Study on Characteristics of Partial Discharge in XLPE Cable under Damped AC Voltage at Different Frequencies

Damped AC (DAC) voltage method is widely used in partial discharge (PD) detection of power cable. The frequency of DAC voltage is changed due to different length of testing cable. To study the PD characteristics in the heat-shrinkable cable accessories under DAC voltage at different frequencies, four different cases of artificial defects in cross-linked polyethylene (XLPE) cables were investigated. These defects include termination without stress tube, incorrect use of insulation tape as the semi-conductive adhesive tape in the middle joint, void and metal particles on the surface of XLPE insulation. Furthermore, some characteristic PD parameters including the partial discharge inception voltage (PDIV), the partial discharge extinction voltage (PDEV), discharge magnitude, discharge times and so on were compared and analyzed. The results show that PD characteristics are different as the DAC frequency changes, which provides guidance for the practical application.