Insulation Performance Analysis of Field Aged and New MV XLPE Cables Using Various Diagnostic Techniques

Cross-linked polyethylene (XLPE) cables are widely used in the distribution and transmission networks of power systems. The insulation materials of these cables are stressed by the over voltages and are also exposed to various environmental conditions. This leads the power cables to degrade during their normal life span. Therefore, it would be advantageous for the power utilities to acquire the cable’s insulation condition frequently during their operation. In this paper, experimental studies were carried out on short sections of field aged as well as un-aged medium voltage (MV) XLPE cables to investigate the insulation condition using non-destructive diagnostic techniques such as Dissipation Factor (DF), Isothermal Relaxation Current (IRC), and Partial Discharge (PD) characteristics at 60Hz. From this set of experiments, different parameters will be used to analyze the dielectric response and the insulation condition. Finally, the results show how the VLF dissipation factor works efficiently to assess cable aging.