Studies on Electric Field Distribution and Partial Discharges of XLPE Cable at DC Voltage

Partial discharge (PD) detection is considered as a reliable method to analyze the operating status of the electrical equipment. But there are only a few literatures about PDs of cross-linked polyethylene (XLPE) cable at DC voltage. So this paper mainly concentrates on electric field distribution and PD phenomena of DC XLPE cable. Numerical simulation method is applied to analyze electric field distribution in normal and four typical insulation defect (corona defect, cavity defect, scratch defect and creepage defect) models. Electro-thermal coupling model is established to solve this problem. The simulation result shows that four defects can cause different electric field distortion. Among them, corona defect has the most serious distortion and creepage defect has the most slightly distortion. The high voltage test is applied to verify the simulation result. The H(q, Delta t) spectrums of PD signals confirm that serious electric field distortion can cause severe PD phenomena.