8.4
SEL-311C Relay Instruction Manual Date Code 20060320
Breaker Monitor and Metering Functions
Breaker Monitor
Breaker Monitor
Setting Example
The following settings are made from the breaker maintenance information in
Table 8.1 and Figure 8.1:
COSP1 = 10000
COSP2 = 150
COSP3 = 12
KASP1 = 1.20
KASP2 = 8.00
KASP3 = 20.00
Figure 8.2 shows the resultant breaker maintenance curve.
Breaker Maintenance Curve Details
In Figure 8.2, note that set points KASP1, COSP1 and KASP3, COSP3 are set
with breaker maintenance information from the two extremes in Tabl e 8. 1 and
Figure 8.1.
In this example, set point KASP2, COSP2 happens to be from an in-between
breaker maintenance point in the breaker maintenance information in
Table 8.1 and Figure 8.1, but it does not have to be. Set point KASP2, COSP2
should be set to provide the best “curve-fit” with the plotted breaker
maintenance points in Figure 8.1.
Each phase (A, B, and C) has its own breaker maintenance curve (like that in
Figure 8.2), because the separate circuit breaker interrupting contacts for
phases A, B, and C do not necessarily interrupt the same magnitude current
(depending on fault type and loading).
Table 8.2 Breaker Monitor Settings and Settings Ranges
Setting Definition Range
COSP1 Close/Open set point 1—maximum 0–65000 close/open operations
COSP2 Close/Open set point 2—middle 0–65000 close/open operations
COSP3 Close/Open set point 3—minimum 0–65000 close/open operations
KASP1
a
a
The ratio of settings KASP3/KASP1 must be: 5 ≤ KASP3/KASP1 ≤ 100.
kA Interrupted set point 1—minimum 0.00–999.00 kA in 0.01 kA steps
KASP2 kA Interrupted set point 1—middle 0.00–999.00 kA in 0.01 kA steps
KASP3
a
kA Interrupted set point 1—maximum 0.00–999.00 kA in 0.01 kA steps
BKMON SEL
OGIC
®
control equation breaker
monitor initiation setting
Relay Word bits referenced
in Table 9.5 and Table 9.6
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