GE 489

4-66 489 Generator Management Relay
GE Power Management
4.11 S10 MONITORING 4 SETPOINT PROGRAMMING
4
If 52 Open/Closed is selected, the trip coil supervision circuitry monitors the trip coil circuit for continuity at all times regard-
less of breaker state. This requires an alternate path around the 52a contacts in series with the trip coil when the breaker is
open. See the figure below for modifications to the wiring and proper resistor selection. If that continuity is broken, a Starter
Failure alarm will indicate Trip Coil Supervision.
Figure 4–19: TRIP COIL SUPERVISION
4.11.4 VT FUSE FAILURE
A fuse failure is detected when there are significant levels of negative sequence voltage without correspondingly significant
levels of negative sequence current measured at the output CTs. Also, if the generator is online and there is not a signifi-
cant amount of positive sequence voltage, it could indicate that all the VT fuses have been pulled or the VTs have been
racked out. If the alarm is enabled and a VT fuse failure has been detected elements that could nuisance operate will be
blocked and an alarm will occur. Those elements that will be blocked include voltage restraint for the phase overcurrent,
undervoltage, phase reversal, and all power elements.
Figure 4–20: VT FUSE FAILURE

VT FUSE FAILURE

[ENTER] for more
VT FUSE FAILURE
ALARM: Off
Range: Off, Latched, Unlatched
ASSIGN ALARM
RELAYS (2-5): ---5
Range: Any combination of Relays 2 to 5
VT FUSE FAILURE
ALARM EVENTS: Off
Range: On, Off
VALUE OF RESISTOR 'R'
SUPPLY
OHMS
WATTS
48 VDC
125 VDC
250 VDC
10 K
25 K
50 K
2
5
5
TRIP
COIL
TRIP COIL
SUPERVISION
R1 TRIP
CONTACT
F11
E2
F1
E11
52a
TRIP COIL CLOSED SUPERVISION
"52 Closed"
TRIP COIL
SUPERVISION
R1 TRIP
CONTACT
TRIP
COIL
F11
E2
F1
E11
52a
TRIP COIL OPEN/CLOSED SUPERVISION
"52 Open/Closed"
52a
TRIP
COIL
TRIP COIL
SUPERVISION
R1 TRIP
CONTACT
F11
E2
F1
E11
52a
TRIP COIL
OPEN/CLOSED
SUPERVISION
"52 Open/Closed"
WITH MULTIPLE
BREAKER AUX
CONTACTS
ENTER
ESCAPE
ð
ð
MESSAGE
ESCAPE
MESSAGE
ESCAPE
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 x Full Scale
1
Breaker Status = Online
V < 0.05 Full Scale
1
×
0
0
AND
OR
AND