8.18
SEL-311C Relay Instruction Manual Date Code 20060320
Breaker Monitor and Metering Functions
Station DC Battery Monitor
Station DC Battery Voltage Dips During Circuit Breaker Tripping
Event reports are automatically generated when the TRIP Relay Word bit
asserts (TRIP is the logic output of Figure 5.1). For example, output contact
OUT101 is set to trip:
OUT101 = TRIP
When output contact OUT101 closes and energizes the circuit breaker trip coil,
any change in station dc battery voltage can be observed in column
Vdc in the
event report.
To generate an event report for external trips, make connections similar to
Figure 8.8 and program optoisolated input IN106 (monitoring the trip bus) in
the SEL
OGIC control equation event report generation setting, e.g.:
ER = /IN106 + ...
When the trip bus is energized, any change in station dc battery voltage can be
observed in column
Vdc in the event report.
Station DC Battery Voltage Dips During Circuit Breaker Closing
To generate an event report when the SEL-311C closes the circuit breaker,
make the SEL
OGIC control equation event report generation setting:
ER = /OUT102 + ...
In this example, output contact OUT102 is set to close:
OUT102 = CLOSE (CLOSE is the logic output of Figure 6.1)
When output contact OUT102 closes and energizes the circuit breaker close coil,
any change in station dc battery voltage can be observed in column
Vdc in the
event report.
This event report generation setting (ER = /OUT102 + ...) might be made just
as a test setting. Generate several event reports when doing circuit breaker
close testing and observe the “signature” of the station dc battery voltage in
column
Vdc in the event reports.
Station DC Battery Voltage Dips Anytime
To generate an event report whenever there is a change in station dc battery
voltage dip, set the dc voltage element directly in the SEL
OGIC control
equation event report generation setting:
ER = \SV4T + ...
Timer output SV4T is an example dc voltage element from the bottom of
Figure 8.10. Any time dc voltage falls below pickup DCHIP, timer output
SV4T drops out (logical 1 to logical 0 transition), creating a falling-edge
condition that generates an event report.
Also, the Sequential Event Recorder (SER) report can be used to time-tag
station dc battery voltage dips (see Sequential Events Recorder (SER) Report
on page 12.28).
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