Gas Turbine Gas Turbine Control & Protection Control & Protection

SystemsSystemsby David Lucier

PAL Engineering

Control SystemsControl Systems

What must be What must be ““controlledcontrolled””

on on GEGE gas turbines?gas turbines?

Turbine Shaft SpeedTurbine Shaft SpeedRate of Change of Speed Rate of Change of Speed

(a.k.a. Shaft Acceleration)

Exhaust TemperatureExhaust TemperatureRate of Change of TemperatureRate of Change of Temperature

Air Flow through CompressorAir Flow through Compressor

TNH units: RPM or % speedTNH units: RPM or % speedAcceleration: RPM/second or

% speed/second

TTX units: TTX units: Degrees Fahrenheit (Degrees Fahrenheit (˚̊F )F )Exhaust Temperature Rate: ˚F per second

Airflow: lbsAirflow: lbs--air per hourair per hour(actual flow not measured)

What devices What devices do the controlling?do the controlling?

Liquid Fuel Bypass ValveLiquid Fuel Bypass Valve

Gas Stop Speed/Ratio ValveGas Stop Speed/Ratio ValveGas Control ValveGas Control Valve

Variable Inlet Guide VanesVariable Inlet Guide Vanes

Modern GE Modern GE Control SystemsControl Systems

Mark IV Control Panel, TMRMark IV Control Panel, TMR(1982 (1982 –– 1989 Era)1989 Era)

<R><R>

<S><S>

<T><T>

Mark IV Operator PanelMark IV Operator Panel

Mark IV ScreenMark IV Screen

Mark V Control Panel, TMRMark V Control Panel, TMR(1989 (1989 –– 2000 Era)2000 Era)

Human Machine InterfaceHuman Machine InterfaceOriginal <I> versus New <HMI>Original <I> versus New <HMI>

Human Machine InterfaceHuman Machine Interface(Close(Close--up of HMI Main Screen)up of HMI Main Screen)

TypicalTypical HMI HMI ScreensScreens(Mark V)(Mark V)

Control PrinciplesControl Principles

Minimum Value Select:Minimum Value Select:

The control subThe control sub--systemsystem““calling forcalling for”” the the leastleast fuel flow fuel flow

will be in command.will be in command.

SimplifiedSimplifiedMinimum Value SelectMinimum Value Select

(18) TC(18) TC’’ss

%TNH%TNH

FSR FSR LimitsLimits

%TNH/sec%TNH/sec

TTXMTTXM

Min & Max Value GatesMin & Max Value Gates

MIN (6 inputs)MIN (6 inputs)

MINMIN

MAXMAX

Liquid Fuel Bypass Valve, Liquid Fuel Bypass Valve, BPV

Gas Stop Speed/Ratio Valve,Gas Stop Speed/Ratio Valve, SRVGas Control Valve, Gas Control Valve, GCV

Variable Inlet Guide Vanes, Variable Inlet Guide Vanes, IGV

Triple Modular Redundant (Triple Modular Redundant (TMRTMR) ) (Speedtronic(Speedtronic™™ Mark IV thru VI)Mark IV thru VI)

> BPV> BPV> SRV> SRV> GCV> GCV> IGV> IGV

TMRTMR

<R><R>

<S><S>

<T><T>

Temperature Profile DiagramTemperature Profile Diagram(Base Load Operation)(Base Load Operation)

3000 ˚F

< Tf = 2020 ˚F

TTX = 1000 ˚F

< 500 ˚F59˚F< 45˚F

< Te

mpe

ratu

re >

solid line graph >solid line graph >

INLETINLET EXHAUSTEXHAUST

Pressure Profile DiagramPressure Profile Diagram(Base Load Operation)(Base Load Operation)

150 psia > < 149 psia

14.7 psia14.7psia

14.3 psia

< Pressu

re >

dotted line graph >dotted line graph >

INLETINLET EXHAUSTEXHAUST

Gas Turbine StartGas Turbine Start--up Curvesup Curves

%TNH

Fuel Stroke Ref, FSR

TTX = 900˚F >

26%

19.5%

TTX = 550 ˚FSpee

d

Exh. T

emp

Speed

Fuel Stroke ReferenceFuel Stroke Reference(FSR constants for Start(FSR constants for Start--up)up)

% F

SR >

>

TIME, Seconds > >

Start-up FSR Algorithms

Constants ListConstants List

Liquid Fuel Liquid Fuel Control PrinciplesControl Principles

Fuel Control PrinciplesFuel Control Principles

Fuel Flow is proportional to:Bypass Valve Position

&

Fuel Pump Speed

FFN = ƒ (%FSR) x ( %TNH)

