Multi-objective optimization design of commutation circuit in DC vacuum circuit breaker
Modeling DC vacuum circuit breaker (DC VCB), based on Kirchhoff's law, using the method of changing high order equation into a first-order equation, combining with variable step fourth order Runge-Kutta method, the numerical calculation and analysis of DC VCB in various stages during interruption are taken. And the absolute value of the product of the decline rate of current before current zero (CZ) and the rise rate of the recovery voltage after CZ is used to measure the arc extinguishing capacity of the main circuit breaker. Moreover, the product of DC VCB commutation capacitance value and square of its rated voltage is used to evaluate the cost of DC VCB. And the post-arc vacuum dielectric recovery characteristics is considered by the sheath development based on the continuous transition model. The most reliable breaking operation, the lowest cost and the shortest sheath development time are taken as the optimization objective respectively. Using genetic algorithm (GA), the optimization of commutation circuit parameters (CCPS) is proposed. The optimization results provide reference for selecting the commutation inductance (CL) and commutation capacitor (CC), according to the commutation circuit design for different practical conditions and different requirements.