Schweitzer Engineering Laboratories SEL-700G Series, Инструкция по эксплуатации, Страница: 364 / 824

5.20
SEL-700G Relay Instruction Manual Date Code 20170814
Metering and Monitoring
Breaker Monitor
Note in Figure 5.20 through Figure 5.23 that the interrupted current in a given
figure is the same magnitude for all interruptions (for example, in Figure 5.21,
2.5 kA is interrupted 290 times). This is not realistic, but it demonstrates the
operation of the breaker maintenance curve and how it integrates for varying
current levels.
0 Percent to 10 Percent Breaker Wear
Refer to Figure 5.20. 7.0 kA is interrupted 20 times (20 close/open
operations = 20 – 0), pushing the breaker maintenance curve from the
0 percent wear level to the 10 percent wear level.
Compare the 100 percent and 10 percent curves. Note that for a given current
value, the 10 percent curve has only 1/10 of the close/open operations of the
100 percent curve.
Figure 5.20 Breaker Monitor Accumulates 10 Percent Wear
10,000
100%
10%
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
1 2 3 4 5 6 7 8 9
50 40 30 20
10 .5
Number of Close/Open Operations
kA Interrupted per Operation