Design and Electric Field Analysis of 33kv and 66kV Polymer Insulators for Different Geometrical Configurations by Finite Element Method

Polymer insulators are widely used in transmission and distribution systems to provide reliable electrical insulation and mechanical support. Gradual deterioration of these insulators leads to frequent flashovers, causing negative consequences for the power system. These adverse effects are attributed to the presence of high electric stresses and surface contamination on the insulators, which cannot be directly observed. Estimation of these stresses can be done numerically by different procedures, which is a tedious and lengthy process. The change in the geometric configuration of the insulator's extreme shed (at the HV terminal) can reduce the electric stresses. In this paper, 33kV and 66kV Polymer insulators are designed with and without extreme large diameter shed in the FEMM-2D software and the electric field distribution is analyzed at different critical points. Stresses are reduced when insulators are designed with extreme shed (At the HV side shed) with a large diameter as compared to a small diameter. With the incorporation of the larger shed, notable reductions in electrical stresses are observed at critical points. For example, under a 21kV application, electrical stresses decrease by 10% within the FRP, 1.5% on the first shed, and remain unchanged inside the SiR and over more than 10mm of the SiR insulator surface. Similarly, at 75kV, there is a 6% reduction within the FRP, 1.5% on the first shed and in the creepage distance, with no change inside the SiR and over more than 10mm of the SiR insulator surface.