Neutral Overvoltage (Fundamental); Neutral Overvoltage (3Rd Harmonic) - GE 489 Instruction Manual

4 SETPOINTS
PATH: SETPOINTS S6 VOLTAGE ELEMENTS
NEUTRAL O/V (FUND)
[ENTER] for more
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 con-
junction 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:
D
T ---------------------------------------- - when V V
=
( V V ⁄ ) 1
–
pickup
where T = trip time in seconds
D =
NEUTRAL OVERVOLTAGE TRIP DELAY
V = neutral voltage
V =
NEUTRAL O/V TRIP LEVEL
pickup
The neutral overvoltage curves are shown on the right.
Refer to Appendix B for Application Notes.
GE Multilin
O/V (FUND)
ð
SUPERVISE WITH
ENTER
ð
ESCAPE DIGITAL INPUT: No
NEUTRAL OVERVOLTAGE
ESCAPE
ALARM: Off
MESSAGE
ASSIGN ALARM
ESCAPE
RELAYS (2-5): ---5
MESSAGE
NEUTRAL O/V ALARM
ESCAPE
LEVEL: 3.0 Vsec
MESSAGE
NEUTRAL OVERVOLTAGE
ESCAPE
ALARM DELAY: 1.0 s
MESSAGE
NEUTRAL OVERVOLTAGE
ESCAPE
ALARM EVENTS: Off
MESSAGE
NEUTRAL OVERVOLTAGE
ESCAPE
TRIP: Off
MESSAGE
ASSIGN TRIP
ESCAPE
RELAYS (1-4): 1---
MESSAGE
NEUTRAL O/V TRIP
ESCAPE
LEVEL: 5.0 Vsec
MESSAGE
NEUTRAL OVERVOLTAGE
ESCAPE
TRIP DELAY: 1.0 s
MESSAGE
NEUTRAL O/V CURVE
ESCAPE
RESET RATE: 0.0
MESSAGE
NEUTRAL O/V TRIP
ESCAPE
ELEMENT: Definite Time
MESSAGE
>
(EQ 4.20)
pickup
setpoint
setpoint
489 Generator Management Relay
4.7 S6 VOLTAGE ELEMENTS

4.7.7 NEUTRAL OVERVOLTAGE (FUNDAMENTAL)

Range: Yes, No. Seen only if a digital input assigned to
GROUND SWITCH STATUS
Range: Off, Latched, Unlatched
Range: Any combination of Relays 2 to 5
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 4
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
1000
100
10
1
0.1
1 1.1 1.2 1.3 1.4 1.5
Multiples of Overvoltage Pickup
10
3
1
0.3
0.1
1.6 1.7 1.8 1.9 2
808741A1.CDR
4-39
4