Lightning-induced voltage on overhead lines

Abstract

The report is devoted to creating a model for calculation of lightning-induced voltages on overhead lines during indirect lightning return strikes starting from the channel-base current. The calculation of lightning-induced voltages is generally performed in the following way: 1) electromagnetic field is calculated across the length of the line, using the model of the lightning return-stroke current as a function of time and the height of the channel. The channel of the lightning current is taken as a straight vertical antenna; 2) the electromagnetic field is then used to calculate the induced voltages using of a coupling model, which describes the interaction between the field and the line conductors. This model is based on the transmission line theory; 3) the shape and amplitude of the waves on the line at an arbitrary distance from the lightning stroke is based on the calculated induced voltage. The procedure is applied for the analysis of the voltages induced on overhead line by indirect lightning strikes with an equidistant point from the ends of the line. The influence of some parameters such as lightning discharge, striking point and terminating impedance of load currents on the induced voltage amplitude and waveshape is examined.