Conductivity of crosslinked polyethylene influenced by water

The conductivity of XLPE insulation plates has been measured with different levels of water concentration. Tapes have been used to humidify the insulation plates in a heat treatment step. Three different levels of water concentration was provided by the tapes. The apparent conductivity was measured for 24 h at 70°C and 30 kV/mm. It is found that the conductivity is increasing with increasing water concentration. It is also found that other polar substances emanating from one of the tapes had a dominating influence on the conductivity. In combination with high water concentration, the conductivity is increased to more than 100 times the conductivity of the reference plate.