Study on Key Influencing Factors of Circuit Breaker Breaking Capacity

During the interruption process of a circuit breaker, the interaction between the arc and the high-speed airflow within the pneumatic cylinder critically influences the arc extinguishing effect. Simultaneously, the establishment of the flow field within the extinguishing chamber is crucially dependent on the design parameters of the nozzle. However, with the increasing presence of DC components, peak breaking current, and energy, an urgent need arises for a viable optimization strategy for the nozzle structure. To address this challenge, we conducted finite element analysis of the nozzle structure and proposed corresponding optimization strategies to enhance the reliability of short-circuit current interruption in the extinguishing chamber. Simulation analysis results reveal that the diameter of the nozzle throat directly impacts the arc quenching effect and breaking performance, while the expansion angle downstream of the nozzle plays a vital role in the recovery speed of dielectric within the zero-point post-arc gap.