6–60
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION
CHAPTER 6: SETPOINTS
Figure 6-25: Neutral Timed Overcurrent Protection: Logic Diagram
SETPOINTS
Neutral current (IN)
RUN
SETPOINTS
BLOCK 1:
Of
f = 0
NTRL
TOC PICKUP:
NTRL
TOC CUR
VE:
NTRL
TO
C
TDM:
IN > PICKUP
BLOCK 2:
Of
f = 0
BLOCK 3:
Of
f = 0
OR
AND
Operate Output Relay 1 (TRIP)
Event Recorder
Transient Recorder
NTRL
TOC PKP
LED:
TRIP
Event Recorder
Transient Recorder
OR
OR
NTRL
TOC OP
Adjust PKP
Cold Load PKP
Computed by the relay
Adjust Neutral T
OC PKP
AND
SETPOINTS:
Do Not Operate, Operate
OUTPUT
RELA
Y X
AND
Trip (T
o Breaker Failure)
NTRL
TOC RESET
:
SETPOINTS
NTRL
TOC DIRECTION:
Forward
Disabled
Reverse
SETPOINT
NTRL
TOC FUNCTION:
Disabled = 0
Latched
Alarm
Alarm
Trip
Autoreclose
(per shot settings)
LED:
ALARM
RESET
Command
AND
S
R
LA
TCH
LED: PICKUP
Message:
898008A2.cdr
AND
AND
NRL
DIR REV
From NEUTRAL
DIRECTIONAL
NRL
DIR FWD
OR
BLK NTRL
DIR OC UND
AND