Behavior of XLPE for HVDC Cables under Thermo-Electrical Stress: Experimental Study and Ageing Kinetics Proposal

The present work deals with the study of the electrical behavior of cross-linked polyethylene (XLPE) used for HVDC cable insulation. The aim is to better understand the influences of electrical and thermal stresses on the insulating material in order to provide useful information for designing HVDC cables. This study was carried out on Rogowski samples made of XLPE insulation with semiconductive electrodes, aged for more than 3 years (1220 days) at three different temperatures (70, 80 and 90 °C) under two DC electric fields (30 and 60 kV/mm). Dielectric loss factor, volume resistivity and space charge accumulation were measured. Results are analyzed and cross-correlated, in order to propose possible ageing kinetics.