Investigation of Dielectric Recovery Characteristiics of Hot SF6 Gas After Current Interruption for Developing New 300 kV and 550 kV Gas Circuit Breakers

The analysis of the electrical breakdown phenomenon in hot SF6 gas is of practical importance for designing circuit breakers. It is studied both in experimental and theoretical method. A simplified method is proposed to estimate the withstand voltage of the gap in hot gas stream. The gas temperature of the stream is evaluated by the simulation method formerly proposed by Kuwahara et al. [4]. The result of this simulation showed a. good agreement with the experimental results. The breakdown during the process of the voltage recovery after current interruption is numerically calculated by this simulation process and is compared with the experimental results.