59 / 2022-03-08 20:04:49

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

Polarization and depolarization currents,XLPE cable,Test voltages,Insulation resistance,Dielectric loss

XLPE has been widely used as an insulation material in power cables due to its excellent electrical, mechanical, and chemical properties. It is beneficial having a holistic diagnostic technique to assess XLPE cable insulation state of health to pre-empt any failure in service. The measurement of polarization and depolarization current (PDC) is a classical measurement method used to study the properties of insulation materials. By analyzing the PDC test results, the information about polarization and conduction, such as dielectric loss tanδ, polarization index (PI), dielectric absorption ratio (DAR), aging factor, insulation resistance (IR) can be obtained. Some guidelines of those parameters have been studied to diagnose the aging state of XLPE insulation. However, the effects of test voltages on the calculated parameters results of XLPE cable insulation are seldom reported. Studying the effects of test voltages on parameter acquisition results can provide guidance more accurately for cable insulation state diagnosis.

In this work, the 6.6kV copper conductor XLPE insulated cables with thickness of 3.4mm are taken as the tested objects. The test equipment is Megger S1-1568, which is a commonly used in field test in engineering. The tested voltage is from 2kV to 7kV with interval of 1kV, and both the polarization and depolarization time is 1000s. According to the PDC test results, the IR, PI, DAR, aging factor, dielectric loss tanδ, polarization loss, and conduction loss are calculated to analyze the effects of test voltages on those parameters.


The results show that the polarization currents increase nonlinearly with test voltages, while the depolarization currents increase linearly. The insulation resistance, DAR and IR values decrease with test voltages, and the conduction loss increase with test voltages. Details will be provided in the full paper.


The test voltage is a crucial factor influencing the IR and other calculated assessment parameters results. In the future, it should be confirmed that the test voltage of each on-site measurement should be the same. Otherwise, it could be challenging to obtain a unified guideline.