Box Behnken Design Based-Optimization of 230 kV Grading Ring using Finite Element Method

Abstract

This paper aims to investigate the optimal design of grading rings for high-voltage polymeric composite insulators. A 230 kV composite insulator model geometry with a grading ring was modelled in COMSOL Multiphysics and was used to obtain the electric field distribution on the triple junction near of end fitting of the model by finite element method. Box Behnken Design approach was used to analyse the grading ring effect on the E-field stress. The analysis of variance is used to evaluate the interaction effects of the ring parameters. The relationship between the E-field and the ring parameters is modelled and optimized by the response surface methodology. The optimization results of grading ring lead to a significant reduction of the E-field strength at HV side and to more uniform electric field distributions. The proposed methods can help in improvement of grading ring design in reducing the electric field magnitude on the end fitting of composite insulator.