Neutral Overvoltage - GE Multilin 489 Instruction Manual

CHAPTER 5: SETPOINTS
5.7.7

Neutral Overvoltage

1 NEUTRAL O/V
(FUNDAMENTAL)
Note
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
Courtesy of NationalSwitchgear.com
PATH: SETPOINTS S6 VOLTAGE ELEM.
[ ] SUPERVISE WITH
DIGITAL INPUT: No
NEUTRAL OVERVOLTAGE
MESSAGE
ALARM: Off
ASSIGN ALARM
MESSAGE
RELAYS (2-5): ---5
NEUTRAL O/V ALARM
MESSAGE
LEVEL: 3.0 Vsec
NEUTRAL OVERVOLTAGE
MESSAGE
ALARM DELAY: 1.0 s
NEUTRAL OVERVOLTAGE
MESSAGE
ALARM EVENTS: Off
NEUTRAL OVERVOLTAGE
MESSAGE
TRIP: Off
ASSIGN TRIP
MESSAGE
RELAYS (1-4): 1---
NEUTRAL O/V TRIP
MESSAGE
LEVEL: 5.0 Vsec
NEUTRAL OVERVOLTAGE
MESSAGE
TRIP DELAY: 1.0 s
NEUTRAL O/V CURVE
MESSAGE
RESET RATE: 0.0
NEUTRAL O/V TRIP
MESSAGE
ELEM.: Time
The
SUPERVISE WITH DIGITAL INPUT
Ground Switch Status.
The neutral overvoltage function responds to fundamental frequency voltage at the
generator neutral. It provides ground fault protection for approximately 95% of the stator
windings. 100% protection is provided when this element is used in conjunction with the
Neutral Undervoltage (3rd harmonic) function. The alarm element is definite time and the
trip element can be either definite time or an inverse time curve. When the neutral voltage
rises above the pickup level the element will begin to time out. If the time expires an alarm
or trip will occur. The reset rate is a linear reset time from the threshold of trip. The alarm
and trip levels are programmable in terms of Neutral VT secondary voltage.
The formula for the curve is:
T
-------------------------------------- -
=
( V V ⁄
NEUTRAL O/V (FUNDAMENTAL)
Range: Yes, No
Range: Off, Latched, Unlatched
Range: Any combination of Relays 2 to
Range: 2.0 to 100.0 Vsec in steps of 0.1
Range: 0.1 to 120.0 s in steps of 0.1
Range: On, Off
Range: Off, Latched, Unlatched
Range: Any combination of Relays 1 to
Range: 2.0 to 100.0 Vsec in steps of 0.1
Range: 0.1 to 120.0 s in steps of 0.1
Range: 0.0 to 999.9 in steps of 0.1
Range: Curve, Definite Time
setpoint is seen only if a digital input assigned to
D
when V > V
pickup
) 1
–
pickup
5
4
(EQ 5.23)
5–51