Liquid Fuel FlowLiquid Fuel Flow

TNH measured 0 to 100 % speed

FFN measured in frequency(measure speed of flow divider)

FSR measured 0 to 100 percentof Bypass Valve (full open to closed)

FFN = ƒ (%FSR) x ( %TNH)

Liquid Fuel Flow PrinciplesLiquid Fuel Flow Principles

Fuel Pump is driven by Turbine through Accessory Gear Box (% TNH)

By-pass Valve Position is controlled by Speedtronic™ Panel (% FSR)

Flow divider speed is proportional to fuel flow (FFN, gal/min)

Liquid Fuel Control FundamentalsLiquid Fuel Control FundamentalsFFN = ƒ (%FSR) x ( %TNH)

%FSR > < %TNH

< FFN< FFN 70.7 cps/gpm

-- -- -->> -- -- -->> -- -- -->>-- -- -- >>< < -- -- -- -- -- -- >>

-- ---- >>

Roper Liquid Fuel Pump Roper Liquid Fuel Pump & Bypass Valve& Bypass Valve

< < << < << < << < <

> > >> > >

> > >> > >

<< Fuel Bypass Valve<< Fuel Bypass Valve

> > >> > >

> > >> > >

IMO Liquid Fuel PumpIMO Liquid Fuel Pump

Screw PumpScrew Pump

Liquid Fuel Bypass ValveLiquid Fuel Bypass Valve

Servovalve 65FP >Servovalve 65FP >BypassBypassValveValve

Flow Divider Flow Divider Speed Pickup (Speed Pickup (77FN77FN--11))

77FN77FN--1 >1 >

Flow DividerFlow Divider

Flow Divider Flow Divider Speed Pickups (Speed Pickups (77FN77FN--2, 32, 3))

77FN77FN--2, 3 > >

2, 3 > >

Flow Divider Characteristic:

60-tooth wheel4600 cps = 65 gallons/min

Therefore, 70.7 cps per 1.0 gpm

Liquid Fuel Flow CalibrationLiquid Fuel Flow Calibration(from GE Control Specifications)(from GE Control Specifications)

Fuel Flow = .0085 (%FSR) x (%TNH)

1. Assume for “firing” fuel:%FSR = 14%TNH = 16

Firing Fuel = .0085 (14) (19)

Firing Fuel Flow Rate = 1.90 gpm

Liquid Fuel Flow CalibrationLiquid Fuel Flow Calibration(from GE Control Specifications, ISO conditions)(from GE Control Specifications, ISO conditions)

Fuel Flow = .0085 (%FSR) x (%TNH)

2. Assume for “full speed/no load” fuel:%FSR = 14

%TNH = 100Firing Fuel = .0085 (14) (100)

FSNL Flow Rate = 12.0 gpm

Liquid Fuel Flow CalibrationLiquid Fuel Flow Calibration(GE Control Specs, ISO conditions)(GE Control Specs, ISO conditions)

Fuel Flow = .0085 (%FSR) (%TNH)

3. Assume for Base Load Operation:%FSR = 66.6%TNH = 100

Firing Fuel = .0085 (66.6) (100)

Base Load Flow Rate = 57.2 gpm

Liquid Fuel Flow CalibrationLiquid Fuel Flow Calibration(GE Control Specs, ISO conditions)(GE Control Specs, ISO conditions)

Gas Fuel Gas Fuel Control PrinciplesControl Principles

Gas Stop Speed/Ratio & Control ValveGas Stop Speed/Ratio & Control Valve

Gas Fuel Control FundamentalsGas Fuel Control Fundamentals

P2P2P1P1 P3P3

Gas Fuel Pressure GagesGas Fuel Pressure Gages

P1P1 P2P2 P3P3

Gas Stop Speed/Ratio (Gas Stop Speed/Ratio (SRVSRV))& Gas Control Valve (& Gas Control Valve (GCVGCV))

< SRV< SRV

GCV >GCV >

P2 Pressure TransmitterP2 Pressure Transmitter((96FG96FG) )

P2, Pressure Transducer > >P2, Pressure Transducer > >

P1P1

Gas Stop Speed/Ratio (Gas Stop Speed/Ratio (SRVSRV))& Control Valve (& Control Valve (GCVGCV))

< SRV< SRV

GCV >GCV >

< 90SR< 90SR < 65GC< 65GC

Servovalves

Speed/Ratio Valve CalibrationSpeed/Ratio Valve Calibration(from GE Control Specifications)(from GE Control Specifications)

