Research on Breaking Conditioning Method of Vacuum Interrupter Based on Multiple Re-Strikes

The breaking conditioning of the vacuum interrupter has a certain effect on improving the withstand voltage level of the vacuum interrupter and the post-arc insulation recovery, which is crucial for successfully switching capacitor banks in 12kV vacuum interrupter. This paper introduces a dynamic breaking conditioning test method for vacuum interrupter chambers based on the competitive relationship between the rate of recovery voltage rise applied across the contacts of the vacuum circuit breaker and the rate of recovery of the gap insulation. By inducing multiple consecutive re-strike on the contact surface during the breaking process, weak points on the contact surface are eliminated, leading to a gradual increase in dielectric recovery strength. The re-strike waveforms at different rise times of the gap are obtained by building a simulation platform. The dynamic breaking conditioning test platform of vacuum interrupter is built, in which the average speed of contact opening is 0.89 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$m$</tex>/s, the rising time of gap recovery voltage is 0.5 ms, and the breaking voltage is 40 kV. The test results show that during the breaking process of the interrupter, there will be multiple re-strikes, and then continuous electric spark conditioning occurs on the surface of the contact. The anti-re-strike performance is improved: the number of re-strikes decreases and the withstand voltage level increases. According to the re-strike waveform, the vertex envelope of the re-strike waveform of the vacuum interrupter can be obtained, and the performance change trend of the vacuum interrupter can be judged by this envelope.