Comparison of Surge Impedance Model and Electromagnetic Field Model of Transmission Tower

Since the tower surge impedance model plays a very important role in the lightning protection calculation of transmission lines, scholars at home and abroad have given a large number of tower surge impedance models, but the differences are very large. In this paper, the electromagnetic field model of a typical tower is established. Through electromagnetic field calculation, the tower surge impedance is obtained and compared with the calculation results of the existing formula. The calculation result shows that when the rise time of the injected current becomes shorter, the refraction and reflection signal are easier to distinguish. Therefore, the impulse impedance of the tower calculated by the electromagnetic field method will tend to the actual surge impedance. The surge impedance calculation result obtained by the formula proposed by Visacro is the closest to the electromagnetic field simulation result, which can truly show the true transient characteristics of the tower.