Development of the Partial Discharge Inception Calculation Model in a Non-uniform Air Gap Considering the Effect of Humidity

Abstract

Insulation design with discharge simulation based on physics phenomena is used in designing electrical instruments to facilitate their miniaturization and get high insulation reliability. We developed a partial discharge inception calculation model in a non-uniform air gap based on theories of electron avalanche and streamer phenomena. The calculated and experimental PDIVs were compared under a constant humidity condition, and we confirmed these agreed well with each other within about 10 %. Furthermore, we built a relationship between negative ions and humidity into the model, and confirmed the calculated and experimental PDIVs (Partial Discharge Inception Voltage) agreed within about 15 %. Therefore, this model was judged as a method for predicting changes in PDIV when the humidity changes.