Touch voltages in ground mounted PV power plants caused by earth faults or lightning strikes

In this work we calculate the touch and step voltages in large ground mounted PV power plants either caused by earth faults in nearby high voltage power systems e.g. towers, substations or direct lightning strikes, respectively. Rammed steel profiles are often used instead of conventional concrete foundations to enable large ground mounted PV systems to be installed easily and quickly. These driven steel profiles act like natural earth electrodes and can therefore contribute to the earthing system. The aim of this work is to find out whether these natural earth electrodes together with equipotential bonding are already sufficient to ensure personal safety. Therefore we analyse the touch voltages of two main scenarios: First the interference in low frequency range for high voltage faults in nearby substations or line towers and secondly a lightning strike within a ground mounted PV power plant. Both scenarios have certain limits according to current standards.