CHAPTER 6: SETPOINTS
S3 PROTECTION
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
6–75
Figure 6-32: Phase undervoltage logic diagram
Phase V
oltage Inputs
(associated setpoints)
SETPOINTS
Va
b
SETPOINT
PH UV FUNCTION:
Disabled = 0
Latched
Alarm
PH UV PICKUP:
PH UV CUR
VE:
PH UV DELA
Y:
AND
Vbc
Vca
Operate Output Relay 1 (TRIP)
Event Recorder
LED:
TRIP
Alarm
OR
OR
AND
SETPOINTS
Do Not Operate, Operate
OUTPUT
RELA
Y X
Trip
AND
Trip (T
o Breaker Failure)
SETPOINTS
BLOCK 1:
Of
f = 0
BLOCK 2:
Of
f = 0
BLOCK 3:
Of
f = 0
OR
RUN
RUN
RUN
PICKUP
Va
n
Vbn
Vcn
None
PICKUP
PICKUP
Van or V
ab > Minimum
Vbn or Vbc > Minimum
Vcn or Vca > Minimum
PH UV MIN VOL
TAGE:
SETPOINT
AND
AND
AND
Delta
Wye
All
Three
Any One
Any
Tw
o
Operate for
programmed
combination
Any
Tw
o
Any One
All
Three
Pickup for
Programmed
Combination
SETPOINT
PH UV PHASES:
OR
OR
LED: PICKUP
Phase Undervoltage
Message
LED:
ALARM
RESET
Command
AND
S
R
LA
TCH
898014A2.cdr