The evaluation of LEMP effects on subtransmission line using the method of moment: a comparison between TL and MTL model

An attempt has been made to evaluate the induced voltage on a 63 kV subtransmission line caused by lightning electromagnetic pulse (LEMP). For this purpose the electric field integral equation (EFIE) in time domain has been solved by the method of moment (MOM). The lightning channel is modelled by a monopole antenna, and according to the method of moment the excitation generator of proposed antenna is selected in such a way that time-space current distribution along the channel is compatible with the transmission line (TL), or modified transmission line (MTL) models. For both models the induced voltage along any point of the 63 kV phase conductor can be evaluated. The effect of shielding the wires can also be analysed. It is assumed that the lightning return stroke originates from the Earth surface in vicinity of the 63 kV structure. The proposed accurate method will help engineers to have an outstanding view on the protection of a 63 kV subtransmission line against lightning