Research on Flow Distribution Characteristics in Circuit Breaker Breakdown Process Based on Schlieren Method
Circuit breakers will be broken again under the influence of multiple lightning strikes after tripping,which reduces the life of circuit breakers and threatens the stable operation of the power system.To address this problem,the paper obtained the temperature diffusion process of circuit breaker opening impact current process by ripple shadow method,combined with the existing image recognition technology to obtain the temperature characteristics of the airflow in the contact air gap,airflow flow characteristics.The research results show that the shockwave velocity during circuit breaking is approximately equivalent to the speed of sound under similar conditions.The maximum boundary diffusion velocity of the airflow is about one-fourth of the speed of sound under similar conditions and decays rapidly,reducing to the drift velocity of the airflow within 10 ms after the circuit is broken.The maximum temperature of the thermal airflow concentrates between 6 000～8 000 K,with temperature changes approximately inversely proportional to the square of time.The study provides a basis for circuit breaker contact structure design,opening speed optimization method,interrupter chamber and insulation design optimization.
gas insulatedschlieren methodplasmacontact structurebreakdownairflow
万方数据
维普
