Partial discharge endurance life of polymer insulating materials at high temperature

This paper describes the partial discharge (PD) characteristics and V-t characteristics of several insulating materials, such as liquid crystal polymer, epoxy resins, polyimide, and polyethylene-terephthalate (PET) with a needle-plane electrode system at elevated temperature. The life index n for an applied electric field less than 20 kV/mm is found to be about 9 and that for more than 20 kV/mm is found to be less than 4. The PD characteristics of the insulating materials varied. These V-t characteristics due to PD degradation were similar to those at room temperature except for the absolute life time. (C) 1998 Scripta Technica, Elects Eng Jpn, 126(1): 15-22, 1999.