Investigating Lightning Induced Currents in Photovoltaic Modules

Bypass diode failures have been observed within solar photovoltaic (PV) plants after thunderstorm activity, with no evidence of direct lightning strikes to the PV plant. This paper examines the mechanisms by which currents may be induced within PV installations. Firstly by means of computational electromagnetic simulations, and secondly by means of real-world testing in a high-voltage laboratory. These investigations were conducted with the objective of minimizing the magnitudes of induced currents within a PV installation. It was found that poor inter-module wiring in a PV installation, and not the internal layout of the PV modules themselves, resulted in the largest magnitudes of the induced currents, and that better wiring practice would significantly reduce these magnitudes. The presence of the conductive frame of a PV module was shown to reduce the magnitudes of the currents induced within the installation.