The effect of angular anisotropy in XLPE insulation on dielectric strength

The aim of this study is to characterize XLPE dielectric strength corresponding to the angular anisotropy in extra high voltage (EHV) power cables. The angular anisotropy in EHV power cable is built up in the extrusion process and known as general fluid phenomena. The authors measured tensile strength as the angular anisotropy and then conducted electrical treeing tests using XLPE specimens. With needle-needle electrode system, the measured tree initiation voltage and time in accordance with the angular anisotropy showed distinctive values as the angular direction. From the results, it can be suggested that the angular anisotropy of XLPE insulation material must be considered as the additional factor that affect dielectric strength in EHV power cables