Gas turbine control system Control of gas turbine is done by Control of gas turbine is done by Startup control Startup control Acceleration control Acceleration control Speed control Speed control Temperature control Temperature control Shut down control Shut down control Manual controlManual control

How to determine operating condi How to determine operating conditiontion

The sensors ,( detected turbine spe ed, exhaust thermocouple ,compre ssor discharge pressure,and other

parameter)are used to determine t he operating condition of the gas tu

rbine

Fuel stroke reference (FSR) FSR is the command signal for fuel fl

ow Control of gas turbine is done by the

lowest FSR(FSR SU, FSR ACC ,FSRN, FSRT,FSR SD,FSR MAN)

The lowest FSR value of the six contr ol loop is allowed to fuel control syst

em

Simplify control schematic

Control shem. block diagram

Start up/Shut down sequen ce

and control Start up function objective Start up function objective

Bring the gas turbine from zero speed Bring the gas turbine from zero speed to full speed safely by providing prope to full speed safely by providing prope

r fuel to established flame and acceler r fuel to established flame and acceler ate the turbine safely ate the turbine safely

Minimize the low cycle fatigue of the h Minimize the low cycle fatigue of the h ot gas parts during the sequence ot gas parts during the sequence

Speed detector Speed is the important parameter du

ring start up because the sequence o f start up is the relation of speed

Turbine speed is measured by magn etic pick up

Speed detector sent signal to Mark V to convert electrical signal to be the

turbine speed in percent or rpm.

Speed converter

Speed relay The speed relay that are used to co

ntrol the sequence of start up L14 HR Zero speed L14 HM Minimum speed L14 HA Acceleration speed L14 HS Full speed

L14HR Zero Speed

L14HP Spare speed signal

L14HF At field flashing speed

L14HM Minimum Firing Speed

L14HA Accelerating speed

L14HS Min operating speed

L14HC Auxiliary Cranking Speed Relay

L14HT Cool down Slow Roll Start Speed Relay

006. %031. %

18%19%

95%90%

18%15%

50%4 6 %

964. %948. %

60%50%

84. %32. %

Start up control Operate as an open loop control usi

ng preset level of the fuel comman d signal FSR(Zero , Fire ,Warm up,A

ccelerate,) FSR level are set as control constan

t and calculation in the Mark V

144. %

175. %

306. %

005

5%/s

sss1 Start up FSR

Start up curve

Fire shut down Fire shut down is an improvement o

ver the former fuel shut off at L14 HS drop out by maintaining flam

e down to lower speed to reduction the strain develop on hot gas path

part

-- FSRMAX Max Fuel Reference

L83 -- SDSET Preset FSRSD to Existing FSR

L83 -- SDMIN SetFSRSD to FSRMIN

-- FSR Fuel Stroke Reference %

-- FSRMIN FSR: Minimum %

-- FSKSDn ShutdownFSR Ramp n

L83 -- JSDn Set FSRSD Ramp Rate to FSKSDn

L83 -- SDL FSRSD Lower Logic

L83 -- SDR FSRSD Raise Logic

-- FSRMIN FSR: Minimum %

-- FSKSDB Shutdown FSR Ramp Dead band 01. %

FSRSD -- Shut down FSR Signal %

L60SDM -- FSRSD atMin FSR

100%

L83SDSET

L94 -- SD Shutdownwi thBreaker Open L94 -- SDY T.D. L94SD

L83 -- SDSET Preset FSRSD to Existing FSR

025. s

L83SDMIN

L83 -- SDMI N Set FSRSDtoFSRMI NL60 -- SDM FSRSDat Mi nFSR

L28 -- CAN Any Can Flamed Out L83 -- RB Ramp to BlowoutSelectedL94 -- SD Shutdownwi thBreaker OpenL 4 -- Master protective signal

FSR Shut down ramp rate

01. %/sec

5%/sec

005. %/sec

01. %/sec

1%/sec

01. %/sec

01. %

L83JSD1

L94 -- X Turbine ShutdownL83 -- SDR FSRSDRai se Logi c L 4 -- Master protective signal

