Review of Partial Discharge Activity Considering Very-Low Frequency and Damped Applied Voltage

When detecting the presence of partial discharge (PD) activity in insulation system high-voltage equipment, excitation voltages at variable frequency have been widely used instead power-frequency (50/60 Hz) sinusoidal voltage order to reduce charging power. This work reviews relevant research on PD very low (VLF) method, including or cosine-rectangular shape, and damped AC (DAC) method. Based history development status, some major characteristics, such as inception (PDIV), amplitude, charge, phase-resolved pattern, several hot issues, surface charge decay statistical time lag, discussed. Moreover, advantages, disadvantages, applied conditions two reviewed methods has summarized. Finally, prospects made main trends this field future.