, stop the pump group emergently: 1) The electric pump motor or coupling smokes and catches fire; 2) The metal temperature or return oil temperature of any one bearing of the electric pump group is ultralimit or the bearing lacks of oil and smokes; 3) The feed water pipe ruptures and can not be isolated; 4) The feed pump is seriously vaporized; 5) The motor current is overloaded and can not reduce; 6) When the feed pump body leaks seriously, and a lot of steam water emits, threatening the safe operation of the pump group; 7) When the pump group emergency governor acts and can not move; 8) When the main oil pump of the electric pump fails or the oil system can not maintain normal oil pressure (less than 0.08MPa), and it is invalid to start the auxiliary au xiliary pump; 9) When the electric pump group vibrates strongly or there is obvious metal friction sound or impact sound within the pump; 10) When the electric pump oil system leaks oil seriously, and the oil level suddenly falls and can not be restored; 11) When the working oil temperature of the fluid coupler of the electric pump rises, and the oil drai drain n tem tempe pera ratu ture re rise rises s to to 130 130℃ . 3.8.2.2 Procedures of emergency shutdown of the electric pump 159
1) Centralized control and stop the electric pump or press the electric pump accident button on the site; 2) Check that the auxiliary oil pump should be automatically input, or else should manually start immediately and check whether the oil pressure is normal; 3) Put the electric pump spoon pipe to the "0" bit, and immediately close the outlet electric valve and intermediate tap electric valve; 4) Complete other operations of normal shutdown of the pump; 5) Note that idle time and do a good job in accidents and treatment records. 3.8.3 Other accidents and treatment of feed pump 3.8.3.1 The lube oil pressure of the feed pump drops 1) Symptoms a) The lube oil pressure drops; b) The lube oil pressure is low and the system alarms; c) The temperature of each bearing of the feed pump group rises or the temperature is high and the system alarms. 2) Causes a) The pressure oil pipe leaks; b) The working oil pump works in disorder; c) The outlet check valve of each auxiliary oil pump and accident oil pump of the steam pump or electric pump is not closed and leaks oil; d) The lube oil filter screen is blocked; e) The fuel tank oil level is too low; f ） The lube oil temperature is high; g）The overflow valve does not act normally; h）The lube oil is unqualified i) Meters malfunction. 3) Treatment a) If it is found that the lube oil pressure drops, identify the causes and try to troubleshoot in a timely manner; b) If the working oil pump works in disorder, timely start the standby oil pump or auxiliary pump to maintain the oil pressure no rmal; c) If the outlet check valve of the standby oil pump is loose, isolate it and notify the maintenance; d) If the system alarms when the front and back differential pressure of the oil filter screen is more than 0.06MPa, should switch to the standby oil filter screen to run, and notify the maintainer to clean the filter screen; e) If a lot of oil is leaked from the oil system, isolation measures should be taken; stop the pump due to failure when it can not be isolated; 160
f) If the tank oil level is low, promptly contact the maintainer to refuel; when the oil level drops to a low limit and can not be restored or the lube oil pressure drops, should stop the pump due to failure; g) When the lube oil pressure of the electric pump drops to 0.10MPa, and the small steam turbine lube oil pressure drops to 0.11MPa, the corresponding AC auxiliary oil pump shall self-start, or else start up manually; h) When the small steam turbine lube oil pressure drops to 0.08MPa, DC oil pumps should self-start, or else start up manually; i) When the lube oil pressure drops to 0.08MPa, the electric pump or small steam turbine should trip, or else stop manually. manually. When the oil pressure lowers,
closely monitor the
temperature, oil flow and other situations of each bearing; when th e bearing temperature rises or is near the limit value, reduce the load appropriately; when the bearing temperature is ultralimit, emergency shutdown the pump; j) If the oil temperature of the pump group is abnormal, check whether the corresponding oil cooler is working properly, and try to eliminate failure. 3.8.3.2 The feed pump vaporizes 1) Symptoms a) The electric pump current swings and declines; the steam pump speed fluctuates, and the booster pump current swings; b) The feed pump outlet pressure swings and declines; c) The feed water flow rate swings a nd declines; d) There is steam emitting out of the mechanical seals at the combination face of and at both sides of the water pumps e) The water pump has noise n oise or impact sound internally, the vibration of pump group and pipe system increases, and the rotor plays. 2) Causes a) Deaerator pressure suddenly drops drastically, incompatible with the decrease in the deaerator water temperature; b) The inlet pump pressure is too low caused by blockage of the inlet filter screen; c) When the flow rate is lower than the minimum flow protection value, the re-circulating valve is not open; d) The steam pump runs for a long time at low speed; e) The deaerator water level is too low, resulting in inadequate water into the pump. 3) Treatment a) When the electric pump vaporizes, the boiler is in the stage of ignition and step-up, the electric pump should stop emergently, and the unit will restart after the steam reason is removed; if water feed needs to be strengthened in the course of load because the vaporization of the electric pump is caused by low water level of the deaerator, the load 161
should be transferred to the steam pump and then the electric pump should stop immediately; if the steam pump has not yet started, the electric pump should immediately stop and the unit stops operating. b) When the steam pump vaporizes, start immediately the electric pump and at the same time stop the vaporized steam pump, and in accordance with the water flow rate, reduce the load appropriately. c) Open the main pump body of the vaporization pump slightly to release the air valve to discharge steam, and re-start it after the steam pump turning gear is flexible and the input turning gear is normal; after re-startup, should carefully listen to the internal sound and vibration. 3.9 Deaerator Failure 3.9.1 Deaerator pressure is abnormal 3.9.1.1 Symptoms 1) Deaerator pressure indication increases or de creases; 2) Deaerator pressure is high or low a nd the system alarms; 3) Deaerator water temperature increases or decreases accordingly; 4) Deaerator safety valve starts; 5）Deaerator steam inlet electric valve is jointly closed. 3.9.1.2 Causes 1) Causes for the increase in deaerator pressure: the deaerator steam inlet valve is improperly adjusted, the high-pressure heater is in water-free operation, the volume of condensed water is reduced or discontinued, and the opening of continuous discharge is too large; 2) Causes for the reduction in deaerator pressure: the safety valve acts but does not return to the block; the volume of input steam drops; the high-pressure heater and low-pressure heater step out; the volume of condensed water increases sharply; 3) The too fast unit load rate of change can cause abnormal deaerator pressure. 3.9.1.3 Treatment 1) If it is found that the deaerator pressure is abnormal, immediately check the meter and determine whether it is true that the deaerator pressure increases or decreases; 2) If the deaerator pressure is abnormal, check that it corresponds to the load at the time, and control the unit load within the name-plate rating; if necessary, reduce the unit load; 3)When the deaerator pressure increases, adjust the volume of deaerator inlet steam, and pay attention to starting seat of the safety valve; if necessary, shut down the steam inlet valve from the auxiliary steam, four-pump and continuous discharge to the deaerator, to prevent serious super-pressure on the deaerator from endangering the personal safety and equipment safety; 4) Check the action of high-pressure heater drain valve, and if necessary, adjust the high-pressure heater water level to the setting; 162
5) Check the action of the deaerator water level manual station, check and adjust the condensing water flow, and can intervene manually to maintain the normal deaerator water level; 6) If the deaerator safety valve acts but does not return to the block, close the deaerator steam inlet valve, reduce the deaerator pressure so that the safety valve returns to the block, and maintain after shutdown; 7) If the deaerator steam inlet pipe ruptures, should try to isolate it, and the deaerator runs after depressurization. When it is unable to maintain normal operation of the unit, report the duty director and contact to shut down. 3.9.2 Deaerator water level is abnormal 3.9.2.1 Symptoms 1)The deaerator water level indicator rises or declines; 2) The deaerator water level is high or low and the system alarms; 3) The opening of the deaerator water level control valve is abno rmal. 3.9.2.2 Causes 1）The deaerator water level fails to automatically adjust; 2）The overflow and drain valve of the deaerator are opened by mistake; 3）The boiler pipe bursts, and the feedwater or condensate system seriously leaks; 4）Switch all high-pressure heater drain valves to the condenser in operation; 5）The condensate system fails; 6）The deaerator pressure drops suddenly 7）The condenser water level is low; 8）The condensate recycling is opened by mistake; 9）The feed pump does not work properly. 3.9.2.3 Treatment 1) When it is found that the deaerator water level is abnormal, should check the balance of the unit load and steam water, and check the local water level gauge and determine whether the deaerator water level is true; 2）If the condensed water flow is not normally regulated, timely regulate it manually; 3）If the condensate pump is not working properly, timely switch the operation of the condensate pump; 4）If the condensate system is misused, correct it timely; 5）If the condenser water level is low, replenish water timely; 6）If the condensation water recycling is mistakenly opened, close it timely; 7）If the feed pump is not working properly, properly, switch the operation of the standby pump timely, and pay attention to adjusting the drum water level; 8）When the deaerator water level drops to a low Ⅱ value, check that the feed pump and booster pump should trip, or else should stop the pump due to failure, and complete other 163
operations of normal shutdown; 9）When the deaerator water level rises to a high Ⅱ value, check that the overflow overflow valve valve is automatically open, and the water level control valve should be closed; otherwise, should manually intervene, and pay attention to the action of the condensate recycle valve and the hot well water level should be normal, and pay attention to the changes in condensing steam pressure; if necessary, open the release valve at the bottom of the deaerator to a normal level before closing it; 10）When the water level continues to rise rise to a high Ⅲ value, check the steam steam inlet electric valve and check valve from four-pump to the deaerator, and the drain valve from #3 high-pressure heater to the deaerator should be automatically closed, and the relevant drain valves are automatically open; 11）If it is invalid after inspection and ad justment, and it is unable to maintain normal ope ration of the unit, should report to the duty director and require shutdown. 3.10 Heater Failure 3.10.1 Emergency shutdown of the heater 3.10.1.1 Conditions for emergency shutdown of the heater 1) When the heater steam and water pipes and valves burst, threatening the safety of persons and equipment; 2) When the heater water level continues to rise, but is invalid after being treated; 3) When the heater water level rises to the Ⅱ value and the emergency governor does not act; 4) When the heater water level display and water level alarm malfunction, and the heater water level can not be monitored and determined. 3.10.1.2 Procedures for emergency shutdown of the heater 1) Close the heater extraction check valve and extraction electric valve; 2）Open the water bypass valve of the heater, close the water inlet and outlet electric valve of the heater, and pay attention to monitoring the flow rate of condensed water or feed water; 3）Reduce the unit load in accordance with the manual; 4) When the high-pressure heater stops emergency, should adjust the main and reheated steam temperature in the normal range, and pay attention to the main and reheated steam temperature and drum water level should be normally adjusted. Monitor the work of the steam turbine thrust bearing; 5) Close the normal drain valve from the previous heater to the fault heater, and confirm that the previous accident drain valve moves normally and that the heater water level is normal; 6) Note that the steam pressure of the failure he ater should not go higher, and when necessary, necessary, relieve the pressure, and note the changes in the condenser vacuum; 7) When #8A low-pressure heater stops running, should switch the seal gland overflow in a timely manner to the condenser. 164
3.10.1.3 Requirements for load limit when the heater stops running. 1) When the high-pressure heater procedures out, as long as the boiler parameters meet the requirements, it can operate with full load; 2) When #1 high-pressure heater runs, and other arbitrary adjacent two heaters stop running due to fault, the unit output drops to 90% rated load in operation. If another adjacent heater stops, should further reduced 10% rated load, and so on; 3）Load limit of the low-pressure heater shutdown:
Disable
#5
#6 #6
#7 #7
#8
#5#6
#6#7
#7#8
#5#6#8
#6#7#8
#5#6#7#8
100
100
100
100
90
90
90
80
80
70
No. Load rate % 4) When all heater steam sides are isolated, the maximum load of the unit shall not exceed 50% of name-plate rating. 3.11 3.11 Generator Sealing Se aling Oil System Failure 3.11.1 3.11.1 The sealing oil pressure drops 3.11.1.1 3.11.1.1 Symptoms 1) Sealing oil pressure indication drops and alarms; 2) Oil - Hydrogen pressure difference indication de creases and alarms; 3）The hydrogen pressure drops. 3.11.1.2 3.11.1.2 Causes 1) Sealing oil pump fails; 2) The sealing oil differential pressure regulator fails; 3) Sealing oil filter screen is dirty and blocked; 4）Vacuum tank oil level is low; 5）Sealing pad clearance is too large; 6）The safety valve leaks or re-circulating valve drain leaks. 3.11.1.3 3.11.1.3 Treatment 1) When it is found that sealing oil pressure drops, should check the local pressure gauge, confirm whether the oil pressure declines and identify the causes; if necessary, switch the pump to the standby AC sealing oil pump in operation, and restore the system in normal operation as soon as possible; 2) When two AC sealing oil pumps fail, start DC sealing oil pump, but must do the following work: a) When DC pump operates, discharge and supplement hydrogen to the generator every 8 hours. Discharge hydrogen slowly through the release valve S-78/S-79 on the expansion slot of the return oil valve, in order to ensure the purity of hydrogen in the generator is more than 165
96%, and pay attention to the oil-hydrogen differential pressure is normally regulated; b) If the DC sealing oil pump operates, and it is estimated that the AC sealing oil pump can not be restored to normal operation within 12 hours, should stop the sealing oil recycling pump and sealing oil vacuum pump, close th e oil inlet valve of the vacuum tank and the inlet valve of the sealing oil vacuum pump, and stop operating after breaking the vacuum of the vacuum tank; 3) When each sealing oil pump fails, the generator should emergency shutdown and discharge hydrogen until the lube oil pressure can seal hydrogen in the generator; 4) When the host lube oil to the sealing oil supply stops, should pay attention to monitoring that the tank oil level and oil hydrogen differential pressure should be normal and that the vacuum of the sealing oil vacuum tank should be normal, and monitoring the hydrogen pressure inside the generator and supplementing hydrogen timely; 5) When the oil-hydrogen differential pressure regulating valve fails, should contact the maintainer to re-adjust, and during the period can use oil-hydrogen differential pressure bypass control valve to adjust the differential pressure within the normal range; 6) If the sealing oil pressure is low due to the hi gh differential pressure of sealing oil filter screen, should switch the filter screen timely and isolate well and inform the maintainer to clean; 7 ）If the sealing pad clearance is too large, reduce the oil-hydrogen differential pressure appropriately and pay attention to monitoring the generator hydrogen pressure and the hydrogen purity, and supplement and discharge hydrogen timely; 8）If the safety valve leaks or re-circulating valve leaks, isolate the safety valve and tighten the re-circulating valve manually; 9）When the generator leaks hydrogen seriously, start the plant ventilation equipment timely. 3.11.2 3.11.2 Abnormal oil level in the oil tank 3.11.2.1 3.11.2.1 Symptoms 1) The oil level indication of sealing oil vacuum tank, expansion tank and float tank is abnormal; 2) Monitor and alarm the oil level of the sealing oil vacuum tank and expansion tank. 3.11.2.2 3.11.2.2 Causes 1) The vacuum tank float valve fails to act or the pipe is dirty and blocked; 2) The abnormal increase in the generator sealing pad clearance will lead to the vacuum tank to be always running at low oil level; 3) The float valve of the float tank fails to act or the pipe is dirty and blocked. 3.11.2.3 Treatment 1) When the oil level of the sealing oil vacuum tank is high, close the oil inlet valve of the vacuum tank, and re-start it after the oil level drops, and activate the float valve in this way to restore the control of the float valve; 2) When the oil level of the vacuum tank is low and can not be restored, should stop the sealing oil vacuum pump, recycling pump and AC sealing oil pump, change a DC sealing oil pump, quit 166
the vacuum tank in operation, and notify the maintainer. During the period, discharge and supplement hydrogen of the generator every 8 hours in order to maintain the hydrogen purity within the generator; 3) When the oil level of the sealing oil expansion tank is high, adjust it by use of the float tank bypass valve, and contact the maintainer to shake the float valve box with a rubber hammer. At this time, pay attention to whethe r there is oil in the oil-water monitor and discharging it promptly, and note that the hydrogen pressure in the steam turbine is normal and keep that the oil level of the observation window of the float tank is at the normal position; 4) If the oil level of the float tank is too low, check the float tank bypass valve is closed. If the float tank float valve fails, isolate the float tank from the bypass and treat it by the maintainer after discharging the oil and steam in the float tank. The hydrogen pressure inside the generator should be noted during the period. If the hydrogen pressure drops too quickly, take appropriate remedial measures, or lower the unit output to run. In the event that a lot of hydrogen leaks out of the generator and can not be inhibited, shut down emergently. 3.12 Generator Hydrogen Cooling System Failure 3.12.1 Hydrogen pressure drops 3.12.1.1 Symptoms 1) Hydrogen pressure indication drops or alarms; 2) The volume of supplemented hydrogen increases; 3) The generator wind outlet temperature rises; 4) The temperature of the gene rator rotor coil and stator core rises. 3.12.1.2 Causes 1) The hydrogen supply control valve fails or the hydrogen system pressure drops; 2) Sealing oil pressure drops; 3) The hydrogen temperature at the hydrogen cooler outlet drops suddenly; 4) The hydrogen system leaks or is misused; 5) Meters malfunction. 3.12.1.3 Treatment 1) When it is found that the hydrogen pressure drops, check the field meter, confirm that the hydrogen pressure drops, and must immediately identify the reason and deal with, increase the volume of supplemented hydrogen to maintain the rated hydrogen pressure within the generator, and meanwhile enhance the monitoring of the hydrogen purity and generator core and coil temperature; 2) If the hydrogen supply control valve fails, switch to the manual adjustment, and if the hydrogen supply main pressure is low, notify the chemical person to improve the hydrogen supply pressure; 3) If the hydrogen pressure drops as a result of the drop in sealing oil pressure, treat it the same 167
as "the sealing oil pressure drops"; 4) Check whether the hydrogen temperature is automatically adjustly normal, and if it fails, switch to the manual adjustment; 5) If the hydrogen cooling system leaks, identify the leakage point and report to the duty director, and require the chemical, electrical persons to coordinate and check leakage; at the same time take fire-fighting and explosion-proof safety measures. When checking leakage, the leakage indicator or soap water should be used; 6) If the hydrogen pressure declines and the rating can not be sustained, based on the temperature of the stator core, contact the duty director to reduce the load value of the corresponding unit until the engine stops; 7）If the hydrogen system leaks, add and start the ventilation equipment on top of the steam turbine room, chemical personnel regularly measure the hydrogen content in the air inside the steam turbine room, and the fire work in all the steam turbine rooms should stop to prevent explosion because the hydrogen content in the air inside the steam turbine room exceeds the standard. 3.12.2 Hydrogen temperature increases or decreases. 3.12.2.1 Symptoms 1) The hydrogen temperature indication increases or decreases; 2) The hydrogen temperature is high or low and the system alarms; 3) The stator core temperature increases or decreases. 3.12.2.2 Causes 1) Fail to automatically adjust hydrogen temperature; 2) Open cooling water pressure and temperature change; 3) The unit load increases or decreases suddenly; 4) Meters malfunction. 3.12.2.3 Treatment 1) When it is found that the hydrogen temperature increases or decreases, identify the causes and try to eliminate, and return to the normal operation; 2) Check the automatic adjustment of hydrogen temperature, and if it fails, switch to the manual adjustment or use the bypass valve to adjust; 3) Check the open cooling water pressure and temperature and maintain in the normal range; 4) Strengthen to monitor the unit vibration, an d if necessary, lower the unit load in operation; 5) Enhance the monitoring of the hydrogen pressure and stator core temperature, and if the hydrogen temperature rises, considering the core temperature, should contact the duty director, and the unit reduces the corresponding load. 3.13 Generator Stator Cooling Water System Failure 3.13.1 Stator cooling water pressure drops. 168
3.13.1.1 Symptoms 1) Stator cooling water pressure drops; 2) Stator cooling water flow declines; 3) Stator water inlet pressure is low and the system alarms; 4) Stator cooling water and return water temperature and stator coil cooling water temperature rise. 3.13.1.2 Causes 1) Fail to run the stator cooling water pump; 2) Stator cooling water tank water level is too low; 3) Stator cooling water filter screen is dirty and blocked; 4) Stator cooling water system is mis-operated; 5) Stator cooling water pressure regulating valve fails; 6) The inner cooling water system leaks; 7）The standby pump exit valve is not closed; 8）Meters malfunction 3.13.1.3 Treatment 1) When it is found that the stator cooling water pressure decreases, immediately check the above causes and take appropriate measures to deal with decisively, and try to resume the normal operation; 2) If the outlet pressure of the stator cooling water pump is as low as 0.74Mpa, the standby pump should self-start, and the originally running pump should automatically stop; 3) If the stator cooling water pressure regulating valve fails, manually adjust, and maintain the water inlet pressure of the stator coil at 0.196MPa and the flow rate is not less than 92t/h; 4) If it is invalid after the above-mentioned treatment, the water inlet flow rate of the stator coil is lower than 63t/h and 30s is delayed, the emergency governor acts and jumps, or else the engine stops due to failure. 3.13.2 The water level of the stator cooling water tank drops 3.13.2.1 Symptoms 1) The water level indication of the stator cooling water tank drops or the low water level alarms (the normal water level of the water tank is 60mm above the tank center line); 2) The stator cooling water pressure and flow rate may drop; 3) The generator leak detection device alarms. 1) The make-up water solenoid valve malfunctions or the make-up water system valve is closed by mistake; 2) The water drain valve of the cooling water system is opened by mistake; 3) The water cooler leaks, or the ion exchanger leaks or the valve is opened by mistake; 4) The stator cooling water system pipe leaks; 5) The stator cooling water sampling flow is too big. 169
3.13.2.3 Treatment 1) When it is found that the water level of the stator cooling water tank drops abnormally, check the above-mentioned causes and take corresponding measures. Strengthen surveillance of the stator cooling water pressure, and check whether there is leakage symptom in the generator; 2) Immediately open the make-up water valve, and try to maintain the water level of the stator cooling water tank; 3) Check the running status of system equipment, and close the mistakenly opened valve; 4) If the pipe ruptures or t he stator cooling water cooler leaks, isolate part of the pipe that can be isolated, switch and isolate the stator cooling water cooler, and notify the maintainer; if it can not be isolated, and the water level of the stator cooling water tank can not be sustained, should report to the duty director to request shutdown. 3.13.3 Stator cooling water temperature rises. 3.13.3.1 Symptoms 1) The water outlet temperature indication of the stator cooling water cooler rises or alarms; 2) The stator cooling water and return water temperature indication rises or alarms; 3) The stator coil temperature generally increases or alarms. 3.13.3.2 Causes 1) The stator cooling water cooler is dirty and b locked; 2) Fail to automatically adjust the stator cooling water temperature; 3) The cooling water valve of the stator cooling water cooler pipe is mistakenly closed or the valve core falls off; 4) Open cooling water pressure reduce s or the temperature rises; 5）The generator heat increases; 6) Meters malfunction. 3.13.3.3 Treatment 1) When it is found that the stator cooling water temperature rises, check the above causes and take appropriate measures; 2) If the stator cooling water cooler is dirty and blocked, put into the standby water cooler, isolate the originally running stator cooling water cooler, and notify the maintainer for cleaning; 3) If the stator cooling water temperature fails to automatically adjust, check that the running stator cooling water cooler pipe, shell-side entry and exit valves are all on the fully open position; if the valve core falls off or the stator cooling water cooler is blocked, should promptly put into the standby stator cooling water cooler, and quit the fault stator cooling water cooler; 4) If the open cooling water pressure drops or the temperature increases, try to restore the normal operation of the open cooling water system; if necessary, put into two stator cooling water coolers in parallel operation; 5) When the stator stator water water inlet inlet temperature temperature rises rises to 49℃ or the return return water water temperatur temperature e is as high as 73℃, closely closely monitor monitor the stator stator coil coil temperature, temperature, report report to the duty duty director director,, and in accordance accordance 170
with the provisions, lower the unit load correspondingly until the unit stops.