L83JSD1 -- SetFSRSDRampRate toFSKSD1

L83SDL FSR Lower logic

- L- L6060 - SDM logic false when FSRSD FSRMIN - SDM logic false when FSRSD FSRMIN >0 .1 % >0 .1 %- L- L8383 RB logic true when Flame out RB logic true when Flame out 1>1> sec sec or Flame ON but TNH or Flame ON but TNH 30< %30< %

LL8383 SDL will be logic true in the case of below SDL will be logic true in the case of below

- One can out(L- One can out(L2828CAN)CAN)

L83JSD2 to 5 logic

Flame ONTNH 30< %

- FSRSDFSRMI N- FSRSDFSRMI N > 0 .1 % > 0 .1 %

GT. Trip

1 Can off

Speed control The speed control system control the sp

eed and load of the gas turbine to maint ain speed at100% at any load

Speed control software will change FSR in proportion to the difference between

TNH(turbine speed)and TNR(speed ref.) Turbine drive generator operating spee

d range normally from -95% 107% Start up reference speed is1003. %

Speed droop Droop speed control is the proporti

onal control changing the FSR in pr oportion to the difference between

actual turbine speed and turbine sp eed reference as the equation belo

w - (TNR TNH)x Droop gain+FSRNL =F

SRN

Droop control algorithm

100%

147. %

1sec

105

Droop control curve

Synchronizing control TNR for synchronizing is1003

% to keep the generator faster than the grid

If frequency has varied enough the speed matching circuit adjust TNR t

o maintain turbine speed02 to 04. % faster than the grid

Turbine speed reference TNR

Speed control schematic

Auto synch logic

Synch permissive logic109%865. %

109%865. %

505

495. Hz

505. Hz

495. Hz

System line voltage

Generator volts

Generator frequency

Line Frequency

Synch speed matching permissive

Auto synch permissive logic

Temperature control The temperature control system will lim

it fuel flow to gas turbine to maintain int ernal operating temperature within gas

turbine limitation of turbine hot gas pat h parts.

Firing temperature is the temperature e xists at first stage nozzle. This temperat

ure must be limited by control system

Firing temperature It is impractical to measure temperature

direct to the combustion chamber or at t he turbine inlet So, the control system c

ontrol the exhaust temperature instead. Firing temperature as a function of fuel

flow (FSR) FSR temp. control curve are used as bac

k up to primary CPD. Bias temp.

Exhaust temperature control 1818 Chr omel al umel TC ar e i nst al l Chr omel al umel TC ar e i nst al l

ed at exhaust pl enumt o sent si gnal ed at exhaust pl enumt o sent si gnal t o Mar k V t o Mar k V

Exhaust t emper at ur e cont r ol sof t war e

11 Temper at ur e cont r ol command Temper at ur e cont r ol command 2.2. Temp control bias calculation Temp control bias calculation 3.3. Temp r ef er ence sel ect i on Temp r ef er ence sel ect i on

Temperature control FSR.

Exhaust temp control command Is the temperature control command (TT

RXB)compare the exhaust temperature c ontrol set point(TTXM).The soft ware pro

gram converts the temperature error to f uel stroke reference signal FSRT

Temperature control bias Firing temperature limit by linearized

function of exhaust temperature and CPD backed up by linearized function

of exhaust temperature and FSR

Temperature control Bias

Isothermal Isothermal

Exha

ust t

empe

ratu

re

(TX)

Exha

ust t

empe

ratu

re

(TX)

Constant firing temp

(liberalized)

Constant firing temp

(liberalized)

Compressor discharge pressure(CPD) Fuel stroke reference(FSR)

Temperature control bias

Temperature control bias FF F FF FF F . . .

