Modeling of a 500kV Transmission Tower for Lightning Surge Analysis

Abstract

Modeling of transmission towers is an essential part of the traveling analysis of lightning surges in overhead power transmission lines. In this paper, an equivalent distributed constant line model of the transmission tower is developed. The model consists of three parts : main poles, lattices and crossarms. The surge impedance of each part is expressed by the functions of their dimensions and geometries. This tower model is applied to the 500kV transmission tower of which surge performance characteristics are measured. It is found that the tower voltage wave shapes calculated from this model closely agree with the measured ones. This proves that the authors' proposed tower model well simulates the surge performances of an actual transmission tower.