Effects of the PV-generator's terminals connection to ground on electromagnetic transients caused by lightning in utility scale PV-plants

The connection to ground of the negative or positive terminal of photovoltaic (PV) generators is a common practice to mitigate the effects of the potential induced degradation (PID), which is attributed to chemical reactions (ion's exchange) between the materials that constitute the PV-module during operation. Furthermore, the complex topology of a utility scale PV-plant, its dimensions and the stored energy in the central PV-inverter's DC-link open the hypothesis that overvoltages at the DC- and AC-side of the PV-plant may arise during transients caused by impulse currents. The objective of this publication is to explore the effects of this practice on the operation of utility scale MW-class PV-plants during transients caused by lightning.