印尼中爪哇 2×300MW 工程
湖北华电青山热电有限公司 2005 年
目录 CHAPTER 1 SECTION 1 SECTION 2 SECTION3
MAINTENANCE DURING THE OPERATION OF TURBINE ...................................- 3 ROUTINE MAINTENANCE DURING OPERATION ........................................................................ - 3 SUPERVISION AND REGULATION OF THE SAFETY AND ECONOMY DURING OPERATION ........... - 6 INSPECTION PROJECTS FOR THE OVERHAUL AND MINI-OVERHAUL OF UNITS ........................... - 9 -
CHAPTER 2 汽轮机自控维护 ......................................................................................................................- 12 SECTION1 SECTION2 SECTION3 SECTION4
INSTRUCTION ON ELECTRIC MONITORING SYSTEM OF STEAM TURBINE ............................... - 12 MANUAL OF EMERGENCY TRIPPING DEVICE OF STEAM TURBINE ............................................ - 33 INSTRUCTION ON AUTOMATIC OPERATION DEVICE FOR TURNING GEAR .................................. - 42 DIGITAL ELECTRO-HYRAULIC (DEH) CONTROL SYSTEM SPECIFICATIONS .......................... - 53 -
CHAPTER 3 辅机维护 ................................................................................................................................ - 110 SECTION1 SPECIFICATION FOR MAIN BODY OF STEAM TURBINE AND LINE DRAINAGE SYSTEM(N300-16.7/537/537-8) .................................................................................................................. - 110 SECTION2 N-17750 CONDENSER SPECIFICATIONS ................................................................................ - 117 SECTOION3 SPECIFICATION FOR PNEUMATIC CONTROL SYSTEM OF STEAM EXTRACTION CHECK VALVE OF
STEAM TURBINE（N300-16.7/537/537-8） ............................................................................................... - 130 SECTION4 SELF-SEALING TURBINE STEAM SEAL SYSTEM SPECIFICATIONS ......................................... - 134 SECTION5 MAINTENANCE OF CONDENSATE PUMP ................................................................................. - 148 SECTION6 FEEDWATER PUMP................................................................................................................ - 151 SECTION7 LP HEATER SYSTEM SPECIFICATIONS .................................................................................. - 160 CHAPTER4 汽轮机油系统维护 .................................................................................................................- 166 SECTION1 SPECIFICATION FOR LUBRICATING SYSTEM .......................................................................... - 166 SECTION2 DESCRIPTION OF INTEGRATED OIL TANK ............................................................................... - 174 SECTION3 MANUAL OF SHAFT-JACKING DEVICE .................................................................................... - 180 SECTION4 MANUAL OF OIL INJECTOR .................................................................................................... - 185 SECTION5 MAIN OIL PUMP DESCRIPTION................................................................................................... - 188 SECTION6 INSTRUCTION FOR SPILL VALVE ............................................................................................ - 190 SECTION7 INSTRUCTION FOR TWIN-TONGUE CHECK VALVE................................................................. - 194 SECTION8 OPERATING INSTRUCTION FOR OIL SMOKE SEPARATOR ....................................................... - 197 -
CHAPTER5 INSTRUCTION OF HYDROGEN、SEAL OIL、STATOR COOLING WATER SYSTEM FOR 300MW GENERATOR .......................................................................................................................- 199 SECTION1 GENERAL ........................................................................................................................... - 199 SECTION2 HYDROGEN CONTROL SYSTEM(SEE HYDROGEN CONTROL SYSTEM DIAGRAM)....................... - 199 SECTION3 SEAL OIL CONTROL SYSTEM(SEE THE SEAL OIL CONTROL SYSTEM DIAGRAM) ...................... - 204 SECTION4 STATOR WINDING COOLING WATER SYSTEM(SEE STATOR WINDING COOLING WATER CONTROL SYSTEM DIAGRAM)....................................................................................................................................... - 208 -
CHAPTER6
DESCRIPTION OF CIRCULATING WATER SYSTEM.............................................- 212 -
SECTION1 SECTION2 SECTION3 SECTION4
GENERAL SITUATION ............................................................................................................ - 212 DESIGN DESCRIPTION OF CIRCULATING WATER SYSTEM ....................................................... - 213 THE CONSTRUCTION AND INSTALLATION DESCRIPTION OF THE CIRCULATING WATER SYSTEM - 217 OPERATING MANAGEMENT DESCRIPTION OF CIRCULATING WATER SYSTEM .......................... - 218 -
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Chapter 1
Maintenance during the Operation of Turbine
Section 1
Routine Maintenance during Operation
Operation of turbine with load is one of important section during the production of electric power. It is the duty of operation persons of turbine to perform correctly rules and to operate, check, supervise and regulate strictly during operation, and the precondition to ensure the safe and economic operation of turbine devices. Working contents of the routine maintenance during the operation of turbine are: (1) To supervise the related devices and meters via supervising panel, transcribing readings periodically, inspecting circularly, measuring vibration periodically, to do the meter analysis, and to check the safe and economic condition of operation. (2) To regulate the related operating parameters and patterns, to go through the economic distribution principle of load, to enable the devices to operate under the best condition, to reduce the ratio of heat consumption and auxiliary power, and to increase the economic efficiency of operation. (3) To enhance the supervision of failed devices, fault systems and devices under a special operation pattern, to prevent the trouble occurrences and enlargement, to increase the utilization factor and to ensure the safe operation of devices. (4) To do various protective tests periodically and the normal tests and shift operation of auxiliaries. In short, the main roles of operation of power plants are: to supply the needed electric energy to users or power network continuously & safely & economically. I. The shift persons should do the following while the turbine normally operating: (1) To supervise & operate & regulate strictly, notice at any time the variation of indication of each meter and adopt the corresponding maintenance measures, and to fill in the operation logs. (2) To read meters every one hour and analyze the data. if the reading is different from the normal value, the cause should be found out immediately and the necessary measures should be taken. (3) To inspect the unit periodically, especially notice the temperatures of babbit of each trust bearing pad and each bearing, the oil return temperature, oil flow and vibration, operation and tightness conditions of the cooling system of generator and prevention of oil leakage and fire catching. (4) To do the listening inspection for each part of turbine, especially while the operating condition changes greatly. (5) To inspect periodically or contact with maintenance persons to clean the screens installed in the steam or water or oil system in terms of the exact condition during operation. (6) To regulate in time the steam pressure of shaft sealing, to prevent leaking steam caused by too high pressure from entering the bearing box, resulting in the deterioration of oil quality; and simultaneously prevent air leakage of low-pressure casing gland caused by too low pressure resulting in the drop of the condenser vacuum. (7) To keep the turbine operate under the economic condition, and the following conditions should be met: a) To retain the main steam temperature at the rating, steam pressure conform to the prescribed value of variable pressure operation curve of the unit, and the variation does not exceed the permissible range. b) The regenerative system should run normally, the outlet water temperature of heater should confirm to the designed value or in the range prescribed by the rules.
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c) To keep the condenser operating under the best condition, check the steam extraction temperature of turbine periodically and regulate it in time if necessary. d) The degree of supercooling of the condensate should not exceed the prescribed value. (8) To do the various periodic shifts and tests. (9) To clean the devices of turbine generator periodically II. Control parameters during the normal operation In order to ensure the safe and economic operation of turbine devices, operation persons should supervise and analyze the operating condition of devices via various meters and regulate if necessary except for a visual method, to retain the various value in the permissive range. The values which should often be supervised are: the load of turbine, temperature and pressure of the main steam, vacuum of the condenser, rotary speed of turbine (frequency) and running condition of rotary devices. The parameters which should often be inspected are: steam pressure of regulating chamber, steam pressure and temperature of each extraction port, main steam flow, water temperature and level of inlet and outlet of each heater, oil level of oil tank, anti-fire oil pressure, pressure and temperature of lubrication, vibration of each bearing, thermal expansion and its difference of the unit, axial displacement of rotor, metal temperature of trust bearing and main bearing, opening of steam regulating valve and wind temperature of outlet of generator and so on. Under the normal condition, the above parameters have a certain inherent connection, such as: while the load of generator is increased, the steam flow into the turbine will increase owing to the invariable main steam parameters, the opening of regulating valve is also increased correspondingly, the steam pressure of regulating chamber and steam extraction pressure of each section is increased proportionally (for the condensate unit), the steam temperature before each section is also increased, and the thermal expansion of the unit is increased; if the relationship between these parameters is out of rear during operation, there is something wrong with the unit. if the steam pressure of regulating chamber and each extraction port is higher than the pressure corresponding to the normal condition with this power, the scaling or block exist in the flowing part. Because the unit type is different, the value prescribed by operation rules of each unit have to be carried out, these parameters can be kept in the permissive changing range via check, analysis, regulation and maintenance, to ensure the safe and economic operation of the unit. III. Inspection during operation Inspection is one of the important measures to understand devices, grasp the operation condition, find the hidden trouble and ensure the safe operation of devices. Hence, the following matters should be done carefully and strictly: 1. Inspection of the turbine proper (1) The total expansion indication of turbine, oil return temperature and quantity, vibration, servomotor travel and action of regulating valve and so on. (2) Bearing: oil return temperatures of all the bearing pads, oil quantity, vibration, the leakage of oil baffle. (3) Cylinder: shaft sealing admission, running sound of the unit, relative expansion, vibration of exhaust casing and exhaust temperature. (4) Generator and exciter: wind temperature of outlet and inlet, cooling water pressure and temperature of each cooler etc.
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(5) The devices of turning gear: the handle should be arranged at the OFF position, and the operating power source should be right. (6) The main automatic stop valve: the indication of position of the main stop valve, smooth flowing of cooling water (7) The main meter panel: the indication of pressure and vacuum of steam, water and oil systems, relative expansion difference and indication of axial displacement. 2. Inspection of the pumps (1) Motor: current, interlock "on" position, wind temperature of outlet, temperature and vibration of bearing, running sound, good grounding wiring and firm foundational bolts. (2) Pump: the outlet pressure should be right, gland packing should be of no heating or watering, the running sound should be right, the cooling water of bearing pad should be smooth, the water discharge hopper has no block, the oil level of bearing is normal and quality of oil is good, the oil ring can carry oil normally and has no leakage, coupler hood is fixed well. (3) The insulation of tubes connecting with pump should be all right, its support rack is fast and has no leakage, and opening of valve should be normal. (4) The relative meters should be complete and perfect, and its indication should be correct. 3. Inspection of feed water pump Except for the above items, the following items should be inspected because the feed water pump has its own lubrication system: (1) Indication of the pressure of balance disk should be normal.
(2) Position of the water inlet and outlet valve of cooling wind chamber of motor of motor-driven feed water pump and the condition of wind temperature. (3) Oil and water temperature condition and oil pressure of outlet and inlet of oil cooler should be normal. (4) The operating condition of hydraulic coupler. 4. Inspection of other auxiliaries (1) The level of lubrication tank, anti-fire oil tank and auxiliary oil tank should be normal, the operation of flue gas exhauster. (2) Oil cooler: the temperature of outlet and inlet should be normal; waterside has no accumulated gas or leakage of oil and water. The oil pressure should be more than the water pressure. (3) Each oil pump, oil filter and low-level oil tank, the oil level should be normal. (4) The main air ejector and shaft seal air ejector: the pressure of working steam or water, vacuum, water seal of vacuum break valve should be normal, the rotary devices using vacuum pumps should have abnormality and each component should have no overheat. (5) Condenser: the water level of condenser, the pressure and temperature of the condensate outlet and inlet, the temperature of condensate and the position of switch of each valve. (6) HP and LP heaters: the water level, the pressure of extraction steam, the position of the switch of valve, the protective water source of hydraulic check valve should be put into operation, the working condition of water level regulation, the piping and flanges should have no leakage of water and steam. (7) Shaft seal cooler: water level, the condition of siphon well, the position of watering valve, the condition of steam extraction of exhaust outlet, the sufficient water flowing quantity. (8) Drain expander: the switch of valves should be right and have no leakage of steam. (9) Deaerator: the pressure, temperature and water level should be normal, the condition of steam extraction, and the position of switch of each valve, the working condition of water level regulator. Also, the flange of tube should have no leakage of water and steam
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and the safety valve should work normally. The abnormal condition should be analyzed carefully and its causes should be found out and eliminated if it is found during inspection. The measures should be taken if the abnormity cannot be eliminated immediately, to prevent the enlargement of the trouble, and the trouble should be recorded and reported. IV.
Test during the normal operation and shifting of auxiliaries In order to ensure the safety of the main devices, their protections and auxiliaries should be safe and reliable, to avoid the damage to the main devices or shutdown caused by the fault of protections or auxiliaries, so the following should be done: (1) To operate the main stop valve periodically. The load should be changed in a large range periodically for the turbine carrying a stationary load, to prevent the lever of regulating valve from logging.
(2) Water (steam) pressure check valve on each regenerative extraction pipe, check valve and safety valve on the regulating extraction pipe should be tested and verified periodically according to the rules. If a fault occurs to one check valve or safety valve, it should be eliminated immediately or the corresponding measures should be taken. (3) The reserve emergency oil pump and its self-starting installation should be tested periodically. In addition, this test should be done while the turbine starts or before the turbine is shut down. (4) The oil level should be done the movement test every day, and the accumulating water at the bottom of oil tank should be discharged periodically. (5) Various automatic protections, including annunciator and lighting signal, should be tested periodically during operation if possible. (6) The protection of HP heater should be tested periodically. If HP heater has no high-level protection or the protection is abnormal, it is forbidden to put into operation. (7) The sealing test should be done for the vacuum system periodically, in general, once every month. (8) The shifting test should be done for the auxiliaries periodically every day including the main air ejector, vacuum pump, condensate pump, boosting pump, drain pump, service water pump etc. The insulation condition of motor of the reserve pump (devices) should be supervised to prevent damage to the motor from fault enlarging as emergency start. In conclusion, the daily work is very complex during normal operation, so the operators should be with responsibility that the quality of the bank can be kept and the network can get the safe and economic supply.
Section 2
Supervision and Regulation of the Safety and Economy during Operation
Some important parameters during normal operation of turbine, such as the main steam parameters, vacuum of the condenser, axial displacement, expansion difference and the pressure of supervised section and so on, act as the crucial function to the safe and economic operation of turbine. Hence, these parameters should be supervised carefully during operation and regulated in time to retain in a prescribed range. I. The main steam parameters During the normal operation of turbine, the steam parameters may be deflected from the rating inevitably and temporarily. If the deflection is not more than the permissive range, it cannot damage the strength of the components of turbine, otherwise, it will result in troubles of reliability and safety of operation. While the initial and steam extraction pressure is
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invariable, the change of temperature of the main steam will result in the change of temperature of the whole thermal cycling source and the change of thermal efficiency of the circulation. If the temperature of the main steam rises, the ideal enthalpy drop in the turbine increases and the ability of doing work enhances. Oppositely, while the temperature of the main steam drops, the ability of doing working decreases and so the efficiency drops. Under the condition of complete opening of regulating valve, the seam flow through the turbine decreases along with the rise of initial temperature, and regulating blades may overload. The strength of metal will rapidly drop along with the rise of temperature. In addition, the creepage may occur to the metal with high temperature. So rapid overload and super temperature are dangerous, at present the manufacturer prescribes the upper limit of temperature, in general not more 5～8℃ than the rating. While the opening of regulating valve is given, the initial temperature drops and results in the increase of flow quantity; the enthalpy drop of regulating stage decrease, the enthalpy drop of the final stage increases, and the final stage is easy to overload; also, the initial temperature drops resulting in the humidity of extraction steam increases, the impulsion damage to the final stage blades increases; and the initial temperature drop will increase the axial thrust. So the initial temperature drop not only affects the economic efficiency of the unit operation but also threaten the safety operation of the unit. In order to ensure the safety, the load should be reduced while the initial temperature is less 15～20℃ than the rating. While the opening of regulating valve is invariable, initial temperature and backpressure are invariable and the initial pressure increases, all the stages of turbine will overload, thereinto, the final stage is most serious. Simultaneously, the rise of initial pressure will threaten the piping of turbine and other bearing components. The initial pressure drop does not affect the safety of the unit, but the output of the unit will drop. Hence, the main steam pressure is required to operate under the prescribed pressure; especially the unit operation should be retained according to the variable-pressure operating curve for the sliding-pressure operation unit. II. Vacuum of condenser Vacuum of condenser is namely the pressure of steam extraction of turbine, owing to the variation of steam load, the copper pipe is scaled, the tightness of vacuum system is deteriorated and the cooling water temperature changes, their values can be changed in a large range, directly affecting the safe and economic operation of the unit. While the vacuum drops, the total enthalpy drop of turbine will decrease, and the decrease mainly happens to the final stages. At this time, the stress of these stages will decrease and the reaction degree will increase. While the vacuum drops rapidly, the variation of reaction degree will cause the variation of axial thrust and the thrust bearing may have danger. In addition, if the vacuum is deteriorated severely, the temperature of extraction steam will rise, resulting in the variation of center of the unit, accordingly resulting in the nonpermissive vibration. So the vacuum of the unit is permitted to drop in a certain range during operation, or the load must be reduced, even the emergency shutdown should be done. While the vacuum increase, the enthalpy drop of the final stage of turbine increases, and the final stage may overload. Especially while the final stage reaches the critical flow condition, the further increase of enthalpy drop will be borne only by the final stage. The variation of condenser vacuum can greatly affect the economic efficiency of operation of the turbine. it mainly shows that the variation of vacuum will cause that of ability of doing work. So, the copper pipe should be kept clean during the practical operation, and the tightness of vacuum system should be kept qualified, to improve the economic efficiency of the unit operation.
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III. Monitoring of the pressure of supervised section In the condensing turbine, the pressure of steam chamber of the regulating stage and the pressure of extraction steam of each stage is directly proportional to the flow of the main steam. According to this theory, the operation of convection part can be supervised via the supervision of the pressure of steam chamber of the regulating stage and the pressure of extraction steam during operation. Hence, this pressure is called that of supervised pressure. In a common condition, the manufacturer gives the steam flow and pressure value of and each supervised section under the rating load of each turbine and the permissive maximum steam flow and the pressure value according to the calculating result of thermal and strength. The pressure of each supervised section is not identical under the same load even the same type of turbine because each unit has its own property. Hence, each unit should be measured according to the given data by manufacturer after installation or overhauling while the convection part is under the normal condition, to acquire the relationship among the load, main steam flow and pressure of supervised section, which acts as criteria for regular operation supervision. If the pressure of supervised section rises under the same load (flow), it shows that the convection area of the convection section decreases mostly because of the scaling, sometimes because some metal components are cataclastic or mechanical foreign matter is blocked in the convection part or the blade is damaged and deformed. So while a heater is out of service, the pressure of corresponding extraction steam section will rise if admission quantity of turbine is unchanged. Not only the pressure up of supervised section but also the pressure difference between each supervised section is noticed whether to exceed the prescribed value. If the pressure difference of a section exceeds the prescribed value, the working stress of this section of diaphragm and movable blade will increase, resulting in the damage to the devices. The severe scaling should be eliminated (in general, the pressure of supervised section of intermediate-pressure and LP unit raises relatively 15%, that of HP or above unit 10%); the following four kinds of methods are commonly used: (1) The turbine is shut down and the casing is opened, with a mechanical method. (2) To rinse with heated water under the slowly turning condition. (3) To rinse with wet heated steam under a low rotary speed. (4) To rinse with wet steam with load. IV. Supervision of axial displacement and the temperature of bearing pad 1. Axial displacement The index of the axial displacement of turbine rotor is used to supervise the working condition of the thrust bearing; the axial thrust functioning on the rotor is borne by the thrust bearing, to ensure the reliable axial clearance between movable and stationary parts. Too much axial thrust or abnormality of operation of bearing will result in the burning and damage to the thrust pad, to produce the damage to devices caused by the wear of movable and stationary part. Various turbines are equipped with axial displacement indicator, which is used to supervise the working condition of the thrust pad; the turbine should be forced to shutdown immediately if the displacement exceeds the permissive limit value, to prevent the convection part from damage. Different types of units have different ZERO positions of indicators. The number of positive value indicated by the axial displacement shows the axial displacement quantity at the thrust disk during operation of turbine. So, the indicators are arranged near the thrust pad. In general, the thrust clearance of an integrated thrust pad is in a range of 0.4 to 0.6mm or so.
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The main steam pressure of the turbine is high and its temperature is low, especially the water enters cylinder, resulting in a great axial thrust. So, the axial thrust will change greatly if the vacuum is low or the convection part is scaled. If the displacement is found to increase during operation of the unit, the turbine should be examined throughout, to listening to its inner sound and measure the vibration of bearing, and simultaneously to supervise the variation of the thrust pad and oil return temperature, in general, the babbitt temperature of the thrust pad is not more than 95℃ and the oil return temperature is not more than 75℃, while the temperature exceeds the permissive value, the load should be reduced to enable it to restore to the normal even if the displacement indication is not too much, if the indication exceeds the permissive value to cause the protective action to trip, the generator should be paralleled off and shut down. At this time if the protection does not act, it should be checked carefully. 2. Temperature of bearing pad The bearing of turbine rotates in the bearing pad, causing the temperature up of lubricating oil and bearing pad. Too high temperature of bearing pad will threaten the safety of bearing. The temperature of bearing pad can be supervised via supervision of the temperature up of lubrication during operation, in general, the temperature up of lubrication should not exceed 10 to 15℃, but it acts only as auxiliary supervision because the oil temperature lags behind that of metal and cannot show immediately the variation of bearing pad temperature. In order to make the bearing pad operating normally, the temperature of oil supplying to bearing pad is prescribed definitely, in general the specified temperature is within 35 ～ 45 ℃.
Section3
Inspection projects for the overhaul and mini-overhaul of units
In order to keep the unit can operate safely and economically for long time. Perform the mini-overhaul once each time when the unit has been in operation for 4 to 8 months accumulatively. Eliminate the defects occurred during operation in time and replace the damaged components. 1
Imperative inspection items for mini-overhaul 1.1 Check each support bearing and thrust bearing, and check whether there are the phenomenon of serious wearing, picking, crack, decrustation, etc. with the babbit alloy surface so as to treat in time. 1.2 Check main oil pump and tooth coupling of main oil pump to ensure the safe operation. 1.3 Take the static test of control system, oil spray test of emergency stopper and over speed test again after the mini-overhaul so as to confirm the reliable operation of control and security system.
2
Imperative inspection items for overhaul 2.1
Overall inspection 2.1.1
Check whether there are the phenomenon of leakage and erosion at the
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steam casing split; 2.1.2 Check and record the raise degree of rotor and each journal; Check and record the longitudinal and transverse level of bearing box and steam casing split; 2.1.3
Check and record the flow clearance and gland clearance;
2.1.4 Remove the connection bolts of coupling, check and record the change of alignment of coupling. 2.2
Rotor inspection 2.2.1
Clean the impeller and impeller blade and remove the scale.
2.2.2 Check the axial run-out of each part and run-out of end face. Check the cylindricity of journal and the run-out of end face of thrust disk. 2.2.3 Check whether there are the defects of cracks, erosion and damage, etc. at each part of impeller, blade and rotating part. Perform the static frequency test to the long blades. 2.3
Bearing 2.3.1
Check the clearance and tightening force of bearing.
2.3.2 Check whether there are the defects of wearing, decrustation and cracks etc, with babbit alloy. 2.3.3 Check the platinum resistance thermometer, and replace the damaged elements. 2.4 2.5
Steam casing, holding ring and diaphragm 2.5.1 Check whether there are cracks with the HP inner casing and outer casing; 2.5.2 Check whether there are changes with the center of steam casing. 2.5.3 Check the split clearance of upper half and lower half. 2.5.4 Check whether there are cracks with the holding ring and diaphragm, and whether there are deformation with the diaphragm. 2.5.5 Check the bolts, gland gaskets and the thermocouple, and replace the damaged elements.
2.6
Valve 2.6.1 Disassemble and check whether the components of main steam valve and control valve have become loosen or damaged; 2.6.2 Check whether there are any change with the stem and the clearance of sleeve. Check whether there are crack and bend with the stems; 2.6.3 Check whether the touch between the valve disk and valve seat is tight; 2.6.4 Check whether there are any plastic deformation with the tooth gasket.
2.7
Control system 2.7.1 Check whether there are any erosion, crack with the control and safe part sets. Check whether there are any changes occurring with the fitting clearance. 2.7.2 Check whether the geometrical size and rigidity of spring of emergency
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stopper meet the requirement of drawing. Check whether there are cracks with the spring surface. 2.7.3 Perform the static test, tightness test of valve, oil spray test of emergency stopper and over speed test to the control system, 2.8
Oil system 2.8.1 Check the installation clearance of bearing of main oil pump, impeller and tooth coupling; 2.8.2 Clean the oil cooler and check whether there area damages with the copper pipe. 2.8.3 Check the filter and clean the oil box and oil filter.. 2.8.4 Check and clean the fan and smoke exhaust system. 2.8.5 Check and clean the oil pipe line.
2.9
Vacuum system 2.9.1 Check the ejector 2.9.2 Check the tightness of vacuum system.
2.10
Exhaust system
2.10.1 Check each check valve of exhaust and the control system; 2.10.2 Check the check valve of high exhaust and keep the tight closing; 2.11
Drain system:
Check each drain pipe line and keep them expedite and have no block. 2.12
Centering support system: Check each part of centering support system to see whether they meet the designing requirements; Check whether the anchor bolts have become loose; Check whether there are gapped phenomenon between the pedestal and filling iron.
2.13 Monitor system: Check the axial displacement, expansion differentia, vibration, and each element of monitor system. Indicate and adjust over again. 2.1.4 Monitor the main steam pipe and reheat steam pipe line about the change of creepage in long term.
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Chapter 2 汽轮机自控维护 Section1
Instruction on Electric Monitoring System of Steam Turbine
0-1 Overview of system The electric monitoring protection system of steam turbine (see D300N-003005U) consists of five parts, namely: shafting (D300N-003006C), oil pressure / vacuum (D300N-003008D), temperature (D300N-003009D), auxiliaries (D300N-003010U) and ETS (D300N-003011E). The instruction describes the arrangement of measuring points for shafting, the various signals in oil pressure / vacuum and temperature parts related to normal safe operation of turbine, the control logic of various electric equipment and motors, as well as the emergency tripping system (ETS) of turbine. All setting values for various signals concerned in this instruction are based on the setting values in the “Instruction on start-up and operation of steam turbine”. This instruction can be used as basis of corresponding design by the Design Institute. 0-2 Shafting 1
General The parameters of shafting for the steam turbine-generator unit to be continuous monitored are speed, zero speed, overspeed, differential expansion of HP/IP and LP turbines, axial displacement, thermal expansion of HP/IP casing, eccentricity, shaft vibration and vibration at cover of bearing pedestal. Unless specified otherwise, the following parameters shall be monitored by the MMS6000 Serial from EPRO Company. The description will be made for speed, displacement and vibration respectively hereafter.
2
Speed monitoring
2.1 Speed and zero speed The monitoring function here is realized by two transducers, one of which is for speed and the other for zero speed. Corresponding the speed measuring range of 0～5000 rpm there are 4～20mA DC signal outputs from the monitoring module here to the DCS system for display. The zero speed relay contact signal is output as one of the starting-up signals for the automatic turning gear of turbine while the speed falls down to 2 rpm. 2.2
“2 out of 3” electric overspeed protection There are 3 transducers used for electric overspeed protection. When the speed “n” of
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turbine is equal to or greater than 3300r/min and the “2 out of 3” logic requirement is met, the overspeed protection signal is sent out to the relay to trip the turbine after logic processing by the ETS. 2.3
Tachometer at head of unit A domestic made CS-1 type magnetic resistance speed transducer and a domestic made WZ-3 type intelligent transient tachometer with digital indication are adopted for the unit. The tachometer possesses such functions as two level overspeed alarm, zero speed alarm, fast speed indication, max. speed storing and reproduction, self check and calibration etc. Two level overspeed alarm and the zero speed alarm are output through relay contact. The tachometer is mounted on the cover of front bearing pedestal at head of unit.
3
Displacement monitoring
3.1 Differential expansion of HP/IP and LP turbines These two monitoring channels here are provided with a transducer for each, which output the corresponding 4～20mA DC signals to the DCS system for display. The alarm relay is actuated and the alarm signal is sent out while the differential expansion value of HP/IP turbine ≥ +6mm or ≤ -3mm and the differential expansion value of LP turbine ≥ +14mm. The emergency relay is actuated and the differential expansion over limiting signal is sent out while the differential expansion value of HP/IP turbine ≥ +7mm or ≤ -5mm,and the differential expansion value of LP turbine ≥ +15mm. 3.2
Axial displacement There are two transducers used for axial displacement monitoring. Corresponding to the axial displacement measuring range of -2mm～+2mm , the 4～20mA DC signals are output from monitor to the DCS system for display. The alarm relay is actuated and the alarm signal is sent out while the axial displacement value≥ 0.6mm or≤-1.05mm . The emergency relay is actuated and the axial displacement over limiting signal is sent out to ETS for tripping the turbine while axial displacement value of both transducers ≥ +1.2mm or ≤-1.65mm.
3.3
Eccentricity and phase-shifting The eccentricity and phase-shifting measuring is conducted by a transducer for each. Corresponding to the eccentricity measuring range of 0～100μm , these monitors output the 4～20mA DC signals to the DCS system for display. The alarm relay of monitor is
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actuated to send out the alarm signal while the eccentricity of
shaft exceeds its original
value by 30μm. 3.4
Thermal expansion of HP/IP casing There are two monitoring channels for thermal expansion of casing located at both sides of HP/IP casing of turbine respectively to monitor the casing expansion related to the foundation of unit. Two domestic made 50mm absolute expansion transducers and a completed absolute expansion monitor are used for HP/IP casing expansion. Corresponding to the HP/IP casing expansion measuring range of 0~50mm, the respective channel of monitor outputs the 4～20mA DC signal to the DCS system for display. The alarm and emergency relays of monitor are actuated to send out the corresponding alarm signal while the casing expansion exceeds the setting value I and II respectively.
4 4.1
Vibration Shaft vibration In order to monitor the radial vibration of rotor related to the bearings, the 1#～6# journal bearings of unit are provided with two monitoring channels for shaft vibration respectively, one of which is in horizontal (X) direction and the other in vertical (Y) direction. That means there are total 12 channels. Corresponding to the shaft vibration measuring range of 0～400μm, each channel of monitor will output the respective 4～20mA DC signal to the DCS system for display. The alarm relay in respective channel of the monitor is actuated to output the alarm signal while the shaft vibration in any channel ≥ 0.127mm. The emergency relay in respective channel of the monitor is actuated to output the emergency alarm signal while the shaft vibration in any channel ≥ 0.25mm.
4.2 Vibration at cover of bearing pedestal In order to monitor the absolute vibration of bearing pad related to the free space, the 1#～ 6# journal bearings of unit are provided with a monitoring channel for vertical vibration at cover of bearing pedestal respectively. That means there are total 6 channels with total 6 speed transducers. Corresponding to the bearing pad vibration measuring range of 0～100 μm, each channel of the monitor will output the respective 4～20mA DC signal to the DCS system for display. The alarm relay in respective channel of the monitor is actuated to output the alarm signal while the vibration at cover of bearing pedestal in any channel
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≥ 50μm. The emergency relay in respective channel of the monitor is actuated to output the emergency alarm signal while the vibration at cover of bearing pedestal in any channel ≥80μm 0-3 1
Oil Pressure /Vacuum
General The oil pressure/vacuum part of electric monitoring protection system of the steam turbine contains the destination of various signals related to the oil pressure and vacuum, as well as the various control logic of valves, oil pump and turning gear related to the oil pressure signal.
2
Tripping device for condenser low vacuum and lube oil low pressure There are 4 vacuum switches mounted in the tripping device for condenser low vacuum and 7 pressure switches in the tripping device for lube oil low pressure.
2.1
Signal output from tripping device for condenser low vacuum The vacuum switch PSB1 is actuated to output the alarm signal while the condenser vacuum becomes lower (i.e. the pressure in condenser P≥14.7kPa). Three vacuum switches PSB2～PSB4 are actuated to output the signal to the ETS for simultaneous alarm while the condenser vacuum becomes too low ( i.e. the pressure in condenser P≥ 19.7kPa).
2.2
Signal output from tripping device for lube oil low pressure The pressure switch PSA1 is reset to output the alarm signal while the oil pressure in lube line P ≤0.049MPa. Meantime the pressure switch PSA2 is also reset to output the signal for automatic starting the AC lube oil pump. The Pressure switch PSA3 is reset to output the signal for automatic staring the DC emergency oil pump while the oil pressure in lube line P≤0.0392MPa. Meantime three pressure switches PSA4～PSA6 are also reset to output the signal to the ETS for simultaneous alarm. It’s unavoidable for the turbine to come into the turning status after idling during shut-down. So if the oil pressure in lube line continuously falls down to P ≤ 0.0294MPa,the pressure switch PSA7 will be reset to output the signal for turning stop and for alarm at same time.
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3
Logic control of two oil pumps for main oil reservoir The turbine oil in protection system necessary for operation of steam turbine is supplied directly by the main oil pump mounted on the same shaft with turbine. The lube oil is supplied by the main oil pump through the oil injector. There are two oil pumps on the main oil reservoir. The AC lube oil pump is used to supply the oil for latching-on of the emergency tripping device during start-up of unit, as well as to supply the lube oil to the bearings, turning gear and oil jacking device during start-up and shut-down of unit instead of the oil injector at outlet of main oil pump, or to supply the lube oil to the above mentioned areas with the oil injector at outlet of main oil pump in parallel while the oil pressure in lube line P ≤0.049MPa during operation of unit. The DC lube oil pump is used to supply lube oil to all bearings of unit with the AC lube oil pump together while the oil pressure in lube line P ≤0.0392MPa (at this moment the unit has received the shut-down signal) or supply lube oil to all bearings of unit independently while the AC lube oil pump is out of work due to trouble, thus to make the unit coming into turning status after idling.
3.1
Logic control of AC lube oil pump 3.1.1 Automatic mode There is a “Auto/Manual” selection pushbutton for AC lube oil pump in the DCS system and mounted on the block control panel in central control room. In case the pushbutton is selected in “Auto” mode, the AC lube oil pump will be put into operation automatically while the oil pressure at outlet of the main oil pump falls from the normal value down to P ≤1.8MPa, or the oil pressure in lube line falls down to P ≤0.049MPa, or the speed of turbine falls down to n ≤2850 r/min during operation of unit. Unless the electric failure happens with its motor, the AV lube oil pump will keep operation after automatic starting until change- over to the “Manual” mode. And only in this case the pump can be stopped with the “stop” pushbutton on UCP. There are an oil draining solenoid valve 25YV and a pressure switch PSA2 for simultaneous test of AC lube oil pump mounted after the orifice in sampling pipe for lube oil pressure of the lube oil low pressure tripping device. After pressing down this simultaneous test pushbutton, the solenoid valve 25YV is energized to drain the oil , then the pressure switch PSA2 is reset to start the AC lube oil pump automatically through the contact while the oil pressure falls down to P ≤0.049MPa.
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3.1.2 Manual mode In case the pushbutton in DCS is selected in “Manual” mode it’s possible to start or stop the AC lube oil pump any time by means of the start/stop pushbutton in DCS. The requirement for regular test of this pump can be also met by this mode. 3.1.3 Signal The DCS is provided with the signal lights for “Auto” mode, start and stop of this pump. Also the alarm signal will be sent out while any electric trouble happens with the motor 301M of this pump. 3.2
Control logic of DC emergency oil pump The DC emergency oil pump is put into operation only while the failure happens with the turbine. The DCS is provided with only the pushbuttons for start, stop and simultaneous test for this pump instead of the “Auto/Manual” mode selection pushbutton. In addition, the signal light for “start” and “stop” of this pump must be provided. The emergency oil pump will start automatically while one of the following situations occurs during operation of unit: a)The AC lube oil pump fails to automatic start due to under- voltage of control power source for its motor or electric failure occurring with its motor while the oil pressure in lube line falls down to P ≤0.049MPa; b) There are an oil draining solenoid valve 26YV and a pressure switch PSA3 for simultaneous test of DC emergency oil pump mounted after the orifice in sampling pipe for lube oil pressure of the lube oil low pressure tripping device. After pressing down this simultaneous test pushbutton, the solenoid valve 26YV is energized to drain the oil , then the pressure switch PSA3 is reset to start the DC emergency oil pump automatically through the contact while the oil pressure falls down to P ≤0.0392MPa. The DC emergency oil pump is un-necessary to be provided with any protection measures, because it’s the last supplier of lube oil to the unit and to prevent the bearing pad of unit from burning out will be much valuable comparing with protecting the relative cheaper DC motor. For this reason only an alarm signal will be sent out while electric failure happens with the motor 302M of pump.
4
Control logic of oil jacking pump There are two oil pumps for the oil jacking device, one of which is for stand-by while the other one is being in work. The oil jacking pump is used to establish high pressure to force the shaft journal
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lifting-up during start-up and shut-down on unit, thus to create the necessary condition for turning the unit.
4.1
Automatic mode The DCS is provided with a selection pushbutton “Auto/Manual” for 1#～2# oil jacking pumps. In case this pushbutton is selected in “Auto” mode, both pumps are under automatic control. The “Auto” mode is used during shut-down of unit. As soon as the turbine suffers tripping, its speed falls from 3000r/min down to 1200r/min and the 1# oil jacking pump receives the start signal first and time counting begins at same moment. If the oil pressure at inlet of 1# oil jacking pump is normal(P≥0.1MPa), the pump will start automatically. If 1# oil jacking pump fails to start within 5 sec. due to electric trouble, 2# oil jacking pump will start automatically on the premise of the oil pressure at its inlet normal (P≥ 0.1MPa). In addition, if 1# oil jacking pump becomes out-of work due to electric trouble during operation or due to oil pressure at its outlet lower than setting value(P≥0.1MPa)during operation, 2# oil jacking pump will also start automatically on the premise of the oil pressure at its inlet normal and vice versa. This kind of logic can meet the requirement for both pumps serve for stand-by each other. After automatic starting, the oil jacking pumps will keep operation. They will stop automatically only when the speed of turbine becomes higher than 1200r/min, or oil pressure at outlet of pump is lower than setting value, or electric trouble happens with its motor. Alternately, they will stop by means of the “Stop” pushbutton after change-over to the “Manual” mode.
4.2
Manual mode In case the pushbutton for oil jacking pump is selected in “Manual” mode, it’s possible to start or stop the oil jacking pump ant time as required by means of the start/stop pushbuttons in DCS. One of these two oil jacking pumps is able to start while the oil pressure at its inlet is normal and the other pump is not in working status. Any of these two pumps is able to start by means of pushbutton only when the other pump being in operation is out of work. It’s not allowed to put two oil jacking pumps into operation at same time.
4.3
Signal The DCS is provided with the signal lights for “Auto” mode, start and stop of these two oil jacking pumps. The alarm signal will be sent out while electric trouble happens with the
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motors 303M, 304M of pumps. The alarm signal will be also sent out while the core of twin-shell oil filter or plate-type oil filter becomes plugging. 5
Logic control of turning gear Before normal turning the lube oil line must work normally(P≥ 0.08MPa). The transmission of turning gear is realized in following way: the motor transmits the movement to the swinging pinion after speed reducing, then the pinion is engaged with the gear rim on the rotor (engagement completed) to rotate the rotor. The procedures of tuning during start-up of the unit are as follows:
a)
Energize the solenoid valve to lead the pressurized oil in for relieving the interlock of swinging oil cylinder first, and moving the swinging cylinder with pinion in direction of the gear rim on rotor then.
b) Start the motor and keep it running while the swinging pinion is engaged with the gear rim on rotor (engagement completed). 5.1 Automatic mode The automatic turning mode is used during shut-down of unit. In case the selection pushbutton “Auto/Manual” for turning gear on the local control panel is selected in “Auto” mode, the above-mentioned two procedures a) and b) will be conducted automatically while the oil pressure in lube line and oil jacking line is normal and the speed of turbine falls from the rated value down to zero (n ≤2r/min,contact signal sent by ESI). Namely energize the solenoid valve first, start the motor for tuning after 30 sec. then. The purpose of time delay is to ensure sufficient time for swinging pinion to complete the engagement with the gear rim on rotor. The motor for turning will keep running while the turning gear completes engagement in place (the solenoid valve is de-energized at this moment). The motor for turning will stop automatically while the oil pressure in lube line is too low (P ≤0.0294MPa) or electric trouble happens with the motor. 5.2 Manual mode In case the selection pushbutton “Auto/Manual” for turning gear on the local control panel is selected in “Manual” mode, it’s possible to control start and stop of the turning gear by means of the start and stop pushbuttons on the local control. There are two kinds of manual mode, one of which is realized by the signal of pushbutton “TG start” on the local control panel instead of the zero speed signal
and the other is realized by the
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pushbuttons for “TG in” and “Motor start” respectively. In case the latter manual mode is used, the solenoid valve is energized after pressing down the “TG in” pushbutton, then is de-energized until reaching the “engagement completed” or the “stop” pushbutton is pressed. The motor is able to re-start through pressing the “motor start” pushbutton only after 30 sec. while the oil pressure in oil jacking line is normal.
A motor emergency start pushbutton is provided specially for the possibility to make the unit coming into turning in the emergency status such as the oil pressure in oil jacking line abnormal. In addition, for convenience the local operation can be realized for such pushbuttons and lights as “TG start”, “TG in”, “TG stop”, “motor start”, “motor emergency start” and “disengagement” etc. The “TG stop” pushbutton on the local control panel is able to be effective after pressing, no matter the turning gear is being in “Auto” or “Manual” mode. It’s necessary to press the “TG stop” pushbutton first while the turning cut is required. Then press the “disengagement” pushbutton after falling down the speed of motor of turning gear to have the motor rotating backward for swinging pinion disengagement. Nothing will happen through directly pressing the “disengagement” pushbutton during turning process. The rolling-up of turbine is realized in turning status. When the speed of turbine reaches a certain value, the swinging pinion will be disengaged automatically by the action of increased centrifugal force of gear rim on rotor. The motor of turning gear will stop automatically while the swinging pinion is in the disengagement status. The local control panel is provided the corresponding interface for remote operation of the turning gear (from DCS). 5.3
Signal The local control panel is provided with such signal lights as “Auto mode”, “Turning completed”, “disengagement completed” and “turning on” etc. An alarm signal will be sent out while electric trouble happens with the motor 307M of turning gear.
6
Various pressure signals for steam turbine Various signals for steam pressure and oil pressure at turbine side are shown in the Fig. All measurement instruments for these pressures shall be supplied by the project owner itself.
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0-4 Temperature 1
General The temperature part of the electric monitoring protection system of steam turbine contains the various temperature related measures taken to ensure the normal start-up and operation of turbine proper and its corresponding auxiliaries, as sell as the various temperature measuring points supplied by the turbine manufacturer.
2
Logic control of motor-driven valve for LP exhaust water spray device There is a motor driven valve 401MV provided for LP exhaust water spray device. As required the water comes from the outlet of condensate pump and sprays out of the nozzles in the both LP exhausts at GOV. and GEN. Ends through the motor-driven valve, the duplex screen and the duplex manual throttling valve successively. The duplex screen is provided with the differential pressure transducer for plugging, one of screen is for working and the other for stand-by. Logic control of motor-driven valve of water spray device a) The DCS is provided with a “opening” pushbutton and a “closing” pushbutton for the valve. Both these buttons will become effective only when the “Auto/Manual” selection button for the valve is in the “Manual” position. b) In case the “Auto/Manual” button for the valve is selected to the “Auto” mode, the motor driven valve will fully open automatically while the temperature at any of two measuring points for exhaust steam in LP hood t≥ 80℃. And the valve will be fully closed while the temperature at both measuring points is t ≤65℃. c) There is an interlock between opening and closing of the valve, namely an interlock between rotating forward and backward of the valve driven motor. d) The stop signal for valve opening will be sent out only when the full opening limit switch of the valve is not actuated, or the full closing limit switch is not actuated but the torque limit switch at opening side is actuated, or electric trouble happens with the valve driven motor. e) The stop signal for valve closing will be sent out only when the torque limit switch at closing side is actuated, or electric trouble happens with the valve driven motor. f)
The signal will be sent out by the corresponding limit switch to the DCS system for
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display while the full opening and closing of the valve is completed. g) There is an alarm signal appearing on DCS for display while electric trouble happens with the valve driven motor. 3
Control logic of turbine proper and its auxiliary systems 3.1 Control logic of motor driven valve 402MV before heating steam inlet header for inter-space between two shells of casing a) During cold start, speeding –up and loading of steam turbine, the said valve shall be open according to the temperature difference of casing metal and the differential expansion between HP/IP casing and rotor and closed while the above mentioned temperature difference and differential expansion become stable after warming. So the UCP is provided with only an opening button, a closing button and an opening/closing stop button for the valve. The valve will be open only under such condition that the drain valve of heating steam inlet header for inter-space between two shells of casing has been open already. b) The stop signal for valve closing will be sent out only when the torque limit switch at closing side is actuated, or electric trouble happens with the valve driven motor, or the stop button is pressed. c) The signal will be sent out by the corresponding limit switch to the DCS system for display while the full opening and closing of the valve is completed. A resistance signal will be sent out by a potentiometer to reflect the valve position status while the valve is at the middle position. d) There is an alarm signal appearing on DCS for display while electric trouble happens with the valve driven motor. 3.2 Control logic of pre-warming of casing The pre-warming steam enters into the casing through two motor driven valves in series, the valve 403MV close to the casing is used as block valve and the other one 404MV as throttling valve. When the pre-warming is required, the block valve is fully open automatically by the signal from the DEH and the throttling valve is slowly open by the operator with remote button according to the HP casing metal temperature. In order to stop the pre-warming, the DEH will send out the closing signal to close the block valve and throttling valve at same time. So the UCP is provided with a “Auto/Manual” selection button —— an
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opening button, a closing button and an opening/closing stop button for two motor driven valves respectively. The requirement for temperature raising rate during pre-warming can be met by means of adjusting the reverse warming valve and drain valves at various sections to ensure the temperature difference of casing wall and the differential expansion within the allowable range. There are two control modes for the casing pre-warming: “stop” and “manual in”. See points b), c) and d) in above item 3.1 for the corresponding signals of opening, closing and stop for these two valves. The motor driven throttling valve can be open only after the motor driven block valve is open. 3.2.1
Automatic mode
In case the “Auto/Manual” selection button for motor driven block valve and motor driven throttling valve on the UCP is in “Auto” mode, the opening and closing of the former valve and the closing of the latter valve will be controlled by the signal from the DEH. The opening of the latter valve can not be controlled automatically. 3.2.2 Manual mode In case the “Auto/Manual” selection button for motor driven block valve and motor driven throttling valve on the UCP is in “Manual” mode, the opening of both valve can be controlled to meet the requirement for temperature raising rate and differential expansion during casing pre-warming by means of the opening button, closing button and stop button on the UCP. 3.3 The emergency relieve valve BDV is of the pneumatic closing type and controlled by the air control solenoid valve TBSV. When the pre-inlet valve of 1＃or 2＃ IV is fully open, the corresponding servomotor leaves from full closing position and the valve TBSV is energized to close the valve BDV by the pneumatic force. In case the pre-inlet valve is not in full opening position, the valve TBSV is de-energized to open the valve BDV due to the compressed air source cut. The valve BDV is provided with position switches for opening and closing to send out the signal to DCS for display. 3.4 Control logic of vent valve There is a vent valve VV mounted in the HP exhaust steam pipe to keep vacuum of HP casing with condenser together for preventing the HP casing from overtemperature caused by windage effect during start with IP turbine or operation with lower load.
