6–72
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION
CHAPTER 6: SETPOINTS
Figure 19: Ground/Sensitive Ground instantaneous overcurrent protection logic
diagram
SETPOINT
Ground/Sens.
Ground
current
(Ig)
RUN
SETPOINT
BLOCK
1:
O
ff=0
GND
IOC
PICKUP:
Ig
>
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
From
Ground
CT
or
,
From
Sens.
Ground
CT
Block
Inputs
AND
SETPOINT
:
Operate
output
relays
upon
selection
OUTPUT
RELA
Y
4
OUTPUT
RELA
Y
5
OUTPUT
RELA
Y
6
OUTPUT
RELA
Y
3
AND
T
rip
(T
o
Breaker
Failure)
SETPOINT
GND
IOC
FUNCTION:
Disabled
=
0
Latched
Alarm
Alarm
T
rip
GND
IOC
PKP
DELA
Y
:
SETPOINT
t
PKP
0
Event
Recorder
T
ransient
Recorder
Autoreclose
(per
shot
settings)
LED:
ALARM
RESET
Command
AND
S
R
LA
TCH
LED:
PICKUP
Ground
IOC
PKP
Message:
Ground
IOC
OP
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