Aging Time Effect on PD Characteristics under Continuous Pulse Voltage

The electrical characteristic of twisted pair specimen for high-power inverter-fed motor has been addressed through aging tests under PWM-like voltage waveform in this paper. Partial discharge (PD) parameters (e.g., phase resolved PD pattern, skewness) for twisted pair specimens at different aging time are investigated in order to show the relationship between PD parameters and aging time. Comparing PD activity at pulse voltage and 50 Hz AC voltage, it is concluded that memory effect of charge and fast rise time has a larger effect on PD activity. In addition, it has been observed that independent discharge clusters present at pulse voltage with the increase of aging time, and skewness of specimens decreases after several aging time periods. These conclusions benefit for study on aging mechanism under PWM voltage further.