Partial discharges impact on the electrical properties of low-density polyethylene power cable insulation

Abstract In this work, the effects of electrical aging on the structural and electrical properties of low-density polyethylene (LDPE) used as cable insulation are examined. Fourier-transform infrared spectroscopy spectroscopy revealed oxidative degradation characterized by the progressive formation of carbonyl groups, while scanning electron microscopy observations confirmed surface morphological changes induced by oxidation. LDPE films were subjected to intense partial discharges under an AC electrical field for 10 and 20 h, and their electrical performance was systematically evaluated. Measurements of DC resistivity, charging and discharging currents, polarization, and leakage currents demonstrated clear degradation of LDPE insulating properties with aging time. The decrease in surface and volume resistivity, the increase in charging and discharging currents, and the unexpected reduction in leakage current were directly correlated with structural and chemical modifications. Overall, the combined structural, morphological, and electrical analyses consistently show that electrical stress accelerates the structural deterioration of LDPE, providing reliable indicators of insulation performance loss.