Frames5&6GTOperation&Maintenance
GTBASIC WORKING PRINCIPLE (BRAYTON CYCLE)
2
GASTURBINETHEBASICWORKINGPRINCIPLE (BRAYTONCYCLE)
3
GAS TURBINES CLASSIFICATIONS |
Application y Fixedspeed electricalpowergeneration y Variablespeed mechanicaldrives,pumps,compressors
|
Design y Industrial,heavyduty,robustlonglife y Aircraftderivative,lightweight,deratedforstationary applications
|
Rotor y Singleshaft(usuallygeneratorapplications) y Dualshaft(usuallymechanicaldrives) y Threeshaft(aeroderivativetypes)
|
Cycle y Simplecycle y Regenerative y Combinedcycle
4
SEQUENCEOFOPERATION AIR FUEL EXHAUST
EXHAUST
FUEL
AIR
5
HEAVY DUTY ONE SHAFT GAS TURBINE B.V FS5001 W251 V63
EGT (T3)
EGT (T4)
Starter Motor
IGV CDP
T1
NHP
=
NPT
6
GT F5 Single Shaft
7
TWO SHAFT INDUSTRIAL GT WITH 2ND STAGE NOZZLES
6 Combustor Inlet
1
2
5 3
Compressor
4
Turbine
net Power output Turbine work
8
CLASSIFICATIONS OF GAS TURBINE BASED ON THE MANUFACTURER General Electric (GE) (Nouvo Pignone) Frame 5 15-25 MW Frame 6 33-45 MW Frame 7 50-150 MW Frame 9 100-250 MW Westinghouse Model 251 35-50 MW Model 501 100-150 MW Model 701 100 -150 MW (50 Hz) ABB Model GT8 47 MW Model GT13E 148 MW
ADVANTAGES OF GAS TURBINES 1. Short time to start up- It is able to reach full running speed within few minutes (about 15 minutes for medium size). 2. Does not need a lot of accessories like steam turbines 3. Need very little cooling water 4. Can be transported to the site as self contained units. 5. Gas turbines can operate on different kinds of fuels – natural gas, LPG, diesel, fuel oil, etc. It is used in locations where natural gas is cheap and available. 11
ADVANTAGES OF GAS TURBINES 6. The speed of the turbine can be changed to match the requirements of the driven equipment. This is very useful when driving centrifugal compressors. 7. Gas turbines run “smooth”, unlike internal combustion engines (gas engines or diesel engines). This allows much lighter base plates and support structures. 8. Gas turbines have a very high starting torque and can be started up when the driven equipment is loaded. Gas engines and electric motors have poor starting torque.
12
DISADVANTAGES OF GAS TURBINES 1. Cost is much greater than for a similar-sized ICE (very high-performance, strong, heat-resistant materials needed); 2. Use more fuel when idling compared to ICE- not so good unless in continual operation. 3. High efficiency of gas turbines can be achieved through high turbine inlet temperatures of up to 1300 °C. This process requires expensive material and complex technologies for blade cooling. Therefore gas turbines of highest efficiency are very maintenance intensive. 13
IDEAL CYCLE Efficiency = output/input | Output = Turbine power – Compressor power = K.E. | Input = Fuel energy |
Ways to Improve the Overall Efficiency and The Output | Regeneration | Turbine reheat | Compressor intercooling | Steam or water injection |
2. Inter cooling 9
Intercooler
Combustor 4.5
Inlet
1
5
2 3
Compressor 1
Compressor 2
4
Turbine
Power Turbine
net output work
Adding intercooler between LP comressor (compressor 1) and HP compresssor (compressor 2) increase the amount of air which enters the combustion chambers
REHEAT CYCLE
A GAS TURBINE CYCLE WITH STEAM INJECTION
IMPROVEMENT OF THE BASIC CYCLE 1. REGENERATION
The exhaust gases is used to heat the water before it enters the boilers in steam generation cycle
IMPROVEMENT OF THE BASIC CYCLE 1. Regeneration 9 Regenerator
5.5 3.5 Inlet
1
2
3
4.5
5
Combustor
4
Compressor
Turbine
Power Turbine
net output work
The exhaust gases is used to heat the air before it enters the combustion chambers
COMBINED CYCLE PLANTS |
The major components that make up a combined cycle are the gas turbine, the HRSG and the steam turbine
ENERGY DISTRIBUTION IN A COMBINED CYCLE POWER PLANT.
THE TURBINE BASIC COMPONENTS
| 1.Axialflowcompressor(rotor+stator) | 2.Combustionchamber(s)+transitionpieces | 3.Turbinerotor(turbinewheelsfixedtotheshaft+
turbinefixednozzles)
23
THE TURBINE BASIC COMPONENTS
1. Single Shaft
THEROLEOFAIRCOMPRESSORINTHEGASTURBINE
¾
Thecombustionchamber(combustion,dilution)
¾
Coolingpurposes(tocoolturbineblades)
¾
Bearingcoolingandsealingair
¾
Tooperatethepneumaticcontrolsystem
27
AXIAL FLOW COMPRESSOR PRINCIPLES OF OPERATION |
1. Axial flow and compression occur parallel to the rotational axis of compressor
|
2. Axial compressor consists of a series of rotor blades and stator vanes
|
3. A rotor and the following stator make up a stage
|
4. Several stages are combined to make up the complete compressor
|
5.Kinetic energy of the rotor is transferred to the air
|
6. Stator vanes are placed to the rear of the rotor blades
|
7. Stator vanes receive the air at high velocity and act as a diffuser, changing kinetic energy to pressure.
|
8. Stator vanes have a secondary function of directing air flow to the next stage of compressor at the desired angle. 28
PRESSURE AND VELCITY IN AXIAL FLOW COMPRESSOR
Rotating blades transfer the kinetic energy of the rotor to the airflow Stationary vanes convert the airflow kinetic energy to pressure
AXIAL COMPRESSOR >SECTION VIEW Turbine wheels Compressor last stage
Compressor casing Bearing # 1
Axial compressor First stage Inlet guide vanes
31
VARIATION OF VELOCITY, AND PRESSURE THROUGH AN AXIAL FLOW COMPRESSORS
EXTERNAL CAUSES AND EFFECTS OF SURGE 1. 2. 3. 4. 5. 6. 7. 8. 9.
Restriction in suction or discharge of a system. Process changes in pressure, temperature, or gas composition. Internal plugging of flow passages of compressor (fouling). Inadvertent loss of speed. Instrument or control valve malfunction. Malfunction of hardware such as variable inlet guide vanes. Operator error Maldistribution of load in parallel operation of two or more compressors. Improper assembly of a compressor, such as a mispositioned rotor.
