Lightning Protection Strategies for Ground-mounted PV Systems – Publicly Accessible or Enclosed Power Plant

Abstract:
Photovoltaic systems are increasingly becoming an essential part of the electric power supply in Austria to reduce the nationwide greenhouse gas emissions by 36% by 2030 compared to 2005. The large percentage of electricity generation in Austria is already coming from renewable sources, yet the statistics of the total electricity generation of 2020 show that an expansion of wind power and especially the expansion of photovoltaics by 11 TWh is essential. Photovoltaic (PV) systems are subject to electrotechnical regulations, which implies the obligation to consider all norma-tive standards including lightning protection in order to minimize damage to the infrastructure and avoid personal injury and to ensure a reliable energy supply. Ground-mounted PV systems are considered as electrical power generation plants and are erected on designated areas. The present standard in the field of lightning protection is based on the four-part series of the IEC 62305 standard and the relevant national guidelines, which present an overall concept for external and internal lightning protection, grounding and equipotential bonding. The concept of a ground-mounted PV system operated as an enclosed power plant is a com-bination of the IEC 61936-1 standard, originating from the high-voltage field, and the IEC 62305 lightning protection standards. For such cases, in addition to the consideration of the normative lightning protection, organizational measures of the requirements for electrical installations must be applied in an interdisciplinary manner in order to ensure personal safety in the enclosed electrical power plant. Furthermore, an additional installation like an external fence is necessary to prevent access by unauthorized persons. Depending on the situation, fencing and gates must be integrated into the lightning pro-tection concept as well as the grounding system. In specific concepts the arrangement of lightning protection air termination rods might be refrained from. Due to an installed close-meshed grounding and equipotential bonding network, it can be expected that a direct lightning strike will damage plant components only locally. In this case, the operator accepts a possible outage of the affected PV system components. To assess economic losses caused by direct lightning strikes, a damage occurrence assessment shall be car-ried out comparing the estimated system damage per year with the accepted system damage per year in this case.