Sample insulator sector
It is both a tedious task and unnecessary to micro-analyze the leakage current distribution along the entire insulator. Instead, a sample sector of the insulator was selected, where the boundary conditions (local potential and electric field) resulting from those conditions were placed around that sector. The insulator sector has two sheds; one shed is long and the other is short with a total creepage distance of 186.14 mm. The leakage current density materialized on the insulator surface as then sought by means of ANSYS. Unigraphics was used to simulate this sample insulator sector as shown in Fig 1c. The directional components x and y of leakage current density were obtained, from which the tangential (surface) current subsequently resulted.