HVDC Extruded Cables-Parameters For Determination of Stress

The distribution of electric stress in the insulation of a h.v.d.c. cable is determined by the resistivity of the insulation, which is dependent both on temperature and stress. In the present work an attempt is made to quantify for polymeric insulation the parameters of an equation for resistivity of the form used for paper/oil, i.e. ρ= ρexp-(αθ+ ßE). Tests have been performed on flat sheet and gas- impregnated tape HDPE insulations and on extruded XLPE cables manufactured with both steam and dry curing processes.