Currents in buried grounding strips connected to communication tower legs during lightning strikes

During a lightning strike to communication tower stroke currents are shared by the tower and by the shields of the cables along the tower. The currents in the tower proceed towards the grounding system (possibly a combination of counterpoises or ring conductors or ground rods or grounding grids) connected to tower legs' foundation. In this paper, lightning strike to communication tower on mount Gaisberg in Austria is considered and measured currents at the tower top and those shared by an instrumented grounding strip connected to one of the tower leg's are presented. The measured currents at different locations on the 70-m long ground strip are compared with the predictions of a frequency dependant lossy transmission line (TL) model and reasonably good agreement was found. From this validation it is claimed that the TL models are appropriate for lightning transient analysis of grounding systems.