Lightning to earthed structures: Striking distance variation with stroke polarity, structure geometry and altitude based on a theoretical approach

The striking distance and attractive radius of grounded structures to downward lightning strokes depend significantly on the polarity of the stroke. The paper quantifies the reduction of these parameters for positive lightning, together with their lower sensitivity to structure height with the exception of very tall structures. Recent published data on lightning phenomena enables new comparisons of this modelling with field data. Calculations show that the decrease of air pressure, humidity and temperature with increasing altitude results in an increase in striking distance and an increase in the risk of direct lightning strikes for structures in mountain or aviation environments. •Criteria to calculate the striking distance of positive and negative polarity lightning were proposed•Lower sensitivity of striking distance to the mast height for positive polarity lightning was shown•Calculations show the striking distance to increase with altitude