66 kV Overhead Transmission Lines Performance Evaluation toward Lightning Strike with Modeling and Simulation

摘要

A higher probability of shielding failure or back flashover at the tower has been found in transmission lines operating under the tropical conditions due to a high lightning flash density. This failure would make outages on the overhead transmission line. Therefore, mitigation is necessary. This paper provided models and simulation on 66 kV overhead transmission lines, evaluate its performance with the consideration of two scenarios to improve shielding protection, i.e., by additional ground wire and by elevating the cone top of the tower. According to the simulation result, the increase of the cone top of the tower is not only slightly reduce the protection angle, but also increase the value of tower surge impedance. Therefore, the mitigation by elevating the cone top of the tower isn’t more effective than adding the number of earth wire which significantly reduce the protection angle without increase the tower surge impedance, resulting in the decrease of insulator overvoltage.