Research on dynamic ablative behavior of contact during breaking of DC circuit breaker

During the circuit breaker’s breaking process, an arc is generated, which exerts an ablative effect on the contacts and significantly impacts the electrical life of the circuit breaker. Therefore, studying the ablation mechanism of arcs is crucial for enhancing the breaking performance and extending the electrical life of circuit breakers. To investigate the ablation effect of arcs on contacts, a double-break DC circuit breaker model was developed. Utilizing magnetohydrodynamics theory, FLUENT software was employed to simulate the arc motion, establish the energy balance equation for arcing and contacts, analyze the ablation mechanism during arc ignition, and calculate the mass loss of contacts during a single arc event. An experimental platform was established to conduct electrical life tests on the circuit breaker. The ablation mass loss was measured through these tests. The results indicate that under identical breaking conditions, the experimental outcomes align with the simulation results. Building on this, the influence of the breaker’s breaking speed on contact ablation was examined. Simulation results reveal that the arc ablation at the end of the contact is most severe during the combustion process, and as the breaking speed increases, the extent of arc ablation on the contact gradually diminishes.