Improvement of Mechanical and Electrical Strength of the Cap-and-Pin Type String Insulators

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Functionality and reliability of electric power transmission systems highly depend on insulators that isolate conductors from each other, the towers, and the ground. The insulators undertake high electrical mechanical stresses for long periods of time. The insulators must maintain their physical properties and mechanical strength over long periods without deterioration. The good performance of insulators results from using proper materials, suitable design, and modern manufacturing technology. The mechanical and electrical characteristics of an insulator are affected by the static mechanical loads (suspension or tension), dynamic mechanical loads (short circuit, wind, and conductor galloping), temperature, and high electric field. The mechanical loads, temperature, and high electric field can degrade the insulators' performance, which will compromise the quality and reliability of the electric power delivered by the transmission line system.Ideally, transmission line insulators should be inspected regularly to ensure maximum service reliability. However, due to the large number of insulators in service (e.g. over 150M porcelain insulators in North America), this is not practical for utility companies. Improvement of insulator design to make them durable for longer life of service has been a topic of interest for many years. The withstand voltage of insulators will be improved by increasing the mechanical, thermal, and electrical strength. The purpose of the proposed research project is to introduce a new method to design high voltage insulator based on finite element method (FEM) and standardized methodologies of electrical and mechanical tests in partnership with Powertech High Voltage Laboratory. The outcome of this research will provide an optimized design for insulators that will improve both their mechanical and electrical withstand. The improved design will enhance the competence and presence of Powertech Labs in high voltage insulator manufacturing industry.