5 turbine protection

Turbine Protection System

Presentation

on

TURBINE PROTECTION The turbine protection system can be actuated

by any of the following trip systems : -- Hydraulic trip system -- Electrical trip system

Both the trip systems, when initiated, act on the hydraulic control system and cause trip oil pressure to collapse which in turn closes the Emergency stop valves, Interceptor valves and control valves.

HYDRAULIC TRIP SYSTEM• Overspeed trip device 1• Overspeed trip device 2• Vacuum trip device• Thrust Bearing trip device• Hand trip lever 1 (local)• Hand trip lever 2 (local)

TURBINE PROTECTIONS

• LUB OIL PRESSURE LOW• HIGH AXIAL SHIFT• LOW VACUUM• HP EXHAUST TEMP HIGH• HPC TOP-BOTTOM DIFF TEMP HIGH• IPC FRONT TOP-BOTTOM DIFF TEMP HIGH• IPC REAR TOP-BOTTOM DIFF TEMP HIGH• FIRE PROTECTION• MFT• ATRS TRIP• GENERATOR TRIP LEADING TO TURBINE TRIP

TURBINE PROTECTIONS

• LIQUID MAIN LEADS TOP HIGH• COLD GAS COOLERS TEMP A&B HIGH• COLD GAS COOLERS TEMP C&D HIGH• SEAL OIL TEMP AFTER COOLER AIR SIDE HIGH • HOT AIR MAIN EXCITER TEMP HIGH• PRIMARY WATER TEMP AFTER COOLER HIGH • STATOR WINDING FLOW LOW• MAIN BUSHING R FLOW LOW• MAIN BUSHING S FLOW LOW• MAIN BUSHING T FLOW LOW

TURBINE PROTECTIONSTURBINE TRIP (COMPULSARY)– LOW VACUUM– HIGH AXIAL SHIFT– OVERSPEEDING OF TURBINE– MAIN OIL TANK LEVEL LOW– LOW LUBE / CONTROL OIL PRESSURE– MAIN STEAM TEMPERATURE LOW– DRUM LEVEL HIGH TURBINE HAND TRIP FROM

GOVERNING RACK– TURBINE REMOTE PUSH BUTTON TRIP – TURBINE HAND TRIP FROM MOT ROOM / TG FLOOR

(FIRE PROTECTION)– BOILER TRIP LEADING TO TURBINE TRIP– GENERATOR TRIP LEADING TO TURBINE TRIP

TURBINE PROTECTIONSTURBINE ADVISORY TRIP – HIGH SHAFT VIBRATION / ECCENTRICITY– HIGH BEARING VIBRATION – HIGH BEARING METAL TEMPERATURE– HIGH DIFFERENTIAL EXPANSION– HIGH HP/LP EXHAUST TEMPERATURE– TOP – BOTTOM DIFFERENTIAL TEMPERATURE– HIGH MAIN STEAM TEMPERATURE– LOW / HIGH FREQUENCY

GOVERNING RACK

GOVERNING RACK

ELECTRICAL TRIP

CONDITIONS

ELECTRICAL TRIP

CONDITIONS

TRIP RELAY 1

TRIP RELAY 1

TRIP SOLENOID 1

TRIP SOLENOID 2

TURBINE TRIP VALVE

STOP VALVE

HYDRAULIC TRIP

DEVICES

TURBINE PROTECTIONS• Two trip solenoids are provided in the hydraulic circuit, which get trip signals from the electrical system. Actuation of any one solenoid is sufficient to trip the turbine.• The electrical system is configured as a 2-channel system. Each channel is realized in a Processing Unit• Both the processor units are completely independent of each other and input modules, processor module and output modules reside on each.

TURBINE PROTECTIONS

• Each channel having two processors Unit with one processor in hot standby mode .

• Realisation of 2 out of 3 trip logic is carried out in the processor.

• Both the channels are tested periodically even while the turbine is running. Cyclic testing is done automatically at preset intervals

• FIRE PROTECTION: • Fire protection switch either in control room or

in machine hall operated.• Level in main oil tank falls to a very low value

indicating substantial leakage of oil from the system.

• HP EXHAUST TEMP HIGH• During startup/shutdown or load rejections,

steam turbines are operated at very low volumetric flows. Energy transmitted by the turbine shaft is

• converted to thermal energy, which in turn result in an increase in the temp.of both the exhaust steam and turbine components.

AXIAL SHIFT VERY HIGH • A too high axial displacement of the turbine

shaft may cause damage to the turbine blades. The axial shift is measured in both directions (±) using three proximity probes.

HPT/IPT TOP BOTTOM TEMP HIGH • Excessive large temp. differentials within

turbine components cause heat stresses. The temp. differential between upper & lower parts of the turbine casing (HP and IP sections) is a measure of casing distortion.

ISOLATION OF GENERATOR FROM GRID

•Turbine has tripped and reverse power relay has operated. The command signal shall be initiated with a delay of 3 Seconds

•Reverse power relay has operated. The command signal shall be initiated with a time delay of 10 seconds.

OVERSPEED TRIP BOLTS IN BEARING NO. 1 PEDESTAL

BEARING / SHAFT VIBRATION PICK UP MOUNTED ON BEARING NO. 4 PEDESTAL

IP DIFFERENTIAL EXPANSION PICK UP

MOUNTED ON BEARING NO. 3 PEDESTAL

HALL PROBE IN BEARING NO. 1 PEDESTAL

IP DIFFERENTIAL EXPANSION PICK UP

MOUNTED ON BEARING NO. 3 PEDESTAL

LP DIFFERENTIAL EXPANSION PICK UP MOUNTED ON BEARING NO. 4 PEDESTAL

AXIAL SHIFT MEASUREMENT AT IP COLLAR

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