5.16
SEL-751A Relay Instruction Manual Date Code 20100129
Metering and Monitoring
Breaker Monitor
Connect the plotted points in Figure 5.17 for a breaker maintenance curve. To
estimate this breaker maintenance curve in the SEL-751A breaker monitor,
three set points are entered:
These three points are entered with the settings in Table 5.10 .
Table 5.9 Breaker Maintenance Information for a 25 kV Circuit Breaker
Current Interruption Level (kA)
Permissible Number of
Close/Open Operations
a
a
The action of a circuit breaker closing and then later opening is counted as one close/open
operation.
0.00–1.20 10,000
2.00 3,700
3.00 1,500
5.00 400
8.00 150
10.00 85
20.00 12
Set Point 1
COSP1
maximum number of close/open operations with
corresponding current interruption level.
Set Point 2
COSP2
number of close/open operations that correspond to
some midpoint current interruption level.
Set Point 3
COSP3
number of close/open operations that correspond to
the maximum current interruption level.
Table 5.10 Breaker Monitor Settings
Setting Prompt Setting Range
Setting Name :=
Factor y Defau lt
Breaker Monitor (Y,N) EBMON := Y
CL/OPN OPS SETPT 1 (0–65000) COSP1 := 10000
a
a
COSP1 must be set greater than COSP2.
CL/OPN OPS SETPT 2 (0–65000) COSP2 := 150
bc
b
COSP2 must be set greater than or equal to COSP3.
c
If COSP2 is set the same as COSP3, then KASP2 must be set the same as KASP3.
CL/OPN OPS SETPT 3 (0–65000) COSP2 := 12
kA PRI INTERRPTD 1 (0.10–999.00 kA) KASP1 := 1.20
d
d
KASP1 must be set less than KASP2.
kA PRI INTERRPTD 2 (0.10–999.00 kA) KASP2 := 8.00
kA PRI INTERRPTD 3 (0.10–999.00 kA) KASP3 := 20.00
e
e
KASP3 must be set at least five times (but no more than 100 times) the KASP1 setting value.
BRKR MON CONTROL SELOGIC BKMON := TRIP
To Next Page
Loading...
