On the FEM and TL approaches for the calculation of lightning - induced voltages on overhead lines

The paper compares a transmission line (TL) approach with the finite element method (FEM) for the calculation of the lightning-originated surges on overhead power lines due to nearby lightning return strokes. Both the lightning electromagnetic pulse (LEMP) and the induced voltages in an overhead line are calculated by using the developed FEM model. The LEMP waveforms are provided as inputs to the computer code that implements a LEMP-to-transmission line coupling model. The comparison between the induced voltages calculated by using the two different approaches is repeated for the case of an overhead line above a perfectly conducting ground, with and without the shielding effect of building placed along the line, and for the case of lossy ground. The paper identifies and discusses the main causes of discrepancy between the obtained results.