ABB RELION RET670 Applications Manual page 886

Section 18
Monitoring
880
Circuit breaker status
Monitoring the breaker status ensures proper functioning of the features within the
protection relay such as breaker control, breaker failure and autoreclosing. The breaker
status is monitored using breaker auxiliary contacts. The breaker status is indicated by
the binary outputs. These signals indicate whether the circuit breaker is in an open,
closed or error state.
Remaining life of circuit breaker
Every time the breaker operates, the circuit breaker life reduces due to wear. The wear
in a breaker depends on the interrupted current. For breaker maintenance or
replacement at the right time, the remaining life of the breaker must be estimated. The
remaining life of a breaker can be estimated using the maintenance curve provided by
the circuit breaker manufacturer.
Circuit breaker manufacturers provide the number of make-break operations possible at
various interrupted currents. An example is shown in figure 406.
1MRK 504 163-UUS A
Transformer protection RET670 2.2 ANSI
Application manual