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The pneumatic solenoid valve VSV to operate the opening/closing of the vent valve VV is controlled by the contact signal of “open VV valve” from the DEH. The VV valve is open while the signal contact is closing and is closed while the contact is open. The following procedures have been realized by the logic of DEH: a) The VV valve is closed during pre-warming and holding period of HP casing. b) The VV valve is open during start with IP turbine and is closed until change-over between HP and IP casings. It should be emphasized that the VV valve for this unit is located downstream the exhaust of HP casing, and shall not be open with closing the GV to prevent the unit from overspeed. 4
Control logic of demisting fan of main oil reservoir
There are two demisting fans mounted on the main oil reservoir, one of which is for normal working and the other one for stand-by. The DCS is provided with start and stop buttons for the demisting fans. The 1# fan shall start and keep operation before the oil system of turbine putting into operation. The other fan is able to start manually while the fan being in operation is out of work due to trouble. The demisting fans are provided with local start and stop lamps. Also an alarm signal will be sent out to UCP and DAS while electric trouble happens with the fan driven motor. 5
Control logic of heater for main oil reservoir
The main oil reservoir is provided with 6 electric heaters which is divided into two groups composed of three heaters for each in three-phase 380V star-connected circuit. The UCP is provided with a start button, a stop button, a power-on button and a power-off button for each group of heaters. In addition, an alarm signal will be sent out to DCS while trouble happened with the heater. The “power-on” lamp turns on while any of three heaters in same group is energized. But the “power-off” lamp turns on only when all three heaters in same group are de-energized. The condition for putting heater into operation is: the oil level in main oil reservoir normal (not in lower level), the AC lube oil pump or the DC emergency oil pump being in work and the oil temperature in oil reservoir low. In order to avoid degradation of turbine oil quality due to overtemperature on surface of heater, the thermal resistance is provided for the surface of heater. The heating process
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will be intercepted while the temperature on surface of heater is ≥140℃. In addition, the heating process will be also intercepted while the oil temperature in oil reservoir is ≥35 ℃, or electric trouble happens with heater (e.g. actuation of protection switch due to overload or short circuit). 6
Various temperature signals of steam turbine
Fig.13～17 show various temperature signals for bearing metal and drain oil from bearings of turbine in detail and illustrate the type and application of thermal element. It should be noted that the Dongfang Steam Turbine Works is responsible only to provide the primary thermal element in its supply scope. The project owner shall be responsible for the primary thermal element including the following transducer in its scope.
0-5 Auxiliaries 1
General The auxiliaries part of electric monitoring protection system for steam turbine contains the control logics for various motor-driven valves, solenoid valves and other motors in draining system, pneumatic system for extraction check valves and HP exhaust check valves and self sealing system of turbine proper.
2
Control logic of pneumatic valves in draining system for turbine proper During start-up, shut-down and operation with lower load, or under abnormal operation condition of turbine, any condensate in turbine proper and piping shall be drained through motor-driven drain valves to avoid rotor bending or components damage caused by the water entering into the casing. There are total 13 motor-driven drain pumps in draining system of turbine, 7 from which are at HP section (501PV～507PV in logic diagram),4 at IP section (508PV～511PV) and 2 at LP section (512PV, 513PV). All these drain valves are controlled by their own air control solenoid valves(501SV ～ 513SV)respectively for opening and closing. The pneumatic actuating system of these drain valves is composed of air control solenoid valve, diaphragm-type actuator, and limit switches for full opening and full closing of valve. The DCS is provided with a “Auto/Manual” selection button, a opening button and a closing button.
2.1 Automatic control mode for pneumatic valves In case the “Auto/Manual” selection button for any drain valve on the DCS is in the “Auto”
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mode, the said drain valve is under automatic control for its opening and closing. In automatic mode, the drain valve will be open while the oil switch of generator changes from closing to opening, because the tripping of oil switch leads to de-energizing of the air control solenoid valve, thus to cut the air source for pneumatic drain valves. In automatic mode, as soon as the load of generator rises to 10%, 20%, 30% of rated value, the DEH will send out signals to energize the air control solenoid valves for HP, IP and LP sections successively for closing the drain valves at these sections by the action of compressed air force. And when the load of generator falls down to 30%, 20%, 10% of rated value, the DEH will send out signals to de-energize the air control solenoid valves for HP, IP and LP sections successively for opening the drain valves at these sections due to air source cutting. 2.2 Manual control mode for pneumatic valves In case the “Auto/Manual” selection button for any drain valve on the DCS is in the “Manual” mode, the said valve is under manual control. In this case the said drain valve can be open or closed by means of the local opening button or closing button for this valve. 3
Control logic of check valves in pneumatic system of extraction and HP exhaust check valves The steam turbine is provided with check valves at all extraction ports with the purpose to avoid overspeed caused by the steam in feedwater heaters returning back into the casing through extraction piping due to pressure reducing during load rejection. And the check valves mounted at HP exhaust are used to avoid the low temperature steam in reheater of boiler returning back to HP casing during hot start and load rejection. There are total 10 check valves (514PV～521PV in logic diagram) at extraction ports and 2 check valves 522PV, 523PV in logic diagram) at HP exhaust. The “free state” of extraction check valve is defined as it can be open while the working medium flows forward and be closed while the working medium flows backward. The DCS is provided with an “Auto/Manual” selection button, a manual opening button and a manual closing button for each check valve. Also the DCS is provided with the corresponding lamps to indicate the check valves being in “Auto” mode. In addition, the DCS is also provided with signal lamps to indicate the extraction check valves being in closing status and two check valves at HP exhaust being in opening status as well as the corresponding alarm signals.
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3.1 Automatic control mode of extraction check valves In case the “Auto/Manual” selection button for extraction check valves on the DCS is in the “Auto” mode, the said check valves are under automatic control for its opening and closing. 3.1.1 Automatic control mode of extraction check valves leading to feedwater heaters There are total 8 extraction check valves leading to feedwater heaters, namely: a)
#1 extraction check valve 514PV leading to #3 HP heater JG3.
b) #2 extraction check valve 515PV leading to #3 HP heater JG2. c)
#3 extraction check valve 516PV leading to #1 HP heater JG1.
d) #4 extraction check valve 517PV, 518PV leading to deaerator (CY and house service steam). e)
#4 extraction check valve 519PV leading to the BFPT.
f)
#5 extraction check valve 520PV leading to #4 LP heater JD4.
g) #6 extraction check valve 521PV leading to #3 LP heater JD3. 3.1.1.1
Any of above mentioned extraction check valves will be open automatically while the following conditions are met at same time:
a)
The corresponding heater (deaerator) has be put into working.
b)
The water level in corresponding heater (deaerator) is normal.
c)
The oil switch of generator didn’t change from closing to opening.
d)
The main stop valve is full open.
3.1.1.2 Any of above mentioned extraction check valves will be closed automatically while one of following conditions is met: a)
The oil switch of generator trips (from closing to opening).
b)
All electric tripping signals are cut or the main stop valve is fully closed.
c)
The water level in corresponding heater (deaerator) is too high.
d)
The corresponding heater (deaerator) in cut manually.
3.1.2 Automatic control mode of extraction check valve for house service and BFPT This is the #4 extraction check valve 519PV for BFPT. 3.1.2.1
The above mentioned extraction check valve will be open automatically
while the following conditions are met at same time: a)
The oil switch of generator didn’t change from closing to opening.
b) The main stop valve is open.
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3.1.2.2
The above mentioned extraction check valve will be closed automatically
while one of following conditions is met a)
The oil switch of generator trips (from closing to opening).
b) All electric tripping signals are cut. c)
The main stop valve in fully closed.
The #4 extraction check valve 519PV for BFPT will be also closed automatically while the tripping signal is sent out by the BFPT. 3.2 Automatic control mode of two HP exhaust check valves In case the “Auto/Manual” selection button on DCS for two HP exhaust check valves is in the “Auto” mode, these two check valves will be under automatic control for opening ( in free state) and closing (forced closing). When the main stop valve is open, two HP exhaust check valves will be open automatically and come into free state. These two check valves will be closed while the mode of start with IP turbine is selected and the change-over of valves is not performed at same time, or all electric tripping signals are cut or the main stop valve is fully closed. 3.3
Manual control mode of check valves
In case the “Auto/Manual” selection button on DCS for any check valve is in the “Manual” mode, the said check valve will be under the manual control for its opening and closing. In this case the said check valve can be open or closed by means of the local opening button or closing button respectively. 4
Control logic of motor-driven block valves in self-sealing system of turbine There are total 10 motor-driven block valves in self-sealing system of turbine, namely the block valve 502MV, regulating valve 504MV and bypass block valve 503MV of auxiliary steam supply in control station for auxiliary gland steam; the block valve 505MV, regulating valve 507MV and bypass block valve 506MV of main steam supply in control station for main gland steam; the overflow regulating valve 508MV and bypass block valve 509MV in control station for gland overflow; as well as the block valve 510MV, regulating valve 511MV of cooling water supply for LP gland steam desuperheater. 4.1 Automatic control mode of motor- driven block valve The DCS is provided with the “Auto/Manual” selection button only for the auxiliary steam supply valve in control station for auxiliary gland steam. In case the selection button is in
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the “Auto” mode, the said valve will be under automatic control. Under various starting conditions of turbine, the auxiliary gland steam supply valve will be open automatically while the steam temperature before the said valve is normal (210℃ ≤t≤260℃), or the oil switch of generator changes from closing to opening and the steam temperature before auxiliary gland steam supply valve t≥260℃ at same time. The said valve will be closed automatically while the oil switch of generator changes from closing to opening and the steam temperature before auxiliary gland steam supply valve t<210℃ at same time. 4.2 Manual control mode of motor-driven block valves In case the “Auto/Manual “ selection button on DCS for auxiliary gland steam supply valve is in the “Manual” mode, the said valve will be under manual control. The rest 9 motor-driven valves in self-sealing system of turbine can be controlled only manually. The auxiliary gland steam supply valve can be controlled for full opening or full closing by means of the corresponding opening button or closing button on the DCS respectively. The rest 9 motor-driven valves in self-sealing system are provided with not only the opening button and the closing button, but also the stop button, so the opening of these valves can be controlled. The control logic for 10 motor-driven valves in self-sealing system are as follows: a) There is the interlock between opening and closing provided to these valves, i e. between forward and backward rotating of the valve driven motor. b) In case the stop button is not pressed, the signal for opening stop of the valve will be sent out while the full opening limit switch of the valve is actuated, or the full closing limit switch of the valve is not actuated but the torque limit switch at opening side is actuated, or electric trouble happens with the valve driven motor. c)
In case the stop button is not pressed, the signal for closing stop of the valve will be sent out while the torque limit switch at closing side is actuated, or electric trouble happens with the valve driven motor.
d) The DCS is provided with signal lamps corresponding to the “opening/closing completed” and “Auto mode” of the valve. The indication lamps for opening and closing of the valve are controlled by the position switch on corresponding motor-driven valve. e) There will be alarm signal output on DCS while electric trouble happens with the
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valve driven motor. 4.3 Control logic of valve driven motors See the drawing and information supplied by the supplier with equipment together for concrete requirement of control for motor-driven regulating valves. 5
Control logic of motors in gland system Each steam turbine is provided with two gland fans, one of which is for stand-by while the other one is being working. The control logic for both fans is same as follows: a)
The DCS is provided with the corresponding “Auto/Manual” selection button, a start button and a stop button.
b)
In “Auto“ mode the stop signal of one fan just is the start signal of the other fan.
c)
Both fans will start at same time while the pressure in inlet manifold of fans P≥ 5kPa.
d)
In “Auto” mode the stop signal will be sent out only while electric trouble happens with the fan driven motor but in “Manual” mode the stop signal will be sent out also by means of the stop button.
e)
The DCS is provided with the signal lamps corresponding to the start, stop and “Auto” mode of fans.
f)
There will be alarm signal output on DCS while electric trouble happens with the fan driven motors. 0-6
1
ETS
General The Emergency Trip System (ETS) of steam turbine is able to start automatically the closing loop while trouble occurring with turbine, tripping occurring with generator and tripping occurring with main fuel of boiler, thus to fast close the steam inlet valves( main stop valves and control valves). The ETS is composed of mechanical-hydraulic and electric-hydraulic parts. That means the trouble can be detected in mechanical mode and electric mode. But the closing of steam inlet valves is controlled by the hydraulic control and protection system finally.
2
Mechanical-hydraulic emergency tripping The emergency governor is a mechanical detector for overspeed trouble. In case the speed of turbine reaches n≥3300r/min, a stop ring will be flies out by the action of centrifugal force to actuate the emergency tripping device. The emergency tripping device changes
- 30 -
the moving direction of the trip valve in tripping isolation valve group to drain the HP control oil. After the HP control oil is drained, the overspeed limiting control oil is also drained through the check valve. As a result the control oil pressure in dump valves for servomotors of steam inlet valves disappears and the dump valves are open. Then the pressure oil in both upper and lower chambers of servomotors is connected to the drain port through the opened dump valves to fast close the steam inlet valves. After full closing of the main stop valves the limiting switch signal will be sent out to the check valves through electric control loop. 3
Electric-hydraulic emergency tripping This is an electric mode to detect the trouble occurring with turbine, the tripping occurring with generator and the tripping occurring with main fuel of boiler and also to send out the electric tripping signal to the mechanical tripping electric magnet 3YV at same time. As soon as the electric tripping signal is sent to the mechanical tripping electric magnet 3YV, the latte will be energized to actuate the emergency tripping device through linkage mechanism. The following process will be performed as same as described in above point 2. Although the extraction check valves can be closed by the signal after full closing of the main stop valve, various electric tripping signals will be sent to the above solenoid valves and the check valves at same time to fast close the latter valves.
4
Electric tripping signals The electric tripping signals of ETS for the steam turbine are as follows: a) Manual stop button in center control room. b) Overspeed: In case the speed of turbine rises to 3300r/min and above, the overspeed relays in overspeed monitoring channels of ETS are actuated and the tripping signal is sent out after processing by the ETS in 2 out of 3 logic through the output contact. c) Lube oil low pressure: In case the oil pressure in lube line P≤0.0392MPa (which is the setting value for pressure switch as mentioned above), three pressure switches PSA4～PSA6 in
lube oil low pressure tripping device will be reset and three
normal-closed contacts will send out the tripping signal after processing by the ETS in 2 out of 3 logic. d) Fire-resistant oil low pressure: In case the oil pressure in fire-resistant oil line is too lower, three pressure switches in resistant oil manifold supplied by the DEH
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manufacturer will be reset and three normal-closed contacts will send out the tripping signal after processing by the ETS in 2 out of 3 logic. e) Condenser low vacuum: In case the pressure in condenser P≥19.7kPa, three vacuum switches P≥19.7kPa in condenser low vacuum tripping device are actuated and
three normal-open contacts will send out the tripping signal after processing
by the ETS in 2 out of 3 logic. f) Axial displacement too big: In case the shaft displacement related to thrust bearing increases (≥1.2mm or ≤-1.65mm. It should be noted that the working pads of thrust bearing in this turbine are mounted at generator end, so the axial displacement will be positive while the shaft moves in the direction of generator and be negative while the shaft moves in the direction of head of unit), the axial displacement emergency relay in dual- channel axial displacement monitor will be closed after processing in TSI in “AND” logic and the normal-open contacts will be used as tripping signal. g) The steam turbine will suffer tripping by trouble with main fuel of boiler and trouble with generator, the former signal will be supplied by the boiler manufacturer and the latter signal by the generator manufacturer. h) Shaft vibration too high: The TSI will send out the shaft vibration too high signal while the shaft vibration in X axis at any of 1#～6＃ bearings is too high(≥ 0.25mm) or the shaft vibration in Y axis at any of 1#～6＃ bearings is too high(≥ 0.25mm). Above mentioned combination logic has conducted in the TSI and a contact signal is sent out by the TSI to the ETS for turbine tripping. i)
DEH tripping: This is the turbine tripping signal supplied by the DEH manufacturer and contains the turbine overspeed monitored by DEH, DEH speed signal trouble and etc.. It’s used to output the shut-down contact signal for turbine tripping.
j)
Other signals for shut-down of unit
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Section2
Manual of emergency tripping device of steam turbine
General Introduction The emergency tripping system receives the alarm signal or tripping signal from TSI system or other system of steam turboset to conduct logical process and send alarm signal of indicating lamp or tripping signal of steam turbine. Duplex PLCs (programmable controller) are selected by us to conduct logical process so as to facilitate the usage and reliable operation. The duplex PLCs work at the same time, any action can send alarm signal. In case the trouble happens with any PlC, it can send alarm signal of itself and switch-off its tripping logical output, another is still at normal work. This device can communicate with other system so as to meet the automation requirement of power plant. 0-1 Device description 1. ETS device includes one control cabinet. The series programmable controller (PLC) made by Siemens Company S7-300, German is substituted for traditional relay logic to realize the inner logic. In order to improve the reliability and safety of ETS device, we adopt the duplex PLC. The hardware distribution is as follows: PLC Processor PLC input module PLC input module PLC output module PLC power supply 2. Environment conditions
TSX P57 102M TSX DEY 08D2 TSX DEY 16D2 TSX DSY 16T2 TSX PSY 2600M
Operating environment:5℃～55℃ Relative humidity:35%～85%RH (without dewing) Vibration:2.0G (10～55Hz) Without caustic gas and conductive dust. 3. Stand-by batteries One groove used for putting the battery is equipped on battery module to supply power for inner RAM of processor and protect the data after the PLC power-off. Such battery is supplied with CPU module. While putting through the power source, CPU module monitors the status of battery. In case the red alarm signal on BAT indicating lamp flashes during occurring failure, it shall be replaced at once. The battery is replaced during power-on or within a short time of
- 33 -
power-off. Otherwise the data in RAM will be lost after removing the battery for 10min. Caution: In order to protect the device, the battery shall be replaced every year. 4. Brief description of control cabinet The control cabinet diagram refers to the first sheet of M913-042000A please. 0-2 Working principle 1. The duplex PLCs of ETS device works at the same time. The signal from site input to A
PLC and B PLC of the device, and the corresponding output signal are sent out after auto processing by inner logic. Give an example of “steam turbine over-speed”, the electric tripping signal inputs to PLC A and PLC B of device to process, and the tripping signal outputs at the same time. 2. In case the trouble happens with any of PLC A/B, the alarm signal of the said PLC can be sent to cut the tripping output contact automatically, and the other PLC will keep normal working. The logic scheme of duplex PLC working/tripping is shown in Fig. 0-2-1. tripping A PLC A Normal
tripping A Tripping tripping B
tripping B PLC B Normal Figure 0-2-1 Duplex PLC working principle diagram
3. Two ways power source switching-over loop are equipped for ETS device. In case the trouble happens with one power source, it can continue working by means of switching over to another power source loop automatically. In case the trouble happens with the both master/slave power source, one AC power source power-off alarm signal is sent. +24V power source is provided for whole device after two QUINT-PS power source with redundance. Such power sources together with TSX PLP 01 failure all inputs one +24V power source power-off alarm signal. 4. This device shall be deigned according to the logic required by customer. 5. All input/output and wiring diagram of this device see from drawing0-2-2 to drawing 0-2-5. The control logical scheme of device sees drawing from 0-2-6 to drawing 0-2-7.
- 34 -
Tripping 1 for electrical over-speed
D1 terminal row Tripping 2 for electrical over-speed
field input signal Tripping for generator failure
Tripping 3 for electrical over-speed
Tripping for boiler failure Tripping for shaft vibration big
Tripping by DEH
Manual tripping
Tripping
Tripping stand-by 1
for axial displacement big Tripping stand-by 2
Tripping for condenser vacuum low. Tripping stand-by 3
Tripping 2 for condenser vacuum low
Standby terminal
Tripping 3 for condenser vacuum low Test for HP tripping solenoid valve 1
Tripping 1 for lube oil pressure low Test for HP tripping solenoid valve 2
Tripping 2 for lube oil pressure low
Test for HP tripping solenoid valve 3
Tripping 3 for lube oil pressure low Test for HP tripping solenoid valve 3
Tripping 2 for EH oil pressure
Reset signal
Tripping 3 for EH oil pressure
Figure 0-2-2
Terminal wiring diagram (1)
Standby terminal
Tripping 1 for EH oil pressure
D1 Terminal row D1 Terminal row master power source master power source slave power source slave power source output power source for master breaker output power source for master breaker output power source for slave breaker output power source for slave breaker Terminal for protection Lighting power source Input power source for interference suppressor Lighting power source Input power source for interference suppressor PLC working power source (terminal for protection) PLC working power source (terminal for protection) PLC working power source (terminal for protection) PLC working power source (terminal for protection) PLC working power source (terminal for protection) PLC working power source (terminal for protection)
24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection) 24V power source (terminal for protection)
(+) (+) (+) (+) (+) (+) (+) (+) (+) (+) (+) (+) (+) (+) (+) (+) (+)
PLC working power source PLC working power source PLC working power source PLC working power source PLC working power source PLC working power source
Figure 0-2-3 Terminal wiring diagram (2)
Tripping output 1 electrical over-speed
D2 Terminal row Tripping signal output
Tripping output 2 electrical over-speed
for
for
Tripping output 1 for generator failure Tripping 1 for shaft vibration Tripping output 2 for generator failure Tripping output 1 for boiler failure
Tripping 2 for shaft vibration
Tripping output 2 for boiler failure
Tripping output 1 for DEH
Tripping output 2 for DEH
Manual tripping output 1
Manual tripping output 2
Tripping output displacement big
1
for
axial
Tripping output displacement big
2
for
axial Tripping stand-by 1, output 1
Tripping output 1 for condenser vacuum low Tripping stand-by 1, output 1 Tripping output 2 for condenser vacuum low Tripping stand-by 2, output 1 Tripping output 1 for lube oil pressure low Tripping output 2 for lube oil pressure low Tripping output 1 for EH oil pressure low Tripping output 2 for EH oil pressure low
Tripping stand-by 2, output 1
Tripping stand-by 3, output 1
Tripping stand-by 3, output 1
stand-by terminal
Figure 0-2-4 Terminal wiring diagram (3)
Tripping output
Test for HP tripping
Slave power source power-off alarm output
Test for HP tripping solenoid valve 2
Master/slave power source power-off alarm output 1 24VDC power-off alarm
Test for HP tripping solenoid valve 3 Test for HP tripping solenoid valve 4 Test for HP tripping solenoid valve 4
stand-by terminal
Tripping signal to DEH
Tripping output 1
Tripping output 2
Tripping output 3
Alarm Output Tripping output 4 PLC A failure alarm output
PLC B failure alarm output
stand-by terminal
Master power supply power-off alarm output
Figure 0-2-5 Terminal wiring diagram (4)
Signal for generator failure Reset signal output The first way tripping output of generator failure The second way tripping output of generator failure
reset button reset signal
reset signal output
Tripping signal of boiler failure Reset signal output The first way tripping output of boiler failure The second way tripping output of boiler failure
DEH tripping signal Reset signal output The first way tripping output of DEH The second way tripping output of
tripping stand-by signal 1 reset signal output
Manual tripping signal Reset signal output
The first way of manual tripping output The second way of manual tripping output
2 out of 3
Tripping signal for axial displacement big Reset signal output
1Tripping signal 1 for condenser vacuum low 2Tripping signal 2 for condenser vacuum low 3Tripping signal 2 for condenser vacuum low
The first way tripping output of axial displacement big The second way tripping output of axial displacement big
2 out of 3
2Tripping signal 2 for lube oil pressure low 3Tripping signal 3 for lube oil pressure low
tripping stand-by signal 1 reset signal output
The first way tripping of shaft vibration big The second way tripping of shaft vibration big
tripping stand-by 1, the first way of tripping output tripping stand-by 1, the second way of tripping output
Tripping signal to DEH
tripping stand-by 2, the first way of tripping output tripping stand-by 2, the second way of tripping output
tripping stand-by signal 1 reset signal output
3Tripping signal 3 for EH oil pressure low
2 out of 3
1Tripping signal 1 for EH oil pressure low
Reset signal output
Note: The logic of PLC A is same as that of PLC B.
Reset signal output
The first way tripping output for EH oil pressure low The second way tripping output for EH oil pressure low
Indicates the indicator light of this machine Indicates the output contact Indicates the output contact
3Tripping signal 3 for electrical over-speed
2 out of 3
1Tripping signal 1 for electrical over-speed 2Tripping signal 2 for electrical over-speed
Tripping signal to DEH Tripping output 1
Tripping output 3 tripping stand-by 3, the first way of tripping output tripping stand-by 3, the second way of tripping output
The first way tripping output of lube oil pressure low The second way tripping output of lube oil pressure low
2Tripping signal 2 for EH oil pressure low
tripping A
Tripping output 2 Reset signal output
The first way tripping output of condenser vacuum low The second way tripping output of condenser vacuum low 1Tripping signal 1 for lube oil pressure low
Tripping signal for shaft vibration big Reset signal output
Reset signal output
The first way tripping output of electrical over-speed The second way tripping output of electrical over-speed
Figure 0-2-6 Logic diagram (1)
Tripping output 4
Test output (often close) for HP tripping solenoid valve 1 Test output (often close) for HP tripping solenoid valve 2 Test output (often close) for HP tripping solenoid valve 3 Test output (often close) for HP tripping solenoid valve 4
Test signal for HP tripping solenoid valve1 Test signal for HP tripping solenoid 2 Test signal for HP tripping solenoid 3 Test signal for HP tripping solenoid valve 4
Note: The logic of PLC A is same as that of PLC B.
Figure 0-2-7 Logical diagram 0-3 1
2
Function
Power-on Switch-on the master, slave power source breaker, the indicating lamp is on and the voltage indicating is normal. Tripping: The tripping signal shall be sent by PLC while the following items occur. The steam turbine will trip for shut-down. a) b) c) d) e) f) g) h) i) j) … m)
Steam turbine over-speed (2 out of 3) Axial displacement EH oil pressure too low (2 out of 3) Condenser vacuum too low (2 out of 3) Lube oil pressure too low (2 out of 3) Steam turbine vibration too high; Tripping by DEH; Generator tripping; Main fuel of boiler; Manual tripping; Stand-by 1 for tripping … Stand-by 3 for tripping
0-4 Power-on self-checking Connect two lines of 220VAC power source to the input of master, slave breaker for ETS device, and then switch-on breaker, the indicating of voltage meter on device panel is correct, and the indicating lamp of master, slave power source is on, the +24V power source indicating of device is normal. At this time, the PLC starts self-checking. The “RUN” indicating lamp of CPU is on after finishing self-checking. The ETS device can be put into operation in site. 0-5 Maintenance This device is full controlled by computer. The complete check and test shall be performed before putting into operation. It can be put into operation after free of troubles. The check and test include the following: a)
Check whether the master, slave power source work normally.
b)
The anti-interference suppresser is equipped to prevent the strong interference signal input into control cabinet. Care for whether the indicating of voltage meter on device cabinet is correct. The power source distribution of control cabinet sees 0-5-1 scheme;
c)
Remove the dust in control cabinet;
d)
Replace the failed components.
Master power source of Breaker
Slave power source of Breaker
To Rack Light and Fan
Anti-interference suppresser K
Figure 0-5-1 Wiring scheme of power source
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section3
Instruction on automatic operation device for turning gear 0-1
Overview
The automatic operation device of turning gear is used to provide an operation loop for realizing the manual or automatic turning of unit. In automatic turning mode the device receives the zero speed signal from TSI system. The programmable logic controller (PLC) is adopted for the device to realize the logic control. In order to improve the start-up feature during putting into operation of the turning gear the device is also provided with a soft start-stop block, which is able to stop turning automatically while the oil-jacking pump is out-of- work, lube oil pressure is lower than certain value, or the turning current is too higher.
0-2 Device Description The automatic operation device of turning gear contains a control cabinet, where the internal logic is realized by the PLC of TSX serial from Schneider Atomization Company instead of the traditional relay logic.
1
PLC input/output Input power supply: AC100～AC240V ca.50VA Input signal voltage: DC24V Input:
16(with common contact supplied by TSX DEY 16D2 block) 16 (with common contact supplied by TSX DEY 16D2 block)
Output: 16 (with common contact supplied by TSX DSY 16R5 block) 16 (with common contact supplied by TSX DSY 16T2 block) 2 Working environment Ambient temperature: Relative humidity:
5～55℃
30～95%RH（without dewing）
Anti-vibration capability: In accordance to IEC 68-2-6, Fc test. 3 Hardware feature Control power supply: AV 220V single-phase 50Hz 4 Feature of Softstart: 4.1 The soft start-stop block “Softstart” is able to control the start-stop of AC three-phase motor and provide the start-stop parameters. 4.2 “Regulation-display” option There are terminal marks on the panel for 12 control loops Terminal
Application
1, 2, 3
Power supply L, N, PE
4, 5, 6
Start-stop loop
7, 8
Fault signal loop - 42 -
9, 10
Start-up completion indication relay loop (bypass)
11, 12
Connection to external current transformer
Status indication
Application
ON
Green
Ready
TOP OF RAMP
Green
Normal operation
EXTERNAL FAULT
Red
Motor and software missing
GENERAL FAULT
Red
Power supply side missing
The Softstart is provided with 3 rotary setting switches and a two-position toggle switch. Start-up curve: Set the raising time of voltage during start-up with 16 adjustable steps in range of 1-30 sec. Shut-down curve: Set the falling speed of voltage during start-up with 16 adjustable steps in range of 0-30 sec. The immediate stop can be realized while choosing the 0 sec. Initial voltage/limiting voltage: Set the initial voltage level for start-up curve and the final voltage level for shut-down curve. In case the current transformer T2 is connected to the terminals 11 and 12, set the limiting voltage with the same rotary switch as that for initial voltage setting. 5 Description of control cabinet The control cabinet is shown in Fig. 0-2-1.
- 43 -
Fig.0-2-1 1-Voltmeter;
Control cabinet scheme
2-Amperemeter;
3-Turning indication;
4-“Disengagement
completed” indication; 5-“engagement completed” indication; 6-“Oil jacking pressure normal” indication; 7-“lube oil pressure normal/lower” indication; 8-“Turning admission” indication; 9-“Motor stop” indication; 10-Power lamp; 11-“Turning admission” selection switch; 12-“Local control selection switch; 13-“Manual/Auto” selection switch; 14-Lamp test pushbutton; 16-“Inching / in” pushbutton; 18-“Test/bypass” pushbutton;
15-“SV action” pushbutton; 17-“TG stop” pushbutton; 19- Turning-off pushbutto
0-3
Working Principle
1. The control scheme of turning gear is shown in Fig.0-3-1, the circuit scheme of control loop and main loop are shown in Fig.0-3-2, and Fig.0-3-3 respectively and the control logic scheme is shown in Fig.0-3-4.
control system(PL C)
Softstart
AC motor
reducer
turbine turning gear
AC motor Fig. 0-3-1 control scheme of automatic turning gear
The three-phase power supply of turning gear is connected to the Softstart of motor through the AC contactor in control loop. Then the output of Softstart of motor is sent to the motor to drive the turning gear. According to the control requirement, the PLC controls the solenoid valve for oil entering/draining in hydraulic mechanism and the forward/backward rotation of the motor driving the turning gear. 2. Features of device The device is able to realize such functions as automatic turning at zero speed, Manual auto-turning, emergency turning, low oil pressure protection and remote control etc. Since the imported PLC is adopted as the logic control component in the device and all control logics are established by PLC software (ladder logic diagram), the control is very flexible and the function is powerful. Also the imported ABB Softstart is used for the drive motor, so as to reduce the attack to the motor and turning gear of turbine, as well as to put the turning gear into operation smoothly and accurately. The wiring of the device is quite clear and easy and convenient for maintenance. See the corresponding system logic diagram and the PLC ladder logic diagram for concrete control logic in detail. 3. Working principle According to the requirement of system logic for turning gear, the control cabinet of automatic operation device for turning gear shall receive the effective signal from the contact for “oil jacking pressure normal” and ‘lube oil pressure normal” to meet the external “turning admission” conditions, otherwise the control cabinet should reject to start the drive motor of turning gear. In order to proper put the turning gear into operation, the brief explanation is given for related operation and logic relationship of three turning modes during start-up hereafter. a) Automatic turning at zero speed As soon as the TSI sends out the zero speed signal to the control cabinet for turning after meeting the external “turning admission” conditions and selecting the automatic turning mode, the PLC in the control cabinet will energize the solenoid valve automatically after confirming the receiving of zero speed signal (usually the stable zero speed signal will be confirmed automatically with delay of about 30 sec.
by the system after receiving), so as to make the turning gear of turbine engaged through hydraulic actuation mechanism. After 30 sec. while the solenoid valve is energized, the PLC in control cabinet for turning begins to check whether the “engagement completed” signal has been received. In case the “engagement completed” signal has not been received, the motor for turning will periodically turn forward in short time and in small steps through the Softstart to facilitate engagement between gears. In case the “engagement completed” signal has been received, the motor will start automatically and keep operation for turning. In case the “engagement completed” signal still has not been received after small moving the motor twice with above mentioned method, the motor for turning will be forced to start, then the solenoid valve will automatically de-energized after motor running for 10 sec. to complete the automatic putting into operation of the turning gear. As soon as pressing down the “TG STOP” pushbutton at any time, the motor for turning will stop. The “TG STOP” pushbutton is an alternative one while the “engagement completed” signal is effective to prevent the motor for turning from automatic start due to not disengagement or the “engagement completed” signal still existing while relieving the “TG STOP” pushbutton. b) Manual auto-turning mode The working principle in manual auto-turning mode is similar as that mentioned above with the exception of a serial operation to be done manually. First of all the external “turning admission” conditions shall be met. Then select the manual turning mode and press down the “SV ACTION” pushbutton to complete the engagement of turning gear through hydraulic actuation mechanism. In case the control device for turning has received the “engagement completed” signal, it will start the motor for turning automatically and de-energize the solenoid valve after 10 sec. In case the control device for turning has not received the “engagement completed” signal, it will force the motor for turning to start. As soon as pressing down the “TG STOP” pushbutton at any time, the motor for turning will stop. The “TG STOP” pushbutton is an alternative one while the “engagement completed” signal is effective to prevent the motor for turning from automatic start due to not disengagement or the “engagement completed” signal still existing while relieving the “TG STOP” pushbutton. c) Emergency turning mode The emergency turning mode has to be used to ensure the rotor of turbine rotating while the external condition for “turning admission” is not met yet, e.g. lube oil pressure low, oil jacking pressure abnormal, or other electric fault existing. But this mode shall be used very attentively, because the additional wear of damage will occur with bearing pad in this case. As soon as pressing down the “TEST AND BYPASS” pushbutton any time in manual turning mode, all safety protection functions for the motor will be lost. In case of pressing down the “INCHING AND IN” pushbutton, the motor for turning will directly start. Naturally, it’s also possible to try to complete the engagement of turning gear by means of pressing down the “SV ACTION” pushbutton first. The “TEST AND BYPASS” pushbutton is an alternative one and this function can be removed as necessary by pressing this pushbutton to have the lamp off in normal case. As soon as pressing down the “TG STOP” pushbutton at any time, the motor for turning will stop. Meantime the “TEST AND BYPASS” Function will lost automatically and the lamp will be off.
Fig.0-3-2
Control loop circuit scheme
Fig.0-3-3 Main loop circuit scheme 4. It’s possible to realize remote control for the turning operation device. All wiring for remote control has been connected to the terminal bar. The various outputs have been also connected to the corresponding terminals and can be led out from the terminal bar by the customer according to the concrete situation. There is an interlock between local control cabinet and remote operation, only one of them could come into action any time. The selection switch 12 is used for control priority selection. The local control becomes effective and the remote control becomes non-effective while the switch is in “LOCAL CONTROL” position. The remote control becomes effective and the local control becomes non-effective while the switch is in “REMOTE CONTROL” position (See Fig. 0-3-4 for logic control ladder diagram).
0-4 TEST 1. Power-on test Connect the power supply of AC380V to the terminal bar and close the breaker QF 1 and MS450. The putting into operation and on-line test can be conducted on site while the power indication lamp on the panel turns on and the indication of voltmeter on the panel of equipment is proper to show the automatic turning gear has come into normal operation. 2 Check for Softstart The various parameters of Softstart can be properly changed according to the concrete situation of power plant. 3
Local control test Set the selection switch 12 to the “LOCAL CONTROL” position to make the local control effective and the remote control non-effective. 3.1 Lamp test Press down the “Lamp test” pushbutton on the panel to make sure that all lamps shall turn on. And all lamps shall return to their original status while relieving the pushbutton. 3.2 Adjustment and test of turning gear 3.2.1 Manual operation test Set the selection pushbutton “Auto/Manual” to the “Manual” position and turn the key switch to the “TG admission” position. If make sure through check that the “TG ADMISSION” lamp 8, “POWER SUPPLY” lamp 10 and “TG MOTOR STOP” lamp 9 turn on and 380V AC is indicated on the voltmeter, the condition for turning has been met. 3.2.1.1 Solenoid valve action test Bridge the lube oil pressure switches JD9, JD10 and the oil jacking pressure switches JD7, JD8, then press the “SV ACTION” pushbutton 15 to have the “SV ACTION” lamp on. If make sure through check that the voltage 220V AC has been established at the output terminals JD34, JD35 of solenoid valve, 30sec. later the turning contactor KM2 is actuated every 2 sec. to indicate small movement of motor, the contactor KM2 is forced to close after small movement two times, and the motor turns forward, the turning of unit begins. 3.2.1.2
Turning test
Bridge the “engagement completed” limit switches JD3, JD4 before the third forced closing. If the turning contactor KM2 is closed, the “TG RUNNING” lamp 3 turns on and the motor runs forward, the turning begins. 3.2.1.3
“Test and bypass” test
Cut any line from oil jacking pressure switches JD7, JD8 and lube oil pressure switches JD9, JD10 , press the “TEST AND BYPASS” pushbutton 18 first to have the lamp on and press the “INCHING AND IN” pushbutton 16 then. If the turning contactor KM2 is also closed at this time, the “TG RUNNING” lamp turns on and the motor runs forward, the turning begins. 3.2.1.4
Stop test
Press the “TG STOP” pushbutton 17. If the “TG STOP” lamp turns on and the turning contactor KM2 powers off, the shut-down of unit is performed normally. 3.2.1.5
Disengagement test
Press the “TG TRANSFER” pushbutton 19. If the disengagement contactor KM3 is closed and the motor runs backward, the disengagement is performed normally. If bridge the “disengagement completed” switches JD1, JD2 at this moment, the contactor KM3 shall be power-off, the motor stops running backward and the “TG MOTOR STOP” lamp HL9 turns on. 3.2.2 Automatic operation test Set the “Auto/Manual” selection pushbutton on the panel to the “Auto” position and turn the key switch to the “TG ADMISSION” position. If make sure through check that the “TG ADMISSION” lamp 8, “POWER SUPPLY” lamp 10 and “TG MOTOR STOP” lamp 9 turn on, as well as 380V AC is indicated on the voltmeter, the condition for turning has been met. 3.2.2.1 Solenoid valve action test Bridge the oil jacking pressure switches JD7, JD8 and the lube oil pressure switches JD9, JD10, also bridge the zero speed signals JD5, JD6. If make sure through check that the voltage 220V AC has been established at the output terminals JD34, JD35 of solenoid valve, 30sec. later the turning contactor KM2 is actuated every 2 sec. to indicate small movement of motor, the contactor KM2 is forced to close after small movement two times, and the motor turns forward, the turning of unit begins. 3.2.2.2 Turning test Bridge the “engagement completed” switches JD3, JD4 before the third forced closing. If the turning contactor KM2 is closed, the “TG RUNNING” lamp 3 turns on and the motor runs forward, the turning begins. 3.2.2.3 Stop test Press the “TG STOP” pushbutton 17. If the “TG STOP” lamp turns on and the turning contactor KM2 powers off, the shut-down of unit is performed normally. 3.2.2.4 Disengagement test Press the “TG TRANSFER” pushbutton 18 to have the “TG TRANSFER” lamp on. If the disengagement contactor KM3 is closed and the motor runs backward, the disengagement is performed normally. If bridge the “disengagement completed” switches JD1, JD2 at this moment, the contactor KM3 shall be power-off, the motor stops running backward and the “TG MOTOR STOP” lamp HL9 turns on. 3.2.3 Inching operation test Set the selection switch 13 to the middle position, i.e. to the “INCHING” position. Bridge the oil jacking pressure switches JD7, JD8 and the lube oil pressure switches JD9, JD10, then press the “INCHING AND IN” pushbutton 16. At this moment the turning contactor KM2 is closed, the “TG RUNNING” lamp 3 turns on, and the motor turns forward. Thus the inching function can be realized by relieving the pushbutton to have the turning contactor KM2 power-off. 4
Remote control test Set the selection switch 12 to the “REMOTE CONTROL” position. In this case the remote control will become effective and the local control un-effective. 4.1 Lamp test Bridge the remote control “LAMP TEST” switches JD16, JD22 and all lamps on the panel
shall turn on. And all lamps shall return to their original status while removing the bridge wire. 4.2 Adjustment and test of turning gear 4.2.1 Manual operation test Set the remote selection pushbutton to the “Manual” position and bridge the switches JD13andJD22. Then press the “TG remote admission” pushbutton to bridge the switches JD15andJD22. If make sure through check that the “TG ADMISSION” lamp 8, “POWER SUPPLY” lamp 10 and “TG MOTOR STOP” lamp 9 turn on and 380V AC is indicated on the voltmeter, the condition for turning has been met. 4.2.1.1 Solenoid valve action test Bridge the oil jacking pressure switches JD7, JD8 and the lube oil pressure switches JD9, JD10, also bridge the “solenoid valve remote action” switches JD17andJD22. The “SV ACTION” lamp will turn on at this moment. If make sure through check that the voltage 220V AC has been established at the output terminals JD34, JD35 of solenoid valve, 30sec. later the turning contactor KM2 is actuated every 2 sec. to indicate small movement of motor, the contactor KM2 is forced to close after small movement two times, and the motor turns forward, the turning of unit begins. 4.2.1.2 Turning test Bridge the oil jacking pressure switches JD7, JD8 and the lube oil pressure switches JD9, JD10. Then bridge the “engagement completed” switches JD3, JD4 before the third forced closing. If the turning contactor KM2 is closed, the “TG RUNNING” lamp 3 turns on and the motor runs forward, the turning begins. 4.2.1.3 “Test and bypass” test Cut any line from oil jacking pressure switches JD7, JD8 and lube oil pressure switches JD9, JD10 and bridge the “remote test and bypass” switches JD18andJD22 to have the lamps on. Then bridge the “Remote inching and in” switches JD20andJD46. If the turning contactor KM2 is closed at this time, the “TG RUNNING” lamp turns on and the motor runs forward, the turning begins. 4.2.1.4 Stop test Bridge the “TG STOP” switches JD19andJD22. If the “TG STOP” lamp turns on and the turning contactor KM2 is power-off, the shut-down of unit is performed normally. 4.2.1.5 Disengagement test Bridge the “remote disengagement” switches JD21andJD22. If the disengagement contactor KM3 is closed and the motor runs backward, the disengagement is performed normally. If bridge the “disengagement completed” switches JD1, JD2 at this moment, the contactor KM3 shall be power-off, the motor stops running backward and the “TG MOTOR STOP” lamp HL9 turns on. 4.2.2 Automatic operation test Remove all bridge wires and set the remote selection pushbutton on the panel to the “Auto” position to bridge the switches JD14, JD22. Then press the “REMOTE TG ADMISSION” pushbutton to bridge the switches JD15, JD22. If make sure through check that the “TG ADMISSION” lamp 8, “POWER SUPPLY” lamp 10 and “TG MOTOR STOP” lamp 9 turn
on, as well as 380V AC is indicated on the voltmeter, the condition for turning has been met. 4.2.2.1 Solenoid valve action test Bridge the oil jacking pressure switches JD7, JD8 and the lube oil pressure switches JD9, JD10, also bridge the zero speed signals JD5, JD6. If make sure through check after 30 sec. that the voltage 220V AC has been established at the output terminals JD34, JD35 of solenoid valve, another 30sec. later the turning contactor KM2 is actuated every 2 sec. to indicate small movement of motor, the contactor KM2 is forced to close after small movement two times, and the motor turns forward, the turning of unit
begins.
4.2.2.2 Turning test Bridge the “engagement completed” switches JD3, JD4 before the third forced closing. If 30 sec latter the turning contactor KM2 is closed, the “TG RUNNING” lamp 3 turns on and the motor runs forward, the turning begins. 4.2.2.3 Stop test Bridge the “TG STOP” switches JD19andJD22. If the “TG STOP” lamp turns on and the turning contactor KM2 is power-off, the shut-down of unit is performed normally. 4.2.2.4 Disengagement test Bridge the “remote disengagement” switches JD21andJD22. The “TG TRANSFER” lamp turns on. If the disengagement contactor KM3 is closed at this moment and the motor runs backward, the disengagement is performed normally. If bridge the “disengagement completed” switches JD1, JD2 at this moment, the contactor KM3 shall be power-off, the motor stops running backward and the “TG MOTOR STOP” lamp HL9 turns on. 4.2.3 Inching operation test Set the remote selection switch to the middle position, i.e. to the “INCHING” position. Bridge the oil jacking pressure switches JD7, JD8 and the lube oil pressure switches JD9, JD10, then press the “INCHING AND IN” pushbutton 16. At this moment the turning contactor KM2 is closed, the “TG RUNNING” lamp 3 turns on, and the motor turns forward. Thus the inching function can be realized by relieving the pushbutton to have the turning contactor KM2 power-off.
0-5
Maintenance
The whole device is controlled by the computer with advanced PLC and Softstart, which shall be subjected to full check and test as follows before putting into operation to confirm their proper function:
a) b) c) d)
Check for proper function of the power supply（AC380V, AC220V）. Check for proper indication of voltmeter on the panel. Clean up the dust in control cabinet Check for proper function of all indication lamps on the panel by means of the “LAMP TEST” pushbutton.
e) Replace the defective element.
section4
Digital Electro-hyraulic (DEH) Control System Specifications 1 Overview
In this chapter the control principle of steam turbine control system and the structural features of 300MW steam turbine generator unit (hereafter referred to as the Unit) are presented. 1-1 Introduction With the progress of computer technology, the Distributed Computer System (DSC) control based on microprocessors is more and more widely used. The emergence of digital electro-hyraulic (DEH) control systems has broken the fact that the adjustment of steam turbine could only be finished by the special steam turbine maintainers who were heat engineers more often than not. Meanwhile, for turbine operators, besides the technological process of the control system, computer knowledge is also very important. Aiming at the new generation 300MW DEH control system that is jointly developed by Dongfang Steam Turbine Works (DFSTW) and FOXBORO, this instruction book presents the basic concepts of steam turbine control system, the configuration of DEH, and the primary functions, operation specifications, and installation and debugging methods of a control system. The book is specially prepared to ensure that the system can be operated safely and reliably. Control System Principle For our D300N steam turbine generator unit, the high-pressure (hereafter referred to as HP) steam admission is controlled by 2 HP stop valves (hereafter referred to as MSV) and 4 HP control valves (hereafter referred to as CV), and the intermidiate-pressure (hereafter referred to as IP) steam admission is controlled by 2 IP stop valves (hereafter referred to as RSV) and 2 IP control valves (hereafter referred to as ICV). All the above 6 admission control valves are driven by hydraulic actuators to meet the requirements of short action time and high positioning accuracy. Normally the working rotation speed of the steam turbine is 3000r/min; however, when the load in the grid varies, the actual rotation speed will change with it. The speed measurement part of the steam turbine control system will measure the actual speed and compare it with the rated speed 3000r/min, and then, through frequency difference amplification and regulator servo control, control the opening extent of CVs and ICVs to form a negative feedback of rotation speed, which will keep the rotation speed within a preset range. All the above-mentioned 10 admission valves are driven by oil servo motors that adopt HP fire-resistant oil as working medium. Except the six control valves (CVs and ICVs) that are controlled continuously by using servo valves and microcomputer interface of DEH, the rest two RSVs and two MSVs are controlled by solenoid valves and DEH interface in a two-digit way. In order to guarantee a safe operation, several redundant protection sleeves are available in the hydraulic system: Emergency tripping devices and testing solenoid valves;
HP and LP stop solenoid valves; Overspeed restriction solenoid valve. For the oil sources of HP fire-resistant oil, 2 redundant pressure oil pumps are also available to guarantee a continuous oil supply. For detail, see the specifications for hydraulic system. The primary mission of a steam turbine control system is to adjust the rotation speed of the steam turbine via changing the opening extent of the control valve. When a steam turbine generator unit operates within a grid, its rotation speed responds to the grid frequency. In a grid system, when the whole generated output power is balanced by the power consumed by all loads, the grid frequency will keep stable, i.e., the rotation speed of a grid-connected generating set are adjusted by all the sets in the grid system. For the rotation speed variation resulting from the fast but small load changes in the grid system, the control system of steam turbine can balance it through using the energy accumulation of the boiler, in which the set point of load needs not to be changed, when the control system measures the variation of rotation speed, it automatically changes the opening of the control valve, that is, it changes the power of the generator and makes it adapt to the random fluctuation of the grid load. This is the so-called primary frequency regulation. In order to ensure a rough balance of the primary frequency regulation amounts assumed by the various generator sets in a grid system as well as to get a stable control system, it is required that the static characteristic curves of the various generator sets are roughly the same. The description of the relationship between the power and rotation speed of a steam turbine generator unit under a steady working condition is called the static characteristics of control system. Its slope in general is denoted as δ, the diversity factor of rotation speed. δ =(n1 -n2 )/n0 (1--4) Where, n1 --No-load rotation speed (fixed set point) n2 --Full load rotation speed (fixed set point) n0 --Rated rotation speed In generalδ varies between 3~ 6%, and factory-set value is 4.5%. In general greatly varied non-linearity exists in the valves in the control system. Although correction is conducted, non-linearity may still exist. So a concept of local diversity factor δ* is introduced to represent the degree of the primary frequency regulation in the neighborhood of the operating point. δ* =-(dn/dN).N0 /n0 .100% (1--5) Where, N0--Generator power; n0--Rated speed of rotation; dn/dN--In the static state curve, the derivative of rotation speed to power. Under the same deviation of rotation speed, the greater the δ (δ*) of generator set is, the smaller the power change is; and vice versa. Commonly the static characteristics can be obtained via calculational methods. Assuming that steam parameters and other auxiliary systems are rated, through calculating the static
characteristics of velocity measurement, frequency difference amplification, servo drive, and valves, the static characteristic of the control system can be worked out, and as a result the diversity factors δ and δ* can be obtained. For the generator sets with base loads in a grid system, in order to ensure that they can run at the most efficient operating condition points, a dead zone for primary frequency regulation can be added to the control system artificially. When the rotation speed of a generator set falls into the dead zone, the set will be free of primary frequency regulation, that is, at this point the local diversity factor δ* is infinitely great. For the rotation speed variation resulting from large a load change (in general the change occurs slowly) in a grid system, a method to change the load set point of the control system can be used to change the power of generator and make it adapt to the random variation of the grid load, as a result the rotation speed is controlled. This is the so-called secondary frequency regulation. Changing the set point of the control system can make a translation of the static characteristic line; as a result under the same rotation speed, the different line corresponds to different power. All modern steam turbine generator units belong to a reheat unit system, that is, one boiler matches one steam turbine. Thus in order to sucessfully complete a secondary frequency regulation task, not only the load set point of a steam turbine control system but also that of the boiler control system shall be changed properly, so that adequate energy can be provided and the boiler can run safely. This is the so-called coordination control. In a grid system in general it is the specified generator sets that participate in secondary frequency regulation. These generator sets receive the signals from the automatic frequency controller to carry out the secondary frequency regulation. For large changes in load, some special peakload units will be set up for peak regulation. On receiving the load change instructions given by the control center, the peakload units will change the loads they assume. In general the control center formulates its dispatching schedule based on the statistic law of load change and sends load increasing or decreasing instructions to the peakload units. For the generator sets that participate in secondary frequency regulation and automatic peak regulation, coordination control must be exercised. Commonly there are three ways for the coordination control of unit and boiler: Boiler following way: When the steam turbine control system receives the instruction of secondary frequency regulation to increase the load set point, first of all it turns up the steam turbine's control valves to increase the generator power. Then the increase of steam flow will decrease the throttle pressure. At this point the boiler control system can detect such a variation, and then it sends signals to the fuel control valve to increase the charge of fuel, which will finally keep the throttle pressure invariable. Steam turbine following (pressure regulated by steam turbine) way: When the boiler control system receives the instructions of secondary frequency regulation to increase the load set point, first of all it will turn up the fuel control valve. With the increase of fuel, the throttle pressure and steam flow will increase, and as a result the generator power will increase. For the purpose of keeping the throttle pressure as a constant, the steam turbine control system adopts a steam pressure feedback system, which can change the control valve opening and increase the steam flow and finally keep the pressure as a constant.
