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8.18
SEL-400 Series Relays
Instruction Manual
Date Code 20171006
Monitoring
Circuit Breaker Monitor
BREAKER Command
Use the
BRE
command to access vital information about the condition of substa-
tion circuit breakers and preset or reset circuit breaker monitor data. The relay
monitors two separate circuit breakers; you must specify Circuit Breaker 1 and
Circuit Breaker 2 for most
BRE
commands.
shows the
BRE
com-
mands. For more information on the
BRE
command, see
.
The
BRE
n
C
command resets the accumulated circuit breaker monitor data for
Circuit Breaker
n
. The clear command
BRE C A
clears all data for both circuit
breakers.
The
BRE
n
command displays the circuit breaker report for the most recent Cir-
cuit Breaker
n
operation.
You can also reset the circuit breaker report with Global SEL
OGIC
setting
RST_BK
n
for the Circuit Breaker
n
report. You must first set EDRSTC (Data
Reset Control) to Y to access these Global settings.
The relay also displays the operation summary and the circuit breaker alarms.
When the circuit breaker maintenance curve reaches 150 percent for a particular
pole, the percentage wear for this pole remains at 150 percent (even if additional
current is interrupted) until reset. However, the relay continues to advance the
operation counter to as many as 9999999 operations per pole until reset. Accu-
mulated circuit breaker wear/operations data are retained if the relay loses power
or if the circuit breaker monitor is disabled (EB
n
MON := N).
The control voltage for this example is 125 Vdc. Control Input IN207 is
located on the relay I/O Interface board #1.
The recharge time measurement for this circuit breaker was 20 seconds; add
20 percent (4 seconds) to give an alarm time of 24 seconds. To set the motor
running time alarm threshold at 24 seconds, enter the following settings:
EB1MON :=
Y
Breaker 1 Monitoring (Y, N)
B1MRTIN :=
IN207
Motor Run Time Control Input—BK1 (SEL
OGIC
Equation)
B1MRTAT :=
24
Motor Run Time Alarm Threshold—BK1 (1–9999
seconds)
Assertion of the Relay Word bit B1MRTAL indicates the following condi-
tion: motor running time exceeds 24 seconds because IN207 was asserted for
more than 24 seconds.
Example 8.10
Motor Running Time Settings (Continued)
Table 8.6
BRE Command
Command
Description
Access Level
BRE C A
Clear all circuit breaker monitor data to zero.
B, P, A, O, 2
BRE
n
C
a
a
n
is the breaker reference.
Clear Circuit Breaker
n
data to zero.
B, P, A, O, 2
BRE
n
Display the breaker report for the most recent Circuit
Breaker
n
operation.
1, B, P, A, O, 2
BRE
n
H
Display history data for the last 128 Circuit Breaker
n
operations. 1, B, P, A, O, 2
BRE
n
P
Preload previously accumulated Circuit Breaker
n
data.
B, P, A, O, 2
Summary of Contents for SEL-421-4
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