Schweitzer Engineering Laboratories SEL-351A - Figure 8.2 SEL-351 A Breaker Maintenance Curve for a 25 Kv Circuit Breaker

8.5
Date Code 20080213 Instruction Manual SEL-351A Relay
Breaker Monitor and Metering
Breaker Monitor
Figure 8.2 SEL-351A Breaker Maintenance Curve for a 25 kV Circuit Breaker
In Figure 8.2, note that the breaker maintenance curve levels off horizontally
below set point KASP1, COSP1. This is the close/open operation limit of the
circuit breaker (COSP1 = 10000), regardless of interrupted current value.
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
KASP1 = 1.2
COSP1 = 10000
KASP2 = 8.0
COSP2 = 150
KASP3 = 20.0
COSP3 = 12
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