Steam turbine following (sliding pressure) way: When the boiler control system receives the instruction of secondary frequency regulation to increase the load set point, it will turn up the fuel control valve. With the enhancement of combustion intensity, the throttle pressure and steam flow will increase and thus the generator power will also be increased. But the steam turbine control system maintains the control valve in a fully open position all the while. Unit-boiler coordination control mode: The method has the advantages of both the above ways. The power instruction of secondary frequency regulation directly acts on both steam turbine control system and boiler control system. First, it changes the opening of control valve. Within the range of allowable variation of pressure, by using the boiler's accumulation of energy, it improves the load response speed; meanwhile it changes the fuel control valve. With the change of boiler output, the throttle pressure maintain constant. The combined start by HP and IP cylinders is a traditional mode. With this method, the steam simultaneously enters into HP cylinder (intermediate pressure cylinder) by way of CV (ICV) from superheater (intermediate superheater) and finally brings the steam turbine to a rated operating state. During the start, in order to reduce the throttling loss from ICV, the influence resulting from intermediate superheater needs to be reduced. Under their respective working pressures, the ratio of the flow capacity of CV to that of ICV is 1:3. During the start, in general a full-admission method (throttle regulation) will be adopted for the HP cylinder, so that the heat exposure will be uniform and thus the heat stress will be reduced to the minimum. Under normal operation, because the temperature field in the cylinder is roughly stable, a partial admission method (nozzle regulation) will be adopted for the HP cylinder, so that the throttling loss can be reduced and the efficiency can be improved. During the start, because the physical dimensions of rotor and cylinder are very large and the temperature of the heating surface builds up quickly, staying at certain points during speed raising and load up is required to reduce the heat stress of steam turbine. This is called warm-up of turbine. A rotor has its inherent natural frequency of vibration. During the rotating of a rotor, when the exciting frequency resulting from the eccentric mass occurring prior to reaching equilibrium is in agreement with the natural frequency of vibration, resonance will occur; at this point the rotation speed is called critical speed of rotation. The resonance amplitude will increase with time, and too large a amplitude will destroy the steam turbine generator unit; therefore, it is required that the steam turbine shall rush through the zone in which critical speed of rotation occurs. In general a steam turbine generator unit is required to operate in a grid. Synchronous grid-connection means a process in which a steam turbine generator unit is connected to an electric grid after it reaches its running rotation speed. The conditions for synchronous grid-connection are that the switch is closed and the potential difference of phase between both sides (generator, electric grid) of oil switch is equal to zero, that is, both sides have the same phase sequence, voltage, frequency, and phase. The EHC adopts Foxboro's advanced open industrial control system, I/A Series, which includes 2 cabinets, 1 printer, 1 application operating station AW51 (with the functions of operator station (hereafter referred to as OIS) and engineering work station (hereafter referred to as EWS)), and 1 OIS WP51.
OIS is a major device used to conduct a human-computer dialogue between power plant operators and steam turbine control systems. The printer is used to record all kinds of inportant data and keep them in the archives when necessary. EWSs facilitate the design, debugging, and revising of control logic. The DEH adopts two-circuit AC 240VAC UPS for power supply and has redundancy design in the interior. The internal power supply of I/A Series is realized by Industry Power Module (hereafter referred to as IPM). One advantage is that the failure of one power supply module will not affect the whole power supply; and the design is also featured by good heat dispersion, simpleness, flexibility, safety, and high quality. Every card has a power supply with both master and auxiliary IPMs. Based on a design concept of decentralized control, the control system exercises its automatic control by using a hydraulic servo system with I/A Series function module configurations. The package unit consists of serialized standard hardware modules, each of which can complete its respective functions independently and can communicate with each other.
Rate of Rotation speed “two-out-of-three” change of logic load/pressure
CCS setting Operator setting Automatic setting
Target value
Rate of change of rotation speed
Rate limiter Out of grid connection
Primary frequency setting
Set point
Set point selection
Automatic setting Rate limiter
Adder
TPC action
Adder Power
Throttle pressure Power loop governor
Speed loop governor
Throttle pressure loop governor
Power loop out
Throttle pressure loop in
Out of grid connection Manual setting
Manual Lower selection
Overspeed
Manual minus
Valve limit Runback setting
Runback action Trip
Manual plus
OR gate
Gain 3 Function generator
Input 1
Single valve Sequential valve function function generator generator
Control signal
Valve test logic Valve test logic
Output
Input 2
Single/Sequential valve switch logic Valve test
Valve test To ICV servo card To CV servo valve
Schematic diagram of a control system
Output switch function (When the control signal = 1, output = input 1; when the control signal = 0, input = output 2)
2 Control system configuration 1 The DEH control system processor CP60 is divided into two pairs, of which the first pair is defined as basic control station (BTC) to complete such functions as overspeed protection and basic control of steam turbine, and the second pair is defined as automatic control station (ATC) to complete such functions as steam turbine parameter monitoring and on-line testing. The hardware configuration is mainly composed of the following parts: FOXBORO standard cabinet; DINFBM Template; AW51 Application operating station; WP51 Operating station. 2
Board Configuration for DEH system is as follows: BTC (basic control station); Three FBM206 velocity measurement boards; Six FBM204 AI / AO boards; Four FBM241 DI/ DO boards. ATC station (automatic control station); Three FBM201 large-signal AI boards; Three FBM202 TC signal AI boards; Four FBM203 RTD signal AI boards; One FBM204 AI / AO board One FBM207A DI board Three FBM241C DI / DO boards. The board configuration for DEH system is shown in Figure 2-1.
2－1
Control cabinet
The installation has two cabinets in total, in which the majority of the important boards and related connecting pieces, wires, and cables of DEH are installed.
Fro nt boar d
Printer
Cont rol proc essor (BT C)
Fro nt boar d
CV1 Servo board DFSC
CV2 Servo board DFSC
on site
LCD color
CV4 Servo board DFSC
CV2 Servo board DFSC
Cont rol proc essor (AT C)
Engineer keyboard
MSV2 Servo board DFSC
On-site servo valve /LVDT
on site
Redundant on site bus（IEE1118）
WP51 operating station processor
Redundant node bus（IEEE802.3）
Engineer keyboard
LCD color
Figure 2-1 DEH system configuration diagram
On-site servo valve /LVDT
CV3 Servo board DFSC
CV1 Servo board DFSC
AW51 application operation processor
Redundant on site bus (IEEI118)
Speed measure ment signal
Fro nt boar d
Overspeed 103% action / Overspeed 110% action
Overspeed 103% action / Overspeed 110% action
Overspeed 103% action / Overspeed 110% action
2－2 Boards of I/A Series
The control system of I/A Series consists of the following kinds of boards: 1 Control processor CP60; 2 Single-channel isolation voltage monitoring/contacting signal input interface module FBM207; 3 Isolated DI / DO board FBM241; 4 Isolated AI board FBM201; 5 Isolated thermocouple /mV AI board FBM202; 6 Isolated hot resistance AI board FBM203; 7 Isolated AI / AO board FBM204; 8 Channel isolation, impulse input interface module FBM206; The above boards are specified in the hardware manual provided by Foxboro. 2－3
AW51 application operating station
There is a suite of AW51 application operating station, which includes one Ultra SPARC Ⅱ RISC 64 -bit processing machine, one colour 21LCD, one printer, and some mouses amd keyboards. AW51 is designed to help engineers to conduct design, configuration, debugging, and monitoring. Its major functions are as follows: 1 Application function AW51 has the application functions related to display, production control, customer application program, diagnosis, and configuration. AW51 also has the application functions to developm and carry out data processing and filing service that need expansion (FOXBORO and the third party). AW51 reduces the mass storage file application required by the tasks of itself or from other stations. Together with one or more file memory equipment, AW51 is used to conduct loading for other stations; to perform production control tasks, such as data authentication, electronic spreadsheet and performance calculation; to provide normal functions, such as operator HELP and electronic files; to offer an application development environment, such as compiler software, connection software, and text editing software. 2 Operating station functions In a video frequency monitor, it can generate video signals to display both graphical and literal information. Besides video frequency monitors, the devices connecting to AW51 can include touch screen, mouse, or ball cursor. These optional devices provide command or data input as well as display selection and alarming management. 2－4
WP51 operating station
There is a suite of WP51 application operating station, which includes one Ultra SPARCⅡRISC
64-bit processing machine, one colour 21CRT, and some mouses and operator combination keyboards. WP51 is the major device used to conduct a human-computer dialogue between power plant operators and steam turbine control systems. Together with its peripheral equipment, WP51 provides an interface between users and all the system functions. Its major functions are to provide command and data input, display selection, and alarming management. It receives both graphical and literal information from the application processor or any other system station, and displays the information on the video display. 3 Servo valve controller DEA servo valve controllers are specially designed for DEH. The controller adopts 16-bit SCM 80C196 chips and high-performance programmable logic array CPLD to form its control core; meanwhile it adopts 16-bit A/D and D/A chips to improve its conversion accuracy. The supply unit adopts advanced DC-DC isolating converters to ensure that the operational power supply and the electric power supply can be adequately isolated, and that the work of the power loop of controller is effective and reliable. In terms of hot pluggable technology, the controller adopts Philips I2C serial bus technology, with which the values of full-close and full-open of LVDT are stored into E2PROM during the checking procedure, and as a result hot plug is realized. The operational principle of servo card is, through the acquisition of LVDT's measured values and the setting values sent out by the control system to form a comparing element and then through PI calculation, to output regulating currents to control the movement of control valves, so that the opening of valve can reach the setting expected position. 3－1 Servo valve controller hardware overview The hardware of a servo valve controller primarily includes servo cards and cabinet modules: 1 Servo cards Servo cards adopt a four-layer printed plate wiring technology, which is highly resistant to EMC. Major parts of the plate are imported from overseas. CPU adopts advanced 16-bit SCM 80C196 of Intel with a very high calculating and processing speed. Built-in WATCH_DOG is available for the SCM, which shows a robust self recovery capability. 16-bit A/D and D/A chips are adopted for the acquisition and output conversion of analog signals, which has high conversion accuracy. One of the A/D chips picks up various simulating signals through its front-mounting channel selector. In the two D/A chips, one is used for valve position signal output, and the other for current output after PI calculation. Isolated amplifiers and external interfaces are adopted for the separation of all analog signal channels of servo card. By adopting the I2C serial bus technology of Philips, during the checking the full-close and full-open values of LVDC resulting from checking are stored to E2PROM, which as a result will not affect the service of the card for power loss reasons. The LVDT acquisition channel employs two circuits, so when one of which fails it can switch to the other. There is also a built-in oscillating circuit, which can be used for the excitation signals
of LVDT. The frequency and amplitude of excitation signal can be adjusted by setting up the jumpers on the card. 2 Cabinet modules 19" electromagnetic shielding cabinet and modules are adopted. All the connecting terminals at the rear of cabinet are welded to the power source motherboard for the convenience of wire connection. A push-and-pull mechanism is used for cards so that the pull and insert is very convenient. 3－2 Servo valve controller function overview 1 Control drive Servo cards pick up the feedback values of LVDT, then compare the values with the specified instructions from the control system (4-20mA signals), and then, through PI calculations, output regulating currents (-40mA-40mA) to actuate the servo valve, and as a result control the travel of the valve to a specified opening degree. While conducting auto regulation, servo cards can also send a valve opening signal (4-20mA current signal or 1-5V voltage signal) to the control system as the travel instruction. The scale factor and integrating factor used for PI calculation can be adjusted through a thumb wheel dial. According to the indicator lights on panel the working state of a card can be know in real time. 2 Two-circuit LVDT switch Servo valve controllers provide two-circuit LVDT switch functions, that is, once the working LVDT fails, the servo card can detect the corresponding trouble and switch to the standby LVDT automatically. 3 Check Servo valve controllers also provide check functions, that is, they can output close signals and open sigals to control the movement of valves, make the valves fully open or fully closed, and as a result proceed to the setting of servo static relation. Bias 4 Servo valve controllers also provide bias functions, that is, they can output current or voltage signals to force the valve closed under a bias input condition.
5
Manual function Manual functions are also available for a servo valve controller, that is, manual increase and decrease operations can be conducted for valves.
3－3 Operating instructions for servo valve controller Prior to using a servo valve controller, first set up the jumpers. Meanwhile, before turning on the power, be sure to connect the wires for the cabinet accurately.
1
Jumper setup
The jumper setup for master servo cards and digital-analog cards is as follows: 1.1
Jumper setup for master servo cards
J1 and J23 are used for the selections of CPU's working conditions. Of them, J1 is the jumper for CPU's working clock, and J23 is used to select the operation mode of program memory. The jumper connection mode set up at factory for J1 is of short-circuit (CPU is working), while that for J23 is of (2, 3) short-circuit. Change is not allowed for both of them. J3 and J8 are used to select the category of LVDT1 feedback (AC and DC selection). Of them, the mode of J3 (1, 2) short-circuit and J8 disconnection is to select the LVDT1 AC feedback system; while the mode of J3 (2, 3) short-circuit and J8 short-circuit is to select the LVDT1 DC feedback system. J4 and J9 are used to select the category of LVDT2 feedback (AC and DC selection). Of them, the mode of J4 (1, 2) short-circuit and J9 disconnection is to select the LVDT2 AC feedback system, while the mode of J4 (2, 3) short-circuit and J9 short-circuit is to select the LVDT2 DC feedback system. J10 is used to select the output mode for servo drive 1. The mode of J10 (1,2) short-circuit means the servo drive 1 selects a current operation mode; the mode of simultaneous short-circuit of both J10 (1, 2) and J10 (1,2,3) means that servo drive 1 selects a voltage operation mode. Under the voltage operation mode, the mode of connection shall be changed; for details, see the following wire connection illustrations. J11 is used to select the output mode of servo drive 2. The mode of J11 (1,2) short-circuit means the servo drive 2 selects a current operation mode; the mode of simultaneous short-circuit of both J11 (1, 2) and J11 (1,2,3) means that servo drive 2 selects a voltage operation mode. Under the voltage operation mode, the mode of connection shall be changed; for details, see the following wire connection illustrations. J12 (1,2) short-circuit does not include fluter component, while J12 (2, 3) short-circuit is the superposition of servo drive signals and fluter component. The fluter frequency can be changed through the setup of jumper combination (J13, J14). Under the condition of a factory setup of (J13, J14) short-circuit, the frequency is in the order of 311HZ; in case of (J13, J14) disconnection, the fluter frequency will become 208HZ or so. The combination of (J15, J16, J17) is used to select the pumping frequency of LVDT. In this card the (J15, J16, J17) is of short-circuit, and the frequency is in the order of 1.7KHZ. If the J17 is short-circuited at factory, the frequency is about 1.1KHZ. The combination of (J19, J20, J21, J22) is used to select the pumping amplitude of LVDT. The maximum amplitude is available for a full short-circuit and the minimum is available for a full disconnection. The descending sequence for sole short-circuit amplitude is J19>J20>J21>J22. In case of the (J19, J20, J21) short-circuit set up at factory, the pumping amplitude is about 3.2V. J18 (1, 2) short-circuit is to use cards for pumping frequency output; J18 (2,3) short-circuit is to use a external pumping source. In service no full open is allowed, because in this way the software will judge it as a pumping trouble of LVDT. 1.2
Jumper setup for digital-analog cards
Disconnection is set up for J1 at factory, and no change is allowed for it. J3 is the setting adjustment. Disconnection is set up at factory, and no change is allowed for it. J2 (1,2) short-circuit is to input setting current signal; J2 (2, 3) short-circuit is to input setting
voltage signal. J2 (3, 4) short-circuit is to input setting current differential signals; no short-circuit of J2 is to input setting voltage differential signals. J4 (1, 2) short-circuit valve position is outputting 1-5V voltage signals, and J4 (2, 3) short-circuit valve positions is outputting 4-20mA current signals. 1.3 Servo cabinet A servo cabinet consists of a electromagnetic shielding cabinet, backboard terminals, and bails. The backboard is a printed circuit board on which all the sockets for servo cards are welded. All external wires access the cabinet through the connecting terminals on the backboard. 1.3.1 Outside view of a servo card cabinet
To top cover and top guide rail
3-3-2
Figure 3-3-1: External view of servo card cabinet In the above Figure, the above part is a front view of a cabinet with servo cards, in which (2) is the socket with a card while (3) is a void socket with no card; the lower part is the top view of the cabinet.
1.3.2
Outside view of backboard of servo card
All external wires access the cabinet through the backboard of the servo card cabinet. TB23 is a
reserved design for communication, useless at present; TB25 is the incoming terminal for 24V DC power supply; TB1-TB20 are the connecting terminals for all the interfaces on servo cards. Each card occupies two connecting terminals, for example, the interface signals of the servo card in the first left bail are accessed and outputted through (TB1, TB2). All the others are arranged in the same way in sequence. The distribution of the connecting terminals of the whole backboard is shown as the following Figure.
TB25
TB23
TB20 TB19 TB18 TB17 TB16 TB15 TB14 TB13 TB12 TB11 TB10 TB9
TB8
TB7
TB6
TB5
TB4
TB3
TB2
TB22 TB21
Figure 3-3-2 Terminals on the backboard of servo cabinet (back view) 1.3.3 Definition of TB25 power terminal on backboard of servo cabinet
1
2
3
4
5
6
7
8
+24V input +
+24V input + +24V input -
+24V input -
Figure 3-3-3 Definition of power terminal
TB1
In the above Figure hte dotted portion denotes the internal wiring of backboard. From the Figure it is observed that the four pairs of terminals (1, 2), (3, 4), (5,6), and (7, 8) have been short-circuited internally, which can not be changed. (1, 2, 3, 4) terminals form a suite of input power source, and (5, 6, 7, 8) terminals form another suite of input power source. The two groups of power can be short-circuited through the jumpers within the backboard. 1.3.4 Definition of interface terminals on backboard of servo card Two terminals serve one servo card. Here (TB1, TB2) is taken as an example to illustrate the meanings of each connecting terminals, which are numbered as 1~16 from the top down.
Emergency manual input (DI) Valve + input (DI) Valve - input (DI) Shutdown bias input (DI) Rapid manual input (DI) Check begin input (DI) Check permit input (DI) IN_COM (input common terminal) Check status ouput (DO 24V/2A) Emergency manual output (DO 24V/2A)
Valve + output (DO 24V/2A) Valve - output (DO 24V/2A) Failure output (DO 24V/2A) OUT_COM t
(input
common
i l)
Servo valve setting+ (4-20mA) Servo valve setting -
TB2
TB1
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
SERV01+(servo 1drive +) SERV01-(servo 1drive -) SERV02+(servo 2 drive +) SERV02-(servo 2 drive -) Valve output +(1-5V or 4-20mA) Valve output -(1-5Vor 4-20mA) LVDT-AC(drive signal output)
LVDT1-1-1(LVDT1 order 1) LVDT1-1-2(LVDT1 order 1) LVDT1-2-1(LVDT1 order 2) LVDT1-2-2(LVDT1 order 2) LVDT2-1-1(LVDT2 order 1） LVDT2-1-2(LVDT2 order 1） LVDT2-2-1(LVDT2 order 2） LVDT2-2-2(LVDT2 order 2） GND(2)
Figure 3-3-4 Definition of connecting terminal 1.3.5 Access of setting signal
There is no differentiation between current and voltage in terms of access of setting signals, and all the signals are accessd through the same terminal. The differentiation of setting current and setting voltage depends on the jumper connection of J2. J2 (1,2) short-circuit is to input setting current signals; J2 (2, 3) short-circuit is to input setting voltage signals. J2 (3, 4) short-circuit is to input setting current differential signals; no short-circuit of J2 is to input setting voltage differential signals.
TB2
+
15
16
Setting current of 4~20MA or setting voltage 1~5V
Figure 3-3-5 Connection diagram with a setting current or voltage 1.3.6
Wiring for LVDT of servo card
Both DC LVDT and AC LVDT are taken into consideration from the point of view of design. Modes of connectionare are shown in the following Figure.
TB1 7 8 9 10 11 12 13 14 15 16
LVDT-AC LVDT1-1-1
LVDT1(AC) LVDT1-1-2
Primary coil of LVDT1初级线圈 LVDT1
LVDT1-2-1
LVDT1-2-2 LVDT2-1-1
TB1 LVDT2(AC)
LVDT2-1-2 LVDT2-2-1
LVDT2-2-2 GND(2)
Primary coil LVDT2初级线圈 of LVDT2
8
LVDT1-1-1
+
9
LVDT1-1-2
-
12
LVDT2-1-1
+
13
LVDT2-1-2 -
LVDT1(DC)
LVDT2(DC)
*LVDT’s input positive and negative 10V * LVDT的输入正、负10V
Figure 3-3-6: LVDT connection diagram 1.4
Operation instructions
The operational process of servo card will be detailed in the following. 1.4.1
Power-up initialization
Dial the thumb switch from high-order positions to low-order positions. When the four-digit switch SW1 is switched as ON_OFF_ON_OFF and the eight-digit switch as OFF_ON_OFF_ON_OFF_ON_OFF_OFF, the servo card will begin its initialization process; at this time, RUN light is green, D0-D7 serial lights turn on, the four (RXD, TXD) lights are also on, and the program will conduct initialization presetting for the data stored in the E2PROM. 1.4.2
Regulating pqrameter setup
SW2 is used to adjust PI parameters, and at this time SW1 shall be switched to OFF or ON position completely. See the following Table for detail about SW2. Parameter name Thumb switch position ON position OFFposition ON=0 OFF=1
KP 1
No use
KI 2
0 0 1 1 KP=SW2(1-4)
3
4
5
6
0 1
0 1
0 0 1 1 KI=SW2(5-7)
7
8
0 1
From the above Table it can be learned that the first four digits (1~4) of SW2 are used for the setup of scale factor; digits 5~7 are used for the setup of integrating factor; the eighth digit has no use in the control parameter setup. When SW2 is switched downwards to the 0FF position, the value is 1; when SW2 is switched upwards to the ON position, the value is 0. KP's dial-up consists of 4 digits, which form 16 scale factors; the greater the dial-up value, the greater the scale factor. KI's dial-up consists of 3 digits, which form 8 integrating factors; the greater the dial-up value, the smaller the integrating factor, and the faster the integral calculation is. 1.4.3
Check function
After the DI signal "CHECK PERMITED INPUT” is effective, CHK light on panel turn on. After the signal "VIRIFICATION BEGIN" input is effective, CHK light flashes slowly, and the servo card outputs forward current (or negative voltage) to drive the servo valve and make it move towards the valve closing direction; after the valve reaches the full close position, it is time to wait for current bias, and at this time (D4,D5) light turns on; with a minute of time delay, CHK light flashes quickly, and the servo card outputs negative current (or positive voltage) to drive the servo valve and make it move towards the valve openning direction; after the valve reaches the full open position, it is time to wait for current bias, and at this time (D4,D5) light turns on; with a minute of time delay, the servo card will record the full close and full open values from check, and store them in the serial storage chip E2PROM. CHK light is normally on, and the check is over. 1.4.4
Bias function
In any case, after the DI signal' “SHUTDOWN BIAS INPUT” is effective, the servo card will output forward current (or negative voltage) to close the valve forcefully. The current output is in
the order of 50mA. 1.4.4
Manual function
After the DI signal "EMERGENCY MANNUAL INPUT” is effective, the MAN light on panel will turn on. At this time if the signal "VALVE +" input is effective, the UP light on panel will turn on, and the current output of servo card will increase negatively (or increased output voltage) to open the valve; if the signal "VALVE -" input is effective, the DOWN light on panel will turn on, and the current output of servo card will increase positively (decreased output voltage) to close the door. 1.4.5
DIT potentiometer hole:
Screwdrivers can be used to adjust the fluter amplitude potentiometer through the hole. 1.4.6
DIV test hole:
The amplitude of fluter can be tested through the hole. 1.5 Field use instructions It is necessary to give a brief illustration for the use of servo card on site due to its intrinsic complexity.
1.5.1
Check prior to use
Prior to the use of card, jumpers must be well set up in advance according to corresponding valve category, setting category, and valve position feedback category, and a thorough inspection is required for the setup to ensure an absolute accuracy. 1.5.2
Installation of LVDT
During the in-situ installation of LVDT, in a general way first look for the zero point; then according to the travel of oil servo motor, with the zero point as the symmetric midpoint, look for the full open positions or full close positions for installation. The way to look for the zero point is to look for the position of LVDT when two circuits of secondary voltage is equal, or to look for the midpoint of LVDT within the effective travel by drawing out the LVDT rod. The card has no high requirements for the accuracy of zero point. 1.5.3
Adjustment of LVDT secondary wire connection sequence
First be sure that the valve is in a full close state, and LVDT has been assembled and well wired. Take TB1 as an example.Measure LVDT1 order 1(the voltage between terminals (TB1 (8,9)) and LVDT1 order 2 (the voltage bewteen terminals TB1(10,11); if the measured AC feedback voltage LVDT1 order 1 is lower than order 2, then the wire connection is right; otherwise, order 1 and order 2 shall be exchanged.The redundant LVDT2 is the same as LVDT1. The measure points are LVDT2 order 1 (voltage between terminals TB1 (12,13)) and LVDT2 order 2 (voltage between terminals TB1 (14,15)). If the redundancy LVDT is not used, LVDT shall be conncected
to the corresponding TB1 terminal, that is, the feedback of LVDT is connected to the two feedback input circuits of TB1 simultaneously. 1.5.4
Determination of servo outgoing feeder
After determining the secondary linear ordering of LVDT, increase or decrease the setting quantity until the valve moves; then judge whether the movement direction of the valve is in accordance with the setting direction; if it is, then the servo output connection is right; otherwise, exchange the two output lines. Under the current operation mode, if only use one circuit of servo output, short-circuit the other circuit or add a small load onto it. 1.5.6 Use of initialization In general, unless in trouble, the cheking procedure can completely cover the stored LVDT check values. If no success can be get again and again, an initialization process is available to check whether the serial memory is damaged. If a reset operation is applied but success is still unavailable, check the external interface signals. If resetting is unavailable, the card has problems. 3-4 Fault indication for servo valve controller The card uses the indicator light on the front panel for failure predication. The meaning of the indicator light as well as their combination indicating troubles are described below:
1
Definition of lights on panel and functional specifications for test hole
RUN light : When the card is in its initialization status, the light is orange (cold boot time is in the order of 2 seconds, and self-recovery reset time is dozens of milliseconds); when in normal operation, it is green. RXD light: RXD is used to indicate which LVDT is working. If ARXD is on, it indicates that LVDT1 is the current working LVDT; if BRXD is on, it indicates that LVDT2 is the current working LVDT. TXD light: TXD light serves as the indication of access LVDT. If ATXD is on, it is LVDT1 access; if BTXD is on, it is LVDT2 access. If both ATXD and BTXD are on, both LVDT1 and LVDT2 are on. Note: The criterion for the function is that when the valve is in the safe full close position without servo drive, the feedback of LVDT is not zero. So in order to make the function valid, when LVDT is installed it is necessary to avoid the full close state, and the LVDT rod cannot be at mid point. D0-D7: The combination of D0 to D7 lights can be used to display various failure states. Under a normal
condition, the running light is on; however, if there is a failure state, the running light will turn off and the corresponding failure combination code is displayed. MAU: Manual indication, meanwhile the DO signal "EMERGENCY MANUAL OUTPUT" of servo card is effective. ERR： Servo card fault indicating light. When the A/D chip and integral output D/A chip of a servo card is abnormal, the light will be on; when the pumping frequency is abnormal, the light will flash quickly. When a A/D chip is abnormal, the valve will be closed forcefully. When the light is on, it also sets up the DO signal "SERVO TROUBLE OUTPUT" as effective. CHK： Check light. After the DI signal "CHECK PERMITED INPUT" is effective, the light is on; when the valve moving towards the full close direction is checked, the light flashes slowly; when the valve moving towards the full open direction is checked, the light flashes quickly; when the check is over, the light is on. After the DI signal "CHECK PERMITED INPUT" is canceled, the light is off. When the light is on, it sets up the DO signal "CHECK OUTPUT" as effective. UP: Manual up indicator. When the light is on, it sets up the DO signal "VALVE POSITION UP OUTPUT" as effective. DW: Manual down indicator. When the light is on, it sets up the DO signal "VALVE POSITION DOOW OUTPUT" as effective. 1.10 Illustrations for D0~D7 composite codes The composite codes of D0~D7 are used to denote various failures during operation, which are detailed in the following Table. Panel light status D0 ON D1 ON D2 ON D7 OFF
D3 ON D4 ON D5 ON
D7 ON
D6 ON D0 ON D1 ON D2 ON D3 ON D4 ON D5 ON D6 ON
Failure meaning A/D conversion chip failure Valve position output D/A conversion chip failure Adjustment output D/A conversion chip failure Undefined Disconnection or bias of servo drive 1 Disconnection or bias of servo drive 2 E2PROM read/write failure Illegal check value for LVDT1 Illegal check value for LVDT2 LVDT1 overrun LVDT2 overrun LVDT driving signal failure Setting input signal failure Undefined
ERR output Yes
Yes
Flicker
1.11 Special illustrations for failure indication 1.11.1 In case of a failure of A/D conversion chip, RUN light is green, ERR light is red, and (D0, D1, D2, D4, D5) lights are red. The servo drive will output a 39mA current to close the valve. When an A/D conversion chip fails, all analog variable acquisition will fail, so except its own failure is displayed, other failures will also be displayed. 1.11.2 In case of a failure of adjustment output D/A conversion chip, RUN light is orange, ERR light is red, and (D2, D4, D5) lights are red. In this case the output and acquisition of current will not be accurate and effective any more, so the failure of servo drive will also be displayed.
1.11.3 Other failure cases can be accurately judged according to the above Table. 4 Major functions of DEH control system Major functions of the control system are as follows: Automatic setting of static relation of servo system; Remote latching-on prior to start; Automatic thermal condition judgement; HIP CV start mode Full-range automatic closed-loop control of rotation speed from hand-turning speed to rated speed; Overspeed control and overspeed protection functions available; Able to realize rapid synchronous grid-connection with the interface of automatic synchronization installation; Flexible selection between power control and valve position control and free switching; Valve management functions available; On-line HIP SV and HIP CV activity tests available; Able to realize remote spray oil testing and automatic latching-on after testing; On-line HP tripping solenoid valve testing available; Mechanical and electric overspeed testing available; Throttle Pressure Control (TPC), load control, and valve position control functions availale; DEH-controlled SV and CV leak testing available Cooperating with CCS to realize RUNBACK functions; Cooperating with CCS to finish unit-boiler coordination control; Sound parameter monitoring functions available; ATC control available. 4-1 Automatic setting of static relation of servo system Prior to the start of a unit, the static relation setting for servo valves, LVDTs, and servoboards must be completed to guarantee the control accuracy and linearity of all servoactuators so that the unit's requirement for the static relation of the servo system can be met. Such valves as CV, ICV, and MSV can be checked simultaneously or respectively. The process goes on at the OIS display. 1 The setting of static relation for a servo system prior to the start of a unit must fulfill the following conditions: Latching-on is available for the steam turbine. All valves have been closed. No steam is allowed in front of a SV; otherwise, when the valve is under check and the rotation speed of the unit is greater than 100r/min, DEH will conduct tripping automatically. In other words, the rotation speed of the steam turbine must be less than 100r/min. 2 Calibration procedure a) Enter into OIS "STEAM TURBINE VALVE CALIBRATION" picture, and select "SINGLE
CALIBRATION PERMIT" or "DOUBLE CALIBRATION PERMIT" (Both can be selected simultaneously for off-line calibration, but only one of them can be selected for on-line calibration). b) When "SINGLE CALIBRATION PERMIT" is lit, only the valves of odd number can be selected for calibration; when "DOUBLE CALIBRATION PERMIT" is lit, only the valves of even number can be selected for calibration. Select the valve to be checked, the corresponding key is lit. c) After selecting the valve for check, begin to check the corresponding servoboard, and at this time the "CHK" light on the servoboard begin to flicker (down flicker frequency is slow but up flicker frequency is fast), meanwhile the "VALVE CALIBRATION IN PROGRESS" light also begin to flicker (the same flicker frequency with that of "CHK" light). d) When "CHK" light and "VALVE CALIBRATION IN PROGRESS" light are normally on, the check is over. e) Again click the "single CALIBRATION" or "double CALIBRATION" buttons to quit from the check mode, and at this time the "CHK" light is off and the "VALVE CALIBRATION IN PROGRESS" light turns grey. f) After finishing the check, inspect the static relation. Through the OIS station send out a valve opening instruction, then check whether the opening instructions and the actual valve opening meet the static relation's requirements; if not, conduct setting again according to the above steps. 4-2 Automatic thermal condition judgement A steam turbine's start process is also a heating process for both the steam turbine and its rotor. In order to reduce the heat stress resulting from start, for different initial temperature, different start curve shall be adopted. Every time when latching-on is conducted for DEH, the thermal state of the turbine is automatically determined based on the temperature of the inner upper wall of the HP inner casing at the control stage of the unit. If the temperature signal from the upper wall fails, it wall be replaced by that of the lower wall automatically. T≤150°C 150°C
Cold state; Mild state; Hot state; Extremely hot state. 4-3 Automatic remote latching-on prior to start
Prior to start, first generate an latching-on instruction through OIS; then reset the testing valve block to make the emergency tripping device engaged. After latching-on, a HP safe oil pressure is established, and all SVs and CVs are in a close state. Permissive conditions for latching-on:
Tripping of steam turbine; All valves in a full close state. Push the "RESET" button in the OIS "AUTOMATIC CONTROL" menu, then the HP tripping solenoid valve acts, the oil pressure in the upper chamber of the slide valve on the emergency governor gear is established, and HP security oil is established; at this time the OIS "AUTOMATIC CONTROL" menu displays the "RESET" status of the steam turbine. 4-4 Startup and operating mode 1 Prewarming of HP cylinder Prior to start, prewarming can be conducted through introducing HP by-pass steam to the HP cylinder by way of RFV prewarming valve and HP cylinder's steam outlet. Drivers send out a prewarming instruction to open the prewarming valve RFV, close the vacuum valve VV, and close the HP exhaust check valve. When the temperature of the HP cylinder reaches the specified value, keep warming for an hour, and close RFV, so the prewarming of HP cylinder is completed. 2 HP SV (HP stop valve) prewarming Operators send out a prewarming instruction to open 10% of the HP SV in one side and introduce main steam into the two SVs; when the temperature of the valve bodies reaches the specified value, the prewarming is over and the HP SV shall be closed. 3 Startup mode 3.1 Intermediate pressure (IP) cylinder start After the prewarming is completed and the start condition is available, open VV. Select the "STARTUP MODE" button in OIS, and then select the "IP CYLINDER STARTUP" mode. The IP control valve will be open gradually and the speed of the unit will be raised to 3000r/min. After grid connection, the unit has an initial load. Set up the target load and load rate. Push the "PROCEEDING/HOLD" button. At this time a "PROCEEDING" status displays on the menu and the unit begin to raise its load. In order to keep the reheating pressure constant, the lower by-pass system begins to close gradually; when the lower by-pass system is fully closed, HP and IP cylinder switching can be conducted. Push the "CYLINDER SWITCHING" button, the switching of HP and IP cylinder begins, that is, the IP control valve opens gradually. In order to keep the throttle pressure constant, the higher by-pass system begins to close. When the steam admission ratio of HP cylinder to IP cylinder reaches 1:3, it is thought that the switch is over. HP and IP control valves participate in control simultaneously. When the cylinder switching is in progress, the load control will be cancelled and the VV will be closed. 3.2 Combined start by HP and IP cylinders When the by-pass system has performance problems or hot state and extremely hot state are used for start, a combined start mode by adopting HP and IP cylinders can be adopted; at this point HP and IP control valves are opened simultaneously.
4-5 Speed control Prior to the grid-connection of steam turbine generator unit, DEH is a rotation-speed closed-loop isochronous control system. Its set point is the setting rotation speed. Through the calculation of PID regulator, the servo system uses the difference of setting speed and actual speed to control the opening of the oil servo motor, making the actual speed vary with the setting speed. As per different start modes, the oil servo motor is ICV or CV and ICV. After a target speed is set, the setting speed automatically approaches the target speed with a setting acceleration rate. When the speed reaches the critical speed zone, the acceleration rate will be automatically changed into 400r/min/min. During speed raising, often the steam turbine needs to be heated in medium or high speed to reduce heat stress. 1
Target rotation speed
Except the target rotation speed set up by operators through OIS, under the following conditions, DEH automatically set up the target speed: When the steam turbine is just engaged, the target is the current rotation speed; When the oil switch is just disconnected, the target is 3000r/min; In a manual state, the target is the current rotation speed; When the turbine has tripped, the target is zero. When the target exceeds the upper limit, it has been changed into 3060 or 3360r/min; In a self-start mode, the target depends on ATC; In synchronization, the target varies with the change of the synchronous fluctuation signals (rate of change 60r/min/min). When the target is set in the critical range by mistake, it has been changed to a specific critical value. 2
Acceleration rate
Set by operator, within (0~400) r/min/min; Under a self-stardup mode, 120, 180, 360r/min/min; Within the critical speed range, 400r/min/min. 3
Critical speed of rotation
The calculated values of combined critical speed are: First-order: 1399r/min electric machine rotor first order
Second-order: 1679r/min HIP rotor first order Third-order: 1753r/min LP rotor first order Fourth-order: 3465r/min electric machine rotor second order In order to avoid the critical speed of rotation, DEH sets up two critical speed zones, the range of which is about ±50r/min different from the calculated values of the critical speed. If the measured critical speed is greatly deviated from the calculated value, the critical speed zone value and the critical speed plateau value must be revised. Warm-up of turbine The warm-up rotation speed depends on the specific unit, and each unit has its own warm-up speed. When the target rotation speed is reached, the speed raising can be ceased for warm-up. If intermitting is required during speed raising, the following operations can be conducted: When not in an ATC mode, the operator sends out a "HOLD" instruction; When in an ATC mode, the operator sends out a "HOLD" instruction after the system quits from the ATC mode. Within the critical speed zone, the hold instruction is invalid, and only the target rotation speed can be modified. Note: during the warm-up, the resonant frequency with rotor and blades must be avoided. 4
3000r/min constant speed
When the steam turbine's speed is stabilized above 3000±2r/min, all systems conduct an inspection for grid connection. A pseudo grid connection test is conducted for the generator to check the reliability of the automatic synchronous system and the accuracy of adjustment. During the test period, the isolating switch on the side of generator power grid is disconnected and a pseudo grid connection test signal is sent out. As the normal condition, the automatic synchronous system changes the frequency and voltage of generator through DEH and generator excited system. When the synchronization condition is met, the oil switch is closed. Because the isolating switch is disconnected, actually the generator is not grid-connected. As a result, during the pseudo synchronization testing, when DEH receives the pseudo grid connection test signals and the oil switch is closed, it does not judge that the generator is grid-connected. In this way, an initial load resulting from grid connection and the resultant speed rising can be avoided. During speed rising, warm-up is required. Push down the "HOLD" button in the "AUTOMATIC CONTROL" menu of OIS. At this point, the OIS menu displays a "HOLD" status, and the rotation speed keeps constant for warm-up. If the unit is stepping across the critical zone, the operation of clicking "HOLD" button will be invalid. Attention: in some works, for no DI signal of pseudo grid connection is sent to DEH, during the
test no grid connection signals can be sent to DEH; otherwise, DEH will think that the unit has been grid-connected and thus turn up the control valve with an initial load, which will result in considerable rise of rotation speed. 4-6
Synchronous grid-connection control
When the rotation speed of steam turbine is about 3000r/min, if DEH receives the synchronous request signals from an automatic synchronization installation, automatic synchronization functions can be input through OIS; at this point DEH can receive the rotation speed increase or decrease instructions of the automatic synchronization installation, control the rotation speed, make it in agreement with the grid frequency. The speed rate is 60r/min/min. At this point, the generator voltage (including amplitude and phase) is controlled by the exciter control system. When the grid connection condition is available, the generator will be grid-connected. In case of one of the following instances, the synchronization mode will be cancelled. Rotation speed: less than 2985 r/min or greater than 3015 r/min; Manual status; Rotation speed failure; Have been grid-connected; Tripping of turbine. 4-7
Control after grid connection (non CCS mode)
When a steam turbine generator unit is just grid-connected, DEH will immediately increase the setting value, which will make the generator carry an initial load and thus avoid the occurrence of reverse power. At the beginning of grid connection, DEH will use the throttle pressure to correct the increased setting value, instead of inputting load feedback. Setting value = original value +3+f (p0). At the beginning of grid connection, the target is also equal to the setting value. 1 Load up After the steam turbine generator unit is grid-connected, in order to realize the primary frequency adjustment, rotation speed feedback is available for the control system. During testing or with a base load, load control can also be input. During inputting load control, the target and setting value find expression in the form of MW. After the power control is cancelled, the target and setting value find expression in the percentage of the total flow under the rated pressure. After the target is set, the setting value will approach the target value with a set change rate, and along with it the generator power or throttle pressure will change gradually. During the load up, often the steam turbine needs to be heated to reduce heat stress.
2 Target Except the target set up by operators through OIS, under the following conditions, DEH automatically set up the target: When the power control is just input, the target is the current load (MW); When the generator is just grid-connected, the target is the setting value for initial load (%); In a manual state, the target is the reference quantity (%) (valve total flow instruction); When the control is just cancelled, the target is the reference quantity (%); When the turbine has tripped, the target is zero; Under the mode of control of CCS, the target is CCS setting (%); When the target is too large, it shall be replaced by the upper limit value. 3 Load rate Set by operator, within (0~100) MW/min; During Single / Sequential Valve switching, 5.0MW/min. 4 Warm-up of turbine During the load up of steam turbine, in view of such factors as heat stress and expansion difference, in general warm-up is required. If the load up is required to pause, the following operations can be conducted: When not in a CCS mode, the operator sends out a "HOLD" instruction; When in a CCS mode, the operator sends out a "HOLD" instruction after quitting it from the CCS mode. 5 Power control The power controller is a PI controller, used to compare the setting value and the actual power and output CV and ICV instructions after calculation. Power control input conditions: With a grid-connected unit, the load varying between 6.0MW~310MW; Normal power signal;
No CCS control input No TPC action; No quick release action; No primary frequency adjustment action; No high load restriction action; No low load restriction; The system in an automatic mode When all the above conditions are met, click the “IN” button in the "AUTOMATIC CONTROL" menu of the OIS to input power control. Power control canceling conditions: Operators clicking the "OUT" button in the "AUTOMATIC CONTROL" menu of OIS; Load less than 6.0MW or greater than 310MW; Abnormal power signal; Tripping of steam turbine; Change to a manual mode; High load restriction action; Low load restriction; Quick release action; When reaching the sliding pressure point; TPC action; Primary frequency adjustment action; Tripping of oil switch; CCS control input. When there is power control input, the set point is denoted as MW. When PI isochronous control is adopted, the steady-state load is equal to the set value. 6 Primary frequency adjustment
When a steam turbine generator unit is grid-connected, in order to ensure that the power supply quality meets the requirement of the grid frequency, in general primary frequency adjustment functions is required to input. When the rotation speed of the unit is within the dead zone, the frequency adjustment setting is zero, and the primary frequency adjustment fails to actuate. When the rotation speed is beyond the dead zone, the primary frequency adjustment acts and the frequency adjustment setting changes with the speed variation as per the diversity factor. The diversity factor of primary frequency adjustment is adjustable within a range of 3%~6%. Its factory set value is 4.5%. The adjustment dead zone is adjustable within a range of 0~30r/min. The factory set value for frequency dead zone is ± 10/min. When controlled by CCS, the frequency adjustment dead zone changes itself into ± 30r/min. The diversity factor and frequency adjustment dead zone of primary frequency adjustment can be displayed in the "AUTOMATIC RESTRICTION" menu of OIS. Primary frequency adjustment function input condition: The system being in a automatic state; After the load greater than 10% of the rated load for the first time. 4-8 CCS control DEH can cooperate with CCS to complete the coordination control of unit and boiler. Under the CCS control mode, DEH is one of actuator of CCS. DEH automatically cancels the power control and, according to the instructions given by CCS, control the opening of all valves. DEH can give a proper judgment or restriction to CCS instructions in terms of higher limit, lower limit, and rate of change. The signal transmission between DEH and CCS is tabled as below: No.
