Analysis of XLPE Cable Health Assessment Parameters under Various Test Voltages by PDC Method

Cross-linked polyethylene (XLPE) has been widely used as an insulation material in power cables because of its superior electrical characteristics. The measurement of polarization and depolarization current (PDC) is a classical method used to study the health states of XLPE cables. This paper studied the effects of test voltage on the PDC measurement results and assessment parameters calculated results. The PDC tests of one new and one old cable were carried out under 2kV to 6kV with an interval of 1kV. The assessment parameters such as insulation resistance (IR), polarization index (PI), dielectric absorption ratio (DAR), dielectric loss tan δ, and ageing factor were calculated and analyzed. The results show that with the increase of test voltage, all the assessment parameters are almost independent to the test voltage for the new cable. However, for the old cable, the IR, DAR, and PI values decrease, and tan δ increase with test voltage.