Photovoltaic power plants are commonly built in open

unshielded areas

making them highly vulnerable to lightning strikes. The bypass diode

which plays a crucial role in protecting photovoltaic cells

has low insulation levels and is susceptible to damage from lightning surges

leading to interruptions in power generation. To better understand the lightning-induced damage mechanism of bypass diodes

this study proposes a modeling approach for electromagnetic transients in photovoltaic systems. The method includes transient models for photovoltaic modules and mounting conductors

which were experimentally validated in the laboratory. Based on this approach

numerical simulations were conducted to examine the transient response and damage mechanisms of bypass diodes under real-world lightning conditions. The results indicate that the transient voltage across the bypass diodes is primarily determined by the transient magnetic field generated by the lightning current. During lightning strikes on photovoltaic arrays

the average transient voltage across the bypass diodes can exceed 400 V

leading to large-scale breakdowns. The installation of lightning rods reduces the transient voltage by approximately 23%. Increasing the number of grounding conductors and decreasing the soil resistivity in the area can effectively suppress the transient voltage. The use of surge protectors

however

increases the transient voltage by 39%. Additionally

equipotential connections between photovoltaic brackets reduce the transient voltage by 20%. These findings are crucial for accurately evaluating the transient voltage of bypass diodes in centralized photovoltaic systems and for designing more effective lightning protection measures.