Optimisation of corona ring design for composite insulator strings

Purpose - The purpose of this paper is to propose an optimum design of a corona ring for insulator strings using optimisation techniques, which are gravitational search algorithm (GSA) and imperialist competitive algorithm (ICA). Design/methodology/approach - An insulator string model geometry with a corona ring was modelled in a finite element analysis software, and it was used to obtain the electric field distribution in the model. The design was optimised using GSA and ICA. The variables were the corona ring diameter, ring tube diameter and vertical position of the ring along the insulator string. Findings - Using optimisation method, the minimum electric field magnitude on the insulator string with a corona ring design is lower than without using optimisation method. GSA yields better results than ICA in terms of the optimised corona ring design. Practical implications - The proposed methods can help in improvement of corona ring design in reducing the electric field magnitude on the energised end of insulator strings. Originality/value - A new method to design an optimum corona ring for insulator strings, which is using optimisation methods, has been developed in this work.