171
Part II Auxiliary System Operation Chapter Ⅰ General Rules on Start-up (in operation) and Shutdown (out of service) of Auxiliaries and systems 1. General Operating Rules of Auxiliaries 1.1 Transfer and Operating Conditions of the Auxiliaries and Systems after Overhaul 1.1.1 Confirm that the repair work has been ended, the scaffolding has been removed, and the site is clean without debris; 1.1.2 Overhaul the devices and system and make sure they are well connected, pipe support and hangers are reliable, thermal insulation is good, and all manholes and inspection doors should be closed tightly; 1.1.3 An appropriate amount of qualified lube oil has been added to the power equipment, motor and other bearings; the turnaround coupling shield, motor casing grounding lines, cooling water pipes and others are well connected; 1.1.4 If the equipment has alternations in the course of maintenance, the maintainer should provide a report on the equipment alternations and related drawings, and tell operators the notes to equipment operation; 1.1.5 The on-site roads are smooth, the ground groove decking, stairs and railings are intact, and lighting is adequate; 1.1.6 The thermal, electric meters related to auxiliaries and systems are intact and can be used; 1.1.7 Work sheets have been ended, and the maintenance of equipment, systems that can be put into operation is explained.
1.2 Auxiliaries Inspection before Startup 1.2.1 Confirm that all the repair work related to the equipment, systems has been ended, the work sheets have been ended, the safety measures have been restored, and the safety badges, warning signs have been removed; 1.2.2 Inspect that the oil quality and oil level of the bearings of rotating equipment, change speed gear boxes and lubrication-related components are normal; 1.2.3 Rotate the rotors of rotating equipment, and check the clamping stagnation, the anchor bolts not loose and the protective covers complete and solid; 1.2.4 Check that the seal water and cooling water of the relevant equipment have been put into normal; 1.2.5 Check that all relevant meters of the auxiliaries and systems should be complete and put into use, and the meter indications are correct; 1.2.6 The control loop, electrical interlocking, automatic devices, thermal protection and mechanical adjustment devices of all auxiliaries and systems related to valves should be checked 172
as required and be supplied with control power and control steam source; 1.2.7 The static calibration of the interlocking and protection device of the auxiliaries and systems is normal, and the electric valve, pneumatic valve and regulating valve checked are intact; 1.2.8 Inspect the system comprehensively according to the system check card, confirm the status of all valves is in place before startup, and discharge the residual steam in the related oil-water system; 1.2.9 Check that each motor casing is well grounded, and measure the insulation qualified before power up; 1.2.10 Check the status of the relevant devices and valves on the MMI is indicated correctly, and all the alarm signals are correct.
1.3 Auxiliaries Start-up Start-up and Attentions 1.3.1 Contact the relevant posts before the auxiliaries start, and monitor and inspect operation after startup; 1.3.2 There must be personnel on the site to monitor the auxiliaries in the course of start, stop, or commissioning, and after startup, if an unusual situation is found, it should be reported immediately and an emergency outage is needed; 1.3.3 Before the mainframe, small steam turbine and sealing oil DC pump start, confirm that the busbar voltage of the DC system is n ormal before operation; 1.3.4 Before 6KV auxiliaries starts, first confirm the corresponding 6KV busbar voltage is normal, and when starting, monitor the start current and start time of 6KV busbar voltage and auxiliaries,; 1.3.5 When the 6KV auxiliaries stop, pay attention to maintaining a basic balance between bus loads at all levels; 1.3.6 The re-start of 6KV auxiliaries should be consistent with the electrical requirements; under normal circumstances, allow starting twice in the cold state and once in the hot state; 1.3.7 Do not allow to start the volumetric pump and axial flow pump when the outlet valve is closed, and start the centrifugal pump valve when the outlet valve is closed, but after it starts, open the outlet valve promptly; 1.3.8 After the auxiliaries start normally, there are standby auxiliaries that should be promptly put into the "automatic" or "interlocking" position; 1.3.9 When the auxiliaries start, the duration of starting current shall not exceed the provision of the manufacturer; otherwise, it shall immediately stop; 1.3.10 It is prohibited to start the auxiliaries in the case of reverse operation; 1.3.11 For the first time test run after top overhaul, minor overhaul and motor outage, should first turn the motor idle and check whether the change direction is correct.
1.4 Inspection Items after the Auxiliaries Startup 1.4.1 Motor current, inlet and outlet pressure, flow rate and inlet filter screen differential pressure are normal; 1.4.2 The sealing part of the relevant equipment is good, the cooling water system is running 173
normally, normally, and the bearing be aring temperature and motor coil temperature a re normal; 1.4.3 Confirm that the interlock protection and automatic control have been put into normal; 1.4.4 Standby pump check valve is tight, with no reverse operation symptoms; 1.4.5 All the vibration components and motor have no abnormal friction sound, and their vibration meets the provision; 1.4.6 Check the bearing box oil level is normal, and there is no oil leakage symptom; 1.4.7 The adjustment of the coupling device to be intact, without shedding; 1.4.8 Inspect the system owned by the auxiliaries has leakage symptoms; 1.4.9 Check the lube oil temperature of each bearing is normal, and the return oil temperature should be within the prescribed range. When manufacturers have no special provisions, implement the standards in the following table:
Bearing type Bearing temperature
Rolling bearing
Sliding bearing
Motor
Machinery
Motor
Machinery
≤80℃
≤100℃
≤70℃
≤80℃
1.4.9 Check the motor temperature rise does not exceed the value in the following table (ambient temperature 40 ℃):
Insulation Class
Class A
Class E
Class B
Class F
65℃
80℃
90℃
115℃
Motor temperature rise 1.4.10 Check that each bearing vibrates normally, and when the manufacturers have no special provisions, implement the standards in the fo llowing table:
Rated speed rpm Vibration mm
3000
1500
1000
0.05/0.06
0.085/0.1
0.1/0.13
750 and below 0.12/0.16
Remarks Motor/Machi ne
2 General Outage Rules of Auxiliaries 2.1 Before auxiliaries stop, contact the relevant posts, carefully consider the impact of the auxiliaries’ outage on the related systems or equipment, and take appropriate safety measures. 2.2 Before auxiliaries stops, withdraw from the standby auxiliaries "automatic" or discharge the 174
self-start "interlocking". 2.3 After the auxiliaries stop, the speed should be reduced to zero, with no reverse operation symptoms. If so, the outlet valve should be closed to eliminate the reverse operation, and it is strictly prohibited to eliminate reverse operation by closing the inlet valve. 2.4 Outage Maintenance of Auxiliaries or Systems 2.4.1 Maintenance of systems or equipment is subject to approval by the duty director and maintenance work sheet is handled. 2.4.2 Take good power-off, pressure relief and isolation measures of equipment. 2.4.3 Disconnect the power supply and control power of the maintenance equipment,. 2.4.4 Close the pump outlet valve, and make sure it is closed tightly. 2.4.5 Close the pump inlet valve and exhaust valve of inlet tube. In the process of closing the inlet valve, in particular close to the fully closed state, should closely monitorthe inlet pressure gauge, and operate slowly, to prevent the outlet valve and other isolation valves connected to the high-pressure system from being loose, resulting in damage to the low-pressure pipe and flange at the inlet part due to overpressure. 2.4.6 Close the bearing cooling water inlet and outlet valve, and open the pump discharge valve and relieve the overflow valve pressure to zero. 2.4.7 Take safety measures as required by the work sheet, and hang safety signs and warning signs. 2.5 Pressure relief operation of pressure vessels and pipes 2.5.1 Close all inlet valves of pressure vessel, and ensure they are tightly closed. 2.5.2 Close all outlet valves of pressure vessel, and ensure they are tightly closed. 2.5.3 Open the drain valve of pressure vessel, and pay attention to the pressure inside the vessel should be lowered. After water drainage has been completed, close the drain valve associated with the vessel, but open the drain valve of the separate trench. 2.5.4 Open the pressure vessel exhaust valve, and confirm that the vessel pressure is fully relieved. 2.5.5 Cut off power supply for the electric valve of the vessel in which external working fluid may enter, cut off the pneumatic valve and make a measure against mistake. 2.5.6 Hang a warning sign of "Prohibition of operation, and in work" on all electrical, pneumatic, manual isolation valves connected with the vessel. 2.5.7 Take overhaul and safety measures as required by the thermal work sheet, and handle the work sheet procedures for permission after the work sheet licensor and the person responsible for work sheets inspect and confirm that saf ety measures are correct, and make relevant records.
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Chapter II Auxiliaries and Systems 1. Lubricating Oil System
1.1. Check and Operation before Startup 1.1.1 Check the lubricating oil system according to General Rules for Auxiliaries ; 1.1.2 Check that all interlock protection tests have been duly conducted and passed. 1.1.3 Check that all instruments and meters are complete, inlet valves of pressure gauges are open and all instruments and meters are working properly; 1.1.4 Use the valve check card to check that all valves of the system are in a proper position; 1.1.5 Shut the oil injection testing valve and oil injection solenoid valve (for the turning g ear) for the emergency trip device and open the outlet check valve for the jacking oil pump; 1.1.6 Check that the oil cooler changeover valve is placed on one side and locked in place, the cooling water system is working well for the oil cooler and the inlet and outlet valves of the cooler is open; 1.1.7 Actuate Actuate the oil cooler by starting starting the the cooling cooling water valve when the lube lube oil reaches reaches 38℃ . 1.1.8 Check and confirm that the generator sealing oil system meets the requirements for commissioning and the loops for the H2 side return oil expansion header, floater oil tank and air exhaust header of the sealing oil system are unobstructed. Check that the lube oil and sealing oil supply valves are closed; 1.1.9 Check and confirm that all oil/water drain valves of the system are shut; 1.1.10 Check the oil level in the main oil tank is normal and ensure oil quality is qualified and there is no accumulated water at the bottom; 1.1.11 Delivery power for the AC auxiliary oil pump, AC startup oil pump and emergency oil pump after confirming they are qualified; 1.1.12 Start Start the the electric electric heater heater to heat heat oil in the the oil tank tank to 35℃ when oil oil temperature temperature drops drops below below 20℃. Then Then switch switch off off the heater heater and allow allow all oil pumps pumps to be starte started. d.
1.2. System Startup 1.2.1 Lubricating oil system Startup 1.2.1.1 Start the smoke exhaust fan for the main oil tank and check that the motor temperature, vibration and sound are normal. Adjust the outlet valve of the fan to maintain the micro-negative pressure around -50Pa. for the main oil tank. Actuate the two smoke exhaust fans in an interlocked mode; 1.2.1.2 Start the AC startup oil pump (or MSP) and AC auxiliary oil pump (or TOP) and check that the motor, bearing and cooling water system have normal temperature, vibration, sound parameters. Check that the inlet pressure of the main oil pump is between 0.098MPa-0.147MPa and the pressure in the bearing lube oil manifold is between 0.137MPa-0.176MPa; 1.2.1.3 Check that the parameters on the temperature and pressure gauges for the main lubricating oil system are correctly indicated; 176
1.2.1.4 Check and confirm that the lube oil system pipe has no leak. View through the peepholes to check oil flow in the bearing of the turbine generator; 1.2.1.5 Check that the oil level in the main oil tank is not lower than -100mm after a refill into the oil system; 1.2.1.6 Trial-run the DC oil pump and actuate th e interlock after it works normally. normally. Then actuate the interlock for the AC auxiliary oil pump. 1.2.2 Jacking Oil Pu mp System Startup 1.2.2.1 Check and confirm that the oil pressure at the jacking inlet exceeds 0.039MPa; 1.2.2.2 Start a jacking oil pump to check that the motor temperature, vibration and outlet pressure are normal; 1.2.2.3 Check that the system has no leak and the oil pressure at the bearing jacking is normal; 1.2.2.4 Actuate the interlock for the jacking o il pump. 1.2.3 Turning Gear Startup 1.2.3.1 Prior to start the turning gear for a new or overhauled generator unit, operate the gear manually in a continuous way to ensure no abnormality; 1.2.3.2 Check and confirm that the lubricating oil system and the jacking oil system are working properly; 1.2.3.3 Start the turning gear via the LCD to locally check that the oil injection solenoid valve for the turning gear opens and meshes normally; 1.2.3.4 Maintain records of such parameters of the turning gear as startup time, startup current, operating current and rotor eccentricity. Inspect the sound from the interior of the gear to check that it is normal; 1.2.4 If adjustment from the maintainer is needed for the throttle valve, bypass valve and overflow valve fitted on the oil turbine in case that the pressure of lube oil supplied by the pressure pump and the main oil pump fails to meet the requirements, or the unit is commissioned for the first time or after an overhaul, the adjustment ad justment must be finished at a time when the turbine is operating stably at 3,000rpm but before the TOP and MSP are deactivated; 1.2.4.1 Adjust the throttle valve to maintain the inlet pressure at the main oil pump of the front bearing box at the required value; 1.2.4.2 Check the leak at the overflow valve and the oil supply manifold for the bearing; 1.2.4.3 Adjust the bypass valve and the throttle valve to meet the requirements for the pressure of the bearing oil supply manifold & oil pump inlet and the leak of the overflow valve; 1.2.4.4 The front bearing box must comply with the following normal pressure values at a rated turbine rotating speed: 1) Inlet pressure of main oil pump: 0.098-0.147MPa 2) Pressure of oil supplied to bearing: 0.137-0.176MPa 3）Outlet pressure of main oil pump: 1.55MPa 1.2.4.5 Lock the throttle valve and overflow valve at the finally adjusted position; 177
1.2.5 After the steam turbine attains to a speed of 3,000rpm, complete the tests while maintaining the main oil pump in normal operation. Then stop the AC auxiliary oil pump and AC startup oil pump and check that the two pumps have not reversed rotation direction and the lube oil pressure is normal.
1.3. System Shutdown 1.3.1 Check and confirm that the seal gland and vacuum system have been suspended from operation; 1.3.2 Check Check and confirm confirm that the the maximum maximum turbine turbine cylind cylinder er temperatu temperature re drops drops below 150℃ ; 1.3.3 Suspend the turning gear for the main steam turbine from operation; then shut down the jacking oil pump; 1.3.4 See to it that the sealing oil system works normally; 1.3.5 Release the DC oil pump of the main steam turbine from interlock; 1.3.6 Shut down the MSP and TOP as the cylinder temperature changes; check the rising oil level in the main oil tank to prevent an overflow; 1.3.7 Shut down the cooling water inlet and outlet valves for the oil cooler to disable the cooling water system for lube oil; 1.3.8 Shut down the smoke exhaust fan for the main oil tank; 1.3.9 After the turning gear is stopped, start the auxiliary oil pump immediately to cool the bearing once the bearing metal temperature rises aga in and exceeds the limits;
1.4. Operation Adjustment and Maintenance 1.4.1 In normal unit operation, ensure that the turning gear, g ear, jacking oil pump, AC auxiliary auxiliary oil pump and AC startup oil pump work properly. The parameters must be controlled within the following normal range and adjusted in case of any deviation. In case of an alarm, check for the cause and correct the abnormality. If the trip value is attained but there is no trip operation, shut down the system manually;
Item Item
Unit nit
Norm Normal al Value alue
Alar Alarm m Value alue
Trip
Lube Oil Pressure
MPa
0.137-0.176
0.115
0. 0.07
Lube Oil Temperature
℃
40-50
Inlet Oil Pressure of Main Oil Pump
MPa
0.098-0.147
-
-
Outlet tlet Oil Pres Press sure ure of Main Oil Pump
MPa
1.55
-
-
Inlet Oil Press essure of Jacking Oil Pump
MPa
0.03
-
-
Outl Outlet et Oil Oil Pres Pressu surre of Jacki acking ng Oil Oil Pum Pump
MPa
1212-16
-
-
Jacking Oil Pressure of Different Bearings
MPa
12-16
-
-
Micro-Negative Pre Pressure of Main Oil Pump ump
MPa
-50
-
-
-
1.4.2 Adjustment of Bearing Lube Oil Temperature: Temperature: 1.4.2.1 When the turning gear is in operation, the bearing lube oil temperature must be controlled 178
between 27 27-40℃ ; 1.4.2.2 When the turbine reaches the synchronized rotating speed, the bearing inlet oil temp temper eratu ature re mus mustt be be at leas leastt 38℃ ; 1.4.2.3 When the turbine is in normal operation, the bearing lube oil temperature must be cont contro roll lled ed bet betwe ween en 4040-50 50℃ . 2. EH Oil System
2.1. Check before EH Oil System S ystem Startup 2.1.1Finish the operations as specified by General Rules for Pre-Startup Check of Auxiliaries and
System ; 2.1.2 Check and confirm that the oil level in the EH oil tank is slightly higher than the normal level. Confirm that the oil is limpid and free of impurities, all gauges and instruments (including differential pressure gauge) are complete and have been commissioned and the oil level gauge has correct and reliable indication; 2.1.3 Use the valve check card to check that all valves of the system are in a proper position; 2.1.4 Check that the control power supply has been correctly provided and the signals are normal; 2.1.5 Check and confirm that all interlock protection tests on the EH oil system have been passed and the system is correctly commissioned; 2.1.6 Check that the service water system is operating normally. Then open the inlet and outlet valves of the EH oil cooler and commission the water side of the cooler to operation; 2.1.7 Ensure that the energy accumulator has a normal nitrogen pressure (8MPa), otherwise conduct a nitrogen makeup; 2.1.8 Measure and ensure the motors of all oil pumps are satisfactorily insulated before power supply is delivered.
