GE Multilin 489 User Manual

5–34 489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
Note
If the unit auxiliary transformer is on the generator side of the breaker, the pickup level
must be set greater than the unit auxiliary load.
5.6.4 Inadvertent Energization
PATH: SETPOINTS ZV S5 CURRENT ELEM. ZV INADVERTENT ENERG.
The logic diagram for the inadvertent energization protection feature is shown below. The
feature may be armed when all of the phase voltages fall below the undervoltage pickup
level and the unit is offline. This would be the case when the VTs are on the generator side
of the disconnect device. If however, the VTs are on the power system side of the
disconnect device, the feature should be armed if all of the phase voltages fall below the
undervoltage pickup level or the unit is offline. When the feature is armed, if any one of the
phase currents measured at the output CTs exceeds the overcurrent level programmed, a
trip will occur.
Note
This feature requires 5 seconds to arm, 250 ms to disarm.
Protection can be provided for poor synchronization by using the “U/V or Offline” arming
signal. During normal synchronization, there should be relatively low current measured. If
however, synchronization is attempted when conditions are not appropriate, a large
current that is measured within 250 ms after the generator is placed online would result in
a trip.
FIGURE 5–1: Inadvertent Energization Logic
1 INADVERTENT [Z]
ENERGIZATION
INADVERTENT ENERGIZE
TRIP: Off
Range: Off, Latched, Unlatched
MESSAGE
ASSIGN TRIP
RELAYS (1-4): 1---
Range: Any combination of Relays 1 to
4
MESSAGE
ARMING SIGNAL:
U/V and Offline
Range: U/V and Offline, U/V or Offline
MESSAGE
INADVERTENT ENERGIZE
O/C PICKUP: 0.05 x CT
Range: 0.05 to 3.00 × CT in steps of
0.01
MESSAGE
INADVERTENT ENERGIZE
PICKUP: 0.50 x Rated
Range: 0.50 to 0.99 × Rated Voltage in
steps of 0.01
AND
AND
AND
OR
OR
OR
OR
V < U/V Level
phase
I > O/C Levelphase
Operate
Breaker Status = Offline
Arming Signal = U/V or Offline
5s
250 ms
808731A1.CDR
Courtesy of NationalSwitchgear.com

GE Multilin 489 Specifications

General

Brand	GE
Model	Multilin 489
Category	Relays
Language	English