GAS TURBINE

PROTECTIONS

Protection System

• Electrical Protection systems>>Over Speed>>High Exhaust Temperature>>Low Lube Oil Pressure>>Low Trip Oil Pressure>>High Lube Oil Temperature>>Loss of Flame>>High Vibration

Protection Systems Contd...>>Combustion Monitoring

>>Customer Trip

>>Fire Detection in Compartment Enclosures

>>Generator Class ‘A’ Trip

Over Temperature Alarm & TripOver Temperature Alarm & Trip

TTXM A A>BB

To Alarm Message & Speed Set Point Lower

A A>BB

A A>BB

OR

LATCHSET

RESET

TTKOT3

ToMaster

TTRX

TTKOT2

L86MR1 ProtectionAlarm &Trip

TTKOT1

Over Temperature Protection

TTXMTemp.Feedback

TRIP

Compressor Pressure Discharge

TTKOT3

TTKOT2

TRIP

ALARM

TTRX(Temp. ControlReference)

Vibration protection

• Standard Vibration Measurements used for Tripping GT are Velocity Type on Bearing Housing

• Alarm setting = 0.5 inches / sec

Trip setting = 1.0 inches / sec

• Total System is Tested for Integrity during Turbine Shut Down by Mark IV / V Panel

Vibration ProtectionIf All Gas Turbine Sensors

are Disabled or Faulty

If All Generator Sensors are are Disabled or Faulty

If 3 or more GT Sensors are Disabled or Faulty

If 2 or more Generator sensors Disabled or faulty

OR

OR

T

T

GROUPDISABLEDALARM &TRIP

STARTINHIBIT

Vibration TripOPTVTD

Any Trip and if any Adj.Pair Disabled or Alarmed

Any Trip and any Alarmfrom other Sensor

Any Trip and if 2 or moreSensors are Disabled

Any Trip and Any Alarmfrom another Sensor

Any Trip if 2 SensorInputs or Disabled

Adjacent Sensor

OR

OR

RESET

T

T

SETANDLATCH

RESET

SETANDLATCH

RESET

L39VGTT

Gas TurbineTrip

L39VGT

GeneratorTrip

Vibration Trip Contd..

L39VGTT

L39VGTOR

L39VT

HIGHVIBRATIONTRIP

BB 1

BB 2

A A > BB OR

T

LK39DIFF

OTHER SIMILARGROUPS

VibrationDifferentialAlarm

+_

Combustion Monitoring

• Exhaust Temperature Spreads are the Result of Uneven Combustion in all the Combustion Chambers

• Combustion Monitoring is Built in Mark IV/V

• Combustion Monitoring is Enabled after Machine Reaches FSNL

Exhaust Spread Calculations• Actual Spread

))TTXSP1 : Highest - Lowest TC

))TTXSP2 : Highest - 2 nd Lowest TC

))TTXSP3 : Highest - 3 rd Lowest TC

• Allowable Spread ( TTXSPL )

= 0.145 TTXC - 0.08 CTDA + 30 deg F

• During Dynamic Conditions the Allowable Spread is Increased

Trip Conditions•1. TTXSP1 > TTXSPL and

TTXSP2 > 0.8 TTXSPL and

The two Lowest TCs are adjacent

•2. TTXSP1 > 5 TTXSPL and

TTXSP2 > 0.8 TTXSPL and

The 2nd and 3rd Lowest TCs are Adjacent

•3. All Spreads are > TTXSPLTrip : Any of the above Conditions exists

for more than 9 Sec