Analysis of the Influence of Arc Contact Ablation and Arcing Time on the Gas Flow Characteristics of SF ₆ Circuit Breakers

High‐current interruptions aggravate arc contact ablation, and arcing time strongly influences the gas‐blast capability of self‐energy SF 6 circuit breakers. This study quantifies the effect of arcing time on gas flow characteristics while accounting for cumulative arc contact ablation over repeated operations. A T100a test is performed on a 40.5 kV/31.5 kA self‐energy SF 6 circuit breaker, and an enthalpy‐flow model is established and validated against measurements. Numerical analyses are then conducted for 1–11 interruption operations. The pressure in the expansion chamber at the current zero crossing ( P cz ) increases first and then decreases with increasing arcing time, and longer arcing times lead to a larger P cz drop after repeated operations. After 11 operations, P cz decreases by 52.14% at 22.5 ms ( τ = 75 ms) and by 60.33% at 23.9 ms ( τ = 120 ms). The P cz drop percentage exhibits a quadratic dependence on arc energy, with fitted coefficients increasing with operation count. Overall, an arcing time window of 9.6–20 ms provides the best compromise between interruption margin and cumulative degradation in this study.