2.2. EH Oil System Startup 2.2.1 Startup of EH Oil Circulating Pump 2.2.1.1 Open the manual inlet valve of the EH oil circulating pump to refill the pump with oil; 2.2.1.2 Start an EH oil circulating pump to check that it works normally, has no leak and has a normal oil tank level, otherwise conduct an oil makeup; 2.2.1.3 Check that the EH oil circulating pump has a normal outlet pressure and the safety valve works properly; 2.2.1.4 Fill the EH oil regeneration devices with oil to displace the air inside; put an oil regeneration device into operation to check that the differential pressure is normal; 2.2.1.5 Fill the EH oil coolers with oil to displace the air inside; put a group of oil coolers into operation and monitor closely the oil level in the tank to prevent the EH oil from seeping into the cooling water system; 2.2.1.6 After the system is duly checked, put another EH oil circulating pump into operation for standby; 179
2.2.1.7 The EH circulating oil purifier must be continuously operated for at least over 4 hours. 2.2.2 Start the electric heater for EH oil automatically. Check that the oil temperature in the tank exceeds exceeds 32℃, otherwise otherwise the electric electric heater must be be started started in the interloc interlock k mode; mode; 2.2.3 Startup of EH Oil Pump 2.2.3.1 Open the manual inlet valve of the EH oil pump to refill it with oil; 2.2.3.2 Start an EH oil pump to check that it works properly, has not leak and the outlet pressure is maintained around 11.2MPa; 2.2.3.3 Check that the EH oil pump has normal outlet pressure and the EH oil pressure of the energy accumulator is normal. Check that no alarm is sounded when there is a differential pressure at the strainer for the outlet o f the EH oil pump. The oil temperature in the oil cooler must be capable of automatic adjustment; 2.2.3.4 Ensure that the EH oil pipe system has been cleaned of air; 2.2.3.5 Put another EH oil pump into operation after a thorough check.
2.3. System Shutdown 2.3.1 Ensure that all shutdown conditions are met; 2.3.2 Release the EH oil system from automatic standby mode and shut down the pump; 2.3.3 Shut down the circulating pump; 2.3.4 Shut down the oil cooler.
2.4. Monitoring and Adjustment of System Operation 2.4.1 Check that the oil level in the EH oil tank is slightly higher than the low level alarm value (30mm-50mm). The oil level must not be too high, otherwise an overflow will occur in case of a trip operation. If the oil level drops, identify and rectify the cause promptly. When necessary, contact the maintainer for a refill; 2.4.2 Check that the following parameters of the EH oil pump are normal: bearing vibration, temperature, internal noise and outlet pressure. Check that the pressure of the EH oil system is between 10.7MPa and 11.7MPa. Ensure that the differential pressure at the strainer of the outlet of the pump is normal. If the differential pressure rises by 0.5MPa at the strainer, contact the maintainer for a repair or replace the strainer; 2.4.3 Check that the following parameters of the circulating oil pump are normal: bearing vibration, temperature, internal noise, outlet pressure and EH oil system pressure; 2.4.4 Check that the pipes and equipment of the EH oil system have no leak; 2.4.5 2.4.5 Chec Check k that that the EH oil temper temperatu ature re is betwee between n 32℃ and 54℃ and the automa automatic tic oil temperature adjustment for the oil cooler is normal. In case that the oil temperature comes to 54℃ and above and a manual adjustment is ineffective, commission the standby oil cooler, isolate the faulty oil cooler and submit it to the maintainer for cleaning a nd re-commissioning; 2.4.6 Check that the nitrogen charging pressure for the high-pressure energy accumulators is sufficiently normal. If the charging pressure drops, scatter the accumulators and recharge one at a time; 180
2.4.7 Check that the visual mechanic indicator of the air filter is triggered. If it is triggered, replace it; 2.4.8 Check and confirm that the pressure of the circulating system is less than 1MPa; 2.4.9 Before isolating the small steam turbine for an overhaul during the operation, close the EH oil shutoff valve leading to the small steam turbine; 2.4.10 Fulfill the periodic changeover and testing tasks as per the requirements in Rules for
Periodic Changeover and Testing of Equipment. 2.4.11 Limits Limits of Operational Parameters of o f EH Oil System
Item
Unit
Normal
Upper
Lower
Value
Limit
Limit
Remarks 30mm higher
EH Oil Tank Level
mm
than low level alarm value
EH Oil Tank Temperature
℃
32-54
MPa
＜0.5
MPa
＜0.138
MPa MPa
10.7 10.7-1 -11. 1.7 7
MPa
8±0.2
MPa
14±0.2
MPa
0.5±0.1
Differential Pressure at Inlet/Outlet of Strainer of EH Oil Pump Differential Pressure at Strainer of EH Regeneration device EH Oil Oil Pres Pressu sure re Nitrogen Charging Pressure for High-Pressure Energy Accumulator Operating Value of Overflow Valve of EH System
The turbine trips at 7.8 Nitrogen Charging
Operating Value of Overflow Valve at Outlet of Circulating Pump
2.5. System Accidents Treatment 2.5.1 Solution to EH Oil Pressure Fluctuation: 2.5.1.1 In case of an EH oil fluctuation, check if the EH oil safety valve and the check valve at the outlet of the standby promptly are working properly. If necessary, contact the maintainer for a solution; 2.5.1.2 Check the oil level in the EH oil tank; if necessary, necessary, contact the maintainer for a refill; 2.5.1.3 If necessary, change over to the standby pump; 181
2.5.1.4 If the EH oil pressure fluctuation fails to be corrected and affects the normal unit op eration, report it and ask for a shutdown; 2.5.2 Treatment to EH Oil Pressure Drop 2.5.2.1 Symptoms 1) The CRT or the local gauge indicates a drop in EH oil pressure; 2) The CRT indicates a low EH oil pressure. 2.5.2.2 Causes: 1) Low oil level in the EH oil tank; 2) Leak in the EH system; 3) Fault of the EH oil pump; 4) Dirt retained on the strainer at the inlet/outlet of the EH oil pump; 5) Misoperation of the safety valve of the EH oil system; 6) Un-tight sealing of the check valve at the outlet of the standby EH oil pump 2.5.2.3 Treatment: 1) When the oil pressure drops to the interlocked pump value, check and confirm that the standby pump is correctly started by interlock, otherwise start it manually; 2) If the commissioning of 2 EH oil pumps still fails to maintain the pressure, prepare for a shutdown; 3) When the shutdown protection value is reached, the protection operation must be normal; otherwise, enforce a shutdown manually; 4) In case of a leak of the EH oil system, try to isolate the leak spots while maintaining the EH oil pressure. Contact the maintainer for a prompt repair and refill. If the isolation measure fails in face of a serious leak, report it and ask for a shutdown; 5) Check the operation of the safety valve. In case of a misoperation, contact the maintainer for a prompt repair; 6)
If the differential differential pressure at the strainer of the operating pump is too high, shut down the
pump and start up the standby pump. Contact the maintainer for a repair; 7) In case of a malfunction of the operating pump, change over to the standby pump and contact the maintainer for a repair. repair. 2.5.3 Treatment to EH Oil Leak: 2.5.3.1 If a system leak is confirmed, locate the leak spot promptly and evacuate operators from the site; 2.5.3.2 If the leak spot is inside the oil cooler, change over to the standby oil cooler and isolate the leaking cooler. Contact the maintainer for a repair. 2.5.3.3 In case of a serious leak which hinders the maintenance of the EH oil level, contact the maintainer for a prompt refill and prepare for a shutdown; 2.5.3.4 If the oil pressure drops as a result of a low level, solve the problem accordingly. 2.5.4 Treatment to EH Oil Level Drop 182
2.5.4.1 Generally, a drop in the EH oil level results from a leak in the system pipes or oil cooler. Check for, locate and isolate the leak spot; 2.5.4.2 If the o il level drops too quickly, contact the maintainer for a prompt refill; 2.5.4.3 If the normal operating oil level fails to maintained, prepare for a shutdown. 3. Unit Bypass System
3.1. Pre-Startup System Check 3.1.1
Check that the high & low bypasss are shut down;
3.1.2
Push the “valve check card” button to check that all valves are in the correct position;
3.1.3
Check that the condensate system, feed water system, instrumentation air system and the
vacuum system for the main steam turbine are working normally; 3.1.4
Check that the attemperating water for the high/low bypass has a normal pressure and the
drain valve for the attemperating water pipe fo r the high/low bypass is closed. Close the vent valve after air is discharged. Ensure that the manual isolating valve is open and there is no leak; 3.1.5
Check that the control air supply sup ply for the high/low bypass is normal (pressure: 0.6-0.8MPa);
3.1.6
Check that the isolating valves for the front and rear heat pipes of the steam converter
valve for the high bypass are open; 3.1.7
Check that the front and rear drain traps of the steam converter valve for the low bypass
are started and the water level in the drain trap is normal; 3.1.8Order the thermal engineering operator to provide control air supply for the pneumatic pressure relief valve for the high/low bypass, the attemperating water control valve and the front and rear steam trap valves for the steam converter valve of the low bypass. Check that the air supply has a pressure between 0.6MPa and 0.8MPa and the pneumatic control part is reliably connected to the valve part; 3.1.9
Check and confirm that the isolating valve is open to the air supply for the high/low bypass.
3.2. System in Operation 3.2.1 3.2.1.1
Control Mechanism of High bypass Boiler is ignited and the pressure rises, press the “Auto-startup-On” button to switch the
bypass system to the minimum opening position. The high bypass will be maintained at a minimum opening position (Ymin_HP 5 ％). At the startup stage, the high-pressure bypass valve must not be less than this opening in order for a small amount of steam to circulate for the cooling of overheaters and reheaters; 3.2.1.2 After the main steam pressure reaches 2.0MPa, the high bypass changes over to pressure rise mode. The settings of the pressure controller for the high bypass are determined by calculations. The pressure settings rise at different rates (0.04MPa/min in cold state, 0.08MPa/min in warm state, 0.14MPa/min in heated state and 0.18MPa/min in overheated state) to different final pressures (Psync_HP: 5.9MPa in cold state, 8.52MPa in warm state, 8.52Mpa in heated state and 12.8MPa in overheated state). Meanwhile, the low bypass is in constant pressure control mode 183
with a pressure setting of 1MPa; 3.2.1.3
When the main steam pressure attains to the final pressure, the high bypass changes
over to constant pressure control mode, where the high bypass is maintained in automatic mode with a pressure setting of Psync_HP. After steam is admitted into the turbine, the high bypass will be gradually shut down as the main steam pressure drops; 3.2.1.4
When the high bypass is shut down and “turbine synchronized” and “cylinder transfer
completed” signals will be emitted and the high bypass will change over to follow mode, where the steam pressure fluctuates with the boiler load. The pressure setting for the high bypass equals to the actual actual pressure pressure value value plus the offset offset value value (△ P_follow_HP( P_follow_HP(0.4MP 0.4MPa)) a)) to ensure ensure the shutdown shutdown of the high bypass. When the main steam pressure rises abruptly (the rate of pressure rise exceeds max_gradient_follow_HP(0.6MPa/min)), retain the pressure settings and abandon the offset value. The pressure control valve for the high bypass actuates control pressure until the valve is reclosed and reverted to follow mode; 3.2.2
Control Low bypass
3.2.2.1 After the boiler is ignited, the low bypass must adopt minimum opening control. After the boiler is ignited and the pressure rises, press the “Auto-startup-On” button to switch the bypass system to the minimum opening position. The high bypass will be maintained at a minimum opening position (Ymin_HP 5％); 3.2.2.2
The pressure of the low bypass increases as the opening of the high bypass and the
main steam pressure rise. The two low bypass control valve will be maintained at minimum opening until the reheated steam pressure attains to 1MPa and the low bypass switches to the constant pressure control mode, where the low bypass will be still open in order to maintain the pressure settings at 1MPa; 3.2.2.3 As the turbine speed escalates, the synchronization and load increase, the low bypass closes and the minimum opening mode is abandoned. When “Load-UP” signal is emitted, the settings of the low bypass pressure controller change from 1MPa to 0.5MPa at a rate of 2MPa/min until the interceptor valves are all open and all low bypasses are closed; 3.2.2.4
When the “cylinder transfer completed” signal is emitted, the low bypass synchronously
switches to the follow mode with the high bypass; 3.2.2.5
In the follow mode, the settings of the low bypass pressure controller equal to the actual
reheated pressure plus the offset value (0.2MPa). When the main steam pressure rises abruptly (the rate of pressure rise exceeds max_gradient_follow_HP(0.6MPa/min)), retain the pressure settings and abandon the offset value. The pressure control valve for the low bypass is actuated and starts to control steam pressure until until the two low bypass valves are reclosed and reverted to follow mode; 3.3
The bypass system will execute the following operations when the turbine trips at a motor
load of 6-90MW: 3.3.1
The bypass will be fast-opened; 184
3.3.2
The high/low bypass pressure is controlled in minimum opening mode;
3.3.3
The operating mode of high/low bypass is switched to constant pressure control mode;
3.3.4
The settings for the high/lo
w bypass pressure controllers are retained; 3.4
The bypass system will execute the following operations when the turbine trips at a motor
load of 90MW and above: 3.4.1
The boiler MFT is started in the event of a turbine trip;
3.4.2
The bypass system will be switched to pressure control mode and the settings equal to t o the
main steam pressure prior to the trip; 3.5
Load-Down of High/Low Bypass
3.5.1
When the unit is unloading, the high/low bypass is maintained in follow mode;
3.5.2
When the motor load drops below 35MW and the “Load Down” signal is emitted, the
high/low bypass is switched to constant pressure control mode and the offset value in the follow mode is abandoned. The new pressure settings are respectively 5.9MPa for the high bypass and 0.4MPa for the low bypass. 3.5.3
The high/low bypass pressure controller works at a pressure variation rate of 0.3MPa/min.
