ABB RELION 670 Series Applications Manual page 206

Section 7
Current protection
tMin_HOL_IDMT = 0.1s ; Minimum time delay for IDMT stage. Selected value gives operate time in
accordance with international standards
7.10.3.1 Restrike detection
Opening of SCBs can be quite problematic for certain types of circuit breakers (CBs). Typically
such problems are manifested as CB restrikes.
In simple words this means that the CB is not breaking the current at the first zero crossing after
separation of the CB contacts. Instead current is re-ignited and only braked at consecutive current
zero crossings. This condition is manifested as high current pulses at the moment of current re-
ignition.
To detect this CB condition, the built in overcurrent feature can be used. Simply, any start of the
overcurrent feature during breaker normal opening means a restrike. Therefore simple logic can be
created in the Application Configuration tool to detect such CB behavior. Such CB condition can be
just alarmed, and if required, the built in disturbance recorder can also be triggered.
To create this logic, a binary signal that the CB is going to be opened (but not trip command) shall
be made available to the IED.
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Application manual