Relief of an Electric Field via a Cone Structure

A terminated power cable is typically applied not only for terminated ends but also to connect two or more cables. The electric field inside the insulation layer becomes disturbed when a coaxial cable structure is broken and the electric stress increases near the ground edge. A structure of cone type is a major method to alter the lines of equi- potential and to relieve the electric stress around the ground. The dimensions of the cone depend on the cable structure. In this paper we introduce a way to calculate the displacement of equi-potential lines when a cone is brought into a coaxial cable, RG220, and then determine a suitable angle and length of the cone, which are important factors to withstand tens of kV and even greater. The corresponding high-voltage tests are also presented here.