Signal name
Signal direction CCS→DEH CCS→DEH
1 2
CCS control request CCS instruction
3 4
CCS control input DEH→CCS Valve position of steam DEH→CCS turbine
Signal category Digital signal 4∽20mA Analog signal Digital signal 4∽20mA Analog signal
Here, it is required that during CCS input the "CCS CONTROL REQUEST" signal shall be normally available; otherwise, DEH decides that CCS proper has canceled it and as a result DEH changes from a CCS control mode to a valve position control mode. When DEH receives the "CCS CONTROL REQUEST" signals, we can click the "CCS INPUT" button in the "AUTOMATIC CONTROL" menu of OIS, and the menu will display "CCS INPUT". Under the CCS control mode, the DEH target is equal to the CCS setting value. At this point, the target follows the increase and decrease of CCS setting signals and the actual load also changes accordingly. Under the following conditions, cancel CCS: Operators clicking the "OUT" button in the "AUTOMATIC CONTROL" menu of OIS;
TPC action;; Manual mode; Tripping of oil switch;; Without "CCS CONTROL REQUEST" signals; Runback action. All signals between DEH and CCS connected with hard wires. 4-9
Valve management
The philosophy for valve management is to require that within its whole range of operation a steam turbine can select its mode of regulation as desired and realize a undisturbed switch between throttle control (corresponding to single valve operating mode) and nozzle control (corresponding to sequence valve operating mode). When a throttle steam distribution mode is adopted, the rapid start-stop and varying duty of steam turbine will not go so far as to produce oversized heat stress, so that the unit life loss can be reduced; however, within a normal load range when a nozzle governing variable-pressure operation mode is adopted, the unit has the best economical efficiency and operational flexibility.
During the start, speed raising, grid connection, and with low load phases, in general the throttle control mode, i.e., the "single valve" control mode, is adopted. With this mode, the steam flow enters into the HP control stage in a full circle, which makes the cylinder and rotor be heated and expanded uniformly, and as a result the heat stress resulting from start and the mechanical stress resulting from rotor blade regulation can be effectively lowered. Under a normal power, a nozzle control mode, i.e., the "sequence valve" control mode， is adopted to acquire relatively high thermal efficiency. DEH has valve management functions, that is, it can realize the undisturbed switch between throttle control and nozzle control. Operators are able to select the steam distribution mode of a steam turbine's control valves, and the concrete steam distribution mode depends on the start operation mode of the steam turbine. When the unit's load rises to a certain degree, input power control, and click the "SEQUENCE VALVE" button in the "AUTOMATIC CONTROL" menu of OIS to display "SINGLE / SEQUENTIAL VALVE SWITCHING". About 10 minutes later, the switching is over. After the switching, the load shall be stable. Then switch back to the single valve control mode. The load shall be stable. If input pressure control, and repeat the above process, then after the switching process is over the load shall be stable. If the start is conducted at a hot state or extremely hot state, the sequential valve mode will be adopted forcefully. After the unit throw off the load, it will automatically set the operation mode as sequential valve mode. If at this point you want to
switch back to the single valve mode, grid connection with an initial load is required before the switching between single / sequential valves. 4-10 Overspeed Overspeed control and overspeed protection are available for DEH. 1 Overspeed control 1.1 Load rejection For the time constant of the rotor of a high-capacity steam turbine is commonly very small, the time constant of the cylinder volume is often very large. When load rejection occurs, the rotation speed rises very quickly. If the control only relies on the system itself, the maximum speed may exceed the action speed of the protection system and as a result bring about steam turbine intercepting. For this reason a set of load rejection overspeed limit logic must be set up. If the oil switch is disconnected and load rejection occurs, both DEH hardware and software circuits act simultaneously. The overspeed limit integrated package and the fast solenoid valves of all oil servo motors will act quickly to close CVs and ICVs; meanwhile the target rotation speed and setting rotation speed are changed into 3000r/min. 2 seconds later, all solenoid valves are reset, and the control valves are restored to be under the control of servo valves, and the control turns back to normal speed circuit control. Finally, the rotation speed of steam turbine is stabilized at 3000r/min, so that a rapid grid connection is available after the emergency disappears. 1.2 103% Overspeed Overspeed has a large influence on the life of a steam turbine. Except in the overspeed test, at no time the rotation speed is allowed to exceed 103% (for the max. grid frequency is 50.5Hz, that is, 101%) Under the condition of no overspeed test, once the rotation speed exceeds 103%, the overspeed limit integrated package and the fast solenoid valves of all oil servo motors will act quickly to close CVs and ICVs. When the rotation speed is lower than 103%, all solenoid valves are reset, the control valves are restored to be under the control of servo valves, and the control turns back to the normal speed circuit control. 1.3 Acceleration limit In DEH there also sets up a acceleration limit circuit. When the rotation speeds of two consecutive cycles show a difference of 10r/min, the circuit will close both CV and ICV quickly; when the rotation speed difference is <10r/min, all solenoid valves are reset. 2 Overspeed protection If a steam turbine's rotation speed is too high, the steam turbine will be damaged due to the action of centrifugal stress. Although overspeed limit functions are available for DEH to avoid steam turbine overspeed, in the event of a failure of speed restriction, exceeding the preset speed
will result in tripping, and all the stop valves and control valves will be closed as quickly as possible. For the purpose of safe operation, there set up several layers of overspeed protection in the system: DEH electric overspeed protection 110%; Mechanical overspeed protection In addition, the following tripping functions are also available for DEH: Mannual tripping by operator; Sending out tripping signals by emergency stop cabinet ETS. 3 Overspeed test Operators conduct test operation on the "OVERSPEED TEST" menu of OIS. 3.1 Mechanical overspeed test First shift the overspeed test switch on the "OVERSPEED TEST" menu of OIS from "NORMAL" to "MECHANICAL", then click the " MECHANICAL OVERSPEED TEST" button, and a "TEST PROCEEDING" status will be displayed. Set the target rotation speed as 3360r/min and the speed rate as 100r/min/min for speed raising. When the speed rises so far as to result in tripping, intercept the unit and display both the intercept speed and top speed. After the test is over, reset the top speed, shift the overspeed test switch from the "MECHANICAL" to "NORMAL" to quit the unit from the mechanical overspeed test. 3.2 Electric overspeed test Shift the overspeed test switch on the "OVERSPEED TEST" menu of OIS from "NORMAL" to "ELECTRIC", then click the "ELECTRIC OVERSPEED TEST" button, and a "TEST PROCEEDING" status will be displayed. Set the target rotation speed as 3310r/min and the speed rate as 100r/min/min for speed raising. When the rotation speed rises to exceed 110%, the overspeed protection system acts, intercepting the unit and displaying the intercept rotation speed and top speed. After the test is over, reset the top speed, shift the overspeed test switch from the "ELECTRIC" to "NORMAL" to quit the unit from the Electric overspeed test. 4-11 Valve activity test When a unit is in normal operation, activity tests to check MSVs, RSVs, CVs, and ICVs can be conducted regularly to avoid jamming of these admission valves. Activity tests can be conducted for CVs and SVs respectively. Permissive conditions for valve activity test: All SVs are full open;
Non CCS mode; Automatic mode. On the OIS menu, enter into the "VALVE TESTING" menu, shift the test switch from "TESTING PERMIT" to "TESTING", click the button of the valve for activity test and begin the valve activity test. At this point the valve begins to be closed with a certain speed rate. When the closing reaches 85% opening extent, the valve reopens the position prior to testing. The test is over. After the activity test is over, shift the test switch from "TESTING PERMIT" to "NORMAL". 4-12 Spray oil testing When the rotation speed is in the order of 3000r/min, DEH can complete the spray oil extruding test for the centrifugal stop ring of emergency overspeed governor through resetting testing valve combinations, so as to prevent the centrifugal stop ring from jamming due to long-term motionlessness. When an injection test is conducted, first the isolated solenoid valve in an intercepting isolation valve block is powered up, which isolates the emergency tripping device from the system. Then the spray oil solenoid valve of the emergency overspeed governor is powered up, which makes the emergency tripping valve trip. Because the stop valve has been isolated from the system, the unit will not trip. After the emergency tripping device trips successfully, DEH engage it through resetting the solenoid valve. After the latching-on is available, the isolation solenoid valve loses electricity, so the isolation is canceled, the system is restored to normal, and the spray oil test is over. Permissive conditions for spray oil testing: the rotation speed shall be within 2985r/min~3015r/min and all the indicators of the unit are within the testing allowed range. First in the "SPRAY OIL TESTING" menu of OIS change the test switch from "TESTING PERMIT" to "TESTING", and then click the "SPRAY OIL TESTING" button to input spray oil testing. The screen displays that the spray oil testing is in progress: isolation solenoid valve 4YV is electrified; after ZS4 enters into the testing position, it sends out messages; after DEH receives the signals, spray oil solenoid valve 2YV is electrified, injects oil, and flies the centrifugal stop ring; when DEH receives the intercepting signals of ZS2, it judges that the spray oil testing is successful; then spray oil solenoid valve 2YV losses its electricity, the steam turbine generator unit is reset, isolation solenoid valve 4YV losses its electricity, ZS5 returns to normal, and the spray oil testing is over. 4-13 HP tripping solenoid valve testing The HP tripping solenoid valves consist of four solenoid valves, of which two valves are connected in series and the other two valves are connected in parallel. The design is based on a principle of stop for electricity failure, that is, the sole electricity failure of any solenoid valve will not result in the intercept of the unit; therefore, HP tripping solenoid valves can be tested on-line one by one. The test results can be reflected by the action of two pressure switches PS4 or PS5. When a test for 6YV or 8YV is conducted, the middle oil pressure will be lowered, at this point the pressure switch PS4 will send out a message to show that the solenoid valve under testing has valid action; when a test for 7YV or 9YV is conducted, the
middle oil pressure will increase, at this point pressure switch PS5 will send out a message to show that the solenoid valve under testing has valid action.
After the latching-on for the unit is conducted, a HP tripping solenoid valve test can be conducted. Enter into the "TRIPPING SOLENOID VALVE TESTING" menu in the OIS, and change the test switch from "TESTING PERMIT" to "TESTING". Press the "HP INTERCEPT TESTING" button, and then select solenoid valves 6YV, 7YV, 8YV, or 9YV for testing. The positions of the corresponding solenoid valve in the menu will turn red. After the test is over, the red color will disappear. If the testing succeeds, a "SUCCESS" message will display; if the testing fails, a "FAILURE" message will display. 4-14 Valve leak test When the steam turbine runs idle at the rated speed of rotation and the steam pressure of boiler meet some specific conditions, DEH can control the unit for SV leak testing and CV leak testing. When a SV leak test is conducted, all RSVs and MSVs shall be fully closed and the steam turbine's rotation speed shall be lowered quickly. DEH works out an acceptable rotation speed according to the current main stream pressure and confirms that the rotation speed of the unit can be lowered below the above acceptable rotation speed, by means of which it decides whether the SV is tightly closed. When a CV leak test is conducted, all CVs and ICVs shall be fully closed and the steam turbine's rotation speed shall be lowered quickly. DEH works out an acceptable rotation speed according to the current main stream pressure and confirms that the rotation speed of the unit can be lowered below the above acceptable rotation speed, by means of which it decides whether the CV is tightly closed. Permissive conditions for valve leak testing: automatic mode; latching-on available for the steam turbine; rotation speed within 2985r/min~ 3015r/min; tripping of oil switch; in the "LEAK TEST" menu in the OIS the test switch is in the "TESTING" position instead of "TESTING PERMIT" position. 1 SV leak test The turbine speed is stabilized at 3000r/min. In the "LEAK TEST" menu in the OIS, click the "SV TESTING" button, and the button displays "TESTING PROCEEDING" and the color is red. The control mode changes from "AUTOMATIC" to "MANUAL", all SVs are closed, and the rpm drops. Display the steam turbine race time record. 2 CV leak test The turbine speed is stabilized at 3000r/min.. In the "LEAK TEST" menu in the OIS, click the "CV TESTING" button, and the button displays "TESTING PROCEEDING" and the color is red. The control mode changes from "AUTOMATIC" to "MANUAL", all CVs are closed, and the rpm drops. Display the steam turbine race time record. 3 When the rotation speed reaches the acceptable value, click the "OFF TEST" button to
terminate the leak test. After the test is over, the unit trips for shutdown and restart is required. 4-15 Automatic limit function DEH is featured by automatic limit function, which is used to keep the power, throttle pressure or valve position within certain limits. DEH can set up the maximum and minimum load limits to limit the generator's developed power. The value is given by the operator in the OIS. When the difference between the measured power and given power exceeds the predeterined value, DEH automatically cancels the power control loop and changes into a valve position control mode to ensure the safety of the unit. DEH also has low throttle pressure protection control function (TPC function). When the throttle pressure drops to the set value (set by operator throught OIS), the throttle pressure limit loop is brought into operation, outputting instructions to reduce steam valve opening so as to limit load and help the boiler to restore its throttle pressure as quickly as possible. At this point, the power control circuit is automatically cancelled. DEH can also set up a maximum valve position limit to restrict the steam turbine's valve position within a certain range. The value is set by the operator in the OIS. 1 High load limit Operators can set up the high load limit in the "AUTOMATIC LIMIT" menu in the OIS (20~ 330MW) to ensure that the DEH setting value is always smaller than the limit. After the system is powered on, the high load limit is automatically set up as 330MW. If at this point the load is higher than the limit, it will be automatically reduced to the limit. 2 Low load limit Operators can set up the low load limit in the "AUTOMATIC LIMIT" menu in the OIS (0~ 20MW) to ensure that the DEH load is always greater than the limit. After the system is powered on, the low load limit is automatically set up as 3MW. 3 Valve position limit Operators can set up the valve position limit in the "AUTOMATIC LIMIT" menu in the OIS within (0~120)%, and after the system is powered on, the limit will be automatically set up as 120%. 4-16 Runback When somec equipment failures of main and auxiliaries occur, DEH and DCS interface can quickly release part of or the whole load. According to the scale and importance of equipment failure (decided by DCS), DEH can receive three grades of runback instructions (digital signals, conncected by hardwire), and each grade of
quick release instructions correspond to different target load value and quick release speed rate. When a runback acts, DEH automatically cancels CCS control and power control and directly reduces the valve positions of all valves to ensure the rapidity of action. As per the size of failure, runback can be divided into three grades, which are triggered by the three on-off input signals of runback 1#, 2#, and 3#'s respectively. The lower limits of runback 1#, 2#, and 3# are 75%, 50%, and 25% respectively, and the dropping load rates are 25%/min, 50%/min, and 75%/min respectively. When the required conditions are are met, click the "RUNBACK" option in the "AUTOMATIC CONTROL" menu in the OIS, and set it up as “IN”, as a result the quick release function is input. With the quick release function being input, when there generates a quick release signal, the "target" signal will be decreased with a scheduled speed until the signal disappears or the "target" value is decreased to the lower limit value of the corresponding grade. Operators can cancel the function in the OIS. That is, in the "AUTOMATIC CONTROL" menu in the OIS, click the "RUNBACK" option, and set it as "cancel", and as a result the quick release function will be out of service. When the runback acts, the power control and CCS control will be automatically cancelled. 4-17 Manual control When DEH is just powered on, it first enters into a manual mode. If possible, it can be switched to an automatic mode through the instructions sent out by operators. Under the automatic mode, if possible, it can be switched back to a manual mode through the instructions sent out by operators. The switching from a low level to a high level cannot be achieved without operator command, while the switching from a high level to a low level can be completed automatically or by operating instructions. If the automatic part fails, the manual mode shall be adopted. If one of the following cases occurs, the system will exit from the automatic mode. Control processor halting; SV leak test; CV leak test; Software diagnosis abnormality. If there are no the above cases, the valve position limit fails to act, and the difference between the main valve position setting and its reference is within (-2, 2)%, then inputting an automatic mode is allowed. Under a manual mode, the valve positions of the six CVs and ICVs are increased or decreased accordingly as per the instructions of the valve position fluctuation button.
4-18 Steam turbine tripping The steam turbine tripping can be achieved either mannually or through the “TRIP” button on the electric board. The action of the tripping solenoid valve makes the steam turbine trip. At this point in the "AUTOMATIC CONTROL" menu in the OIS a steam turbine "SWITCH OPEN" status is displayed; meanwhile, all valves are closed. 4-19 Parameter monitoring and recording DEH can consecutively collect and process all the signals related to the control and protection of steam turbine generator unit, and display the results in the CRT of the OIS in groups or in the form of bar graph and tendency chart. All the process points can be tabled and recorded and printed. Each operation menu in the OIS tries to be illustrative and distinct, and operation instructions are available for the important operations. 4-20 ATC control ATC refers to automatic turbine control, which means that, with the least manual intervention, DEH conducts an automatic control over the steam turbine by controlling its rotation speed from hand-turning speed, through synchronous grid connection speed, and finally to the full load speed. ATC control is based on the thermal stress calculation of rotor and directed toward the improvement of rotor life. With the base and aim, the acceleration rate, load raising rate, warm-up point, and warm-up time are determined. When some non-key signals are lost, ATC control can proceed over these signals. When an anomaly occurs, ATC control can either hold on or exit, till the anomaly disappears. 5 Installation and debugging The correct installation and careful debugging of DEH on site is an important step to ensure that it can be smoothly put into service. The installation and debugging on site includes the following steps: Arrival unpacking; Equipment installation; System ground; Power supply; Onsite signal connection; Onsite debugging. 5-1 Arrival unpacking
The on-site unpacking acceptance check for a DEH installation shall be conducted on an open platform with enough carrying capacity. Excessive vibration shall be avoided for the cabinet and the many devices in OIS and EWS, so they shall be handled with care. Lifting lugs shall be used for the hoisting of cabinet. Special attention shall be given to the acceptance check for boards: 1 Use electrostatic prevention sacks. Prior to installation, it is preferred that the board be placed in the electrostatic prevention sacks. Keep these electrostatic prevention sacks for future use. 2 Avoid contacting circuits by hand. 3 Ensure that all the devices connected with boards are correctly earthed. 4 Use non-electrostatic dust collectors to remove dust on boards. During unpacking of board, immediately inspect the boards to make certain whether there are problems during transportation. If there is damage, inform the manufacturer as quickly as possible. 5-2 Installation 1 Installation environment With special DEH operating room, without strong ElectroMagnetic Interference; Proper ambient temperature and humidity; Dust in the air meeting related national standards; Fire Protection available. 2 Cabinet installation Install the cabinet on a level ground. Fasten the cabinet to the ground with bolts or directly weld it on the pre-buried strips. Attention: if there is arc welding within a range 3.05m away from the cabinet, the power cord must be cut off, and the boards shall be pulled out from the slots in the backboards, and close the cabinet gate tightly. If this prompt is ignored, board damage will occur. 3 Installation of SUN workstation According to the installation requirements, lay the communication cables, CRT cables, and keyboard cables. Put the side of the workstation with a floppy drive face oneself and the side with terminals upwards, gently push it into the MMS slot, and confirm that the workstation has been in the slip stop bayonet of the slot. Connect all cable terminals with the workstation at one time, fix them by screwdrivers, and finally plug a terminator in the SCSI equipment.
4
Installation of workstation modules
According to the system installation drawings, first make certain which cabinet and where in the cabinet the workstation modules will be installed (in general, the cabinet slot for workstation module installation is called MS slot). According to the installation requirements, lay cables, and installed the sockets of cable terminal in the corresponding MS slots. Push the modules into the corresponding slots and fix them with bolts. 5-3 System ground The DEH control system needs a complete and proper ground system, because a good ground system can effectively inhibite the external interference, reduce the equipment idle hours, and thus protect both equipment and personal safety. The I/A Series system also needs a complete and proper ground system, because a good ground system can effectively inhibite the external interference, reduce the equipment idle hours, and thus protect both equipment and personal safety. An independent earthing pile must be provided for the I/A system with earth resistance less than 1 ohm. The security protection ground, AC supply ground, and internal signals' logic ground of I/A system shall be connected to the groud pile. Any non I/A equipment grounding cannot be connected with the ground pile. 5-4 Power supply connection Safety (both human and equipment) is the top priority of a power-supply distribution system. After the safety is met, the reliability of the system shall also be met, which includes correctly estimating power load, insulation, and line conditions, so that the interference can be eliminated, the protection system can avoid the damage from poweroff, swing, and overload, and the estimated system expansion can be conducted. Power supply installation According to the user guidance, calculate the loads of the complete appliance, including OIS and EWS, and take into consideration the limited expansion in the future. According to standard ANSI/NFPA70, select AC power conductors and linear diameters. Main power supply must be exclusively used for I/A series installations and related installations. In an industrial environment, the quality of power supply is relatively poor, so a discrete actuating system such as insulating transformer or UPS shall be available to provide power supply for the installation. Main power supply requirements:
Voltage: 220AC±10%； Frequency: 50Hz±1Hz 5-5 External signal connection Attention: Great attention must be paid to the installation of DEH and the connection of external signals, for which a rational design and arrangement must be available. The installation of cable has requirements on cable trench, route channel, and cable guide. When installation and wiring is conducted, the atmospheric environment such as temperature, humidity, and erosion must be taken into consideration. The electrical noise and signal level determine that space, quantity, and shielding measures must be taken into consideration for cable trench and cable guide. When cable wiring is conducted, attentions must be paid to the voltage range, signal characteristics, and signal categories. 1 Analog signal cable Twisted-pair-line shielded cables are adopted. The cable has a specially good effect in the inhibition of electromagnetic coupling. All the shield layers must be insulated from other shield layers electrically. In the DEH cabinet the shield layer is grounded, and the common bus in the cabinet is suitable for the onsite signal shield layer and connected here for joint grounding. For the metal cable guides and cable trenches sealed on site used for cable placing, if possible, a special cable trough shall be designed to place analog signal cable. 2 Thermocouple input signal It is required that the conductor metal in the dedicated cables or cables with continuation shall be the same as or similar to the thermocouple, because in this way the electric potential difference resulting from the connection of different metals can be reduced to the minimum. During the transmission of thermocouple signal, there shall be no break points, switches, or connection points in the conductors, all thermocouple signals must be shielded, and different shield layers must be insulated with each other. 3
Hot resistance input signal
The resistance of all conductors connected with hot resistance must be equal, and the resistance of the cable from the site to the cabinet must meet the limits of the input board. 4
Connection of digital signal
Do not install the onsite contact points of DC or AC into the same cable. If in a cable there are only DC signals, either twisted-pair shielded cables or sole shielded cables can be adopted. 5-6 Testing and debugging Before an installation is put into service on site, it is necessary to conduct full-scale testing and debugging for all parts of the system, especially after a long haul, power plant installation and
external wire connection. As a result the items suggested by the chapter shall be strictly tested and debugged one by one. Primarily as follows: Wire connection check; Transmitter and external signal check; Power ground testing; System function check. 1
Wire connection check Long haul and power plant assembly may result in some loosening of the wire and cable connection in the Control cabinet of DEH; therefore, prior to signal detection and debugging a connection check is necessary. The connection for the installation can be divided into four parts:
1.1
For the connections between cabinets or within a cabinet, check them one by one according to the interior connection drawings provided by the manufacturer, and fasten all the loosened terminals.
1.2 Cable check: A cable shall be intact, both ends of a signal wire in the cable shall be well conducted, and the insulation between conductors or between a conductor and its cable shield layer shall be good; otherwise, the cable shall be replaced. Check whether the redundant cores and shield layers of all cables are grounded in the control board according to the grounding requirements and whether the grounding is good or not. The other ends of the redundant cores and shield layers shall be insulated against ground. 1.3 Check whether all cables are correctly connected. 1.4 According to the cabinet terminal connection diagram, check whether the external signal wires are correctly connected. 1.5 Check whether the original wire connection in the cabinet is loosened, and fasten the loosened connecton based on terminal numbers. Check whether the welding points in the cabinet are reliable, and whether there is break in soldering. 2
Transmitter and external signal testing
Before all the control and monitoring parameters of DEH are sent into the installation, they are tested by the transmitter; therefore, whether the transmitter can work normally has a direct influence on the reliability of the system. So prior to being put into service, the transmitter shall be checked and calibrated in accordance with the measurement range in the signal list. With regard to the external check, it primarily means to check whether the onsite digital signals match the actual conditions. As per the actual on-site conditions, conduct some simulation to verify the input/output digital signals.
3
Power supply and earth conductor check Before power-on, be sure to check the installation connection of power supply and earth conductors thoroughly. Equipment required are as follows: Universal instrument: for voltage and current measurement; Earth resistance tester: for the measurement of the resistance to ground of grounding electrode; Connection tester: for checking whether the connection is right; Power-supply monitor: for recording the voltage, current, temperature, humidity, radio wave frequency, and nodal closing of AC/DC.
3.1 Grounding electrode check The impedance of grounding electrode shall be tested prior to the power-up of the installation or once a year. In order to test the electrode impedance, an earth resistance tester is required, and the impedance of the earthing resistor shall be less than 5 ohm. Otherwise, check the earth conductor connection and the connection between grounding electrode and power grid. 3.2 Power supply measurement Power supply measurement includes current testing, voltage testing, and impedance testing. Current testing: Use an amperemeter to measure and record the related effective values of current, including the currents of the wires under voltage, earth conductors, and zero conductors in the power-supply distribution panels and cabinets. Impedance testing: Measure the input impedance of the ground leads or zero conductors. The smaller the input impedance is, the safer the equipment is. 3.3 Shield layer check The check of shield layer can be conducted in cabinets. If the installation is not powered up, first disconnect the DC earthed conductors, and then conduct the following three tests: 3.3.1 Measure the impedance between the cabinet and the insulated common ground conductor, which shall be less than 1 ohm; if it is greater than 1 ohm, the related connections and system connection shall be checked. 3.3.2 Measure the impedance between the cabinet frame and the DC ground strap, which shall be greater than 1 mega ohm. 3.3.3 If the measurement of step 2 is less than 1 mega ohm, the common ground conductors
between the cabinet under measurement and the other cabinets shall be disconnected. Then repeat the measurement until the error is detected. The probable causes resulting in the above problems are as follows: short-circuit of the onsite shield layer and the ground, or improper installation, or damaged wire connection, or different ground for the I/O signals connected with DEH. Tips: it is preferred to check a shield layer before the installation is powered up or during maintenance downtime. When checking, be sure to turn off the power. Never conduct such checking when the installation is controlling the unit.
5-7 System function check Before the installation is put into service, a powered action test is required to check whether there are hardware and software faulures and whether the system functions are normal, so that the installation can be put into service normally. 1 Connecte the DEH installation to form a complete DEH system. 2 Conduct an electrified test for the DEH installation. Referring to Chapter 4, check it item by item, and ensure that the DEH system can pass all the tests as follows: 2.1 Close the power switch, the indicator gage is normal, and the indicator lights of cabinet boards are normal. 2.2 Close the main power switch of OIS, and close the switch on CRT. Several minutes later, the menu displays normally, and all board indicator lights are normal. 2.3 Start the unit under the automatic, manual, and ATC modes respectively, operate it as per operating standards, and the operation is normal. When operating under an automatic mode, the following functions are normal: Speed control; Automatic synchronization; Power control loop; Frequency adjustment control; CCS control loop; Load limitation; RUNBACK； Single / sequential valve mode switching; TPC protection; Valve position limit; MSV and CV activity tests; RSV and ICV activity tests;
Normal spray oil testing; Normal overspeed test; HPT intercept testing; Valve calibration A servoboard and its corresponding valve's LVDT shall have a certain linear relationship, which makes the control system control CVs and ICVs through the servoboard. In case of the following conditions, valve calibration is required: Prior to unit start; Replaced servoboards and LVDT; After normal maintenance; Valve LVDT has been disassembled; Due to possible temperature drift of LVDT, regular valve calibration is required. After re-download the configuration software. 6 Fault diagnosis and analyses During the running of DEH, ,DEH conducts regular on-line self-diagnosis, through which the failures are alarmed, displayed, and printed, so that the hot control personnel can conduct on-line or off-line maintenance aiming at the problems. Regular maintenance and overhaul is necessary for a long and steady operation of DEH system. 6-1 On-line self-diagnosis During operation, DEH will conduct self testing and diagnosis for its important hardware units and I/O signals. If any problem is found, alarm displaying and report printing will be conducted. 1
Rotation speed channel diagnosis and treatment If the rotation speed signals in any of three rotation speed channels are lost, or if the speed setpoint is greater than 200r/min, the rotation speed signal change quickly, then the rotation speed channel has problems. For any of the three rotation speed channels, if when the speed setpoint is greater than 200r/min, its difference from the medium value is greater than 50r/min, then the channel has problems. For the three speed measurement boards, if any one has problems in its microprocessor, then the rotation speed board has problems. For single-channel failure, ,OIS only displays the number of the failed channel.
When two channels fail or when the difference between the setting value of rotation speed and the actual speed is greater than 500r/min, rotation speed system failure signals will be generated, which will result in turbine trip signals. 2
System monitoring Start the OIS, and then enter into the "SYSTEM MONITORING" menu, through which the whole DEH system (including networks and boards) can be monitored and alarmed. 6-2 Failure analysis and maintenance
While the DEH installation exerts a control, the system also conducts an on-line diagnosis. For the failed cells, alarming, displaying, and printing are available. According to the alarms in both the OIS and the front panel of board, on-line or off-line maintenance can be conducted to make DEH get right as quickly as possible. Block diagrams of onsite diagnosis and maintenance are available for all the boards in the DEH installation. If any board fails, observe the instructions in the user's manual. Some cause analyses and handling methods for onsite signal failure are as follows: 1
Rotation speed channel failure: A short-time single-channel failure will not affect the normal operation of the system. However, if there is a long-time failure or rotation speed system failure, heat engineers shall be employed for maintenance and treatment. First, use an oscilloscope to check whether the rotation speed of the failed channel is normal; if it is abnormal, check whether the wire connection of the speed measurement message sending head is correct and whether the installation meets the requirements. If the rotation speed signals are normal but there are rotation speed channel failures, it is possible that the speed measurement board proper fails.
2
If such parameters as power, throttle pressure, and control pressure do not agree with the actual conditions, the following checks shall be made: First, check whether the signals of the corresponding transmitter are normal and whether the output signal range is in agreement with the designed value; if possible, recheck the transmitter; second, check whether the wire connection of transmitter is correct and reliable; third, check the Analog Input board.
3
As the interface of controller and onsite actuator, a servoboard has complex I/O signals, so whether the servoboard can work correctly determines the reliability of the control.
3.1
The failure occurs during the checking, adjustment, and start of a servo board is called an off-line failure. The causes may be incorrect or incomplete board installation and checking. The following describes the signals of servo board and LVDT. Servoamplifiers do not have servo drive signals: if the drive current signals of the servoboard are correct, check the cable; if the cable has no problems, replace the servo valve. The primary of LVDT do not have drive signals: If the drive signals of the servoboard is
correct, check the cable outputting to LVDT; if the cable has no problems, replace LVDT. The secondary of LVDT has no response output: Change the current output of the servoboard, the voltage difference of the two secondaries of LVDTshall change; if there is no variation, check the connecting cable; if the cable has no problems, replace LVDT. 3.2
The failure occurs during the operation of a servoboard is called an on-line failure. The failure occurring during operation seldom results from connection (with regular checking); in general, the reason is that there are faults in the cabinet interior or sub boards. So the faults can be determined in accordance with the status of the indicator lights on the boards. If there are actuator displacement alarm signals, check the primary or secondary of LVDT. If the primary excitation voltage is less than 1.0VRMS, then the primary of LVDT has failures; if it is greater than 1.0VRMS, check the secondary voltage of LVDT; if the secondary has no sine wave output, then the secondary coil has problems; if both secondary outputs are correct, check other parts.
7 Measuring point list of DEH 1 DI signals No.
1 2 3
Signal name HP
Signal source oil Site proximity switch PS1
safety
Terminal number
Remarks
120014-1(cs,+)
Input
establishment 1 HP
different
safety
oil Site proximity switch PS2
120015-1(cs,+)
oil Site proximity switch PS3
120016-1(cs,+)
establishment 2 HP
safety
establishment 3
4
HP tripping test pass PS4
Site proximity switch PS4
220018-1(cs,+)
5
HP tripping test pass PS5
Site proximity switch PS5
220018-2(cs,+)
6 7 8 9 10
breaker Site travel switch ZS1
120014-5(cs,+)
Emergency breaker at a Site travel switch ZS2
120016-5(cs,+)
Emergency latching-on reset tripping position
Manual tripping position Site travel switch ZS3
120017-1(cs,+)
status Isolation valve at a testing Site travel switch ZS4
220017-5(cs,+)
position Isolation valve at a normal Site travel switch ZS5
220017-6(cs,+)
position
11
Synchronous input
Synchronism installation
120017-5(cs,+)
12
Synchronous increase
Synchronism installation
120017-6(cs,+)
13
Synchronous decrease
Synchronism installation
120017-7(cs,+)
Generator
Electric
TB2-(30/34)
Tripping of oil switch
Electric
TB2-(29/33)
Generator testing (pseudo
Electric
120015-5(cs,+)
14 15 16
grid
connection
grid connection)
17
Manual shut-down
Electric board
TB3-(65/66)
18
Switch openning of ETS
ETS→DEH
120017-2(cs,+)
19
Hand-turning input
Turning gear
120016-6(cs,+)
20
Runback 1#
CCS
120014-2(cs,+)
21
Runback 2#
CCS
120015-2(cs,+)
22
Runback 3#
CCS
120016-2(cs,+)
23
CCS control request
CCS
120015-7(cs,+)
24
MSV1 full close
On site
120014-3(cs,+)
boards
from DI
25
MSV2 full close
on site
120015-3(cs,+)
26
RSV1 full close
on site
120016-3(cs,+)
27
RSV2 full close
on site
120017-3(cs,+)
28
MSV1 full open
on site
120014-4(cs,+)
29
MSV2 full open
on site
120015-4(cs,+)
30
RSV1 full open
on site
120016-4(cs,+)
31
RSV2 full open
on site
120017-4(cs,+)
32
MSV1 85% travel
on site
220018-3(cs,+)
33
RSV1 85% travel
on site
220018-4(cs,+)
34
RSV2 85% travel
on site
220018-5(cs,+)
1# HP exhaust steam
on site
220021-5(cs,+)
on site
220021-6(cs,+)
35 36
valve full close 1# HP exhaust steam valve full open
37
PWV full open
PWV
220017-1(cs,+)
38
PWV full close
PWV
220017-2(cs,+)
39
VV full open
VV
220017-3(cs,+)
40
VV full close
VV
220017-4(cs,+)
Lower by-pass system
by-pass system
224121-1(cs,+)
by-pass system
220021-2(cs,+)
by-pass system
220021-3(cs,+)
by-pass system
220021-4(cs,+)
servo valve controller
220016-1(cs,+)
internal signal
servo valve controller
220016-2(cs,+)
internal signal
CV1 servoboard failure
servo valve controller
220016-3(cs,+)
internal signal
CV1
servo valve controller
220016-4(cs,+)
internal signal
CV2 servoboard failure
servo valve controller
220016-5(cs,+)
internal signal
CV2
servo valve controller
220016-6(cs,+)
internal signal
CV3 servoboard failure
servo valve controller
220016-7(cs,+)
internal signal
CV3
servo valve controller
220016-8(cs,+)
internal signal
servo valve controller
220016-9(cs,+)
internal signal
41 42 43 44 45 46 47 48 49 50 51 52 53
full close Lower by-pass system Manual/Automatic Higher by-pass system full close Higher by-pass system Manual/Automatic MSV2
servoboard
failure MSV2
calibration
in
progress calibration
in
progress calibration
in
progress calibration
in
progress CV4 servoboard failure
54 55 56 57 58
CV4
calibration
in
servo valve controller
220016-10(cs,+)
internal signal
ICV1 servoboard failure
servo valve controller
220016-11(cs,+)
internal signal
ICV1
servo valve controller
220016-12(cs,+)
internal signal
ICV2 servoboard failure
servo valve controller
220016-13(cs,+)
internal signal
ICV2
servo valve controller
220016-14(cs,+)
internal signal
Signal destination
Terminal No.
Remarks
on site 1YV
TB4-(69/70)
R21 solenoid
injection solenoid valve
on site 2YV
TB4-(71/72)
R22 solenoid
mechanical
on site 3YV
TB4-(22/23)
R1 solenoid
isolated solenoid valve
on site 4YV
TB4-(73/74)
R23 solenoid
OSP overspeed solenoid
on site 5AYV
TB4-(56/57)
R16 solenoid
on site 5BYV
TB4-(58/59)
R17 solenoid
solenoid
on site 6YV
TB4-(25/26)
R2 solenoid
solenoid
on site 7YV
TB4-(29/30)
R4 solenoid
solenoid
on site 8YV
TB4-(27/28)
R3 solenoid
solenoid
on site 9YV
TB4-(31/32)
R5 solenoid
on site 10YV
TB4-(33/34)
R6 solenoid
on site 11YV
TB4-(35/36)
R7 solenoid
progress calibration
in
progress calibration
in
progress
2 DO signals No
1 2 3 4 5 6 7 8 9 10 11 12
Signal name Turbine
latching-on
solenoid valve shutdown
solenoid valve
valve 1 OSP overspeed solenoid valve 2 HP
tripping
valve 1 HP
tripping
valve 2 HP
tripping
valve 3 HP
tripping
valve 4 MSV2 tripping solenoid valve MSV1 tripping solenoid valve
13
CV1 fast solenoid valve
on site 12YV
TB4-(41/42)
R10 solenoid
14
CV2 fast solenoid valve
on site 13YV
TB4-(43/44)
R11 solenoid
15
CV3 fast solenoid valve
on site 14YV
TB4-(45/46)
R12 solenoid
16
CV4 fast solenoid valve
on site 15YV
TB4-(47/48)
R13 solenoid
17
ICV2 fast solenoid valve
on site 16YV
TB4-(51/52)
R14 solenoid
18
ICV1 fast solenoid valve
on site 17YV
TB4-(53/54)
R15 solenoid
19 20
RSV2 tripping solenoid
on site 18YV
TB4-(37/38)
R8 solenoid
on site 19YV
TB4-(39/40)
R9 solenoid
valve RSV1 tripping solenoid valve
21
RSV2 test solenoid valve
on site 20YV
TB4-(61/62)
R18 solenoid
22
RSV1 test solenoid valve
on site 21YV
TB4-(63/64)
R19 solenoid
23
MSV1 test solenoid valve
on site 22YV
TB4-(65/66)
R20 solenoid
24
CCS control input
CCS
TB6-(9/10)
R42 solenoid
25
cold start
to by-pass controller
TB6-(23/24)
R47 solenoid
26
warm start
to by-pass controller
TB6-(25/26)
R48 solenoid
27
hot start
to by-pass controller
TB6-(27/28)
R49 solenoid
28
extremely hot start
to by-pass controller
TB6-(29/30)
R50 solenoid
29
IP cylinder start
by-pass controller
TB6-(31/32)
R51 solenoid
30
cylinder switching
by-pass controller
TB6-(33/34)
R52 solenoid
31
Open PWV
PWV
TB6-(15/16)
R43 solenoid
32
Close PWV
PWV
TB6-(17/18)
R44 solenoid
33
Open VV
VV
TB6-(19/20)
R45 solenoid
34
Close VV
VV
TB6-(20/21)
R46 solenoid
35
DEH tripping
ETS
TB6-(1/2)
R38 solenoid
36
HP tripping test 6YV
ETS
TB6-(35/36)
R53 solenoid
37
HP tripping test 7YV
ETS
TB6-(37/38)
R54 solenoid
38
HP tripping test 8YV
ETS
TB6-(39/40)
R55 solenoid
39
HP tripping test 9YV
ETS
TB6-(41/42)
R56 solenoid
40
OPC action
DEH relay cabinet
R40 solenoid
internal signal
41
overspeed test permit
DEH relay cabinet
R41 solenoid
internal signal
42
load greater than 15％
DEH relay cabinet
R39 solenoid
internal signal
43
Single calibration permit
servo valve controller
220018-15(c, k)
internal signal
44
Double calibration permit
servo valve controller
220021-16(c, k)
internal signal
45
MSV2 check begin
servo valve controller
220021-9(c,k)
internal signal
46
CV1 check begin
servo valve controller
220021-10(c,k)
internal signal
47
CV2 check begin
servo valve controller
220021-11(c,k)
internal signal
48
CV3 check begin
servo valve controller
220021-12(c,k)
internal signal
49
CV4 check begin
servo valve controller
220021-13(c,k)
internal signal
50
ICV1 check begin
servo valve controller
220021-14(c,k)
internal signal
51
ICV2 check begin
servo valve controller
220021-15(c,k)
internal signal
3 AI signals No
Signal name
Signal source
Terminal No.
Remarks
1
throttle pressure (left)
on site
120011-1(+iP,i+)
0～25MPa 4～20mA
2
throttle pressure (right)
on site
120012-1(+iP,i+)
0～25MPa 4～20mA
3
CV steam pressure
on site
120005-2(+iP,i+)
0～25MPa 4～20mA
4
Stem pressure before ICV (left)
on site
220001-1(+iP,i+)
0～6MPa 4～20mA
5
Stem pressure before ICV (right)
on site
220001-2(+iP,i+)
0～6MPa 4～20mA
6
Stem pressure after ICV (left)
on site
220001-3(+iP,i+)
0～6MPa 4～20mA
7
Stem pressure after ICV (right)
on site
220001-4(+iP,i+)
0～6MPa 4～20mA
8 9
Exhaust
pressure
of
HP
cylinder Exhaust
pressure
of
intermediate pressure cylinnder
on site on site
120006-2(+iP,i+) 120006-3(+iP,i+)
0～6MPa 4～20mA 0～6MPa 4～20mA
10
Steam condenser vacuum
on site
120004-3(+iP,i+)
-0.1～0MPa 4～20mA
11
Lubricating oil pressure
on site
120011-2(+iP,i+)
0～0.25MPa 0～100％
12
Fire-resistant oil pressure
on site
120012-2(+iP,i+)
0～0.25MPa 0～100％
13
Generator power 1
Electric
120004-1(i+,i-)
0～300MW 4～20mA
14
Generator power 2
Electric
120005-1(i+,i-)
0～300MW 4～20mA
15
Generator power 3
Electric
120006-1(i+,i-)
0～300MW 4～20mA
16
CCS instructions
CCS
120004-2(i+,i-)
0～100% 4～20mA
17
Eccentricity
TSI
120013-1(i+,i-)
0∼100μm 4∼20mA
18
Axial displacement
TSI
220015-1(i+,i-)
-2∼2mm 4∼20mA
19 20 21 22 23 24 25 26 27 28 29
Expansion difference between HP and IP cylinders Expansion difference of LP cylinder Thermal expansion of HIP cylinders (left) Thermal expansion of HIP cylinders (right) 1 ＃
bearing
vibration
(X-direction) 1 ＃
bearing
vibration
(Y-direction) 2 ＃
bearing
vibration
(X-direction) 2 ＃
bearing
vibration
(Y-direction) 3 ＃
bearing
vibration
(X-direction) 3 ＃
bearing
vibration
(Y-direction) 4 ＃
bearing
(X-direction)
vibration
TSI TSI TSI TSI TSI TSI TSI TSI TSI TSI TSI
220015-2(i+,i-) 220015-3(i+,i-) 220001-5(i+,i-) 220001-6(i+,i-) 220001-7(i+,i-) 220001-8(i+,i-) 220002-1(i+,i-) 220002-2(i+,i-) 220002-3(i+,i-) 220002-4(i+,i-) 220002-5(i+,i-)
-5∼8mm 4∼20mA 0∼17mm 4∼20mA 0∼50mm 4∼20mA 0∼50mm 4∼20mA 0∼400μm 4∼20mA 0∼400μm 4∼20mA 0∼400μm 4∼20mA 0∼400μm 4∼20mA 0∼400μm 4∼20mA 0∼400μm 4∼20mA 0∼400μm 4∼20mA
30 31 32 33 34
4 ＃
bearing
vibration
(Y-direction) 5 ＃
bearing
vibration
(X-direction) 5 ＃
bearing
vibration
(Y-direction) 6 ＃
bearing
vibration
(X-direction) 6 ＃
bearing
vibration
(Y-direction)
TSI TSI TSI TSI TSI
220002-6(i+,i-) 220002-7(i+,i-) 220002-8(i+,i-) 220003-1(i+,i-) 220003-2(i+,i-)
0∼400μm 4∼20mA 0∼400μm 4∼20mA 0∼400μm 4∼20mA 0∼400μm 4∼20mA 0∼400μm 4∼20mA
35
1＃ bearing cap vibration
TSI
220003-3(i+,i-)
0∼125μm 4∼20mA
36
2＃ bearing cap vibration
TSI
220003-4(i+,i-)
0∼125μm 4∼20mA
37
3＃ bearing cap vibration
TSI
220003-5(i+,i-)
0∼125μm 4∼20mA
38
4＃ bearing cap vibration
TSI
220003-6(i+,i-)
0∼125μm 4∼20mA
39
5＃ bearing cap vibration
TSI
220003-7(i+,i-)
0∼125μm 4∼20mA
40
6＃ bearing cap vibration
TSI
220003-8(i+,i-)
0∼125μm 4∼20mA
41
fire-resistant oil temperatuere
on site (RTD)
220011-7(i+,i-)
0～100℃
42 43 44 45 46 47 48 49 50 51 52 53
1#
bearing
scavenge
oil
scavenge
oil
scavenge
oil
scavenge
oil
scavenge
oil
scavenge
oil
temperature 2#
bearing
temperature 3#
bearing
temperature 4#
bearing
temperature 5#
bearing
temperature 6#
bearing
temperature 1＃ positioning thrust washer metal temperature 2＃ positioning thrust washer metal temperature 3＃ positioning thrust washer metal temperature 4＃ positioning thrust washer metal temperature 5＃ positioning thrust washer metal temperature 6＃ positioning thrust washer metal temperature
on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD)
220011-1(i+,i-) 220011-2(i+,i-) 220011-3(i+,i-) 220011-4(i+,i-) 220011-5(i+,i-) 220011-6(i+,i-) 220012-1(i+,i-) 220012-2(i+,i-) 220012-3(i+,i-) 220012-4(i+,i-) 220012-5(i+,i-) 220012-6(i+,i-)
0～65℃ 0～80℃ 0～80℃ 0～80℃ 0～80℃ 0～80℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃
54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69
7＃ positioning thrust washer metal temperature 8＃ positioning thrust washer metal temperature 9＃ positioning thrust washer metal temperature 10＃ positioning thrust washer metal temperature 11＃ positioning thrust washer metal temperature 1 ＃ working thrust washer metal temperature 2 ＃ working thrust washer metal temperature 3 ＃ working thrust washer metal temperature 4 ＃ working thrust washer metal temperature 5 ＃ working thrust washer metal temperature 6 ＃ working thrust washer metal temperature 7 ＃ working thrust washer metal temperature 8 ＃ working thrust washer metal temperature 9 ＃ working thrust washer metal temperature 10 ＃ working thrust washer metal temperature 11 ＃ working thrust washer metal temperature
on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD) on site (RTD)
220012-7(i+,i-) 220012-8(i+,i-) 220013-1(i+,i-) 220013-2(i+,i-) 220013-3(i+,i-) 220013-4(i+,i-) 220013-5(i+,i-) 220013-6(i+,i-) 220013-7(i+,i-) 220013-8(i+,i-) 220014-1(i+,i-) 220014-2(i+,i-) 220014-3(i+,i-) 220014-4(i+,i-) 220014-5(i+,i-) 220014-6(i+,i-)
0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃ 0～120℃
70
main steam temperature (left)
on site (TC)
220004-1(i+,i-)
0～600℃
71
main steam temperature (right)
on site (TC)
220004-2(i+,i-)
0～600℃
72
reheat steam temperature (left)
on site (TC)
220004-3(i+,i-)
0～600℃
73 74 75
reheat
steam
temperature
(right) MSV outer wall temperature (left) MSV outer wall temperature (right)
on site (TC) on site (TC) on site (TC)
220004-4(i+,i-) 220004-5(i+,i-) 220004-6(i+,i-)
0～600℃ 0～600℃ 0～600℃
76 77
MSV inwall temperature (left) MSV
inwall
temperature
(right)
on site (TC) on site (TC)
220004-7(i+,i-) 220004-8(i+,i-)
0～600℃ 0～600℃
78
CV steam temperature
on site (TC)
220005-1(i+,i-)
0～600℃
79
HP exhaust temperature
on site (TC)
220005-2(i+,i-)
0～600℃
80
IP exhaust temperature
on site (TC)
220005-3(i+,i-)
0～600℃
81 82 83 84 85 86 87 88 89 90 91 92
HP inside cylinder upper half inwall temperature HP inside cylinder lower half inwall temperature HP inside cylinder upper half outwall temperature HP inside cylinder lower half outwall temperature HIP outside cylinder IP admission upper half inwall temperature HIP outside cylinder IP admission lower half inwall temperature HIP outside cylinder IP admission upper half outwall temperature HIP outside cylinder IP admission lower half outwall temperature HP exhaust outlet upper half inwall temperature HP exhaust outlet lower half inwall temperature IP exhaust outlet upper half inwall temperature IP exhaust outlet lower half inwall temperature
93
MSV2 valve location
94
CV1 valve location
95
CV2 valve location
96
CV3 valve location
97
CV4 valve location
on site (TC) on site (TC) on site (TC) on site (TC) on site (TC) on site (TC) on site (TC) on site (TC) on site (TC) on site (TC) on site (TC) on site (TC) servo
220005-4(i+,i-) 220005-5(i+,i-) 220005-6(i+,i-) 220005-7(i+,i-) 220006-1(i+,i-) 220006-2(i+,i-) 220006-3(i+,i-) 220006-4(i+,i-) 220006-5(i+,i-) 220006-6(i+,i-) 220006-7(i+,i-) 220006-8(i+,i-)
0～600℃ 0～600℃ 0～600℃ 0～600℃ 0～600℃ 0～600℃ 0～600℃ 0～600℃ 0～510℃ 0～510℃ 0～515℃ 0～510℃
valve 220015-4(i+,i-)
internal signal
valve 120004-4(i+,i-)
internal signal
valve 120005-4(i+,i-)
internal signal
valve 120006-4(i+,i-)
internal signal
valve 120011-4(i+,i-)
internal signal
controller servo controller servo controller servo controller servo controller
98
ICV1 valve location
99
ICV2 valve location
servo
valve 120012-4(i+,i-)
internal signal
valve 120013-4(i+,i-)
internal signal
controller servo controller
4 AO Signals No
Signal name
Signal source
Terminal No.
