An antenna-theory approach for modeling inclined lightning return stroke channels

In this paper, we investigate lightning return stroke electromagnetic fields and induced voltages on nearby overhead lines associated with an inclined lightning channel. The study is based on the Antenna Theory (AT) model, which is appropriately extended to take into account the channel inclination. This involves modification of the well-known analytical expressions for the electromagnetic field originated by a dipole so that an inclined channel is properly modeled.Using the AT model, the electromagnetic fields are computed at close, medium and far distance ranges, with respect to an inclined lightning channel. It is shown that the channel inclination affects more markedly the fields at close distances. The induced voltages on a nearby overhead line are also investigated and it is shown that channel inclination could result in a significant variation of the induced voltage magnitudes. It is also shown that, depending on the inclination and its relative position to the observation point or to the line, the channel inclination could result either in an increase or in a decrease of the electromagnetic field and induced voltage magnitude.