4. Gland Sealing System
4.1. Pre-Startup Check and Operation 4.1.1 Conduct a thorough check of the system as per the requirements in Commissioning Rules
for Auxiliary Equipment; 4.1.2 All tests have been conducted and passed prior to the startup; 4.1.3 Ensure that the auxiliary steam system, instrumentation air system, condensate system and circulating water system have been commissioned and a re working well; 4.1.4 Ensure the turning gear has been operating for over 1 hour and the eccentricity is less than 0.076mm; 4.1.5 4.1.5 Ensure Ensure that that the overh overheat eat of the the seal gland gland steam steam excee exceeds ds 50℃ ; 4.1.6 Ensure that the temperature difference between the feed steam pressure of the high/medium pressure pressure seal gland gland and the the rotor metal metal is less less than 110 110℃ (allowable (allowable temperat temperature ure for cold cold-state startup); 4.1.7 Ensure that the setting for seal gland steam temperature of the low pressure cylinder is 150℃; 4.1.8 Never feed attemperating water to the low-pressure seal gland before the seal gland is properly commissioned. This is meant to prevent water inclusions in seal gland steam or the cylinder; 4.1.9 Confirm that the seal gland fan and the pipes have been drained; 4.1.10 Confirm that the seal gland steam system have proper drainage; 4.1.11Confirm that the turning gear has been actuated for the turbine and the circulating water 185
system, condensate system and auxiliary steam system have been properly commissioned; 4.1.12 Refill the sealing water pipe for the seal gland heater with water and vent the air. Switch the backwater to the condenser; 4.1.13 Commission the water side of the seal gland heater to operation; 4.1.14 Confirm that all control valves of the gland sealing system have proper air supply, all instrumentation isolating valves have been opened and liquid level gauges and negative pressure gauges of the seal gland heater have been commissioned. All of these devices must be in a manual mode; 4.2. System Startup 4.2.1 Select the correct steam supply for the seal gland depending on the turbine metal temperature; 4.2.2 Heat Pipe Transferring Auxiliary steam to Pipes in Seal gland Steam Control Station 4.2.2.1 Check that the heat pipe transferring auxiliary steam to pipes in the seal gland steam control station has proper drainage and the steam temperature matches the rotor metal temperature; 4.2.2.2 Open the electrically-operated isolating valve fully, which connects the auxiliary steam header to the shaft steam; open the isolating valve partially, which connects auxiliary steam to the seal gland steam; 4.2.2.3 Open the isolating valve fully, which connects auxiliary steam to the seal gland in 1 0min; 4.2.2.4 After a vacuum is formed in the condenser, switch auxiliary steam to the seal gland steam trap and maintain the trap in constant draining state. 4.2.3 Heat Pipes of gland sealing system 4.2.3.1 Check that the system has proper drainage; 4.2.3.2 Check that the valves connecting the seal gland steam manifold to the seal gland sections in different cylinders are closed; 4.2.3.3 Check that the seal gland steam control valve is in manual mode and is closed. Actuate the electrically operated isolating valve connecting auxiliary steam to the seal gland steam control valve. The isolating valve guides the steam through the orifice plate into the heat pipe of the seal gland steam system until the steam reaches the seal gland steam valves of the different cylinders. 4.2.4 The seal gland steam must be commissioned as per the following principles: Pump a vacuum prior to a cold-state startup and commission the seal gland steam before the high-pressure cylinder is preheated. If a high-pressure cylinder is not preheated, commission the seal gland steam 30 minutes before the unit rolls; in a warm/heated state, commission the seal gland steam before pumping the vacuum; 4.2.5After seal gland steam is commissioned, start the seal gland fan immediately. Check that the fan vibration, vacuum degree of the seal gland heater and inlet/outlet water temperature rise are normal. Commission the shaft-seal fan in an interlock. A negative pressure of 95-99KPa (a) must be maintained for the return steam pipe for the steam seal; 186
4.2.6 After the pipe heating process, commission the control valve of the low-pressure seal gland steam supply station in an automatic mode. Check that the control valve works properly and the seal gland steam manifold has normal pressure; 4.2.7 Check and open the seal gland steam leak-off valves for the cylinders of the main steam turbine; 4.2.8 Commission the low-pressure seal gland steam supply, overflow valve and the low-pressure seal gland attemperating water to deliver seal gland overflow back to the condenser. Check that seal gland steam manifold pressure is maintained at 0.124~0.127 (a) MPa. The temperature of the seal gland steam is respecti respectively vely 150-260 150-260℃ in the cold state and 208 208-375 -375℃ in the the hea heate ted d sta state te.. 4.2.9 Open all the steam supply valves to all seal gland sections of the high/medium pressure cylinders to confirm that no steam leaks from the seal gland into the atmosphere. Otherwise, adjust the vacuum degree of the seal gland heater or the pressure of the seal gland manifold until no external leak is detected; 4.2.10 When the unit load exceeds 25% of the rated load, check that the seal gland steam is automatically switched to self-sealing mode. At this stage, ensure that the reheated cold section provides sealing steam, otherwise, close the control valve for low-pressure seal gland steam supply and maintain the pressure of the seal gland manifold until the control valves are all closed. When the load rises to 60% and above, the steam volume leaked through the shaft end of the high/medium-pressure cylinders into the steam supply manifold has exceeded the steam supply volume required for the seal gland of low-pressure cylinders. At this stage, the control valves for all the steam supply stations will be automatically closed, and the control valve for the overflow station will be automatically opened to discharge excess steam into #8A low-pressure heater in order to maintain the steam pressure of the steam seal manifold at 0.13MPa (a); 4.2.11 4.2.11 When the seal gland steam is in self-sealing operation, monitor the seal gland ove rflow and check that it is operating normally. After it works normally, close the electrically operated check valve connecting the cold reheater to the gland sealing system; 4.2.12 Before the main steam turbine is synchronized, commission seal gland steam from the small steam turbine. Open the bypass valve of the steam vent valve for the small steam turbine to pump a vacuum; 4.3. System Shutdown 4.3.1 While the unit is being shut down, if the unit load drops below 25%, check the seal gland steam supply and ensure that it is automatically switched to low-pressure seal gland steam supp ly; 4.3.2 After the unit trips and shuts down and the vacuum degree of the condenser reaches 0 while the turning gear is working normally, close the valves for the seal gland steam and release the interlock for and shut down the seal gland fan; 4.3.3 Release the sources of seal gland steam supply and the control valves for seal gland attemperating water from the automatic mechanism. Close the steam supply, attemperating water control valve and the front and rear isolating valves; 187
4.3.4 Open the steam trap valves for the seal gland steam system. 4.4. Operation Monitoring, Adjustment and Maintenance 4.4.1 Check if the bearing return oil has water inclusion on a regular basis to determine if the pressure settings for seal gland steam are too high, and if the seal gland steam has proper drainage support; 4.4.2 Check that the pressure in the seal gland steam manifold and the operation of all feed steam control valves & overflow valves are normal. Monitor the pressure settings for the seal gland steam to prevent too low a value which may affect the vacuum degree; 4.4.3Check that the temperature of the seal gland steam manifold and the temperature control of the seal gland steam are normal. Monitor the seal gland temperature of the low-pressure cylinder to prevent a breakdown of the temperature control valve, which may cause water inclusions in the seal gland; 4.4.4 Monitor the fan seal gland heater to ensure normal operation. Internal negative pressure of the seal gland heater must be maintained between 95～99KPa (a) to prevent seal gland steam from outflow. 4.4.5 Monitor the seal gland heater to ensure a normal no rmal water level. If no high/low-level alarm signal is emitted by the seal gland heater, drainage from the heater must be discharged via the sealing water pipe. The water seal in the sealing water pipe must be working normally. Ensure the inlet/outlet water temperature of the seal gland heater is normal; 4.4.6 Fulfill the periodic changeover and testing tasks to ensure normal operation; 4.4.7 Adjustment and Operation of Control valves at Different Control Stations
Steam Seal
High-Pressure Steam Auxiliary Steam
Overflow
Manifold
Supply Control
Supply Control
Control
Pressure
Station
Station
Station
0.124
Closed
Open and adjusted Open and
0.127
Closed
0.13
Closed
Closed
0.118 0.118
Open and adjusted
Closed
adjusted
Operation
Vacuum Closed
pumping (cold startup)
Closed
Rated load: Up to 25% Self sealing
Closed
Load rejection Vacuum
0.118 0.118
Open and adjusted
Closed
Closed
pumping (warm startup)
4.5. Common Faults and Simple Solutions
188
Fault
Cause
Fault Treatment
1) The pressure control valve for the steam supply is not tightly closed
Manifold Overpressure
2)
External
sources
steam
enters
the
system
3) The seal gland has undetected
leak
spots
1) Check the control signals and the tightness of the valves. If insufficient tightness is confirmed, report it to the manufacturer
or
the
accessory
manufacturer 2) Locate the external steam source and cut off steam supply
3) Locate the leak spot nearest to the seal gland 1) Open the outlet valve of the seal
1) The outlet portal of
Steam Leak from Seal gland
gland fan
the seal gland fan is
2) Adjust the cooling water amount for
closed
the seal gland heater to maintain the
2) There is too small a
pressure in the steam seal heater
quantity
below 95KPa(a)
of
cooling
water for the seal gland
3) Tilt the return steam/gas pipe
heater
towards the steam seal reheater until a
3)
The
steam/gas
return pipe
gradient of 1/50; when the return
is
steam/gas is delivered into inlet pipe
irrationally arranged,
for the steam seal heater, try not to let
or there is a drainage
the steam/gas enter from the lower part
problem at the low
of the pipe
point
4) Keep a proper drainage at the low point
1) The nozzle of the attemperator
Low-Pressure Steam Overtemperature
is
clogged
1) Clean the nozzle
2) The water filter is
2) Clean the water filter
clogged
3) Check the power supply and
3) The water spray
control signals for the control valve
control
valve
does
not function normally Low-Pressure Steam
The
water
spray
control valve is not 189
1) Check the power supply and control signals for the control valve
Undertemperature
tightly closed
2) Check if the control valve has an internal leak; if it is the case, contact c ontact the manufacturer or the accessory manufacturer for a repair
5. Vacuum System
5.1. Pre-Startup System Check 5.1.1Finish the operations as specified by General Rules for Pre-Startup Check of Auxiliary Equipment and System. Ensure that all systems related to vacuum formation are duly checked and proved to be working normally; 5.1.2 Check that the drain valve for the steam/water separator is closed, the water level gauge is working properly and the drain valve at the bottom of the vacuum pump is closed; 5.1.3 Check and confirm that the service water system and condensate system have been satisfactorily commissioned; 5.1.4 Check that the makeup water pressure for the steam/water separator is normal. Open the makeup water bypass valve to make up the water level to normal. Then launch the automatic control mechanism for the water level; 5.1.5 Check that the circulating water system works normally and the open circulating water system have a normal pressure; 5.1.6 Open the cooling water inlet/outlet valve of the cooler to replenish it with water; 5.1.7
Check
that
the
instrumentation
manifold
has
normal
pressure
and
the
pneumatically-controlled butterfly valve at the inlet of the vacuum pump has normally working control air supply; 5.1.8 Check and confirm that the vacuum breaker of the condenser is closed and the vacuum system meets the commissioning conditions; 5.1.9 Check that the seal gland steam system is commissioned and works normally while the unit is in a heated state (in the case of a cold state, pump the vacuum before commissioning the seal gland, and vice versa in the case of a heated state); 5.1.10 Check and confirm that the motor of the vacuum pump has sound insulation before electric power is fed to the control power supply of the local control cabinet; 5.1.11Ensure that the seal gland steam system is commissioned and works normally while the unit is in the heated state (in the case of a cold state, state , pump the vacuum before commissioning the seal gland, and vice versa in the case of a heated state); 5.1.12 Check and confirm that all manual valves are prepared for actuation. Open the manual check valve at the inlet of the vacuum pump unit;
5.2. System Startup 190
5.2.1 Check and confirm that the vacuum pump meters and condenser vacuum transducers are correctly commissioned; 5.2.2 Start a vacuum pump and the pneumatic valve at the inlet of the pump must be automatically opened. The vacuum degree of the condenser rises gradually; 5.2.3 Check that the sound, vibration and temperature of the vacuum pump are normal. Keep records of the current; 5.2.4 Check that the steam/water separator of the vacuum pump has a normal water level; 5.2.5 Switch the other vacuum pumps to the automatic mode after they are confirmed as normal. Actuate the pumps in the manual mode;
5.3. System Shutdown 5.3.1 The shutdown of the vacuum vacuu m system must meet the following conditions: 5.3.1.1 The rotating speed of the turbine has dropped to zero and the turning gear has been commissioned; 5.3.1.2 The condensate pump must start another recirculation process and the condensate polisher has been decommissioned; 5.3.1.3 5.3.1.3 The The turbine turbine must must have have an exhaust exhaust steam steam tempera temperature ture below below 47℃ ; 5.3.1.4 The tempera temperature ture of the first first stage stage of the turbine turbine metal metal is less less than 150℃ ; 5.3.2 Vacuum Breaking 5.3.2.1 Stop the vacuum pump and start the vacuum breaker to break the vacuum; 5.3.2.2 In the event of an emergency unit shutdown, reduce the idle time by breaking the vacuum promptly; 5.3.3 If a vacuum pump needs to be stopped while the unit is in operation, check and confirm that the pneumatic valve at the inlet of the pump is shut and the condenser has a n ormal vacuum. If the vacuum pump needs to be stopped for an overhaul, isolation measures must be taken accordingly;
5.4. Operating Monitoring and Maintenance 5.4.1 Check that the vacuum pump has normal vibration, no friction, no abnormal noise and normal motor current; 5.4.2 Monitor the steam/water separator of the vacuum pump to ensure a normal water level and normal makeup water pressure. Ensure that the cooler works reliably; 5.4.3 Check and monitor the condenser to ensure a normal vacuum for the condenser and no leak for the system. 5.4.4 Check that the steam/water separator has normal discharge on the top;
5.5. System Fault Treatment 5.5.1 Drop in Condenser Vacuum 5.5.1.1 Symptoms 1) Vacuum indications of local condensers and condensers in the centralized control station; 2) The temperature of the exhaust steam rises and the temperature of the condensate rises; 191
3) Under the same load, the steam flow rate increases and the pressure at velocity stage rises; 4) The vacuum drops to to 13.5KPa 13.5KPa (a), or the exhaust exhaust steam steam rises rises to 80℃ . An An alarm alarm is sounded. sounded. 5.4.1.2 Causes: 1) The circulating water pump has a failure or trip; the butterfly valve at the outlet of the pump has a smaller opening or is fully closed; or the inlet and outlet circulating water valves for the condenser are closed by mistake, causing a decrease or cutoff of circulating water supply; 2) The stainless steel pipe of the condenser is not clean; 3) The mechanical vacuum pump has a failure or trip; 4) The vacuum breaker is opened by mistake, or is not tightly closed; the pipes of the vacuum system and other systems have a failure or leak; or the valve of the vacuum system has an external leak. 5) The steam supply pressure of the seal gland drops perceptibly and the water level and negative pressure of the seal gland heater are abnormal; 6) The hot well of the condenser has too high a water level; 7) The vacuum system of the small steam turbine develops a leak; 8) The explosion vent in the low-pressure cylinder of the main and small steam turbines develops a crack. 5.4.1.3 Treatment 1) If a drop of condenser vacuum degree is detected, check up promptly the indications of the vacuum gauges and confirm the drop by comparative studies of temperature rises of the exhaust steam; 2) Conduct the following checks on the circulating water system: a) Check if the circulating water pressure is normal; it is too low, check if there is any leak or blockage in the circulating water system; b) Check if the water level at the inlet of the circulating pump; if it is too low, promptly start the filth removal unit; c) Check if the circulating water temperature rises; d) If the inlet water pressure and the outlet water temperature of the condenser rise, there must be a filth accumulation in the pipe system. Clean the steel pipe of the condenser at this stage; e) Check that the circulating water pump functions properly, otherwise start the standby pump. 3) Check the vacuum system and carry out isolation steps as follows: a) Check that the vacuum pump functions properly; b) Check that the vacuum system has a leak; c) Check that the vacuum system pipes and the low-pressure continuous vent pipes of the low-pressure heater have been damaged; d) Check if the vacuum breaker b reaker is tightly shut and if the sealing water is normal; e) Check if the steam supply pressure for the seal gland is normal, if high/low pressure steam 192
supply control valves and overflow valves of the seal gland is working properly and if the sealing water for the seal gland heater is working properly. If there is a fan failure or low negative pressure of the seal gland heater, the standby fan may be commissioned; f) Check if the small steam turbine steam vent system is functioning normally; if necessary, start the electric pump, shut down the small steam turbine and close the steam vent butterfly valve; 4) Check if the condensate pump has properly working sealing water, if the pump develops a leak and if the water level is too high; 5) If the condenser vacuum drops to 13.5KPa (a), the standby vacuum pump will be automatically started; otherwise, start the pump manually. If the vacuum keeps dropping, reduce the load to maintain the vacuum. When the vacuum drops to 25.3KPa (a), the protection mechanism will trip, otherwise, manually trip and shut d own the pump; 6) While the vacuum is dropping, observe closely the exhaust steam temperature for the low-pressur low-pressure e cylinder cylinder.. When the temperat temperature ure rises rises to 47℃ , the water water spray spray valve will will be commissione commissioned; d; when the temperatu temperature re reaches reaches 80℃ , the valve valve will will be fully fully opened; when the temperature temperature rises rises up to to 107℃ , the protecti protection on mechanism mechanism will will trip trip to shut shut down the the machine; machine; 7) When the vacuum drops to 0.07MPa, the small steam turbine will trip; otherwise shut it down manually. 6. Circulating Water System
6.1. Pre-Startup System Check 6.1.1 ；Finish the operations as specified by General Rules for Pre-Commissioning Check of
Auxiliary Equipment and the System ; 6.1.2 Check that the static interlock test on the circulating water p ump is passed; 6.1.3 Check and confirm that the gate valve of the pump is open and the water level in the intake chamber is normal; 6.1.4 Check that the service water system has been commissioned to provide reliable water supply; 6.1.5 Check that the lubricating & cooling water has been commissioned for the circulating pump and cooling water has been commissioned for the air cooler of the pump motor; 6.1.6 Check that the lubricating and cooling water supply for the pump bearing has a normal flow rate, pressure and return water supply; 6.1.7 Check and confirm that the motor bearing lube oil for the circulating pump has acceptable quality and oil level; 6.1.8 Check that the hydraulic oil station for the butterfly valve at the outlet of the circulating pump has a normal oil level and acceptable oil quality; 6.1.9 Start the hydraulic oil pump of the butterfly valve at the outlet of the circulating pump to check that the system has normal n ormal pressure. Commission the control interlock for the oil pump; 193
6.1.10 Before starting the first circulating pump, check that the butterfly valve at the pump outlet operates smoothly and normally with no jam; 6.1.11 Check and confirm that the strainer of the filth removal un it has a normal water head on the two sides of strainer; 6.1.12 Check and confirm that the vent valve of the circulating pump is open when the pump is started; 6.1.13 Check that all the drain valves on the circulating water pipe are closed, the vent valves of the water chamber of the high/low pressure condensers are open and all vent valves of the circulating water valves are open; 6.1.14 Check that all the inlet and outlet valves for circulating water for condensers.
6.2. Startup of Circulating Water System 6.2.1 Check and confirm that all precond itions for the startup of the circulating water pump are met; close the butterfly valve at the outlet of the pump and configure the control mode as manual mode; 6.2.2 Open the outlet valve of the pump at a 15% opening, wait till the vent valve gives off water and shut it off. After the venting process in the water chamber is completed, close all vent valves in the chamber; 6.2.3 Start up the circulating pump and check that the following parameters are normal: pump current, rotational direction, vibration, sound, lubrication and cooling water flow rate; 6.2.4 Commission the control interlock for the outlet valve for the pump and confirm that the valve is automatically opened at a full opening; 6.2.5 Shut down the circulating pump and start up the vent valve; 6.2.6 After the circulating pump works stably, check that the circulating water manifold has normal pressure; 6.2.7 Start the second circulating water pump if necessary; 6.2.8 When the second circulating water pump is started, the butterfly valve at the outlet may be directly configured as automatic mode; 6.2.9 Check that the temperature of all the pump bearings is normal; 6.2.10 Check that the coil temperature of the pump motor is normal; 6.2.11 Check that the sound and vibration of all the parts of the pump motors are normal; 6.2.12 Configure the filth removal unit of the circulating water system and the dredge pump in the pump room as automatic mode; 6.2.13 Conduct a cross examination to confirm that the circulating water system and equipment function reliably. reliably.
6.4. Shutdown of Circulating Water System 6.4.1 First, shut down the open circulating water pump; then shut down the other pump; 6.4.2 Release the standby circulating pump from the interlock; 6.4.3 ；Check and confirm that the vacuum degree of the condenser drops to zero and the gland sealing system is shut down; 194
6.4.4 Check and confirm that the exhaust steam temperature of the low-pressure cylinder is below 50℃; 6.4.5 Check and confirm that all users of the circulating water system agree to shut down the system; 6.4.6 Release the pilot-controlled butterfly valve at the outlet from the interlock. Shut the butterfly valve; 6.4.7 Check that the butterfly valve at the outlet is closed, shut the circulating water pump and see to it that the pump develops a reversed rotation;
6.5. Operation Monitoring and Adjustment of Circulating Water System 6.5.1 Check the current of the circulating water pump to ensure that it is normal, the oil level in the motor bearing is normal, the oil quality is acceptable and there is no abnormal noise emitting from the pump body; 6.5.2 Monitor the following parameters closely to prevent an exhaust stem temperature rise or vacuum drop in the condenser, attributable to insufficient pump capacity: outlet pressure of the circulating water pump and the inlet/outlet pressure of the circulating water for the condenser; 6.5.3 The temperature difference of circulating water for the inlet and outlet of the condenser must be less less than 8℃ and must must not not excee exceed d the maxim maximum um of of 12℃ ; if the requir requireme ement nt is is not met, met, ident identify ify and correct the cause promptly; 6.5.4 Check that the oil level and pressure of the oil system for the pilot-controlled butterfly valve at the outlet of the circulating water are normal; 6.5.5 Check that the water level in the circulating water collecting sump is normal and the sump pump has normal interlock; otherwise, start and shut down the sump pump manually; 6.5.6 Check that the water levels of the intake chamber, cooling tower, bearing and motor are normal; check that the flow rate in the cooling tower is constant; 6.5.7 Monitor the filth removal unit in the circulating water intake chamber to check that an automatic flush is operable; othe rwise, flush it manually. manually. 7 Open Circulating Cooling Water System
7.1. Pre-Startup System Check 7.1.1 Check that the open pump meets the following startup conditions: 7.1.1.1 Check that the electric valve at the inlet of the pump is open; 7.1.1.2 Check that the electric valve at the outlet of the pump is open; 7.1.1.3 Check that the filter at the outlet of the open water filter is correctly put into operation, or the bypass valve of the open water filter is open; 7.1.1.4 Check that the inlet and outlet valves of the coolers in the open circulating water system is open; 7.1.2 Check that the circulating water system is commissioned and is working normally; 7.1.3 Check that the valves of the open circulating water system are in a good working condition 195
by pushing the valve check card; 7.1.4 Check that the water injection and air discharge process has been finished for the open circulating water system;
7.2. Open Cooling Water System Startup 7.2.1 Check that the open pump has met all startup conditions specified in General Rules for
Auxiliary Equipment Operation ; 7.2.2 Check and confirm that the circulating water system has been satisfactorily commissioned; 7.2.3 Start up an open pump; ensure that the return current is normal and the outlet valve of the pump opens automatically; 7.2.4 Check that the open pump has normal outlet pressure; 7.2.5 Open the vent valves of all coolers; if there is water, shut them; 7.2.6 Open the inlet valve of the standby open pump and commission the interlock; 7.2.7 Commission the coolers to operation as required;
7.3. Open Cooling Water System Shutdown 7.3.1 Check and confirm that all users of the open water pump meet the relevant requirements; 7.3.2 Release the standby pump from the interlock; shut the outlet valve of the open pump and then shut down the pump; 7.3.3 Check that the check valve at the outlet is shut and the pump does not develop a reversed rotation;
7.4. Open Cooling Water System Monitoring and Adjustment 7.4.1Check that the pipes and equipment pertaining to the open circulating water system have no leak; 7.4.2 Check that the following pump parameters are normal: pump current, pump vibration, sound, bearing temperature, outlet pressure and seal gland leak; 7.4.3 Check that the differential pressure on the two sides of the open water filter is normal; 7.4.4 Check that the standby open pump meets the interlock and standby requirements; 7.4.5 Check that the changeover and testing tasks are satisfactorily accomplished; 7.4.6Limits of Operational Parameters of the Open Circulating Water System:
Item
Unit
Outlet Pressure of Open Pump
MPa
Differential Pressure on Two Sides of Open Water Filter
Normal
Upper
Lower
Value
Limit
Limit
MPa
Bearing Temperature of Open Pump
℃
Bearing Temperature of Pump Motor
℃
Pump Current
A
7.5. Open Circulating Water System Accidents Treatment 196
7.5.1 If the open water pump trips in operation, the standby pump must be started up in an interlock mode, otherwise start the standby pump manually; 7.5.2 If all open pumps are shut down and can not be started temporarily, promptly reduce the pump load and cut off water supply to minor users. Open the inlet and outlet valves for the two pumps to ensure uninterrupted cooling water supply to important equipment; 8. Condensate System
8.1. Pre-Startup Check and Preparation 8.1.1 Finish the operations as required by General Rules for Pre-Startup Check of Auxiliary
Equipment and System ; 8.1.2 Check that all valves are in the correct position as indicated by the valve check card before the system starts up; 8.1.3 Confirm that the service water system is operating reliably; 8.1.4 Contact the chemical engineer to start the demineralization pump to supply makeup water to the condensate storage tank. Confirm that the water level in the tank is normal and the water quality is acceptable; 8.1.5 Check that the condensate delivery pump meets the relevant requirements, the inlet valve and the recirculating valve of the pump are open and the outlet valve is closed. Close the drain valve on the steam side of the condenser, start the condensate delivery pump and check that the system is working properly before supplying makeup water to the condenser; 8.1.6 Open the injection valve connecting the condensate delivery pump to the condensate system to inject water. Open the vent valves of the condensate pipe system to discharge the air. The vent valves will close on contact with water; 8.1.7 Open the sealing water valve for the condensate pump to deliver sealing water; 8.1.8 Open the vent valves at the inlet/outlet of the condensate pump and a t the inlet of the strainer. After water makeup and air discharge operations are completed, close the vent valves at the inlet/outlet of valves for the condensate pump and the vent valve for the strainer; 8.1.9 Commission the cooling water for the motor bearing of the condensate pump and check if the backwater is working properly; 8.1.10 Check if the oil level in the bearing of the condensate pump is normal; 8.1.11 Open the air valve for the condensate valve; 8.1.12 When makeup water in the condenser reaches a normal level, close the makeup water bypass valve; 8.1.13 Open the front and rear cut-off valve of the makeup water control valve for the condenser and commission automatic control for the water level.
