Investigations on the Thermal Interrupting Capability of A Self-blast Type SF6 Circuit Breaker

Abstract

It is a complex issue for predicting the thermal interrupting capability of a circuit breaker from the simulations, lots of discussions have been going on at home and aboard, and more requirements seem to be proposed for its engineering applications in modern stages. In this paper, an interruption simulation model for 252kV self-blast SF6 circuit breaker is built according to the MHD theory. The interruption process are simulated, and the variation characteristics of gas pressure, temperature, velocity are obtained at current passing zero. With several experimental verification provided, including success and failure results, simulation and experiment results are compared. The arc conductance (G200, G300, G500) at 200ns, 300ns, 500ns before current zero for various arcing times, power frequencies and breaker samples are computed by present method. Much attention is paid to the comparisons of G200, G300 and G500. Results show that the G200 can be used as an indicator for predicting the thermal interruption capability and the investigations in this paper can be a benefit for the design of SF6 circuit breakers.