If CPD bias >FSR bias Alarm will show

GT.Operate by heavy oil(monitor no zzle plugging)

if FSR bias >CPD bias alarm will show

CPD & FSR bias temp control

Temperature reference select program

For temperature reference select,th ree digital input signal are decode (

L83 J TN) t o sel ect one set of co nstant 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 select

Temperature reference select program

Fuel control system Fuel control system will change fuel

flow to the combustion in response to the fuel stroke reference signal(F

SR) FSRFSR11 call for liquid fuel flow call for liquid fuel flow FSR2 call for gas fuel flow FSR = FSR FSR = FSR11 + FSR + FSR22

Liquid fuel control system

Liquid fuel bypass servo valve

Liquid fuel control system When liquid fuel is selected and start. The

control system will check L4 logic(1). At minimum speed L20FLX(FO. trip valve) and L20CF(fuel oil clutch) will energized.

When GT. Firing FSRSU will go to control turbine through fuel splitter and liquid fuel flow command FQROUT will demand to fuel oil by pass valve to control liquid fuel flow to combustion chamber.

Liquid fuel flow diagram

Min sel

FSRSUFSRSDFSRTFSRNFSRMAN

FuelSplitter

Fuel flowCom-mand

BypassServoCom-mand

Servo valve

FSR FSR1 FQROUT DCmA

Liquid fuel flow control

FSR1V1 Fuel splitter

Fuel change permissive

Fuel Split Transfer Rate 3.3 %SP/s

Fraction of Liq Fuel Set point Command

Increase Liquid FuelIncrease Gas Fuel

Fuel Stroke Reference Fuel Splitter Liquid Fuel Purge Level

Fuel Splitter Gas Fuel Purge Level

Fraction of Liquid Fuel

Mixed Fuel Operation

Completely on Gas Fuel

Completely on Liquid Fuel

Liquid Fuel Stroke Ref from Fuel Splitter

Gas Fuel Stroke Ref from Fuel Splitter

0.5 %

0.5 %

Liquid Fuel Stop Valve Control Signal

Flow divider mag pickup speed

Liq fuel bypass valve servo current

Liquid Fuel Stroke Ref from Fuel Splitter %

Turbine Speed %

Master protective signalCalibration position reference %

Calib selection command pass code

Excessive Liq Fuel Startup 8.5 %

Liq Fuel Bypass Valve Flow Detection Trouble Set point 3 %

LF. Byp. Vlv. Servo CurrentTrouble Alarm 30 %

10 secMaster reset

Liq Fuel Bypass Valve Flow Detected Trouble Alarm

Liquid Fuel Flow High (trip )

Liq Fuel Flow Reference Angle %

Liquid fuel bypass valve servo command[65FP-1]

ALM171:'LIQUID FUEL CONTROL FAULT'

System check from flow divider and servo valve

Excessive flow on start up (trip GT. If excessive flow exist during warm up period) L60FFLH

LVDT. Position feed back Bypass valve is not fully open

when stop valve is close Loss of flow divider feed back

Fuel gas control system Fuel gas flow is controlled by the gas

speed ratio stop valve (SRV) and Gas control valve (GCV)

SRV is designed to maintain a predetermined pressure(P2)at the inlet of gas control valve as a function of gas turbine speed

GCV plug is intended to be proportional to FSR2 for fuel gas flow

GVC & SRV control block GVC & SRV control block diagramdiagram

Min sel

FSRSUFSRSDFSRTFSRNFSRMAN

FuelSplitter

GCV.Com-mand

GasServoCom-mand

Servo valve96GC

FSR FSR2 FSROUT DCmA

SRV.Com-mand

SRV.ServoCom-mand

Servo valve90SR

FPRGOUTDCmA

FG. Flow Control

FG. Press Control

GCV. Schematic diagram

Gas control valve out put

Gas Fuel Stroke Ref from Fuel Splitter GCV servo command

[65GC-1] %

Calibration position reference %

Calibration selection command pass code

Gas Fuel Stop Valve Open

Master protective signal

SRV. SchematicTurbine Speed

Gas Ratio Valve OpenMaster protective

SRV. Out put signal

Fuel Gas Press Ratio Control Gain 3.5146 psi/%

Fuel Gas Press Ratio Control Offset -17.88 psi

Stop/Speed Ratio Valve Shutdown Command Set point

-40 psi

Gas Ratio Valve Control Press Ref psi

Stop/speed ratio valve servo command [90SR-1 ] psi

Gas Ratio Valve Control Press Ref (psi)

