Large ground-mounted PV plants face significant lightning-induced transient voltages that can increase step-voltage hazards, especially in open, high-exposure terrains, requiring carefully designed earthing and bonding systems. Researchers from Austria used frequency-resolved electromagnetic simulations to show that equipotential bonding reduces risks, but effectiveness depends strongly on soil resistivity and is not guaranteed by standard grounding resistance limits alone.
Large ground-mounted solar plants cover wider areas, use extensive metal structures, and are often built in open, high-exposure terrains. This combination increases the likelihood that lightning strikes or nearby strikes will induce larger transient voltages across the site, making step-voltage risks more significant unless the earthing design is carefully engineered.
With this in mind, a group of researchers from the Graz University of Technology in Austria has investigated the transient behavior of ground-mounted photovoltaic installations under lightning conditions using detailed case studies. By calculating surface potentials and step voltages, they evaluated how different earthing and equipotential bonding strategies perform in maintaining safety limits defined by IEC standards.
