For circuit-breakers, arc modeling equations introduced by Mayr and Cassie are widely applied. The scope of them are:
Mayr arc model --- Best applicable to small current arc, in the order of less than several ten A in a SF6 gas or air-blast circuit-breaker. Also applicable to post-arc current arc which exists after the current interruption (current zero) for several ms --- called as "thermal mode." A circuit-breaker's performance in a power system, i.e., successful current breaking or not, can be best analyzed applying this arc model, because the phenomena are mainly related to such time interval. Some minor supplements to the model equation have been tried by another people.
Cassie arc model --- Best applicable to high current arc, in the order of 100A --- 100kA in a SF6 gas or air-blast circuit-breaker. Transient phenomena by damping effects of a circuit-breaker arc in a power system can be analyzed by this model, i.e., the effect of the arc resistance.
The outline and the general concepts of these models are shown in the following table.
