Gas Turbine Control

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Cas turbine control system Control of gas turbine is done by Control of gas turbine is done by&tartup control &tartup control Acceleration control Acceleration control&peed control &peed control Temperature control Temperature control&ut down control &ut down control Nanual control Nanual controlow to determine operating condition ow to determine operating condition Te sensors ,( detected turbine speed, exaust termocouple ,compressor discarge pressure,and oter parameter)are used to determine te operating condition of te gas turbineuel stroke reference (&%)&% is te command signal for fuel flow Control of gas turbine is done by te lowest &%(&% &, &% ACC ,&%!, &%T,&% &,&% NA!) Te lowest &% value of te six control loop is allowed to fuel control system&implify control scematicControl sem. block diagram&tart up/&ut down sequenceand control&tart up function objective &tart up function objective Bring te gas turbine from zero speedBring te gas turbine from zero speed to full speed safely by providing properto full speed safely by providing proper fuel to establised flame and acceleratefuel to establised flame and accelerate te turbine safely te turbine safely Ninimize te low cycle fatigue of teNinimize te low cycle fatigue of te ot gas parts during te sequence ot gas parts during te sequence&peed detector&peed is te important parameter during start up because te sequence of start up is te relation of speed Turbine speed is measured by magnetic pick up&peed detector sent signal to Nark v to convert electrical signal to be te turbine speed in percent or rpm.&peed converter&peed relay Te speed relay tat are used to control te sequence of start up L% Zero speed LN Ninimum speed LA Acceleration speed L& ull speed L14HR Zero SpeedL14HP Spare speed signaIL14HFAt fieId fIashing speedL14HMMinimum Firing SpeedL14HA AcceIerating speedL14HSMin operating speedL14HCAuxiIiary Cranking Speed ReIayL14HTCooI down SIow RoII Start Speed ReIay0.06 %0.31%18%19%95%90%18%15%50%46%96.4%94.8%60%50%8.4%3.2%&tart up control Operate as an open loop control using preset level of te fuel command signal &%(Zero , ire ,Warm up,Accelerate,)&% level are set as control constant and calculation in te Nark v14.4%17.5%30.6%005s5s1 secStart up FSR&tart up curveTe image cannot be displayed. Your computer may not ave enoug memory to open te image, or te image may ave been corrupted. %estart your computer, and ten open te file again. !f te red x still appears, you may ave to delete te image and ten insert it again.ire sut downire sut down is an improvement over te former fuel sut off at L& drop out by maintaining flame down to lower speed to reduction te strain develop on ot gas pat partFSRNAX Nax Fuel ReferenceL83SDSET Preset FSRSD to Existing FSRL83SDN!N Set FSRSD to FSRN!NFSR Fuel Stroke Reference FSRN!N FSR:Ninimum FSKSDn Shutdown FSR Ramp nL83]SDn Set FSRSD RampRate to FSK SDnL83SDL FSRSD Lower LogicL83SDR FSRSD Raise LogicFSRN!N FSR:Ninimum FSKSDB Shutdown FSR RampDead band0.1%FSRSD ShutdownFSR Signal L60SDN FSRSDat Nin FSR100 %L&&TL94SD Shutdown with Breaker OpenL94SDY TD L94SDL83SDSET Preset FSRSD to Existing FSR025 sL&N!!L83SDN!N Set FSRSD to FSRN!NL60SDN FSRSD at Nin FSRL28CAN Any Can Flamed OutL83RB Ramp to Blowout SelectedL94SD Shutdown with Breaker OpenL4 Naster protective signal&% &ut down ramp rate01 sec5 sec005 sec01 sec1 sec01 sec0.1 %L]&L94X Turbine ShutdownL83SDR FSRSD Raise LogicL4 Naster protective signal L83]SD1 Set FSRSD Ramp Rate to FSK SD1L&L &% Lower logic L L &N logic false wen &%& &N logic false wen &%&&%N!! > &%N!! > L L %B logic true wen lame out > %B logic true wen lame out > sec secor lame O! but T! < or lame O! but T! 00..11 % %CT Trip1 Can off&peed control Te speed control system control te speed and load of te gas turbine to maintain speed atat any load&peed control software will cange &% in proportion to te difference between T!(turbine speed)and T!%(speed ref.) Turbine drive generator operating speed range normally from &tart up reference speed is &peed drooproop speed control is te proportional control canging te &% in proportion to te difference between actual turbine speed and turbine speed reference as te equation below (T!%T!)x roop gain+&%!L =&%!roop control algoritm100 %14.7 %1sec10.5roop control curve&yncronizing control T!% for syncronizing is . to keep te generator faster tan te grid !f frequency as varied enoug te speed matcing circuit adjust T!% to maintain turbine speed .to . faster tan te gridTurbine speed reference T!%&peed control scematicAuto sync logic&ync permissive logic109%86.5%109%86.5%505Hz495Hz505Hz495HzSystem Iine voItageGenerator voItsGeneratorfrequencyLine Frequency&ync speed matcing permissiveAuto sync permissive logicTemperature control Te temperature control system will limit fuel flow to gas turbine to maintain internal operating temperature witin gas turbine limitation of turbine ot gas pat parts.iring temperature is te temperature exists at first stage nozzle. Tis temperature must be limited by control systemiring temperature !t is impractical to measure temperature direct to te combustion camber or at te turbine inlet &o, te control system control te exaust temperature instead.iring temperature as a function of fuel flow (&%)&% temp. control curve are used as back up to primary CP. Bias temp.xaust temperature control Cromel alumel TC are installed atCromel alumel TC are installed at exaust plenum to sent signal to Nark v exaust plenum to sent signal to Nark vxaust temperature control soft ware.Temperature control command .Temperature control command.Temp control bias calculation .Temp control bias calculation.Temp reference selection .Temp reference selectionTemperature control &%.xaust temp control command!s te temperature control command (TT%B)compare te exaust temperature control set point(TTN).Te soft ware program converts te temperature error to fuel stroke reference signal &%TTemperature control bias iring temperature limit by linearized function of exaust temperature and CP backed up by linearized function of exaust temperature and &%Temperature control Bias!sotermal !sotermal