COMBUSTION CHAMBERS 1.Thecombustionchamberconsistsofanoutercasing,aninner perforatedliner,afuelinjectionsystem,andastartingignitionsystem. 2.Thefunction:Thecombustionprocesshappeninsideit.Thiswilladd heatenergytotheflowinggases,therebyexpandingandaccelerating thegasesintotheturbinesection 3.Whenthefuelheatisadded,thevolumeofthegasisincreasedand, remainingthesame,thiscausesanaccelerationofgasestooccur. 4.Interactionofoxygenmoleculesandmoleculesoffuelwhichare heatedtoignitiontemperaturesresultsincombustion 5.Thecombustionchambermustcoolhotcombustionproductstoa temperaturewhichtheturbinesectioncomponentscanwithstand (dilution) 34
COMPONENTS All combustion chambers contain the same basic elements: | A casing | A perforated inner liner. | A fuel injection system. | Some means for initial ignition. | A fuel drainage system to drain off unburned fuel after engine shutdown. |
TYPES OF COMBUSTORS
TYPESOFCOMBUSTIONCHAMBERS |
THERE ARE THREE COMMON DESIGNS
|
1. SINGLE COMBUSTION CHAMBER
37
TYPESOFCOMBUSTIONCHAMBERS |
2. ANNULAR COMBUSTION CHAMBER
38
TYPESOFCOMBUSTIONCHAMBERS |
3. MULTI-COMBUSTION CANS
40
3. MULTI-CAN COMBUSTION CHAMBERS
Transition piece
Combustion chamber liner
Turbine nozzle
3. MULTI-CAN COMBUSTION CHAMBERS
COMBUSTION CHAMBER
43
COMBUSTION LINER &TRANSITION PIECE
45
THE TURBINE PRINCIPLE |
Pressureofhotgasesleavingthecombustionchamberis convertedtovelocityatthenozzlesformedatthetrailingedge oftheturbinestatorsvanesandrotorblades.
|
Theturbinestatorvanesactasnozzles,increasingvelocityand decreasingpressure.
|
Theturbinestatorvanesalsodirectthegasesattheoptimum angleintotheturbinerotorblades.
|
Thevelocityreferredtoisvectoredinatangentialdirection ratherthanaxial.Thisslowsthegasflowaxially,reducingits reactivepower,butaddsshaftpowertotherotorsystem. 46
TURBINE ENGINE (GAS GENERATOR)PARTS
47
PATHS OF PRESSURE,TEMP.&VELOCITY IN F5GT
48
FIRING TEMPERATURE INCREASE WITH BLADE MATERIAL IMPROVEMENT
THE TURBINE STATOR (TURBINE FIXED NOZZLES)
First stage fixed nozzle assembly
FRAME 6 - THE TURBINE ROTOR (TURBINE WHEELS) Rotating blades –first stage
Rotating blades –third stage
Rotating blades –second stage
THE TURBINE BLADES - HOW IT IS FIXED TO THE TURBINE WHEEL (OR DISC)?
GAS TURBINES TECHNOLOGY
54
LOAD GEAR BOX
55
THE TURBINE BEARINGS
56
THE TURBINE BEARINGS
Sliding surface bearing
TILTING PADS RADIAL BEARING
THE TURBINE BEARINGS ¾
What is the function of the bearing?
|
To carry the turbine rotor in casing frame and keep it in its correct running position. There are two different kinds of bearings: radial and thrust bearings.
¾
What is the most common type of bearings?
|
Journal bearing or tilting pad bearings (Radial bearing)
|
Tilting pad bearing & Taper land (Thrust bearing)
59
SELF EQUALIZING TILTING PADS THRUST BEARING COMPONENTS
TILTING PADS THRUST BEARING
What is active bearing and un-active bearing?
27. Generator Components
PRESSURE
MECHANICAL
INCREASE
ENERGY
COMPRESSOR GAS
GAS Suction Pressure = Ps Suction Temperature = Ts Suction Velocity = Us
Discharge Pressure = Pd Discharge Temperature = Td Discharge Velocity = Ud 63
COMPRESSION METHODS
Compressors
Continuous Flow
Intermittent Flow Positive Displacement
Reciprocating
Rotary
Mechanical Piston
Sliding Vane Liquid Piston Helical Lobe Straight Lobe
Dynamic
Ejector
Radial Flow
Mixed Flow
Axial
Centrifugal
Mixed Flow
Axial 64 flow
TYPICAL APPLICATION RANGES OF COMPRESSOR TYPES
65
CROSS SECTION OF HORIZONTAL SPLIT Discharge volutes Impellers Drive coupling
Impeller inlet labyrinth seals Shaft and labyrinth seal Journal bearing
Casing (horizontally split flange) Compressor discharge nozzle
Thrust bearing
Compressor inlet nozzle
66
PICTURE OF HORIZONTAL SPLIT
67
PICTURE OF BARREL TYPE COMPRESSOR
68
69
ROTOR SHAFT WITH IMPELLERS
70
CENTRIFUGAL COMPRESSORS
DIAPHRAGMS
71
72
Thrust Load &Thrust Control Pressure Thrust on Impeller
73
ON THE DISC SIDE THE IMPELLER IS EXPOSED TO DISCHARGE PRESSURE AND ON THE OTHER PARTLY TO THE SAME PRESSURE PARTLY TO SUCTION PRESSURE.
THUS A THRUST FORCE IS CREATED TOWARDS SUCTION.
74
75
THRUST LOAD &THRUST CONTROL
II- IMPELLER ARRANGEMENTS
in a back-to-back arrangement and changing the flow path of the gas within the casing minimizes axial thrust (Figure 18).
This arrangement is used when a high-pressure rise Figure 18 is required within Back-to-back impeller arrangement a single casing. 76
THRUST LOAD &THRUST CONTROL
II- IMPELLER ARRANGEMENTS
In double flow arrangement, which doubles the maximum flow capability of the compressor but in turn reduces the discharge pressure ( Figure 19).
Figure 19 Double flow arrangement 77
THRUST LOAD &THRUST CONTROL
THRUST BEARINGS
NOTE Thrust bearing failure is one of the worst types of failure that can occur in a dynamic compressor. Due to the high rotational speeds and the close clearances between the stationary and rotating elements, any contact due to shaft movement results in instant compressor failure.
78
MAIN COMPRESSOR TROUBLES a) Surge -
Surging occurs when the inlet flow rate is less than the minimum recommended rate or when the back pressure cannot be overcomed by the compressor discharge
b) Stonewall (Choked Flow) -
Stonewall occurs when the compressor operates at maximum flow and minimum head. Stonewall causes a drop in Pd and an increase 79 in vibration.
ANTI-SURGE CONTROL Possible damages caused by surging can be ...
• Thrust Bearing Failure • Rubbing of labyrinth strips causing higher clearances and consequentely higher leakages / thrust forces • Rubbing of impellers / blades • Failure of blading on axial compressors due to excess stress/heating • Damage to suction filter, silencers, process armatures etc. 80
SURGE EFFECT ON G.T. AIR COMPRESSOR
81
BASIC ANTISURGE CONTROL SYSTEM • The antisurge controller UIC-1 protects the compressor against surge by opening the recycle valve • Opening of the recycle valve lowers the resistance felt by the compressor , This takes the compressor away from surge • The essence of the surge protection is to determine when and how much to open or close the recycle valve Rc
VSDS
Rprocess Rprocess+valve
Compressor
Suction
F Ps P 1 1 1 T T dT U 1 I C
Discharge 2
qr Surge parameter based on invariant coordinates Rc and qr y y
82
Flow measured in suction ('Po) Ps and Pd transmitters used to calculate Rc
GAS TURBINE INSTRUMENTATION
Control Devices P&I
83
MEASUREMENT Things that are measured include: | Pressure, temperature, level, flow, humidity, speed, motion, position, weight, density, conductivity, pH, light, quality, quantity, and more. Devices that process or do the measuring are called: | Sensors, transducers, transmitters, indicators, displays, recorders, data loggers, and data acquisition systems. 84
FINAL CONTROL ELEMENTS These are the devices the controller operates: |
Pneumatic valves, solenoid valves, rotary valves, motors, switches, relays, variable frequency drives.
