Partial Discharge Behaviors of Surface Modified Polyimide Films in Liquid Nitrogen

The development of high temperature superconducting technology promotes the research and development of the HTS cable in recent years. Due to excellent dielectric properties of polyimide (PI) film at cryogenic temperature, PI film has been used as electrical insulation of the HTS cable. Lots of studies were focused on the surface flashover and insulation breakdown properties of the PI in room temperature condition, however the direct-fluorinated performance in liquid nitrogen environment was not clear. In this paper, the partial discharge inception voltage, the surface partial discharge number, the average discharge voltage amplitude was carried out. The result showed that the fluorinated layer can reduce the amount of partial discharge on the sample surface.