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

This paper describes the gas flow properties in the arc chamber and the die lectric recovery after current zero in a self-extinguishing type SF6 circui t breaker during small current interruption. First, employing the modified fluid-in-cell method and the movable mesh technique, the gas flow character istic in the arc chamber is calculated during the small current interruptio n, and secondly, the static electrical field is computed by using the finit e element method. Combined with the calculation of above, this paper calcul ates the dielectric strength recovery after current zero and estimates the capability of small current interruption using the streamer theory of gas b reakdown.