Thermo-electric field distribution around a defect in polyethylene [power cable insulation]

In the presence of a stress enhancement, a lightning surge causes space charge formation and power dissipation which can result in substantial temperature rise in power cable dielectric materials. Poisson's equation and the thermal diffusion equation have been solved in 2D with field-dependent material parameters to compute temperature rises of nearly 60 K during a 10 ns risetime surge which produces a background field of 40 kV/mm applied to a 300 /spl mu/m protrusion with a 2.5 /spl mu/m tip radius.