Abstract: The simulation and structural optimization process of arc extinguishing chambers are mostly studied in isolation, considering electric or force fields, which makes it difficult to accurately characterize the dynamic behavior of arc extinguishing chambers under the coupling of multiple physical fields, resulting in poor performance of arc extinguishing chamber breaking. To this end, a multiphysics simulation and design of vacuum circuit breaker arc extinguishing chamber for smart grid was proposed. Constructed an electric field model based on Maxwell's equations, analyzed the relationship between charge and electric potential using Gaussian electric field law, and considered the induced electric field in dynamic processes using Faraday's electromagnetic induction law. Calculated electromagnetic force based on Ampere's Law, constructed an output field model, and then established a coupling relationship equation between electric field and force field parameters. A transient simulation model for bidirectional coupling of power has been established, surpassing the limitations of traditional single physical field analysis. To accurately evaluate the performance of the arc extinguishing chamber, a quantitative index of electric field uniformity and electromagnetic force stability were proposed for the first time. The commutation circuit parameter group of the circuit breaker was set as the optimization variable, and the electric field uniformity was quantified by combining the electric field strength. Then, the electromagnetic force stability was quantified by calculating the average electromagnetic force, and a multi-objective optimization function was constructed by minimizing mechanical stress. Implementing inductance and capacitance constraints, and combining non-dominated sorting particle swarm optimization (NSPSO) algorithm for collaborative optimization, using non-dominated sorting operation to update and iterate the parameter group of the converter circuit, and finally outputting the optimal structural parameter scheme for the vacuum circuit breaker arc extinguishing chamber. The results show that after simulating and optimizing the design of the arc extinguishing chamber using the proposed method, the contact wear is about 0.6 mm, which has ideal breaking performance and significantly improves the electrical life and operational reliability of the arc extinguishing chamber under short-circuit breaking conditions.

Key words: smart grid, vacuum circuit breaker, arc extinguishing chamber, multiple physical fields, NSPSO algorithm