GE Multilin 489 User Manual

5–92 489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
5.11.4 VT Fuse Failure
PATH: SETPOINTS ZV S10 MONITORING ZV VT FUSE FAILURE
A fuse failure is detected when there are significant levels of negative sequence voltage
without corresponding levels of negative sequence current measured at the output CTs.
Also, if the generator is online and there is not significant positive sequence voltage, it
could indicate that all VT fuses have been pulled or the VTs are racked out. If the alarm is
enabled and a VT fuse failure detected, elements that could nuisance operation are
blocked and an alarm occurs. These blocked elements include voltage restraint for the
phase overcurrent, undervoltage, phase reversal, and all power elements.
FIGURE 5–26: VT Fuse Failure Logic
 VT FUSE [Z]
FAILURE
VT FUSE FAILURE
ALARM: Off
Range: Off, Latched, Unlatched
MESSAGE
ASSIGN ALARM
RELAYS (2-5): ---5
Range: Any combination of Relays 2 to
5
MESSAGE
VT FUSE FAILURE
ALARM EVENTS: Off
Range: On, Off
99ms
99ms
Block
Appropriate
Elements
&
Operate
Alarm
Relay
I/I<20%
21
V/V>25%
21
I>0.075 x CT
1
V>0.05 xFull Scale
1
BreakerStatus = Online
V<0.05 Full Scale
1
×
0
0
AND
OR
AND
Courtesy of NationalSwitchgear.com

GE Multilin 489 Specifications

General

Brand	GE
Model	Multilin 489
Category	Relays
Language	English