Study on Flashover Characteristics of Epoxy Resin and Polytetrafluoroethylene Under DC Voltage

The main components of resistive type DC superconducting fault current limiter (R-DCSFCL) are the current limiting unit and the electrical terminal, in which the insulating material used in cryogenic zone is mainly glass fiber reinforced epoxy resin and polytetrafluoroethylene. In this paper, insulation performance of epoxy resin and polytetrafluoroethylene samples in liquid nitrogen is studied. The effect of different electrode types, different creep distance and different flashover times on the flashover voltage of test sample in liquid nitrogen is investigated. Further, the test result is analyzed with Weibull distribution. The results show that the flashover voltage of G10 and PTFE is related to the electrode types and creep distance, and the secondary flashover voltage of G10 is significantly lower than the initial flashover voltage, which can be used as the theoretical basis for the design of low-temperature insulation for R-DCSFCL.