TSC and DSC measurements of polymeric insulators used in medium voltage distribution cables

This article describes results of thermally stimulated current (TSC) measurements of XLPE, HDPE and PVC samples, which are used as insulating materials in medium voltage cables used in electrical energy distribution. Systematic investigations have been made in order to correlate physical parameters of charge storage with the breakdown phenomena observed in voltage tracking resistance tests (VTR). Differential scanning calorimetry (DSC) measurements were also performed in order to verify if some of the TSC peaks arise from relaxation processes associated with eventual morphological and/or structural modifications. A correlation is shown between material conductivity and voltage tracking resistance.