Development of a Partial Discharge Inception Calculation Model of a Nonuniform Air Gap Considering the Effect of Humidity

Insulation design employing discharge simulation based on physics phenomena is used in designing electrical instruments to facilitate their miniaturization and obtain high insulation reliability. We developed a partial discharge inception calculation model for a nonuniform air gap based on the theories of electron avalanche and streamer phenomena. The calculated and experimental PDIVs (Partial Discharge Inception Voltages) were compared under conditions of constant humidity, and we confirmed that these agreed well with each other to within about 10%. Furthermore, we incorporated a relationship between negative ions and humidity into the model and confirmed that the calculated and experimental PDIVs agreed to within about 15%. Therefore, this model was judged to be an effective method for predicting changes in the PDIV when the humidity changes. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(3): 1–9, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22351