85
THE PRESSURE GAUGE PANEL Placedintheauxiliarycompartment,mountedonit:thepressuregauges, pressureswitchesandtestvalvearefitted. 1)
LUBEOILHEADER
2)
AUX.LUBE OIL PUMP DISCHARGE
3)
EMERGENCYLUBEOILPUMPDISCHARGE
4)
MAINLUBEOILPUMPDISCHARGE
5)
COMPRESSORDISCHARGE
6)
HYDRAULICOILHEADER
7)
TRIPOILHEADER
8)
MAINFILTERDIFFERENTIAL
9)
TRIPOILFILTERDIFFERENTIAL
10)
HYDRAULICOILFILTERNO.1DIFFERENTIAL
11)
HYDRAULICOILFILTERNO.2DIFFERENTIAL
86
CPD & FUEL GAS PRESSURE TRANSMITTER (96CD../FG.) ¾
Thetransmitterconsistsofacasinginwhichamembraneonwhichthe compressordischargepressureisacting.Internally,themembraneis connectedtofourstraingauges(lengthsensitiveresistances),whichisDCfed fromtheSpeedtronicpanel.
¾
Achangeincompressordischargepressurewillresultinachangeofoutput dcvoltageofthebridge.
87
FLAME DETECTORS (28FD..) ¾
Theflamedetectionsystemcomprises2primary&2secondarydetectors
1.beforestartingtheturbine,allflamedetectorsmustsignal"noflame present";ifnotstartingisnotpossible. 2.duringthestartingsequenceandoperation,atleastoneprimarydetector mustsignal"flamepresent"topreventtheturbinefromtripping. 3.duringstartingandoperationanalarmwillsoundwhenoneofthedetectors failstoseeflame.
88
GAS TURBINE SPEED PICKUPS (77NH...,77HT...) |
whenatoothpassesthepickuptip,themagneticfieldofthepermanent magnetwillchangethroughwhichavoltageisgenerated.Thishappens60 timesperrevolutionofthegearwheel,resultingin:
89
SEISMIC VIBRATION PICKUPS (39V...) ¾
Thepickupsaresocalledseismicorvelocitypickups.Theyproducea signalwhichisproportionaltothevibrationvelocityinrespecttospace. ThesignalsaresenttotheSpeedtronicpanelwheretheypassfilters,to comparewiththefixedalarmandtripvalues.
90
DISPLACEMENT VIBRATION PICKUPS (39VS.,77RP.,96VC.) ¾
Thebearingsareequippedwith"proximityprobes".Theyarenoncontactingdevices, measuringthedisplacementmotionandpositionofanobservedsurfacerelativeto theprobemountinglocation.Theyoperateonthe"EddyCurrent"principle. Connectedtotheprobe,wefindanoscillator/detector/amplifiercombination, frequentlycalled"Proximitor".Itisasignalconditioningdevice,whichsendsaradio frequencysignaltoanEddycurrentproximityprobe,demodulatestheprobeoutput, andprovidesoutputsignalsproportionaltoboththeaverageanddynamicprobegap distances.
91
92
93
KEY PHASOR PROBE | GT,compressorandgearboxhaveeachbeenprovided
withanadditionalaxialprobe,whichfunctionsasakey phasor. | Eachprobeobservesagroove,machinedintheshaft. Thegrooveprovidesasocalledonceperturnevent whichwillprovideavoltagepulseeverytimethe groovepassesthekeyphasorprobe. | Thekeyphasorpulseprovidesareferencemarkfor phaseangle,frequencymeasurementsandallvibration dataacquisition. 94
95
ELECTROHYDRAULIC SERVO VALVES (MOOG) ¾
Theservovalveistheinterfacebetweentheelectrical(Speedtronic)&the mechanicalsystems.Itconvertstheelectricalsignalcontrolsystemtoa hydraulicsignali.e.anoilflowcausingpistondisplacement.
¾
Servovalvesareusedtocontrolthedirectionandrateofmovementofthe pistons,positioningthegasandliquidfuelvalvesandtheIGV’s.
96
LVDT POSITION TRANSMITTERS ¾
Thepositionofthevalvestemsofthegasfuelcontrolvalve,thestop/speed ratiovalveandoftheinletguidevanesismeasuredbypositiontransmitters calledlinearvariabledifferentialtransformers
¾
TheLVDTconsistsofaprimarytransformerwinding,poweredfroma7V,3.2 kHzACsource.Thesecondarywindinggeneratesanoutputsignalbetween 0.7and3.5V,dependingonthepositionofthecoreinbetweentheprimary andsecondarywindings.
97
IGNITION TRANSFORMER 95TR1&SPARK PLUGS 95SP1,10
Sparkplugsoncombustionchambers1and10.
98
EXHAUST THERMOCOUPLES FOR TX (TTXD...) ¾
Thereare(13/fr5)(18/fr6)thermocouplesincorporatedinthetemperature controlandprotectionsystem.Thethermocoupleitselfisajointoftwometal alloys(ChromelandAlumel).
99
100
TURBINE WHEELSPACE THERMOCOUPLES (TTWS…)
101
BEARING METAL TEMPERATURE (RTD…,BT…)
102
DEVICE CODING SYSTEM |
ThedevicesintheDeviceSummaryandonthePipingSchematicshavebeen codedaccordingtothefollowingAmericanstandards:
¾
NEMAstandardSM32
¾
AmericannationalStandardInstituteC37.2
¾
IEEEInternationalStandards
|
Nexttothenumbertwocharactersareusedtoindicatetheapplicationofthe
|
device.
|
Examples:
¾
20CB1solenoidvalveforCompressorBleed
¾
63PF1pressureswitchVentilationfan
¾
45FT1FiredetectorTurbinecompartment
¾
96FG1pressuretransmitterFuelGas
103
DEVICE CODING SYSTEM
104
DEVICE SUMMARY (INSTRUMENTATION LIST) |
TAGNO.SCHDESCRIPTIONITEM
REV.
