Intelligent optimization of vacuum circuit breaker closing speed

The dynamic welding of vacuum circuit breakers (VCB) during the short circuit current making process can have a large impact on its performance. It has been shown that the dynamic welding of contacts is affected by the closing speed. To study the influence of the closing speed on the arc energy in the closing process, the experimental investigation and the theoretical analysis were conducted in this paper. Firstly, the relationship between the pre-breakdown voltage and the breakdown gap distance during the closing process was studied through experiments. Then a kinematic model for the vacuum circuit breaker was constructed, with considering the electromagnetic force generated by the current flowing through the contacts. The coefficient of restitution was used to describe the motion of the moving contact before and after the collision, the bouncing characteristics were simulated. Ultimately, an intelligent optimization algorithm was adopted to obtain the optimal closing speed by minimizing the total arc energy generated by the vacuum arc during the closing process including pre-breakdown arc and close bouncing arc.