Lightning protection design of solar photovoltaic systems: Methodology and guidelines

Solar photovoltaic (PV) system is one of the promising renewable energy options for substituting the conventional energy. PV systems are subject to lightning damage as they are often installed in unsheltered areas, and have vulnerable electronic devices. This paper proposes a partial element equivalent circuit (PEEC) method enhanced with the vector fitting technique for analyzing lightning transients in the PV systems. The frequency-dependent effects and ferromagnetic properties of structural steel are taken into account. Models of major components in the PV systems including structure steels, wiring in panels, and PV cells are provided. The non-linear surge protective device (SPD) is also considered in the modelling. An experiment on a PV panel is presented for the validation of the proposed method. The proposed procedure is finally applied to investigate lightning transients in a practical PV system. The lightning failure mode of bypass diodes is identified for the first time. The results can help to design effective lightning protection and select appropriate parameters of protective devices.