Remarks
1
Steam turbine valve location
CCS
120011-6(o+,o-)
2
MSV2 opening instruction
servo
valve 220015-5(o+,o-)
internal signal
3
CV1 opening instruction
valve 120004-5(o+,o-)
internal signal
4
CV2 opening instruction
valve 120005-5(o+,o-)
internal signal
5
CV3 opening instruction
valve 120006-5(o+,o-)
internal signal
6
CV4 opening instruction
valve 120011-5(o+,o-)
internal signal
7
ICV1 opening instruction
valve 120012-5(o+,o-)
internal signal
8
ICV2 opening instruction
valve 120013-5(o+,o-)
internal signal
controller servo controller servo controller servo controller servo controller servo controller servo controller
5 Other signals No.
Name
Source
Terminal No.
Remarks
1
rotation speed 1
on site →DEH
Bailing 1(15/19)
Reluctance type
2
rotation speed 2
on site →DEH
Bailing 2(15/19)
Reluctance type
3
rotation speed 3
on site →DEH
Bailing 3(15/19)
Reluctance type
4
MSV2 control signal 1
→ on site
TB7-(1/2)
+/-40mA
5
MSV2 control signal 2
→ on site
TB7-(3/4)
+/-40mA
6
LVDT1 first drive signal
→ on site
TB7-(6/15)
1.7kHz,2.2～3.5V
7
LVDT2 first drive signal
→ on site
TB7-(6/15)
1.7kHz,2.2～3.5V
8
LVDT1 secondary feedback 1
on site →DEH
TB7-(7/8)
9
LVDT1 secondary feedback 2
on site →DEH
TB7-(9/10)
10
LVDT2 secondary feedback 1
on site →DEH
TB7-(11/12)
11
LVDT2 secondary feedback 2
on site →DEH
TB7-(13/14)
12
CV1 control signal 1
→ on site
TB7-(18/19)
+/-40mA
13
CV1 control signal 2
→ on site
TB7-(20/21)
+/-40mA
14
LVDT3 first drive signal
→ on site
TB7-(23/32)
1.7kHz,2.2～3.5V
15
LVDT4 first drive signal
→ on site
TB7-(23/32)
1.7kHz,2.2～3.5V
16
LVDT3 secondary feedback 1
on site →DEH
TB7-(24/25)
17
LVDT3 secondary feedback 2
on site →DEH
TB7-(26/27)
18
LVDT4 secondary feedback 1
on site →DEH
TB7-(28/29)
19
LVDT4 secondary feedback 2
on site →DEH
TB7-(30/31)
20
CV2 control signal 1
→ on site
TB7-(35/36)
+/-40mA
21
CV2 control signal 2
→ on site
TB7-(37/38)
+/-40mA
22
LVDT5 first drive signal
→ on site
TB7-(40/49)
1.7kHz,2.2～3.5V
23
LVDT6 first drive signal
→ on site
TB7-(40/49)
1.7kHz,2.2～3.5V
24
LVDT5 secondary feedback 1
on site →DEH
TB7-(41/42)
25
LVDT5 secondary feedback 2
on site →DEH
TB7-(43/44)
26
LVDT6 secondary feedback 1
on site →DEH
TB7-(45/46)
27
LVDT6 secondary feedback 2
on site →DEH
TB7-(47/48)
28
CV3 control signal 1
→ on site
TB7-(51/52)
+/-40mA
29
CV3 control signal 2
→ on site
TB7-(53/54)
+/-40mA
30
LVDT7 first drive signal
→ on site
TB7-(56/65)
1.7kHz,2.2～3.5V
31
LVDT8 first drive signal
→ on site
TB7-(56/65)
1.7kHz,2.2～3.5V
32
LVDT7 secondary feedback 1
on site →DEH
TB7-(57/58)
33
LVDT7 secondary feedback 2
on site →DEH
TB7-(59/60)
34
LVDT8 secondary feedback 1
on site →DEH
TB7-(61/62)
35
LVDT8 secondary feedback 2
on site →DEH
TB7-(63/64)
36
CV4 control signal 1
→ on site
TB7-(68/69)
+/-40mA
37
CV4 control signal 2
→ on site
TB7-(70/71)
+/-40mA
38
LVDT9 first drive signal
→ on site
TB7-(73/82)
1.7kHz,2.2～3.5V
39
LVDT10 first drive signal
→ on site
TB7-(73/82)
1.7kHz,2.2～3.5V
40
LVDT9 secondary feedback 1
on site →DEH
TB7-(74/75)
41
LVDT9 secondary feedback 2
on site →DEH
TB7-(76/77)
42
LVDT10 secondary feedback 1
on site →DEH
TB7-(78/79)
43
LVDT10 secondary feedback 2
on site →DEH
TB7-(80/81)
44
ICV1 control signal 1
→ on site
TB7-(85/86)
+/-40mA
45
ICV1 control signal 2
→ on site
TB7-(87/88)
+/-40mA
46
LVDT11 first drive signal
→ on site
TB7-(90/99)
1.7kHz,2.2～3.5V
47
LVDT12 first drive signal
→ on site
TB7-(90/99)
1.7kHz,2.2～3.5V
48
LVDT11 secondary feedback 1
on site →DEH
TB7-(91/92)
49
LVDT11 secondary feedback 2
on site →DEH
TB7-(93/94)
50
LVDT12 secondary feedback 1
on site →DEH
TB7-(95/96)
51
LVDT12 secondary feedback 2
on site →DEH
TB7-(97/98)
52
ICV2 control signal 1
→ on site
TB7-(101/102)
+/-40mA
53
ICV2 control signal 2
→ on site
TB7-(103/104)
+/-40mA
54
LVDT13 first drive signal
→ on site
TB7-(106/115)
1.7kHz,2.2～3.5V
55
LVDT14 first drive signal
→ on site
TB7-(106/115)
1.7kHz,2.2～3.5V
56
LVDT13 secondary feedback 1
on site →DEH
TB7-(107/108)
57
LVDT13 secondary feedback 2
on site →DEH
TB7-(109/110)
58
LVDT14 secondary feedback 1
on site →DEH
TB7-(111/112)
59
LVDT14 secondary feedback 2
on site →DEH
TB7-(113/114)
68
ETS tripping
ETS→DEH
TB3-(57/60)
DI (to relay loop)
69
ETS tripping
ETS→DEH
TB3-(58/61)
DI (to relay loop)
70 71 72 73 74 75 76 77 78 79 80 81 82
Main 220VDC power supply Electric→DEH (No. 1)
Circuit
breaker 240VDC, 20A
SW5-(1/3)
Auxiliary 220VDC power supply Electric→DEH
Circuit
(No. 2)
SW6-(1/3)
Main 220VDC malfunction alert →DCS “Guang” TB6-(63/64) brand
breaker 240VDC, 20A switching value (normal close)
Auxiliary 220VDC malfunction →DCS “Guang” TB6-(66/67)
switching value (normal
alert
brand
close)
220VAC power supply (No. 1)
Electric→DEH
Circuit
breaker 220VAC，15A
SW1-(1/3) 220VAC power supply (No. 2)
Electric→DEH
Circuit
breaker 220VAC，15A
SW2-(1/3) 220VAC power supply (No. 3)
Electric→DEH
Circuit
breaker 220VAC，15A
SW3-(1/3) 220VAC power supply (No. 4)
Electric→DEH
Circuit
breaker 220VAC，15A
SW4-(1/3) card
cabinet
main
220VAC →DCS “Guang” TB6-(72/73)
malfunction alert
brand
switching value (normal close)
Card cabinet auxiliary220VAC →DCS “Guang” TB6-(75/76)
switching value (normal
malfunction alert
close)
Relay
cabinet
brand main
malfunction alert
220VAC →DCS “Guang” TB6-(78/79) brand
switching value (normal close)
Relay cabinet auxiliary 220VAC →DCS “Guang” TB6-(81/82)
switching value (normal
malfunction alert
brand
close)
Relay cabinet 24VDC loss
→DCS “Guang” TB6-(60/61)
switching value (normal
brand
close)
83
Manual shut down
→SOE
TB6-(51/52)
84
DEH tripping
→SOE
TB6-(53/54)
85
110% action
→SOE
TB6-(55/56)
86
OPC action
→SOE
TB6-(57/58)
87
110% action
→ “Guang” brand TB6-(69/70)
Chapter 3 辅机维护 section1
Specification for Main Body of Steam Turbine and Line Drainage System(N300-16.7/537/537-8)
0-1 Specification for Main Body of Steam Turbine and Line Drainage System 1. System Function The main function of drainage system is to discharge the condensed water in the main body of steam turbine and its line when the assembling unit starts, stops or operates under low load or under abnormal conditions so as to prevent the excess of water from bending the rotor of steam turbine or damaging the internal parts and other serious accidents. 2. Brief Introduction about System 2.1 The drainage system is designed by following the relevant regulations in the “Guidelines for Preventing Excess of Water for Steam Turbines in Power Plants” (ASME TDP-1-1980) and absorbing the successful experiences of relevant drainage system improvements in China. 2.2 According to the responsibility of steam turbine works and the common practice of power stations in China, the responsible range of drainage system includes the drainage of main body of steam turbine and main body line, i.e. the drainage of main steam valve and line between it and the steam turbine, the drainage of each steam extraction check valve and line between it and the cylinder, the drainage of exhaust check valve for HP cylinder and line between it and the HP steam drain, the drainage of HP steam source control station with self sealing vapor lock system, auxiliary steam source control station, valves in the overflow control station, line as well as the mother pipe and branch pieces of steam supply. The details can be found in the drainage diagram of main body of steam turbine and its line (Fig.0-1-1). Other drainages to be connected with the secondary steam separator of main body drainage besides the main body are illustrated by the dotted lines. The drainage line specifications are only for reference. 2.3 The system adopts two side-basket type drainage secondary steam separators that are placed at the two sides of steam condenser casing. Seven drainage manifolds are connected to the secondary steam separator at the steam turbine side for receiving the drainage of main body of steam turbine and its line, the drainage of HP mean steam conduit, re-heat steam conduit and small steam turbine for feed pump, the continuous drainage of LP heater, etc. Six drainage manifolds are connected to the secondary steam separator at the motor side for receiving the drainage of HP and LP heaters during accidents as well as the drainage of
deaerator overflow. 2.4 Pneumatic control cutoff valves, manual cutoff valves and throttle sets are installed on the drainage branch pieces of main body of steam turbine and its line. The manual cutoff valve shall normally be locked or be fully opened by other means. 2.5 The drainage lines in the system diagram adopt different materials depending on different temperatures. When the steam temperature at the drainage point is more than 400℃, alloy steel tube is used. 2.6 The supply range of system includes the main body of steam turbine, drainage throttle set from the main body lines and pneumatic control cutoff valves. Other universal valves, pipes and accessories are supplied by the project. 3. Installation Requirement 3.1 The drainage range of system is as shown in the diagram. Without the agreement of manufacturer, other drainages can not be connected in at will. The drainage branch pieces connected to the manifold shall be connected in the direction of 45°with the center of manifold and the inlet direction shall be the same as the flowing direction. The discharge points of drainage branch pieces shall be oriented to the condenser to ensure smooth drainage. Each drainage conduit shall be connected to the manifold in the sequence of pressure step-down. The conduit with the highest pressure shall be the farthest from the secondary steam separator of drainage to avoid it from being blocked or water from flowing backwards. The welded joints for the straight tube for flowing water and the drainage mother pipe shall be detected with ultrasonic according to JB4730. They shall meet Class 1 to ensure the welding quality to prevent the welding line from cracking when the temperature changes dramatically, which will affect the vacuum of condenser. 3.2 Each drainage conduit shall continuously descend along the drainage flow direction to avoid water accumulation in the line.
3.3 Drainage points shall be located at the low position points of main steam conduit, reheat steam conduit, steam extraction conduit, steam supply conduit with vapor lock, etc. 3.4 The throttle set shall be placed close to the drainage manifold, where shall be easy for removal and cleaning. The inlet and outlet shall not be connected oppositely. 3.5 Drainage bags are recommended for the drainage points of self sealing steam supply control station and steam extraction line. The drainage bag can be made of seamless tube with the same material and its inside diameter shall be smaller than the main conduit one to two levels, but no less than Φ150mm. The length of drainage bag, if calculating from the outside wall of main conduit, shall be no less than 100mm.
4. Control Requirement 4.1 Start-up and Shutdown of Assembling Unit Before the start-up of assembling unit, confirm the condenser working properly and make sure certain vacuum formed. The control system of DEH automatically starts the pneumatic control cutoff valve on each drainage branch piece. When the load is increased to 10%, the pneumatic control drainage valve in the HP section is closed; when the load is increased to 20%, the pneumatic control drainage valve in the MP section is closed; when the load is increased to 30%, the pneumatic control drainage valve in the LP is closed. The DEH provides signals for all the above movements to automatically realize the close of pneumatic control drainage cutoff valves through the interlocking device of auxiliary equipment. The movements can also be displayed with the lights in the control compartment. During the shutdown or the reduction of load, when the load is reduced to 30%, 20% and 10%, the DEH provides signals through the interlocking device of auxiliary equipment to automatically open the pneumatic cutoff check valves in the LP, MP and HP sections. The movements can also be displayed with the lights in the control compartment. Refer to the drainage system part in the diagram of electric monitoring protection system of steam turbine for details. 4.2 When the steam turbine trips to stop due to accidents, each pneumatic control cutoff valve will automatically open. 4.3 When the HP and LP heaters stop working, the relevant drainage pneumatic control cutoff check valves will automatically open. 4.4 When the auto opening fails, the operator can manually and remotely open the pneumatic cut off valves in the control room. 4.5 Air source pressure for pneumatic control cutoff check valve: 0.4~0.7MPa(a). 5. Operation 5.1 The operator much master the handling measures for excess of water in the steam turbine under various working states as well as take quick and specific actions on the preliminary forecast of steam turbine flooding. 5.2 The load point for auto drainage mentioned in 4.1, the power plant can adjust it according to actual operational experience. In particular, when the steam turbine restarts a while after tripping and rejecting the load, the operator must decide according to the actual situation whether the drainage pneumatic control cutoff valves of main steam conduit and HIP cylinder shall be opened and the operation procedures shall be fixed to prevent the boiler heater and main steam line from cooling down dramatically or cause excessive temperature difference between the upper and lower cylinders due to the pressure reduction of main steam system,
etc. 5.3 Use thermometers, thermocouples or other methods regularly to check whether each drainage conduit is obstructed. 5.4 During operation, if the steam turbine is flooded, the cause shall be identified immediately. At the same time, the water source shall be isolated and the accumulated water shall be drained. If the speed is lower than the rated one, the machine shall be stopped immediately; if the speed is at the rated one and the load is carried, the problem shall be handled according to the actual situation. 5.5 During the shut-down for repairing period, the inside of throttle set shall be cleaned to avoid it from being blocked.
6. Test, Inspection and Maintenance 6.1 All the pneumatic control cutoff valves shall be operated for testing purpose each month. Visually inspect the monitor of steam turbine to ensure that the meters for the differential expansion, cylinder expansion, shaft bend, vibration, rotor axial displacement, metal temperature and other are normal with correct readings. 6.2 Use contact thermometers or thermocouples every three months to inspect all the drainage lines to see whether they are blocked. In the meanwhile, check whether the drainage valves are agile and the throttle sets are unobstructed. 6.3 During the shutdown for repairing period, inspect all the pneumatic control cutoff valves, interlocked devices and controllers. All the drainage valves controlled by water signal shall go through the water movement mechanism test. All the throttle sets shall be cleaned. The inside of obstructed lines shall be inspected to ensure smooth drainage. 6.4 Cleaning the throttle set: disassemble the nuts and bolts from the sealing flange, remove the sealing flange and washer, remove the throttle cock with a hexagonal head wrench, flush out the defilement in the throttle hole (Refer to Fig.0-1-2 for the structure of throttle set). 7. Recommendations for Line Drainage in Power Plant 7.1 Drainage cans with water level control valves shall be installed for the reheat cold line, HP line, LP side line and HP inlet steam line for the steam turbine of feed pump. When the water level of drainage can is high, the outlet valve of drainage can will open automatically. The minimum diameter of drainage can shall be no less than Φ150mm. 7.2 A connection conduit of about 250mm long and min. diameter Φ100mm shall be installed for the drainage of reheat hot section line, which is used for gravity drainage under the low load. 7.3 Throttle plates shall be installed according to the requirement in the system diagram for the line drainage in the power plant, which not only ensure smooth drainage for the maximum discharge, but also prevent losing excessive steam.
Drainage Conduit of Main Steam Conduit for No. III HP Regulating Valve
Drainage Conduit of Main Steam Conduit for No. IV HP Regulating Valve
Section 1 Steam Extraction to JG2
Section 2 Steam Extraction to JG2 HP Cylinder
MP Cylinder
LP Cylinder
Cylinder interlayer heating to steam combination box and drainage of inlet tube
Section 3 Steam Extraction to JG1
Condenser
Drainage Secondary Steam Separator II
Drainage Secondary Steam Separator I
Section 4 Steam Extraction to Deaerator and Steam for Plant
Section 4 Steam Extraction to Small Steam Turbine of Feed Pump
Section 5 Steam Extraction to JD4
Steam Supply for Main Steam
Section 6 Steam Extraction to JD3
Reheat Cold Section
A
old 6
LP Cylinder
View B
Auxiliary Steam Source
Drainage Manifold 1
rainage anifold 7
Drainage Conduit C Drainage Manifold 2
lectric Cutoff Valve
Drainage Manifold 5
Drainage Conduit F
Drainage Conduit E
Drainage Conduit B
Drainage Conduit A
To condenser (backup)
To Section 8 steam extraction heater
Drainage Conduit D
Drainage Conduit E
To steam supply for shaft seal of steam turbine of water pump To HP and MP shaft seal
Legend Check Valve
Manual Cutoff Valve
Drainage Line of Power Plant
Drainage Line of Main Body
Steam Line
Drainage Interface
To LP shaft seal
Spray Type Desuperheater
Fig. 0-1-1 Diagram I of Drainage System
section2
N-17750 Condenser Specifications
0-1
N-17750 Condenser Specifications
1 Applications As one of the major auxiliary equipment in a steam turbine, the condenser is primarily used to condense the steam discharged from the steam turbine through recirculated cooling water, establish and maintain the required vacuum state in the turbine discharge space, and recover the clear condensate to feed the boiler. 2 Main characteristic parameters Cooling area
17750m2
Cooling water temperature
26℃
Cooling water pressure
0.35MPa（g）
Cooling water volume
41050 t/h
Steam pressure
6.7 kPa(absolute pressure)
Steam flow
610 t/h
Furthermore, a well installed condenser without water is about 360t weight (including No.7/No.8 LP heaters, a temperature-decreased pressure reducer, and a drain flash tank). During normal running, the water in a condenser is about 310t weight; when the steam chamber is full of water, the water is about 820t weight. 3 Structure overview The condenser is of an all-welded structure consisting of a throat, a shell (including hot well and water chamber), and the sliding and fixed supports at the bottom (as shown in Figure 0-1-1). It is a single-shell dual-flow-path surface condenser. 3.1
Throat
The outside of the throat is welded by 20mm-thick steel plates and the inside is supported by truss, both of which ensure a satisfactory rigidity. In the throat there are composite LP heater, the steam exhaust connection of feed pump turbine, and the temperature-decreased pressure reducer from the turbine by-pass system. The V, VI, VII, and VIII sections of extraction steam pipe of steam turbine as well as the shaft seal backsteam and steam supply pipes go into the condenser from the top the throat, the V and VI extraction steam pipes go out of the
condenser through the throat shell wall, and the VII and VIII sections of extraction steam pipe are connected to the composite LP heater. The insulation design for the extraction steam pipe is based on the heat insulation principle by adopting stainless steel insulation hood, which as a result avoids the defect that when common heat insulating materials are used for insulation the condensate quality is often contaminate by the flaking of heat insulating material. 3.2 Shell and water chamber The shell consists of 20mm-thick steel plates welded together, and is strengthened by interior stand bars, so satisfactory rigidity is available. Cooling water pipes form four groups of pipe bundles in the shell (pipe bundles are arranged in the form of triangle). Cooling water enters into the two groups of pipe bundles in the middle by way of front intake chamber, and turns around through the back chamber, and flows across the front outlet chambers on both sides through the two groups of pipe bundles on both sides, and finally flows out of the condenser. Cooling water turns horizontally in pipe bundles (including back water chamber), which ensures that the water velocity in cooling pipes are even and the heat load is distributed uniformly. At the bottom of each group of pipe bundles, an air cooling zone is set up. Its air extraction pipes find their outlets in the air side space. Surrounding the top of the main condensing zone, there are two rows of cooling pipes, which are Φ25X0.7 titanium pipes, in total 856. In the air cooling zone there are set up 1260 titanium pipes (Φ25X0.7); In the rest of the main condensing zone, there are set up 19336 titanium pipes (Φ25X0.5). Both ends of a cooling pipe are fixed to an end pipe sheet by expanded and welded tube joint, while the end pipe sheet and the shell are integrated into one body by welding. The intermediate pipe sheet is welded to the side plate of the shell through stand bars, and welded to the bottom plate of the shell through vertical stand bars. Within the shell there also set up some collecting plates and steam baffles. Near the pipe sheets of both ends, there are set up sampling tanks, which are used to test the leak proofness between cooling pipe and pipe sheet.
The lower part of the shell is a hot well. In the condenser the hot well and shell are integrated
together. The condensate outlet is arranged at the bottom of the hot well, where there is set up a stilling device. Both the front and back water chambers have an arc structure made of rolled steel plates, which is featured by simplicity, good flowing property, small resistance, slight vibration, and being favorable for water flowing into the cooling pipe. For the purpose of corrosion protection, the inner surface of the chamber contacting sea water is lined with 5mm-thick rubber, which is vulcanized completely. The front water chamber is divided into four independent small chambers, of which the two intake chambers are in the middle, and the outlet chambers are in both sides. The back water chamber is divided into two independent chambers. All pipe sheets are fixed to water chambers by flange connection, which is convenient for water side corrosion protection and cooling pipe replacement.
For the purpose of overhaul and maintenance, manholes are set up in the throat, lower shell, and water chambers. There are also set up air vents and extraction openings on water chamber tops. In the condenser there is set up a water gage, which can display and monitor the water levels in the hot well and water chambers. During field installation, the actual position of hot well water gage can be determined by customer, but the elevation indication must fulfill the design requirements. The installation site of a water chamber water gage also must fulfill the requirements of the drawing. 4
Connection and support pattern
Condenser and turbine discharge openings are connected by using stainless steel expansion joints in the form of flexible connection. The lower part of condenser is supported by non-yielding prop. During operation, the thermal expansion of the condenser is compensated by the corrugated-type expansion joint in the throat. At the bottom there are set up one fixed support and four slide supports. In respect that the self expansion of condenser resulting from the load and working condition variation during operation, sliding supports are adopted for the four corners, with PTFE boards as the sliding plane, and in the middle of condenser bottom fixed supports are adopted to fix the condenser to the foundation, and the support point is just the dead point of the LP cylinder of the steam turbine. 5
Installation
Because the condenser has a very large size, which makes integral transportation by railway impossible, as a result it is made as manifolds or components in the plant and transported to
the site for assembly. When the condenser is assembled, the drawings and installation technology provided by the manufacturer shall be followed. In order to ensure good leak proofness for the unit, during assembly the welding quality must be guaranteed and vacuum valves must be adopted in a vacuum system. When pipes of different applications are installed, necessary buffer plates must be installed. If opening piercing clashes on the reinforced accessory plates or stand bars, the original plates or bars shall be reserved as much as possible. The opening piercing for condenser shall follow the manufacturer's Condenser Piercing and Accessory Drawings When a cooling pipe is installed, it shall be confirmed that it is a qualified product. If a cooling pipe is found with severe scoring or deformation, it shall be replaced with a new one. In case that a cooling pipe is not long enough, it shall be replaced by a new one with an adequate length. It is prohibited to prolong it by heating or any other forceful means. In order to guarantee the quality and leak proofness of tube, no lubricants can be used for expanded-connecting. 6
Working process
Under normal operations, cooling water is pumped by a water circulating pump to the two front water chambers in the middle, and then, by way of the two groups of pipe bundles in the middle, flows into the back water chambers, then turns around and goes through the two groups of pipe bundles in both sides and flows back to the front water chambers in both sides, and finally flows out of the condenser. Steam enters into the condenser from the turbine exhaust outlet, then is scattered into the full length of the pipe uniformly, and then enters into the main pipe bundle zone allsidedly through the pipe bundles in the middle and in both sides, and finally is condensed through the heat exchange with cooling water pipe wall; part of the steam, by way of the channels in the middle and in both sides, enters into the hot well to reheat the condensate to reduce condenser depression. The rest steam-gaseous mixture suffers heat exchange in the air cooling zone once again, and a little steam and gaseous mixture is drawn out by vacuum pumping equipment finally. The condensate is collected in the hot well and pumped out by condensate pump, and input into the full-flow condensate system after boosting pressure.
7
Condenser testing
In order to ensure the unit's running performance, before a condenser is formally put into service, a hydraulic pressure test must be conducted for the water side, a water filling test must be conducted for the steam side, and a gas tight test must be conducted for the vacuum system. 7.1Hydraulic pressure test for the water side The hydraulic test pressure for condenser is 0.5MPa, and the water temperature shall be lower than 15℃. The test procedure is as follows: 7.1.1 Close all the valves connected with water chambers. 7.1.2 Fill clean water and load a pressure to 0.5MPa (gauge pressure at the water chamber bottom). 7.1.3 Keep the pressure for 30 minutes. During testing, it has to be noted that there shall be no leakage and seepage in the chamber flanges, manholes, and all attachment welds and the whole water chamber cannot be deformed. If any problem is found, testing shall be stopped immediately and remedial actions shall be taken. If within the time specified the check work cannot be finished completely, then the pressure hold time shall be prolonged. 7.2 Water filling test for the steam side
For the purpose of checking the installation of shell and cooling pipe, a water filling test is necessary prior to the operation of a condenser; however, it cannot be conducted with the hydraulic pressure test in the water side simultaneously. The water temperature for a water filling test shall not be lower than 15℃. When a water filling test is conducted, temporary supports shall be available for the condenser. Prior to the restart of a steam turbine just after an overhaul, a water filling test is also required. The test procedure is as follows: 7.2.1 Close all the valves connected with the shell. 7.2.2 Fill clean water (The filling height shall be 300mm higher than the joint between condenser and LP cylinder. 7.2.3 Maintain such a height for 24 hours. During testing, if any leakage or seepage in the joints between cooling pipe and end pipe sheet and in the various attachment welds of the shell or the whole external wall of the shell is deformed, the test shall be halted immediately. The clean water shall be discharged
completely. The causes shall be found and some measures shall be taken. 7.3 Gas tight test for the vacuum system In order to test the unit's installation level and learn about the tightness the whole vacuum system, a gas tight test shall be conducted. The testing method is to close the motor-driven door in the entry of the air extractor to measure the speed of breaking of vacuum. During testing, the stipulations or requirements related to gas tight test stipulated by Steam Turbine Start and Operation Illustration shall be followed. The test procedure is as follows: 7.3.1 Close the motor-driven door in the air extractor entry. Note the condenser vacuum shall drop slowly (during testing, the load shall be 80%~100% of the rated load). 7.3.2 Record the vacuum reading on time per minute. 7.3.3 Open the motor-driven door in the air extractor entry 5 minutes later. 7.3.4 Take the average from the third minute to the fifth minute as the speed of vacuum breaking. 7.3.5 Record the load of the time and the average of vacuum breaking. According to the testing results, the installation level of the whole vacuum system of the unit can be determined. If the vacuum breaking rate is less than 0.13kPa/min (1mmHg/min), then the installation is excellent; if less than 0.27kPa/min (2mmHg/min), it is good; if less than 0.4kPa/min (3mmHg/min), it is acceptable. If the vacuum breaking rate is greater than 0.67kpa/min (5mmHg/min), the unit shall be halted to find out causes and cannot be restarted before the trouble is removed. 8
Condenser running
8.1 Definition of working pressure The manufacturer defines the condenser pressure as the absolute pressure. Due to a discrepancy between the local atmospheric pressure in the plant installation site and the standard atmosphere pressure, the condenser pressure measured on site shall be converted into the absolute pressure for pressure assessment: PK=PO-PP Where: PO————Local atmospheric pressure, kPa; PP————Measured condenser vacuum degree, kPa;
PK————Condenser absolute pressure, kPa. Or
PK=0.13332(h0-hp) h0————Local atmospheric pressure, mmHg; hp————Measured condenser vacuum degree, mmHg; PK————Condenser absolute pressure, kPa.
8.2 Start Be sure to put the condenser into service prior to the start of steam turbine. First put the air extractor into service to form a vacuum to some extent within the condenser. Prior to condenser start, check all valves associated with the condenser to make them in a correct state. Meanwhile, open the air release valves on the tops of both front and back water chambers. In order to start the condensate pump, fill the condensate from the water tank to the hot well in advance (the filling level is determined according to the suction head of the condensate pump). Then recycle the condensate. When the following cases occur, stop the start: 8.2.1 Major meters such as temperature meter, vacuum gauge, and condenser water gage fail to function. 8.2.2 The automatic low vacuum safety device fails to function. 8.2.3 Condensate throttle valves and circulating water valves fail to function. 8.3 Half side operation of condenser. When cooling pipes become dirty and need half-side cleaning, or cooling pipes are damaged and need plugging operation, the condenser allows half-side operation. During half-side operation, the unit reduces its load to 75% of the rating. 8.4 Maintenance Just like steam turbine, the on-load maintenance of condenser resides in the working conditions of the supervising device as well as the safety and operating condition parameters of the condenser. The measurement items for operation monitoring are tabled as below: Instrument No.
Measurement items
Unit
Instrument installation site name
1
Atmospheric pressure
MPa (mmHg)
Panel
Atmospheric
pressure meter Differential 2
Condenser pressure
MPa (mmHg)
Condenser throat manometer Against the cooling water
3
Cooling water inlet temperature
Thermometer
℃ inlet
4
Cooling water inlet pressure
Against the cooling water
Pressure
inlet
gauge
MPa Against the cooling water
5
Cooling water outlet temperature
Thermometer
℃ outlet
6
Cooling water outlet pressure
Against the cooling water
Pressure
outlet
gauge
MPa In front or back of
7
Condensate temperature
Thermometer
℃ condensate pump
8
Condensate flow rate
t/h
In condensate pipe
Flow meter
9
TEMPERATURE OF EXTRACTED STEAM-AIR MIXTURE
℃
At air extraction pipes
Thermometer
Besides, the water level of hot well and the quality of condensate shall also be monitored. The water level of hot well is displayed by a water level indicator. During normal operation, the normal water level in the hot well shall be 0.775m higher than the inner side of the bottom plate. For the purpose of safe operation, too high or too low is not allowable. To check the condensate quality, the oxygen content, salt content, hardness, and alkalinity shall be monitored. Under normal operations, the oxygen content shall be no greater than 30ug/L. 8.4.1 In order to ensure the cleanliness of condenser titanium pipes, such cleaning measures as rubber ball rinsing, half-side rinsing, circulating water dosing, or the combinations of them shall be taken. A power plant can determine to adopt which cleaning combination based on the quality of circulating water and the operating experience. 8.5 Load-dropping operation and condenser out-of-commission Prior to the step-out of steam turbine, the load steps down, so does the steam discharged by
steam turbine. During a load-dropping operation, it has to be noted that whether the condensing water level and vacuum are normal. If not normal, some measures must be taken to bring it back to the normal water level; meanwhile, attention shall be given to whether the exhaust temperature is normal. If the idling time exceeds one week, the water in a condenser must be fully discharged and dried against corrosion. 8.6 Operation troubles and treatment Condenser running failures primarily result from the raising of condenser pressure (breaking of vacuum). The raising of condenser pressure affects not only the economical efficiency of the whole unit but also the life and reliability of the unit. If condenser pressure rising is found, the causes shall be identified and then removed. 8.6.1 Check up the exhaust temperature and condensate temperature, and check whether the load varies. 8.6.2 If there are operations at that time, they must be suspended. Restore it to the original state immediately. 8.6.3 Check whether the circulating water inlet and outlet pressures and temperature vary. 8.6.4 Check whether the air extractor works normally. 8.6.5 Check the water level of hot well and whether the condenser booster pump works normally. 8.6.6 Check other factors that have an influence on vacuum. During checking, if the condenser pressure ascends to the unit's alarm limit or halt limit specified by Steam Turbine Starting and Running Specifications, corresponding alarming and halting shall be conducted. For an emergency shutdown, the vacuum breaking valve shall be opened. For a normal shutdown, it is not allowed to open the vacuum valve.
Pressure measurement unit
Row A
Row B
Stream turbine side
Motor side
Pressure measurement support
Condenser throat Corrugated type expansion joint
LP heater LP heater
Temperature-decreased pressure reducer
Condenser shell
Front water chamber
Cooling water outlet
Back water chamber
Hot well
Water level well
Sliding support
Figure 0-1-1 Condenser figuration drawing
Fixed support
Cooling water inlet
0-2 Characteristic diagrams of condenser
Water resistance curve of condenser Calculated water temperature: 26 ℃
Water resistance loss 水阻损失
kPa
Water flow base: 41050 t/h
Water amount 水量 Figure 0-2-1 图 0-2-1
%
Condenser back pressure-water flow characteristic curve 17750 m2
Area:
Water flow base: Heat load:
41050 t/h
381217.8 kJ/s
18
16
12
10 33 30
8
6
26 20
4
15
Inlet circulating water temperature
Condenser back pressure
kPa
14
10 5
2 40
60
80
100
Figure 0-2-2 图 0-2-2
120
Water volume %
Condenser back pressure-heat load characteristic curve 17750m2
Area:
Water flow base: Heat load:
41050t/h 381217.8 kJ/s
33
11
30
℃ 26
7
20 5 15 10
3
5
Inlet circulating进口循环水温 water temperature
Condenser back pressure
凝汽器背压
kPa
9
1 0
20
40
60
80
图 0-2-3
100
120
热负荷
%
sectoion3
Specification for Pneumatic Control System of Steam
Extraction Check Valve of Steam Turbine（N300-16.7/537/537-8） 0-1 Specification of Control System of Steam Extraction Check Valve 1. Purpose and Feature The pneumatic control system of steam extraction check valve is the dynamic control center of steam extraction check valve and exhaust check valve for HP cylinder for each section of steam turbine. It introduces various set signals into the electromagnetic valve in the system according to the requirements of assembling unit to control the working states of relevant check valves so as to meet the needs of various working states of assembling unit, shown in Fig.0-1-1. The system adopts the compressed air with 0.6MPa (absolute) pressure as the dynamic source. It has the features of simple structure, easy setup of dynamic air source, free of contamination, etc. When the dynamic source of compressed air acts on the operating devices of valves in the system, it enables the steam extraction check valve and exhaust check valve for HP cylinder for each section at the free state. When the medium flows in the positive direction, the valve opens; when the medium flows in the reverse direction, the valve closes. When the controlling air source is lost, the steam extraction check valve and exhaust check valve for HP cylinder rely on the spring operating force and go to the closed state. Therefore, the system is safe and reliable. Heat load
2. Composition of System The air source part in the system adopts the mother pipe system. It consists of the air cylinder, cut off valve, air filter, pressure gauge, etc as well as the air filter, relief valve, two-position
Figure 0-2-3
three-way electromagnetic valve, manual test valve, pneumatic control valve, etc. Among them, the air cylinder, cut off valve, air filter and pressure gauge shall be prepared by the project. The air filter on the mother pipe of air source is used to filter the sundries in the compressed air to ensure the cleanness of compressed air. The cut off valves at the two ends are used to cut off the air gateway when the air filter on the mother pipe needs to be repaired or replaced. At the same time, a cut off valve is installed on the air supply branch piece of each check valve to facilitate the replacement and maintenance when the electromagnetic valve, pneumatic control valve and manual test valve are damaged. When one group of branch pieces is under repair, the entire system can still work properly. This has been taken into the consideration during the system design. It shall be noted that during the normal operation period of assembling unit, only one group of branch pieces is permitted for repairing. Repairing more than two groups of branch pieces at the same time will affect the system reliability and the safe operation of
assembling unit. The control of check valve adopts the mode of one-to-one correspondence of branch pieces. Based on the structural features of operating device of check valve and the operational requirements of assembling unit for valve performance, the check valve adopts the two-position three-way single normal power-on type of electromagnetic valve, manual test valve and pneumatic control valve as the controlling and switching components. When the power is off, the steam extraction check valve and exhaust check valve for HP cylinder are at the closed state to ensure the safety and reliability of system.
3. Working Principle
Based on the requirements of various operating states of assembling unit, relevant open and close signals are introduced into the corresponding electromagnetic valves in the system. The valves are activated so as to enable each steam extraction check valve and exhaust check valve for HP cylinder at the working states required by the operating state of assembling unit. When receiving the open signal, the electromagnetic valve on each air passage is powered on and connected to the air source. The compressed air enters into the operating device (cylinder chamber) of corresponding check valve to enable the check valve at the free state. Under the action of steam flow in the positive direction, the check valve opens. If the steam turbine rejects the load or the main steam valve closes, for each steam extraction check valve and exhaust check valve on each air passage, when receiving the close signal, the electromagnetic valve loses the power and cuts off the gateway between the air source and the operating device of check valve to enable the connection between the operating device and the air exhaust orifice of pneumatic control valve. Under the action of spring force, the operating device closes the check valve. When the internal water level of heater in the corresponding section rises to the critical water level that needs to cut off the steam extraction, the electromagnetic valve loses the power and disconnects the air source, and then the steam extraction check valve closes. The detailed operating principles of steam extraction check valve and exhaust check valve for HP cylinder can be found in the manual of valves supplied with the machine. 4. Air Source and Signal Source in the System as well as the Requirements of Installation and Maintenance. 4.1 Air source: clean compressed air with 0.6 MPa (absolute). 4.2 The air source shall dry, clean with adequate air quantity and constant pressure. 4.3 The air filter shall be periodically cleaned.
4.4 Working power for two-position three-way single electronic control electromagnetic valve: AC220V/50Hz. 4.5 Ambient temperature for the electromagnetic valve: -5～+40℃, medium temperature: -10～+60℃. 4.6 Before installation, all the lines in the system shall go through pickling and phosphorizing. The system equipment shall be cleaned. The system cleanness shall meet the requirements of J-1 in JB/T4058-1999 “Cleanness of Steam Turbine”. 4.7 The lowest point of system line shall have a drainage point. Depending on the water accumulation situation in the system, regular drainage time shall be specified. 5. System Test and Method 5.1 After repairing or before the start-up of assembling unit, the system linkage test and activation test of check valve shall be performed. 5.2 During the normal operation period of assembling unit, the activation test of steam extraction check valve shall be performed monthly to check its flexibility. 5.3 Regular activation test shall be performed one by one. Only when one group is finished and reset, the test of next group can be performed. 5.4 Procedures of Activation Test 5.4.1 Procedures of Activation Test of Check Valve
Press the test button on the manual test valve to connect the compressed air gateway that goes into the part under the piston of operating device of valve with the atmosphere. Thus, the compressed air in the chamber under the piston of operating device will leak to outside. Because the chamber above the piston of operating device is connected with the atmosphere, under the action of spring force, the piston will move downward. When the movement closes to the half of stroke, release the manual button on the test valve to enable the check valve return to the free state. The activation test is finished. 5.4.2 It shall be noted that the movement stroke shall not be excessive during the activation test, otherwise the normal operation of assembling unit will be affected. 5.4.3 The activation test for the exhaust check valve for HP cylinder shall be performed once per 2-3 months.
der
Cutoff Valve
Air Filter
Cutoff Valve
Pressure Gauge
Air Source 0.6 MPa (Absolute)
Cutoff Valve
Cutoff Valve
Free State
Free State
Cutoff Valve
Cutoff Valve
Free State
Cutoff Valve
Free State
Cutoff Valve
Free State
Cutoff Valv
Free State
ed by Each Air Passage
Purpose for No.3 HP Heater for No.2 HP Heater for No.1 HP Heater for Deaertor and Power Plant for Deaertor and Power Plant for Small Steam Turbine of Feed Pump for No.5 HP Heater for No.6 HP Heater Steam (Cold Section) Steam (Cold Section)
Remark Inlet Inlet Inlet Inlet Inlet Inlet Inlet Inlet Inlet Inlet
System Control Mode
Item Control of Steam Extraction Check Valve Movement Electromagnetic Air Valve (A-H) signal
Check Valve
Control of Exhaust Check Valve for HP Cylinder Electromagnetic Air Valve (I-J) Check Valve
set close cut off air source close cut off air source close set open connect to air source free State connect to air source free State set free connect to air source free State connect to air source free State cut off heater cut off air source in corresponding section close in corresponding section Note: 1 Refer to the start-up operation manual and the system specification for the details about the set signals. 2 “Free State” refers to the state that the check valve can be opened when the medium flows in the positive direction and closed when the medium flows in the reverse direction. 3 “Connect to Air Source” means that the compressed air enters into the inlet of operating device of check valve through the electromagnetic air valve; “Cut off Air Source” means that the electromagnetic air valve cuts off the compressed air to the operating device of check valve.
Fig. 0-1-1 Diagram of Pneumatic Control System of Steam Extraction Check Valve
1. Air source: compressed 2. During the installation conduit shall be pickled a of sundries. The cleanness “Cleanness of Steam Turb 3. Control air source inter check valve for HP cylind 4. Working voltage of elec 5. The lowest place of sys shall be performed. 6. Before the start-up of a be performed per the syst performed regularly. Refe 7. The valves and accesso together with the exhaust valve. Other valves and ac
section4
Self-sealing Turbine Steam Seal System Specifications
0-1 Self-sealing Turbine Steam Seal System Specifications 1 Overview The turbine steam seal system is primarily used to prevent steam from leaking outwards along the shaft ends of HP and IP cylinders and even flowing into the bearing box and resulting in water polluting lubricating oil; it is also used to prevent air from seeping into the steam cylinder and as a result destroying the vacuum of the unit. The self sealing turbine steam seal system refers to the system in which the steam escaped from the shaft end steam seals of HP and IP cylinders is, after spray desuperheating, used for the gland sealing steam supply for LP shaft ends during the normal operation of a unit. The surplus leaked steam flows to the LP heater or condenser through an overflow station. During the unit's start or low load phase, the gland sealing steam supply comes from the outside. From the start to the operation at full load, the turbine steam seal system can conduct automatic switching in accordance with the unit's gland sealing steam supply requirements. The system is featured by simplicity, safety, reliability, and good applicability. 2 System composition and major equipment The system consists of the steam supply and leakage pipes of gland seal, the valve-stem steam leakage pipes of stop valve and control valve, the valve-stem steam leakage pipes of IP combined steam valve, and other related devices. (for details, see Figure 0-1-2) A three-valve system is adopted for gland steam supply, that is, under all operation conditions, the steam supply pressure for a steam turbine is controlled via three control valves, namely, HP steam supply control valve, subsidiary source supply control valve, and overflow control valve, all of which ensure that the set steam pressure in the steam supply main pipe can be maintained automatically under any operation condition. The subsidiary source steam supply station has two steam supply sources. Except the reheating section of the unit itself, subsidiary steam supply from other than the unit is also available. During start or operation at low load, the subsidiary steam enters into the self-sealing system through the control valve of the subsidiary source station. The above three
control valves, their cut-off valves, and the necessary by-pass valves make up three pressure control stations. Furthermore, in order to meet the LP cylinder gland steam supply's temperature requirement, a direct-contact desuperheater is set up in the main pipe of low-pressure shaft gland steam supply. Temperature control is used to control the water spray, which as a result realizes that the desuperheating steam meets the low-pressure shaft gland's steam supply requirement. The actuators for all control valves in the system runs in an electrically way and are controlled by DCS. Import components are adopted for all the control valves and actuators, which can perform stably and reliably. In order to ensure that the main steam supply station is at a hot bank status all along the normal operation, a bypass with throttling orifice plates is set up in front of the control valve. During a normal operation, the steam goes from the gland sealing steam supply main pipe to the pressure control station through the bypass, which keep the station in a hot bank state. In the system there are also set up a JQ-110-3 gland seal heater and two shaft gland blower fan (one of them as a standby), which are used to extract the leaked steam (or air) in the final section of shaft gland chamber and to keep the chamber run at a minor negative pressure. In order to prevent foreign substances from entering into the shaft gland, a Y-type steam filter is set up at each branch pipe of steam supply. In the steam supply main pipe there is set up a safety valve with a set-pressure of 0.3MPa(a), which can prevent the occurrence the over high steam supply pressure. 3 System operation 3.1 Preparation for start 3.1.1 Shut down all pressure regulating stations, put through the steam supply source, and adjust the temperature of the steam supply line to a superheating temperature. 3.1.2 Confirm that the instruments and meters of the system are normal. 3.1.3 Confirm that the turning of steam turbine has been put into service. 3.1.4 Confirm that the recirculation of condensate has been established. 3.1.5 Open the manual and electric check valves of all the pressure control valves
and temperature control valves. 3.1.6 Put through the electric control valves and the corresponding EPSs. 3.1.7 Open the manual gate valve in the cooling water (condensate) line of the gland seal heater, which puts the gland seal heater into service. 3.1.8 Open the shaft gland blower fan, and open the electric butterfly valve in the fan's admission line. The fan is put into service normally (one for service, the other for standby). The gland seal's steam return line maintains a negative pressure, and the pressure is adjusted to about 95～ 99kPa (absolute). 3.2 Start 3.2.1 Cold start 3.2.1.1 In the cold start, the steam is supplied by the subsidiary source station. 3.2.1.2 After closing the control valves in both HP source station and overflow station, open the electric check valves in the control valve line of the subsidiary steam supply source station; confirm that the system is normal input and runs automatically in accordance with the following steps: A) Turning, rolling, and low load phase The gland sealing steam supply comes from the subsidiary source, and the pressure of the steam supply main pipe is maintained at 0.124MPa (absolute). B) 25%-load to 60%-load phase When the unit load ascends to 25% of the rated load, the cool head of reheat pipe can fulfill all the requirements of gland sealing steam supply, the steam is supplied by the cool head of reheat pipe, and the main pipe pressure is automatically maintained at 0.127MPa (absolute). C） 60%+ load phase When the load is increased to more than 60%, the quantity of steam leaked from HIP cylinder shaft ends into the supply main pipe exceeds that required by the LP cylinder gland seal. When the main pipe pressure ascends to 0.130MPa (absolute), the control valves of all steam supply stations are closed automatically; the control valves in the overflow station are opened automatically and discharge the redundant steam to the condenser through the overflow control station. Up to this point, the turbine steam seal system enters into a self sealing state and the
pressure of main pipe maintains at 0.13MPa. During a normal operation, the electric check valve in the cool head of reheat pipe shall be shut down. 3.2.2 Hot start 3.2.2.1 If there is a qualified subsidiary steam supply source, the gland sealing steam is supplied by the subsidiary source station. The parameters of the subsidiary source fail to meet the requirements, the gland sealing steam is supplied by the HP source station. 3.2.2.2 If adopting the HP steam source, confirm that after the control valves of the subsidiary source station and the overflow station are closed and the electric check valve in the control valve line of the main steam supply station is opened, the steam supply system shall be put into service normally and run automatically in accordance with the following steps: A) Turning, rolling, and low load phase The gland sealing steam supply comes from the main steam supply station, and the pressure of the steam supply main pipe is maintained at 0.118MPa (absolute). B) 25%-load to 60%-load phase When the unit load ascends to 25% of the rated load, the cool head of reheat pipe can fulfill all the requirements of gland sealing steam supply, the steam is supplied by the cool head of reheat pipe, and the main pipe pressure is automatically maintained at 0.127MPa (absolute). C) 60%+ load phase When the load is increased to more than 60%, the quantity of steam leaked from HIP cylinder shaft ends into the supply main pipe exceeds that required by the LP cylinder gland seal. By this time the main pipe pressure ascends to 0.130MPa (absolute),
the
control
valves
of
all
steam
supply
stations
are
closed
automatically, and the control valves in the overflow station are opened automatically and discharge the redundant steam to the condenser through the overflow control station. Up to this point, the turbine steam seal system enters into a self sealing state and the pressure of main pipe maintains at 0.13MPa. During a normal operation, the electric check valve in the cool head of reheat pipe shall be shut down. 3.2.3 Unit load rejection phase
When load rejection occurs, it shall be treated by the following two means: a) If there is a standby subsidiary steam supply source conforming to the temperature requirement, the pressure of the main pipe for gland sealing steam supply can be down to 0.124MPa. Close the overflow governing valve and the gland sealing steam is supplied by the subsidiary source station. b) If the unit has no standby subsidiary steam sources or the parameters of the subsidiary sources fail to meet the requirements, the subsidiary sources and cool head of reheat pipe cannot be used. The electric check valve in front of the control valve of the subsidiary source station must be closed. The pressure of the main pipe for gland sealing steam supply is down to 0.118MPa. The overflow governing valve has already been closed automatically, and the HP steam supply control valve is opened automatically. The steam is supplied by the main steam supply station, namely, the HP steam source adjustment station. 3.2.4 Putting into service of temperature adjustment station Under all operation conditions, a temperature adjustment station can maintain the temperature of the LP gland seal chamber at 121～ 177 ℃ . 3.2.5 Putting into service of by-pass valve When the throttle pressure of a subsidiary steam supply control valve is 25% lower than the rating, or when the steam turbine starts with a wearing gland seal, in order to get adequate steam flow to seal the steam turbine, the by-pass valve of the subsidiary steam station will be open for steam supplement. When the throttle pressure is high enough to maintain the steam for gland seal, the by-pass valve will be closed. If the by-pass valve is still open, the surplus steam will be automatically discharged into LP heater or condenser by way of the overflow valve. Such a case does not made any difference to the turbine operation, but it will lower the efficiency of the power plant slightly. 3.2.6 Steam temperature requirements 3.2.6.1 Subsidiary steam parameters' requirements No.