8.2. Condensate System Startup 8.2.1 Startup of Condensate Pump 8.2.1.1 Check and confirm that the condenser water level is normal, the cooling water supply to 197
the condensate pump and the motor is normal and all interlock protection tests have been passed; 8.2.1.2 Check and confirm that the inlet water valve of the condensate pump and the condensate recirculating valve are open; 8.2.1.3Start one of the condensate pumps and observe the starting current and the current return time. Check that the outlet water valve is automatically and promptly opened. Check that the following parameters of the pump are normal: pump vibration, sound, bearing & motor coil temperature, motor current, outlet pressure, differential pressure on two sides of the strainer, sealing water pressure and condenser water level. Check that the system has no leak; 8.2.1.4 Contact the chemical engineer to test the quality of the condensate water. If the quality is unacceptable, the condensate water must not be delivered to the deaerator. Close the outlet valve for #5 low pressure heater and open the drain valve on the water outlet pipe to replace water. Condensate water must not be delivered to the deaerator unless the quality is acceptable; 8.2.1.5 Commission the condensate polisher as required by the system; 8.2.1.6 Check that the condensate recirculating valve is automatically closed as the flow rate of condensate increases; 8.2.1.7 Commission the users of the reclaimed condensate as required. 8.2.2 Commissioning of another Condensate Pump on Standby 8.2.2.1 Check and confirm that the drain valves at the pump inlet/outlet and the vent valve of the pump are closed; 8.2.2.2 Commission the sealing water for the standby condensate pump; 8.2.2.3 Open the evacuation valve at the inlet of the pump. If the condenser is in a vacuum state, open the valve slowly and monitor the condenser vacuum and the operation of the working pump; 8.2.2.4 Open the inlet valve of the condensate pump to inject water. Monitor the vacuum change of the condenser; 8.2.2.5 Check that the condensate flow rate and the manifold pressure are normal. Open the outlet valve of the standby pump and see to it that the pump rotation must not be reversed. Check that the standby condensate pump meets the standby requirements before commissioning the interlock for the pump.
8.3. System Shutdown 8.3.1 Confirm that the vacuum system is shut down after the unit is shut down, the exhaust steam temperature temperature of the the low-press low-pressure ure cylinder cylinder is is lower than 50℃ and the users users of the the condensate condensate system approves a system shutdown or have switched to the standby water supply; 8.3.2 Check and confirm that the de aerator has stopped water intake and all the condensate users have shut down the system and met the shutdown requirements; 8.3.3 Contact the chemical engineer to decommission the condensate polisher; 8.3.4 Switch the standby pump to the manual mode and shut the outlet valve; 8.3.5 Shut down the condensate pump and shut all outlet valves via the interlock. Ensure that the pump current drops to zero and the pump develops no reverse rotation. 198
8.4. System Operation and Maintenance 8.4.1 Monitor the water levels in the condensate storage tank and the condenser hot well to check that they are normal. Check that the automatic control for water makeup is normal. In case that the automatic control fails for the water level or in the case of an emergency, manual operation is allowed; 8.4.2 Check that the following parameters of the condensate pump are normal: outlet pressure, flow rate, current, coil temperature and bearing temperature. Conduct a site inspection to ensure that the condensate pump has normal sound and vibration; 8.4.3 Check if the standby pump is in a sound standby condition; 8.4.4 Changeover of Condensate Pump: 8.4.4.1 Check that the standby pump is in a sound standby condition and is ready to be commissioned reliably; 8.4.4.2 Check that the sealing water has been correctly commissioned for the standby condensate pump; 8.4.4.3 Confirm that the inlet valve of the standby condensate pump is open; 8.4.4.4 Confirm that the outlet valve of the standby pump is closed; 8.4.4.5 Check that the condensate water system is working reliably; 8.4.4.6 Confirm that the evacuation valve at the inlet of the standby pump is open; 8.4.4.7 Release the standby condensate pump from the standby mode; 8.4.4.8 Start the standby pump and monitor the opening process of the interlocked electric valve at the outlet; 8.4.4.9 Check that the following parameters are normal after the standby pump is started: motor current, vibration, sound, etc. Check that the LCD indicator lamp has correct indication; 8.4.4.10 Stop the working pump and check that the current drops to zero. Check that the check valve at the outlet is closed and the electric valve at the outlet is closed by the interlock; 8.4.4.11 Check that the manifold at the pump outlet has emitted no “low pressure” signals. Commission the original pump in standby mode as requ ired;
8.5 System Accidents Treatment 8.5.1 Trip of Condensate Pump 8.5.1.1 Symptoms 1) The CRT sounds an alarm and the current drops to zero; 2) The flow rate of the condensate manifold drops sharply and the outlet pressure drops slightly; 3) The water level in the condenser hot well rises and the level in the deaerator drop; 8.5.2.2 Treatment 1) First confirm that the standby pump is automatically started, otherwise start it manually; 2) Adjust the water level in the condenser and the deaerator to normal; 3) If the standby pump is not successfully started, force a startup attempt on the tripped pump. If the attempt is unsuccessful, consider a reduction of the present load; 199
4) Identify the cause of tripping. 8.5.3 Idling Condensate Pump 8.5.3.1 Symptoms 1) The current drops and fluctuates; 2) The outlet pressure and the condensate flow rate of the pump drop; 3) When two condensate pumps are operating, one pump develops a rise in flow rate. 8.5.3.2 Treatment 1) Arrive promptly on the site to locate any abnormal noise; 2) Shut down the faulty pump and manually start up the standby pump; 3) Adjust the water levels of the condenser and the deaerator to normal; 4) Identify the cause of the idling pump; 9. Regeneration and extraction Steam System 9.1. Pre-Startup Check and Operation 9.1.1 Pre-Startup Check and Preparation of Deaerator 9.1.1.1 Complete the operations as required by General Rules for Pre-Startup Check of Auxiliary
Equipment and System ; 9.1.1.2 Push the system check card to ensure that the valves are in the correction position; 9.1.1.3 Check that all the following valves are in a proper working condition: deaerator startup vent valves, continuous vent valves, all isolating valves connecting deaerator overflow valves to condenser pipes and all bypass valves connecting the overflow valves to the condenser; 9.1.1.4 Check and confirm that the deaerator startup vent valvex is open and the normal vent valve is closed; 9.1.1.5 Confirm that the auxiliary steam system has been commissioned, the condensate system has been adequately filled and the water quality is acceptable; 9.1.1.6 Confirm that all control air supply has been properly commissioned for the system, the power supply for the electric valves is commissioned and the valves are in a correctly position; 9.1.1.7 The pre-startup check and preparation work must precedes the same work for the high/low pressure heaters, so that auxiliary steam-heated feed water may be supplied once the conditions are met; 9.1.1.8 Check that deaerator has passed the water level test and the pressure interlock protection test. Commission water level & pressure metering devices and protection devices for the deaerator; 9.1.1.9 Confirm that the auxiliary system is operating normally and the auxiliary steam pressure and temperature meet the requirements; 9.1.1.10 Confirm that the condensate delivery pump is working stably and the water quality is acceptable; 9.1.2 Heater Commissioning & Decommissioning 200
9.1.2.1 While the unit is in operation, if #7 and #8 low-pressure heaters develop a leak which actuates the water level protection mechanism, reduce the load to 540MW (in the event of a rated unit load), open the bypass valves on the water side of the two heaters and close the electric valves for inlet/outlet water; 9.1.2.2 If the unit is operating in a rated load condition, decommission all four low-pressure heaters to reduce the unit load to 70%, decommission three low-pressure heaters to reduce the unit load to 80%, or decommission two low-pressure heaters to reduce the unit load to 90%. If all high-pressure heaters are decommissioned, the rest of the unit parameters can support a unit load of 100%; 9.1.2.3 If the high/medium pressure cylinders are simultaneously started, the heater generally has a random startup in response to the rolling of the unit. If the medium pressure cylinder is used to start up the high-pressure cylinder, the heater will be commissioned after a cylinder changeover. Commission the low-pressure heaters before the high-pressure heaters, and the water side before the steam side. Decommission the high-pressure heaters before the low-pressure heaters, and the steam side before the water side. Ensure that the rate of temperature rise/drop is less than 2℃/min; 9.1.2.4 The heater must not be started in case any of the following faults occurs: 1）The heater protection & interlock fails; 2）Check that the safety valves on the steam/water side of the heater have a malfunction; 3）he steel pipe of the heater develops a leak; 4）The main supervisory instruments of the heater have a fault; 5）The check valves of the different extraction steam sections have a failure; 6）The major steam/water delivery valves and steam trap valves have a control failure; fa ilure; 7）The heater has any other defect that seriously affects a safe operation; 8）The high pressure heater is commissioned before the low-pressure heater (the reverse is correct). 9.1.3 Pre-Startup Check and Preparation of Low-Pressure Heater 9.1.3.1 Complete the operations as specified by General Rules for Pre-Startup Check of Auxiliary
Equipment and System ; 9.1.3.2 Confirm that the heater and pipes are acceptably flushed; 9.1.3.3 Confirm that the water quality of the condensate system is acceptable; 9.1.3.4 Confirm that the compressed air system is functioning reliably; 9.1.3.5 As required by the check card for low-pressure heater commissioning system, adjust the valves to the required position and confirm that the steam trap valves are working properly and the automatic control mechanism has been actuated; 9.1.3.6 Check that the local water level gauge for the low-pressure heater is sound and working properly; 9.1.3.7 Contact the heat engineer for commissioning of the water level protection for low-pressure 201
heaters; 9.1.4 Pre-Startup Check and Preparation of High-Pressure Heater 9.1.4.1 Confirm that the overhaul work is completed, the worksheets are completed and the equipment is complete and sound; 9.1.4.2 Confirm that the heater and the pipes are acceptably flushed; 9.1.4.3 Confirm that the water temperature of the deaerator feed water tank is normal and the water levels of all high-pressure heaters are normal; 9.1.4.4 Contact the heat engineer for required power supply to meters, instruments and signal lamps. Contact the electrical engineer for required power supply to electric valves. Ensure that the equipment has smooth and flexible operation. 9.1.4.5 Confirm that the compressed air system is working properly; 9.1.4.6 As required by the valve check card, adjust the valves to the required position and commission the water level gauges as required; 9.1.4.7 Confirm that all steam trap valves are working properly and the automatic control mechanism has been actuated; 9.1.4.8 Confirm that all protection and automatic mechanism tests are passed and the protection mechanism for all heaters is commissioned;
9.2. System Startup 9.2.1 Deaerator Startup 9.2.1.1 Refill the deaerator to the starting water level with the condensate delivery pump or condensate pump; 9.2.1.2 Open the steam trap valve between the auxiliary steam and the deaerator heat pipe to effect a drainage; confirm that the circulating water has been properly commissioned for the condenser; 9.2.1.3 Commission the auxiliary steam for the heating process, open the front and rear isolating valves between the auxiliary steam and the deaerator, slowly open the pressure control valve between the auxiliary steam and the deaerator and maintain the rate of temperature rise of the feed feed water water for the deaerat deaerator or belo below w 1.5 1.5℃ /min; /min; 9.2.1.4 After the the water tempera temperature ture of the deaerator deaerator reaches reaches 100 100℃ , open the electric electrical al continuous continuous vent valve, close the pressure control valve between auxiliary steam and commission the deaerator deaerator in the the automatic automatic mode. mode. Check Check that the the rate of temperature temperature rise rise is lower lower than than 1.5℃ /min. When the pressure rises to 0.15MPa, the deaerator works under a constant pressure; 9.2.1.5 The deaerator water level may be controlled by opening the electric valve between the discharge outlet and the drain flash tank. Hot-flush the deaerator as required; 9.2.1.6 After the condensate pump is started, commission the loop between the overflow valve of the deaerator to the drain flash tank of the condenser to operation. The automatic mechanism must be actuated for the deaerator water level control; 9.2.1.7 If the condensate water quality is acceptable, switch the condensate water to the dea erator. 202
Commission the deaerator water level in the automatic mode and check that the deaerator a nd the condenser have a normal water level; th
9.2.1.8 When the 4 extraction reaches a pressure of 0.15MPa, check that the pressure and water level of the deaerator are normal; open the electric valve between the 4th extraction and the th
deaerator. For the deaerator, the auxiliary steam will switch to the 4 extraction and the pressure control valve between the auxiliary steam and the deaerator will be closed. Check that all steam trap valves for the 4th extraction pipes are closed and the deaerator switches from constant pressure operation to sliding pressure operation; 9. Ensure that the water inflow speed is so controlled that the deaerator will maintain constant temperature and pressure; 9.2.1.10 While the deaerator is in sliding pressure operation, open the isolating valve between the continuous drain valve of the boiler and the deaerator, depending on valve condition and water quality; 9.2.2 Startup of Low-Pressure Heater 9.2.2.1 Commissioning of Water Side 1) Commission the condensate pump, open the water inlet valves of the low-pressure heaters to inject water into #8 heater through to #5 heater. If the vent valve o n the water side is in contact with water, check that the water level of the gauge for the low-pressure heater does not change in times of water injection and the condensate flow rate doesn’t change on completion of water injection; 2) Check that the inlet and outlet valves on the water side of the low-pressure heater are fully open; 3) Flush the low-pressure heater as requ ired for an acceptable quality; 9.2.2.2 Commissioning of Steam Side 1) Commission the steam side of #7A/#7B and #8A/#8B low-pressure heaters in the random mode while the turbine is rolling; 2) After a vacuum is created for the turbine, shut down #6/#5 heaters in turn and start the vent valve for the low-pressure heater slowly. Observe the vacuum changes in the condenser. If there is a major change, shut the valve quickly and identify the leak. Correct the leak before starting the continuous air vent process; 3) After the turbine rolls, commission #6/#5 heaters for the steam side and check that the steam trap valves of the extraction pipes are open. If the extraction check valve of the low-pressure heater is in a free state, open the electric valve slightly for a pre heating. Control the rate of outlet temperature temperature change change of the the low-press low-pressure ure heater heater below 3℃ /min. Then Then open the the electric electric valve valve fully and the normal drainage control valve must be working properly; 4) When check valves of the 5th and 6th extraction sections are open, check that all steam trap valves of the 5th and 6th extraction pipes are closed. 9.2.2.3 Commissioning of Low-Pressure Heater during Unit Operation 203
1) Ensure that all the overhaul work has been completed, the worksheets have been recalled and the site has been cleaned. There is no object that may pose a hindrance to system startup; 2) Ensure that all pre-startup checks and operations are completed; 3) Inject adequate water supply and exhaust the air when the water side is commissioned. During the injection, monitor the water level in the drain valve closely to ensure there is no change; when condensate water is switched from the bypass to the main loop, monitor the condensate flow rate in case of a cutoff in water supply; 4) Open the continuous vent valve of the low-pressure heater slowly and monitor the condenser vacuum closely in case of a rapid drop in vacuum. If there is a rapid drop in vacuum, shut the valve immediately, check the heater and confirm the correction of the leak before further operations are allowed; 5) When the steam side is commissioned, ensure that the pipes have been adequately heated. Control the rate of temperature rise on the outlet water side of the commissioned heater below 3℃/min; 6) After the extraction check valve is open, check that all steam trap valves of the extraction steam pipes are closed; 9.2.3 Commissioning of High-Pressure Heater 9.2.3.1 Commissioning of the Water Side 1) Check that the feed pump is operating reliably and the electric valve at the outlet has been opened; 2) Contact the heat engineer for the commissioning of water level protection for the high-pressure heater; 3）Slightly open the electric water injection valve at the outlet of the high-pressure heater to carry out a water side leak test by water injection. When water overflows from the vent valves on the water side of #1, #2 and #3 high-pressure heaters, observe the water level change at the steam side; 4） After the internal water pressure of the high-pressure heater reaches to the full value, slowly open the electric outlet valve of the heater and switch the bypass to the inlet side of the heater. Observe the flow rate and pressure changes of the feed water. 9.2.3.2 Commissioning of Steam Side 1) Confirm that the water side of the high-pressure heater has been commissioned, the water-level interlock protection test on the high-pressure heater has been passed and the condenser vacuum is normal; 2) Ensure that the system has switched to the high-pressure cylinder of the turbine. When the unit load reaches 30% of the rated load, commission the steam side of the high-pressure heaters (sequence: #3, #2 and #1) 3) Check that all related steam trap valves of the extraction steam pipe have been open. If the extraction check valve of the high-pressure heater is in a free state, open the electric valve for 204
the extraction steam slightly to preheat the heater. Control the rate of outlet temperature change of the the lowlow-pres pressur sure e heater heater below below 3℃ /min.; /min.; 4) After steam is admitted into the high-pressure heater, close the startup vent valve and open the continuous vent valve on the steam side; 5) After the preheating, slightly open the steam extraction electric valve for the high-pressure heater and check that the normal drainage control valve functions reliably; 6) ；When the check valves for the 3rd, 2nd and 1st steam extractions are opened, check that all steam trap valves for the extraction steam pipes are closed; 7) While the high-pressure heater is being commissioned, try to maintain the load balance of the unit and check that the water level automatic control for the heater is normal; 8）When the steam side pressure of #3 high-pressure heater exceeds 0.2MPa, deliver the drainage from the heater into the deaerator and monitor and control the pressure and water level of the deaerator. 9.2.3.3 Commissioning of High-Pressure Heater during Unit Operation 1） After the feed water system is commissioned, commission the water-side of the high pressure heater as required by the relevant operation codes; 2）Check that the water side of the heater has no leak, high water level alarm is not available for the steam side and alarm signals for the heater parameters are working properly; 3）Contact the relevant staff to commission water level protection fo r the heater; 4）Check the valve status prior to the startup of the heater. Open the continuous vent valves on the steam side and close the startup vent valves on the steam side; 5）In the event of a simultaneous startup of high/medium pressure cylinders (the medium pressure cylinder starts up after the cylinder transfer), open the check valves and electric valves for the 1st, 2 nd and 3rd steam extractions. The steam pressure in the heater will rise as the load increases; 6）When the unit load exceeds 20%, confirm that the steam trap valves behind the extraction steam check valves and the drain valves in front of the extraction steam electric valves are closed. When the pressure on the steam side of #3 high pressure heater exceeds 0.2MPa, deliver the drainage from #3 high-pressure heater into the deaerator and monitor and control the pressure and water level of the deaerator; 7） After the drainage from the high-pressure heater is adjusted to normal in the downgrade flow mode, commission the automatic mechanism for the water level in the high-pressure heater and check that the automatic adjustment of the water level is normal; 8）The pipe must be heated adequately before the steam side of the high-pressure heater is commissione commissioned. d. Maintain Maintain the rate rate of temperatu temperature re rise at the the outlet outlet of the heater heater below 3℃ /min. In In the commissioning process, monitor the variation of the following parameters: unit load, axial displacement and differential expansion.
