GE 350-A9

6–88 350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION CHAPTER 6: SETPOINTS
Figure 6-39: Underfrequency logic diagram
Phase Voltage Inputs
(associated setpoints)
SETPOINTS
Vab
SETPOINT
UNDERFREQ FUNCTN: Disabled = 0
Latched Alarm
UNDERFREQ PKP:
Vbc Vca
Operate Output Relay 1 (TRIP)
Event Recorder
Transient Recorder
LED: TRIP
Alarm
OR
OR
AND
SETPOINTS
Do Not Operate, Operate
OUTPUT RELAY X
Trip
AND
Trip (To Breaker Failure)
SETPOINTS
BLOCK 1: Off = 0 BLOCK 2: Off = 0 BLOCK 3: Off = 0
OR
RUN
Van Vbn
Vcn
None
AND
DeltaWye
LED: PICKUP
Event Recorder
Transient Recorder
Underfrequency1(2)
Message
f < PICKUP
Frequency
Measurement
f ( Va) - frequency
Va > Minimum
MIN VOLTAGE:
SETPOINT
f = 0
UNDERFREQ DELAY:
SETPOINT
t
PKP
LED: ALARM
RESET
Command
AND
S R
LATCH
898004A1.cdr