Discussions on post arc current of a CO2 circuit breaker

It has been observed in our tests that the post arc current near the breaking limit of a CO₂ circuit breaker is 10 A or more, and the post arc current of a SF₆ circuit breaker is approximately 0.3 A. We explain this major difference in the post arc current with calculations using two serially-connected arc models. We prove that the arc characteristic of a relatively longer time domain up to the extinction peak for a CO₂ circuit breaker and that of a short time domain from the extinction peak until the current zero point for a SF₆ circuit breaker have great effects on breaking performance.