How can we improve the overall seismic performance of fasteners in photovoltaic arrays? This requires a systematic, comprehensive strategy that addresses multiple aspects—including fastener selection, design, installation, maintenance, and system coordination—to effectively address the challenges posed by dynamic loads such as earthquakes.
First, what should be done? The answer begins with scientific material selection and optimized design. For fasteners in photovoltaic arrays—such as bolts, nuts, clamps, and bracket connectors—the mechanical properties of the materials themselves form the foundation of seismic resistance. Priority should be given to high-strength, high-toughness, and corrosion-resistant materials, such as high-strength stainless steel or carbon steel treated with special surface corrosion protection (e.g., hot-dip galvanizing or Dacromet coating). These materials not only resist long-term environmental corrosion and prevent strength degradation caused by corrosion but also maintain good ductility under the alternating stresses generated by earthquakes, thereby preventing brittle fracture. In terms of design, the structure of fasteners must undergo specialized seismic calculations and simulation analyses to ensure they can withstand combined tensile, compressive, shear, and torsional forces at the design intensity. For example, anti-loosening designs (such as lock nuts with nylon inserts, S-lock thread structures, or combinations of double nuts with spring washers) are key to preventing loosening caused by vibration. The design of clamping fixtures should fully consider the compatibility of the component frames and the uniform distribution of clamping force to avoid stress concentration. At the same time, incorporating elastic elements with a certain degree of deformation capacity or damping designs can absorb and dissipate seismic energy within a certain range, thereby reducing the forces transmitted to the main structure.
Second, what should be done? The key lies in precise and standardized installation procedures. Even the most excellent fasteners will see their performance significantly compromised if installed improperly. Construction must strictly adhere to design drawings and installation specifications. This includes using calibrated torque wrenches to ensure every bolt reaches the preset tightening torque value. Insufficient torque leads to loose connections, while excessive torque may cause the bolt to yield or damage the threads—both of which severely weaken seismic resistance. For bolts in critical areas, it may even be necessary to consider using the torque-angle method for more precise control. During installation, ensure that connection surfaces are clean and level to prevent loss of preload due to debris or unevenness. Furthermore, the installation accuracy of the entire mounting system is critical. It is essential to ensure that the verticality of the columns, the levelness of the crossbeams, and the overall geometric dimensions meet specifications, allowing loads to be transferred along the designed path and avoiding the generation of additional secondary stresses.
Furthermore, what should be done? It is essential to prioritize the seismic coordination between the mounting system and the foundation. Fasteners do not exist in isolation; they serve as critical connection points linking photovoltaic modules, mounting systems, and foundations. To enhance overall seismic performance, fasteners must be considered within the context of the entire structural system. The structural configuration of the mounting system (e.g., fixed, adjustable, or tracking) and its mechanical model directly influence the stress state of the fasteners. During design, calculations should ensure that the mounting system possesses sufficient stiffness, strength, and overall stability, and its natural frequency should avoid the site’s dominant seismic frequencies to prevent resonance amplification effects. The connection and fastening between the foundation and ground anchors are of paramount importance. Based on geological survey reports, appropriate foundation types (such as concrete foundations, screw piles, or micro-hole cast-in-place piles) must be selected, and it must be ensured that the anchorage depth, specifications, and corrosion protection of anchor bolts or embedded parts meet seismic requirements. The entire system, from components to foundations, should form a complete structure with clearly defined load-bearing mechanisms and load transfer paths, with fasteners serving as reliable “joints” within it.
So, what should be done? Strict quality control and full-lifecycle maintenance are essential. From pre-shipment quality inspections of fasteners (including material reports, mechanical property testing, and corrosion-resistant coating inspections) to on-site acceptance upon arrival, every step must be rigorously enforced. It is recommended to establish a quality traceability record for critical fasteners. During the operation of a PV power plant, regular inspection and maintenance plans should be formulated. Particularly after extreme weather events such as strong winds or earthquakes, a comprehensive inspection of the array’s fasteners must be conducted to check for signs of loosening, deformation, corrosion, or fracture. Diagnostic tools such as torque wrenches and ultrasonic testing should be utilized. For fasteners found to be defective, they should be tightened, replaced, or otherwise reinforced in a timely manner. Regular maintenance not only eliminates safety hazards immediately but also accumulates data, providing a basis for optimizing future design and operations and maintenance.
Finally, what should be done? We must rely on technological innovation and the refinement of standards. The industry should actively research, develop, and apply new types of high-performance seismic-resistant fasteners, such as shape-memory alloy fasteners and smart bolts (capable of real-time monitoring of preload status). At the same time, efforts should be made to establish and refine specialized standards and specifications for the selection, design, construction, and acceptance of fasteners in photovoltaic power plants, particularly those built in earthquake-prone areas. Seismic performance should be incorporated as a core metric into the evaluation system, guiding the industry chain to upgrade from “meeting basic functional requirements” to “ensuring safety and reliability throughout the entire lifecycle.”
In summary, enhancing the overall seismic performance of photovoltaic array fasteners is a systematic endeavor that spans the entire process of design, manufacturing, installation, and operation and maintenance. How can this be achieved? The answer lies in selecting high-quality, seismic- and corrosion-resistant materials with anti-loosening designs; implementing precise and standardized installation procedures; ensuring that the mounting structures and foundation systems bear loads in concert; conducting rigorous full-cycle quality monitoring and maintenance; and continuously driving technological innovation and the development of standards. Only by doing so can every component of the PV array be securely fastened, ensuring it remains standing firm even during violent earthquakes, safeguarding the long-term safe and stable operation of the power plant, and laying a solid foundation for the clean energy sector.
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