Volts/Hertz - GE Multilin 489 Instruction Manual

CHAPTER 5: SETPOINTS
5.7.3

Volts/Hertz

1 VOLTS/HERTZ
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
Courtesy of NationalSwitchgear.com
OVERVOLTAGE CURVE
MESSAGE
RESET RATE: 1.4 s
OVERVOLTAGE CURVE
MESSAGE
ELEMENT: Curve
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:
T
-------------------------------------- -
=
( V V ⁄
where: T = trip time in seconds
D =
OVERVOLTAGE TRIP DELAY
V = actual average phase-phase voltage
V =
OVERVOLTAGE TRIP PICKUP
pickup
1000
100
10
1
0.1
1 1.1
PATH: SETPOINTS S6 VOLTAGE ELEM.
[ ] VOLTS/HERTZ
ALARM: Off
ASSIGN ALARM
MESSAGE
RELAYS (2-5): ---5
Range: 0.0 to 999.9 s in steps of 0.1
Range: Curve, Definite Time
D
, when V > V
pickup
) 1
–
pickup
setpoint
setpoint
1.2 1.3 1.4 1.5 1.6 1.7
Multiples of Overvoltage Pickup
FIGURE 5–7: Overvoltage Curves
VOLTS/HERTZ
Range: Off, Latched, Unlatched
Range: Any combination of Relays 2 to
(EQ 5.19)
10
3
1
0.3
0.1
1.8 1.9 2
808741A1.CDR
5
5–45