|
|
5ES1
CD
EMERGENCYSTOPPUSHBUTTON
|
Extrainformation:
|
Make
:
ABB
|
Model
:
P411/5312
|
TIpartno
:
3047.2231.010
|
63QA2
LO
11122
Keyresettype
LOWLUBEOILPRESSUREAUX.PUMPSTART09260
|
ContactType:
SPDT
|
Action:
NOOA
|
Setting:
Decreasingopenat0.8+ 0.1Bar
|
(Reset):
(Increasingcloseat1.l+0.1Bar)
|
Make:
CustomControl
|
Model:
646GEA2
|
TIpartno:
3032.1229.000
|
77HT2 CD
TURBINEROTOROVERSPEEDMAGNETICPICKUP05460
|
GapSetting
|
CoilResistance :
:
170210ohms
1.3t0.1mm
|
Make
:
Airpax
|
Model
:
0851010404
105
P&IDLEGEND
106
ALARM &TRIP LIST
107
CAUSE & EFFECT DIAGRAM
108
LUBE OIL SYSTEM
109
ELECTRICAL DRAWINGS
110
ELECTRICAL DRAWINGS
111
ELECTRICAL DRAWINGS
112
TURBINE SUPPORTING SYSTEMS 1.Thestartingsystem Thesystemconsistsofanelectricstartingmotortowhichatorqueconverteris connected.Viaarejectable jawclutch,theaccessorygearboxandtheaccessory coupling,thegasturbineisdriven. 2.Thelubeoilsystem Themajoritemsofthissystemare:themainpump,theauxiliarypump,the emergencypump,filters,coolers,controllersandprotectiondevices. 3.Thetripoilsystem Thissystemisfedfromthemainlubeoilsystem.Assoonasthelubeoilsystem ispressurized,thetripoilsystemwillenableopeningthefuelstopvalveandthe inletguidevanes.Incaseofatripsituation,thetripoilsystempressurewill immediatelyfalltozeroviasolenoidvalves,causingthefuelsupplytobecutoff andtheIGV'stocloseimmediately. 4.Thefire/gasprotectionsystem 113 Thesystemcontainsseveralthermalandopticalfiredetectors,whichareable toactivatethefirefightingequipment.
TURBINE SUPPORTING SYSTEMS 5.Thehydraulicoilsystem Highpressurepumpsandservovalvesforthefuelvalvearethemain componentsofthe system.ThesystemservesthegasfuelcontrolvalvesandtheIGVcontrol system. 6.Thegasfuelsystem Thissystemconsistsofanoffbasefuelgassupplysystemandanonbase controlsystem.Thelattersystemconsistsofcontrolandshutoffvalvesforgas fuelsupplycontrolandforDryLowNOxoperation. 7.Thesteaminjectionsystem ToreducetheNOxemissionsasteaminjectionsystemmaybeimplemented. Thissystemcontainsthenecessaryvalvesforwaterdrainage,preheatingand controllingtheamountofsteam.Steaminjectioncanalsobeusedforpower augmentation. 114
TURBINE SUPPORTING SYSTEMS 8.Theliquidfuelsystem Anaccessorygearboxdrivenpumppressurizesthefuel.Aservocontrolledby passvalveperformscontrol.Viaafilter,fuelisdirectedtoaflowdividerfor equaldistributiontothecombustionchambers. 9.Theatomizingairsystem Foroptimumcombustionoftheinjectedliquidfuel,thissystemprovides atomizingair,whichisinjectedintothefuelnozzle.Thesystemcomprisesa centrifugaltypemaincompressorandascrewtypeauxiliarycompressorbeing drivenbythestartingmotor.Asthisairistakenfromtheaxialflowcompressor, theairiscooledbackinacooler. 10.Compressorwashingsystem Afouledcompressorcanbecleanedintwoways:offlinecleaningandonline cleaning.Systemsforbothcleaningmethodshavebeenprovided.Bothsystems willreceivewater/detergentfromanoffbasewashskid. 115
TURBINE SUPPORTING SYSTEMS 11.Thecoolingandsealingairsystem Thissystemisfedwithcompressedair,whichistakenfromthecompressoron severalplaces.Theairissent,viainternalchanneling,tothehotpartsand bearingsofthegasturbine.Valves,filtersandpneumaticcylindersarepartsof thissystem. 12.Heatingandventilationsystem Thesystemwilltakecareofacontinuousflowofairthroughtheauxiliary compartmentandaroundtheturbine.Whentheturbineisstopped,theheating systemwillprovidewarmairtocirculatethroughtheauxiliarycompartmentto preventanycondensation. 13.Inletandexhaustsystem Thissystemprovidescleanairtothegasturbineandexhauststhehotgasesto thestack.Thesystemconsistsoftheairinletfilter,theinletducting,theinlet plenum,theexhaustplenumandtheexhaustducting. 116
STARTING SYSTEM Starting system fall into two categories: 1. Those that drive the gas generator directly and 2. Those that drive the gas generator through an intermediate gear box Starters may be: 1. Diesel or gas engine 2. Steam turbine 3. Electric, hydraulic, or pneumatic motors 117
118
GAS/DIESEL ENGINES y
Available up to 3 MW
y
Usually turbocharged
y
Variable speed capability
y
Typical operating speed is
y
600-1800 rpm
y
Easy start from (dead bus)
119
ELECTRIC MOTORS y y y y y y y
Variable speed drive motors are available High efficiency / Low maintenance Poor starting torque Require pressurized or explosion proof enclosures High current draw during start-up No emissions Relatively expensive 120
STEAM TURBINES
Used where excess process steam is available from plant operations and may be directly coupled or driven through a gearbox
121
STARTING SYSTEM What is the function of starting system? 1. Drive the gas generator compressor to purge the gas generator and exhaust duct of any volatile gases prior to initiating the ignition cycle. 2. To rotate the gas generator until it reaches its self – sustaining speed (about 25% of full speed) 3. To rotate the gas generator, after shutdown for cooling
122
123
124
125
126
127
128
129
HYDRAULIC CONVERTOR
Input speed is constant value
Output speed is variable value
131
132
133
134
135
136
137
138
139
140
141
142
143
LUBRICATION OIL SYSTEM
What is the function of lubricating oil system in the turbine? To provide the required clean pressurized lubricating oil to all required points in the turbine with suitable temperature (bearing, spacer gear coupling and gearboxes in the system). This lubricating oil perform two jobs: 1. Lubricate the parts 2. Cooling of these parts 144
TURBINE LUBRICATING OIL SYSTEM 1. Gas turbines generally have separate external circulation systems. 2. Bearings are used to support the weight of the shafts, rotors and prevent them from vibrating radially. 3. Without a lubricant, the bearing surface would wear out quickly. 4. Oil is supplied to bearing through machined holes and grooves. 5. The oil forms a film between the rotating shaft and the bearing that separates them. This reduces friction and heat. 6. Some heat is generated and the lubricant must carry it away. 7. To re-use this oil, it must be cooled, cleaned and re-pressurized. 145
146
147
148
149
150
151
152
153
154
Lubrication-, Control- and Seal Oil Systems Oil Pumps
Drivers of pumps: Direct (shaft driven)
or
Steam turbine
or
Electric motor
155
156
157
158
159
Lubrication-, Control- and Seal Oil Systems Oil Pumps
Main oil pump shaft-driven (MAN Standard):
Shaft-driven pumps are gearor screw type
160
161
162
163
164
Lubrication-, Control- and Seal Oil Systems Temperature Control Valve
165
166
167
168
169
170
171
15 “C 172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
192
COMPRESSOR >SECTION VIEW Turbine wheels Compressor last stage
Compressor casing Bearing # 1
Axial compressor First stage Inlet guide vanes
193
194
195
196
197
198
199
200
201
202
203
2ND STAGE NOZZLE CONTROL |
WhyNozzles y
|
Startup y y
|
SecondstageNozzlesallowtheHPturbinetorunatitsoptimal speedforbetterfuelefficiency.TheyremainatEGTlimit
Nozzlesareopenduringstartup CloseatNHPidlespeed
WhichGT’shasthem y y
GeneralElectricFS3002andFS5002 NuovoPignonePGT5andPGT10
204
TWO SHAFT INDUSTRIAL GAS TURBINE
205
206
2ND STAGE NOZZLE ASSEMBLY
207
TRIP OIL SYSTEM
208
E
209
210
211
212
213
214
215
216
217
218
219
Same for 20FG-1 (Gas Stop Valve)
220
Fuel system | The
purpose of the fuel system is to deliver fuel to the individual combustors of the turbine under the following conditions: 1- At the required pressure, 2- In the right quantity to meet the load demand. 3- Free of contaminants which may be harmful to the turbine
222
223
FUEL SYSTEM .
