Sel 751A, Инструкция по эксплуатации

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5.21
Date Code 20100129 Instruction Manual SEL-751A Relay
Metering and Monitoring
Breaker Monitor
10 Percent to 25 Percent Breaker Wear
Refer to Figure 5.21 . The current value changes from 7.0 kA to 2.5 kA. 2.5 kA
is interrupted 290 times (290 close/open operations = 480 – 190), pushing the
breaker maintenance curve from the 10 percent wear level to the 25 percent
wear level.
Compare the 100 percent and 25 percent curves and note that for a given
current value, the 25 percent curve has only 1/4 of the close/open operations
of the 100 percent curve.
Figure 5.21 Breaker Monitor Accumulates 25 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
25%