CHAPTER 4: SETPOINTS PROTECTION
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL 4–189
Figure 4-75: Phase Undervoltage Protection logic diagram
894046A2.cdr
SETPOINTS
SETPOINT
FUNCTION:
Disabled
Trip
PICKUP:
AND
Operate Output Relay 1 (TRIP)
LED: PICKUP
LED: TRIP
OR
Alarm
OR
OR
AND
Latched Alarm
AND
RUN
SETPOINTS
BLOCK :
Off = 0
LED: ALARM /
LATCHED ALARM
RESET
Command
AND
S
R
LATCH
Configurable
FlexLogic Operands
Phase UV1 OP:
Phase UV1 PKP:
Phase UV1 PKP C:
Phase UV1 PKP B:
Phase UV1 PKP A:
SETPOINTS
MODE: Phase to Ground,
Phase to Phase (for wye
connection)
Phase to Phase (Delta VTs)
RUN
RUN
PICK-UP DELAY:
UNDERVOLTAGE
CURVES:
VA(VAB) < PICKUP
VB(VBC) < PICKUP
VC(VCA) < PICKUP
OR
SETPOINTS
OPERATE:
ANY ONE
ANY TWO
ALL THREE
PHASES FOR
OPERATION:
PICK-UP:
ANY ONE
ANY TWO
ALL THREE
SETPOINTS
MINIMUM VOLTAGE:
VA(VAB) > MINIMUM
AND AND
VB(VBC) > MINIMUM
VC(VCA) > MINIMUM
AND
Phase UV1 OP C:
Phase UV1 OP B:
Phase UV1 OP A:
MODE:
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Phase A voltage (VA)
Phase B voltage (VB)
Phase C voltage (VC)
Phase-to-Ground Voltages –
Wye connection
Ph-Ph AB voltage (VAB)
Ph-Ph BC voltage (VBC)
Ph-Ph CA voltage (VCA)
Phase-to-Phase Voltages –
Delta connection
Ph-Ph AB voltage (VAB)
Ph-Ph BC voltage (VBC)
Ph-Ph CA voltage (VCA)
Calculated Phase-to-Phase
Voltages – Wye connection
SETPOINTS
Do Not Operate, Operate
OUTPUT RELAYS 3 to 7
SETPOINTS
SIGNAL INPUT:
NAME( Ph VT Bnk1-J2
889 only