Research on Post-arc Recovery Characteristics of Sheath in Long-Gap Vacuum Circuit Breaker

Due to the proposal of China's the goals of carbon peaking and carbon neutrality, vacuum circuit breakers have become the best choice for SF6 replacement due to their advantages of zero carbon emissions and strong breaking capacity. However, there are only 126 kV and below single-break vacuum interrupters for high-voltage transmission levels, and 252 kV vacuum interrupters have not yet been put into use for commercial products. The 252 kV level vacuum switch has the characteristics of high withstand voltage level and long contact gap distance, and its breaking capacity is closely related to the recovery process of the back-arc medium. In this paper, the Continuous Transition Model (CTM) model of the back-arc sheath is adopted, and the transient recovery voltage of the 220 kV transmission line model is input as a parameter. Parameters, the curves of the length of the sheath, the surface electric field intensity of the new cathode, and the power density with time are obtained, and the time spent in the recovery phase of the back-arc sheath, the maximum value of the surface electric field intensity, and the maximum power density are obtained, which is high voltage level, long gap vacuum circuit breaker design provides theoretical support.