Calculation of the Lightning Performance of Unshielded Transmission Lines

A computer program to evaluate the lightning performance of unshielded transmission lines has been developed. The program is based on the Monte Carlo and Dynamic Travelling Wave techniques. It is an improvement over previous methods and includes the simulation of a large number of spans with towers of different insulation characteristics, nonlinearities such as corona distortion, lightning arrester operations , dynamic behaviour of earth connections and multiple flashover assessment of transition from impulse flashover to power arc formation. The program has successfully predicted the lightning outage rate and types of several operating unshielded wood pole lines in Australia.