Ground Fault - GE 469 Instruction Manual

CHAPTER 5: SETTINGS
Note
5.7.6

Ground Fault

FAULT
469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL
unbalances are common, a reasonable delay should be set to avoid nuisance trips or
alarms. The unbalance bias feature is recommended to bias the thermal model for motor
heating caused by cyclic short term unbalances (see page –54 for details).
Unusually high unbalance levels may be caused by incorrect phase CT wiring.
For example, fluctuations of current unbalance levels are typically caused by the supply
voltage. It may be desirable to have a latched alarm to capture any such fluctuations that
go beyond the Unbalance Alarm parameters. Also, a trip is recommended.
If the supply voltage is normally unbalanced up to 2%, the current unbalance seen by a
typical motor is 2 × 6 = 12%. In this case, set the
"15" and the
CURRENT UNBALANCE TRIP PICKUP
10 seconds is a reasonable delay.
PATH: SETTINGS S6 CURRENT ELEM.
GROUND
[ ]
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
CURRENT UNBALANCE ALARM PICKUP
to "20" to prevent nuisance tripping; 5 or
GROUND FAULT
GROUND FAULT
OVERREACH FIL-
GROUND FAULT
ALARM: Off
ASSIGN ALARM
RELAYS:
GROUND FAULT
ALARM
INTENTIONAL GF
ALARM
GROUND FAULT
ALARM
GROUND FAULT
TRIP: Off
ASSIGN TRIP
RELAYS:
GROUND FAULT TRIP
PICKUP: 0.20 x CT
INTENTIONAL GF
TRIP
GROUND FAULT TRIP
BACKUP: Off
ASSIGN BACKUP
RELAYS:
Range: On, Off
Range: Off, Latched, Unlatched
Range: Alarm, Alarm & Auxiliary2,
Alarm & Aux2 & Aux3,
Auxiliary2, Aux2 & Aux3,
Auxiliary3
Range: 0.1 to 1.00 x CT in steps of 0.01
or 0.25 to 25 A in steps of 0.01
Range: 0 to 1000 ms in steps of 1
Range: On, Off
Range: Off, Latched, Unlatched
Range: Trip, Trip & Auxiliary2, Trip &
Aux2 & Aux3, Trip & Auxiliary3,
Auxiliary2, Aux2 & Aux3,
Auxiliary3
Range: 0.1 to 1.00 x CT in steps of 0.01
or 0.25 to 25 A in steps of 0.01
Range: 0 to 1000 ms in steps of 1
Range: On, Off
Range: Auxiliary2, Aux2 & Aux3,
Auxiliary3
to
5–63