
6–44
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION
CHAPTER 6: SETPOINTS
Figure 6-18: Phase instantaneous overcurrent protection logic diagram
SETPOINT
Phase
A current (IA)
RUN
SETPOINT
PH IOC FUNCTION:
Disabled = 0
Latched
Alarm
PH IOC PICKUP:
PH IOC PKP
DELA
Y:
Phase B current (IB)
Phase C current (IC)
RUN
RUN
Operate Output Relay 1 (TRIP)
Event Recorder
Transient Recorder
LED: PICKUP
LED:
TRIP
Event Recorder
Transient Recorder
Alarm
OR
OR
Cold Load PKP
Autoreclose
(per shot settings)
Phase Currents
Block Inputs
AND
SETPOINT
:
Do Not Operate, Operate
OUTPUT
RELA
Y X
Trip
AND
SETPOINT
BLOCK 1:
Of
f = 0
BLOCK 2:
Of
f = 0
BLOCK 3:
Of
f = 0
OR
Message
Phase IOC OP
IB
>
PICKUP
IA
>
PICKUP
IC
>
PICKUP
SETPOINT
Phase IOC
A OP
Phase IOC B OP
Phase IOC C OP
Phase IOC
A PKP
Phase IOC B PKP
Phase IOC C PKP
Phase IOC PKP
Message
t
PKP
0
t
PKP
0
t
PKP
0
OR
OR
Trip (T
o Breaker Failure)
LED:
ALARM
RESET
Command
AND
S
R
LA
TCH
898009A2.cdr
AND
Block
TOC Dir Phase
A
From T
OC PHASE DIRECTIONAL
Block
TOC Dir Phase B
Block
TOC Dir Phase C
AND
AND
AND