6–52
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION
CHAPTER 6: SETPOINTS
Figure 6-22: Ground/Sensitive Ground instantaneous overcurrent protection logic
diagram
SETPOINT
Ground/Sens. Ground current (Ig)
RUN
SETPOINT
BLOCK 1:
Of
f = 0
GND IOC PICKUP:
Ig > PICKUP
BLOCK 2:
Of
f = 0
BLOCK 3:
Of
f = 0
OR
AND
Operate Output Relay 1 (TRIP)
Event Recorder
Transient Recorder
LED:
TRIP
OR
OR
Cold Load PKP
From Ground CT or
,
From Sens. Ground CT
Block Inputs
AND
SETPOINT
:
Do Not Operate, Operate
OUTPUT
RELA
Y
X
AND
Trip (T
o Breaker Failure)
SETPOINT
GND IOC FUNCTION:
Disabled = 0
Latched
Alarm
Alarm
Trip
GND IOC PKP
DELA
Y:
SETPOINT
t
PKP
0
Event Recorder
Transient Recorder
Autoreclose
(per shot settings)
LED:
ALARM
RESET
Command
AND
S
R
LA
TCH
LED: PICKUP
Ground IOC PKP
Message:
Ground IOC OP
898005A2.cdr
GND
IOC DIRECTION
:
Forward
Disabled
Reverse
AND
AND
GND DIR Reverse
From GROUND DIRECTIONAL
GND DIR Forward
OR
BLK GND DIR OC UND
AND
SETPOINT