The Commutation Circuit Topology Of Low-voltage DC Vacuum Circuit Breaker And The Optimized Design Of The Arc Extinguishing Chamber Structure

Mechanical direct current(DC)vacuum circuit breaker(VCB)is an indispensable control and protection electrical equipment in the DC power system.It is widely used in DC power distribution system because of its fine insulation and breaking capacity,friendly medium environment and maintenance free service.Since there is no natural current zero for the direct current,the topology and parameter group design of artificial commutation circuit are the key to DC breaking and post arc dielectric recovery.In this dissertation,based on the analysis of non-dominated sorting particle swarm optimization(NSPSO)multi-objective optimization algorithm,combined with the advantages of non dominated sorting method in non-dominated sorting genetic algorithm(NSGA)and non-dominated sorting genetic algorithm2(NSGA2),an improved NSPSO algorithm is proposed and implemented by self programming.Based on the improved NSPSO algorithm,taking the 400V/20 k A low-voltage and high current mechanical DC vacuum circuit breaker as the research object,the parameter group of its commutation circuit is taken as the optimization variable,the optimization goal is to minimize the value of commutation capacitance and the precharge voltage of the commutation capacitance as much as possible at the same time,and the competition relationship between the development of the post arc sheath and the transient recovery voltage of the DC vacuum circuit breaker is taken as the constrained condition of multiple objective and multiple variable optimization.The multiple objective and multiple parameter optimization design of the commutation circuit of 400V/20 k A lowvoltage and large current DC vacuum circuit breaker is realized.Based on the Simulink platform,the simulation and analysis of the optimized commutation circuit topology are carried out.Based on the joint simulation of Solid Works 3D modeling software,COMSOL finite element simulation software and MATLAB mathematical analysis software,adopting the improved NSPSO algorithm,taking the geometric structure parameters of the key parts of the internal insulation structure in 400V/20 k A lowvoltage large current DC vacuum interrupter as the optimization variables,taking the maximum and average electric field strength of the contact area and shield area of the vacuum interrupter as much as possible at the same time as the optimization goal,based on the analysis of three-dimensional electric field of 400V/20 k A low-voltage large current DC vacuum interrupter,the optimal design of insulation structure is realized.And based on the optimization results,the distribution of electric field intensity along the surface of key components in the interrupter is analyzed and visualized.