8-12
Breaker Monitor and Metering Functions
Date Code 20011205
SEL-311A Instruction Manual
Breaker Monitor Output
When the breaker maintenance curve for a particular phase (A, B, or C) reaches the 100 percent
wear level (see Figure 8.7), a corresponding Relay Word bit (BCWA, BCWB, or BCWC) asserts.
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 + BCWB + BCWC
Example Applications
These logic outputs can be used to alarm:
OUT105 = 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
BRE Command (Breaker Monitor Data)
in
Section 10: Serial Port Communications and
Commands
. 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
BRE n Command (Preload/Reset Breaker Wear)
in
Section 10: Serial Port
Communications and Commands
. The
BRE W
command allows the internal trips and currents,
the external trips and currents, and the 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).
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