Oxidation and thermal resistance of HMW-PE and XLPE HV

The thermal oxidation of the insulation of several unaged and aged transmission and distribution cables has been measured by Fourier transform infrared (FTIR) spectroscopy. It is shown that all cables, even unaged ones, contain traces of oxidation which increases with aging, especially near the conductor shield. The antioxidant content has been investigated by FTIR and ultraviolet spectroscopy and sulfur content measurements. It is shown that the amount of residual antioxidant can be related to the oxidation induction time as measured by differential scanning calorimetry at 200 degrees C in oxygen. The influence of various parameters on cable thermal resistance is discussed.<>