A finite-element-based reverse identification of DC conductivity based on leakage current measurements on miniature cables

DC leakage current measurements on miniature cables are presented. Two approaches are proposed to deduce the DC electrical conductivity of the tested insulation material from these measurements: one approach based on an assumed electric field value in the insulation, and a coupled LMA-FEM approach which does not require this assumption. It is shown that using a-priori electric field values leads to significant mistakes on the identified DC conductivities, which can lead to underestimated DC conductivities.