Effect Analysis of Velocity Characteristic on Breakdown Endurance Performance for DC Vacuum Circuit Breaker

For the mechanical DC vacuum circuit breaker, the velocity characteristic of the actuating mechanism will directly influence the breaking capacity and reliability of the circuit breaker. In this paper, a 10 kV/5 kA DC vacuum circuit breaker is taken as the research object to establish a post-arc sheath development model, and the post-arc breakdown endurance performance under the field-circuitry coupling effect of the electromechanical system is obtained. A non-intrusive polynomial chaos expansion model is established according to the relationship between the velocity of the actuating mechanism and the breakdown endurance performance, and the probability distribution of breakdown under the uncertainty of the velocity of the mechanism in the electromechanical coupling system is analyzed.