Application
Steam （ MPa）
pressure Temperature (℃)
Used for
Steam source
1
Warming
About
Cold start
150~260 2
Steam
0.588~0.784MPa
About
turbine gland
208~375
sealing
About
Subsidiary steam
Hot start
header
Cold start
150~260 3.2.6.2 Steam turbine gland sealing's temperature requirements In order to avoid the inconsistency between the temperature of seal steam and that of turbine rotor, the steam supply temperature must meet the required needs. In general, in the main pipe of gland seal with a absolute pressure of 0.127MPa, it is allowed that the temperature of seal steam is 167 ℃ higher or 167 ℃ lower than that of the metal. Excessive temperature differences between seal steam and rotor will result in a high heat stress on the rotor surface in the gland seal zone. Each heat stress cycle will result in the alternate life loss of part of the metal, while the recurrence of excessive temperature difference of rotor will give rise to heat fatigue cracking on rotor surface; meanwhile, the excessive temperature difference will also bring about excessive expansion difference between the rotor and the stator. 3.2.6.3 Specific steam temperature requirements In a cold state (when the first shell temperature of steam turbine is lower than 150 ℃ ); When the maximum steam temperature under the main pipe pressure is 260 ℃ and when the minimum steam temperature under the main pipe pressure is 150 ℃ . In a hot state (when the first shell temperature of steam turbine is higher than 150 ℃ ); When the maximum steam temperature under the pressure in the main pipe for gland sealing is 375 ℃ and when the minimum steam temperature under the pressure in the main pipe for gland sealing is 208 ℃ (the maximum temperature of gland-packing leakage minus 167 ℃ ). The above parameter requirements are shown in Figure 0-1-1. 3.3 Emergency adjustment 3.3.1 In order to prevent the occurrence of steam supply overpressure accident,
there are set up a full-open-type safety valve with radiator spring with a set pressure of 0.3MPa in the main pipe for steam supply. In order to guarantee a safe operation, there shall be set up sound and light alarm devices for overpressure alarming with an alarm pressure of 0.25MPa in the main pipe for gland sealing steam supply, so that the system operation can be monitored at any time. 3.3.2 Gland sealing back-steam pressure adjustment If end steam leakage is found during operation, the throttle of gland sealing blower fan can be adjusted to guarantee a certain negative pressure is maintained in the gland sealing back-steam chamber, at about 95~99kPa (absolute). 3.3.3 When there are failures in the steam supply stations and overflow stations, control valve hand wheels and by-pass valves can be used to adjust the system. 3.3.4 Under an abnormal working condition, if the bypass channel of the steam supply control valve is opened or the control valve of the steam supply station is open, excessive steam will enter into the main pipe for steam supply by way of the steam supply station. No matter which case occurs, the overflow control valve will be automatically opened. If the overflow control valve also goes wrong, the motor operated gate valve in the bypass of overflow station can also be opened. 3.4 System shutdown 3.4.1 Confirm that the steam turbine is in the shutdown and turning phase. 3.4.2 Cut off the electric check valves of all steam supply pipes. 3.4.3 Cut off the motorized valve in the water inlet of the desuperheating station. 3.4.4 Cut off the power supply of the gland sealing control valve. 3.4.5 Confirm that all the drainage points are free from obstruction. 4 Precautions for installation and operation 4.1 In order to ensure that the system can run safely, the components such as control valve bodies and actuators have been calibrated and aligned in the manufacturer's plant, disassembly of them is not required during installation. 4.2 A drain pipe shall be set up the low level point after the valve of a steam supply control station, and water in the drain pipe flows into the condenser by way of a throttling device. 4.3 A drainage point shall also be set up after the direct-contact desuperheater, with its position at least 2.5m after water spraying, and the drained water flows
into the condenser by way of a throttling device. 4.4 The minimum distance from the spraying part of the direct-contact desuperheater from the LP gland seal shall be 15~17m. After water spraying, a straight section at least 5m longer shall be available, and its diameter shall be the same as that of the direct-contact desuperheater shell. 4.5 In a turbine steam seal system the pipes before the steam supply control station shall have continuous incline towards the steam source (main steam, subsidiary steam, and the steam in the cool head of reheat pipe) direction with a gradient of slope of 1/50. If these pipes are connected to the source in a inclined way, a drain pipe must be set up at the inlet side of each valve to prevent the water from being accumulated. The drain pipe must be a continuous one with throttling orifices. 4.6 All the pipes for gland sealing steam supply shall be inclined continuously downwards to the gland sealing pressure control station direction with a slope of 1/50. If there is a low level point in the piping system, a continuous drain pipe with throttling orifices shall be used to drain the water to the condenser. 4.7 All the pipes of steam-air mixture from gland seal and valve stem leakage shall be inclined towards the direction of the gland seal heater, with a slope of 1/50. If there is a low level point in the piping system, a drainage point shall be set up, and the drained water shall be discharged into the condenser. 4.8 The condensate from the gland seal heater is discharged into the condenser through a water-sealed pipe. 4.9 Before the vertical climbing of the exhaust duct of a shaft gland blower fan, a downward slope starting from the fan and ending in a low level drainage point shall be available for the duct. During operation, it shall be guaranteed that the drainage is clear. Two fans (one for standby) shall be connected in parallel. 4.10 The steam filter in a steam supply line shall be fitted on a horizontal position. 4.11 The pressure control signals for all electric control valves come from the main pipes for steam supply, and the temperature control signals from the gland seal chambers. Due to such reasons as arrangement, the temperature measuring
point after a direct-contact desuperheater shall be set up on the main pipe, and the distance from the measuring point to the desuperheating spraying part shall be no less than 15m. It shall approach the gland seal chamber as near as possible. 4.12 The steam pipelines to the same place can be combined, but the pipe diameter shall be big enough. 4.13 Purging is required for all pipes. The cleaning for all pipes and equipment in the system shall be performed in accordance with clauses 3 and 2 in JB/T4058-1999 Steam Turbine Cleanliness. 4.14 The inlet of the shaft gland blower fan for standby must be closed. 4.15 The steam filters shall be washed regularly. 4.16 When the pipe medium temperature is lower than 400 ℃ , No.20 steel pipes shall be adopted; when it is higher than 400 ℃ , alloy -steel pipes shall be adopted. 5 The calibration and operating conditions of the control valves in all control stations are as follows (see Table 0-1-1). Table Pressu re of gland sealing main pip e MPa
HP
steam
co ntrol
co ntrol
station
station
Close
0.127
Close
0.130
Close
0 .118
Subsidiary
source
0.124
0 .118
steam
Op en
Op en
adjust
source
Op en adjust Close and
and
Overflow co ntrol
Running statu s
station and
adjust
adjust Op en
0-1-1
and
Vacuu m
Close
(cold start) ～ 25% load
Close Op en adjust
Close
Close
Close
Close
ph ase
and
Self sealing
Load rejection Vacuu m (hot start)
ph ase
Note: The valve set pressures in Table 0-1-1 are only for onsite adjustment reference. Power plants can adjust the pressure setting value based on actual operating conditions. If no smoking occurs in all HP, IP and LP gland seals and the vacuum is not unaffected by the adjustment, it is appropriate. 6 Simple manipulation measures for common troubles (see Table 0-1-2) Table 0-1-2 Failure Too
high
pressure in main pipes fo r
gland
steam
Failure source
Simple manipulation measures
1 The steam su pply con trol
1 Check the control signals of the control
valve is not tightly closed.
valve and its tightn ess. If h aving co n firmed
2 External steam goes into
th at it is not tight, info rm the man u factu rer
th e system.
o r the suppo rt plants.
3
Th ere
leakage
supply
are
points
unclear near
the
2 Identify the ex ternal sou rce and cu t o ff it. 3 Find out the leakage points near the gland
gland seal.
seal.
1 The outlet valve of the
1 Op en th e ou tlet valve o f g land seal blo wer
gland seal blower fan is
fan.
closed.
2 Adjust the cooling water volume in the
2 The v olu me o f cooling
gland seal heater to make the pressure in the
water in the gland seal
heater no greater than 95k Pa(a).
S mo ki ng in
heater is too small.
3 Let the steam-air mixture retu rn line be
th e
3 The steam-air mixture
in clined continuou sly to ward s the gland seal
return line is not rationally
heater d irection with a slope of 1/50,
arranged.
do not let the mixture enter into the inlet
4 The drainage for the low
pipe section of gland sealing heater from
level point of
lo wer p art.
gland
seal
steam-air
mixture is not clear.
and
4 Keep clear the passage for drainage in low level point
High
1
temp eratur
fou ling
2 Clean the water filter.
e
2 Water filter fouling
3 Ch eck the po wer sou rce and co ntrol sig nals
pressure
3
control
of the control valve.
steam
valve fails control
1.1 Check the power source and control
for
low
Desuperheater
The
spraying
nozzle
1 Clean the nozzle.
supply Low
1
The
spraying
temp eratur e
for
valve is no t tigh tly closed .
LP
sign als o f the co ntrol valve. 1 .2 Ch eck wh ether the con trol v alve has
steam
in tern al leakage. If it has, p lease co ntact the
supply
man u facturer o r support plants for treatment measures.
Because whether the turbine steam seal system can run normally is related to not only the equipment configuration but also the on-site arrangement, when the system is abnormal, if the above simple manipulation measures do not take effect, please contact DFSTW. 7 If the contents of the specification are not in agreement with the Unit Start and Run Specifications, the latter will prevail.
Gland steam temperature
汽封蒸汽温度(℃)
400
375℃ Allowable temperature for hot 汽轮机热态启动 start of steam turbine 时的允许温度
300 260℃ Gland steam
汽封蒸汽的温度要求
200
208℃
temperature requirements
Allowable 汽轮机冷态启动 temperature 时的允许温度 cold start of turbine
for steam
150℃ 100 0
30% 50% 70% 100% Load 负荷（%）
Figure 0-1-1
Allowed band of gland steam temperature
IP Main Steam Governing Valve
ve Lever Leakage (Valve Cap)
Condenser throat
To Deaerator
IP Main Steam Valve Lever Leakage (Valve Cap)
IP Main Steam Governing Valve Lever Leakage
HP Main Steam Valve
ain Steam Governing e Lever Leakage
Shaft seal fan
ed-water Pump Turbine Steam Seal Steam Supply
Steam Se
Overflow to Stage 8
To LP Heater
From condensate pum
Feed-water Pump Turbine Stem Seal
Steam Extraction Heater
Overflow to Condenser
Main Steam Supply
Fro
Legend Shaft seal
Steam Air-Smog Condensate Control loop pipeline Mixture Pipeline Pipeline
Exhaustion to Reducer Safety valve Check Valve Electric butterfly valveAir
Figure 0-1-2
Electric Temp check valve eratur e meas Steam filter Dead end
Self-sealing Turbine Steam Seal System
Hand valve
steamElectri stop Main contro pressure transmitter
overflow Subsidiary steam pressure pressure transmitter transmitter
Tempe transm
section5
Maintenance of condensate pump
1、Operation、Starting／Shut down 1．1、Preparation before starting and operation (1)Check the water level of warm well．Its lowest level should not be smaller than the lowest value specified in<>． (2)Check if the installed instruments are working well． (3)Fill NO．20 turbine lubricating oil in the thrust beating trunk to the position of oil mark． (4)Separate the elastic coupling，check if the rotating direction of the motor is right or not (CW viewed from the motor side)，then fix the elastic pin of the coupling． (5)Fill the water for the pump，check carefully the temporary and fixed filters in the suction piping system smooth or not．Please pay attention to clean off in time． (6)Open the valve of outside supplied sealed cooling water．Check if the pipeline of sealed cooling water is smooth，then adjust the pressure of outside supplied water through adjusting valve and keep the pressure between 0．25—0．4Mpa and water capacity between 0．6—1．0 m3／h；Open the valve of bearing cooling water，check if the pipeline of bearing water is smooth．Capacity of beating cooling water is between 0．8 一 1．2 m3／h and pressure between 0．25 一 0．4Mpa．、 。 (7)Turn gear by hand．The rotating circles of the pump rotor shouldn’t be 1ess than 3 circles and check if there is something abnormal in rotating． (8)Close the discharge pipe gate valve of the pump and the screw plug of the pressure meter． 1．2．、Starting (1)Starting the motor to the rated speed，open the screw plug of the pressure meter and adjust the seal water and cooling water· (2)、open the discharge pipe gate valve gradually to the required operation conditions and check the readings of the different meters and the leakage of the seal water．Under the operation conditions of closed the gate valve，the rotatmg time shouldn’t be exceeded to 2 minutes． 1．3、Operation (1)Check if the non—return valve at the discharge pipes of is open. (2)Venfy if the discharge pressure meets the requirement· (3) Check if system operates smooth and vibration meets the requirement· (4) Observe control instruments of motor and thrust bearing of pump· Double metal thermometer for pump thrust bearing controls the temDeramre as follows：Alarming at 70℃，Stop at 80℃；Thermocouple tor stator winding of motor controls temperature as follows：Alarming at l30℃，StoD at 140℃；ThemlOcOuple for above and below bearing Ot motor controls temDerature as follows：Alarming at 70℃，Stop at 80℃ Attention： (1)Installation position of pump depends on that pump alwavs has water level．So during the running of pump，under any loadmg worng condition of motor unit，the
actual water level of condensate warm weII should be ensured not lower than the lowest level· (2)Pump can’t run under the minimum capacity!After start up pass this area quickly t0 avoid vibration、noise and possible net positive suction- “ (3)Stand-by unit should be put into running periodically·We recommend that 2 sets of condensate pumps with the same motor should be alternately used every 30--40 days and keep stand-by pump alwaYs m a normaI condition． 1．4、Shut down． （l） Shut down the motor and observe if pump rotors stop smoothly。 (2)Water level of warm well is at the lowest level· （3）C10se the gate valve on the discharge pipeline and cock for manometer and keep pump system in the condition of“To Be Started”· 1．5、Maintenance or delay the time of shut down 。 (1)Shut down the valve of suction． (2)Shut down the min．flow valve· (3)Shut down system of cooling water． (4)Open a11 of vents and discharge the water in the pump。 (5)Motor should be protected against the tide． 2、Maintenance of the Pump 2．1、Mechanical sealing parts. a ． Mechanical seal Axial interface of rotating and stationary rmg with high—Drecision—rubbing and the action of spring in sealing parts ensureS the thorough axial seal．Throttling function of little clearance between friction—surface reduces leakage of fluid to the least degree and ensure s_the transDortation efficiency of pump．Lubrication and cooling of friction-surface： It is done by clean water resource(condensation water or salt-removinLg water) flowing through position F in Fig7：Pressure of suction nozzle： 0．4-0．6Mpa； Water Capacity：0．8 一 1．2 m3／h；Temperature lower than 38。C．Discharge nozzle F，should ensure that its pressure is between O．1—0．2Mpa．If resource pressure is lower man 0．3Mpa or water capacity smaller than 0．5 m3／h，inspection should be done immediately．If it cannot go back to nor．mal value within．12 hours, machine should be stopped to repair． b．stuffing seal before starting，The external sealing water system must be startup，the pressure p=O．25-0．40Mpa，capacity Q===5～l0 l／h．The leakage of sealing water is discharged by two holds in different place on the stuffing gland．The material of packing is PTFE，the wearable capability of which is better than others．Adjust the tighmess of gland according to the leakage．When supply system of sealing water is normal，just adjust the nuts on the gland． When replace the stuffing，just take the gland down and replace the stuffing． 2．2、Thrust bearing parts Use No．20 turbine lubricating oil for upper guiding bearing and thrust bearing，before filling the oil，the oil tank should be cleaned thoroughly．The oil level should be kept to the marked location of the oil gauge．The temperature of the lubrication oil in the oil tank
shouldn’t be higher than the environmental temperature of 25℃，the alarm temperature is 70 ℃and the shut—down temperature is 80℃．Change the lubrication oil，after 300 hours of the first operation，afterwards check me oil level periodically．It shouldn’t be lowest than the low level marked on the oil gauge．The cooling water of the inner oil cooler is industry pure water，with temperature t≤3 8．5℃，pressure P=0．25~0.．4MPa，一 capacity Q=0．8～ 1．2m3／h．It can be adjusted according to the environment temperature． 2．3、Guide bearing and journal bearing These are the water—lubricated bearings．They are sensible to the impurities and particles．When the condensate pump(condensate booster pump)is involved in the pipe flushing of the system，the strainer must be installed on the upstream of the pump suction．When the flushing is finished，the temporary strainer on the suction side should be disassembled to ensure the effective NPSHa．If the fixed strainer is installed，the screen hole with 40 meshes is 0K． 3.Common faults and solution of condensate pump:
Symptom
Cause Solution 1. There is something wrong with motor or electric system. 1. To check motor and electric system It can’t 2. Foreign matter enters rotary 2. To clean away the foreign matter be started part, resulting in block. 3. To repair the bearing 3. Bearing exists fault and is blocks or too tight. 1. Air leaks from negative pressure
It is under capacity or it doesn’t discharge water
It is under overload
1. To find out and eliminate the leaking position 2. Impeller is spoilt. 2. To replace impeller. 3. Outlet valve is regulated 3. To regulate outlet valve again or overhaul improperly or outlet/inlet valve of fault. core falls off. 4. To increase the water level of condenser. 4. Water level of condenser is too 5. To rearrange connection of motor and low correct its direction. 5. Rotary direction is reverse 1. Bearing is spoilt. 1. To overhaul of bearing. 2. Friction exists between 2. To overhaul and regulate rotary part. impeller and shell. 3. To turn down recirculating valve or start 3. Flow is too large standby pump. 4. Packing gland is too tight. 4. To loosen the packing gland. 5.Motor is in lacking phase 5. To check connection of motor and switch. operation. part.
1.Coupler is of disalignment. 2.Bearing is spoilt. 3.Shaft is bent, and rotor is
1. To make alignment again.
Pump or unbalanced. motor 4.Bolts of coupler are not in good exists connection abnormal 5.Foundation bolts are loose or vibration foundation is weak. 6.Rotor part is loose. 7.Motor is out of service.
Section6
2. To replace bearing. 3. To straighten shaft and eliminate imbalance 4. To refasten or replace the bolts. 5. To fasten the bolts or reinforce foundation. 6. To overhaul loose part. 7. To repair motor.
Feedwater Pump
1 Function and 0perating Characteristic of Feedwater Pump Feedwater pump is the most important water pump, it continuously provides boiler with feed water possessing enough pressure & flow & temperature. Safe and reliable operation of feedwater pump is directly related to safe operation of boiler devices. With the increase of unit capacity of power plant, auxiliaries equipped are relatively developed and position of feedwater pump providing boiler with feed water. Feedwater pump of modern large-scaled boiler is large in capacity and high in rotary speed, and this kind of boiler puts forward new request on drive pattern & structure & material of pump. At present all the unit plants participate in power network cycling, resulting in increase of variable range of flow in water pump and change of head & suction pressure & feedwater temperature along with that, accordingly new problem occurs in operation of feedwater pump. With the restrict of network frequency, the highest speed of motor can’t exceed 3000r/min, this will result in much increase of not only series but also length and weight of feedwater pump, severely affecting reliability and economy of feedwater pump. Shell of previous high-pressure feedwater pump was generally of multistage sectional type, but that of present is of double-shelled cylinder type, which makes slight difference of temperature and pressure between each section of shell, heat stream and stress around axes of water pump are uniformly symmetric, in addition inter-stage leakage can be reduced owing to better sealing and safety and economy of operation are enhanced. Modern high-pressure feedwater pump is high in pressure and flowing speed, this high flowing speed possesses great scour for impeller & blade & guide blade, so utilized material should be of scour resistance & erosion resistance & small heat-expansion coefficient & good mechanic property & easy patch weld. On the operation pattern, previous feedwater pump generally ensured continuous operation of main engine via parallel operation of standby pump and multiple pumps and adapted change of load via the number of start-stop pumps and regulating opening of feedwater regulating valve. Obviously it can’t adapt the development of unit plant, modern large capacity unit plant adopts variable speed feedwater pump. It can change rotary speed and regulate load in a large range and meet requests of sliding parameter operation and network cycling of unit plant, and economy of unit operation is increased. 2 Necessity of HydraulicVariable Speed Feedwater Pump
With increase of unit capacity of turbine, pressure of feed water is needed higher and higher. Especially for go-through boiler, steam-water flowing resistance of boiler proper has to be overcome with pressure of feedwater pump. Hence, motive power driving high-speed pump should be quite large. If motor is adopted to drive high-speed pump, its highest rotary speed can only reach3000r/min due to limit of network frequency, so speed should be raised via raising speed gear at first. For the sake of economic operation, the best measure is to adopt variable speed regulation to suit change of condition. It is an ideal way to directly adopt hydraulic variable speed pump, namely to adopt hydraulic coupler, changing rotary speed to suit starting condition. More advantages to adopt hydraulic coupler are as follows: (1) Hydraulic coupler transmits power with oil pressure. It is of stepless speed change, convenient in regulation, fine in stability, small in noise and long in service life because oil pressure is not limited by grades. (2) Starting moment is large while motor-operated feedwater pump starts up from motionless to speed rating, in order to suit this moment, schemed capacity of electric machinery is often 30%～50% more than power rating of water pump, so it is of diseconomy. After using hydraulic coupler, feedwater pump can be started under lower rotary speed (or large ratio of rotary differential. In this way, schemed capacity of motor can be need not too abundant because of low rotary speed and smaller starting moment. (3) If regulating speed via oil in and out combination (it will be introduced in the next section), speed up and down will be rapid and meet special requirement of rapidly starting of go-through boiler of unit plant. (4) It can be regulated in a large range. 3 Hydraulic Coupler I. Operating principle of hydraulic coupler Hydraulic coupler mostly consists of pump wheel, turbine and rotary inner bushing (Fig.3-13). They form two chambers: circular flowing circle is formed by working oil in chamber between pump wheel and turbine; Fig.3-13 Schematic drawing of hydraulic oil ring is formed by working oil discharged coupler from the clearance between pump wheel and 1-main shaft;2-pump wheel;3-turbine; 4-spoon-type turbine (or orifices on the shell of turbine) tube;5-rotary inner bushing; 6-reflux passage;7-driven under the function of centrifugal force in shaft;8-inlet of controlling oil chamber of pump wheel and circular inner bushing. Working oil gets energy in pump wheel and releases it in the turbine; transmission power can be changed with quantity of working oil, resulting in speed change of turbine so as to suit the need of load. Change of working oil quantity can be performed with regulating valve of operating oil pump (or auxiliary oil pump) or entrance of turbine (or hollow shaft of turbine), or via changing travel (radial) of spoon type tube in the rotary inner bushing chamber, resulting in change of release of oil ring. Rotary shaft of pump wheel is a kind of drive shaft that drives via speed up of accelerating gear of motor, so drive shaft is a high-speed shaft with stationary rotary speed.
The shaft of turbine is a driven shaft, working oil from pump wheel impulses turbine to rotate with a certain pressure, driving rotor of water pump jointed on the driven shaft. In addition, speed can be changed via hydraulic coupler firstly and is raised then via accelerating gear, driving rotor of feedwater pump There are radial blades in the chamber formed by pump wheel and turbine, the number of blades is generally 20～40 pieces, the number of turbine is commonly l～4 less than that of pump wheel in order to avoid resonance, circular flowing passage is formed between blades. Working oil is thrown along radial passage and its pressure is raised under the function of centrifugal force in pump wheel, its radial relative speed is combined with circumferential speed at outlet of pump wheel, crushing inlet radial passage of turbine, and working oil impulses turbine to rotate via changing momentum moment along radial passage, its radial relative speed is combined with circumferential speed at outlet of turbine, crushing inlet radial passage of pump wheel, then energy can be attained in pump wheel. So, natural reflux is formed between pump wheel and turbine and power is transmitted. But continuous reflux of working oil can result in friction and heat, working oil should be cooled in order to avoid oil boiloff and temperature up to impeller and affect the safe operation of coupler: one is to suck out oil cooled in heat exchanger with spoon type tube, the other one is to utilize nozzle, while outlet pressure of pump wheel changes, pressure Fig.3-14 Combination regulation with differential ejected by nozzle will change and spoon-type tube and oil inlet valve oil quantity ejected by nozzle is changed, then oil is cooled in heat exchanger. While hydraulic coupler is operating, working liquid in pump wheel will produce centrifugal press with the function of centrifugal force caused by rotary pump wheel, and it is the same while turbine rotates, the centrifugal force will prevent working liquid from pump wheel from entering turbine, only when centrifugal force in pump wheel is more than that in turbine, working liquid can go from chamber of pump wheel to turbine, liquid in working chamber of hydraulic coupler can form reflux and torque can be transmitted, hence, rotary speed of pump wheel must be more than that of turbine while hydraulic coupler is operating, this is necessary condition under which hydraulic coupler can transmit torque. II. Regulation manner of hydraulic coupler
Under the condition of stationary rotary speed of pump wheel, the more working oil is, the larger kinetic torque transmitted is, and the higher rotary speed of turbine is; and rotary speed of turbine can be regulated via changing working oil quantity to suit the requirement of feedwater pump. There are basically two manners to regulate working oil quantity: ① to regulate entering quantity of working oil; ② to regulate discharge quantity of working oil. The former can be performed with additional working oil pump and regulating valve while working oil, which is ejected by nozzle on the rotary inner bushing, is cooled in heat exchanger. The more circular oil is, the higher-pressure rise in pump wheel is, and the more oil quantity ejected by nozzle, and oil temperature up is suppressed caused by increase of circular oil. Thus, ejected oil isn’t utilized and this means loss of energy, so oil ejecting orifice is shrunk as small as possible (generally calculated according to 0.5% power rating), ensuring that temperature up of working oil is not more than 30℃, under the maximum speed differential ratio (commonly ＃22 turbine oil exists no problem while it operates under 65～70℃ or even up to 95℃). The most disadvantage is: while ejected oil quantity is too small, it restricts the request for rapid speed down of feedwater pump under the condition of failure load shedding in unit plant. The latter is performed via changing radial displacement of spoon-type tube in rotary inner bushing. Because oil ring increases in inner bushing (next to inner bushing) along with radius (so centrifugal force increases), oil pressure will be increased, so change of radial displacement will result in change of speed head of oil inlet spoon-type tube. Therefore, the higher spoon-type tube is raised (the larger radial radius is), the more oil quantity is ejected, and the oil goes into heat exchanger depending on kinetic pressure of thrown oil and is cooled there. Under the condition of failure load shedding and request of rapid speed down of turbine, speed can be reduced via swiftly discharging working oil to oil storing box if only radial displacement of spoon-type tube is increased. This is the most disadvantage of regulation manner in which discharge oil quantity of working oil is regulated. Thus, it can’t response rapid speed up of turbine while load of unit plant is swiftly increased, so oil inlet pump is arranged. Therefore, modern coupler adopts combination of above two manners in order to raise rapidly speed, shown as Fig. 3-14. In the figure, load signal of boiler feedwater quantity controls servo motor which changes rotary angle of transfer bar via rotary cam because displacement of spoon-type tube isn’t of linear relationship with discharge oil quantity, thereby, the radial displacement of spoon-type tube is changed to control discharged oil quantity. At the same time, the other end of transfer bar changes opening of oil inlet valve (regulating valve) via cam on the bar, controlling oil-in quantity to coupler. While boiler feedwater quantity is needed increasing, servo motor rotates cam to ‘+’ and drives transfer bar to rotate counterclockwise, dropping spoon-type tube and reducing oil discharge quantity; simultaneously because of counter rotation of transfer bar, cam on the bar opens oil inlet valve larger and oil-in quantity to coupler will be increased, accordingly working oil quantity will be increased in coupler and rotary speed of turbine will be raised, meeting the request for increasing boiler feed water; while boiler feed water is needed reducing, servo motor rotates cam to ‘一’, increasing oil discharge quantity and reducing oil-in quantity, so working oil quantity will be reduced in coupler and speed of turbine will be reduced, fitting the request for decreasing boiler feed water. The oil discharged by spoon-type tube enters oil inlet valve
and then reverts to oil box under coupler foundation through oil return line after it is cooled in heat exchanger. While boiler feed water quantity is increased, on one hand, opening of oil inlet valve is increased, on the other hand, resistance of oil discharge of spoon-type tube is increased with the function of small spring at the bottom of oil inlet valve, so oil discharge quantity is reduced, namely, oil inlet valve simultaneously acts as controlling oil discharge and enter quantity, so working oil quantity of coupler can be regulated swiftly. 4 Operation and Maintenance of Hydraulic Variable Speed Feedwater Pump Feedwater pump providing boiler feed water possesses the outstanding position in power plant, its start, stop and operation conditions are directly related to safe & economic operation of boiler, it should be paid enough attention. I. Start and stop of feedwater pump Most feedwater pump has to be warmed up before starting. If warmth is not enough, the upper and lower shell will exist temperature differential resulting in hogback and distortion due to unequal heat expansion. It is known through testing a variable speed feed pump that coupler of main pump sinks 0.4～0.6mm while temperature differential reaches 50～60℃. If water pump is started under this condition, friction will be produced between kinetic and stationary parts to spoil devices. Important condition for warming pump enough is to adopt correct warming pattern, to ensure necessary time and to control metal temperature up & differential with reason. Warming pump splits into two patterns: normal warming and reverse warming. Water used for warming pump comes from deaerator, enters pump via suction tube and drains in front of outlet check valve, and this is called normal warming. Water used for warming pump from outlet check valve enters pump through high-pressure connecting tube (with throttle plate), and then discharges by warm-pump drain valve at inlet of pump, this pattern is called reverse warming; they can be adopted in line with operation pattern and practical condition of system. Note: Mustn’t turn the pump in the course of temperature up, preventing the rotor from seizing. Warm-pump valve is closed after normal warming is over and opened while having other conditions. While reverse, warm-pump drain valve and water valve of high-pressure connecting tube should be closed after starting. Before starting feedwater pump, every system should be checked, including oil system, cooling water system, sealing water system and feed water system, each valve should be in ON or OFF position prescribed by rules. Water should prevent from leakage and air should be exhausted via exhaust valve in system in the course of filling feedwater pump with water and loading systems. Oil system of feedwater pump should be put into operation before starting, oil pressure and temperature should comply with prescribe of manufacturer, oil system should have no leakage and each pad returns oil normally. After above operation, protection of feedwater pump should be put into operation and combination switch of feedwater and oil pump should be closed. While starting feedwater pump, operation switch is to be on. Note the return time of starting time and check vibration of bearing pad, oil temperature, axial displacement, sealing of shaft end and outlet pressure. If normal, stop auxiliary oil pump and open outlet valve. For variable speed feedwater pump, position of spoon-type tube should be at that of low rotary
speed before starting and at outlet valve after starting, and it should be regulated gradually and speed is raised according to outlet pressure. While flow reaches the permissible minimum value, recirculating valve should automatically close in order to prevent high-pressure water from scouring valves, throttle installation and tubes. After feedwater pump is put into service, outlet & inlet wind temperature and return oil temperature of each bearing pad should be noticed and regulated according to prescribed range by rules. High-pressure feedwater pump mustn’t be operated at the minimum flow under requirement, even if very short time from starting to fixed speed. If flow is insufficient, water in pump will be heated and boiled off, resulting in vibration caused by friction of pump and possible damage to devices. So before feedwater pump is started and stopped, reliability of action of recirculating valve must be ensured. Manual valves before and after recirculating valve should be in ON position. While feedwater pump is needed stopping, auxiliary lubricating oil pump should be started and spoon-type tube is regulated to reduce flow, outlet valve should be closed while flow is reduced to zero. Pump can be stopped after outlet valve is entirely shut down. If outlet valve isn’t entirely closed while stopping pump, water pump will reverse once check valve is seized. After stopping feedwater pump, inlet valve of oil cooler and air cooler of motor should be shut down. If feedwater pump acts as standby, auxiliary oil pump should be kept operating and dampproof heater of motor should be put into operation. Auxiliary oil pump can be stopped after working for a period of time (generally about 10min) when it is needed repairing. II. Operation and maintenance of feedwater pump During operation of feedwater pump, inlet pressure, inlet water temperature, current of motor, pressure of balance chamber, pressure of lubricating oil, oil level of oil box, temperature of bearing, leakage condition of mechanic sealing or padding sealing, wind temperature and vibration of motor and so on should be checked mainly. Normal pressure of balance chamber should be 0.05～0.2MPa more than that of inlet. If pressure of balance chamber rises and exceeds 0.95Mpa, the cause should be found out. Pressure of lubricating oil should be kept at 0.1 ～ 0.24Mpa, and pressure value can be regulated through pressure-relief valve. The cause should be found out if pressure of oil is reduced, except for leakage of oil system or abnormal operating of oil pump, it is usual that oil screen is blocked. Outlet oil temperature of lubricating oil cooler should be 35～46℃. Metal temperature of bearing should not be more than 65℃, if it reaches 70℃, alarm single should be given, if up to 75℃, pump should be shut down emergently. After new water pump operates 200h for the first time, lubricating oil should be discharged completely and be replaced with new oil, then replacing oil every 1000h. While replacing oil, the whole lubrication zone (including bearing) should be cleaned out with gasoline or benzene. Oil should be supplied in time according to oil level condition of oil box. While turbine sheds load emergently and is shut down, pressure of deaerator should be kept. If pressure is dropped too swiftly and water temperature is dropped relatively, each
section of feedwater pump is rapidly shrunk, resulting in leakage of joint section. So inlet water temperature drop of pump should not be more than 1℃/min. Feedwater pump should be avoid frequent start and stop, especially when feedwater pump adopts balance disc to balance axial trust, balance disc may touch and attrit while pump starts. Rotor will swing to inlet if axial trust can’t be balanced when pump is from start to stationary speed; namely, outlet pressure is from zero to stationary pressure. Permissible times of continuous start of feedwater pump should be executed according to operation rules of motor. If continuous starting times are overmany or time interval is short, motor will be ruined. Motor and its auxiliaries should be checked and motor insulation should be measured if it trips, and it can be started again if everything is ok. If the second start is unsuccessful, the cause should be found out and be eliminated, the third start should be done after 1h. Rotary speed of variable-speed feed pump can be regulated, it consists of booster pump, motor, hydraulic coupler and main pump. Booster pump is directly driven by one end of motor shaft while the main pump is driven via hydraulic coupler driven with acceleration gear by the other end of motor shaft. Drive wheel (pump wheel) and driven wheel (turbine) composes a chamber, namely operating chamber of hydraulic coupler. Operating chamber is full of working liquid, generally turbine oil. Rotary speed of main pump varies with working oil quantity in hydraulic coupler. Oil quantity is regulated with spoon-type tube. Change of position of spoon-type tube can result in rotary speed of main pump. Oil traveling to hydraulic coupler is called operating oil while oil traveling to variable speed box and bearings of pumps is called lubricating oil. Compared with feedwater pump with stationary speed, feedwater pump with variable speed possesses the following properties on operation: (1) Feedwater flow and pressure are regulated with change of rotary speed, not with throttle of valves. (2) Regulating test should be done with spoon-type tube before starting pump, spoon-type tube is regulated manually to check its flexibility firstly and operated in the main control room, indication of spoon-type tube position on meter panel should confirm to local position. (3) Booster pump and main pump should be warmed up simultaneously. For feedwater pump with mechanic sealing, inner air should be exhausted adequately. (4) Middle tap on the main pump acts as desuperheating water of boiler reheater, the desuperheating water valve should be shut before starting, and it will be opened according to the requirement of boiler after starting. It is reverse while stopping pump. (5) During operation of variable speed pump, oil temperature of working oil cooler should be monitored except for temperature of lubricating oil. Spoon-type tube position of variable feedwater pump as linking standby should follow up automatically that of operating feedwater pump. If automatic following can’t be put into operation, spoon-type tube can be put above 40%. So water level of boiler drum can’t be too much fluctuant while operating pump trips. (6) While two variable speed pump operates in parallel, the differential between rotary speeds should be the minimum, preventing too much deflection of flow. (7) Temperature of discharged oil should not be 130℃, preventing fusible plug from melting.
5 Automatic Regulation and Protection of Feedwater Pump I. Automatic regulation of feedwater pump. Automatic regulation of feedwater pump can usually be split into two main parts: the minimum flow automatic regulation and feed water automatic regulation. 1. The minimum flow automatic regulation Feedwater pump is generally prescribed a permissible minimum flow (about 25%～30% of rating) while designing, if operating flow is less than the minimum, feed water will be boiled off due to rubbing heating, and water pressure in pump will be unstable, resulting in swing of balance disc or rather friction with balance foundation, if severely, disc foundation will be ruined or pump is blocked; Performance curve of centrifugal pump is flat in the range of small flow, or of hump type, so pressure pulsation will occur and results in ‘pant vibration’ phenomenon because of which water pressure is suddenly high or low and flow is suddenly heavy or low, in order to avoid this phenomenon, previously weighted automatic bypass valve (generally combined with outlet check valve) and recirculating tube were adopted. While flow is less than the minimum, standby valve overcomes the gravity of weighted hammer and automatically opens with the help of growth of outlet pressure of water pump, a part of feed water returns to deaerator or inlet of water pump via recirculating tubes. However, long dated practice proved that this method is not ideal because the recirculating flow controls the switch of standby valve only via the number of flow pressure drop and its setting value is difficult to control. And then outlet pressure of water pump is very high and pressure drop is very large with the condition of low flow, resulting in serious wear of standby valve which can’t close completely under the normal operation, leading no needed leakage and loss of power, and efficiency of water pump is reduced. Hence, modern high-speed pump is equipped with recirculating valve on the recirculating tube instead of weighted standby valve and multistage pressure-relief orifices as throttle equipment before the valve. Recirculating valve is opened via electromagnetic switching pneumatic switch by electric-contact signal of the minimum permissible flow in outlet flow meter, ensuring the minimum flow through water pump as well as avoiding wear of recirculating pump. 2. Feedwater pump of high pressure and capacity unit adopts variable speed regulation, its economy is better than throttle regulation, but, variable speed regulation exists the difference between “two sections” regulating scheme and “one section”, boiler feedwater regulator gives the signal in the former, so opening of feed regulating valve is changed firstly for water to suit the need immediately, then rotary speed of feedwater pump is changed via differential pressure regulator according to changing value of differential pressure of regulating valve (it is caused by changing of opening of regulating chamber), followed by outlet quantity of feedwater pump correspondingly until it is equal to feed water quantity needed by boiler, simultaneously pressure differential of regulating valve is restored as the constant value, the regulation is performed and operation will be resumed under the new balance condition.
In above regulating scheme, feed water can rapidly adapt the need of boiler through changing opening of regulating valve while load is changed, avoiding lack or fill of water caused by delay of regulation. But, the rapid adaptability is gotten with stationary differential pressure value of regulating valve, and it results in stationary loss in operation. Hence, the modern developing tendency is to cancel stationary differential pressure value of regulating valve, feedwater regulator (or three impulse pulse) gives off signal to directly change rotary
speed of regulating pump, only having “one section” regulation course, consequently economy of regulation of feedwater system is enhanced. Analyzing dynamic equation of hydraulic coupler drive variable speed feedwater pump, it is known that dynamic time constant mainly rests with inertia of changing of oil quantity in working chamber of hydraulic coupler, and this is relative with structure and regulating manner of hydraulic coupler. Because device inertia is small while hydraulic coupler and feedwater pump change torque, its impact on the whole dynamic time constant is less. It can adapt the need to feed water of boiler in time from theoretical calculating value. In order to reduce throttle loss of feedwater system and increase operation economy, the scheme “one section regulation” is feasible. II. Protection of feedwater pump Feedwater pump is a kind of important auxiliary device with complex structure; its safety and reliability should be ensured in operation. So high-capacity feedwater pump is equipped with many protection equipments, mainly as follows: (1) Feedwater pumps act as linking protection: once operating pump trips, standby pump can automatically put into operation to ensure that boiler feed water isn’t interrupted. (2) Protection of low oil pressure: feedwater pump adopts sliding bearing and forces oil circulation. So lubricating oil pressure should be kept as turbine. If oil pressure is too low, oil film will be broken, resulting in burning of pad. Protection of low oil pressure means that lubrication pressure links auxiliary oil pump in the prescribed value, maintaining oil pressure normal, if oil pressure is too low to maintain, the protection will link main pump to trip, ensuring that bearing pad isn’t ruined. In addition, for hydraulic coupler, while working oil pressure is low, auxiliary working oil pump should automatically link and start, ensuring normal working oil pressure. (3) Protection of high oil pressure: if oil pressure is too high, lubricating oil will leak from oil baffle, that isn’t safe either. Protection of high oil pressure can link to trip or lock auxiliary lubricating oil pump while lubrication pressure is more than the prescribed value. In addition, the protection can link to trip or lock auxiliary working oil pump while working oil pressure is too high. (4) Protection of high bearing temperature: some feedwater pumps, especially imported, are equipped this kind of protection. While temperature of bearing pad reaches the prescribed value, alarm signal will be sent out; if its temperature goes up continuously to the value of stopping pump, the protection will link to trip feedwater pump, ensuring the safety of bearing. Except for above, high-capacity feedwater pump are equipped with: main pump starting is locked if inlet valve isn’t opened; low pressure of outlet manifold locks opening of outlet valve, pump will trip if pressure differential of inlet screen of feedwater pump is large; an alarm will be given and pump will trip if water level of deaerator is low; protection of low flow of booster pump.
section7
LP Heater System Specifications
0-1 LP heater system specifications 1
Overview 1.1 The LP Heater System Specifications only applies to the Indonesia 2×300MW Coal-fired Unit Project. 1.2 In the Project there are set up two 300MW steam turbine units, which adopt eight-grade steam extraction, of which grades 5, 6, 7, and 8 are used for the four LP heaters respectively. In the water supply and heat recovery system, the LP heaters are numbered as 5#, 6#, 7#, and 8# based on the sequence of extraction pressure from high to low (see Figure 0-1-1 for the heat balance diagram), of which LP heaters 7# and 8# share the same shell (called conjunction LP heater). 1.3 The system layout for LP heater is detailed in Figure D300N-005019Q, and the system diagram is shown in Figure 0-1-2. In the system we only provide the balance vessels and magnetic liquid level displays. The LP heater system diagram is provided for information only, and the concrete arrangement and valve type selection depend on the project. 1.4 The installation, commission, and overhaul of LP heater proper are detailed in M706-021002BSM JD-1600-I LP Heater Installation and Operating Specifications, M708-017002BSM JD-600-III LP Heater Installation and Operating Specifications, and M709-017002CSM JD-600-IV LP Heater Installation and Operating Specifications. In the system specifications, the installation, commission, and overhaul for LP heater proper are not described.
2
System composition The system consists of the LP heater proper, feed pipe, normal drain line, accident drain line, extraction line, and water level display alarm and control equipment.
2.1 All LP heaters are of horizontal U-bend structure with a built-in drain cooling section, of which the conjunction LP heaters of 7# and 8# is set up at the condenser throat. 2.2 In the system the water supply bypasses consist of both big and small bypasses. LP heaters 5# and 6# adopt small bypasses, and they can step out solely; LP heaters 7# and 8# adopt big bypasses, but they can only step out simultaneously. 2.3The normal drainage for LP heater adopts a step-by-step gravity flow mode, that is, the drained water from LP heater 5# flows to LP heater 6#, and then to LP heater 7# and then to LP heater 8#, and then to LP heater 8#, and finally to the condenser. 2.4 Accident drain lines are set up for every LP heater. Under accident conditions or low-load working conditions, the drained water can directly enter into the drain
flash tank or condenser. 2.5 For every LP heater there are set up extraction pipes, which are used to extract the incondensable gas in the LP heater shell side. 2.6 Each LP heater is equipped with three single-chamber balance vessels, which output the water level changes in the LP heater. The changes are translated into 4~20mA electrical signals through a differential pressure transmitter and transmitted into the DCS. Then the DCS controls the opening of the drainage control valve of LP heater, which limits the water level of the LP heater within a normal water-level fluctuation range. The differential pressure transmitter and control valves shall be provided by the project as support devices, and the connection is shown as in Figure 0-1-3. 2.7 Every LP heater is equipped with a magnetic flap liquid level meter, which can display the variation of the water level in a LP heater and is equipped with a liquid level switch. The meter can output 4~20mA electrical signals for long distance transmission as alarm signals. The connection is shown in Figure 0-1-3. 3
System installation requirements 3.1 When the drainage control valve of a LP heater is fitted on a normal drain line, it shall be set up by approaching the drainage entry of the next grade LP heater. A bypass shall be set up for the drainage control valve for the convenience of overhaul. We recommend adopting not steam-liquid two-phase flow equipment but drainage control valves to control the water level of LP heater. 3.2 A accident drain control valve can be set up in a accident drain line. With regard to the arrangement of a accident drain line, we recommend that sole pipes leading to the condenser or drain flash tank shall be set up for the accident drain of each LP heater, and we do not recommend to combine the accident drain pipes to the drain flash tank or condenser. For the accident drain of LP heater 8#, when the drained water goes to the drain flash tank, the pressure of the tank can not be greater than that of LP heater 8#. 3.3For the continuous extraction pipe of each LP heater there shall be separate pipes leading to the condenser, and connecting all pipes in series or using one main pipe leading to the condenser is not allowed. It is best that the exhaust line is straight, so that the blocking from condensate accumulation and the resulting influence on the extraction of LP heater can be avoided. There shall be thermal insulation devices in the continuous extraction pipes to make it the least possible to block the extraction pipe by water. 3.4 There are stop valves set up in the continuous extraction pipes, and the users can reduce the extraction heat loss through adjust the valves’ opening. Setting up throttling orifice plate is also a good option, but when the plates are laid out, it shall be avoided that water is accumulated in both sides of the plates and affects the
exhaust. 3.5 The start extraction pipe near the shell of a LP heater can not be connected to the continuous extraction pipe of the LP heater. 3.6 In the feed water pipes there are set up safety valves with a set-pressure of 3.8MPa. The safety valves shall be mounted near the LP heater proper as much as possible. Beside LP heaters 5# and 6#, there are set up safety valves with a set-pressure of 0.6 MPa. In the discharge outlets of the safety valves there can not be no back pressure.
