Sel 751A - Breaker Monitor Output; Via Front Panel; Via Serial Port; View or Reset Breaker Monitor Information

5.24
SEL-751A Relay Instruction Manual Date Code 20100129
Metering and Monitoring
Breaker Monitor
Breaker
Monitor Output
When the breaker maintenance curve for a particular phase (A, B, or C)
reaches the 100 percent wear level (see Figure 5.23), a corresponding Relay
Word bit (BCWA, BCWB, or BCWC) asserts.
EXAMPLE 5.1 Example Applications
These logic outputs can be used to alarm:
OUT
xxx = BCW
or drive the relay to lockout the next time the relay trips:
79DTL = TRIP AND BCW
View or Reset
Breaker Monitor
Information
Accumulated breaker wear/operations data is retained if the relay loses power
or the breaker monitor is disabled (setting EBMON = N). The accumulated
data can only be reset if the BRE R command is executed (see the following
discussion on the BRE R command).
Via Serial Port
See Section 7: Communications. The BRE command displays the following
information:
➤ Accumulated number of relay initiated trips
➤ Accumulated interrupted current from relay initiated trips
➤ Accumulated number of externally initiated trips
➤ Accumulated interrupted current from externally initiated trips
➤ Percent circuit breaker contact wear for each phase
➤ Date when the preceding items were last reset (via the BRE R
command)
See Section 7: Communications. The BRE W command allows the trip
counters, accumulated values, and percent breaker wear to be preloaded for
each individual phase.
The BRE R command resets the accumulated values and the percent wear for
all three phases. For example, if breaker contact wear has reached the 100
percent wear level for A-phase, the corresponding Relay Word bit BCWA
asserts (BCWA = logical 1). Execution of the BRE R command resets the
wear levels for all three phases back to 0 percent and consequently causes
Relay Word bit BCWA to deassert (BCWA = logical 0).
Via Front Panel
The information and reset functions available via the previously discussed
serial port commands BRE and BRE R are also available via the front-panel.
See Section 8: Front-Panel Operations for details.
Relay Word Bits Definition
BCWA Phase A breaker contact wear has reached the 100 percent wear level
BCWB Phase B breaker contact wear has reached the 100 percent wear level
BCWC Phase C breaker contact wear has reached the 100 percent wear level
BCW BCWA or BCWB or BCWC