GE Multilin 345 - Page 160

6–44 345 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION CHAPTER 6: SETPOINTS
BLOCK 1/2/3
For details see Common setpoints
.
Figure 6-20: Percent Differential Protection logic diagram
SETPOINT
Phase A current (IA2d)
SETPOINT
PERCENT DIFF FUNCTION: Disabled = 0
Latched Alarm
MINIMUM PICKUP:
AND
Phase B current (IB2d) Phase C current (IC2d)
Operate Output Relay 1 (W1 BKR TRIP)
LED: ALARM
LED: TRIP
Event Recorder
Transient Recorder
Alarm
OR
OR
Differential 2nd Harmonic
AND
SETPOINT
Do Not Operate, Operate
OUTPUT RELAY X
Trip
AND
SETPOINT
BLOCK 1: Off = 0 BLOCK 2: Off = 0 BLOCK 3: Off = 0
OR
Message
OR
Trip (To Breaker Failure)
Phase A Diff Current (IAd)
Differential Currents
Restraint Currents
SETPOINT
INRUSH INHIBIT FUNCTION Disabled = 0 2nd harmonic
SLOPE 1 BREAKPOINT 1 BREAKPOINT 2 SLOPE 2 INRUSH INHIBIT LEVEL RUN RUN RUN
INRUSH INHIBIT LEVEL INRUSH INHIBIT MODE
IA2d = LEVEL
SETPOINT
RUN RUN
SETPOINT
OVEREXCITATION INHIBIT FUNCTION Disabled = 0 5th harmonic =1
Phase A current (IA5d) Phase B current (IB5d) Phase C current (IC5d)
Differential 5th Harmonic
OVEREXC INHIBIT LEVEL
SETPOINT
RUN RUN
RUN
AND
AND
AND
PCNT DIFF PH C PKP
Message
Event Recorder
Transient Recorder
LED: PICKUP
OR
RESET
Command
AND
S R
LATCH
PCNT DIFF PH A OP
PCNT DIFF PH B PKP PCNT DIFF PH A PKP
PCNT DIFF PKP
RUN
Operate Output Relay 2 (W2 BKR TRIP)
Event Recorder
2ND HMNC DIFF PH A
Event Recorder
Phase B Diff Current (IBd)
Phase C Diff Current (ICd)
Phase A Rest Current (IAr) Phase B Rest Current (IBr) Phase C Rest Current (ICr)
IB2d = LEVEL IC2d = LEVEL IA5d = LEVEL IB5d = LEVEL IC5d = LEVEL
2ND HMNC DIFF PH B 2ND HMNC DIFF PH C
5TH HMNC DIFF PH A 5TH HMNC DIFF PH B 5TH HMNC DIFF PH C
PCNT DIFF PH B OP PCNT DIFF PH C OP PCNT DIFF OP
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