Modeling and Analysis of PyroCb Lightning Leader Impacts on PV Systems

Pyrocumulonimbus (pyroCb) thunderstorms from intense bushfires are major lightning sources, igniting secondary fires and damaging electrical infrastructure. Unlike conventional lightning surge studies based on generic thunderstorm conditions, this study develops a novel modeling framework rooted in atmospheric pyroCb thundercloud dynamics. A numerical model is employed to simulate downward leader propagation in pyroCb lightning via the dielectric breakdown model, explicitly coupling charge structure, wind-shear-driven displacement, and leader dynamics with surge analysis. Results show wind shear extensions of 0–12 km significantly influence charge distribution and lightning type, shifting from intracloud to negative cloud-to-ground (–CG) discharges as initiation potential changes from 49.34 MV (4 km extension) to –450.69 MV (12 km extension). Findings indicate that CG flashes predominantly strike within 26–27 km, emphasizing charge density variations in leader development. The extracted return stroke current, peaking at 350 kA, is modeled as a MATLAB time-series function and applied to a grid-connected photovoltaic (PV) system to analyze surge effects. Results show pyroCb lightning surges propagate through electrical networks, causing extreme overvoltages, equipment failure, and operational disruptions. By directly linking pyroCb atmospheric processes with renewable energy infrastructure response, this study makes the first integrated assessment of bushfire-driven lightning surges on PV systems. These findings emphasize the need to assess renewable energy infrastructure vulnerabilities to extreme weather-driven lightning events. By clarifying leader dynamics and surge impacts, this study advances lightning protection research and highlights the importance of robust mitigation strategies to safeguard electrical systems against pyroCb lightning hazards.