Optimal Design of Corona Ring for 132 kV Insulator at High Voltage Transmission Lines Based on Optimisation Techniques

Abstract

The installation of a corona ring on an insulator string on a transmission line is one of the solutions to reduce the electric field stress surrounding the energised end of the insulator string. However, installing a corona ring with an optimum design to reduce the electric field magnitude on an insulator string is a challenging task. Therefore, in this work, a method to achieve the optimum design of a corona ring for 132 kV composite non-ceramic insulator string was proposed using two optimisation methods: the Imperialist Competitive Algorithm (ICA) and Grey Wolf Optimisation (GWO). A composite non-ceramic insulator string geometry with and without a corona ring was modelled in finite element analysis and used to obtain the electric field distribution in the model geometry. The electric field distribution was evaluated using a variation in the corona ring's dimensions, i.e., the ring diameter, the ring tube diameter and the vertical position of the ring along the insulator string. From the results achieved, a comparison of the minimum electric field magnitude along the insulator string with a corona ring design shows that the minimum electric field magnitude is found to be lower using optimisation techniques compared to without using optimisation techniques by between 3.724% and 3.827%. Hence, this indicates the capability and effectiveness of the proposed methods in achieving the optimum design of a corona ring on an insulator string.

Case Study: Optimizing Grading Ring Design for High Voltage Polymeric Insulators in Power Transmission Systems for Enhanced Electric Field and Voltage Distribution by Using a Finite Element Method

“…The consistency between our findings and those presented in [28,29] and by Aramugam [33,34] further validates the reliability of our simulation. These studies collectively support the effectiveness of grading rings in improving the performance of polymeric insulators.…”

“…Unlike other methods that only identify one or two optimum values under specific conditions, this approach provides multiple options for factories to determine the most suitable cost and electric field (E-field) from a wide range of values. It is worth noting that all the obtained values fell within the recommended range for the E-field indicated by the EPRI (4.2 kV/cm) and taken into account in similar research studies (see, e.g., [28][29][30][31][32]) and by the IEEE (4.5 kV/cm) [30,33]. This comprehensive analysis will enable factories to make informed decisions based on their specific requirements and constraints, considering both cost optimization and adherence to recommended E-field ranges.…”

“…Furthermore, for a more comprehensive comparison of our results, we considered the study conducted by Aramugam et al [33], where they utilized COMSOL Multi-physics software version 4.3 along with a grey wolf optimization (GWO) and an imperialist competitive algorithm (ICA) implemented in MATLAB software for a 132 kV composite insulator. In their investigation, the electric field was individually calculated for varying values of R, r, and H, while maintaining the other parameters constant.…”

“…In their investigation, the electric field was individually calculated for varying values of R, r, and H, while maintaining the other parameters constant. Notably, they discovered the optimal dimensions for the corona ring to be R = 82.181 mm, r = 24.897 mm, and H = 20.978 mm, resulting in the lowest simulated electric field of 3.724 kV/cm [33].…”

“…The dimensions obtained for the grading ring design, as reported in [29,[33][34][35][36], can be considered as optimized values. It is important to note that these values represent custom cases and should be regarded as recommendations in view of the lack of a general method or universal standard.…”