Numerical calculation of interruption properties of the self-extinguishing type SF6 circuit breaker during small current interruption

This paper describes the gas flow properties in the arc chamber and the dielectric recovery after current zero in a self-extinguishing type SF₆ circuit breaker during small current interruption. First, employing the modified fluid-in-cell method and the movable mesh technique, the gas flow characteristic in the are chamber is calculated during the small current interruption, and secondly, the static electrical field is computed by using the finite element method. Combined with the calculation of above, this paper calculates the dielectric strength recovery after current zero and estimates the capability of small current interruption using the streamer theory of gas breakdown