225
226
227
EMISSIONS DURING COMBUSTION |
NOx is the combination of NO (approximately 90%), NO2 and other nitrogen oxides that are emitted from the combustion process in a gas turbine. The major cause for NOx production is a very high temperature during combustion, i.e. in the center of the flame in the combustion chamber (thermal NOx).
|
NOx and moisture in the air forms Nitric Acid (HNO3) and Nitrous Acid (HNO2).
|
SOx, a combination of SO2 (approximately 95%) after combustion in a gas turbine, and SO3 with moisture in the air forms Sulphuric Acid (H2SO4) and sulphurous Acid (H2SO3).
|
These acids are the main cause of ACID RAIN.
|
As a result of several chemical reactions and sunlight (UV rays) NO2 also contributes to the development of Ozone (O3) in the lower atmosphere. Ozone is the main cause of SMOG.
TECHNIQUES FOR EMISSION CONTROL OF:
NOx
- Water- or Steam Injection - Catalytic Combustion - Selective Catalytic Reduction (SCR) end of pipe - Dry Reduction Techniques
SOx
- Sulphur Content in Fuel
CO
- Design of Combustion Chamber (Combustion Efficiency)
CO2
- Efficiency of a Process - Type of fuel
UHC / VOC
- Design of Combustion Chamber (Combustion Efficiency)
Dust
- Fuel and Air Composition
Smoke
- Design of Combustion Chamber - Fuel Composition
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NOX PRODUCTION RATE
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CDP closes the bleed valve (spring loaded to open)
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Dry Gas Seal System The Dry Gas Seal system supplies filtered, and flow- controlled process gas to the shaft seals of the compressor. The seal gas leakage through the shaft seals is released to a safe area, usually a flare system and an overhead vent 262
SHAFT END SEALS
DRYGASSEAL The
stationery mounted seal unit comprises a spring loaded, ’O’ ring sealed carbon face, held as an integral unit in a stainless steel retainer. An 'O' ring sealed rotating seat, normally manufactured from tungsten carbide, is profiled with series of spiral grooves having a depth of between 0.0025 to 0.010mm as illustrated
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SHAFT END SEALS
DRY GAS SEAL
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Dry Gas Seal Systems Working Principle
Filtered Buffer Gas (N2)
EXTERNAL GAS
PROCESS GAS
PCV
Filtered Seal Gas
FILTER MODULE
N2 SECONDARY FILTER MODULE
FO
FO FI
FI
FI
FI
N2 buffered tandem DGS
Process Gas + N2 to Flare PI FO
FO FI
Seal Gas = Process Gas
PI
FI
FLARE
VENT
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N2 to Atmosphere
Dry Gas Seal Systems Possible Calculations
Calculation of a Tandem DGS with OB monitoring z Leakage z Flows z Losses
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Heating & Ventilation system
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Heating & Ventilation system
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FIRE &GAS DETECTION SYSTEM
Fire Triangle
O2 Combustible Media Heat Source 286
FIRE &GAS DETECTION SYSTEM System Components classification
1- Construction ¾
Sealed Enclosures & Doors, Dampers
2- Detection ¾
Temp. switches
¾
Gas detectors
¾
Flame detectors
3- Annunciation ¾
F&G panels alarms to control
¾
Package Sounder & Flash lights
4- Extinguishing ¾
Actuators
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Extinguishing Cylinders (CO2, FM-200,….)
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FIRE PROTECTION P&ID
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FIRE PROTECTION
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GAS DETECTION • OPEN PATH GD
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Controlsystem |isacombinationofcomponentsperforming
Controlfunctions. |Tocontrolmeanstomaintainaparticular
operation,statusorperformanceofa physicalprocess 293
BASIC FUNCTION OF CONTROL SYSTEM Thefunctionsprovidedbythecontrolsystemare:
1.
Sequence
2.
Control
3.
Protect
4.
Display 294
GASTURBINEMONITORINGSYSTEM Thebasicobjectivesinmonitoringgasturbinecharacteristics: 1.Maximizeperformance 2.Reducemaintenance 3.Reduceunitdowntime Monitoringsystemmustbeattentionto: 1.Thethermodynamicgaspath(hotgaspath) 2.Vibrationsofbearings,rotors,andgearboxes 3.Lubrication,control,andotheraccessorysubsystems
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PLCS ¾
ProgrammableLogicControllers(PLCs),areinthecomputerfamily.
¾
APLCmonitorsinputs,makesdecisionsbasedonitsprogram,andcontrols outputstoautomateaprocessormachine.
¾
PLCsconsistofinputmodulesorpoints,aCentralProcessingUnit(CPU),and outputmodulesorpoints.
¾
Aninputacceptsavarietyofdigitaloranalogsignalsfromvariousfield devices(sensors)andconvertsthemintoalogicsignalthatcanbeusedby theCPU.
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TheCPUmakesdecisionsandexecutescontrolinstructionsbasedon programinstructionsinmemory.
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OutputmodulesconvertcontrolinstructionsfromtheCPUintoadigitalor analogsignalthatcanbeusedtocontrolvariousfielddevices(actuators).
¾
Aprogrammingdeviceisusedtoinputthedesiredinstructions.These instructionsdeterminewhatthePLCwilldoforaspecificinput.
¾
Anoperatorinterfacedeviceallowsprocessinformationtobedisplayedand 296 newcontrolparameterstobeentered.
PLCS
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ADVANTAGES OF PLCS ¾ ¾ ¾ ¾ ¾ ¾ ¾ ¾ ¾
Smallerphysicalsizethanhardwiresolutions. Applicationscanbeduplicatedfasterandlessexpensively. Easierandfastertomakechanges. PLCshaveintegrateddiagnosticsandoverridefunctions. Diagnosticsarecentrallyavailable. Applicationscanbeimmediatelydocumented. Flexibleandcanbereappliedtocontrolothersystemsquickly andeasily. Troubleshootingaidsmakeprogrammingeasierandreduce downtime. Reliablecomponentsmaketheselikelytooperateforyears 298 beforefailure.
RELAY LOGIC IN A PLC push buttons
power supply +24V com.
PLC inputs
ladder logic
A
B
C
outputs
115Va c
light
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AC power neut.
READING LADDER LOGIC HOT
NEUTRAL A
B
X
C
D
G
E
F
H
INPUTS
Y
OUTPUTS
Note: Power needs to flow through some combination of the inputs (A,B,C,D,E,F ,G,H) to turn on outputs (X,Y).
¾ TheRLDformisbasicallyaBooleanelectricalform,Ithasbeenderivedfromthe relaydiagramswhereaninputtriggersanoutput. ¾ Flowgoesfromlefttorightandallrungsareexecutedfromuptilldown.In principlethelogicalANDandORfunctionsareusedtospecifythelogicoperations.