To deaerator
Figure 0-1-1 Indonesia project T-MCR working condition heat balance diagram
opening of steam turbine, including the pipe loss.
Note 2: The steam admission pressure of LP heater in the figure is the pressure in the extraction
Note 1: Flow rate, enthalpy, temperature, pressure
To condenser
pump pump
From condensate
The incondensable gas extracted from LP heater 5# entering into the condenser solely
Start or accident drain water of LP heater 5# entering into the drain flash tank solely
The incondensable gas extracted from LP heater 6# entering into the condenser solely
Start or accident drain water of LP heater 6# entering into the drain flash tank solely
The incondensable gas extracted from LP heater 8# entering into the condenser solely
The incondensable gas extracted from LP heater 7# entering into the condenser solely
Water supply (from condensate pump)
Start or accident drain water of LP heater entering into the drain flash tank solely
Start or accident drain water of LP heater entering into the drain flash tank solely
direction
Drained water 7# drainage (to 8# drainage inlet)
Figure 0-1-2 LP heater system diagram
Magnetic liquid level display connection sketch
Balance vessel connection sketch
Connected to the LP heater
Connected to the LP heater High level cut off
High water level
Alarm for high water level Single-chamber balance vessel High water level Normal water level Low water level
Connected to the LP heater
Alarm for low water level
Connected to the LP heater Differential pressure transmitter
4~20mA electrical signal
Figure 0-1-3 Magnetic liquid level display and balance vessel connection sketch
Chapter4 汽轮机油系统维护 section1
Specification for Lubricating system
0-1 Specification of Lubricating System 1 Overview The lubricating system of steam turbine adopts the oil supply mode of main oil pump-oil jet. The main oil pump is directly driven by the main shaft of steam turbine. Its outlet pressure oil drives the oil jet to engage in operation. The lubricating system is mainly used for serving the following purposes: providing lubricant to each bearing and jigger device of steam turbine generator set, some lubricant for the regulating system and protection system, sealing oil source for the hydrogen seal system of generator, adequate lubricant source for the shaft pushing up system of main shaft, cooling oil for the rotor coupling of steam turbine generator set. The system also has the smog exhausting function for oil return. The working medium of system is ISO-VG32 turbine oil.
2 System Composition The system mainly consists of main oil pump, oil supply jet, lubricant supply jet, AC lubricant pump, DC emergency oil pump, spill valve, concentrated oil box, oil smoke separator, oil level indicator, single flap check valve, double-flap check valve, oil cooler, switch valve, shaft pushing up device, low lubricant pressure shutoff device, set oil pipeline, electric heater, oil hydrogen separator (supplied by the motor factory) as well as connecting lines, monitoring instruments, etc. Refer to the attached diagram for the system diagram.
3 Brief Introduction about Main Devices in System 3.1 Main Oil Pump The oil pump is of single-stage double suction centrifugal type, which is installed in the front bearing box of steam turbine set. The pump shaft and main shaft of steam turbine adopt rigid connection that is directly driven by the steam turbine rotor. It provides power oil for the oil supply jet and lubricant oil jet. Major parameters are in the table below. Oil Pressure at Suction Port of Main Oil Pump
0.09～0.12 MPa
Oil Pressure at Outlet of Main Oil Pump
1.75-1.85 MPa
Rated Speed of Main Oil Pump
3000 r/min
Flow
>3000 L
Power Consumption
～200 kw
Refer to “Specification of Main Oil Pump” for the detailed description (M109-511000ASM)
3.2 Oil Jet The oil jet consists of oil supply jet (No.I) and lubricant supply jet (No.II). The jet nuzzle is porous. There is a plate in the suction chamber of oil jet to stop the reverse flow of sucked oil flow. See the table below for the characteristic parameters: Name
Outlet Pressure
Outlet Flow
Oil Supply Jet (No. I)
0.21 MPa
3447 L/min
Lubricant Supply Jet (No.II)
0.31 MPa
3600 L/min
Refer to “ User’s Manual for Oil Jet” for the detailed description (D300N-505000ASM). 3.3 Concentrated Oil Box The oil box adopts a concentrated mode. That is to locate various devices in the lubricating system in the oil box, such as AC lubricant pump, DC emergency oil pump, single-flap check valve, double-flap check valve, oil smoke separator, oil level indicator, oil jet, electric heater, spill valve, internal pipeline, etc. It facilitates operation and monitoring, simplifies the arrangement of power station and is convenient for fireproofing. During normal operation, the capacity of oil box is 30.6 m3。 The details about the concentrated oil box can be found in the “Operation Instruction of Concentrated Oil Box” (D300N-501000ASM). 3.4 AC Lubricant Pump The pump is single-stage single-suction vertical electric centrifugal oil pump and the model is 125LY-35-4. It supplies sufficient lubricant to each bearing, jigger and shaft pushing upof steam turbine set during the start-up and shutdown as well as when the lubricant pressure is lower than 0.05MPa. The drive motor is explosion proof motor. The characteristic data are as follows: Delivery Lift
35 m
Speed
2950 r/min
Motor Power
45 kw
Flow Power Supply
3000 L/min AC 380V
The details can be found in the “ Installation and Operation Instruction of Model 125LY-35-4 Lubricant Pump” supplied with the machine. 3.5 DC Emergency Oil Pump The pump is single-stage single-suction vertical electric centrifugal oil pump and the model is 125LY-23-4. It is only used during the shutdown of steam turbine set. It supplies lubricant to each bearing when the lubricant pressure is lower than 0.04MPa or the AC power is down to ensure the safe shutdown of steam turbine set. The drive motor is DC motor. The characteristic data are as follows:
Delivery Lift
23 m
Speed
3000 r/min
Motor Power
22 kw
Flow Power Supply
2600 L/min DC 220V
The details can be found in the “ Installation and Operation Instruction of Model 125LY-23-4 Lubricant Pump” supplied with the machine.
3.6 Spill Valve The spill valve is of spring-type, which is installed in the oil box and located on the mother pipe of lubricant at the rear of oil cooler outlet. It is used to adjust the pressure of lubricant in the mother pipe to ensure the inlet pressure of bearing and keep the flow stable so as to sufficiently and reliably supply lubricant to the entire lubricating system. The characteristic data are as follows: Normal Oil Spill Flow
100 L/min
Min. Oil Spill Flow Max. Oil Spill Flow
Normal Oil Spill Pressure
0.196 MPa
0 L/min
Min. Oil Pressure
Spill
0.176 MPa
500 L/min
Max. Oil Pressure
Spill
0.255 MPa
The details can be found in the “ Operation Instruction of Spill Valve” (M536.X01SM).
3.7 Oil Cooler There are two sets of oil coolers in the lubricating system, which are tubular type heat exchangers. The model is YL-180-2. When one is running, the other is for backup. It uses circulating water as the cooling medium, which takes away the heat resulted from the friction of bearing. The characteristic data are as follows: Cooling Area
180 m2
Inlet Oil Temperature
60℃
Cooling Water Capacity
336 t/h
Outlet Oil Temperature
45℃
Cooling Water Capacity
180 t/h
Cooling Water Temperature
33℃
The details can be found in the “ Installation and Operation Instruction of Model YL-180-2 Oil Cooler” (M720.X07SM). 3.8 Oil Smoke Separator There is a set of fume extractor in the system, which integrates the smoke discharge fan and the oil smoke separator. It is vertically installed on the cover of concentrated oil box. It creates negative pressure in the oil return tube, oil box and oil return chamber of each bearing box to ensure smooth oil return and separate the mixture of oil smoke. It discharges the smoke and sends the oil drops back to the oil box to reduce environmental pollution and ensure the safety and reliability of oil system. At the same time, in order to prevent too high negative pressure in the chamber of each bearing box, the fume extractor is designed to accommodate a set of air doors to control the smoke discharge and maintain the negative pressure in the bearing box at 1Kpa. Otherwise, it will cause the leakage of shaft seal of steam turbine, thus the steam will flee into the bearing box and the water will get into the oil. The details can be found in the “ Operation Instruction of Oil Smoke Separator” (M519.X02SM). 3.9 Switch Valve The switch valve is of cylindrical plate type structure, which is installed between the two oil coolers. It switches the two oil coolers and parallel them if necessary. The characteristic data are as follows:
Model
FQ-5-250-1
Nominal Diameter
250
Working Pressure
0.4MPa
Max. Working Temperature
80℃
The details can be found in the “ Operation Instruction of Model FQ-5-250-1 Switch Valve”(M765.X02SM). 3.10 Electric Heater There are 6 electric heaters installed in the concentrated oil box with total power of 60KW and voltage of AC 220V. If the oil temperature is lower than 10℃ before the start-up, the heaters are switched on; when the oil temperature rises to 35℃, the heaters are turned off. 3.11 Shaft Pushing up Device This device is mainly used to supply high pressure oil to each bearing during the start-up, shutdown and jigger, which forcibly pushes up each shaft neck and forms static pressure oil film between the neck and bearing to eliminate the dry friction between the neck and bearing. The details can be found in the “Operation Instruction of Shaft Pushing up Device” (D300N-601000ASM).
4
Operation of Lubricating System
4.1 Start-up State Before the start-up of system, it is necessary to confirm whether the oiliness meets the cleanliness requirement for the start-up. The oil level in the oil box shall be at the highest oil level. Switch off the cooling water valve for the oil cooler. Heat the oil and start the AC lubricant pump when the oil temperature meets the start-up requirements for the oil pump. Switch on the smoke discharge fan to forcibly circulate the lubricant. When the oil temperature reaches 35℃, start the cooling water valve of oil cooler to get the oil cooler engaged, then start the oil pump of shaft pushing up device and adjust the pushed up height of each bearing neck to the designed valve. After these, it is ready to put the jigger into operation. When the set speed reaches 1200 r/min, the shaft pushing up device can be removed (the power plant can also regulate the speed of shaft pushing up device according to its operational experience). During the period of raising speed, the AC lubricant pump shall work normally and provide lubricant to the set. When the set reaches 3000 r/min and gets stable, the AC lubricant pump can be stopped. Finally, adjust the spill valve to keep the oil pressure in the mother pipe within the set value. 4.2 Normal Operation State During normal operation, all the high pressure oil in the system is supplied by the main oil pump located in the front bearing box. The high pressure oil from the main oil pump serves as the dynamic oil source of oil jet. The oil jet sucks the oil from the oil box. No. I oil jet provides the oil source for the main oil pump while No. II oil jet supplies oil to each bearing, jigger and hydrogen seal system for the purposes of lubricating, cooling and sealing. During normal operation, it is necessary to adjust the cooling water flow of oil cooler according to the oil temperature of lubricant mother pipe so as to control the inlet oil temperature of bearing within the set value. 4.3 Shutdown State When shutting down the set under normal or emergent ( tripping ) condition, the AC lubricant pump shall be started before the speed of steam turbine drops to 2850 r/min; when it drops to 1200 r/min, the shaft pushing up device shall be started. If the AC lubricant pump fails to react, the DC emergency oil pump shall be combined to ensure safe shutdown. During the jiggering, the shaft pushing up device and AC lubricant pump can only be stopped after the jigger is stopped.
5 Introduction about Oil Return System The system adopts a set pipeline with 2 mother pipes of return oil. The return oil of front bearing box goes to the set pipe through two oil return tubes at the lower part of front bearing box and gets back to the dirty oil compartment in the oil box. The return oil from the other bearing boxes goes to the set pipe through respective branch tubes and gets back to the dirty oil compartment in the oil box. The oil drain from the shaft pushing up device returns to the oil box. The mother pipe of return oil shall be installed towards the direction of oil box with a gradually descendant grade of slope that is 1%~3%. The return oil in the return oil tube shall be half full to facilitate the oil smoke in each bearing box to flow to the oil box through the space over the oil surface. Then the oil smoke is separated by the fume extractor and discharged into the atmosphere. The return oil from the bearing of generator shall go through oil hydrogen separation before it is connected to the mother pipe of return oil. Otherwise, it will endanger the set. The return oil from each bearing box flows back to the dirty oil compartment in the oil box. After it is filtered, it goes to the clean oil compartment in the oil box. There are oil level indicators separately installed in the dirty and clean oil compartments. The unobstructed degree of sieve can be judged through the difference of oil levels in the two oil level indicators. When the difference exceeds 100mm, the sieve shall be cleaned.
6 Maintenance of Lubricating system 6.1 During normal operation, the normal outlet oil pressure of main oil pump is 1.8±0.05MPa. When it drops to 1.65MPa, the AC lubricant pump shall be started. The root cause shall be investigated and the machine shall be ready to shut down. 6.2 There shall be interlock protection among the pressure signals of AC lubricant pump, DC emergency oil pump and lubricant mother pipe. When the steam turbine is in normal operation, the pressure of lubricant flowing into the bearing shall be 0.08~0.12MPa. When the pressure drop at the midsplit surface of bearing in the steam turbine reaches 0.049 MPa, the alarm will be turned on and the AC lubricant pump will be started. After the start-up of AC lubricant pump, if the pressure drop of lubricant continues, the brake shall be switched off. During the shutdown, when the pressure drop of lubricant at the midsplit surface of bearing in the steam turbine reduces to 0.0392MPa. The DC emergency oil pump shall be started and the cause of oil pressure reduction shall be checked immediately. Every half month, the test of interlock protection with low oil pressure shall be performed. 6.3 Lubricant Temperature The system adopts ISO-VG32 steam turbine oil. The set bearing requires the inlet lubricant temperature to be 40℃~46℃. The normal temperature of return oil of bearing shall be less than 65℃. During normal operation, the cooling water flow for the oil cooler shall be adjusted according to the lubricant mother pipe to ensure the inlet oil temperature. 6.4 Oil Level in Concentrated Oil Box
Before shipping, the middle position between the highest and lowest oil levels shall be set as the zero position according to the oil level requirement on the drawing of concentrated oil box. It will be the normal oil level for the oil level indicator. During normal operation, the highest oil level is +250mm and lowest –250mm. The first fill in the concentrated oil box shall be about 35m3. Before the normal start-up, the oil level in the oil box is at the highest oil level. When the nested oil pipeline with longer horizontal section is used, the operating oil level in the oil box will be lower than the zero position. It is a normal phenomenon.
7
Requirements for Lubricating System 7.1 The installation requirements for the lubricating system shall meet Article 248-278 in SDJ53-83--“ Technical Specifications for Power Construction and Acceptance” (Steam Turbine Set Part) and “ Technical Provisions for Lubricating System Installation” set by the manufacturer. 7.2 The requirements for the oil circulating rinsing of lubricating system shall meet Article 533-547 in SDJ53-83---” Technical Specifications for Power Construction and Acceptance” (Steam Turbine Set Part) and “ Technical Provisions for Lubricating System Rinsing” set by the manufacturer.
D300N-000152ASM
Lubricant for Jigger
Main Oil Pump Low Pressure Cylinder
HIP Cylinder
Generator
Technical Requirements
To Security Part
1.
Cooling Oil for Coupling Ø38X2.5
The details about the connection between the lubricant supply pipe and the pipeline of hydrogen seal system of generator part (supplied by the motor factory) are in the
Cooling Oil for Coupling Ø38X2.5
diagram of hydrogen seal oil system of generator of DFSTW. 2.
The return oil from the generator and hydrogen seal system must go through dehydrogenization before entering into the system.
3.
Oil Hydrogen Separator ( supplied by the
Set Oil Pipeline
When filling the oil box to the maximum oil level, the external pipeline of oil box, oil cooler and oil purifying device shall be filled first.
4.
The filter cloth of movable sieve shall be
To Hydrogen Seal System
installed during the oil circulation and
Oil Level Indicator
removed after the oil quality becomes good.
Shaft Pushing up Device 5.
The drawing number of each part in the diagrams for each project is in relevant project delivery list.
6.
The details about the pipe connection between the system and the lubricant
Electric Heater
storage and disposal system can be found
Concentrated Oil Box
in the oil disposal system diagram. The lubricant storage and disposal system shall be purchased by customers.
Water Filter
Spill Valve
To Vacant Side of Generator
Circulating Cooling Water
Oil Charge Valve of Oil Cooler
Oil Suction Interface of Seal Oil Pump
Summary of Air Pressure Measuring Points
Oil Jet Oil Cooler
Oil Cooler
No.
Point Name
Qty
Switch Valve
DC Emergency Oil AC Lubricant Pump
Stop Valve
Oil Pipeline
Oil Suction Pipeline of Main Oil Pump
Drain Lubricant Pipeline
Check Valve
Three Valve
Way
Spill Valve
Explanatory Legend Air Sm Concentric Reducer
Peep Tube
Centrifugal Oil Pump
Radial Oil Jet
Sieve
Throttle Plate
Thrust Bearing
Exhaustion Air
Slide One-way Valve
to Drain
Oil Supply Pipeline Movable for Shaft Pushing up Sieve
Smoke Discharge Fan
Pressure Gauge
Thermometer
Meter
Range
Lubricant Storage and Disposal System
Pressure Oil Pipeline
Point
1
Outlet Pressure of DC Lubricant Pump
1
0-0.5MPa
2
Outlet Pressure of AC Lubricant Pump
1
0-0.5MPa
3
Outlet Oil Pressure of Main Oil Pump
1
0-0.5MPa
4
Outlet Oil Pressure of Oil Supply Jet
1
0-3.0MPa
5
Outlet Oil Pressure of Lubricating Jet
1
0-0.5MPa
6
Outlet Oil Temperature of Oil Cooler
1
0- 100℃
7
Inlet Oil Temperature of Oil Cooler
1
0- 100℃
Check Valve
Low Lubricant Pressure Switch Temperature Pressure Alarm or Switch
supplied with shaft pushing up device
8
Outlet Oil Pressure of Oil Pump for Shaft Pushing up
1
0-20.0MPa
supplied with shaft pushing up device
0-1-10
section2 Description of integrated oil tank 0-1 Description integrated oil tank 1. Integrated oil tank general The used oil capacity and oil tank volume in oil system increases as the unit capacity. In order to make the equipment arrangement in oil system compact and convenient for installation, operation and maintenance, this oil tank adopts integrated type to improve the safety and reliability of operation for supply oil system of unit.
2.
Brief introduction of structure The integrated oil tank is rectangle vessel welded by section bar, such as steel sheet, I beam. In order to withstand the self-weight and oil weight of oil tank as well as the weight of equipment, supporting plate is welded on the bottom of case, and reinforcing rib plate is welded on the external side and external end face, I beam is welded on the cover board to strengthen the steel rigidity and ensure the equipment on the cover board operating normally. The guardrail is provided at the top of oil tank. Two cylindrical strainers are provided in the oil-return chamber inside oil tank to prevent the clean oil zone of oil tank from foreign matter. This filter cartridge is cylindrical type with inner and external layers to ensure the clean oil zone free of foreign matter during cleaning the inner filter cartridge. The filter area of external filter cartridge shall not be cleaned during the unit overhaul. The bottom of external filter cartridge connects with the glass liquid-level gauge outside the oil tank to monitor the level and oil quality state and remove the impurities. One AC lube oil pump, one DC emergency oil pump are provided on the cover board of oil tank (see drawing 0-1-2). The oil level height in the oil tank shall be enough to ensure the suction inlet of two oil pumps immerging sufficient depth under the oil surface so that the oil pump has sufficient suction height to prevent the oil pump from cavitations erosion. The return oil shall return to oil tank through pipe at normal oil level before strainer to minimize the disturbance caused by the return oil. The air and impurities carried by return oil can be separated from oil through long return oil distance to ensure the oil with well quality. Demister is equipped at the top of oil tank and integrates the fan with separator. The fume discharge outlet is upwards to extract the fume from oil tank and separate the oil and fume. The demister makes the oil without deposit back to oil tank, and the oil drain piping drain the oil with deposit to slush tank. In order to monitor the oil level in oil tank, one ultrasonic oil level detector is provided at the top of the oil tank. In addition, the interface of tube-in-tube oil pipe is mounted at the top cover of oil tank. This oil pipe is divided into two ways, one is tube-in-tube oil pipe to front bearing housing and anther is tube-in-tube oil pipe to rear bearing housing and motor bearing. This design will prevent the various pipes in tube-in-tube pipe twist each other and make the oil flow smoothly as well as with small oil resistance loss. I# oil injector and II# lube injector, oil overflow valve, single/double tongue check valve on piping and inner pipe are equipped inside the oil tank. 6 electrical heaters and 2 thermocouples are equipped on the oil tank. Start the electrical heater in case the oil temperature is less than 20℃ and start AC
lube oil pump while heating the oil to 20℃. Various interfaces and emergency blow-down port, oil overflow port of oil tank and interface for flushing device connected with other oil system equipment are equipped at the side and end of oil tank (see drawing 0-1-3). The measuring pressure hole is equipped at the cover of oil tank to connect with the various interfaces on the control instrument cabinet box. The instrument cabinet is installed in integrated oil tank on site. Monitor and control the operation of oil system and various equipments. The tube clip is equipped on the cover of oil tank to fix the monitoring tube of oil pressure and prevent it from vibration. The manhole cover plate on the cover of oil tank is push-draw type to make the maintenance personnel entry the oil tank easily for check.
3. Operation of integrated oil tank The max operating volume of this oil tank is 35m3, and the normal operating volume is 30.6m3, the net weight of oil tank is of 20000kg. The oil level of the tank during shutdown shall be higher than that during the unit normal operating. The increased value of oil level is based on the oil storage capacity of oil supply pipe and return oil pipe at actual oil level above. The majority oil in the oil supply pipe and oil return pipe return oil tank. The oil level variation can be observed through the use of ultrasonic oil level detector located at the top of the clean oil zone of oil tank. The oil level in the clean oil zone is kept at between low oil level and high oil level during the unit operating normally. Certain negative pressure is formed in the return oil pipe and oil tank by the extraction function of fan to facilitate the return oil return oil tank at once and prevent the oil or fume from overflowing, make the whole lube system operate at safe state. The negative pressure in oil tank shall be kept within the negative 1kPa. The oil temperature in tank shall be below 65℃ during operating.
4. Maintenance of integrated oil tank 4.1 The oil pump, fan and other equipment of oil system shall be kept at well operating state. 4.2 The inner surface of oil tank shall be cleaned by cloth instead of cotton yarn or other floss. 4.3 Forbid impurities and solid matter into oil tank to avoid the great accident occurring. 4.4 The oil tank shall be sealed to prevent the air entry and form positive pressure. 4.5 Forbid the fire around the oil tank. 4.6 The strainer of oil tank shall be cleaned periodically. 4.7 The integrated oil tank shall be cleaned and checked completely during the unit overhaul. 4.8The operation, maintenance and inspection of equipment located on the oil tank refer to various equipment instructions in detail. 5
Monitoring of oil quality
The GB11120-89 L-TSA32 turbine oil can be used for this oil tank. The oil quality has a direct effect on normal working of system and safe operating of various equipments in oil system. The following items must be performed seriously: 5.1The periodic test must be done for oil quality in oil tank to filter the impurities and water from oil. 5.2 The oil purifier in system must be put into continuously or periodically. 5.3The oil level must be recorded every day. In case the oil level changes greatly, the reason must be found; In case the water or fire-resistance hydraulic oil mixes into turbine oil tank, it must be filtered to prevent oil contamination and cut off the contamination source. 5. 4 The stand-by oil storage equipment, piping, emergency oil storage tank must be cleaned free of oil contamination. 5. 5 In case the ageing phenomenon is found in turbine oil, it must take measures to replace the oil. 5. 6 In case the T501 anti-oxidant in oil is less than 50% of new oil, the oil must be added to the standard of new oil. 5. 7In case the water in oil is greater than 0.05% or the destructive emulsifying time increases fast, the purifier must be started. 5. 8 The T746 preservative and 902 antifoam agents must be added into turbine oil.
guardrail
Blow-down mouth
Oil port for hydrogen sealing
ladder
Check mouth of oil cooler
From cooler
To oil cooler Figure 0-1-1
oil
Suction oil mouth for flushing device
Filter cartridge
anhole
Mark
Electrical heater
Ultrasonic oil level detector
Access
hole
Thermocouple
Tube clip
Tube
of
overflow oil valve
I access hole of oil
II access hole of oil
injector
injector
Fume discharge i
Pressure measuring port
Safety door
Fume outlet
Figure 0-1-2
discharge
Demister
Oil
overflow Return-oil port of oil purifier
Oil suction of oil purifier
stand-by valve for oil of hydrogen sealing
Emergency oil discharge outlet
Figure 0-1-3
section3 1.
Manual of shaft-jacking device
Purpose The shaft-jacking device is an important assembly in turbine. It functions as jacking rotor at turning warm-up and even decreasing temperature during the unit start-up and showdown. HP shaft-jacking oil pocket is provided for elliptical bearing of steam turboset. The HP oil provided by shaft-jacking device forms static pressure oil film between rotor and oil pocket of bearing to jack the rotor forcedly and prevent the dry rub between journal and bearing bush from as well as decrease the turning moment during the steam turbine with low speed, it. It also plays an important role in protecting the unit, especially for rotor and bearing. During operating, the pressure in shaft-jacking oil pocket represents the oil film pressure of bearing and used as one of important measures to monitor the elevation variation of shaft system and load division of bearing. Working oil:ISO-VG32 Turbine oil
2
Structure This device consists of some assemblies, such as motor, HP oil pump, auto reverse-flushing filter, dual-cylindrical filter, plate filter, pressure relay, over-flow valve, one-way throttle valve etc. and stainless steel tube, attachment (see drawing 0-1-1). The integrated type is used for this device to facilitate installation and maintenance. In order to prevent the pump cavitations and protect system, the LP oil supply (positive pressure oil＜0.4Mpa＝ is adopted for inlet of system. The LP oil enters the pump suction oil port through reverse-flushing oil filter and dual cylindrical oil filter. The HP oil pumped enters various distributors and arrives at relative shaft-jacking oil port to jack the shaft. Various outlet flow of distributor is regulated by single-way throttle valve. The overflow valve regulates the safe pressure at pump outlet. The overflow valve limits the oil pressure of main to prevent the oil pressure of oil supply system from exceeding the max allowable value. The system adopts the oil filter with two-stage suction to ensure the cleanliness of system. The oil pump is a imported plunger pumps with high efficiency, low heat output, low noise, reliable continuous operation under high pressure, without leakage and the volume efficiency above 95%. The coupling with compensation and high precise connecting transition frame are equipped between motor and pump to decrease the vibration, noise of whole generator set of oil pump and ensure the system with well and reliable integral performance. The instrument panel located at the front of shaft-jacking device is used for monitoring the shaft-jacking oil pressure of various bearings and oil film pressure at shaft-jacking pocket during the unit at normal operation. In order to control the operation and switch-over of two shaft-jacking oil pump, pressure relay is provided for two plat filter; The pressure relay is provided for inlet piping of oil pump to ensure the required inlet oil pressure during the shaft-jacking device starting-up. One pressure meter is equipped before and after the auto reserve-flushing filter to monitor the pressure difference value. It shall be cleaned according to the case. The tube-in-tube oil pipe is used for the pressure oil pipe and suction oil pipe of shaft-jacking device.
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3. Technical parameters of main equipment 3.1 Imported plunger pump: Model A10VSO100 P>16MPa Q=60 l/min
n=1480r/min
3.2 Motor: Model YB250M-4 anti-explosion motor V=380V
N=55 kW
n=1480r/min
Installation mode B3
3.3 Dual cylindrical filter: Model 3PD110×250A25C-1 PN=2.5MPa
Q=980 l/min
Filtering accurate :25μm Setting value of pressure difference :0.05MPa 3. 4 Plate oil filter: model 9PP80×250A10C-1 PN=40MPa
Q=390 l/min
Filtering accurate:10μm Setting value of pressure difference: 0.35MPa 3.5 Auto reactive-flushing oil filter: model ZCL-I Q=450 l/min
Filtering accurate:45μm
3. 6 Oil overflow valve: Model DB30-2-30/315 PN=32MPa 4
Qmax=600 l/min
Installation
4.1 The connection between shaft-jacking device and unit refer to D300N-002004A Lube oil system diagram. The pickling and phosphatizing treatment shall be performed for all piping connected with shaft-jacking device. Any dirty and mechanical impurities in the piping shall be removed and its cleanliness shall conform to the clean-2 requirement in JB/T4058-1999 Cleanliness standard for steam turbine. 4.2 The tightness of piping shall be checked and the oil cycle flushing shall be performed together with lube oil system after installing the shaft-jacking device. It must be careful to protect the precise elements in shaft-jacking device during oil cycle flushing. 4. 3 This system is an integral system. The lifting bolt on the base seat and the lifting hole on the side of base seat are used during lifting. The lifting shall be stable, safe to avoid various elements, instrument, piping from damage and deformed. In order to prevent impact, it shall be put on the ground slightly. This device is mounted on the reinforced concrete and fixed with 8-M24 anchor bolt. The environment around the device shall be dry, well venting quality. 5
Commissioning
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5. 1 Check the strainer of filter to determine whether is required to replace strainer after finishing oil cycle. The 10litre turbine oil is injected into pump casing through oil discharge outlet of oil pump. 5. 2 Open the valve on the inlet oil pipe and inlet oil pipe. 5. 3 Turn the coupling in manual to check its rotation whether is smooth and remove the air in the pump. 5. 4 Full loosen (counter-clockwise rotation) the constant pressure variable valve located on the pump. 5. 5 Inching the motor to check the rotating direction of motor whether is correct. The pump is at unloading state and the motor starts with no-load. Inching the opening of the stop valve at the oil discharge outlet of reverse flushing oil filter to ensure the pressure difference △P = P3 - P2 = 0.12 ～0.18Mpa (i.e. the difference between outlet oil pressure and oil discharge pressure of reactive-flushing oil filter), and monitor the working frequency of blow-down mechanism with one “click” per second. 5. 6 Start-up the motor to check the rotating whether is normal and has any noise and leakage during the device operation. 5. 7 Close the throttle valve located on the flow divider. 5. 8 Rotating clockwise the constant pressure variable valve and oil overflow valve to increase the outlet pressure of pump to 16Mpa, and set the action pressure of oil overflow valve at 16Mpa. 5. 9 Rotate counter-clockwise the constant pressure variable valve to decrease its pressure to 14Mpa. Start the motor after the valve operating normally. 5.10 The macrometer is used for measuring the position of the journal top before jacking, then open the single-way throttle valve side by side to make each journal jacking height within 0.02mm～0.05mm, and record each jacking oil pressure and the jacking height of journal. 5.11 The turning gear can be put into operation after adjusting the jacking height of various journals at acceptable value, and then observe the rotating of turning gear and steam turboset rotor whether is normal. 5.12 The acceptance test shall be performed after finishing the above work and the shaft-jacking device is allowed to put into operation. 6
Putting into of shaft-jacking device
6. 1 Start the shaft-jacking oil pump before starting the turning gear during starting the steam turbine, then put into shaft-jacking device. 6. 2 Start the shaft-jacking device, and then put it into operation to prevent low speed burn-out while the speed of steam turbine decreasing to 1200 r/min and steam turbine shutdown. The shaft-jacking oil pump must be stopped while the speed of steam turbine rising to 1200 r/min. 6. 3 The shaft-jacking device can also be started, in case the rotor is required to rotate at static status and the oil system with enough inlet oil pressure to jack the oil pump. 6. 4 If there is any difference between the putting into, stopping of shaft-jacking device and that of steam turbine start-up operation instruction, the latter be regarded as the criterion.
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7
Working process and parameter
7.1 The suction oil pressure is of 0.2Mpa after the suction oil of shaft-jacking device taking from oil cooler. The suction oil is filtered roughly by one 45μm auto reverse-flushing oil filter and enter jacking oil pump through dual cylindrical oil filter. The outlet pressure of jacking oil pump shall be 16.0Mpa and controlled by oil overflow valve. The pressure oil from oil pump shall pass through 10μm plate filter to ensure the cleanliness of jacking oil. The pressure oil enters the flow divider through plate filter; finally enters various bearings through single-way throttle valve and single way valve. The said oil capacity and oil pressure can be controlled by means of adjusting single-way throttle valve to ensure the jacking height of journal within the reasonable range(theoretical calculating: The jacking height shall be greater than 0.02mm, in case the jacking oil pressure of journal is of 8～14Mpa). 7.2 Control of shaft-jacking device The pressure relay with power supply AC 220V is the key instrument used for start/shutdown of shaft-jacking device.
PS1, PS2 monitor the inlet suction oil pressure of jacking oil pump. In case the
inlet oil pressure is less than 0.03Mpa, the pressure relay is off. PS3, PS4 monitor the outlet oil pressure of jacking oil pump. In case the outlet oil pressure is less than 7Mpa, the pressure relay is off. 7.3
Switch-over of oil pump Two HP oil pumps are equipped for this device, one for operating and the other for stand-by. In case one pump or motor fails, the stand-by motor is started to complete the switch-over process.
8.
Maintenance
8.1 When the dual cylindrical filter sends the signal through setting value of pressure difference during debugging and putting into operation, filter cartridge must be cleaned or replaced. During replace the filter cartridge, the switch-over of dual-cylindrical filter can be finished by means of turning the filling valve of filter to stand-by cylinder and opening the blow-off valve of stand-by cylinder, screwing the blow-off valve tightly and turning the change-over valve to stand-by side. The blow-down port of reverse-flushing oil filter shall be cleaned during the system stopping. In case the inlet/outlet pressure difference is greater than or equal to 0.08MPa during using, the reverse-flushing oil filter shall be cleaned and checked after stopping, opening the upper cover, exhausting the oil in the filter completely. 8. 2 The tightness of piping shall be checked for shaft-jacking device constantly to keep the well sealing. The oil pump and oil filter shall be filled constantly, and the press button and switch shall be dry and with well contact to ensure putting into operation at any time. 8.3 The air in oil filter and oil pump shall be exhausted completely during the first starting after installing or dismantling, maintaining to prevent the shaft-jacking device and oil pipe not pumping oil or the oil with bubble and finally effecting the jacking. 8.4 The cleanliness of working oil shall conform to the operation requirement of unit (NAS8class). 8.5 Check periodically; calibrate pressure meter and pressure relay. Check periodically the performance of various sealing parts whether is well. The troubles can be removed in time.
- 183 -
8.6 The jacking oil pressure shows the operation of shaft-jacking device whether is normal. After starting various jacking oil pressure shall be in the range of 8～14Mpa. In case the oil pressure is too high, it means that the rotor shall not be jacked fully and HP oil discharge is blocked. In case the oil pressure is too low, it means that the oil leakage shall occur in HP oil piping system. While the shaft-jacking device has been started but the shaft is not yet jacked, the oil jacking pressure will rise instantaneously. When the shaft is jacked and after the oil discharge is smooth, the oil pressure shall decrease at a stable value, the pressure at this time indicates the normal jacking pressure. 9
Requirement of shaft-jacking device
9.1 The shaft-jacking device shall be installed according to the Article 248～278 in SDJ53-83 Specification for electric power construction and acceptance (steam turbine unit volume). 9. 2 The oil cyclic flushing for shaft-jacking device shall be performed according to Article 535～547 in SDJ53-83 Specification for electric power construction and acceptance (steam turbine unit volume) and Specification of flushing technology for oil system of manufactory. 10 Common trouble analysis 10. 1 Abnormal noise of pump Check the oil flow of suction oil port for pump whether is enough and the check valve whether are open and the oil filter whether is blocked. 10. 2 The reason for the pressure of system fails to rise (1) Check the regulating pressure of overflow valve whether is proper and flexible. (2) Check the max. setting value of pump whether is up to proper height (refer to the pump stylebook) (3) Check various regulating valve of system whether full opens. 10. 3 Fluctuation of various outlet pressure of distributor (1) The pressure fluctuating is related to the load size at various outlet.. (2) The pressure fluctuating is related to the opening of throttle valve. The throttle bar of corresponding valve can be regulated. 11. This factory shall reserve the right to replace the original design by better element and material.
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section4 1
Manual of oil injector
General The oil injector is one of the important equipment in lube oil system for steam turboset. The oil injector of lube oil system of steam turboset is divided into oil supply injector, lube oil supply injector according to its working purpose. The working medium is of L-TSA 32 turbine oil and the working oil temperature is of 45℃～65℃. The unit shall be put into operation in case the speed of unit reaches or approaches the rated speed.
1.1 Oil supply injector During the unit at normal operating, the oil supply injector can supply sufficient oil for main oil pump, and partial pressure oil at main oil pump outlet serve as its power oil with pressure 1.96Mpa (gauge pressure) and nozzle flow 1266 l/min, outlet oil pressure 0.2Mpa (gauge pressure) and outlet oil capacity 3179 l/min. 1.2 Lube oil supply injector During the unit at normal operation, the lube oil supply injector can supply the lube oil for various bearing of steam turbo-set, and partial pressure oil at main oil pump outlet serve as its power oil and partial oil of its power oil with pressure 1.96Mpa(gauge pressure), nozzle flow 1913 l/min, outlet oil pressure 0.32Mpa (gauge pressure), outlet oil capacity 3600 l/min. 2. Oil injector adjustment The performance test and adjusting has been performed for oil injector to meet the design requirement before ex-working. So the oil supply injector and lube oil supply injector can’t be adjusted in power plant. It is difficult to distinguish from appearance due to the outline of oil supply injector same as that of lube oil supply injector. Therefore, the both injector can be distinguished by #I and #II symbol marked on the installation indicating board of diffusion tube in appearance. #I shows oil supply injector and #II shows lube oil supply injector. The both oil injector can be distinguished by inner dimension,i.e.5-Φ9.6mm for nozzle hole and Φ76mm for throat diameter of diffusion tube of oil supply inject; 5-Φ11.8mm for nozzle hole dimension and Φ70mm for throat diameter of diffusion tube of lube oil supply injector, 3
Structure description The oil supply injector consists of multi-hole nozzle, diffusion tube, sleeve and strainer same as the lube oil supply injector in structure (see attached drawing 0-1-1). The pressure oil jets out with high speed through nozzle and forms certain negative pressure in suction chamber. The turbine oil in oil reservoir flow into oil injector under the action of pressure difference, then enter into diffusion tube carried with high-speed power oil. - 185 -
The power oil in diffusion tube mixes with the suction oil completely to meet the required pressure value and flow value. 4.
Assembly and installation The installing of oil injector has significant effect on performance. The nozzle support and the flange of inlet oil tube must be tightened during installing the nozzle of oil supply injector and lube oil supply injector to ensure the HP oil against leakage. The flatness and fineness of all joint surfaces must be well.
5.
Maintenance In case the oil injector isn’t used immediately after arriving in site, it must be sealed with grease. In case the oil injector isn’t installed after arriving site within two months, it must be dismantled to remove rust and dirty before installing. During the unit overhaul, the oil injector is required to dismantle for checking, especially for nozzle. The surface roughness of nozzle bore shall be , . In case there is any scripting or recess area, it must be replaced. The possible failure and solve method is as follows :( see table 1)
Failure Oil injector outlet without flow and pressure oil injector outlet with small flow and low pressure
oil injector outlet with high pressure Oil injector with serious vibration and increasing noise level obviously
Table 1 Reason Nozzle is blocked completely or the pressure oil (power oil) tube breaks up Strainer is blocked or the consumption oil in lube oil tube leak-off system is too high System with small oil capacity Oil level is lower or the strainer is loose and blocked
Solve method Check the tightness of nozzle and power oil pipe Clean strainer and check the lube oil pipe
Increasing the oil level and check the strainer
7. Cleanliness re-checks The oil injector shall be cleaned and rechecked before installing. The inner/external surface of oil injector shall conform to the requirement of clean-2 in JB/T4058-1999. The rust must be removed at once.
- 186 -
Suction inlet to main oil pump
I# oil injector
To oil cooler
II# oil injector
From main oil pump outlet
Attached drawing0-1-1
section5
Main oil pump description
1 General The main oil pump is the most important element in the turbine oil supply system of steam turbine. It supplies the whole turbine oil system with power oil source during the steam turbine at rated speed and the unit at normal operation. The main oil pump is located in the front bearing housing of steam turbine; it is rigid connection with the main shaft of steam turbine and driven directly by main shaft. The main oil pump is horizontal centrifugal pump with single stage and double suctions and the oil is supplied by pressure. The design parameters of main oil pump are as follows: speed
3000 r/min
flow
>3000 l/min
suction pressure
0.09~0.12 MPa
outlet pressure
1.85~2.05 MPa
wasted work
~200 kW
working medium
L-TSA32 turbine oil
medium temperature
45~65 ℃
2 .Structure description (see drawing 0-1-1) 2.1 Stationary section The stationary section of main oil pump consists of pump casing, end cover, sealing ring and floating bearing etc. The inlet and outlet interfaces of main oil pump are arranged in a line at lower part and integrate with base seat of it. A screw plug with bore is equipped at the top of various chamber of pump casing to exhaust the gas from each chambers during the unit start-up to ensure the stable operation of main oil pump and oil system. 2.2 Rotating section The rotating section of main oil pump consists of disc, pump shaft, sleeve and key etc. The dynamic balance test has been performed for the rotor of main oil pump after assembling in factory to ensure the stable operation of main oil pump. The pump shaft of main oil pump is connected with rigid connection with the main shaft of steam turbine by rigid coupling with male-female spigot for alignment The pump shaft is connected with main shaft by 12 M20 bolts. The tachometer gear board located on pump shaft is used for measuring the speed and expansion difference of steam turbine unit. The emergency tripping device is mounted at the front of pump shaft. 2.3 Sealing of main oil pump The floating sealing ring is used for main oil pump. The sealing ring can float in the pump casing freely. It is not only to allow the rotor of main oil pump moving axially but also to compensate the displacement of rotor at the vertical direction. ZCuSn5Pb5Zn5 is used for sealing ring.
2.4 Floating bearing and lubrication The floating bearing located on main oil pump is a round bearing. It is used for compensating the elevation variation caused by temperature difference between main shaft of steam turbine and main oil pump during the unit operating. The floating bearing is mounted at the left end cover. The sliding load used for fixing the bearing pedestal is adjusted by compression spring mounted on the end cover. The turbine oil is used for forced lubricating the bearing. One lube oil tube is lead out from lube oil main mounted in the front bearing housing to connect with the contact at the lube oil inlet mounted on the pump casing of main oil pump. 3. Requirement for assembly and installation 3.1The cleanliness of various components and inner/external of main oil pump must conform to the requirement clean-2 in JB/T4058-1999 Cleanliness standard of steam turbine before assembling and installing the main oil pump 3.2 The clearance value at various sealing of main oil pump must conform to the requirement on drawing. 3.3 The installing elevation of main oil pump must be adjusted according to the manual of main turbine to ensure the well alignment between the rotor of main oil pump and main shaft of steam turbine. 3.4 The installation type of pump shaft and steam turbine rotor shall be considered during installing the main oil pump to ensure the rotating/static clearance between rotor disc and pump casing of main oil pump conform to the requirement on drawing and prevent them from the rub between rotating and static parts during the unit operation. 3.5 The relative lube oil pipe must be connected well according to the requirement of system. 4. Operation and maintenance 4.1The main oil pump is put into operation while the steam turbine with speed 3000r/min. It is difficult to observe the operation state of main oil pump during operation. Therefore, we must be careful for installing and maintaining of main oil pump. 4.2 In case the inlet parameter of main oil pump conforms to the design requirement, the reason for the outlet oil pressure short of the design value must be analyzed. The main oil pump is required to check after confirming the piping system without leakage and with normal connection. 4.3 The main oil pump must be checked completely during the unit overhaul. The wear parts must be replaced and the main oil pump must be cleaned completely. 4.4 The small bores of 3 screw plug with bore located on pump casing must be smooth and without block, and various clearance requirement on drawing must be ensured during re-assembling.
Joint for lube il
rotor bi
of
steam
Emergency
Expansion difference check surface speed metering gear
Figure 0-1-1 ①rotor ②right end cover ③sealing ring ④pump shell⑤sealing ring ⑥sealing ring ⑦left end cover ⑧floating bearing ⑨pipe connection
section6 1.
Instruction for Spill Valve
General Description
Spill valve is used to adjust the pressure of mother pipe for lube supply, to ensure a stable pressure and flow of lube oil at bearings and to meet operational requirement of bearings, so that the entire lube system can supply sufficient and reliable oil, to achieve a safe operation of the generating system. Under the variable working conditions like startup and shutdown of unit, the spill valve has also the function for automatically adjusting the lube pressure, to minimize the impact on the system due to change in oil pressure. 1.1 Performance Data Maximum spill:
Qmax=500L/min
Maximum spill pressure:
Pmax=0.255MPa
Normal spill:
Qc=100L/min
Normal spill pressure:
Pc=0.196MPa
Minimum spill:
Qmin=0L/min
Minimum spill pressure:
Pmin=0.176MPa
1.2 Operating Principle The valve is fitted on the mother lube pipe behind the outlet of oil cooler. The opening degree of the spill valve (i.e. the spill quantity) depends on the balance position of such applied forces as pressure on the mother lube pipe, reaction of spring, and weight of slide valve, etc. When pressure on the mother lube pipe is less than or equal to 0.176MPa, the reaction forces of spring and so on will be larger than the opening force of slide valve which will then be in the lower position and the outlet of spill valve will not overflow as fully blocked. When pressure on the mother lube pipe is 0.196MPa, the slide valve will move upwards and spill outlet will appear partially. Now the oil overflows from the outlet and moves back to oil tank through lower part of the spill valve, to drain the oil and stabilize the pressure of mother pipe. 2.
Structure and Description This device consists of valve shell, valve cap, sleeve of slide valve, slide valve, spring, and mandril, etc. Refer to Figure 0-1-1. To keep slide valve from getting stuck and to improve the valve sensitivity, buffer chamber is composed of valve cap, sleeve of slide valve and slide valve to connect with lube oil in front of the spill valve through an eyelet on the slide valve, and the pressure oil before the valve enters the chamber through this eyelet. When any change in pressure before the valve takes place, the pressure in the chamber varies accordingly to eliminate the insensitive zone of spring and to improve the sensitivity of spill valve. At the same time, the lube oil into the chamber will play a lubricating and protective function for the slide valve, sleeve of slide valve, spring and other parts. This part of lube l will be drained back to the oil tank through the eyelet on valve cap.
3.
Installation, Assembly and Disassembly
The valve should be installed vertically and the interface before valve is connected with the mother lube pipe at the outlet of oil cooler. Relieved oil should be directly drained into oil tank or oil return pipe free from pressure. When valve is installed inside the oil tank, the interface behind the valve needn’t be connected with the pipeline, but oil drain tank directly instead. In the case when valve is fixed in other parts, a piece of pipeline is to be used to connect the outlet of the chamber on valve cap into the oil return pipe of the spill valve outlet. The disassembly sequence is: Firstly loosen the cap nuts and write down H value in the drawing. Then unlock the mandril and dismantle the valve cap to take out spring, and slide valve, etc. The valve sleeve and shell are assembled by tight fit and the sleeve is not to be taken out generally. The assembly sequence is contrary to that of disassembly. 4.
Maintenance
During installation and overhaul of the unit, the spill valve should be disassembled for inspection and cleaning to ensure a safe, reliable and normal operation of the unit. During re-assembly after inspection and cleaning, the slide valve can be manually pushed to check if it is free and flexible or not. In any jamming case, the slide valve is to be re-cleaned. When re-assembling the mandril, its position should meet requirement of H value which is to be further properly adjusted according to the pressure on the mother lube pipe when unit speed arrives at 3000rpm and all auxiliary oil pumps are out of service. Rise in H value will lead to an increase in oil overflow and decrease in pressure of mother lube pipe, and vice versa. Adjustment of valve is to ensure that the lube pressure before entering all bearings is 0.08~0.12MPa. It is worthwhile to emphasize that pressure of relieved oil in 1.1 is the design value before valve, with the consideration about pressure change arising from elevation. In actual operation, when lube pressure exceeds 0.255MPa, oil overflow of spill valve will be more than 500L/min. Only the maximum value selected for design is listed in 1.1. The spill valve shall be thoroughly cleaned after the oil circulation of new unit and overhauled unit.