aust temperature (T



aust temperature (T

)Compressor discarge pressure(CP)uel stroke reference(&%)Temperature control biasTemperature control bias CT. Operate by C. or O.!f CP bias >&% bias Alarm will sow CT.Operate by eavy oil(monitor nozzle plugging) if &% bias >CP bias alarm will sowCP S &% bias temp controlTemperature reference select programor temperature reference select,tree digital input signal are decode (L]T!) to select one set of constant i.e. Base load open cycle select Base load open cycle select Base load combined cycle select Base load combined cycle select Peak load select Peak load selectTemperature reference select programuel control systemuel control system will cange fuel flow to te combustion in response to te fuel stroke reference signal(&%) &% &% call for liquid fuel flow call for liquid fuel flow&%call for gas fuel flow&% = &% =&% &% + &% + &%Liquid fuel control systemLiquid fuel bypass servo valveLiquid fuel control systemWen liquid fuel is selected and start. Te control system will ceck L4 logic(1). At minimum speed L20L(O. trip valve) and L20C(fuel oil clutc) will energized.Wen CT. iring &%& will go to control turbine troug fuel splitter and liquid fuel flow command $%OT will demand to fuel oil by pass valve to control liquid fuel flow to combustion camber.Liquid fuel flow diagramNin selFSRSUFSRSDFSRTFSRNFSRNANFuelSplitterFuelflowCommandBypassServoCommandServovalveFSRFSR1 FOROUTDCmALiquid fuel flow control&%1v1 uel splitterFuel change permissiveFuel Split Transfer Rate33 %SP/sFraction of Liq Fuel Set point Command!ncrease Liquid Fuel!ncrease Cas FuelFuel Stroke ReferenceFuel Splitter Liquid Fuel Purge LevelFuel Splitter Cas Fuel Purge LevelFraction of Liquid FuelNixed Fuel OperationCompletely on Cas FuelCompletely on Liquid FuelLiquid Fuel Stroke Reffrom Fuel SplitterCas Fuel Stroke Reffrom Fuel Splitter0 %0 %Liquid Fuel Stop valve Control SignalFlow divider mag pickup speedLiq fuel bypass valve servo currentLiquid Fuel Stroke Reffrom Fuel Splitter Turbine Speed Naster protective signalCalibration position reference Calib selection command pass codeExcessive Liq Fuel Startup 8 Liq Fuel Bypass valve Flow Detection Trouble Set point3 LF Byp vlv Servo CurrentTrouble Alarm30 10 secNaster resetLiq Fuel Bypass valve Flow Detected Trouble AlarmLiquid Fuel Flow High (trip )Liq Fuel Flow Reference Angle Liquid fuel bypass valve servo command6FP1(ALN171'L!OU!D FUEL CONTROL FAULT'&ystem ceck from flow divider and servo valvexcessive flow on start up (trip CT. !f excessive flow exist during warm up period) L60L LvT. Position feed back Bypass valve is not fully open wen stop valve is close Loss of flow divider feed backuel gas control system uel gas flow is controlled by te gas speed ratio stop valve (&%v) and Cas control valve (CCv) &%v is designed to maintain a predetermined pressure(P2)at te inlet of gas control valve as a function of gas turbine speedCCv plug is intended to be proportional to &%2 for fuel gas flowCvC S &%v controlblock diagram CvC S &%v controlblock diagramNin selFSRSUFSRSDFSRTFSRNFSRNANFuelSplitterCCvCommandCasServoCommandServovalve36CCFSRFSR2 FSROUTDCmASRvCommandSRvServoCommandServovalve30SRFPRCOUTDCmAC. low ControlC. Press ControlCCv. &cematic diagramCas control valve out putCas Fuel Stroke Ref from Fuel SplitterCCv servo command|6CC1]Calibration position reference %Calibration selection command pass codeCas Fuel Stop


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