High Voltage Insulation Assessment Based on a Mathematical Model of Transmission Line with Lightning Strike Simulation

Abstract

Lightning is a natural source that causes a major failure on power system especially in transmission line. It could decrease the reliability of the power system due to generating the overvoltage phenomenon which lead to insulator broken. When lightning strokes the tower or the ground wire, the effect of different lightning will have different consequences for voltage rise and affect to discharge process. During the discharge process, the voltage in each arm of tower will rise and lead to insulator being broken due to insulator being unable to withstand the current surge. Hence, the number of footing resistance took a crucial part during this process. Higher footing resistance will hinder the discharge process and affect the magnitude of voltage raises throughout the transmission lines. In PT. Vale Indonesia, the magnitude of footing resistance is varied and no standardized value to maintain the footing resistance value. The standardization of footing resistance is required to prevent large-scale failure from occurring in the system. This paper aimed to obtain the effect of direct strike in transmission tower and the optimum value of footing resistance to prevent large scale of failure that affect to production for PT. Vale Indonesia transmission line system considered by simulation from ATPDraw.