A solar photovoltaic flexible mounting system consists of photovoltaic (PV) modules installed on rows of steel cables (strands), with both ends of the cables supported by rigid structures. To reduce the bending moment at the top supports at both ends, external tensioned cable stays or internal rigid diagonal braces are commonly used. As a primary load-bearing component, the cable (steel strand) is characterized by high flexibility, low self-weight, and high stiffness
2.1 Introduction to Flexible Mounting Systems
A solar photovoltaic flexible mounting system consists of photovoltaic (PV) modules installed on rows of steel cables (strands), with both ends of the cables supported by rigid structures. To reduce the bending moment at the top supports at both ends, external tensioned cable stays or internal rigid diagonal braces are commonly used. As a primary load-bearing component, the cable (steel strand) is characterized by high flexibility, low self-weight, and high stiffness. The required stiffness is largely provided by prestressing. Cable structures exhibit the following characteristics:
They can only resist tension, not compression.
Their stiffness is mainly geometric stiffness, provided primarily by prestressing.
They behave linearly only when taut; otherwise, their behavior is nonlinear.
They are subject to stress relaxation and loss.
2.2 Advantages of Flexible Mounting Systems
Because cables primarily resist tension, their material strength can be fully utilized, making flexible PV mounting systems a preferred choice for designers.
Large span capacity and flexible span adjustability.
Maximized land use efficiency.
Flexible operation, good ventilation, and high power generation efficiency.
Better crack resistance compared to traditional PV mounting structures.
Lower steel consumption, reduced bearing load, and lower cost.
Lower foundation requirements and high prefabrication potential, significantly shortening the construction period.
2.3 Applicability of Flexible Mounting Systems
The flexible and space-saving characteristics of solar PV flexible mounting systems make them suitable for a wide range of applications. They can be used in complex terrains such as tidal flats, fish ponds, wastewater treatment plants, rugged mountainous areas, wastelands, and reservoir banks. Under the national policies promoting "fishery-solar hybrid" and "agriculture-solar hybrid" projects, flexible PV mounting systems have broad application prospects.
2.4 Structural System of Flexible Mounting Systems
The structural system of a flexible PV mounting system consists of two parts: the flexible system and the support system.
The flexible system comprises prestressed suspension cables, stabilizing cables, module fixing clamps, and PV modules.
The support system comprises foundations (including isolated foundations and pile foundations), steel columns, steel beams, and bracing systems (including cable stays and diagonal braces).
Depending on the load-bearing characteristics of the
solar PV mounting system, diagonal tie rods (cables) or diagonal braces are typically installed on both sides. When PV modules are subjected to wind or snow loads, the cables deform under tension, the steel columns resist vertical forces, and the cable stays or diagonal braces resist horizontal forces.
For PV power plants on wastewater treatment sites, where spans are often large, steel trusses are commonly added between the steel columns and intermediate supports to reduce the span and thus minimize deflection. On complex mountain slopes, cable stays (steel strands) are typically arranged along the natural slope before installing the PV modules. This not only utilizes the natural terrain but also achieves an aesthetically pleasing layout.
Concluding Remarks
Solar photovoltaic power generation enables effective utilization of solar energy. For structural engineers, designing a safe and economical support system is a key consideration. Flexible solar PV mounting systems are capable of adapting to harsh environments and complex terrain conditions, offering broad application prospects. However, various challenges remain regarding their wind resistance, which is a key concern for researchers and a matter of importance for designers. With increasing research efforts in the future, flexible solar PV mounting systems will undoubtedly drive the photovoltaic industry toward safer, more economical, and more durable development.
