Reverse Power - GE Multilin 489 Instruction Manual

5.8.3

Reverse Power

1 REVERSE
POWER
Note
5–62
Courtesy of NationalSwitchgear.com
For example, given Rated MVA = 100 MVA and Rated Power Factor = 0.85, we have
Rated Mvars
=
=
=
PATH: SETPOINTS S7 POWER ELEMENTS
[ ] BLOCK REVERSE POWER
FROM ONLINE: 1 s
REVERSE POWER
MESSAGE
ALARM: Off
ASSIGN ALARM
MESSAGE
RELAYS (2-5): ---5
REVERSE POWER ALARM
MESSAGE
LEVEL: 0.05 x Rated
REVERSE POWER ALARM
MESSAGE
DELAY: 10.0 s
REVERSE POWER ALARM
MESSAGE
EVENTS: Off
REVERSE POWER
MESSAGE
TRIP: Off
ASSIGN TRIP
MESSAGE
RELAYS (1-4): 1---
REVERSE POWER TRIP
MESSAGE
LEVEL: 0.05 x Rated
REVERSE POWER TRIP
MESSAGE
DELAY: 20.0 s
If enabled, once the magnitude of 3-phase total power exceeds the Pickup Level in the
reverse direction (negative MW) for a period of time specified by the Delay, a trip or alarm
will occur. The level is programmed in per unit of generator rated MW calculated from the
rated MVA and rated power factor. If the generator is accelerated from the power system
rather than the prime mover, the reverse power element may be blocked from start for a
specified period of time. A value of zero for the block time indicates that the reverse power
protection is active as soon as both current and voltage are measured regardless of
whether the generator is online or offline. If the VT type is selected as "None" or VT fuse
loss is detected, the reverse power protection is disabled.
The minimum magnitude of power measurement is determined by the phase CT minimum
of 2% rated CT primary. If the level for reverse power is set below that level, a trip or alarm
will only occur once the phase current exceeds the 2% cutoff.
1
–
Rated MVA × sin ( cos ( Rated PF
1
–
100 × sin ( cos 0.85 )
52.67 Mvars
REVERSE POWER
Range: 0 to 5000 s in steps of 1
Range: Off, Latched, Unlatched
Range: Any combination of Relays 2 to
Range: 0.02 to 0.99 × Rated MW in
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
Range: 0.02 to 0.99 × Rated MW in
Range: 0.2 to 120.0 s in steps of 0.1
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
) )
(EQ 5.28)
5
steps of 0.01
4
steps of 0.01