CHAPTER 6: SETPOINTS
S3 PROTECTION
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
6–83
Figure 23: Neutral Instantaneous Overcurrent Protection: Logic Diagram
SETPOINT
Neutral
current
(IN)
RUN
SETPOINT
BLOCK
1:
O
ff=0
NTRL
IOC
PICKUP:
IN
>
PICKUP
BLOCK
2:
O
ff=0
BLOCK
3:
O
ff=0
OR
AND
Operate
Output
Relay
1
(TRIP)
Event
Recorder
T
ransient
Recorder
LED:
TRIP
OR
OR
Cold
Load
PKP
Autoreclose
(per
shot
settings)
Computed
by
the
relay
Block
Inputs
AND
SETPOINT
:
Operate
output
relay
upon
selection
OUTPUT
RELA
Y
4
OUTPUT
RELA
Y
5
OUTPUT
RELA
Y
6
OUTPUT
RELA
Y
3
AND
SETPOINT
NTRL
IOC
DIRECTN:
Forward
Disabled
Reverse
SETPOINT
NTRL
IOC
FUNCTION:
Disabled
=
0
Latched
Alarm
Alarm
T
rip
AND
AND
Current
in
Reverse
From
NEUTRAL
DIRECTIONAL
Current
OK
NTRL
IOC
PKP
DL
Y
:
SETPOINT
t PKP
0
Event
Recorder
T
ransient
Recorder
LED:
ALARM
RESET
Command
AND
S
R
LA
TCH
LED:
PICKUP
Neutral
IOC
PKP
Message:
Neutral
IOC
OP
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