An experimental approach of the transient effects of lightning currents on the overvoltage protection system in MW-class photovoltaic plants

The aim of this paper is to explore and disclose the experiences during the measurements of the effects of lightning transient currents injected by means of a surge generator on the DC overvoltage protection system on a real MW-Class photovoltaic (PV) plant. The main motivation of this work is to explore the effects of the transient voltages and currents under real operation conditions in form of travelling waves within the PV plant, which may be characterized in its transient behavior during the interaction of its components, such as, PV-modules, mounting (racking) system, PV inverters and grounding (earthing) systems. Further, simulation models were developed with the computational program EMTP-ATP in order to explore transient effects within the PV-plant with main focus on the overvoltage protection (OVP) system on the DC side of the electrical installation, taking the measurements of the real PV-plant as a reference for the validation of the models. Finally, a recommendation a strategy for commissioning and/or energizing the PV-plant with central PV-inverters is disclosed.