Fuel gas control and monitor alarm

Excessive fuel flow during start up Loss of LVDT f eed back on SRV and GC

V Servocur r ent t o SRV. det ect ed pr i or t o p

ermissive to open Servo current to GCV. detected prior t

o permissive to open I nt er val ve pr essur e l ow

s ss sssssss sssss servo current %

ssssssss sssss sss - controlvalve [96GC 1]

%

Gas Fuel Stroke Ref from Fuel Splitter %

Position fdbck gas controlvalve - [96GC 1]

% 3 %

sss3

5% 5 sec

Gas control valve not following reference

Gas control valve not following reference trip

Gas Control Valve Position Feedback Fault

Gas Control Valve Open Trouble Alarm

Gas Control Valve Servo Current Fault

ALM1 3 3 :'GASCONTROL VALVE SERVO TROUBLE'

- 5%

5%

375. %

Gas Fuel Stop Valve Open 3 sec

COMMAND PB Master reset

Speed ratio valve servo current %

ssssssssss ssss sss sssss - sss[ 9 6 2 ]

Position fdbck srv - 96 1[ SR ] %

ALM1 3 4 :'GASFUEL INTERVALVE PRESSURE TROUBLE'

Gas Ratio Valve Open

Stop/Ratio Valve Position FeedbackTrouble Alarm Lo

ALM1 3 2 :'GASRATIO VALVE POSITION SERVO TROUBLE'

Stop/Ratio Valve Open Trouble Alarm

Stop/Ratio Valve Servo Current Trouble Alarm

Startup Gas Fuel Stroke High

COMMAND PB Master reset

-5 sss

2 sss

- 6 .6 7 %

667. %

1 5 %

333. %

Dual fuel control Gas turbine are designed to operate b

y both FG & FO. The control has provid e t he f ol l owi ng f eat ur e

Tr ansf er f r omone f uel t o anot her Al l owt i me f or fi l l i ng t he l i ne Mi x f uel oper at i on operationof l i qui d f uel nozzl e pur ge when op

erating totally on Gas fuel.

Fuel splitter schematic

Fuel transfer

Mix Fuel operation Limit on the fuel mixture are requir

ed to ensure Proper combustion Liquid fuel distribution Liquid fuel flow velocity Combustion ratio

Fuel transfer limit (For GE.9 E) Transfer(select one fuel)prior to start

up Do not transfer fuel below30 MW. Do not operate mix below30 rat

ed gas flow or 60% gas at30MW.(t o avoid nozzle pressure ratio droppin g below 1 .2 5 and possibly causin g combustion chamber pulsation.)

Fuel transfer limit (For GE.9

Do not mixed below10% rated li quid flow(to avoid excessive liquid f

uel recalculation flow resulting in fu el over heating and possibly causin g fuel oil pump damage.)

Mix fuel Allowable range curve

30 MW

0100

3070

6040

9010

100 0

% GAS % LIQ

NoMIX

NO MIXED

NOMIXED

MWLOAD

Rated

MIXED OK

Modulate Inlet Guide Vane Pr ot ect compr essor pul sat i on by m

odulate during the acceleration of ga s turbine to rated speed.

I GV modul at i on mai nt ai n pr oper fl ow and pressure to combustion.

Maintain high exhaust temperature at low load when combined cycle ap

plication.

Modulate IGV control scheme.

IGV. Control control reference (CSRGV)

MINSEL

IGV part

Speed

MAXSELIGV

MAN

IGVTEMPCONTROL

XMINSEL

L83GVMAX

86 DGA

CPD.

