Overvoltage - GE 489 Instruction Manual

4.7 S6 VOLTAGE ELEMENTS
PATH: SETPOINTS S6 VOLTAGE ELEMENTS

OVERVOLTAGE

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4
The overvoltage elements may be used for protection of the generator and/or its auxiliary equipment during prolonged
overvoltage conditions. They are always active (when the generator is offline or online). The alarm element is definite time
and the trip element can be either definite time or an inverse time curve. When the average of the measured phase-phase
voltages rises above the pickup level x the generator rated phase-phase voltage, the element will begin to time out. If the
time expires, a trip or alarm will occur. The reset rate is a linear reset time from the threshold of trip. The pickup levels are
insensitive to frequency over the range of 5 to 90 Hz.
The formula for the curve is:
D
T ---------------------------------------- - ,
=
( ⁄ ) 1
V V
–
pickup
where: T = trip time in seconds
D =
OVERVOLTAGE TRIP DELAY
V = actual average phase-phase voltage
V =
OVERVOLTAGE TRIP PICKUP
pickup
4-34
OVERVOLTAGE
ð
OVERVOLTAGE
ENTER
ð
ESCAPE ALARM: Off
ASSIGN ALARM
ESCAPE
RELAYS (2-5): ---5
MESSAGE
OVERVOLTAGE ALARM
ESCAPE
PICKUP: 1.15 x Rated
MESSAGE
OVERVOLTAGE ALARM
ESCAPE
DELAY: 3.0 s
MESSAGE
OVERVOLTAGE ALARM
ESCAPE
EVENTS: Off
MESSAGE
OVERVOLTAGE
ESCAPE
TRIP: Off
MESSAGE
ASSIGN TRIP
ESCAPE
RELAYS (1-4): 1---
MESSAGE
OVERVOLTAGE TRIP
ESCAPE
PICKUP: 1.20 x Rated
MESSAGE
OVERVOLTAGE TRIP
ESCAPE
DELAY: 1.0 s
MESSAGE
OVERVOLTAGE CURVE
ESCAPE
RESET RATE: 1.4 s
MESSAGE
OVERVOLTAGE CURVE
ESCAPE
ELEMENT: Curve
MESSAGE
>
when V V
(EQ 4.19)
pickup
setpoint
setpoint
489 Generator Management Relay
Range: Off, Latched, Unlatched
Range: Any combination of Relays 2 to 5
Range: 1.01 to 1.50 × Rated in steps of 0.01
Range: 0.2 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: 1.01 to 1.50 × Rated in steps of 0.01
Range: 0.1 to 10.0 s in steps of 0.1
Range: 0.0 to 999.9 s 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
4 SETPOINTS
4.7.2 OVERVOLTAGE
10
3
1
0.3
0.1
1.6 1.7 1.8 1.9 2
808741A1.CDR
GE Multilin