GE Feeder Management Relay 750 Instruction Manual page 154

5.7 S6 MONITORING
c) ARCING CURRENT
5
PATH: SETPOINTS S6 MONITORING
ARCING CURRENT
[ENTER] for more
The relay calculates an estimate of the per-phase wear on the breaker contacts by measuring and integrating the arcing
current squared passing through the contacts while they are opening. These per-phase values are added to accumulated
totals for each phase and compared to a programmed threshold value. When the threshold is exceeded in any phase, the
relay can be used to generate an alarm. The threshold value can be set to a maintenance specification provided by the
breaker manufacturer.
For the
TOTAL ARCING CURRENT START DELAY
is issued, until the breaker contacts will actually begin to open. This setpoint is used by the relay to determine when to start
integrating. The integration continues for 100 ms, by which time most modern breakers will have cleared a fault.
For the
TOTAL ARCING CURRENT LIMIT
For example, if an alarm is desired as soon as the total arcing current in any phase exceeds 1000 kA
for this setpoint. An output will occur when the total arcing current in any phase reaches this setpoint.
Note that the total arcing current for each phase will still be available for display under
if the
RENT ARCING CURRENT FUNCTION
5-90
Courtesy of NationalSwitchgear.com
Figure 5–50: TRIP COUNTER LOGIC
EQUIPMENT ARCING CURRENT
ð
ARCING CURRENT
ENTER
ESCAPE FUNCTION: Disabled
ARCING CURRENT
ESCAPE
MESSAGE RELAYS (3-7): -----
ARCING CURRENT
ESCAPE
MESSAGE START DELAY: 32 ms
TOTAL ARCING CURRENT
ESCAPE
MESSAGE LIMIT: 1000 kA2-cyc
setpoint, enter the expected ms time delay, from the moment a trip command
, enter the total arcing current in kA
set to "Disabled".
750/760 Feeder Management Relay
Range: Disabled, Alarm, Latched Alarm, Control
Range: Any combination of 3 to 7 Auxiliary relays
Range: 0 to 100 ms in steps of 1
2
Range: 1 to 50000 kA -cyc in steps of 1
2
–cycle, at which this feature is to cause an alarm.
A3 MAINTENANCE
5 SETPOINTS
2
–cycle, enter "1000"
ARCING CUR-
GE Multilin