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PRIMITIVES ¾
Aprimitiveisasimplesoftwarefunction,liketimers,adders, comparators,optionallyconnectedtoladderlogic.These “primitives”canbefoundinthe\PROMdirectorywherealsoBBL’s canbefound.Followingoftenusedprimitivesarebeingdisplayed hereunder:
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PRIMITIVES
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BBLBIG BLOCKS ¾
Abigalgorithm(bigblock)isafixedpieceasoftwarewhichisa compositionofprimitivesandRLD’s.
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CONTROL SYSTEM FUNCTION
Thefunctionsprovidedbythecontrolsystemare:
1.
Sequence
2.
Control
3.
Protect
4.
Display
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GAS TURBINE SYSTEM CONTROL OVERVIEW |
ThediagramshowsanoverviewofatypicalgasturbineapplicationforGE typeGasturbines.
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1.CONTROL FUNCTIONS |
StartupControl
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AccelerationControl
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SpeedControl
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LoadControl
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ExhaustTemperatureControl
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InletGuideVaneControl
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FuelControl
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GeneratorExcitation
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EmissionsControl 307
FUEL CONTROL
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FUEL CONTROL |
Sixindependentfuelflowcontrolalgorithmscontinuouslycalculatetheirown FuelvalveStrokeReference.Thenfedtoaminimumselectgatewherethe lowestFuelvalveStrokeReferenceFSR[%],willdeterminefuelflowtoGT
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•StartupFSRSU
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Thiscontrolalgorithmsetsthefuelflowtotheignitionandwarmuplevelsand initiatesthegradualraiseoffuelflowforacceleration.whenstartupofthe turbinehasbeenaccomplishedthisFSRwillberampedtill128%
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•AccelerationFSRACC
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Fuelflowisadjustedbyanaccelerationcontrolloop,whichreducesthefuel flowincaseoftoohighaccelerationoftherotor,e.g.causedbylossoffull load.Thispreventsexcessiveaccelerationtorques.Whentheturbinerunson 95%speedtheFSRACCwillberampedabovetheactualFSRlevelbutnearby
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•Speed/loadFSRN
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Fuelflowisadjustedinsuchawaythattheloaddemandismaintained.The speed/loadFSRwillbeactivatedwhenabove95%.Itassuresforproper synchronizationandwillrampthespeedreferencetillbaseload.WhenBase 310 loadhasbeenachievedtheFSRNwillberampedabovetheactualFSRTlevel, butnearby.
FUEL CONTROL |
•TemperatureFSRT
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Fuelflowisadjustedinsuchawaythatthefuelflowcanbereducedto preventoverheatingofthegasturbine.WhenFSRTisthe(lowest)oftheFuel valveStrokeReferencesthegasturbineisonmaximumload.isactivewhen theexhausttemperaturereachesthetemperaturecontrolline.
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•ShutdownFSRSD
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Thiscontrolreducesthefuelflowduringanormalstop(firedshutdown)from themomentthatthegeneratorbreakerhasopeneduntilflameextinguishes. TheShutdownFSRisalwaysat100%atgtrunning,startup,loadingorat tempcontrol.willbeactivatedwhengeneratorbreakeropenedGTcoasting down
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•Manualcontrolloop FSRMAN
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TheoperatorcanenteravalueforFSRMAN,theoutputofthisFuelvalve StrokeReferencealgorithm.InthiswayanupperlimitforFSRisestablished.It isnotoftenused,thatmeansFSRMAN=100%isthedefaultvalue.The 311 manualFSRwillbeusedforcalibratingandtestingpurposes.
FUEL CONTROL DIAGRAM
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START UP CONTROL LOOP BBL |
The“startupfiring”FSR(L83SUFI)willcontrolthestartupalgorithmcausingtheFSRtobe exactlytheConstantFSKSU_FI,whichisthefiringFSR.Whenthepurgetimerhasbeentimedout (L2TVX)theLogicwillbeset.
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Whenflameisdetected(L28FDZ)thelogicL83SUWUwillcontrolthealgorithmcausingthe constantFSKSU_WUexactlybetheFSR.
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WhenL2WXishigh(Turbinewarmupcompleted)thestartupalgorithmwillincreasefuel.The FSRAcceleratecontrolsthestartup(L83SUAR).
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ThemaximumFSRisbeinggeneratedwhengeneratorbreakerisclosed,logicL83SUMXcontrols theMaximumFSRforthestartupalgorithm
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STARTUP SPEED SEQUENCING Properspeedsensingisnecessaryforthelogicsequencesinstartup.The followingspeeddetectorsandspeedlogicrelaysareused: |
L14HR;ZeroSpeedDetector(approximatelyo%speed),providesthesignal whentheturbineshaftstartsrotating.
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L14HT;TurningGearOperationSpeedRelay(approximatelyo.5%speed), indicatesthatturninggearisrunningwhichpermitsstarteroperation.
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L14HM;Min.FiringSpeedRelayDetector(approx.15%speed), indicates thatgtreachedmin.firingspeed&initiatespurgepriortoignition.
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L14HP;PurgeSpeedRelaydetector(approximately25%speed),indicates thattheshafthasachievedpurgespeed.ThisspeedishelduntilthePurge Timertimesout.
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L14HA;AcceleratingRelaySpeedDetector(approx.50%speed),indicates thatgtreachedapprox.50percentintheaccelerationcycle.
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L14HS;HighSpeedrelay(approximately95%speed),indicatesthatturbine isatoperatingspeed.andthattheacceleratingsequenceiscomplete. 315
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GENERATOR RATED SPEEDS
1800rpm
1200rpm
900rpm
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AVR
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PROTECTION |
Theprotectionsystemsprotectthegasturbineagainstdangeroussituations thatcouldoccurduetoamechanicaldefectinthegasturbineorduetoa malfunctioningcontrolsystem.
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Thefollowingprotectionsystemshavebeenprovided:
1)
Flamedetection Vibrationdetection(gasturbineandgenerator) Overtemperatureprotection CombustionMonitor Overspeedprotection(softwareandhardwaresystem); Fireprotection Intheauxiliarysystemspressureswitches,levelswitches, temperatureswitcheswillalarm&triptheunitwhenabnormal 321 situationsoccur.
2) 3) 4) 5) 6) •
MKV PROTECTION OVERVIEW
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1FLAME DETECTION PROTECTION
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Theredundantcomputersreceivesignalsfromallthefourflamedetectors. Lossofflamesignalbyoneortwoflamedetectorsisalarmed,ifanother 323 signalislostthegasturbineistripped.
1-FLAME DETECTION | The
SPEEDTRONIC Mark VI flame detectors perform two functions, | one in the sequencing system | and the other in the protective system
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2VIBRATION PROTECTION |
Seismic(velocity)VibrationTransducersaremonitoreddirectlybytheMark VI,Consistsofatleastof2vibrationsensorsonbrg1&2onbrg2,andpossibly sensorsonthegearboxandthedrivenload.Eachvibrationsignalhasanalarm /tripsetting.Acombinationofalarmsandtripswithinagroup(gasturbine, gearbox,drivenload)willissueatripsignal.
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•Astartcheckpermissiveisinhibitedifthreeormoreturbinesensorsortwo ormoregeneratorsensorsaredisabledorfaulty.