P2 = Speed Ratio (% TNH% TNH) – Preset

P2 = .49 ((%TNH%TNH) – .50 P2 in DC volts

P2P2

Speed/Ratio Valve CalibrationSpeed/Ratio Valve Calibration

P2 = Speed Ratio (% TNH% TNH) – Preset

96FG transducer calibration 96FG transducer calibration 0 to 5.0 DC volts = 0 to 300 psig0 to 5.0 DC volts = 0 to 300 psig

P2 = 2.95 (%TNH) – 30 in psig

Speed/Ratio Valve CalibrationSpeed/Ratio Valve Calibration(from GE Control Specifications)(from GE Control Specifications)

P2 = 2.95 (%TNH) – 30 in psig

At 100% shaft speedAt 100% shaft speedP2 = 265psig, constant

P2P2

Inlet Guide Vane Inlet Guide Vane Control PrinciplesControl Principles

Variable Inlet Guide VanesVariable Inlet Guide Vanes((VIGVVIGV))

Inlet Guide Vane

IGV Actuator & Position IndicatorIGV Actuator & Position Indicator

< IG

V A

ctua

tor >

< IG

V A

ctua

tor >

IGV Angle >IGV Angle >

IGV Control FundamentalsIGV Control Fundamentals

Servovalve 90TV >

< < < < LVDT,

96TV-1, 2, 2

IGV Control IGV Control (Control air flow into compressor)(Control air flow into compressor)

Servovalve 90TV >

RVDTRVDT

20TV >

< <

IGV

Mod

ulat

ing

> >

< <

IGV

Mod

ulat

ing

> >

Summary of Summary of Control PrinciplesControl Principles

Summary of Control SystemsSummary of Control Systems(System calling for (System calling for ““leastleast”” fuel controls FSR)fuel controls FSR)

MVGMVG

< 6 Input Signals

< 6 Input Signals

FSRFSR

Min FuelMin Fuel

Protection SystemsProtection Systems

Four Primary Protections:

OverspeedOvertemperatureLoss of FlameVibration

Four Primary Protections (typical settings):

Electronic Overspeed: 110 % TNHMechanical Overspeed: 112% TNH

Overtemperature (~ 1000 ˚F)

Loss of Flame

Vibration (1 inch/second, 5 mils peak-peak)

Triple Modular Redundant (Triple Modular Redundant (TMRTMR) ) (Speedtronic(Speedtronic™™ Mark IV & V)Mark IV & V)

> BPV> GCV> SRV> IGV

TMRTMR

Logic “0” or “1”

<R><R>

<S><S>

<T><T>

2/3 Voting

Many Secondary Protections including:

Low Lube Oil PressureHigh Lube Oil Header TemperatureLow Hydraulic PressureGenerator LockoutsCustomer Added ProtectionsOther, as required

Protection SystemsProtection Systems(High(High--pressure Hydraulics)pressure Hydraulics)

1200 psig25 psig

L 4 “trips” >

Protection SystemsProtection Systems(20 FG energize to run, de(20 FG energize to run, de--energize to trip)energize to trip)

Solenoid ValveDeenergizes !

< Stop ValveCloses ! !

< L 4 “trips”

1200 psig

Redundancy by AssociationRedundancy by Association(Control & Protection Systems)(Control & Protection Systems)

If operating on Liquid Fuel:

when stop valve closes, the bypass valves goes to

“full recirculation.”

Protection SystemsProtection Systems(If a trip occurs, BPV goes (If a trip occurs, BPV goes to 100% fuel recirculation)to 100% fuel recirculation)

< < < <

< < < <

> > > >> > > >

100 %

fuel

recirc

ulation

>

Stop Valve Closes >

> > > >

Flow Divider Stops

[zero flow]

Redundancy by AssociationRedundancy by Association(Control & Protection Systems)(Control & Protection Systems)

If operating on Gas Fuel:

when stop valve closes, gas control valve also closes

immediately.

Protection SystemsProtection Systems(If a trip occurs, both valves close)(If a trip occurs, both valves close)

Close >>>

Close >>>

Redundancy by AssociationRedundancy by Association(Control & Protection Systems)(Control & Protection Systems)

Inlet Guide Vanes:

When a trip occurs, IGV go toward the “closed” position immediately

to prevent compressor surge.

Protection SystemsProtection Systems(If a trip occurs, IGV Close)(If a trip occurs, IGV Close)

20TVde-energizes >

< < < IGV

Close

RVDT

SummarySummary(Control & Protection Systems)(Control & Protection Systems)

• Shaft Speed Control• Shaft Acceleration Control

• Overspeed Protection

• Exhaust Temperature• Rate of change of Temperature

• Overtemperature Protection

• Vibration• Loss of Flame

• All Other Protective Devices

The EndThe End

Thank you for Thank you for your attention!your attention!

Questions ?Questions ?