Investigation on Various Factors Affecting Dielectric Strength of Disc Insulator

Cheong, Zhen Wai (2024) Investigation on Various Factors Affecting Dielectric Strength of Disc Insulator. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

This research investigates factors affecting the dielectric strength of porcelain, glass and silicone rubber disc insulators used in high-voltage transmission lines by analysing the maximum electric field strength (Emax) that they experience. Through finite element simulations using ANSYS Electronic Desktop Student, it finds that the voids closer to the conductor, the larger void the sizes, voids with higher permittivity and the surroundings with higher permittivity all lead to significantly higher Emax which will increase the risk of insulator breakdown. The study highlights the importance of optimal insulator design and maintenance to prevent water ingress that can compromise dielectric performance. It provides insights to improve design, and maintenance strategies and develop new insulation materials with enhanced dielectric properties and breakdown resistance. When the position of the void is changed within the same insulator, silicone rubber exhibits better resistance to electrical stress compared to porcelain and glass. This allows it to better distribute and withstand electric field stresses, resulting in a more uniform Emax across different void positions within the disc insulator. When the position of the void is varied across the different insulators, porcelain and glass generally showed higher Emax values compared to silicone rubber, making them more susceptible to breakdown under the same conditions. Moreover, silicone rubber is less sensitive to changes in void size compared to porcelain and glass. Furthermore, materials with higher relative permittivity (water) lead to higher Emax values across the three different insulating materials, indicating a higher susceptibility to breakdown. Recommendations include investigating the combined effects of multiple factors, experimental validations and continued material advancements to ultimately ensure reliable and efficient operation of high-voltage transmission systems.