TNH.

CSRGV

57 DGA

CLOSE

OPEN

L83GVMANTTRX

L8 3 GVSS371 s1120 s

TTXM

(IGV CONTROL REFERENCE)

CSRGVX+

VIGV Temp Control Airflow Ref Offset

Turb inlet guide vane servo vlv command [90TV-1] DGA

IGV. Control Algorithm from Mark V IGV. Control Algorithm from Mark V

IGVPart speed control

86 DGA CPRS. OFF Line washing

VIGV. Reference Angle (DGA)

57 DGA

57 DGAPermissive Inlet Guide Vane Ref

IGVManual Control Permissive

0 DGAStator 17 IGV Gain

1 DGA/%

Airflow Control Reference % IGV on Temperature Control

IGV at Minimum Position

IGV at Maximum Position

Temp Control and Manual Control Ref

Calibration selection command pass code

Calibration position reference %

IGV. Part speed reference

Speed Correction Factor Compressor Temperature Ratio

519 o F

Open IGV Position 86 DGA

VIGV Part Speed HP Corr Speed Offset %

77320. %

VIGV Part Speed HP Corr Speed Gain

VIGV Part Speed Ref MinSetpoint

Part Speed VIGV Reference

Max Comp InletFlange Temp o F

HP Turbine Speed %

6786. DGA/%

Turbine Speed HP, Iso Corrected

34 DGA

IGV. Control control reference (CSRGV)

MINSEL

IGV part

Speed

MAXSELIGV

MAN

IGVTEMPCONTROL

XMINSEL

L83GVMAX

86 DGA

CPD.

TNH.

CSRGV

57 DGA

CLOSE

OPEN

L83GVMANTTRX

L8 3 GVSS371 s1120 s

TTXM

(IGV CONTROL REFERENCE)

CSRGVX+

From Where ?

CSRGVX

L83GVMAN_CMD

MinSEL

X

X

XX X

T V = OUT

1+TS V

RESET OUT =V

IGVMAN

TTXM

TTRX

CSKGVDB

L83GVDB

TTRXGVB

700 F

2048 F

L83GVSS

TNGV

CSKGVTPG

CSKGVTC

CSRGV

CSRGVX

2 deg F

2 deg F

4 sec

TTRX

MEDSEL

XX

Z-1

L83REC

TTRXC

TTRXR1

TTRXR2

TTRMINSEL

TTRX

1.5 F/sec

-1 F/sec

IGV Temperature control (CSRGVX) Bias by FSR. , CPD.

L83JTN = Temperature select logic(by damper&fuel)N = 0 Operate open cycle mode on Gas fuel N = 1 Operate Combined cycle mode on Gas fuel N = 2 Operate open cycle on mode Liquid fuel N = 3 Operate Combined cycle mode on Liquid fuelFor example show value of curve N= 1

X X X

X X X

+

+

+

+

AA < BB

L60TRFFSR

Conner

Slope

ISO thermal

Slope

CPD

Conner

L83JTN

MINSEL

TTRMINSEL42.707 %

4.987 F/%

1140 deg F

8.058 prs_R

27.342 F/ prs

IGV. Operation curve

IGV. Fault detection Position feedback

IGV -96 1[ TV ]

31DGA

35 DGA

-30 %

IGVControl Permissive5 sss

COMMAND PB Master reset

- IGV Loss ofFeedback Alarm

- IGV Vanes Open Alarm

- IGV Servo CurrentAlarm - Neg. Saturation

- - TCQA REG CUR IGV control servo current

DGA

%

IGV. Not following CSRGV.

Position feedback IGV - 96 1[ TV ] DGA

VIGV Reference Angle DGA ALM1 0 8 : 'INLET GUIDE VANE CONTROL TROUBLE ALARM'

IGVNotFollowingCSRGVTrip

75 DGA

5 SEC

75 DGA

5 SEC