Comparison between the use of surface and volume conductivity to compute potential distribution along an insulator in presence of a thin conductive layer

This paper describes a comparative study on the modeling of a thin conductive dielectric layer usually found on polluted or ice-covered insulators. Two different approaches such as those offered by most FEM commercial software were studied. The first one is a volume approach which takes into account the thickness of the thin layer. The second is the surface approach where the thin layer is treated as a specific boundary condition. Simulations were performed using the FEM commercial software Comsol Multiphysics^® that allows both volume and surface approaches. Parameters such as conductivity and permittivity of the thin layer as well as the number of elements used are studied both in 2D axisymmetric and 3D modeling. The results obtained demonstrated that the surface approach is the best solution as it provides the same results as the volume approach but with 3 times less elements required for the mesh. The surface approach should then be considered for 3D complex problems where thin conductive dielectric layer is present.