Approximation Model-Assisted Optimization Technique to Improve Capacitive Current Interrupting Performance of Gas Circuit Breaker

This paper presents the optimal design of a SF₆ gas circuit breaker to improve the capacitive current interrupting performance. The objective function for the optimization is the minimal difference between the breakdown voltage and the applied voltage. To obtain the dynamic gas properties, the axisymmetric Euler equation is solved using the finite volume fluid in cell method. Breakdown voltage is calculated using the empirical equation, which is a function of the gas density and the electric field intensity. To facilitate the optimization process, which is computationally intensive, the Kriging model is employed as an approximation model. A sequential approximation technique is developed to improve the accuracy of the Kriging model and to reduce the number of real function calls. The developed optimization technique was applied to the design of a 145-kV gas circuit breaker. It was verified that the optimized circuit breaker has better interrupting performance than the original model.