The Interrupting Process Computation And Analyses Of A Self Extinguishing Type SF₆ Circuit Breaker

In these years, SF6 gas is widely used in the high voltage circuit breaker because of its excellent insulating and arc-quenching character .It is very meaningful to optimize the design of circuit breaker and save the expenditure of test by using the computer auxiliary computation.In this paper, The gas flow is simulated in the 252kV Self-Extinguishing Type SF6 Circuit Breaker which is being studied by the TianYing company in PingDingshan. The idea which combines the self-programmed method and the fluid computation software is presented. The interaction between the arc and the gas flow is simulated during interruption by using the idea. The state parameters of the expansion volume, the dynamic properties of arc and flow field parameters during the breaking process are obtained.The paper calculates and analyzes the influences of the initial pressure, the volume of the expansion chamber, and the throat diameter of the nozzle on the non-loaded performance of the circuit breaker, and presents the variation of the state parameters of the expansion volume and the flow field during interruption period, also predicts the nature of the self-extinguishing circuit breaker.The load performance of the circuit breaker are analyzed. The theory of the expansion volume pressure rise is predicted. Analyzing the variation of the nozzle arc parameters at current zero, In addition, analyzing the breaking property of the studied circuit breaker on the basis of the theory. The blasting circuit breaker and the studied self-extinguishing circuit breaker that are in the same voltage level are compared. It proves that the arc energy can be used to help build the pressure of the expansion chamber and extinguishing the arc in order to lessen the driven energy.