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•Anautomaticshutdownsequenceisinitiatedifallturbinesensorsare disabledorfaulty.
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•Atripisinitiatedifoneturbinevibrationsensorindicatesatriplevelandany otherturbinesensorindicatesanalarmlevel.
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•Atripisinitiatedifoneturbinevibrationsensorindicatesatriplevelandany adjacentpairofturbinesensorsaredisabledorindicatesanalarmlevel.
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•Atripisinitiatedifoneturbinevibrationsensorindicatesatriplevelandtwo ormoreinputsaredisabled.
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326 BentlyNevadaProximitorsformonitoringonly,canbesuppliedaseitheran interfacetoaBentlyNevada3300orasadirectinterfacetotheturbine control.
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3OVERTEMPERATURE |
Theovertemperaturesystemusesthecontrolthermocouples comparedtocertainsettings;
¾
FromtheexhaustthermocouplesanaverageTTXMiscalculated whichiscomparedwithanalarm(14°Caboveactualmaximum temperature)&tripset(23°Caboveactualmaximum temperature) Tripiftheexhausttemperature(TTXM)reachestheisothermal setting1100deg.F(593deg.C). Tripiftheexhausttemperature(TTXM)is40deg.F(22deg.C) abovethetemperaturecontrolreference(TTRXB). Tripiftheexhausttemperature(TTXM)isbelow250deg.F(133 328 deg.C)whenturbinespeedisabove50%.
¾ ¾ ¾
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3- OVERTEMPERATURE PROTECTION SOFTWARE Overtemperature Alarm (L30TXA) | exhaust TC value (TTXM) is compared with alarm and trip setpoints. “EXHAUST TEMPERATURE HIGH” alarm when (TTXM) exceeds the temperature control reference (TTRXB) plus the alarm margin (TTKOT3) programmed as a Control Constant in the software | Overtemperature Trip (L86TXT) | trip will occur if the (TTXM) exceeds the temperature control reference (TTRXB) plus the trip margin (TTKOT2), or if it exceeds the isothermal trip setpoint (TTKOT1) |
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3- OVERTEMPERATURE PROTECTION SOFTWARE
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BIGBLOCK FOR WHEELSPACE MONITORING | L30WSA1 ALARM:224WHEELSPACETEMPDIFFERENTIALHIGH | L30WSA2 ALARM:225WHEELSPACETEMPERATUREHIGH | L69TWW WheelspaceTemperatureWaterWashPermissive | LK69TWW MaxAllowWheelspaceTempforWwash <300degF>
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5OVERSPEED PROTECTION |
Overspeedprotectionconsistsofaprimaryoverspeedmonitoringsystemin thethreecontrolmodulesandanemergencyoverspeedmonitoringsystem inthebackupprotectionmodule,whichreplacesthemechanicaloverspeed boltusedonolderturbines.
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Eachcontrolmoduleandeachsectionofthebackupprotectionmodule monitorsaseparatepassivemagneticspeedsensor(6total)from2rpmon a60toothwheel.
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InolderGTs
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Twooverspeedsystemsareprovided,amechanicalandanelectronic.The mechanical(bolt)typesystemmechanicallytripstheturbineonoverspeed bydumpingthehydraulicpressurearound113.5%speed.
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Thespeedoftheturbineshaftissensedbymagneticpickupsand,fedinto adetectorwhichoutputsacontactopeningwhenthespeedisbelow 336 approximately10%andabove110%speed.
6FIRE PROTECTION
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3.SEQUENCING |
Theturbinecontrolincludesacompletelyautomatedstartupandshutdown sequence,includinginterfacetoalloftheauxiliarysystemsinthemotor controlcenterandgeneratorprotectionsystem.Operatorscanchooseto havetheturbineautomaticallysequencetointermediateholdpointsby selectingCrankorFirewithoutenablingautomaticsynchronization.
|
Allrampratesandholdtimesarepreprogrammedforoptimum performance,andcountersrecordthenumberofstarts,shutdowns,tripsand runningtimeundervariousconditionsinnonvolatilememory.Countersand timersforaPG5PA,gasfuelturbineareasfollows:
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Timers&Counters
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ManuallyStarts
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Firedstarts
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EmergencyTrips
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FiredHours
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3.TURBINE CONTROL SEQUENCES
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THIS SCREENSHOOT IS ONLY FOR DEMO, REAL VIEW MAY BE DIFFERENT
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THIS SCREENSHOOT IS ONLY FOR DEMO, REAL VIEW MAY BE DIFFERENT
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THIS SCREENSHOOT IS ONLY FOR DEMO, REAL VIEW MAY BE DIFFERENT
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THIS SCREENSHOOT IS ONLY FOR DEMO, REAL VIEW MAY BE DIFFERENT
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THIS SCREENSHOOT IS ONLY FOR DEMO, REAL VIEW MAY BE DIFFERENT
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COMPRESSOR WASH SEQUENCE
What is compressor fouling? Compressor fouling occurs due to foreign materials deposits on the air foils (compressor blades).
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COMPRESSOR FOULING | compressor
fouling to the extent that airflow is reduced by 5%, will reduce output by 13% and increase heat rate by 5.5%. | On-line compressor wash systems are available that are used to maintain compressor efficiency by washing the compressor while at load, before significant fouling has occurred. | Off-line systems are used to clean heavily fouled compressors
COMPRESSOR FOULING
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“Detergent Isolation Valve Remains Closed”
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4.DISPLAY (MONITORING OPERATOR SCREENS) |
Theoperator/maintenanceinterfaceiscommonlyreferredtoastheHuman MachineInterface(HMI).ItisaPCwithaGECIMPLICITYgraphicsscreen system,aMicrosoftWindowsNToperatingsystem,aControlSystemToolbox witheditorsfortheapplicationsoftwareandunitspecificscreens.This interfacecanbeappliedas:
|
•primaryoperatorinterfaceforoneormultipleunits
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•backupoperatorinterfacetotheplantDCSoperatorinterface
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•gatewayforcommunicationlinkstoothercontrolsystems
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•permanentortemporarymaintenancestation
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•engineer’sworkstation
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Allcontrolandprotectionisresidentintheturbinecontrol,whichallowsthe HMItobereinitializedorreplacedwiththeturbinerunningwithnoimpact onthecontrolsystem.TheHMIcommunicateswiththeprocessorcardinthe turbinecontrolviatheEthernetbasedUDH. 406
4.OPERATOR SCREENS
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MK V RUNG DISPLAY |
•Asolidgreenboxorcircleindicatespowerflowthroughanycontactorcoil.
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•Asolidgreenboxorcirclewithan"F"(or">")Forcedpowerflowthrough thecontactorcoil,whileemptyyellowboxorcirclewithan"F"(or">")inthe middleindicatesnopowerflowduetoaForce.
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•Aninvertedcoilisshownasacoilwitha"/"throughit.Aninvertedcoil withavalueof"0"isconsideredtobepickedupandthereforeisshown asasolidgreencoilwitha"/"throughit,whileinvertedcoilwithavalue of“1"isconsideredtobedeenergized&isshownasaemptyboxwitha"/" throughit.
