GE 489 - Manual (Page 84)

4-34 489 Generator Management Relay GE Multilin
4.7 S6 VOLTAGE ELEMENTS 4 SETPOINTS
4
4.7.2 OVERVOLTAGE
PATH: SETPOINTS ÖØ S6 VOLTAGE ELEMENTS ÖØ OVERVOLTAGE
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.
„ OVERVOLTAGE
„ [ENTER] for more
OVERVOLTAGE
ALARM: Off
Range: Off, Latched, Unlatched
ASSIGN ALARM
RELAYS (2-5): ---5
Range: Any combination of Relays 2 to 5
OVERVOLTAGE ALARM
PICKUP: 1.15 x Rated
Range: 1.01 to 1.50 × Rated in steps of 0.01
OVERVOLTAGE ALARM
DELAY: 3.0 s
Range: 0.2 to 120.0 s in steps of 0.1
OVERVOLTAGE ALARM
EVENTS: Off
Range: On, Off
OVERVOLTAGE
TRIP: Off
Range: Off, Latched, Unlatched
ASSIGN TRIP
RELAYS (1-4): 1---
Range: Any combination of Relays 1 to 4
OVERVOLTAGE TRIP
PICKUP: 1.20 x Rated
Range: 1.01 to 1.50 × Rated in steps of 0.01
OVERVOLTAGE TRIP
DELAY: 1.0 s
Range: 0.1 to 10.0 s in steps of 0.1
OVERVOLTAGE CURVE
RESET RATE: 1.4 s
Range: 0.0 to 999.9 s in steps of 0.1
OVERVOLTAGE CURVE
ELEMENT: Curve
Range: Curve, Definite Time
The formula for the curve is:
(EQ 4.19)
where: T = trip time in seconds
D = OVERVOLTAGE TRIP DELAY setpoint
V = actual average phase-phase voltage
V
pickup
= OVERVOLTAGE TRIP PICKUP setpoint
ENTER
ESCAPE
р
р
MESSAGE
ESCAPE
MESSAGE
ESCAPE
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ESCAPE
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ESCAPE
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ESCAPE
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ESCAPE
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ESCAPE
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ESCAPE
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ESCAPE
T
D
V V
pickup
⁄ ( ) 1
–
----------------------------------------- = , when V V
pickup
>
808741A1.CDR
0.1
1
10
100
1000
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2
Multiples of Overvoltage Pickup
10
3
1
0.3
0.1
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