Insulation Aging Evaluation Method of High Voltage Cable Based on Dielectric Loss Characteristics

Health assessments of high-voltage power cables are important for stable operations of power grids; however, most current health assessment model parameters lack whole cable test data, making them unable to effectively characterize the insulation aging state of whole cables. In this paper, a dielectric loss measurement device for high-voltage cables is developed. Using a high-voltage amplifier and high-precision dielectric loss measurement algorithm, the dielectric loss values of whole cables at different aging stages are measured, and the physicochemical and electrical characteristics of XLPE slice samples at each aging stage are analyzed. Through the analysis of high-voltage dielectric loss, crystallinity, carbonyl index, AC breakdown field strength, and elongation at break, aging correlation parameters are determined. The characteristic high voltage frequency domain dielectric response and delamination degree are proposed to characterize the aging state of cable insulation. The correlation between the high voltage frequency domain dielectric characteristics and cable insulation aging state is established. Finally, an assessment method of the insulation aging state of high-voltage cable is developed, providing a reference for the diagnosis and assessment of the insulation state of high-voltage XLPE cable on site.