GE 350-A9

CHAPTER 6: SETPOINTS S3 PROTECTION
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL 6–65
Figure 6-27: Neutral Instantaneous Overcurrent Protection: Logic Diagram
SETPOINT
Neutral current (IN)
RUN
SETPOINT
BLOCK 1: Off = 0
NTRL IOC PICKUP:
IN > PICKUP
BLOCK 2: Off = 0 BLOCK 3: Off = 0
OR
AND
Operate Output Relay 1 (TRIP)
Event Recorder
Transient Recorder
LED: TRIP
OR
OR
Cold Load PKP
Autoreclose
(per shot settings)
Computed by the relay
Block Inputs
AND
SETPOINT:
Do Not Operate, Operate
OUTPUT RELAY X
AND
SETPOINT
NTRL IOC FUNCTION:
Disabled = 0
Latched Alarm Alarm
Trip
NTRL IOC PKP DLY:
SETPOINT
t
PKP
0
Event Recorder
Transient Recorder
LED: ALARM
RESET
Command
AND
S R
LATCH
LED: PICKUP
Neutral IOC PKP
Message:
Neutral IOC OP
898007A2.cdr
SETPOINT
NTRL IOC DIRECTION:
Forward
Disabled
Reverse
AND AND
NRL DIR Reverse
From NEUTRAL DIRECTIONAL
NRL DIR Forward
OR
BLK NTRL DIR OC UND
AND