Calculation Method and Influencing Factors of the Maximum Breaking Current of SF6 Circuit Breaker

SF
6
circuit breaker arc simulation lacks research on the evaluation of circuit breaker's maximum breaking current ability. Therefore, a coupling simulation model of electromagnetic, thermal, fluid and radiation physical fields was established for circuit breaker breaking process. A breaking criterion based on temperature distribution was proposed to study the changing law of circuit breaker's maximum breaking current on the basis of mutual verification with traditional criteria. It is found that the ablation angle of the contact decreases the maximum breaking current ability of the circuit breaker rapidly. For 126 kV circuit breaker, the maximum ablation angle of the contact to achieve the rated working condition is 12~13° at the intact angle of the contact. The maximum breaking current capacity of the circuit breaker corresponding to the opening speed within the standard range of the circuit breaker speed is basically unchanged, and the maximum breaking current capacity below the speed standard range is greatly reduced. The research results will provide a theoretical basis for SF
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circuit breaker engineering to break short circuit current.