Protection Against Direct Atmospheric Discharges and Overvoltages in Photovoltaic Installations

The increasing global energy demand has led to the expansion of photovoltaic (PV) power plants, particularly in response to climate goals like the European Union's “Fit for 55” initiative to reduce CO2 emissions by 55% by 2030. However, as PV installations grow, their vulnerability to atmospheric discharges, such as lightning, also increases. This study investigates the design and dimensioning of lightning protection systems for PV plants, focusing on two methods: traditional protection per IEC 62305 standards and ionizing devices based on NP 4426 standards. Both methods were analyzed for technical feasibility and cost-effectiveness. A case study of the PV installations at the Lisbon Engineering School (ISEL) was conducted, and a risk analysis determined that Level III protection was required. The study demonstrated that both methods provide effective protection, but ionizing devices offer a more cost-efficient solution, with lower material and labor costs. Consequently, the study showed that ionizing method is around 35% affordable than traditional rods for protecting PV plants in urban environment against atmospheric discharges.