Comparison of polymeric insulation materials on failure development in low-voltage underground power cables

Sustainable developments impose increasing pressure on Low Voltage (LV) underground power cables, leading to an increasing interest in condition assessment for LV systems. LV cables have been designed mainly on mechanical considerations taking insulation of low voltage levels for granted. However, concerns on degradation aspects is now growing. To make a comparison of insulation materials, water cycling tests on artificially damaged cable sections have been performed. The results show that the material has a major role in degradation rate due to local decomposition upon dry-band arcing, as can also be expected from chemical point of view. Chemical compounds add pollution to the damaged spot, enhancing degradation. PVC shows fastest degradation rate compared to polyurethane and XLPE respectively. These results can be considered in optimal cable design. In addition, aspects like water tightness should also be considered.