Investigation of Partial Discharge Phenomena on XLPE Cable Insulation Using COMSOL Multiphysics

The presence of various defects including the presence of micro-cavities, cracks, and contamination of impurities intensifies the field stress inside the insulation when subjected to high voltage (HV), which results in the initiation of discharge activity. Therefore, the measurement and analysis of partial discharge (PD) phenomena are essential for the condition assessment of HV insulation. This study focused on the application of COMSOL multi-physics in an XLPE cable insulation sample with an artificially created cavity defect to evaluate the distribution of electric field stress, PD inception, and extinction phenomena. The COMSOL simulation of the XLPE sample is carried out in the presence of a spherical void by considering the effect of void diameter, void position, and influence of harmonics. The study also replicates the influence of varying harmonic content along with total harmonic distortion (THD) which highlights the importance of PD pattern. It has been observed that PDs tend to concentrate in (dEco(t)/dt), particularly in areas with significant slopes. Whereas, local minima act as inhibitors, and distorted the PD pattern which is 300% and 200% higher in 5th and 7th harmonic as compared to 3rd during 20% THD.