9.3. System Shutdown 205
9.3.1 Shutdown of Low-Pressure Heater 9.3.1.1 Shut down of Steam Side of Low-Pressure Heater 1) Allow #5, 6, 7A/B and 8A/B low-pressure hea ters to shut down in the random sliding mode; 2) Confirm that the electric valve and the check valve for steam extraction are automatically shut and all steam trap valves for the steam extraction pipe are automatically open; 3）Close #1 and #2 continuous vent valves between the low-pressure heater and the condenser; 9.3.1.2 Shutdown of Water Side 1) Before the water side of the low-pressure heater is shut down, open the bypass valve before closing the other inlet and outlet valves. Monitor the change of the condensate flow rate; 2) If the heater is to be disused for a long time, drain it out and charge it with nitrogen fo r storage and maintenance; 9.3.1.3 Shutdown of #5 and #6 Low-Pressure Heaters during Unit Operation 1) Reduce the turbine load to a specified value, depending on the shutdown condition of low-pressure heaters; 2）Release the automatic mechanism for the water level of #5 low-pressure heater, open the emergency steam trap valve between #5 heater and the condenser and close the drainage control valve and isolating valve between #5 heater and #6 heater; 3）Release the automatic mechanism for the water level of #6 low-pressure heater, open the emergency steam trap valve between #6 heater and the condenser and close the drainage control valve and isolating valve between #6 heater and #7 heater; 4）Close the electric steam inlet valve for #6 low-pressure heater and close the check valves for the 6th steam extraction. Ensure that the drain valves in front of the electric valve and behind the check valve are open; 5）Close the continuous vent valve between #6 low-pressure heater and the condenser; 6）Close the drain valve behind the check valves for the 6th steam extraction; 7）Close the emergency drainage control valves and the front and rear isolating valves for #6 low-pressure heater. Open the drain valve for pipes in front of the emergency drainage control valve of #6 low pressure heater; confirm that the isolating valve in front of the emergency drainage control valve is tightly closed; 8）Check that steam side pressure of #6 h eater drops to zero. Open the start-up vent valve of #6 heater to observe the air discharge conditions and confirm that the electric valve, check valve and emergency drain valve are tightly closed. Open the drain valve on the steam side of #6 heater to drain it out; 9）Open the electric bypass valve on the water side of #6 heater and slowly close inlet/outlet valves of #6 heater. Monitor the flow rate of condensate to ensure a steady flow; 10）Confirm that the inlet/outlet valves of #6 low-pressure heater are closed. Open the drain valve on the water side of the heater to monitor and ensure a steady flow rate of condensate water; 206
11）Carry out other isolation steps for the overhaul work. Follow the above steps in the shut down process of #5 low-pressure heater. 9.3.1.4 Shutdown of #7 and #8 Low-Pressure Heaters during Unit Operation 1) Reduce the turbine load to a specified value, depending on the shutdown condition of low-pressure heaters 2） Release the automatic mechanism for the water level of #6 low-pressure heater, open the emergency steam trap valve between #6 heater and the condenser and close the drainage control valve and isolating valve between #6 heater and #7 heater; 3）Open the bypass valves for the water side of #7 and #heaters and gradually shut the inlet valves of #8 heater (#8A and #8B). Monitor the change of condensate flow rate; 4）Open the emergency drainage control valve for #8A or #8B low-pressure heater; 5) Before opening the drain valves and vent valves, close the normal manual steam trap valve, manual emergency steam trap valve, continuous vent valve and normal manual steam trap valve between the upstream heater and the low-pressure heater; 6) Carry out other isolation steps for the overhaul work. 9.3.2 Shutdown of High-Pressure Heater 9.3.2.1 Shutdown of Steam Side 1) When the load drops to 30% of the rated load, slowly turn off the steam extraction electric valves in turn of (#1, #2 and #3); 2) When the extraction steam check valve is auto matically shut, all the steam trap valves for the extraction pipe must open automatically; 3) Close the manual isolating valve between the continuous vent valve of the high-pressure heater to the deaerator; 4）Observe the change in temperature difference and load of the upper/lower cylinders. 9.3.2.2 Shutdown of Water Side 1) After the heater is shut down, decommission the water side a s required; 2）Switch the water side of the high-pressure heater to the bypass, close th e electric valve at the outlet side of the heater and watch closely the change in feed water flow rate; 3) If the heater is to be disused for a long time, drain it out and charge it with nitrogen fo r storage and maintenance. 9.3.2.3 Shutdown of High-Pressure Heater during Unit Operation 1) Before shutting down the high-pressure heater, reduce the turbine load to a specified value; 2) Shut the continuous vent valves for the heater; 3) Slowly close the steam extraction electric valve and check that the change in turbine differential expansion and axial displacement is within the controllable range. Ensure that the temper temperatur ature e drop drop of outl outlet et water water is belo below w 3℃ /min; /min; 4) After the steam side is decommissioned, switch the water side of the high-pressure heater to the bypass, close the electric valve at the outlet side of the heater and watch closely the change 207
in feed water flow rate; 5) Before opening the drain valves and the vent valves, shut all manual emergency drainage valves and isolating valves between the high-pressure heater and the condenser; 6) Carry out other isolating steps of the overhaul work; 9.3.2.4 Random Sliding Shutdown of High-Pressure Heater 1 ） Under normal shutdown condition, adopt a random sliding shutdown mode for the high-pressure heater; 2） After the turbine trips, check that the feed steam steam check valves and the electric valves are shut through interlock. Check that the normal drainage valve is closed and the emergency steam trap valve is opened through interlock; 3）Shut the primary and secondary continuous vent valves between the high-pressure heater and the deaerator. 9.3.3 Deaerator Shutdown 9.3.3.1 When the unit load reaches 20% of the rated load, check that the steam trap valves for the 4th extraction pipes are automatically opened; th
9.3.3.2 When the pressure of the 4 extraction drops below 0.15MPa, the steam supply to the deaerator switches from the 4th extraction to the auxiliary steam. Close the isolating valve th
connecting the 4 extraction to the deaerator, open the pressure control valve between auxiliary steam and deaeratorand maintain the deaerator pressure at a constant value of 0.15MPa; 9.3.3.3 After the continuous drain valve is shut down, close the isolating valve connecting the continuous drain valve to the deaerator; 9.3.3.4 After feed water supply to the boiler is cut off, switch the heating control valve between the auxiliary steam and the deaerator to the manual mode before shutting it. Close the heating isolating heater valve between the auxiliary steam and the deaerator; 9.3.3.5 ； After the feed pump is shut down, switch the deaerator water level adjustment to the manual mode and shut it; 9.3.3.6 If the deaerator is to be disused for over one week, adopt nitrogen blanketing protection, cut all steam supply and water supply and drain out the water tank. Shut the drain valve. After the deaerator is fully isolated, start the master nitrogen charging valve and the isolating valve. While charging the deaerator with nitrogen, maintain constant pressure.
9.4. System Maintenance 9.4.1 Operating Monitoring and Adjustment of High/Low-Pressure Heater 9.4.1.1 Patrol the steam extraction pipes of the heater on a regular basis. Check that the drain pipes have no leak and vibration; 9.4.1.2 An abrupt change of load may cause a change of the heater’s water level. Adjust the water level promptly; 9.4.1.3 Avoid prolonged heater operation at zero (low or high) water level; 9.4.1.4 Monitor the following parameters of the heater, including but not limited to temperature of 208
steam extractions, pressure, feed water temperature rise, terminal temperature difference and water level; adjust the terminal temperature difference within a tolerable, feasible and economically viable range; 9.4.1.5 Under rated working conditions, the pressure, temperature and extraction capacity of the steam extractions must be constant. In the event of a deviation from the design value, analyze the cause. 9.4.2 Operation Monitoring and Adjustment of Deaerator 9.4.2.1 Ensure that the deaerator operates in the fixed-sliding-fixed mode. The deaerator’s range of sliding pressure is between 0.15-1.05MPa. When the unit load varies, monitor the pressure and temperature of the deaerator to ensure that they conform to the local conditions; 9.4.2.2 ；Check that the water level automatic adjustment is sound for the deaerator and the adjusted water level displayed on the CRT; CRT; 9.4.2.3 Adjust the opening of the normal vent valve according to the feed water oxygen content. Ensure that the deae rator works in accordance with economical requirements; 9.4.2.4 Check that the deaerator has no vibration and the deaerator and the system have no leak; 9.4.2.5 Check that the heating control valve between the auxiliary steam and the deaerator are commissioned in the automatic mode. Heat the pipe in front of the control valve properly; 9.4.2.6 If the deaerator is heated by auxiliary steam, maintain the deaerator pressure under a constant pressure of 0.15MPa. The deaerator must not be overloaded in operation.
9.5. Accidents Treatment Treatment 9.5.1 An emergency shutdown of the low-pressure heater must be enforced in any of the fo llowing cases: 9.5.1.1 When the steam/water pipes and valves of the heater burst and endangers personal safety and the safety of equipment; 9.5.1.2 When the heater water level rises, a solution is not effective or the low-pressure heater is filled with water; 9.5.1.3 When all water level indications fails and the water level fails to effectively monitored; 9.5.1.4 When the extraction check valve jams; 9.5.1.5 When the heater works under overpressure and the safety valve fails to work; 9.5.2 Water Level Rise of Low-Pressure Heater 9.5.2.1 Causes: 1) The water side has a leak or burst; 2) The steam trap valve fails; 3) The water level transducer fails; 9.5.2.2 Treatment: Decommission the steam/water side of the heater. 9.5.3 Deaerator Vibration 9.5.3.1 Causes: 1) The water inflow into the deae rator increases or decreases sharply; 209
2) The steam inflow into deaerator increases or decreases sharply; 3) The abrupt rise or fall of feed water causes rapid fluctuation of the deaerator water level; 4) The deaerator has a leak; 5) A great quantity of drainage from the high-pressure heater abruptly penetrates into the aerator; 9.5.3.2 Treatment 1) Adjust the water inflow into a deaerator; 2) Adjust the steam inflow into a deaerator; 3) Adjust the flow rate of feed wate r; 4) Adjust the water level of the deaerator; 5) Adjust the drainage and draining type of the high-pressure heater. 9.5.4 Increase of Deaerator Oxygen Content 9.5.4.1 Causes 1) Insufficient dosage or dosing interruption of hydrazine of hydrazine;; 2) Insufficient supply or interrupted supply of steam inflow; 3) Abrupt rise of deaerator pressure; 4) Vent pipe blockage; 5) Serious blockage or detachment of nozzles in the deaeration piece; 9.5.4.2 Treatment 1) Adjust the hydrazine dosage; 2) Increase steam inflow or switch to other steam supply; 3) Maintain a constant load; 4) Enforce a shutdown or take corresponding steps before a solution is implemented. 9.5.5 Abrupt Drop of Deaerator Pressure 9.5.5.1 Causes 1) Interrupted steam inflow; 2) Infiltration of large quantities of condensate water as a result a malfunctioning water level control valve of the deaerator; 3) The steam trap valve and safety valve of the deaerator are open by mistake; 9.5.5.2 Treatment: Identify the cause of the pressure drop of the deaerator and take corresponding steps. 9.5.6 Abrupt Rise of Deaerator Pressure 9.5.6.1 Causes 1) The condensate pump trips, or the water level control valve fails, causing a cut of water inflow; 2) The unit is overloaded. 9.5.6.2 Treatment 1) Restore the water inflow for the deaerator promptly; 210
2) Reduce the load to normal. 9.5.7 The high-pressure heater must be shutdown in an emergency state in the following cases; 9.5.7.1 When there is a burst of steam/water pipes and valves, which endangers personal safety and equipment safety; 9.5.7.2 When the heater water level rises, a solution is not effective or the low-pressure heater is filled with water; 9.5.7.3 When all water level indicates fail and the water levels fait to be monitored; 9.5.7.4 When the extraction check valve jams; 9.5.7.5 When the heater works under overpressure and the safety valve fails. 9.5.8 Rise of Water Level 9.5.8.1 Causes 1) The water level transducer fails; 2) The drainage control valve fails; 3) The water side has a leak or burst. 9.5.8.2 Treatment 1) Calibrate the water level transducer; 2) Check the drainage control valve; 3) De-commission the steam side and water side of the heater. 10. Feed pump System 10.1.1 Pre-Startup Check of Electric Pump 10.1.1.1 Check that the deaerator water level is normal and the condensate water system has been properly commissioned; 10.1.1.2 Check that the scoop tube controller is in the manual position and manual operation is smooth and has no jam or skip. Check that the rotational direction is correct and the controller is adjusted to the lower limit; 10.1.1.3 Check that all interlock protection tests of the electric pump have been passed; Commission all interlock protection mechanism and the meters and instruments; 10.1.1.4 Confirm that the open circulating water and service water have been correctly commissioned. Commission the mechanical seal cooling water for the booster pump and the electric feed pump. Commission the service oil and cooling water for the lube oil cooler as required by the oil temperature. Check that the oil level in the pump oil tank is normal and the oil system meets all preconditions of commissioning; 10.1.1.5 Check that the pump and drain valves for the pipes are shut; 10.1.1.6 Check that the water level in the deaerator tank is normal, the water quality is acceptable and the water temperature meets the boiler filling requirements. Open the electric inlet valve for the booster pump slightly and inject water into the booster pump, feed pump and pipes to displace the air. The air valve will shut on contact with water. On completion of the water filling and air 211
displacement, open the electric inlet valve fully for the booster pump; 10.1.1.7 Check that the coupler has normal oil level and acceptable oil quality; 10.1.1.8 Check that one unit of lube oil strainers are commissioned and the other unit of strainers are on standby; 10.1.1.9 Check that the fore and rear electric valves for the recirculation control valve are open for the electric pump and the recirculating valve is commissioned in the automatic mode; 10.1.2 Pre-Startup Check of Steam Pump 10.1.2.1 The small steam turbine must not be started in the fo llowing cases: 1) The emergency cutoff device, solenoid valve, overspeed protector, lube oil low pressure protector or low vacuum protector does not function normally; 2) The main steam valve or the steam control valve fails to shut tightly o r work properly; 3) The speed control system fails to operate stably or the rotating speed fails to be controlled; 4) The main instruments and meters fail to monitor the following parameters properly: feed steam pressure & temperature, vacuum, rotating speed , operating oil pressure, lube o il pressure, etc.; 5) The main operating oil pump, DC oil pump or turning gear fails to function properly; 6) The turning gear emits abrasion noise from the interior; 7) The oil quality is unacceptable or the oil level is low. 10.1.2.2 Check that all meters & instruments, automatic mechanism and heat protection have been correctly commissioned; 10.1.2.3 Push the pre-startup check card to check that the small steam turbine meets pre-startup requirements; 10.1.2.4 Check that the rotating speed of the steam pump is in the manual mode, the manual trip lever is in the trip position, and the main steam valve, steam control valve and steam vent butterfly valve are closed; 10.1.2.5 heck that the EH oil system of the main steam turbine has been correctly commissioned; 10.1.2.6 Commission cooling water for the booster pump; 10.1.2.7 Check that cooling water for the mechanic seal has been commissioned for the steam pump; 10.1.2.8 Carry out opening/shutting tests on the steam vent butterfly valve for the small steam turbine before vacuum is created for the main steam turbine. Check that the steam vent valve doesn’t jam and shuts tightly.
10.2. Startup of Feed pump 10.2.1 Electric Pump Startup 10.2.1.1 Start up the auxiliary oil pump to check that the following parameters of the pump are normal: pump vibration, sound, temperature, bearing return oil, oil tank level, etc. Check that the lube oil pressure exceeds or is equal to 0.15MPa; 10.2.1.2 Confirm that the recicurlating valve is fully open and has been commissioned in the 212
automatic mode for the pump. Start the pump; 10.2.1.3 After the motor is started, check it that the following parameters are normal: starting current, current return time, rotating speed, pump vibration, bearing temperature, interior noise, inlet/outlet pressure and minimum flow rate; 10.2.1.4 When the lube oil pressure reaches 0.3MPa, the auxiliary oil pump will be automatically shut down; 10.2.1.5 Gradually step up the pump rotating speed to the speed required by the system. Commission the rotating speed control mechanism; 10.2.1.6 Check and confirm that the electric pump is working properly. When the pump outlet pressure is slightly greater than the manifold pressure, open the outlet valve of the pump and commission the automatic mechanism for the feed water (CAUTION: The outlet valve must not be fully opened when the feed water manifold at the outlet has zero pressure. Rather, the outlet valve must be used to control the inflow into the manifold and must not be fully open until the pressurization for the manifold is completed). 10.2.1.7 Open the midpoint tap valve for the electric pump a s per boiler requirements; 10.2.1.8 When switching between an electric pump and a steam pump, check that the flow rate of the two pump types matches; 10. When the electric pump experiences a fluctuation of feed water flow rate, check that the minimum flow valve has a properly working automatic mechanism. When the flow rate drops below 200t/h, the valve must automatically open; when the flow rate exceeds 400t/h, the valve must automatically shut down. 10.2.2 Steam Pump Startup 10.2.2.1 Start the main oil pump and the smoke exhaust fan for the small steam turbine and check that the following parameters are normal: vibration, sound, temperature, bearing return oil and oil tank level. There must be no oil leak in the oil system. Check that the lube oil pressure is maintained maintained around around 0.25MPa 0.25MPa,, the oil oil temperat temperature ure is maintained maintained above 35 35℃ and the interlock for the oil pump has passed the test; 10.2.2.2 Check that the service water has normal pressure. Feed cooling water to the oil cooler, booster pump and the main pump bearing, open the front and rear isolating valve for the attemperating water control valve of the seal gland steam, feed sealing water to the steam pump and open the unloading valve; 10.2.2.3 Confirm that all drain valves in the system are shut and open the electric inlet valve for the booster pump slightly. Open the vent valve, discharge the air and close the valve. Open the electric inlet valve fully for the boo ster pump; 10.2.2.4 Commission the turning gear 2 hours before the small steam turbine rolls. Check that the turning gear rotates at around 100rpm and the interior of the unit and the pump has no noise; 10.2.2.5 10.2.2.5 If the temperature temperature of of the inner inner wall wall of the cylinder cylinder flange flange is below below 100 100℃ , the unit unit is considered considered as being being in the the cold state; state; if the the temperatur temperature e exceeds 100℃ , the unit unit is considere considered d as 213
being in the heated state; 10.2.2.6 Use the electric pump to boost the main steam turbine load to 200MW and the 4
th
extraction pressure to 0.25MPa and above. Only after that may the first steam pump be started (high-pressure steam supply may also be selected accordingly); 10.2.2.7 Commission seal gland steam and check that the seal gland steam pressure is normal; 10.2.2.8 Vacuum-pumping may be synchronized with the main steam turbine or be operated prior to the startup of the small steam turbine: 1) Pump for vacuum before the small steam turbine starts up. First, open the bypass for the steam vent butterfly valve slightly and the vacuum for the small steam turbine will gradually step up. Observe the vacuum for the main steam turbine to check that it doesn’t drop substantially; 2) When the small steam turbine vacuum approaches the main steam turbine vacuum, open the steam vent valve; 10.2.2.9 Commission the automatic mechanism for the steam trap valve for the small steam turbine. Open the steam trap valves for the high/low pressure steam supply pipes, high/low pressure main steam valves and control valves to provide drainage for the small steam turbine and the steam supply system; 10.2.2.10 Check that the minimum flow recirculating valve is open for the steam pump. Start the booster pump for the steam pump. After the motor starts up, check that the following parameters are normal: starting current, current return time, pump vibration, bearing temperature, pu mp noise, inlet/outlet pressure and minimum flow; 10.2.2.11 Check that the small steam turbine meets all rolling conditions: 1) Vacuum: Vacuum: absolute pressure is lower than 21KPa; 2) Resistance to fuel oil pressure is n ormal; 3) Lube oil pressure: 0.25MPa; o il temperature: Above 35℃ 4) Safety oil pressure: Normal; 5) Steam Steam pressu pressure: re: Norm Normal; al; stea steam m overh overheat: eat: 50℃ ; 6) The booster pump and the turning gear must operate reliably for at least 2 hours on end; 7）Select steam supply accordingly and confirm that the steam supply meets the relevant requirements and the steam pipe before the main steam valve is sufficiently heated; 10.2.2.12
Press “BFPT Reset” on the MEH control panel and latch on the small steam turbine;
10.2.2.13
Enter 500r/min as the target rotating speed; After confirmation, the small steam turbine is
started and the flow of the control valve starts to escalate. Check that the turning gear automatically trips. The rotating speed will automatically rise to 900r/min with a speed of 300r/min/min. Keep the speed for less than 5min; 10.2.2.14 Enter 2,000r/min as the target rotating speed; after confirmation, the rotating speed will automatically rise to 2,000r/min with a speed of 300r/min/min. Heat the unit for 15min; 10.2.2.15 Input 2900r/min as the target rotating speed; After confirmation, the rotating speed rises automatically to 3,000r/min with a speed of 300r/min/min. Heat the unit for 10min. Check that 214
everything goes well and slowly open outlet valve of the steam-operated feed pump to observe the change in flow rate; 10.2.2.16 The first critical rotating speed of the unit is 2,336r/min and the second critical rotating speed is 7,133r/min. When the rotating speed reaches the critical value, the rate of the unit automatically increases to the maximum. At this stage, it is ineffective to attempt any modification of rate; 10.2.2.17 Push the “BOILER AUTO CTRL” button on the MEH panel to effect an automatic control; 10.2.2.18 If the inlet steam pressure of the small steam turbine is low, the speed control system will automatically switch to a higher pressure to admit part of the main steam and meet the requirements for a larger load. When the main steam turbine load reaches the 4th extraction pressure and can meet the requirements of the small steam turbine, the speed control system will automatically effect a switchover to cut off high-pressure inlet steam and drive the water pump by low-pressure inlet steam (if high-pressure steam supply is selected for a startup, the small steam turbine will switch from low-pressure steam to high-pressure steam after the unit load reaches 40% of the rated load); 10.2.2.19 After the main steam turbine load reaches 3 00MW, start the second steam pump; 10.2.2.20Close all steam trap valves between the small turbine cylinder and the steam pipes.
