Optimal design of high voltage composite insulators with grading rings in different configurations

Abstract

Reliability of high voltage composite insulators depends on achieving an optimal electrical and geometrical design that produces the lowest electric field strength. This paper proposes a method to find the optimal geometrical design of composite insulators for different voltage levels. The design variables of the insulators include dimensions and locations of sheds and grading rings, as well as physical properties of the insulators. One composite insulator with single grading ring and two with double grading rings are considered and optimized. Considering the complexity of modifying composite insulator parameters to find the lowest electric field strength, five different optimization algorithms are applied and compared to find the optimal geometric design. The main objective of these optimization algorithms to be minimized is the maximum electric field strength, which is calculated using the finite element method-based COMSOL Multiphysics. The results for three different composite insulators under study show that the particle swarm optimization (PSO) algorithm produces the best results in terms of optimal geometrical design to minimize the electric field strength. In addition, the optimal design can reduce not only the electric field strength in clean, uniform pollution and water droplets environmental conditions but also the creepage distance of composite insulators. These improvements in optimized models are achieved without introducing any additional consideration besides the optimal dimensions.