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MK V ALARM LIST
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REAL TIME PLOTS
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CONTROL CONSTANTS ADJUST DISPLAY
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LOGIC FORCING DISPLAY
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PASSWORD ADMINISTRATION
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AUTO CALIBRATE DISPLAY
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MK VIRLD
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BASICS OF SPEEDTRONIC CONTROL
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SPEEDTRONIC MK V PANEL
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BASIC CONFIGURATION OF MK V
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MK VI CONTROL PANEL
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BASIC CONFIGURATION OF MK VI CONTROL SYSTEM
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MK VI I/O BOARDS
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IOREPORT (ANALOGUE INPUTS)
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IOREPORT (LOGIC INPUTS)
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CSP– CONTROL SEQUENCE PROG.
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TROUBLESHOOTING To effectively troubleshoot poorly performing , follow these steps: 1- Clearly define the problem based on observations and accumulated information. 2- Review available historical system operation. 3- Identify and obtain any additional information and analysis that may be required. 4- Identify and list potential root causes and consider each. 5- Deduce the root cause based on the accumulated information. 6- Execute corrective action.
NEEDED DOCUMENTATION ¾ ¾ ¾ ¾ ¾ ¾
Pipingschematics Devicesummary AlarmlistALARM.LST ControlSequencingProgramCSP.PRN IOListorI/OreportTC2KREPT.TXT MarkVControlSettingsSpecification
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TROUBLESHOOTING |
OverheatingofBearings.
|
Possiblecauses:
|
Oilsupplytemperaturetoohigh
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Incorrectoilquantity
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Incorrectoilpressure
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Incorrectalignment
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Damagedbearing
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LubeOilGaugePressuretooLow.
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Possiblecauses:
|
Fouledoilfilter
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Oilleakage
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Notenoughoilinthereservoir
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Malfunctioningofoilpressurecontroller
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Damagedoilpump
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Reliefvalvesticksopen
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TROUBLESHOOTING |
VibrationLeveltooHigh.
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Possiblecauses
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Malfunctionofthevibrationdetectionequipment
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Fouledordamagedcompressorrotor
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Incorrectalignment
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Incorrectthrustbearingendplay
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Looseorbrokenfoundationbolts
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Compressoroperatinginthesurgearea
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Damagedjournal,orthrustbearing
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AxialDisplacementtooHigh.
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Possiblecauses
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Malfunctionoftheaxialpositiondetectionequipment
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Damagedthrustbearing
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Malfunctioningoftheaxialpositionequipment
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MAINTENANCE STRATEGIES 4 levels of maintenance exist; 1. Reactive or breakdown maintenance. 2. Preventive maintenance. 3. Predictive maintenance. 4. Proactive maintenance.
TURBINE START/STOP CYCLE – FIRING TEMPERATURE CHANGES
MAINTENANCE INSPECTIONS | | | 1. 2. 3.
Standby inspection Running inspection Disassembly inspection Combustion inspection Hot gas path inspection Major inspection
STANDBY INSPECTION This inspection includes routinely servicing the battery changing filters, checking oil and water levels, cleaning relays and checking device calibrations. | Servicing can be performed in off-peak periods without interrupting the availability of the turbine. |
RUNNING INSPECTION | Running
inspections consist of the general and continued observations made while a unit is operating. | This starts by establishing baseline operating data during initial startup of a new unit and after any major disassembly work. | This baseline then serves as a reference from which subsequent unit deterioration can be measured.
OPERATING INSPECTION DATA PARAMETERS
BORE SCOPE INSPECTION
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12,000 hrs
48,000 hrs
24,000 hrs
12,000 hrs
COMBUSTION INSPECTION | The
combustion inspection is a relatively short disassembly shutdown inspection of | Fuel nozzles | Liners | transition pieces | crossfire tubes | Retainers | spark plug assemblies | flame detectors and | combustor flow sleeves.
TYPICAL COMBUSTION INSPECTION REQUIREMENTS | Inspect
and identify combustion chamber components. | Inspect and identify each crossfire tube, retainer and combustion liner. | Inspect combustion liner for TBC wear and cracks. | Inspect combustion system and discharge casing for debris and foreign objects. | Inspect flow sleeve welds for cracking.
TYPICAL COMBUSTION INSPECTION REQUIREMENTS Inspect transition piece for wear and cracks. | Inspect fuel nozzles for plugging at tips, erosion of tip holes and safety lock of tips. | Inspect all fluid, air, and gas passages in nozzle assembly for plugging, erosion, burning, etc. | Inspect spark plug assembly for freedom from binding; check condition of electrodes and insulators. | Replace all consumables and normal wear-and tear items such as seals, lockplates, nuts, bolts, gaskets, etc. | Perform visual inspection of first-stage turbine nozzle partitions and borescope inspect |
TYPICAL COMBUSTION INSPECTION REQUIREMENTS | Perform
borescope inspection of compressor. | Enter the combustion wrapper and observe the condition of blading in the aft end of axial-flow compressor with a borescope. | Visually inspect the compressor inlet and turbine exhaust areas, checking condition of IGVs, IGV bushings, last-stage buckets and exhaust system components.
To perform this inspection, the top half of the turbine shell must be removed. Prior to shell removal, proper machine centerline support using mechanical jacks is necessary to assure proper alignment of rotor to stator, obtain accurate half-shell clearances and prevent twisting of the stator casings. For inspection of the hot gas path , all combustion transition pieces and the first-stage turbine nozzle assemblies must be removed. Removal of the second- and third-stage turbine nozzle segment assemblies is optional, depending upon the results of visual observations, clearance measurements, and other required inspections.
Typical hot gas-path inspection requirements for all machines are: Inspect and record condition of first-, second and thirdstage buckets. Inspect and record condition of first-, second and thirdstage nozzles. Inspect and record condition of later-stage nozzle diaphragm packings. Record the bucket tip clearances Check the turbine stationary shrouds for clearance, cracking, erosion, oxidation, rubbing and build-up.
TYPICAL MAJOR INSPECTION REQUIREMENTS FOR ALL MACHINES | All
radial and axial clearances are checked against their original values. | Casings, shells and frames/diffusers are inspected for cracks and erosion. | Compressor inlet and compressor flowpath are inspected for fouling, erosion, corrosion and leakage. | The IGVs are inspected, looking for corrosion, bushing wear and vane cracking.
TYPICAL MAJOR INSPECTION REQUIREMENTS FOR ALL MACHINES | Rotor
and stator compressor blades are checked for tip clearance, rubs, impact damage, corrosion pitting, bowing and cracking. | Turbine stationary shrouds are checked for clearance, erosion, rubbing, cracking, and build-up. | Seals and hook fits of turbine nozzles and diaphragms are inspected for rubs, erosion or thermal deterioration.
TYPICAL MAJOR INSPECTION REQUIREMENTS FOR ALL MACHINES Bearing liners and seals are inspected for clearance and wear. | Inlet systems are inspected for corrosion, cracked silencers and loose parts. | Exhaust systems are inspected for cracks, broken silencer panels or insulation panels. | Check alignment – gas turbine to generator/gas turbine to accessory gear. |
TYPICAL MAJOR INSPECTION REQUIREMENTS FOR ALL MACHINES Turbine buckets are removed and a nondestructive check of buckets is performed (first stage bucket protective coating should be evaluated for remaining coating life). | Buckets that were not recoated at the hot gas path inspection should be replaced. |
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THE END
BEST WISHES 461
