Partial Discharge Behavior in a Loaded HVDC Cable Considering Interfacial Charge Accumulation

The paper presents a modeling approach for understanding Partial Discharge (PD) in steady state DC voltage in a loaded XLPE insulated DC cable. The study presents the modelling approach of PD patterns due to the presence of an air cavity in XLPE insulation. Interfacial charges present along the XLPE and air cavity walls play a crucial role in determining the PD pattern. The Maxwell-Wagner-Sillars (MWS) theory has been used to determine the interfacial charge present along the cavity wall. Crucial condition for the initiation of PD, the field inside the cavity must be higher than the PD inception field is maintained. The field inversion phenomenon in the DC field and temperature variation across insulation associated with Joule's heating due to conductor current have also been reported. A PD pattern in steady-state DC voltage has been obtained by correlating the interfacial charge accumulation and associated field change in cable insulation.