Tracking resistance and breakdown strength evaluation of eco-friendly insulation materials for overhead line

XLPE is the commonly used insulator for overhead cables. Recently, research has been underway to develop alternative materials to replace XLPE due to issues such as cross-linking byproducts and difficulties in recycling. PP is being extensively researched as an alternative insulation material to XLPE. It is a thermoplastic polymer material that does not undergo a crosslinking process. For PP to be used as an insulator in power cables, it must exhibit insulation properties equivalent to or better than those of XLPE. This paper conducted AC breakdown strength tests on two types of XLPE, which are commonly used as insulation materials for overhead cables in Korea, and five types of PP with different blending ratios of filler and elastomer, and quantitatively compared the results using Weibull distribution analysis. To evaluate the stability of cables in outdoor environments, tracking resistance tests were conducted with reference to the IEC 60112 standard. Tracking resistance tests are typically evaluated on a pass/fail basis, making relative comparisons between materials with the same rating challenging. To address this limitation, this paper analyzed image data obtained during the tracking tests by converting it into fractal dimensions, enabling a detailed evaluation of the tracking resistance properties of each insulation material.