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Types of trip-outClass-A
Trip Turbine GCB,FCB
-load rejection-over speed-field suppression-unit shut down
-fast possible,elect.and mech.prot.-Over speed risk-stresses owing toload rejection
Class-B
Trip Turbine Trip GCB,FCB
on reverse power
-Normal unloadingby closing steam-Reverse power-field suppression-unit shut down
slowelectandmechprot.with out over speed risk andload rejection.On time delay trips GCB, FC(15 sec)
Class-C
Trip GCB,FCB
-load rejection-over speed-field suppression-unit remains at rated speed
Fast elect.prot.,it ispossible to synch. again with in short time
Class-D
Trip Unit CB
-load rejection-over speed-Island operation
Protection againstexternal grid faultsAux.service supplyis possible
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TYPICAL TRIPPING LOGIC
GENTRIPRELAY
86G1
GENTRIPRELAY
86G2
CLASS ‘A’ TRIP (SEV.ELE FAULTS)
GEN DIFFERENTIAL (86G) GEN T/F DIFFERENTIAL (86T) GEN STATOR E/F (64G1)(0-95%) GEN REV POWER(32G1)+TURBINE ESV CLOSED GEN REV POWER(32G1)+TURBINE ESV OPENED GEN OVER VOLTAGE (59 G1)(MODERATE)UAT BACK-UP OVER CURRENT (50-51 UAT) UAT PRESSURE RELIEF
UAT BUCH HOLZ (2ND STAGE) GEN MIN IMPEDANCE (21G) (1ST STAGE)
GEN T/F BKR STUCK (50LBB) UAT MULSIFIER TRIP
GEN AND T/F OVER ALL DIFFERENTIAL (87GT)
UAT DIFFERENTIAL (87UAT)GEN STATOR E/F (64G1)
LOW FORWARD POWER RALAY (32G2)
GEN OVER VOLTAGE (59 G1)(EXTREME)
GEN ROTOR E/F (64R1)(2ND STAGE)
GEN T/F OVER FLUXING (99 GT)
GEN T/F REF(64 GT)
GEN T/F O/C,BACK-UP E/F (51 GT+51NGT)
GEN T/F BUCHHOLZ (2ND STAGE)
GEN T/F OLTC BUCHHOLZ (2nd STAGE)
GEN T/F PR.RELIEF TRIP
T
TV/B
V/B
V/B 52GT 86G3
TOTRIP GT BKR
TO TRIP GEN FIELD BKR
TO TRIP EX.FIELD BKR
TO TRIP TURBINE
FAST AUTO C/ O UNIT SUPPLY
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TYPICAL TRIPPING LOGIC
GENTRIPRELAY
86G1
GENTRIPRELAY
86G2
CLASS ‘B’ TRIP
-VE SEQUENCE PROTECTION (46G)(I2 T TRIP)
LOSS OF EXCITATION (40G)
86 G1 OPERATED
86 G2 OPERATED
GEN T/F OIL,WDG TEMP HI-HI
GEN OUT OF STEP RELAY (98G)
GEN UNDER FREQUENCY(81 G)
GEN MIN IMPEDANCE 2ND STEP
V/B
V/B
52GT
TO LPF INTER LOCK
TO TRIP TURBINE
FOR OVERLAPPING AUTO C/ O OF UNIT SUPPLY
UAT OIL,WDG TEMP HI-HI
-VE SEQUENCE PROTECTION (46G)(I2 T TRIP)
V/B
TO TRIP GEN T/F BKRISLAND MODE
CLASS ‘C’ TRIP (OUT SIDE FAULTS)
1EARTH
NGT & NGR
GCB
70 MVA 132/11KV MAIN POWER T/F
UAT11 / 6.6 KV
10 MVA
LINECT
NEUTRALCT
A
132 KV
11 KV
6.6 KV
6.6 kV SWGR
SLD OFGEN AND GEN T/F.
CT
Slide 73
1
98G, 40G1, 51G, 21G1, 50GDM, 50GLBB, 40G2, 46G
CT1
CT 2 CT3
CT4
CT5
CT6
CT 7
CT38
CT9
CT10
87G1
87G2
87G2
87G1
37G1, 37G2
AVR CH 2, LOAD TRANSDUCER
AVR CH 1
METERING
87TLVT 1,2,3
VT 4
27G1, 27G2, 59G1, 81G1, 96G, 99G, 64G1
27GT, 99GT, 64GT
96G, 64GIT ON NEUTRAL
GCB
GEN
NGR GEN PROTECTIONSSINGLE LINE DIAGRAM
