Sel 751A - Figure 5.23 Breaker Monitor Accumulates 100 Percent Wear

5.23
Date Code 20100129 Instruction Manual SEL-751A Relay
Metering and Monitoring
Breaker Monitor
50 Percent to 100 Percent Breaker Wear
Refer to Figure 5.23. The current value changes from 12.0 kA to 1.5 kA. 1.5
kA is interrupted 3000 times (3000 close/open operations = 6000 – 3000),
pushing the breaker maintenance curve from the 50 percent wear level to the
100 percent wear level.
When the breaker maintenance curve reaches 100 percent for a particular
phase, the percentage wear remains at 100 percent (even if additional current
is interrupted), until reset by the BRE R command (see View or Reset Breaker
Monitor Information on page 5.24). But the current and trip counts continue to
be accumulated, until reset by the BRE R command.
Additionally, logic outputs assert for alarm or other control applications—see
the following discussion.
Figure 5.23 Breaker Monitor Accumulates 100 Percent Wear
10,000
100%
1000
2
3
4
5
6
7
8
9
100
2
3
4
5
6
7
8
9
10
2
3
4
5
6
7
8
9
123456789
50
40
30
20
10
.5
Number of Close/Open Operations
kA Interrupted per Operation
50%