A manufacturer of surge protective devices explains the pathways through which lightning can intrude into photovoltaic power generation systems and the corresponding lightning protection measures for PV systems.

　　Surge Protective Device Manufacturer: Lightning Intrusion Paths into Photovoltaic Power Generation Systems and PV Lightning Protection Measures

　　Since the main components of a solar photovoltaic power generation system are located outdoors, they are susceptible to lightning strikes or induced high-voltage surges, which can lead to equipment damage. In this article, the editor from a surge protective device manufacturer will explore photovoltaic lightning protection by examining the pathways through which lightning and surge energy enter the system and the corresponding mitigation measures.

　　Surge Protective Device Manufacturer: I. Pathways for Lightning Surge Intrusion into Photovoltaic Power Generation Systems

　　(1) Ground potential rise voltage can intrude through the grounding system. When lightning strikes a lightning rod, a radial potential distribution is generated in the vicinity of the rod’s grounding electrode, causing the ground potential of nearby electronic equipment grounding systems to rise due to backflash. The resulting intrusion voltage can reach tens of thousands of volts.

　　(2) DC input line intrusion into the solar array; this type of intrusion can be categorized into the following two scenarios.

　　(1) When the solar array is struck by a direct lightning strike, the high-voltage surge can penetrate the insulation of adjacent soil or DC input cables, allowing lightning-induced surges to enter the photovoltaic system.

　　When a charged cloud discharges to the ground, the entire photovoltaic array, acting as a massive array of ring antennas, induces overvoltages on the order of several kilovolts, which are then coupled into the DC input lines and can damage the PV system equipment connected to those lines.

　　(3) Intrusion of the photovoltaic system’s power supply lines: When power supply equipment and lines are struck by lightning, the resulting overvoltage on the power lines can average tens of thousands of volts. The output lines also serve as a major pathway for induced lightning surges, with lightning pulses propagating along the power lines and entering photovoltaic microelectronic devices and systems, potentially inflicting catastrophic damage.

　　Surge Protective Device Manufacturer: II. Lightning Protection Measures and Design Requirements for Solar Photovoltaic Power Generation Systems

　　(1) In locations and situations prone to lightning strikes, the site selection for solar photovoltaic power generation systems or plants should be avoided as much as possible.

　　(2) Avoid, as much as possible, having the shadow of the lightning rod fall on the solar array modules.

　　(3) Depending on site conditions, various protective measures such as lightning rods, lightning strips, and lightning meshes may be employed to protect against direct lightning strikes, thereby reducing the probability of lightning strikes. Whenever possible, several down conductors should be evenly distributed to channel the lightning current into the ground; the current-diversion effect of multiple down conductors can reduce the voltage drop along each conductor, lower the risk of side flashes, and diminish the magnetic field intensity generated by discharge from the down conductors.

　　(4) To prevent lightning-induced surges, all metallic components of the photovoltaic power generation system— including the frames of solar modules, equipment, enclosure/cabinet housings, and metal conduits—shall be equipotentially bonded to the combined grounding electrode and provided with independent grounding, thereby ensuring equipotential bonding throughout the photovoltaic system.

　　(5) Install surge protective devices (SPDs) in a cascaded configuration along the system’s electrical circuits to implement multi-level protection, enabling lightning strikes and switching surges to be diverted through successive stages of SPDs. In photovoltaic power generation systems, DC circuit sections typically employ DC power SPDs, while AC circuit sections after inversion use AC power SPDs; the application of SPDs in solar photovoltaic power systems.

　　The foregoing discussion by the editor of the signal surge protector manufacturer has outlined the pathways through which lightning can intrude into photovoltaic power generation systems and the corresponding lightning protection measures. We hope this information proves helpful.