Understanding of Outdoor Insulator Characteristics through Leakage Current and Electrical Equivalent Circuit

Outdoor insulator is one of the important equipment in an electrical power system. The failure of the isolator, especially in the form of flashover, contributes significantly to the total system failure. In order to improve the performance of the outdoor insulator, a number of efforts have been made, such as the use of new materials, surface coatings to improve dielectric strength and improvement of insulator design. Systematic efforts to improve insulator performance require an understanding of insulator behavior. This paper describes how to understand the behavior of an insulator by using an electrical equivalent circuit derived from the leakage current waveform. Using the proposed equivalent circuit, the leakage current wave simulation was carried out for ceramic and silicone rubber insulators under clean fog and salt fog conditions. Information about insulator parameters such as resistant, non-linearity property and arc that can be obtained from simulation are important to improve the performances of the insulators