Date Code 20010731 Metering and Monitoring 6-7
SEL-352-1, -2 Instruction Manual
The expression represents a straight-line equation in a log-log plot. You need to use three
equations, because the curve has three regions and there is an equation per region. Each region
has a corresponding K and • constant derived using the (KASP1, COPS1), (KASP2, COSP2),
and (KASP3, COSP3) point pairs as follows:
Table 6.1:
a and K Constants for the Three Regions in Figure 6.1
Region 1 Region 2 Region 3
0
1
=a
()
2KASP/1KASPlog
2COSP/1COSPlog
2
=a
()
3KASP/2KASPlog
3COSP/2COSPlog
3
=a
1COSPK
1
=
()
()
2
2
1KASP
1COSP
K
a
=
()
()
3
3
2KASP
2COSP
K
a
=
Relay Word bit BCW asserts when the accumulated breaker wear for a particular phase (A, B, or
C) reaches the 100 percent level. Use this bit as an alarm to initiate breaker inspection or
maintenance.
Breaker Alarms
The relay reports the total number of breaker operation alarms for each specified alarm
condition. The BALRM setting indicates which alarms are reported. You can use the BRE S
command to display the summary and breaker alarms independent from the breaker operations.
Selecting Alarms
Select breaker alarms with the BALRM setting. The default setting shown below includes all
possible alarms. See Breaker Alarm Logic in Section 3: Breaker Logic, for default setting
descriptions and logic diagrams. Use the SET R command to set BALRM.
Use only the alarms applicable to the operations and configuration of the application. Additional
alarms will only confuse the interpretation of the report. For example, if the breaker does not
include trip and close resistors, the thermal alarms are not necessary. Do not list FTRS or FTCS
in the BALRM setting.
=>>SET R BALRM<ENTER>
Breaker Monitor
Breaker Alarm Types (24 Max)
BALRM =52ACV CWO TWO BDNC CAMT MCC ST SC PTD
?
Total Count
The count increments each time a breaker alarm condition is satisfied (rising-edge detection). If
an alarm condition persists, the counter cannot increment again. The total count resets any time
the BRE C, SET, SET R, or SET G command executes or the relay loses power.
To Next Page
