Schweitzer Engineering Laboratories SEL-421-4, Instruction Manual

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8.4
SEL-400 Series Relays Instruction Manual Date Code 20171006
Monitoring
Circuit Breaker Monitor
The three set points necessary to reproduce this circuit breaker maintenance
curve in the relay are listed in
Table 8.3 for Circuit Breaker 1. Figure 8.3 shows how
to determine these three set points from the maintenance curve shown in Figure 8.2 .
10.00 85
20.00 12
Figure 8.2 Circuit Breaker Maintenance Curve (Manufacturer’s Data)
Table 8.3 Contact Wear Monitor Settings—Circuit Breaker 1
Setting Definition Range
B1COSP1 Close/open set point 1—max 0–65000 close/open operations
B1COSP2 Close/open set point 2—mid 0–65000 close/open operations
B1COSP3 Close/open set point 3—min 0–65000 close/open operations
B1KASP1
a
a
The ratio of settings B1KASP3/B1KASP1 must be in the range: 5

B1KASP3/B1KASP1

100.
kA interrupted set point 1—min 1.0–999 kA in 0.1-kA steps
B1KASP2 kA interrupted set point 2—mid 1.0–999 kA in 0.1-kA steps
B1KASP3
a
kA interrupted set point 3—max 1.0–999 kA in 0.1-kA steps
Table 8.2 Circuit Breaker Maintenance Information—Example (Sheet 2 of 2)
Current Interruption Level (kA) Permissible Close/Open Operations
1 10 100
kA Interrupted per Operation (kA)
Number o
f Close
/Open Oper
ations
10000
1000
100
10