GE 489 - Manual (Page 87)

GE Multilin 489 Generator Management Relay 4-37
4 SETPOINTS 4.7 S6 VOLTAGE ELEMENTS
4
4.7.5 UNDERFREQUENCY
PATH: SETPOINTS ÖØ S6 VOLTAGE ELEMENTS ÖØ UNDERFREQUENCY
It may be undesirable to enable the underfrequency elements until the generator is online. This feature can be blocked until
the generator is online and the block time expires. From that point forward, the underfrequency trip and alarm elements will
be active. A value of zero for the block time indicates that the underfrequency protection is active as soon as voltage
exceeds the cutoff level (programmed as a multiple of the generator rated phase-phase voltage). Frequency is then mea-
sured. Once the frequency of Vab is less than the underfrequency setpoints, for the period of time specified, a trip or alarm
will occur. There are dual level and time setpoints for the trip element.
„ UNDERFREQUENCY
„ [ENTER] for more
BLOCK UNDERFREQUENCY
FROM ONLINE: 1 s
Range: 0 to 5 s in steps of 1
VOLTAGE LEVEL
CUTOFF: 0.50 x Rated
Range: 0.50 to 0.99 × Rated in steps of 0.01
UNDERFREQUENCY
ALARM: Off
Range: Off, Latched, Unlatched
ASSIGN ALARM
RELAYS (2-5): ---5
Range: Any combination of Relays 2 to 5
UNDERFREQUENCY
ALARM LEVEL: 59.50 Hz
Range: 20.00 to 60.00 Hz in steps of 0.01
UNDERFREQUENCY
ALARM DELAY: 5.0 s
Range: 0.1 to 5000.0 s in steps of 0.1
UNDERFREQUENCY
ALARM EVENTS: Off
Range: On, Off
UNDERFREQUENCY
TRIP: Off
Range: Off, Latched, Unlatched
ASSIGN TRIP
RELAYS (1-4): 1---
Range: Any combination of Relays 1 to 4
UNDERFREQUENCY
TRIP LEVEL1: 59.50 Hz
Range: 20.00 to 60.00 Hz in steps of 0.01
UNDERFREQUENCY
TRIP DELAY1: 60.0 s
Range: 0.1 to 5000.0 s in steps of 0.1
UNDERFREQUENCY
TRIP LEVEL2: 58.00 Hz
Range: 20.00 to 60.00 Hz in steps of 0.01
UNDERFREQUENCY
TRIP DELAY2: 30.0 s
Range: 0.1 to 5000.0 s in steps of 0.1
ENTER
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