Investigations of prestriking and current chopping in medium voltage SF6 rotating arc and vacuum switchgear

Prestriking overvoltages and current chopping levels of SF₆ rotating arc switching devices are examined. Experiments have been carried out to determine the effects of circuit configurations on prestriking and current chopping. These results are compared with those of other switching media obtained under identical conditions. The prestriking overvoltages of the contactor were found to be restricted by its high-frequency current interruption capability and dielectric recovery rate. The dielectric recovery profile also restricted the magnitude of subsequent prestrike overvoltages to values smaller than the first transient. Current chopping levels increased with parallel capacitance