Quantification of Void Effects on High Voltage Power Cable Insulation Degradation

One of the common causes of cross-linked polyethylene (XLPE) insulation aging and eventual cable failure is the presence of voids within the cable insulation. Gas-filled voids can be initiated in XLPE cables during their manufacturing, installation, and operating conditions. Once the size of the void reaches a certain critical limit, noticeable partial discharge (PD) activity develops. Therefore, the size of the void is one of the important factors considered when investigating PD activity in power cables. This paper presents a detailed examination of how different sizes and distributions of voids affect the cable's behavior. A 3D model of XLPE power cable insulation is carried out to improve the understanding of how the electric field distribution responds to different shapes, positions, and sizes of voids within the XLPE insulation. The effect of void size on PD behavior within the XLPE layer of an 18/30 kV cable specimen is studied. Also, the changes in artificial spherical void depths and diameters are investigated.