Self-voltage sharing effects of prebreakdown current flowing through vacuum interrupters in series

To provide some theoretical and experimental bases for the development of multiple-break vacuum circuit breakers (VCB) in series, power frequency voltage breakdown tests of single and triple-break vacuum interrupter (VI) in series with a short gap length were carried out. After deriving from the test results, a phenomenon was found that the voltage distribution of each break was improved to a certain extent as the total voltage rising, and then the conclusion was proved by experimental results of power frequency voltage distribution in double-break vacuum interrupters in series. The power frequency prebreakdown current was introduced to analyze the above test phenomenon, and a self-voltage sharing effect of prebreakdown current flowing through vacuum interrupters in series was proposed. In fact, the success interruption of vacuum circuit breakers depends on transient recovery voltage (TRV). Therefore, for multiple-break vacuum circuit breakers in series, it is necessary to take some reasonable measures of voltage sharing such as shunt grading capacitors, rather than relying solely on the self-voltage sharing effects.