Field measurements of lightning-induced voltage transients in PV arrays

It is known that nearby lightning strikes can induce overvoltages in photovoltaic arrays. However, although many laboratory studies have been reported, relatively few field studies have appeared in the literature. This paper reports on a field study conducted at South Dakota State University and the Florida Solar Energy Center in which a high-speed datalogger was used to monitor the voltage at the terminals of two photovoltaic arrays. The design of the datalogger is described, and its measurements are given and discussed. Two important conclusions were reached: one, that the field measurements seem consistent with laboratory measurements and suggest that DC-side protection for PV power electronics is important; and two, that it is not always possible to tell from anecdotal observations whether a lightning storm is dangerous for PV power electronics.