10.3. Shutdown of Feed pump 10.3.1 Shutdown of Electric Pump after Startup of Steam Steam Pump 10.3.1.1 Release the auxiliary oil p ump from interlock, start it and check that it works normally and the lube oil pressure is normal; no rmal; 10.3.1.2 Check that the steam pump attains to a rotating speed of 3,000rpm and commission the automatic control mode. Switch the speed control of the electric pump to the manual mode and gradually reduce the pump rotating speed. Shift the electric pump load wholly to the steam pump; 10.3.1.3 When the flow rate of the electric pump drops below 200t/h, the recirculating pump will automatically open; 10.3.1.4 Shut down the pump to observe the idle operation of the feed pump and the motor and check that the lube oil pressure is normal; 10.3.1.5 After the electric pump is shut down, switch the rotation con trol mechanism of the electric pump to automatic mode and commission the pump on standby; 10.3.2 Shutdown of Steam Pump 10.3.2.1 When the main steam turbine load drops below 50%, one steam pump may be shut down; 10.3.2.2 Before the shutdown of the steam-operated feed pump, trial-run the standby oil pump and DC oil pump to check that they work reliably; 10.3.2.3 When the unit load drops to 180MW, startup the electric pump as per the requirements to check that it operates reliably; 10.3.2.4 Switch the rotating speed of the first small steam turbine to be shut down to the automatic 215
mode; 10.3.2.5 Step down the steam pump rotating speed gradually. See to it that the rotating speed of the electric pump must be increased accordingly; 10.3.2.6 When the steam pump has a flow rate less than 300t/h, the recirculating pump must open automatically; 10.3.2.7 After the full load of the steam pump is shifted to the electric pump, reduce the rotating speed of the steam pump below 3,000rpm and open the steam trap valve for the small steam turbine; 10.3.2.8 Trip the small steam turbine via the control panel or via the local control mechanism. Check that the main steam valve and the steam control valve are closed. The rotating speed of the small steam turbine drops; 10.3.2.9 When the rotating speed of the small steam turbine drops to 140r/min, the turning gear must be commissioned automatically; 10.3.2.10 Close the electric steam inlet valve for the small steam turbine and open all the steam trap valves; 10.3.2.11 If the steam pump is used for a standby heating source, the seal gland and the turning gear should operate continuously. The steam vent butterfly valve must be open. Maintain pipe heating for the small steam turbine; 10.3.2.12In the event of a seal gland steam supply, the turning gear must not be shut down. If the main steam turbine and the small steam turbine are synchronously shut down, seal gland steam supply may be stopped. If the small steam turbine is shut down separately, close the steam vent butterfly valve and stop seal gland steam supply when the inner wall temperature of the cylinder flan flange ge drop drops s to to 100 100℃ .
10.4. Operation Monitoring and Adjustment of Feed pump System 10.4.1 Operation Monitoring and Adjustment of Electric Pump 10.4.1.1 Check that the pump, feed water pipes and equipment have no leak; 10.4.1.2 Check that the following parameters are normal: pump current, bearing vibration, bearing & motor coil temperature, feed water flow rate, inlet/outlet pressure, differential pressure on the two sides of the strainers of the main pump and the booster pump and motor air temperature; 10.4.1.3Check that the following parameters are normal: lube oil & service oil pressure, temperature, bearing oil flow rate and the differential pressure on the two sides of the oil strainer. Check that the oil tank level and oil quality are acceptable and the oil pipe has no leak; 10.4.1.4 Check that the scoop tube position and the automatic control are normal; 10.4.2 Operation Monitoring and Adjustment of Steam Pump 10.4.2.1 Check that the following parameters are normal: booster pump current, motor vibration, sound and bearing temperature; 10.4.2.2 Check the steam pump body as is done for the electric pump; 10.4.2.3 Check that the small steam turbine control system works properly; 216
10.4.2.4 Check that the following parameters of the Lubricating oil system for the small steam turbine are normal: service oil pressure/temperature, bearing oil flow rate and the differential pressure on the two sides of the oil strainer. Check that the oil tank level and oil quality are normal and there is no leak in oil pipes; 10.4.2.5 When the steam-operated feed pump is in operation, monitor the exhaust steam temperature to avoid cylinder overheating; 10.4.2.6 If the rotor is stationary, do not supply steam to the steam seal for a long time. This is intended to prevent a steam seal deformation.
10.5. Feed pump System Accidents Treatment 10.5.1 Emergency Shutdown of Steam Pump 10.5.1.1 Enforce an emergency shutdown in case of a small steam turbine vacuum break in the following cases: 1) When the steam pump vibrates violently or there is audible noise of metallic abrasion or impact within the small steam turbine or the pump; 2) When the rotating speed of the small steam turbine increases to 5,972r/min and the emergency protector fails; 3) When the small steam turbine is subject to a water impact; 4) When the small steam turbine oil system catches fire, the fire fails to be quickly smothered and the safe operation of the unit is endangered; 5) When oil supply to the steam pump bearing is exhausted or the return oil temperature exceeds 75℃ ; 6) When the oil tank level of the small steam turbine drops to the lower limit and the measures taken fail to maintain the oil level; 7) When the lube oil pressure drops to 0.08MPa but the protection mechanism fails; 8) When the booster pump motor gives off smoke and catches fire; 9）When the axial displacement reaches +0.9mm or -0.9mm but the protection mechanism fails; 10）When vacuum drops below 47.7KPa(a) but the protection mechanism fails; 11）When the the Babbitt Babbitt metal metal temperature temperature of the the bearing bearing reaches reaches 110℃ ; 12）When the fluctuation of the small steam turbine rotating speed cause a failure to control the water level of the steam drum; 10.5.1.2 Emergency Shutdown of Small steam turbine without Breaking Vacuum 1) When the speed control system of the small steam turbine experiences violent vibration and operation fails to be maintained; 2) When the steam/water supply pipe bursts and fails to be isolated; 3) When the exhaust steam pressure continues to climb and fails to be restored; 4) When the steam pump has a serious vaporization; 5) When the oil system has a leak and operation is interrupted; 6) When the main body of the pump has a serious leak and large quantities of steam/water spurt, 217
which endangers the safe operation of pumps; 7) When the booster pump motor has an overcurrent and fails to be corrected; 8) When the pump protective action value is reached but the protection mechanism fails to work; 10.5.1.3 When both steam pumps are commissioned, if one pump is shut down in the emergency mode, the electric pump must automatically start in a parallel mode; 10.5.1.4 If an emergency shutdown of the small steam turbine is required, push the “SHUT DOWN” button or operate the emergency breaker lever locally. Check that the main steam valve and the steam control valve are shut and the rotating speed drops. If a vacuum breaking is required, shut the steam vent butterfly valve and the steam trap valves of the small steam turbine before cutting off steam supply to the seal gland; 10.5.1.5 Complete other operations required for a small steam turbine shutdown; 10.5.2 Emergency Shutdown of Electric Pump 10.5.2.1 Emergency Shutdown of Electric Pump 1) Pump motor or coupler gives off smoke o r catches fire; 2) Any bearing metal temperature or return oil temperature exceeds the limits, or oil supply to the bearing fails, or the bearing gives off smoke; 3) The steam supply pipes or feed water pipes burst and fail to be isolated; 4) The electric pump has a serious vaporization 5) The pump motor has an overcurrent, which fails to drop to no rmal; 6) The main body of the electric pump has a serious leakage, which spurts large quantities of steam/water and endangers pump operation safety; 7) When the pump protective action value is reached but the protection mechanism fails to work; 8) The pump vibrates violently and t here is clear and audible metallic abrasion or impact sound; 9) The oil system electric pump has a serious leakage, the oil level drops to the lower limit and corrective measures fail. 10.5.2.2 In the case of an emergency shutdown of the electric pump, operate in the central control room or push the emergency button locally. 10.5.2.3 Check that the auxiliary oil pump has been automatically commissioned; 10.5.2.4 Throw the scoop tube to zero and promptly shut the electric valve at the pump outlet and the midpoint tap valve. 10.5.2.5 Complete other operations required for the shutdown of the pump. 10.5.3 Vaporization of Feed Pump 10.5.3.1 Symptoms 1) The pump current oscillates and drops, the rotating speed of the steam pump oscillates and the booster electric pump/steam or has a current oscillation; 2) The outlet pressure of the e lectric/steam pump oscillates and drops; 3) The feed water flow rate oscillates o scillates and drops; 4) The contact surfaces and the seal glands at both ends have steam leakages 218
5) The interior of the pump gives off noise or impact noise, pump vibration escalates or the rotor floats at the end; 10.5.3.2 Causes 1) The deaerator pressure drops sharply; 2) The strainer at the pump inlet is clogged, causing an under-pressure at the inlet; 3) When the flow rate is low, the recirculating pump is not open; 4) The steam pump operates for too long a time at a low rotating speed; 5) The deaerator water level is to o low. 10.5.3.3 Treatment: 1) If the electric pump has vaporization, shut down the pump when the boiler is in the ignition process. Locate and correct the cause and restart the pump. If the vaporization of a loaded pump is caused by a low deaerator level, shift the load to the steam pump and shut down the electric pump immediately; 2) If the steam pump has a vaporization, start up the electric pump and shut down the steam pump immediately. immediately. Reduce the pump load according to the feed water flow. 3) Open the vent valve for the main body of the steam pump to discharge the steam. Do not restart the pump until the turning gear operates flexibly and restores to normal. Monitor the internal noise and vibration of the small steam turbine and the pumps. 11. Auxiliary Steam System
11.1. Pre-Start-up Check and Preparation 11.1.1 Carry out a cross examination of the auxiliary steam and confirm that the pipes have sound connections, the front and rear manual valves of the steam traps are open and the steam trap bypass valves are closed. If the system is commissioned for the first time or is to be decommissioned for a long time, use the bypass for drainage. The drainage should find its way into the floor drain before vacuum is created. After vacuum is created, the drainage must be poured into the condenser. 11.1.2 Before the auxiliary steam system is commissioned and close all the steam converter valves and isolating valves for all users; 11.1.3 Check that all control valves and electric valves are working properly an d closed; 11.1.4 Check that all temperature and pressure gauges are a re commissioned; 11.1.5 Confirm that the condenser con denser and the constant flash flas h tank are ready to accept drainage.
11.2. Auxiliary System into Operation 11.2.1 Commissioning of Auxiliary System 11.2.1.1 Check that the steam trap valves of the auxiliary steam header and of the steam supply pipes are open. Check that the auxiliary steam system has met all commissioning conditions; 11.2.1.2 Open the isolating valve connecting the boiler to the auxiliary steam manifold or the communication valve for the auxiliary steam manifold of the adjacent unit. Maintain the steam 219
pressure between 0.05MPa and 0.1MPa and heat the pipe for 20 minutes. Fully open the isolating valve between the boiler and the auxiliary steam manifold or the communication valve for the auxiliary steam manifold of the adjacent unit; 11.2.1.3 Slightly open isolating valve at the steam inlet of the auxiliary steam header. Maintain the header pressure between 0.05MPa and 0.1MPa and heat the header for 20minutes; 11.2.1.4 After the header heating process, adjust the isolating valve at the steam inlet of the auxiliary steam header to boost the pressure to 0.6MPa-1.2MPa. Check that the header temp temper erat atur ure e is is abo above ve 250 250℃ ; 11.2.1.5 After vacuum is established for the condenser, switch the auxiliary steam trap to the condenser. Check that the vacuum of the main steam turbine is normal and the condensate quality is normal; 11.2.1.6 Commission the auxiliary steam for different users a ccording to their needs; 11.2.1.7 When the cold reheater has a pressure higher than that of the auxiliary steam, switch to the cold reheater for steam supply to the header; 1）Open the electrical steam supply valve between the colder reheater and the header; 2）Commission automatic pressure control mechanism for the pipes between the cold reheater and the auxiliary steam. Check that the automatic control and the header pressure are normal; 3）Slowly close the steam supply isolating valve between the boiler (or adjacent unit) to the header. Check that the header has normal pressure; 4）The rear steam trap for the pressure control valve of the cold reheater must operate reliably; 11.2.1.8 When the 4th extraction has a pressure exceeding that of the auxiliary steam, switch to the 4th extraction for steam supply to the header: th
1）Open the electric valve between the 4 extraction and the auxiliary steam; 2）Check that the pressure and temperature of the header are normal and the steam supply control valve between the cold reheater and the auxiliary steam is automatically shut; th 3）Ensure that the steam trap of the 4 extraction is operating continuously;
11.3. Shutdown Shutdown of Auxiliary Steam System 11.3.1 Confirm that all users have stopped the use of steam. Switch steam supply for users of the shared system to the adjacent adjacen t unit. A prior prior consent of the shift supervisor must be obtained; 11.3.2 Shut the isolating valves leading to different users; th
11.3.3 Close the steam supply valves leading from the colder reheater, 4 extraction, adjacent unit and startup boiler to the header; 11.3.4 After the steam trap valve between the auxiliary steam system and the condenser is closed, open the steam trap valve for the auxiliary steam system and drain out the header and the pipes.
11.4. Operating Monitoring and Adjustment 11.4.1Check that the header heade r pressure and temperature are normal; 11.4.1Promptly switch the auxiliary steam supply and maintain the pressure within tolerance according to load changes; 220
11.4.1Check that the system has ha s no leak and the pipes have no vibration; 11.4.1Limits of Ope rational Parameters of Auxiliary Steam System
Item Item
Unit Unit
Boiler Steam Pressure
MPa
Boiler Steam Temperature emperat ure Cold Cold Reheate Reheaterr Steam Pressu Pressure re Cold Cold Reheate Reheaterr Steam Steam Tempera emperatur ture e th
4 Extr Extrac acti tion on Steam team Pres Pressu sure re 4th Extr Extrac acti tion on Steam team Tempe empera ratur ture e Heade Headerr Pres Pressu sure re Header Temperature emperat ure
Norm Normal al Value alue
ºC MPa
3.67 3.67
ºC
321
MPa MPa
1.05 1.052 2
ºC
363. 363.1 1
MPa MPa
0.6-1 0.6-1.29 .29
ºC
370
11.5. Accidents Treatment Treatment of Auxiliary Steam System 11.5.1 High Heade r Pressure 11.5.1.1 Symptoms 1) The header pressure is higher than the normal value. 2) The safety valve has a response; 11.5.1.2 Causes 1) The pressure control valve of the cold reheater is open by mistake; 2) The auxiliary steam pressure transducer has a fault; 11.5.1.3 Treatment 1) Switch the pressure control valve promptly to manual mode and close it. Monitor the pressure drop. Prevent a pressure drop of the auxiliary steam. Contact the maintenance staff for a solution; 2) If the pressure transducer has a fault and fails to monitor the pressure, no steam supply must be provided from the cold heater of the unit; 11.5.2 Low Heade r Pressure 11.5.2.1 Symptoms 1) The supply of seal gland steam and soot-blowing steam has too low a pressure and the system sounds an alarm; 2) The header has a low pressure; 11.5.2.2 Cause 1) The unit has a low load, the 4th extraction has a low pressure and the pressure control valve of the cold reheater is not correctly commissioned; 2) The auxiliary steam pressure transducer for the unit has an abnormality. 3) The unit consumes too much auxiliary steam; 11.5.2.3 处理Treatment 221
1) If the problem results from a malfunctioning pressure control, switch to the auxiliary steam header for steam supply and contact the maintenance staff; 2) If the problems results from too much auxiliary steam, reduce or readjust steam supply to a proper extent; 3) Ensure steam supply to the seal gland; 12. Generator Sealing Oil System
12.1. Pre-Startup Check 12.1.1 Finish the operations as specified by General Rules for Pre-Startup Check of Auxiliary
Equipment and System; 12.1.2 Check that the valve is in a correct position by pushing the valve check card prior to startup. 12.1.2 Check that the Lubricating oil system for the main steam turbine has been commissioned and is operating reliably; 12.1.3 Check that the interlock protection test on the sealing oil system has been passed and the system has been commissioned; 12.1.4 Check that the sealing oil vacuum box has been refilled and the oil level is normal; check that the air exhaust header is operating normally and the sealing oil pumps have all been refilled;
12.2. Sealing Oil System in Operation 12.2.1 Start a smoke exhaust fan of the air e xhaust header to confirm that the negative pressure is between -25 mmH2O ~ -50 mmH2O. Check that the fan is working properly. Commission another smoke exhaust fan in the standby mode; 12.2.2 Open the isolating valve of the main steam turbine between the lube oil to the sealing oil system; 12.2.3 Check the differential pressure control valve works properly and the oil/gas differential pressure is normal; 12.2.4 Check that the floater sealing oil tank has properly oil drainage. Open the bypass valve of the floater oil tank when the internal pressure falls below 50kPa; 12.2.5 Check that the sealing oil expansion header has normal oil level and no alarm signal; 12.2.6 ；Conduct a gas displacement for the generator in the mode where sealing oil is provided for the lube oil of the main steam turbine bearing; 12.2.7 ； After all the gas in the generator is displaced with acceptable purity hydrogen, commission the sealing oil system in the normal working mode; 12.2.8 Commission the oil/hydrogen differential pressure control valve in the automatic mode and check that the differential pressure is normal; 12.2.9 Start the sealing oil vacuum pump and maintain the vacuum degree around -0.07MP; 12.2.10 Start a main sealing oil pump and open the oil outlet valve to check that the outlet pressure is normal. Start the sealing oil recirculating pump and check t hat it works reliably; 12.2.11 After the oil level in the sealing oil vacuum tank returns to normal, open the evacuation 222
valve widely to increase the vacuum degree to the rated value (between -0.09~-0.096KPa) 12.2.12 Check that the oil/hydrogen differential pressure control valve for the sealing oil is working reliably and the differential pressure is normal; 12.2.13 Check and confirm that the floater sealing oil tank has normal oil level. When the interior pressure exceeds 50KPa, open the inlet/outlet valves of the tank and close the bypass valve; 12.2.14 After the sealing oil system operates stably, confirm that the inlet/outlet oil valves of another main sealing oil pump and of the DC sealing oil pump are open. Actuate the interlock on standby and confirm that the standby pump has no reversed rotation; 12.2.15 Check that the sealing oil system operates properly before charging hydrogen into the generator to increase the pressure to 0.414MPa.
