ABB REB670 Applications Manual page 422

Section 14
Monitoring
416
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 Figure179.
1MRK 505 337-UUS -
Application manual