SF6 Dynamic Capacitance Measurement Methods for Breaks in the Breaking Process of Circuit Breakers

In order to effectively obtain the contact state without disassembling the interrupter chamber of the SF6 circuit breaker, a dynamic capacitance measurement method for the breakout process of the circuit breaker is proposed. The dynamic capacitance measurement is carried out by applying high-frequency excitation at both ends of the interrupter chamber, the dynamic capacitance measurement system that can meet the pF-level variation is designed, and the measurement method for correcting the stray capacitance of the wire is proposed. Based on the fundamental wave component method, a dynamic capacitance calculation method is proposed for the circuit breaker tripping process, and the optimal parameter combination for the dynamic capacitance calculation is determined through simulation analysis. The best combination of computational parameters for dynamic capacitance calculations was determined to be a triangular window, a window length of 480, and an overlap length of 0. The dynamic capacitance-travel curve of SF6 circuit breaker tripping process under different ablation states is obtained in the final test, and the results show that: with the increase in contact ablation, the overall shape of the dynamic capacitance-travel curve is basically unchanged, and the capacitance value at the starting point increases and the travel value decreases, which provides a new idea for the evaluation of circuit breaker interrupter chamber’s electric life. This provides a new idea for the electrical life assessment of circuit breaker interrupters.