VOLTAGE DISTRIBUTION ACROSS STRING INSUL

Insulators for overhead lines are considered to be of basic importance to the transmission system, through their ability to insulate the power lines as well as their function in carrying the weight of the line conductor. For higher voltages, a string of suspension insulators is used where the number of insulator units depends on the voltages of the lines. This paper calculates the voltage distribution by sphere gap methods and compares the results, while also attempting to make the voltage distribution across the insulators uniform using guard rings. Theoretical calculations of voltage distribution across the string insulators are compared with practical values. The results demonstrate that the voltage distribution is nonlinear, decreasing as one moves from the line end and slightly rising at ground level, thereby indicating that the sphere gap method is effective. The voltage distribution for 4 disc insulators can be approximately made uniform by connecting a guard ring at the line end. This highlights that the line end insulator shares a higher percentage of voltage, potentially leading to Radio Interference Voltage.