Local surface field- and charge distributions and their impact on breakdown voltage for HVDC cable insulation

Abstract. The surface topography on material interfaces plays a crucial role in performance of HVDC cable systems. In this work, the texture of interfaces was analyzed and its impact on electric field distributions at the surface was simulated. It was found that the effect of roughness and field dependent bulk conductivity of the insulation on the field distribution is associated with significant local quantities of space charges accumulated at the surface. It is shown that charge accumulation and corresponding local electric field enhancements are the parameters defining local conduction, injection and material degradation at insulation interfaces. A correlation between simulated/calculated field distributions and ramped DC breakdown voltages on cable peelings was observed