Protection SystemsProtection Systems Turbine protection system consists of number of sub-

systems which operate during each normal start-up and shutdown Few operate strictly during emergency and abnormal

operating conditions.

Protection systems are set up to Detect and alarm the failure. If the failure is of serious nature, protection system will trip

the turbine.

Protection system responds to: Simple trip signals like

– low lube oil pressure

– high gas compressor discharge pressure etc….

Protection SystemsProtection Systems

More Complex parameters like

– Over speed

– Over temperature

– High Vibration,

– Combustion monitor

– Loss of flame etc…..

To ensure the safety and safe operation of turbine

Speedtronic system is equipped with master control and

protection circuit

Protection SystemsProtection Systems Turbine Protection systems includes:

Trip Oil – Inlet orifice, Check Valves & Orifice network– Pressure switches– Dump valves

Over speed Protection Electronic Over speed trip Over temperature Protection

Over Temperature Protection Over temperature alarm (L30TXA) Over temperature Trip (L86TXT)

Flame Detection and Protection System

Protection SystemsProtection Systems

Vibration Protection High Vibration Alarm & Trip Vibration transducer fault Alarm

Combustion monitoring Spread calculations Exhaust Thermocouple Trouble

Alarm Combustion Trouble Alarm High Exhaust Temperature

Spread Trip Spread monitor enable

MasterProt.

Circuit<RST>

GCV

SRV

RelayVoting

Module

20FG

FUELPUMP

PrimaryOS

Overtemp

Vibration

CombMonitor

SecOS

LossOf

Flame

MasterProt.

Circuit<XYZ>

BypassValveServovalve

RelayVotingModule

20FL

Gas FuelGas FuelControlControl ValveValve

Gas FuelGas FuelSpeed Ratio/Speed Ratio/Stop ValveStop Valve

LiquidLiquidFuel StopFuel StopValveValve

Trip FunctionsTrip Functions

OR

Primary Over speed Detected

Emergency Over speed Detected

Loss Of Speed Signal

Vibration Trip

High Lube Oil Temp Trip

Low Lube Oil Pressure Trip

Low Servo Pressure Trip

Generator Differential Trip

Manual Trip

Customer Trip

Exhaust Over temp Trip

TRIP TURBINE

Compt. Fire Detection Trip

Loss of Flame Trip

Trip Oil protectionTrip Oil protection It is a primary protection interface between the turbine control and

protection system and the components of the turbine which admit or shut-off, fuel.

System devices are electrically operated by Speedtronic control system as well as some totally mechanical devices.

MasterProtection

L4Circuits

20FG

20FL

63HL

Gas FuelSpeed Ratio/Stop Value

OH

Gas Fuel Dump Relay

Valve

63HG

Orifice AndCheck Valve

Network

Protective Signals

RESETManual

Trip

OVERSPEEDTRIP

INLET ORIFICE

Manual Trip(When Provided)

12HA

Liquid Fuel Stop Valve

Gas fuel

LiquidFuel

Over Speed ProtectionOver Speed Protection Electronic Over speed function is

performed in <RST> and <XYZ>. TNH is compared with TNKHOS. When TNH>TNKHOS, turbine is

tripped and latched till Reset. “ELECTRICAL OVERSPEED TRIP”

is displayed in CRT.

TNKHOST

TNHHigh Pressure Over Speed Trip

<RST> <XYZ><RST> <XYZ>

HP Speed

Trip Setpoint

Test

Test Premissive

TNKHOS

LK3HOST

L86MR1 Master ResetReset

SetAnd

Latch

L12H To Master

ProtAnd

AlarmMsg

A A>BB

ManualReset

ManualTrip

12HP

OD

Overspeed Bolt

OLT Mechanical Over speed system

Consists of Over speed bolt assembly in accessory

gear box. Over speed trip mechanism in the

accessory gear. Position limit switch 12 HA. Acts as a back-up control Trip setting > Electronic Setting

Over Temperature ProtectionOver Temperature Protection

Protects GT against possible damages against Over firing.

TTXOT3TTXOT3

TTXOT1TTXOT1

TTXOT2TTXOT2

TTXMTTXMOVER-TEMP. TRIP & ALARM.OVER-TEMP. TRIP & ALARM.

TTRXBTTRXB

L86MR1L86MR1

L30TXAL30TXAALARMALARM

To AlarmTo AlarmMessageMessage

And And SpeedSpeed

SetpointSetpointLowerLower

To To Master Master

Prot.Prot.And And

AlarmAlarmMsgMsg

TRIPTRIP IsothermalIsothermal

ALARMALARMA A A>BA>BBB

AA A>BA>BBB

A A A>BA>BBB

SetSetAndAnd

LatchLatch

ResetReset

OORR

TTREF

CPD

CONTROL

25ºF25ºF

40ºF40ºF

ALARM

TRIP

ISO TRIP1090º F

1030ºF

It is a backup protection system, operates only after the failure of temperature control system.

Flame Detection & ProtectionFlame Detection & Protection Speedtronic Mark-V flame detectors perform two functions

One in the Sequencing system other in Protective system

Flame detected by UV radiation. Speedtronic control furnish +350VDC to drive the UV detector

tube. In the presence of UV radiation, the gas in the detector tube ionizes and conducts current.

Speedtronic counts the no.of current pulses/sec through UV sensor.

Typically 300 pulses/sec when strong UV signal is present.

Flame Detection & ProtectionFlame Detection & Protection

TUEBINEPROTECTION

LOGIC

TURBINECONTROL

LOGIC

FLAMEDETECTION

LOGIC

ANALOGI/O

(FlameDetectionChannels)

28FDUV SCANNER

28FDUV SCANNER

28FDUV SCANNER

28FDUV SCANNER

CRTDISPLAY

Speedtronic MK-V Flame Detection

NOTE: Excitation for the sensor and signal processing is performed by SPEEDTRONIC Mk V circuits

<P>

Vibration ProtectionVibration Protection Gas Turbine unit comprises

Several independent vibration channels

Each channel detects excessive vibration by a seismic pickup

Each channel includes one vibration pickup (velocity type) and a Speedtronic Mark-V amplifier circuit.

Vibration detectors generate a relatively low voltage by the relative motion of a permanent magnet suspended in a coil and therefore no excitation is required.

Vibration protection system trips the turbine when vibration level exceeds predetermined level.

A A>BB

A A<BB

L30TEST

A A>BB

OR

AND

RESET

SETAND

LATCH

30V

FAULT

ALARM

TRIP

<RST>

VF

VA

VT

Auto Or Manual Reset

TRIPL39VT

ALARML39VA

FAULTL39VF

Speedtronic control generatesHigh Vibration Trip

Vibration Transducer Fault

Combustion MonitoringCombustion Monitoring Primary function

to reduce the likelihood of extensive damage to the gas turbine if the combustion system deteriorates.

Continuously examines the exhaust temperature and compressor discharge temperature thermocouples

Reliability of combustion monitor depends on condition of exhaust thermocouples.

Several software programs are written to achieve this

<RST><RST>

MedianSelect

CalculateAllowable

Spread

CalculateActual

Spreads

A A>BB

A A>BB

A A>BB

A A>BB

TTXSPL

L60SP2

L60SP3

L60SP4

CTDA

MedianSelect

TTKSPL1

TTKSPL2

TTKSPL5

TTKSPL7

Constants

TTXC

TTXD2

Combustion Monitor Algorithm

L60SP1