Lightning-induced voltage on overhead conductors in urban areas: A study on how the air gap between buildings affects the shielding effect

Lightning-induced voltages significantly contribute to flashovers in medium-voltage (MV) overhead distribution lines. These voltages, generated by the electromagnetic fields of nearby lightning strikes, pose a substantial risk to system reliability and operational safety. The magnitude of these induced voltages strongly depends on the surrounding environment, particularly on the presence and characteristics of nearby objects. Nearby objects can influence the voltage waveform across pole insulators, either by altering its shape or attenuating its intensity. This study investigates the specific impact of the presence of air gaps between adjacent buildings on the induced voltage along MV lines placed in urban areas. By comparing scenarios involving separated buildings to those where a single continuous structure is considered, the research highlights how the structural configuration affects the line's susceptibility to electromagnetic fields. To evaluate the impact, simulations are conducted using a Finite-Difference Time-Domain (FDTD) method-based solver. This computational approach enables detailed analysis of both the spatial variations in electric field strength and the temporal evolution of the induced voltage along the line. The results provide insights into the electromagnetic interactions between the distribution lines and their surrounding structures, offering valuable information for optimizing the design and layout of MV distribution systems to mitigate lightning-induced hazards.