Neutral Time Delayed Overcurrent Unit (51N); Neutral Instantaneous Overcurrent Unit (50N); 51N Unit Setpoints - GE Multilin F650 Instruction Manual

5 SETPOINTS
The F650 Neutral Current menu incorporates the following overcurrent elements:
• Neutral time overcurrent (51N)
• Neutral instantaneous overcurrent (50N)
• Neutral directional unit (67N)

5.4.4.1 NEUTRAL TIME DELAYED OVERCURRENT UNIT (51N)

Unit 51N is a neutral time delayed overcurrent protection element. This unit uses as input quantity the neutral current,
calculated from the phase currents. Trip can be timed by a curve selectable by setpoint. Reset can be instantaneous or
linear.
Table 5–44: 51N UNIT SETPOINTS
SETPOINT > PROTECTION ELEMENTS > NEUTRAL CURRENT > NEUTRAL TOC
NEUTRAL TOC 1> NEUTRAL TOC 2 > NEUTRAL TOC 3
SETPOINT DESCRIPTION
Function permission
Pickup level
Curve shape
Time Dial
Reset type
Snapshot Event generation
The snapshot event setpoint enables or disables the snapshot event generation for this unit.

5.4.4.2 NEUTRAL INSTANTANEOUS OVERCURRENT UNIT (50N)

This function can be used as an instantaneous unit or as a definite time unit. The unit responds to the neutral current
fundamental harmonic magnitude, calculated from the phase currents.
Table 5–45: 50N UNIT SETPOINTS
SETPOINT > PROTECTION ELEMENTS > NEUTRAL CURRENT > NEUTRAL IOC
NEUTRAL IOC 1> NEUTRAL IOC 2 > NEUTRAL IOC 3
SETPOINT DESCRIPTION
Function permission
Pickup level
Trip time
Reset time
Snapshot event generation
The snapshot event setpoint enables or disables the snapshot event generation for this unit.
GE Multilin
NAME DEFAULT VALUE
Function DISABLED
Pickup Level 1.00
Curve IEEE Ext Inv
TD Multiplier 1.00
Reset INSTANTANEOUS
Snapshot Events ENABLED
NAME DEFAULT
VALUE
Function DISABLED
Pickup Level 30.00
Trip Delay 0.00
Reset Delay 0.00
Snapshot Events ENABLED
F650 Digital Bay Controller
5.4 PROTECTION ELEMENTS
5.4.4 NEUTRAL CURRENT
STEP RANGE
N/A [DISABLED – ENABLED]
0.01 A [0.05 : 160.00]
N/A [See list of curves]
0.01 s [0.00 : 900.00]
N/A [INSTANTANEOUS – LINEAR]
N/A [DISABLED – ENABLED]
STEP RANGE
N/A [DISABLED – ENABLED]
0.01 A [0.05 : 160.00]
0.01 s [0.00 : 900.00]
0.01 s [0.00 : 900.00]
N/A [DISABLED – ENABLED]
5
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