Low Forward Power - GE Multilin 489 Instruction Manual
Generator management relay
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Also See for Multilin 489:
- Instruction manual (306 pages) ,
- Communications manual (78 pages) ,
- Instruction manual (38 pages)
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CHAPTER 5: SETPOINTS
5.8.4
Low Forward Power
1 LOW FORWARD
POWER
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
Courtesy of NationalSwitchgear.com
Users are cautioned that a reverse power element may not provide reliable indication
when set to a very low setting, particularly under conditions of large reactive loading on
the generator. Under such conditions, low forward power is a more reliable element.
PATH: SETPOINTS
S7 POWER ELEMENTS
[ ]
BLOCK LOW FWD POWER
FROM ONLINE: 0 s
LOW FORWARD POWER
MESSAGE
ALARM: Off
ASSIGN ALARM
MESSAGE
RELAYS (2-5): ---5
LOW FWD POWER ALARM
MESSAGE
LEVEL: 0.05 x Rated
LOW FWD POWER ALARM
MESSAGE
DELAY: 10.0 s
LOW FWD POWER ALARM
MESSAGE
EVENTS: Off
LOW FORWARD POWER
MESSAGE
TRIP: Off
ASSIGN TRIP
MESSAGE
RELAYS (1-4): 1---
LOW FWD POWER TRIP
MESSAGE
LEVEL: 0.05 x Rated
LOW FWD POWER TRIP
MESSAGE
DELAY: 20.0 s
If enabled, once the magnitude of 3-phase total power in the forward direction (+MW) falls
below the Pickup Level for a period of time specified by the Delay, an alarm will occur. The
level is programmed in per unit of generator rated MW calculated from the rated MVA and
rated power factor. The low forward power element is active only when the generator is
online and will be blocked until the generator is brought online, for a period of time defined
by the setpoint Block Low Fwd Power From Online. The pickup level should be set lower
than expected generator loading during normal operations. If the VT type is selected as
"None" or VT fuse loss is detected, the low forward power protection is disabled.
LOW FORWARD POWER
Range: 0 to 15000 s in steps of 1
Range: Off, Latched, Unlatched
Range: Any combination of Relays 2 to
5
Range: 0.02 to 0.99 × Rated MW 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: 0.02 to 0.99 × Rated MW in
steps of 0.01
Range: 0.2 to 120.0 s in steps of 0.1
5–63
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