5.
Refer to Table 0-1-1 for possible failures and solutions. Table 0-1-1 Failure
Fail to adjust pressure or no spill
Cause
Solution
z
Slide valve jammed
z
Check and clean to eliminate dirt
z
Throttling before or behind the buffer chamber
z
Open up the throttling eyelets
z
Hole blocked
z
Open up the hole
z
Spring damaged
z
Replace the spring
Cap Nut
Mandril
Valve Cap Oil Return Tank Buffer Chamber
Spring Oil Inlet
Slide Valve
Valve Shell
Oil Return Tank
Sleeve of Slide Valve
Figure 0-1-1 Spill Valve
Section7
Instruction for Twin-Tongue Check Valve
0-1 Instruction for Twin-Tongue Check Valve 6.
General description In oil system pipeline of steam turbine, to ensure that all auxiliary pumps are normally put into operation and cut off as well as a normal operation of the system, the pipeline is equipped with several different check valves to meet requirement for safe operation of the system. This twin-tongue check valve (Fig. 0-1) is used for oil supply pipe. Even when one of the valve discs is not tight, it can still ensure a normal work of the lube system and proper operation of the steam turbine.
7.
Structure and working principle
The check valve is composed of valve core, valve body, coupling flange and etc. The twin-tongue check valve consists of 2 valve cores (See Fig. 0-1). The valve cores of the check valve of the same diameter are interchangeable. Resistance at opening of the check valve is shown in table 0-1 Drawing No.
M522.X01Z
Content Pressure in front of the valve
Po
Valve disc sealing area ratio
0.877
Opening pressure
0.135Po
When pressure before valve is more than the sum of pressure behind valve and resistance at opening check valve, the check valve is automatically opened under the function of hydraulic pressure difference, and when pressure in front of the valve is less than pressure behind the valve, the check valve will be automatically closed. In order to avoid the check valve from being opened overwide and to ensure a tight close of the check valve, the measure for lengthening axis of valve disc is adopted for limiting the opening degree of the valve and the valve sealing surface is designed into a structure of 75° angle against the direction of fluid movement. 8.
Technical requirement for application
3.1 The structure description of the check valve is shown in table 0-2 Drawing No
M522.X01Z
Content Nominal diameter
125
3.2 Maximum opening of the check valve: 650 3.3 Working temperature of the check valve should not be more than 350℃
3.4 Working pressure of the check valve cannot be more than 2.5 MPa 3.5 The medium used by check valve is oil or other liquid without corrosion. 9.
Installation Requirements
4.1 The check valve is installed on respective pipelines with melding method. When check valve is arranged horizontally, the valve axis must be located on top. 4.2 Prior to installation, the check valve should be cleaned up, away from any deposit builder such as dirt, rust and other contaminants. The valve shall be disassembled and cleaned when necessary. 4.3 Pipelines connected with the check valve should be cleaned up before fitted in. If condition permits, the pipes should be phosphorized with pickling (or passivated). When installed into the oil system of steam turbine, the respective pipes shall comply with the Cleanliness-II requirements of JB4058-85. 4.4 Connections between the check valve and pipes should be argon-arc welded to ensure the quality of welds and piping cleanliness after welding. 4.5 After welding, welds between the check valve and pipes shall be cleaned up and coated with HU-20 turbine oil for rust protection. 10. Overhaul and maintenance 5.1 The check valve shall be repaired and maintained periodically along with overhaul of the unit. 5.2 It is only needed to twist off the bolts on the flange at both ends to dissemble the check valve. If piping interference occurs, pipes can be properly pulled apart with chain hoist to easily dismantle the check valve. 5.3 What is taken off the check valve is only a valve core, while another valve disc is still on the pipeline. At this time, the valve core can be pulled out by grasping its sealing face. 5.4 Mainly the sealing face between valve core and disc is checked for overhauling the check valve, and there should be no notch, nick and attachments. If the said exists, it is necessary to polish and face up to meet the sealing requirements. 5.5 When check valve gets stuck, mainly the clearance between valve arm and disc is to be adjusted and to ensure a smooth operation of the check valve by adding gasket into the said clearance. 5.6 During repair of the check valve, pressure test shall be performed as per technical requirements of related drawings. Refer to corresponding drawings for sealing requirements. 5.7 Pressure test of check valve can be conducted with corresponding valve body. 5.8 The sealing gasket between the flange faces shall be replaced when the check valve is re-assembled.
Figure 0-1
section8
Operating Instruction for Oil Smoke Separator
1.
Structure This device is composed of oil smoke separator, connecting tube, and smoke exhaust fan.
2.
Application This device is used to extract the oil smoke from the oil system, including bearing box, oil pipe and oil tank, to prevent from fire and pollution arising from smoke emission. At the same time, it can separate the oil drops from the smoke and let them flow back to the oil tank, to reduce the loss of turbine oil. Installation, Operation and Maintenance This oil smoke separator is vertically installed on the oil tank cover, one in use and the other standby. Inch the motor after closing the butterfly valve on the fan outlet to check if the fan rotates properly. Start the fan motor if everything is normal. Then slowly open the butterfly valve of the fan outlet, and adjust the negative pressure of the oil tank to 1 Kpa. This equipment should be cleaned and maintained regularly.
3.
Refer to the operating instruction provided with the device for detailed structure as well as operation of the fan and the oil smoke separator.
Smoke Exhaust Fan
Butterfly Valve
Connecting Tube
Oil Smoke Separator
Figure 0-1-1 Oil Smoke Separator
Chapter5 INSTRUCTION OF HYDROGEN、SEAL OIL、 STATOR COOLING WATER SYSTEM FOR 300MW GENERATOR section1
GENERAL
The auxiliary device of the QFSN-300 type steam turbine generator contains three parts: hydrogen control system, seal oil control system and stator winding cooling water control system. 1.1 The functions of the gas control system include: 1.1.1 Displacement the gas in the generator. 1.1.2 Maintaining gas pressure in the generator. 1.1.3 Monitoring the operation condition of the generator for gas pressure and purity and the presence of liquid in the generator at all times. 1.1.4 1.2
Drying the gas in the generator. The functions of the seal oil control system is:
1.2.1 Providing seal oil to a sealing continuously. 1.2.2 Prevent the escape of hydrogen gas from the generator. 1.3 The functions of the water control system include: 1.3.1 Ensure supplying water to stator winding continually. 1.3.2 Monitoring the operation condition of the generator for water pressure、 water flow and conductivity, containing and improving water quality.
section2
Hydrogen control system(See hydrogen control system diagram)
2.1 Main technical parameters: 2.1.1 Rated hydrogen pressure in the generator: Allowable maximum hydrogen pressure:
0.3MPa.g
0.35MPa.g
Hydrogen purity: ≥96% (a volume vat) Hydrogen humidity: 4g/cu.m (Under the condition of the rated hydrogen pressure 0.3MPa.g) 2.1.2 The filling hydrogen volume of the generator and the hydrogen piping system is 83cu.m. 2.1.3 Hydrogen leakage amount of the generator and the hydrogen piping system (except the hydrogen storage equipment on the supply hydrogen
station and the hydrogen bus duct): 5% of filling the hydrogen volume. 2.1.4 Volume and time for gas replacement is listed as follows Required Gas
carbon dioxide
Changeover
volume
operation Gas
required Gas
Air
of Estimated required time
180cu.m
5~6h
260cu.m
5~6h
(purity>85%) Hydrogen
Carbon dioxide
(purity>96%)
Hydrogen pressure is 210cu.m
1~1.5h
increased to 0.3MPa carbon dioxide
Hydrogen
150cu.m
4~5h
(purity>96%)
2.2
Operating principle of the hydrogen system: Hydrogen is inputted to gas control station from the hydrogen supply
system through double bus duct and is delivered to the generator after straining out solid impurities by a filter and removing moisture though a gas dryer。 Two sets of automatic hydrogen make up device will be provided on the gas control station, one is solenoid valve, when the hydrogen pressure in the generator is reduced to the lowest limit of a set value, the contact in the pressure controller is turned on and the solenoid valve is opened, The hydrogen enters the generator through the solenoid valve. When the hydrogen pressure in the generator increases to the highest limit of a set value, the contact in the pressure controller is turned off and the solenoid valve is closed and filling hydrogen is stopped. Another is a pressure reducer, it's the output pressure value is sets the rated hydrogen pressure value of the generator. Therefore, as long as the hydrogen pressure in the generator is reduced, hydrogen will occur at the output terminal of the pressure reducer until the hydrogen pressure in the generator is resumed to the rated value. A safety valve is installed on the gas control station. When the hydrogen pressure in the generator is excessively high, hydrogen pressure can be relieved.
Parts of hydrogen in the generator enter the hydrogen dryer along the pipeline under the action of the fan. The dried hydrogen returns to the suction zone of the fan in a continuous circulation so that the hydrogen moisture in the generator is reduced. Similarly, the hydrogen flowed in the hydrogen purity analyzer is also conducted by the action of the fan. The hydrogen purity in the generator can be continuously analyzed by the analyzer, and 4～20mA signals will be given out . Four oil/water monitors are furnished in the hydrogen control system. They separately are installed on the CO2 pipeline and the bottom of the generator. When oil or water enters the generator and over setting valve, the floats in proper will be rise and turned on electric enunciator circuit and alarm signals will be given out. When the generator and the gas pipe are required to be air tightness tested with compressed air, the compressed air is inputted into the generator through a valve on the gas control station after being dried by the gas dryer. After the air tightness test is qualified, the compressed air is drained to the outside of the power house. It is prohibited to directly filling hydrogen (or air) into the generator when the generator is filled with air (or hydrogen) so as to avoid the formation of explosive air-hydrogen mixture. Therefore, gas replacement must be conducted for the generator and hydrogen pipeline system. CO2 gas or N2 gas in a standard gas bottle may be fed into the generator from the generator bottom along piping after being reduced from the maximum pressure of 15MPa to 0.2~0.5MPa through the pressure reducer. Thus the replaced air (or hydrogen ) is drained to the outside of the power house along the hydrogen piping of the generator. 2.3 About the gas displacement of the generator 2.3.1 After the pipeline installation ( or maintenance ) for the generator, and the air-tightness test is qualified, gas replacement can be conducted, the way is that inert gas, such as CO2 or N2 can be used to drive out air (or hydrogen ) in
the generator and then the inert gas is driven out from the machine with
hydrogen, so as to prevent hydrogen and air from contacting directly during
gas replacement, therefore, no explosive hydrogen-air mixture can be formed, this process of gas replacement is called the intermediate medium replacement way. Prior to hydrogen charging, CO2 gas ( or N2 gas ) is used to drive out air from the generator, after CO2 gas content in the generator is over 85% ( N2 gas content over 95% ), and then CO2 gas ( or N2 gas ) shall be driven out by hydrogen, finally, then the generator is charged with hydrogen. During hydrogen discharging, CO2 gas ( or N2 gas ) is carried to the generator to drive out hydrogen, after CO2 gas content is over 95% ( N2 gas content
over
97% ), compressed
air
can be fed into the generator to
drive out CO2 gas ( or N2 gas ), after CO2 gas (or N2 gas ) content is lower than 15%, the compressed air introduced to the generator will be stop. 2.3.2.The following points shall be noticed during intermediate medium replacement. 2.3.2.1
Hydrogen, compressed air and intermediate gas (CO2 gas is
preferable )must be introduced to the special inlet on the gas control station and they cannot make a mistake. 2.3.2.2 Gas flow speed should be properly controlled to prevent producing a heat source in variable diameter of pipe due to excessively high gas flow speed. 2.3.2.3
A given gas pressure shall be stored during all process of gas
replacement in the generator (the pressure is between 0.01~0.03MPa ). 2.3.2.4 Fire is strictly prohibited near the site or the orifice of discharged pipes. 2.3.2.5
Correct and comprehensive sampling points are required, during the
process of gas replacement frequent discharging work shall be done for gas displacing pipe and dead zones where gas can not be easily circulated such as gas dryer, seal oil tank sample shall be taken from all these points, the test results shall be in accordance with the requirement. 2.4 2.4.1
Main equipment of hydrogen control system : Gas control unit and the carbon dioxide standard manifold bar are
designed on shape of closing to wall type. 2.4.2
Two refrigerating hydrogen dryer .
2.4.3
Hydrogen analyzer .
2.4.4 2.5
Gas dryer is adsorption type dryer . Points of attention for installation :
2.5.1 All pipes are all seamless steel tube, the inner wall of tube must be cleaned. 2.5.2 Sealed material of flanged coupling must use oil proof rubber plate thicker than 3mm. 2.5.3 The hydrogen-side pipe of the gas control unit must be done gas -tight test independently. Testing pressure is the same as that of hydrogen-storing equipment, usually 1MPa. The other equipment and gas pipe better to be done gas-tight test independently, testing pressure are about 0.6MPa, so shorten time of looking for leakage. 2.5.4
Drying agent in dryer must be rightly placed before gas-tight test.
2.5.5 All the gauges and instrument of this unit must be recalibrate before installation. 2.6
Regulating and test of hydrogen system. After installing, the hydrogen system should be regulated and tested on
the working field as follows. 2.6.1 Setting of safety valve There is a safety valve on the gas control unit. Its released pressure is adjusted by spring. The released pressure of safety valve of this unit is set to 0.36MPa. Setting will be doing on the unit’s pipe. Firstly, carrying into H2 gas or compressed air from the pipe bus valve of carbon dioxide standard manifold. when the gas pressure rises to 0.36MPa, by turn adjusting nut on the safety valve, the safety can open automatically and released pressure in pipe. When the pressure falls to 0.3MPa, close the safety valve. When pressure is 0.28MPa, you can check leakage by using soap water. The Safety valve must avoid leakage condition. 2.6.2
Setting of the pressure controller
The pressure controller is a switch that opens on circuit's pressure changing. You can open and close hydrogen makes up solenoid valve by it, at the same time it can indicate low pressure in the generator.
When regulating
pressure controller, carrying into compressed air, the pressure gauge indicate
0.28MPa, then release lock of pressure controller, turn setting button, make indicating needle point at pressure valve needed, that is point of 0.28MPa, at this time, switch should be closed, if electric return circuit is energized, the solenoid valve should be energized and open. Then raise pressure to 0.3MPa, the switch should be turned off. Electric return is switch off, the solenoid valve is closed. It should be calibrated twice at least. If there is no abnormal condition, then lock out after one more recalibration, if there is no abnormal condition, you can finish regulating work. 2.6.3 Installation and regulation of hydrogen analyzer and oil/water monitor refer to manual provided by its factory. 2.7 The operation and maintenance of the hydrogen unit. 2.7.1 The drying agent in dryer should be changed at regular interval. Especially for unit with high moisture lubricant, it should be changed frequently, drying agent should be changed at first time three months after it is put into operation. Therefore changing time depends on situation, but not more than four and a half month. 2.7.2
Instrument and gauge should be calibrate at regular interval, the
pressure controller and the safety valve also should be set at regular interval. It is recommend to set every 6 months.
Section3 3.1
Seal Oil control system(See the seal oil control system diagram)
General The turbine lubricating oil for generator seal ring is named seal oil
according its purpose. Seal oil system supplies oil to seal ring of the generator, and the pressure of oil greater than the pressure of hydrogen to prevent hydrogen in the generator leak out from the gap between seal ring and rotation shaft, at the same time prevent oil pressure too high to a lots oil enters the generator. Seal oil system is decided according the type of the seal ring. The double ring type seal oil system and the single ring type seal oil system are main types. This exposition is adequate for single ring type seal oil system designed and made by DFEM.
3.2 Main technical parameters: Seal oil: same as lubricating oil Inlet oil temperature of the rings: 25℃～50℃ Outlet oil temperature of the rings:≤70℃ Differential pressure between in the rings and hydrogen in generator: 0.056±0.02Mpa seal ring oil quantity: turbine side:92l/min; excitation side:92l/min. 3.3 Operating principle: Seal oil system includes the main circuits as following: regular operation circuit、emergency operation circuit、emergency seal oil circuit (the third seal oil source). 3.3.1 Regular operation circuit: Bearing lubricating oil pipe → vacuum tank →main seal oil
pump (or
pump for stand-by )→seal oil filter→differential pressure regulating value→ seal ring of the generator→hydrogen side drain (air side drain mixed with bearing lubricating oil drain flow to air detraining section directly)→ oil drain enlargement section →float trap→air detraining section→bearing lubricating drain→turbine main oil tank 3.3.2 Emergency operation circuit: Bearing lubricating oil pipe →emergency seal oil pump (D.C pump) → differential pressure regulating valve → seal oil filter → seal ring of the generator→hydrogen side drain
(air side drain mixed with bearing lubricating
oil drain flow to air detraining section directly)→seal oil drain enlargement section →float trap—→air detraining section→bearing lubricating drain→ turbine oil tank . 3.3.3 emergency seal oil circuit: (third oil source) This circuit is operated when both main seal oil pump and D.C pump were stopped , the bearing lubricating oil can be used as seal oil for sealing the hydrogen ,at this time the hydrogen pressure must be decreased to
0.05MPa~0.02MPa. 3.4
Main equipment of seal oil control system:
3.4.1 seal oil drain enlargement section The hydrogen side drain pipe of the turbine side and the excitation side connect to drain enlargement section, in which the drain oil can be spread out and eliminated hydrogen. 3.4.2 float trap The drain oil of hydrogen side pass by enlargement section then enters float trap, which purpose is eliminate the hydrogen in oil any more. 3.4.3 Air detraining section Air side drain mixed with bearing lubricating oil drain flow to air detraining section, gas in oil is drained to outside of building through pipe, lubricating oil flow back to turbine main oil tank
.
3.4.4 seal oil supply station It consist of the following main equipments assembled on a base plate: two main AC pumps, one emergency seal oil pump, vacuum device, one differential pressure regulating valve, some instruments and valves. 3.4.4.1 Vacuum device The vacuum tank, vacuum pump and recirculating pump are the main equipments of vacuum device. they are oil purifying equipments of the seal oil system for single-ring type. 3.4.4.1.1
Vacuum tank(refer to 3.4.5)
3.4.4.1.2
Vacuum pump works continually to keep high vacuum in the
vacuum tank, the air,and moisture in oil can be drained out at the same time. 3.4.4.1.3
Recirculating pump works continually, so the oil in vacuum tank
come into a repeating local circulation through pipe, and it can be clean much more. 3.4.4.2 Oil pump There are two main seal oil pump ,one for regular and one for stand-by .They are both driven by A.C motor ,so they are named A.C oil pump. One emergency seal oil pump will start up when main oil pumps are
stopped in trouble .It is driven by D.C motor, so it is named D.C oil pump. 3.4.4.3 Differential pressure regulating valve The regulating valve regulates oil pressure which enters seal ring automatically, and it follows the change of the gas pressure in generator automatically in order that the differential pressure between oil and hydrogen should be maintained at needful range. 3.4.4.4 Seal oil filter Seal oil filter is fitted the outlet pipes of the differential regulating valve, it is used for filtering solid impurity in the seal oil. 3.4.5 Vacuum tank When A.C seal oil pump is works normally, bearing lubricating oil enters vacuum tank on and on, gas and moisture is separated from oil in vacuum tank, and drained out through vacuum pump and pipe , therefore the oil which enter seal ring can be cleaned and also air or moisture can be prevented to pollute hydrogen in the generator. There is a float valve in vacuum tank. its float ball rise or down following oil level high or low to regulate the valves open-close angle, thus it can control the speed for makeup oil
and
oil level.
Liquid level annunciator is a main adjunct too. oil level will be seen through it and it will send alarm signal when oil level high or low. 3.5
Regulating and setting of seal oil system
3.5.1 The setting of the pressure controller When the outlet oil pressure of oil pump is low to 0.54Mpa,the pressure controller(PCL-201) delay 3~5 seconds to start standby oil pump. If PCL-201 turn off in low pressure condition and A.C standby pump cannot maintain normal work pressure,then D.C pump control circuit be passed,D.C pump will start. 3.5.2 The setting of vacuum tank’s vacuum degree: PSH-202 is a pressure switch. For high purity of hydrogen, gas in seal oil must be reduced to the lowest limit. The lowest limit setting value of the vacuum degree is –88Kpa.g, when vacuum degree exceed the value, it gives out alarm. 3.5.3 Reducer (S-18) When running normally, the pressure of filter inlet pipeline maintain 0.65~0.7Mpa. S-18 should be set according the value. 3.5.4 the setting of vacuum tank liquid level annunciator’s position The middle position of the liquid level annunciator is set as the normal oil level
position. Being up or down 100mm from the normal oil level position, it will give out a signal. 3.5.5 The setting of low limit value of differential pressure regulating valve The oil-gas differential pressure standard value is 0.056Mpa, which decrease to 0.036Mpa as the low limit alarm signal. 3.6
Daily monitor item
3.6.1 the value of oil-gas differential pressure in generator; 3.6.2 the oil level in vacuum tank and float trap; 3.6.3 whether there is oil in liquid level annunciator(LS-201 ); 3.6.4 seal oil vacuum pump run condition 3.6.5 all instrumental display value 3.6.6
seal oil pump outlet pressure
section4 Stator winding cooling water system(see stator winding cooling water control system diagram) 4.1 Main technical parameters: 4.1.1 Stator winding cooling Water: Water pressure at the inlet:
0.1~0.2MPa
Water temperature at the inlet: 45±3℃ Return water temperature: ≤85℃ Total water flow: 45t/h Water quality requirements: Conductivity: 0.5~1.5μs/cm(20℃) PH value: 7-8 Hardness:
2 microgram equivalent litter
4.1.2 Whole volume of
the
system
4.1.3 Circulating water flow required:
3cu.m ~160t/h
Circulating water pressure required:
0.35MPa
4.2 Operating principle of cooling water system Stator winding cooling water system is an independent closed circulating circuit. Water from the tank is pumped and is introduced to exchanger to cool after rising pressure, solid impurity is removed through filter and cooling water flows into the stator winding of the generator. The return water flows back to
the tank by way of circulation. Some auxiliary devices are installed in the system, such as demineralizer, heat exchanger, some gauges are supplied to monitor water temperature, water pressure, conductivity and flow. By-pass pipeline and valve is installed on the stator winding inlet and outlet of the generator so as to wash stator winding in an opposite direction. 4.3 Main equipment of stator cooling water control system, all of the following equipment are assembled on a base plate : 4.3.1 Water tank, it is made from stainless steel. The tank volume is about 1.78 cubic meters. Max. filling water volume of the tank is about 1.6 cubic meters (from horizontal plane to overflow pipe), filling water device and liquid level annunciation is installed on the tank. When water level falls, the contacts
in
the annunciation turn on. Solenoid valve is opened by electric control circuit and cooling water flows into the tank. When water level is high, cooling water should be drained through overflow pipe. 4.3.2 Water pump. Two same type water pumps are furnished in the system, one operating, other for standby. When pressure of pump outlet is less than setting value, the contacts of the pressure control circuit turn on, standby pump is started by electric control circuit. 4.3.3 Water exchanger. The shell of exchanger is made from stainless steel. two heat exchangers are supplied in the system, one for operation, the other for standby. 4.3.4 Water filter. The shell of filter is made from stainless steel. Strainer is made from stainless steel screen. Two filters are installed in the system, one for operating and the other for standby. 4.3.5 Demineralizer. After the system is operated for period of time, cooling water quality will fall gradually, special demineralizer is supplied to improve water quality, it is not allowed to improve hard water directly. Mixed bed type demineralizer is adopted in the system. The cation and anion resin in demineralizer is the ratio of two to one, cooling water flow through the demineralizer is about 5t/h, and is 8% of total flow in the system. Regeneration of resin should be made by the outside of the demineralizer. According to
source of goods, resin type is determined by user. General, filling is about 160 litre. 4.3.6 Conductivity meter. Two same type conductivity meters are supplied the system, one is used to monitor conductivity of cooling water of the generator stator winding inlet. Other to monitor counter conductivity of cooling water of demineralizer outlet so as to determine if resin is need regenerated. 4.3.7 Temperature regulating valve. It is installed on the inlet circulation water pipe of water cooler, it controls circulating water flow so as to control outlet temperature of cooler. 4.4 Points of attention for installation. 4.4.1 Inner wall of pipe must be cleaned. 4.4.2 pipes and equipment of these units must be washed. It must be flanged connected with water supplying control station without impurity. 4.4.3 After system is connected with generator, It should be rinsed
reversely
first, Then has the reverse and forward rinsed alternatively. Water feeding pressures is no more than 0.25MPa. 4.4.4 Circulation water side of water cooler should have water pressure testing of 0.8MPa，30min. In testing, butterfly valve at inlet and outlet of temperature regulator should be closed. 4.4.5 Water pump's overhaul and maintenance can refer to manual provided manufacturer. 4.4.6 All instruments and gauges should be tested regulating in installation. 4.5 Regulating and setting. 4.5.1 Setting of protection value for cutting water. Flow protection return circuit. Stator winding water flow decrease to minimum value, and it cannot rise again in 30 seconds, the protection equipment of generator will be operated. Generator should unload and throw off load, normally the minimum setting value is 37~35t/h. 4.5.2 Regulation and testing of temperature regulator under the load condition according to manual, making feeding water temperature remain at 45±3℃. 4.6 Operation and maintenance of stator winding cooling water system.
4.6.1 According manual provide by manufacture under rated hydrogen pressure. hydrogen pressure in generator should be about 0.1~0.2MPa higher than feeding water pressure of stator winding cool water. When feeding water's pressure is 0.2MPa but flow is stilling sufficient, feeding water's pressure can be raised to 0.23MPa in order to increase flow, but when hydrogen pressure decreased to 0.26MPa. Hydrogen must be compensated. In a word, Hydrogen pressure in generator must be higher than 0.03MPa, darning water's temperature is not higher than 80℃. 4.6.2 When system is feed with water, pump cannot be started to open until overflow pipe start to over flow water pressure should be raised to presetting valve gradually. In this period, if water lever is too lower, operator should compensate water manually. In the meantime, you should open W-52、W-64 valve to drain gas till water flow, then close these valves. 4.6.3 When starting this unit in cold state, operator should heat cooling
water
to make its temperature higher 5℃ than hydrogen temperature by using electric heating equipment. Before operation you must first open W-50、W-51 valve, close W-57、W-56、W-58 valve, turn on electric heating so as to heater and water control station forming circuit. Operator should monitor gauge when water will be heating over H2 temperature 5℃ then cut off the heater power. Heater may installation near W-52、W-51 valve, so as to operation. 4.6.4 Sample gas from sampling valve on top of water tank is found its hydrogen higher than standard content after analyzing gas, operator should stop generator and check, putting stress on checking coil introduction water pipe. Normal operation sample valve should be closed. 4.6.5 When water cooler is supplying water circulately. Gas should be drained from water cooler's top. 4.6.6 Water feeding pressure of demineralizer should be limited under 0.35MPa. When water draining conductivity is higher than 0.5 μ s resin regeneration should be considered. 4.6.7 All of instrument and meters should be calibrated regularity.
Chapter6
DESCRIPTION OF CIRCULATING WATER SYSTEM Section1
1.1
General situation
2×300MW coal fired power plant is located in the north of Cilacap, Central
Java, Indonesia and adjacent on the INDIAN OCEAN. 1.2 meteorological condition 1.2.1 Atmospheric pressure（mbar） Average barometric pressure： 1.2.2
1008.2
Temperature（℃） Maximum monthly average ambient temperature：32.7 Minimum monthly average ambient temperature：20.9
1.2.3
Maximum extremely temperature：
34.5
Minimum extremely temperature：
17.4
Air relative humidity（％） Maximum monthly relative humidity：
93
Minimum monthly relative humidity： 1.2.4
Rainfall（mm） Maximum recorded rainfall for 12 hrs： Maximum recorded rainfall for 24 hrs：
73 77 230
Design rainfall intensity：70mm per hour for a 60-minute storm on a 15-year frequency 1.2.5
Wind speed Maximum design wind speed at 10m：120km/h Direction of prevailing wind：from SE to NW for 80% of year
1.2.6 1.3
Earthquake intensity：
0.3g
Ocean hydrologic data
1.3.1 Tide level 99% tidal water level 97% tidal water level 10% tidal water level 1% tidal water level
0.37m 0.48m 1.99m 2.46m
0.1% tidal water level
2.67m
100 years return period highest tidal water level 33 years return period lowest tidal water level
2.973m -0.077m
Wave： Deep-water wave for Cilacap Sea (50 years return period) Extreme value
Cumulative frequency
Wave height (m)
Wave period (s)
H13%=Hs
4.86
10.58
H1%=1.51Hs
7.37
13.7
H4%=1.28Hs
6.20
12.03
H5%=1.22Hs
5.93
11.75
1.3.3Water temperature design average seawater temperature: 26℃ design maximum seawater temperature: 34℃ 4) suspend sediment Year-to-year highest suspend sediment content：No information Year-to-year average suspend sediment content：No information
Section2
Design description of circulating water system
The once through cooling water system is adopted in this project and 2 sets circulating water pumps are installed for each 300MW unit. One circulating water pump house is common for 2 units. Two main circulating water pipes for two units are not connected with each other. 2.1
Main parameters of circulating water system
¾ Cooling surface of condenser：
17750 m2
¾ Cooling water pipe of condenser：
Ti, ф25×0.5
¾ C.W. Flow：
41050 m3/h
¾ C.W. inlet temp.：
26 ℃
¾ C.W. outlet temp.：
34℃
¾ Back pressure：
0.0067MPa
¾ Water velocity：
2.3m/s
¾ When C.W. inlet temp. is 34 ℃, Back pressure is 0.0118MPa ¾ Hydraulic loss and calculation of C.W. system at 100% flow 1) From water Intake to inlet chamber：
1.508 m
2) From C.W. pump to condenser inlet：
3.492 m
3) Condenser：
6.0 m
4) From condenser outlet to siphon well inlet：
3.754 m
5) Total head loss：
14.754 m
6) Static head from siphon well to mean water level: 7) Total head required:
2.879m 17.633 m
¾ circulating water flow for 2 units circulating water flow list (2X300MW) Table 2-1 circulating water flow NO. 1 2
Item of water demand Cooling water for condeser Cooling water for auxiliary heat exchanger Total
1×300MW 2×300MW 41050
82100
3300
6600
44350
88700
Remark
¾ Circulating water pump is vertical style mixed-flow type, model number is 72LKXA－17.9,the rated capacity is 6.26m3/s, total head is 0.179Mpa.The power of the match motor for circulating water pump is 1600KW and voltage is 6000V. 2.2
The structures and buildings of circulating water system The once through cooling water system is adopted in this project. The seawater
flow by gravity from water intake dock basin to C.W. pump inlet chamber through the C.W. intake open channel and be pumped to condenser and auxiliary heat exchanger through C.W. inlet FRP pipe by C.W. pump. After heat exchanged in condenser and auxiliary heat exchanger, the outlet hot seawater flow to siphon well through C.W. outlet FRP pipe and under drain, at last the hot seawater flow by gravity from siphon
well to sea through C.W. outlet open channel. 2.2.1
Structure of water intake
1) Water intake adopt bank side dock basin type according to the result of the 《WATER INTAKE REPORT》and water intake structure consist of breakwater, dock basin, intake open channel and bar screen. 2) Bar screen is installed at the end of intake open channel, the distance between the bars is 200mm.Water velocity across the bars is about 0.2m/s at design flow. 3) The detail design and arrangement of structure of water intake reference to the drawings and description provided by PT.Zhenhua Indonesia. 2.2.2 Water inlet chamber 1) Water inlet chamber is outdoor rectangular type and union with C.W. pump house. The dimension of inlet chamber is 24m×21m×12.3m. 2) The top platform elevation is +3.7m. 3) The water inlet chamber is divided into four independent parts for 4 sets circulating water pump, in each part, 1 set cleaning trash device, 1 set travelling band screen are installed. Distance between bars of cleaning trash device is 50mm and the mesh size of traveling band screen is 6mmX6mm. 4) For the purpose to cut off the water flow when cleaning trash device, travelling band screen and C.W. pump maintenance, 2 sets steel gate are installed upstream of cleaning trash device common for four independent parts of inlet chamber. 1set guiding groove for steel gate is installed in each part of inlet chamber. The start and stop of the steel gate is static water type. 5) There is 1 set cleaning trash device in each part of inlet chamber, and 1 set mobile trash rake is installed common for 4 sets cleaning trash devices. 6) 4 sets wash pumps, pipeworks and nozzles are provided for 4 sets travelling band screen back washing. the back washing pump specification is as following: EHG125-80-200 type ，Q=150m3/h H=0.46MPa N=37KW. 7) Two cooling water pumps for C.W.pump mating motor are installed at the platform of inlet chamber. The pump is deep well pump and its specification is as following: 12RJLC/4 type, Q=125~160~200m3/h H=0.39~0.345~0.285MPa N=30KW 2.2.3 Circulating water pump house
2sets C.W. pumps are installed for each 300MW unit in this project and one C.W. pump house is common for 2 units. The C.W. pump house is located at opposite side of the road which west of the turbine house. 4 sets 72LKXA-17.9 type C.W. Pump (Q=6.26m3/s, H=0.179MPa、n=425r/min, mating motor is YKSL1600-14/1730-1 type, N=1600kW, V=6000V,IP54) and 2 sets HFY65-12.5 type drainage sump pump (Q=25m3/h, H=0.125Mpa,N=3kW) are installed in C.W. pump house. The start and stop of C.W. pump can control at central control building and on site. Hydraulic
control
butterfly
valve
(D741aX-6
type,
DN1800,
PN=0.60Mpa,N=4kW,V=380V) is installed at the outlet of C.W. pump and can be closed automatically with quickly and slowly two closing stages. The closing time can be determined by the shakedown test. One electric double beam bridge crane (with cabinet) installed in C.W. pump house for equipment maintenance. The operation platform of the C.W. pump house has the control device room and maintenance area. The operation platform elevation is +3.70m. 2.2.4 Circulating water pipe The main circulating water inlet and outlet pipes nominal diameter is DN2200 and pipes are all fiberglass reinforced plastic pipe (FRP). The flow through circulating water pipe is 12.51m3/s and flow velocity is about 3.294m/s. For the purpose to enter into the pipe inside when pipe installation and maintenance, 2 manholes will be arranged at each main DN2200 pipe (near the C.W. pump house and turbine house). 2.2.5 Circulating water outlet under drain The circulating water flow out of the condenser and auxiliary heat exchanger of 2 units through the under drain enter into siphon well. The dimension of the R.C. under drain is 2X2000mmX2500mm .the flow is 25.03m3/s and flow velocity is about 2.503m/s. 2.2.6 Siphon well Siphon well is reinforced concrete construction and located at southwest of the power plant. The dimension of siphon well is 12400mmX20000mmX8500mm.The top platform elevation is +7.00m and the elevation of the top of weir in the siphon well is +3.00m. 2.2.7 Circulating water outlet open channel The circulating water flows out of the siphon well through the open channel enter into the sea by gravity. The bottom width of the open channel is 4500mm and
bottom slope is 0.002.The flow is 25.03m3/s and flow velocity is about 3.01m/s. 2.2.8 Cooling water for auxiliary heat exchanger There is 3300m3/h circulating cooling water flow from main circulating water pipe to auxiliary heat exchanger for each unit. The inlet and outlet Cooling water pipes for auxiliary heat exchanger nominal diameter is DN700 and are all FRP pipes. The water discharge from the auxiliary heat exchanger enter into circulating water outlet pipe and then flow to siphon well and enter into the sea through circulating water outlet open channel at last.
Section3
The construction and installation description of the circulating water system
3.1 The construction and installation dimensions in this project shall be according to the data which written on the drawings and forbid using the data which is measured in scale on the drawings. 3.2 The construction and installation shall be according to the requirements of the drawings. Drawings and relative descriptions shall be understood before construction and installation. If the drawing’s content isn’t clear or has other questions, please consult with site designer in time. 3.3 Embedded parts, embedded pipes and reserved holes in drawings shall be constructed simultaneously with the construction of the structure. After checking up the dimensions of arrival equipment and finding without mistake, the embedded parts will be constructed. Allowable dimensions deviation of embedded parts shall be not exceeded ±10mm except for that noted specially in drawings. Installation organization shall examine and cooperate at all hours in the process of structure construction. 3.4 The installation management plan shall be done ,the construction order of underground pipes shall be prepared at fist time, the lower pipes or foundations will be constructed at first and upper pipes later. 3.5 For the requirement of installation for circulating water pipe, please see the specification, which provided sub supplier by LIANYUNGANG LIANZHONG FRP CO.LTD. 3.6 The heavy-duty equipments shall be transported through the reinforce area of circulating water pipe after circulating water pipe backfilling, and the temporary pillow shall be beded on the pipe reinforce area to protect the circulating water pipe from crushing. 3.7 The shakedown test, installation and maintenance of all equipments in the circulating water system shall be performed according to the requirements of manufacturers. 3.8 Expansion joints for C.W. pump and hydraulic control butterfly valve are only use for adjusting the clearance between pipes when valve or pump installation and disassembly. After valve or pump installed, it must lock the lock bolt in joint to make the pipe and joint as a rigid body.
section4
Operating management description of circulating water system
4.1 C.W. pump 4.1.1 There are 4 sets C.W. pumps for 2 units in the C.W. pump house. And 2 sets C.W. pumps provide cooling water for one 300MW unit jointly at normal operation. When only one set C.W. pump provides cooling water for one unit at certain case, the other C.W. pump for the same unit is standby and interlock with the operation pump. And when the operation pump stop by accident, the interlocked pump shall start up automatically. 4.1.2 The C.W. pump and its outlet hydraulic control butterfly valve can be started up or stopped at central control room or at site by manual control. The operation position of C.W. pumps and hydraulic control butterfly valves can be displayed at C.W. pump house control device room and central control room. 4.1.3 The C.W. pump interlock with its outlet hydraulic control butterfly valve and cooling water pump for C.W. pump mating motor. The interlocked operation program is as following (for example with C.W. pump which code is 10PAC11APOO1,reference to drawing “circulating water pump house system flow diagram” and drawing NO. is 50-F209S-S0203A-01): 4.1.3.1 Normal operation The C.W. pump can be started up or stopped independently by manual control and started up or stopped interlocked with outlet valve at central control room. In addition, the C.W. pump and its outlet valve can be started up or stopped at site by manual control. （1）startup program of C.W. pump at normal operation: After push the interlocked startup button of C.W. pump, the program automatically confirm the C.W. pump outlet hydraulic control butterfly valve (10PAB11AA001) is closed and simultaneously judge the cooling water pump (00PAD11AP001 or 00PAD12AP002) for C.W. pump mating motor if startup. If the cooling water pump is already startup then open the motorized valve (10PAD11AA001), otherwise the program will start up the cooling water pump and open the motorized valve. If above process complete, program will open the C.W. pump outlet valve after 60 second (adjustable, 5 min for the fist time to operate), when the open angle reach 15 degree the program will start up the C.W. pump. Above process is interlocked at normal operation. （2）stop program of C.W. pump at normal operation: After push the interlocked stop button of C.W. pump, program will close the C.W. pump outlet valve and stop the C.W. pump motor after the valve closed angle reach 20 degree. 60 second (adjustable) later, the program will close the motorized valve of cooling water pipe for C.W. pump mating motor (only when 4 sets C.W. pump stop together, the cooling water pump shall be stopped interlocked). The outlet valve can be closed automatically
with quickly and slowly two closing stages: the fist is quickly closing stage, closing time is about 2.5~20 second (adjustable) and closing angle is about 70°±8°(adjustable); the second is slowly closing stage, closing time is about 6~60 second (adjustable) and closing angle is about 20°±8°(adjustable); Above process is interlocked at normal operation. （3）It shall be according to the order demanded at above description when above devices independently operate . Adjusting the order is not allowed. 4.1.3.2 The processing when accident (for example with C.W. pump which code is 10PAC11APOO1) （1）If operating personnel receive the alarm signal (such as motor bearing lube oil temperature, electric current value, flow alarm switch signal of cooling water inlet pipe for C.W. pump mating motor and so on) of C.W. pump and mating motor(10PAC11APOO1) or hydraulic control butterfly valve(10PAB11AA001),he shall make sure quickly what happened and stop the C.W. pump by manual control after confirmed by the administration of power plant. It’s stop program is as same as stop program at normal operation. （2）When C.W. pump (10PAC11APOO1)is stop by accident, it will send the alarm signal to central control room and interlocked close the outlet hydraulic control butterfly valve(10PAB11AA001) simultaneously. The outlet valve will close automatically with quickly and slowly two closing stages according to the adjusted closing angle and time. 60 second (adjustable) later after C.W. pump is stopped, it will interlocked close the motorized valve (10PAD11AA001) of cooling water pipe for C.W. pump mating motor. （3）When hydraulic control butterfly valve(10PAB11AA001) automatically close by accident, the alarm signal will be sent to central control room and interlocked close the C.W. pump (10PAC11APOO1)，60 second (adjustable) later after C.W. pump is stopped , it will interlocked close the motorized valve (10PAD11AA001) of cooling water pipe for C.W. pump mating motor. （4）If hydraulic control butterfly valve(10PAB11AA001) can not open completely by accident after C.W. pump start up 45 second, the alarm signal will be sent to central
control
room
and
interlocked
close
the
C.W.
pump
(10PAC11APOO1)，60 second (adjustable) later after C.W. pump is stopped , it will interlocked close the motorized valve (10PAD11AA001) of cooling water pipe for C.W. pump mating motor.
4.1.3.3 For the purpose to reduce the pump stop water hammer pressure, the hydraulic control butterfly valve (10PAB11AA001) closing time of two closing stages shall be determined by the shakedown test. The requirement of the shakedown test shall be reference to the relative specification, which provided by manufacturers of C.W. pump and hydraulic control butterfly valve. 4.1.3.4 When the circulating water pipe is empty or the prime operation, the suggestion opening extent of hydraulic control butterfly valve is about 1/3 of the totally opening and it shall fill the water into the circulating water pipe slowly. After confirmed that all pipes fully fill with the water, it can completely open the valve. 4.1.3.5 There are pressure meters at the outlet of all C.W. pumps, the design operation pressure is about 0.179MPa. 4.2 Cleaning trash device (with mobile trash rake) The control of the cleaning trash device (with mobile trash rake) is according to the water level difference between upstream and downstream of cleaning trash device. For example with cleaning trash device which code is 10PAA21ATOO1,the operation program of cleaning trash device is as following: (1) Program will inspect the water levels of upstream and downstream of cleaning trash device, when the water level difference reach to 0.3m(adjustable), the mobile trash rake will automatically start up, until the water head reduce to 0.1m(adjustable) it will stop automatically. The operation time shall be not less than 30min at each time. (2) Mobile trash rake will start up automatically at intervals of 24 hours (adjustable) for the purpose to prevent the revolving parts from being got stuck. In this process the mobile trash rake shall clean cleaning trash device one by one of each inlet chamber.
The operation time shall be not less
than 30min at each time. (3) Cleaning trash device (with mobile trash rake) can be started up and stopped by manual control at site.
4.2 Travelling band screen The control of the travelling band screen is according to the water level difference between upstream and downstream of travelling band screen. For example with travelling band screen which code is 10PAA31ATOO1,the operation program of travelling band screen is as following:
（1） Program will inspect the water levels of upstream and downstream of
travelling band screen, when the water level difference reach to 0.3m(adjustable), the travelling band screen will start up automatically, until the water head reduce to 0.1m(adjustable) it will stop automatically. The operation time shall be not less than 30min at each time.
（2） Travelling band screen will automatically start up at intervals of 24 hours (adjustable) for the purpose to prevent the revolving parts from being got stuck. The operation time shall be not less than 30min at each time. （3）avelling band screen can be started up and stopped by manual control at site.
4.3 Travelling band screen back wash pump The start up and stop of the travelling band screen back wash pump shall be interlocked with the travelling band screen. When travelling band screen start up, the program will start up the back wash pump too; when travelling band screen stop, the program will stop the back wash pump too. There are 4 sets back wash pump for 4 sets travelling band screen. One back wash pump is working for one travelling band screen. When the operation back wash pump is accident, the program will send the alarm signal to control room and display the code of the accident pump.
4.4 Y type filter on the outlet of travelling band screen back wash pump The differential pressure switch is installed between the inlet and outlet of the Y type filter. When the pressure differential reach to 0.05MPa(adjustable), the switch will send the alarm signal to C.W. pump house control device room and central control room to remind the operating personnel to wash the filter at site. The differential pressure can be displayed at control device room.
4.5 Cooling water pump for C.W. pump mating motor 4.6.1 there are 2 sets cooling water pumps for C.W. pump mating motor and interlocked with each other. When the operation pump is stop by accident, the interlocked pump shall start up automatically and at the same time the program will send the alarm signal to control room and display the code of the accident pump. 4.6.2 1 set cooling water pump provides cooling water for 4 sets C.W. pump mating
motors (the other stand by). The start up and stop of the cooling water pump is interlocked with the C.W. pump (see section 4.1). 4.6.3 Cooling water pump can be started up and stopped by manual control at site or at central control room. The operation position of cooling water pump can be displayed at C.W. pump house control device room and central control room. 4.7 Drainage sump pump 2 sets drainage sump pumps are installed at drainage sump in the valve pit of C.W. pump house. There are 2 sets drainage sump pumps interlocked with each other. 2 sets pumps are controlled by the water level of drainage sump. When the water level is 1.30m, a drainage sump pump will start up automatically and until the water level reduce to 0.70m the pump will stop automatically. When a drainage sump pump is already operating but the water level still rise to 1.80m，then the other stand by pump will start up automatically and at the same time it will send alarm signal to control room. When the operating personnel receive this signal he shall inspect and treat the problem immediately at site. When the operating pump is accident, the stand by pump will start up automatically and at the same time it will send alarm signal to control room. The operating personnel shall repair the accident pump soon. The water level signal of drainage sump and operating position signal can be displayed at site. 4.8 The water level of inlet chamber The water level of inlet chamber at downstream of travelling band screen shall be continuously displayed at site and central control room. When the water level under 7.0m(from the chamber bottom), an alarm signal will be sent to central control room for the purpose to remind the operating personnel that the water level is under the design lowest water level. The operating personnel shall take appropriate action after receive this low water level alarm signal. 4.9 The maintenance and checking of devices in circulating water system There is maintenance area in C.W. pump house. The maintenance of C.W. pump shall be performed in maintenance area. The hand oil pump is used for changing the lubricating oil of C.W. pump mating motor. The hand oil pump can be put in the maintenance area. The steel gate shall be needed to cut off the flow when the inlet chamber maintenance. The cut-off and start-up of steel gate is adopted static water type. When cutting off the flow of the inlet chamber, it shall stop all the pumps which suck water
in this inlet chamber first and then put steel gate in the chamber to cut off the flow, at last empty all water of inlet chamber by mobile discharge pump. After the chamber maintenance complete, pump water fill with this chamber from near by chamber by using mobile pump and still the water level upstream steel gate is as same as downstream steel gate, the steel gate can be lifted. The steel gate shall put in the maintenance area of inlet chamber（the robber water seal belt of steel gate shall be not pressed when putting）and mobile discharge pump can be put in the maintenance area of C.W. pump house. The mobile discharge pump shall be used to remove sand in the inlet chamber too. The devices of inlet chamber shall be lift to the maintenance area near by the inlet chamber by truck crane
to check.
Before and after plant operating, it shall clean up the settling sand in intake dock basin and intake open channel by dredger to prevent the large quantity sand from entering into circulating water system; it shall clean up the marine life that adhere to the surface of devices and inside surface of circulating water pipes in the period of the unit maintenance 4.10 Notices （1） Operating personnel shall pay attention to the water level of inlet chamber. It shall guarantee the submersed water depth of C.W. pump to prevent the air from entering into inlet of C.W. pump. （2） To avoid air accumulation at the top of cooling water pipes of condenser (or at top of condenser water chamber), it shall open the vent cock and vent valve before the condenser operating, and then fill the cooling water pipes and water chamber with water slowly. After doing this it can close the vent cock and vent valve. （3） It shall start up or stop C.W. pumps one by one with intervals more than 10min. （4）
The appropriate closing stroke and closing time of C.W. pump outlet hydraulic
control butterfly valve are very important to reduce the pressure of water hammer and avoid the C.W. pump rotating inverted. The closing time and closing stroke shall be determined by shakedown test before the circulating water system operating.