12.3. Operation and Maintenance 12.3.1 Ensure that the oil/hydrogen differential pressure control valve of the sealing oil is correctly adjusted. When the rotor is stationary, maintain the oil/hydrogen differential pressure between 0.036MPa and 0.076MPa; when the rotor is in operation, maintain the oil/hydrogen differential pressure between 0.05MPa and 0.07MPa. Too high or too low a differential pressure is unacceptable. This is intended to prevent a hydrogen leak or oil ingression into the generator; 12.3.2 Commission one sealing oil strainer and maintain the other on standby. Clean the strainer on a regular basis; 12.3.3 The vacuum oil tank and the floater oil tank for the sealing oil must have normal oil level. Vacuum degree must exceed -0.088MPa; 12.3.4 While the sealing oil vacuum tank is in normal operation, maintain the vacuum above -0.09MPa to separate and drain the vapor in the oil; 12.3.5 Check if the oil separator of the sealing oil vacuum pump has accumulated water in it. If there is accumulated water, water, drain it immediately; 12.3.6 Check the oil/water detector on a regular basis to check if there is accumulated water. If there is accumulated water, check the system operation; 12.3.7 While the sealing oil system is in operation, the vent valves on top of the floater oil tank must not be shut; 12.3.8 The sealing oil system of the generator operates in any of the following modes in order to provide sealing for hydrogen in the generator under different conditions; 12.3.8.1 While the generator is in normal operation, commission one of the main sealing oil pump and maintain the other one on standby. The oil supply comes from the lube oil for the main steam turbine; 12.3.8.2 When the main sealing oil pump fails or the AC power supply fails, switch to the DC sealing oil pump to intensify monitoring of hydrogen purity. When hydrogen purity drops perceptibly, perceptibly, drain the pump and replenish it with hydrogen o nce every eight hours; 12.3.8.3 When the AC/DC sealing oil pump fails, the oil/hydrogen differential pressure is maintained by the lube oil for the main steam turbine. Enforce an emergency shutdown and drain 223
the hydrogen. Reduce the internal pressure to 0.02-0.05MPa; 12.3.8.4 While the Lubricating oil system of the main steam turbine fails, the sealing oil system can operate independently. Maintain a high vacuum degree for the sealing oil vacuum tank. A high vacuum degree will maintain the sealing oil for short-term operation; 12.3.10 Limits of Operational Parameters of Sealing Oil System
Upper
Lower
Limit
Limit
-
-
≤70
-
-
m
0 (Oil tank center line)
65-75
35-45
MPa
-0.09～-0.096
-
-0.088
-
-
Item
Unit
Normal Value
Sealing Oil Temperature
℃
35-45
℃
≤75
℃
Vacuum Oil Tank Level Vacuum Oil Tank Vacuum
Sealing Pad Return Oil Temperature Sealing Oil Return Oil Temperature
Oil/Hydrogen Differential Pressure
Oil pressure exceeds MPa
hydrogen pressure 0.056±0.02
12.4. Sealing Oil System Shutdown Shutdown 12.4.1 Shutdown Conditions 12.4.1.1 All hydrogen within the unit has been displaced with air with purity above 95%. The internal pressure is above 50KPa; 12.4.1.2 The turning gear of the turbine has stopped (the sealing oil system must not be shut down when the rotor is rolling, otherwise the sealing pads will be damaged); 12.4.2 Sealing oil System Shutdown 12.4.2.1 Release the standby main sealing oil pump and the DC sealing oil pump from the interlock; 12.4.2.2 Shut down the sealing oil vacuum valve; 12.4.2.3 Decommission the sealing oil pump and the recirculating pump; 12.4.2.4 Shut the isolating valve for lube oil supply to the sealing oil; 12.4.2.5 Check and confirm that the oil/water detector doesn’t sound an alarm; otherwise, open the bypass valve for the floater oil tank to reduce the oil level in the expansion header; 13. Generator Hydrogen Cooling System
13.1. Gas Displacement Mechanism for Hydrogen Cooling System 13.1.1 Gas displacement should be conducted when the rotor is stationary or when the turning gear is operating (Gas consumption rockets up when the turning gear is in operation). 13.1.2 Before the hydrogen cooling system is commissioned, displace the air with carbon dioxide. 224
When the carbon dioxide content in the unit exceeds 85%, displace carbon dioxide with hydrogen; 13.1.3 When the hydrogen cooling system is decommissioned, displace hydrogen with carbon dioxide. When the carbon dioxide content in the unit exceeds 95%, displace carbon dioxide with air; 13.1.4 Maintain the gas pressure in the unit around 0.02MPa-0.03Mpa all through the gas displacement process; 13.1.5 The operation of the hydrogen dryer must be synchronized with the gas displacement process for the generator; 13.1.6 Vent the following valves at regular intervals during the whole gas displacement process. Each venting operation must continue for 5 minutes. One venting operation is needed before the purity of each gas approaches the specified value (purity: up to 95%). The valves are closed after the venting process; 13.1.6.1 Vent Valve S-79 is used for the vent pipes at the excitation end of the sealing oil expansion header; 13.1.6.2 Vent Valve S-78 is used for the vent pipes at the steam end of the sealing oil expansion header; 13.1.6.3 Displaced Gas Outlet Valve 142 is used for the hydrogen dryer; 13.1.6.4 Blow-Down Valves 126 and 127 are used for f or Oil/Water Detectors A and B; 13.1.6.5 Valve 104 is used for the generator gas purity detection pipes; 13.1.7 When operating the vent valve of the sealing oil expansion header, do it slowly to control the pressure drop speed for the interior of the unit and prevent large fluctuations of the oil level from causing oil infiltration into the generator; 13.1.8 During the gas displacement, remove the hydrogen hydrograph on the inlet/outlet pipes of the dryer and open the bypass valve; 13.1.9 During the gas displacement, check that the sealing oil system works properly for the generator and the oil/gas differential pressure is maintained around 0.056MPa; 13.1.10 During gas displacement for the generator, fire operations or electrical operations are prohibited around the hydrogen system; 13.1.11 Before the hydrogen inflow/outflow process, commission the rooftop-mounted ventilator. 13.1.12 During the gas displacement for the generator, check the oil levels in the main oil tank, vacuum oil box, return oil expansion h eader, floater oil tank and generator leak detector;
13.2. Pre-Startup Check of Hydrogen Cooling System 13.2.1 Finish the operations as specified by General Rules for Pre-Startup Check of Auxiliary
Equipment and System; 13.2.2 Check that the valve is in a correct position by pushing the valve check card prior to startup. 13.2.3 Confirm that the main steam turbine Lubricating oil system and the generator sealing oil system have been correctly commissioned. If the pressure in the generato r is below 50KPa, the oil for sealing the gas within is directly supplied by the main steam turbine lubricating oil system; 225
13.2.4 Check that the quantity of carbon dioxide is adequate; 13.2.5 Contact the chemical engineer for preparation of an adequate quantity to maintain a normal pressure for the hydrogen manifold; 13.2.6 The operation of the hydrogen dryer must be synchronized with the gas displacement process for the generator; 13.2.7 Finish the water filling and venting operation for the water side of the hydrogen cooler and commission automatic temperature control for the cooler; 13.2.8 Contact the heat engineer, who must provide at least 2 hours of electric preheating for the gas displacement detector; 13.2.9 During the gas displacement process for the generator, fire operations or electrical operations are prohibited around the hydrogen system;
13.3. Hydrogen Cooling System in Operation 13.3.1 Displace the air with carbon dioxide; 13.3.1.1 Check that the inlet valves (A and B) of the hydrogen pressure reducer are shut; 13.3.1.2 Open the outlet/inlet valve (11) for carbon dioxide control; 13.3.1.3 Open the carbon dioxide inlet valve (117) of the gas displacement control station for a generator gas displacement; 13.3.1.4 Open the hydrogen outlet valve (120) of the gas displacement control station for the generator; 13.3.1.5 Open the gas outlet valve (119) of the gas displacement control station for the generator. Adjust the opening of the valve to control the internal pressure within the range of 0.0 2-0.03MPa; 13.3.1.6 Open the isolating valves (140 and 144) of the inlet pipes of the analyzer and adjust the gas inflow into the analyzer; 13.3.1.7 Open the outlet valve for the carbon dioxide cylinder; 13.3.1.8 Adjust the pressure reducer for carbon dioxide control and maintain the pressure between 0.05MPa and 0.1MPa for the reducer. Make sure that the carbon dioxide inlet pipe must not have dews within 3 meters of the generator. When the outlet pressure of the carbon dioxide cylinder drops to 0.5MPa, use another cylinder; 13.3.1.9The indication of carbon dioxide purity must be 85%. Contact the chemical engineer for a sampling check; 13.3.1.10 When the purity attains to 90%, close the cylinder outlet valve; 13.3.1.11 Close the inlet/outlet valve (11) for carbon dioxide control; 13.3.1.12 Close the carbon dioxide inlet valve (117) of the control station for generator gas displacement; 13.3.1.13 Close the hydrogen outlet valve (120) of the control station for generator gas displacement; 13.3.2 Displacement of Carbon Dioxide with Hydrogen 13.3.2.1 Open the carbon dioxide outlet valve (121) of the control station for generator gas 226
displacement; 13.3.2.2 Open the gas outlet valve (119) of the control station for generator gas displacement; 13.3.2.3 Open the inlet/outlet valves (3 or 5; 4 or 6) of the hydrogen pressure reducer; 13.3.2.4 Open the inlet/outlet valve (1 or 2) for hydrogen control; 13.3.2.5 Adjust the outlet pressure of the hydrogen pressure reducer to control the inlet hydrogen pressure and maintain the internal pressure between 0.02MPa and 0.03 MPa; 13.3.2.6 The hydrogen purity in the generator must attain to 95%; contact the chemical engineer for a sampling check; 13.3.2.7 After the hydrogen purity is acceptable, keep the following valves open: hydrogen outlet valve (120) for the control station, gas outlet valve (119) and carbon dioxide outlet valve (121) of the control station. Boost the hydrogen pressure for the unit and the sample gas will be delivered to the gas analyzer for hydrogen purity determination; 13.3.2.8 Switch the generator sealing oil system to normal mode; 13.3.2.9 Raise the hydrogen pressure in the generator step by step to 0.414MPa. Check that automatic control mechanism for the sealing oil pressure works properly and maintain the oil/hydrogen differential pressure around 0.056MPa; 13.3.3 Commission the hydrogen dryer to operation; 13.3.4 Open the inlet/outlet valve of the hydrograph on the inlet/outlet pipes of the hydrogen drier, close the bypass valve and commission the hydrograph. Check that the indicated dew-point temp temper erat atur ure e is equ equal al to to or bel below ow -21 -21℃ .
13.4. Operation and Maintenance of Hydrogen Cooling System 13.4.1 Check that the interior of the generator has proper hydrogen pressure, purity and humidity; 13.4.2 Check that the inlet/outlet hydrogen temperature and the automatic temperature controller of the hydrogen cooler are normal; 13.4.3 Check that the hydrogen supply pressure and the hydrogen pressure reducer are normal; 13.4.4 Check that there is no water/oil accumulation in the leak detectors at regular intervals. If there is water/oil, analyze and correct the cause. If necessary, increase draining frequency and report to the shift supervisor; 13.4.5 Check the blow-down valves on the inlet/outlet pipes of the hydrogen purity analyzer and arrange for drainage at regular intervals to ensure proper operation of the purity analyzer; 13.4.6 Drain and check the hydrogen drier at regular intervals. If any rise in drainage is detected, check that the drier operates reliably and correct the fault; 13.4.7 Check the surroundings of the generator on a regular basis to ensure that the hydrogen content in the potential accumulation areas is within a normal range; 13.4.8 Monitor any hydrogen leak. The normal leak of this unit must be below 13-19m3/d. If the leakage increases, identify the cause and ask the responsible department for coordination; 13.4.9 For gas discharging in normal unit operation, use the hydrogen vent valve (120) of the control station. Do not use the vent valve on top of the sealing oil expansion header; 227
13.4.10 Limits of Operational Parameters of Hydrogen Cooling System
Normal
Upper
Lower
Value
Limit
Limit
Item
Unit
Hydr Hydroge ogen n Suppl Supply y Mani Manifo fold ld Pres Pressu sure re
MPa MPa
＜3.2
-
-
Hydrogen Supply Dew Point
℃
≤-21
-
-
In-Gener nerator Hydrogen Pre Pressure
MPa
0.414
-
-
Dryer Outlet Temperature
℃
18
-
-
In-Generator Hydrogen Purity
%
＞98
-
96
℃
46
-
-
%
＜2
-
-
Hydrogen Cooler Outlet Temperature Ambient Oxygen Content
13.5. Shutdown of Hydrogen Cooling System 13.5.1 Stop the hydrogen drier; 13.5.2 Check if there is an adequate quantity of carbon dioxide; 13.5.3 Close the hydrogen outlet/inlet valve (1 or 2) and the inlet and outlet valves of hydrogen pressure reducer (3 and 5; or, 4 and 5); 13.5.4 Remove the hydrogen hydrograph on the inlet/outlet pipes of the hydrogen drier. 13.5.5 Close the carbon dioxide outlet valve of the control station for generator gas displacement; 13.5.6 Follow these steps when displacing hydrogen with carbon dioxide: 13.5.6.1 Slowly reduce the interior hydrogen pressure to 0.02MPa-0.03MPa, using the gas displacement& outlet valve of the hydrogen drier. Adjust the operation mode of the sealing oil system promptly to switch to the main steam turbine Lubricating oil system for supply of sealing oil. Prevent oil penetration into the generator; 13.5.5.2 Open the main inlet valve (11) for carbon dioxide control; 13.5.5.3 Open the carbon dioxide inlet valve (117) of the control station for generator gas displacement; 13.5.5.4 Open the hydrogen outlet valve (120) of the control station for generator gas displacement; 13.5.5.5 Open the gas outlet valve (119) of the control station for generator gas displacement and adjust the opening of the valve to control the specified internal pressure; 13.5.5.6 Open the outlet valve of the carbon dioxide cylinder; 13.5.5.7 Adjust the carbon dioxide pressure reducer to maintain the pressure around 0.4MPa. When the outlet pressure drops to 0.5MPa, use another cylinder; 13.5.5.8 The indication of carbon dioxide purity must be 95%. Contact the chemical engineer for a sampling check; 13.5.5.9 If the purity is acceptable, close the outlet valve of the cylinder; 228
13.5.5.10 Close the inlet/outlet valve (11) for carbon dioxide control; 13.5.5.11 Close the carbon dioxide inlet valve (117) of the control station for generator gas displacement; 13.5.6 Follow these steps when displacing carbon dioxide with air: 13.5.6.1 Check and confirm that the inlet/outlet valves of the hydrogen pressure reducer and the inlet/outlet valves (11) for carbon dioxide control have been shut; 13.5.6.2 Close the carbon dioxide inlet valve (117) of the control station for generator gas displacement; 13.5.6.3 Close the hydrogen outlet valve (120) of the control station for generator gas displacement; 13.5.6.4 Open the carbon dioxide outlet valve (121) of the control station for generator gas displacement; 13.5.6.5 Open the gas outlet valve (119) of the control station for generator gas displacement; 13.5.6.6 Open the displacement air on-off valve (115) and the displacement air inlet valve to charge the generator with air; 13.5.6.7 The charging of compressed air must not b e stopped unless the carbon dioxide content is below 5%; 13.5.6.8 After the displacement is finished, close all the a foresaid valves;
14 Generator stator water cooling system 14.1 Inspection of generator stator water cooling system before start 14.1.1 Carry out the operations in "General Principle of Inspection of Auxiliary Equipment and System before Startup (put into operation)"; 14.1.2 Check the valve position according to the requirements of system valve check card before start; 14.1.3 Make sure that the thermal interlock test is qualified; 14.1.4 Fill the ion exchange with water transferred by condensate tank and relief air in it. Close the air evacuation valve and drain valve after the air is evacuated; 14.1.6 Supply or change water of the stator cooling water tank with ion exchange. The supplying pressure is controlled within 0.2～0.7 MPa, and the water pressure of ion exchange ≯ 0.6MPa; 14.1.7 Supply water to the stator cooling water tank to ～3/4, and the water are qualified. 14.1.8 After the stator water cooling pump and stator water cooling condenser is filled with water and the air is evacuated, check the oil level of oil-bearing in the cooling water pump. Keep the inlet of internal cooling water pump open and the outlet closed; 14.1.9 Confirm the motor of hydrogen system and seal oil system run successfully; 14.1.10 Check the system with the backwash method when start for the first time or first start after the overhaul. Switch to the normal system when it is qualified a fter backwash. 14.2 Start of stator water cooling system 229
14.2.1 Start a stator water cooling pump, check the vibration, sound, bearing temperature, outlet water pressure and water level of stator cooling water tank of the pump set; 14.2.2 If the water temperature of the stator cooling water tank is lower than the temperature of hydrogen, then close the inlet and outlet valves of the stator water cooling motor, put the stator water cooling heater motor into operation and raise the temperature of the water to a
higher
temperature than that of hydrogen, and then switch back to the motor water inlet mode. 14.2.3 Put one of the stator water cooling condenser into operation and the other for standby. Close the inlet valve of the shell side and pipe side of the standby stator water cooling condenser, and open the outlet valve. 14.2.4 Set the stator water cooling pressure adjusting valve automatic, make sure that the water pressure of the stator coil is 0.196 MPa, and the stator water cooling flow is 92t/h. If the two can't be met at the same time, regard the flow requirement as priority, but the pressure can't exceed 0.35 Mpa; 14.2.5 Make sure the pressure difference of stator water cooling filter before and after should be normal＜0.055MPa, and there is no leakage in the system; 14.2.6 Check and adjust the flow between stator water cooling and ion exchange to be around 15t/h(250l/min), refer to chemical experiment and prove to be qualified; 14.2.7 Open inlet and outlet valves of the standby stator water cooling pump, put them into the link of stator water cooling pump; 14.2.8 Carry out temperature adjusting according to the temperature of the inlet stator cooling water. water. Be sure that that the temperatur temperature e of the inlet inlet stator stator cooling cooling water should be around around 45±3 45±3℃ , 2 ºC higher than the hydrogen temperature. Regulate the inlet cooling water of condenser to raise the temperature of stator cooling water if n ecessary. ecessary. 14.3 Maintenance of stator water cooling system 14.3.1 Check the pipes and equipments of the stator water cooling system to see if there is leakage. 14.3.2 Check the water level of the stator cooling water tank to see if it is normal, if not, replenish water. Regulate the water supplying pressure within 0.2 ～0.7 MPa, and the water pressure of ion exchange exchange is≯0.6MPa. 0.6MPa. Close Close the isolati isolation on valve valve after after replenishi replenishing ng water water. 14.3.3 Check the vibration, sound, bearing temperature, outlet water pressure and oil level of the bearing of the pump set, and put them into the link of stator water cooling pump; 14.3.4 If the pressure of the system is unstable, standby pump should get start without delay; 14.3.5 Check the stator inlet water pressure, inlet water flow, return water temperature, inlet water conductivity; 14.3.6 Check the inlet water temperature and automatic temperature control; make sure that the temperature of stator cooling water is higher than that of the hydrogen. If the water temperature rises, check the temperature, pressure of the cooling water and the operation of the temperature regulating valve of the stator cooling water. Switch the condenser and run in parallel if necessary. necessary. 230
14.3.7 Check the inlet and outlet pressure difference of the stator cooling water filter. If the pressure difference reaches 0.055MPa, run without the filter and get repaired. After reparation, flush the filter until the water is qualified and then put into operation. Mind to slow down the operation. 14.3.8 Check the outlet water conductivity, inlet water pressure and flow of the ion exchange. The flow should be less than 22.3t/h, and the inlet water pressure should be less than 0.6MPa, water temperature ＜60℃. If the stator stator cooling cooling water water conductiv conductivity ity of the system system could could be kept under under 0.5μs/cm, or the pressure lost of the ion exchange exceeds 0.098MPa, it indicates that the exchange resin is invalid, and needs to be replaced. 14.3.9 Fulfill the regular switch and test. The outage pump shouldn't be reversed when switch the pump, otherwise, close the outlet valve of the outage pump and get repaired. 14.3.10 When the temper temperature ature of of the outlet outlet water water of stator stator cooling cooling water water motor motor exceeds exceeds 78℃ , the inlet flow is less than 63t/h, the inlet water pressure is less than 0.089MPa, cut off the water for protection if any of the above situations occurs. 14.3.10 Operating parameters limits of the stator water cooling system
Item
Water level of stator cooling water tank
Unit
Normal value
mum
0＋60
mm
0
MPa
＜0.055
Pressure difference of inlet and outlet of stator cooling
Maxi
water filter
Mini mu
Remark
m 0－
60mm above the box axial
60
line is 0
＞
0.055 ≯hyd
Stator inlet water pressure
KPa
196
rogen
＞
press
89
ure Stator inlet water
℃
42～48
49
℃
60
74
t/h
92
uS/cm
<0.5
MPa
0.2～0.7
Replenishing water flow
t/h
＜15
Flow of ion exchange
t/h
15
temperature Stator outlet water temperature Stator cooling water flow Stator cooling water conductivity Replenishing water pressure
42
78℃ prot protec ecti tion on acti action on 72
1.0
22.3 231
≤63 t/h protection action
Inlet water temperature of
℃
ion exchange Outlet water conductivity of ion exchange
＞hydrogen
temperature uS/cm
<0.2
60
1.0
14.4 Stop of the stator water cooling system 14.4.1 Remove the interlock of the internal cooling water pump and stop the cooling water pump; 14.4.2 Carry out stator cooling water b ackwashing if necessary; 14.4.3 When When the outside outside temperature temperature is near 0℃ or the motor motor needs needs DC test, test, drain drain the water water in the stator coil off.
Appendix 1 Start-stop operation curve of the turbine
232
233
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2. Heat balance diagram
