The purpose of the circuit breaker operation monitoring subfunction is to indicate if the circuit breaker has not been operated for a long time.
The operation of the circuit breaker operation monitoring can be described with a module diagram. All the modules in the diagram are explained in the next sections.
Inactivity timer
The module calculates the number of days the circuit breaker has remained inactive, that is, has stayed in the same open or closed state. The calculation is done by monitoring the states of the POSOPEN and POSCLOSE auxiliary contacts.
The inactive days INA_DAYS is available in the monitored data view. It is also possible to set the initial inactive days with the Ini inactive days parameter.
Alarm limit check
When the inactive days exceed the limit value defined with the Inactive Alm days setting, the MON_ALM alarm is initiated. The time in hours at which this alarm is activated can be set with the Inactive Alm hours parameter as coordinates of UTC. The alarm signal MON_ALM can be blocked by activating the binary input BLOCK.