The Interrupting Capability Computation And Analyses Of 252kV Self-extinguishing Type SF6 Circuit Breaker

In this paper, associated with the key problem of 252kV self-extinguishing SF6 high voltage circuit breaker which is used in PingDingShan, the mathematical models of static electrical field and one-dimensioned and two-dimensioned gas flow field during the overall breaking procession arc chamber of circuit breaker are developed. So it is very practical in engineering.Integrated the requirement of developing the self-extinguishing type SF6 circuit breaker, this paper performed theoretical calculation and numerical analysis on the mechanic performance, electric and gas-flow fields distribution of the circuit breaker, and provided a theoretical basis for the development of The self-extinguishing type SF6 circuit breaker.At first, the electric field distribution in the chamber of the breaker was calculated with the help of ANSYS program, and then the inner structure and porcelain of the chamber was optimized according to the calculated results and verified through tests. During the calculation of gas-flow field, aimed at concrete structure model studied, a mathematical model for gas-flow field was worked out with FORTRAN and PHOENICS language. With this program, calculated the gas flow properties in the chamber during the short-current interruption. The feature that gas pressure, speed and density in gas-flow field distribute with time and space. And finally, the law of gas flow in chamber under small-current condition was got. The structure parameters were changed to analyze the influence of the change of structure parameters on gas flow feature under small-current condition.The load performances 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 thebasis of the theory. 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.