Determination of Dominant Influencing Factors on Partial Discharge Inception Voltage

With the increasing interest in adopting higher DC link voltage and fast switching devices in electric drives for electrified transportation, the partial discharge (PD) risk of electrical machines boosts compromising the drive integrity. The PD inception mechanism is simultaneously affected by both ambient conditions and voltage characteristics. By determining the dominant influencing factor on partial discharge inception voltage (PDIV), the preliminary reliability assessment would be made easier since the impact of secondary factors could be temporarily neglected. In this paper, the influence of three environmental conditions (i.e., pressure, temperature, and relative humidity) and three voltage characteristics parameters (i.e., rise time, switching frequency, and duty cycle) on PDIV is studied. The results suggest that PDIV is most influenced by environmental conditions while the characteristics of test voltage have less impact on PDIV.