Neutral Overcurrent; Description; Neutral Time Overcurrent - GE 750 Instruction Manual

12.3 NEUTRAL OVERCURRENT

12.3 NEUTRAL OVERCURRENT
Four neutral overcurrent protection elements are provided. Two time overcurrent elements and two instanta-
neous overcurrent elements. They all monitor the calculated neutral current (3 I
set and harmonic components removed. Neutral overcurrent elements can be controlled by the neutral
directional element allowing operation for faults in the permitted direction only. Also, the elements can be
blocked individually or as a group by logic inputs.
12
Neutral time overcurrent elements 1 and 2 are programmed in this subgroup. They are two identical protection
elements each equivalent to a single ANSI device 51N neutral time overcurrent relay.
NEUTRAL TIME OC 1
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NEUTRAL TIME OC 1
FUNCTION: Disabled
NEUTRAL TIME OC 1
RELAYS (3-7): -----
NEUTRAL TIME OC 1
PICKUP: 1.00 x CT
NEUTRAL TIME OC 1
CURVE: Ext Inverse
NEUTRAL TIME OC 1
MULTIPLIER:
NEUTRAL TIME OC 1
RESET: Instantaneous
NEUTRAL TIME OC 1
DIRECTION: Disabled
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Courtesy of NationalSwitchgear.com
The Neutral Time Overcurrent 1 setpoints path is:
\ SETPOINTS \ S5 PROTECTION \ NEUTRAL CURRENT \ NEUTRAL TIME OC 1
Range: Disabled, Trip, Trip & AR, Alarm, Latched Alarm, Control
Select the required function.
Range: Any Combination of the 3-7 AUXILIARY Relays
Select the output relays required.
Range: 0.05 to 20.00 in steps of 0.01 x CT
Select the current level required.
Range: Ext Inverse, Very Inverse, Norm Inverse, ..., Flex Curve B
See description in Section 12.1: TIME OVERCURRENT CURVE CHARAC-
TERISTICS on page 12–1.
Range: 0.00 to 100.00 in steps of 0.01
1.00
See description in Section 12.1: TIME OVERCURRENT CURVE CHARAC-
TERISTICS on page 12–1.
Range: Instantaneous, Linear
See description in Section 12.1: TIME OVERCURRENT CURVE CHARAC-
TERISTICS on page 12–1.
Range: Disabled, Forward, Reverse
Select the direction(s) of current flow for which operation is permitted.
750/760 Feeder Management Relay
12 S5 PROTECTION

12.3.1 DESCRIPTION

= I + I + I
) which has DC off-
o a b c

12.3.2 NEUTRAL TIME OVERCURRENT

GE Power Management