# Design Method of Primary Structures of a Cost-Effective Cable-Supported Photovoltaic System
## 1 Introduction
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**China**} & \multicolumn{2}{c}{**United States**} \\ \hline  & **Cost (USD)** & **Percentage** & **Cost (USD)** & **Percentage** \\ \hline PV modules & 0.27 & 46.76\% & 0.35 & 41.6\% \\ PV support and foundations & 0.07 & 11.99\% & 0.12 & 14.5\% \\ Inverter and grid box & 0.03 & 4.8\% & 0.04 & 4.5\% \\ Other fees & 0.21 & 36.45\% & 0.33 & 39.4\% \\ Total & 0.5775 & & 0.85 & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Investment cost percentage of solar farms [1; 2]. Figure 1: Fixed support PV structure system. pressure field and loads of ground-mounted PV modules via CFD simulations and showed that the interpanel gap and tilt angle affect the surface pressure. [PERSON] et al. [21] studied the influence of column height and estimated steady and unsteady wind loads on heliostats through a wind tunnel test. The results show that an increase in column height produces larger steady and unsteady pressure wind loads, stronger vortex shedding, and higher shedding frequencies. [PERSON] and [PERSON] [22], [PERSON] et al. [23], [PERSON] and [PERSON] [24], and [PERSON] et al. [25] conducted field measurements of the wind loads on PV modules. Recently, CSPSs have become popular because they save land resources and are cost-effective. [PERSON] et al. [26] first proposed a CSPS in their study; a sketch of the structure is shown in Figure 2. The CSPS has broad application prospects because of its light weight, few pile foundations, short construction period, good heat dissipation performance, large span, reduced land use, increased space utilization, and applicability to complex terrains [26; 27; 28]. Thus, the CSPS is an alternative solution that overcomes the drawbacks of conventional fixed-mounted PV systems. However, the original CSPS has high settlement because only two supporting cables bear self-weight, static wind loads, and/or snow loads. Reducing the settlement requires a higher pretension and larger cables. Moreover, the original CSPS is prone to strong wind-induced vibrations (WIV) because of its high flexibility. Recently, the authors proposed a new CSPS [30], as shown in Figure 3, and verified its wind resistance capability [31]. A single element of the new CSPS consisted of three cables, four triangular brackets, and several lateral connectors. The upper two cables support the PV modules, and the lower cable supports the two upper cables in the four sections through triangular brackets. The new CSPS has a larger span and smaller deflection. The lateral connectors enhance the wind resistance of the CSPS. Compared with the traditional fixed-tilt PV support system, the new CSPS saves 10-15 tons of steel and 100-180 pile foundations per MW [31]. Therefore, the new CSPS has great potential for wide applications. Over the past three years, more than 20 new cable-supported solar farms have been built in China with a total capacity of more than 1 GW. In addition, an increasing number of CSPS solar farms will be built in the coming years. To date, only China and Japan have published specifications [32; 33] for the structural design of ground-mounted PV modules. As previously reported by [PERSON] et al. [34],  
Figure 3: Sketch of the new CSPS. Figure 2: Cable-supported PV system proposed by [PERSON] [29]. \"Despite the current understanding of wind effects on ground-mounted multirow solar arrays, there is no comprehensive method in any building code/standard that provides appropriate guidance to practitioners designing these types of structures. Although numerous commercial wind loading studies on ground-mounted solar arrays have been carried out by wind tunnel laboratories worldwide, these data remain largely proprietary in nature and thus are not available in the public domain. Consequently, there is a need to establish a new design method for ground-mounted multi-row solar arrays... \" The study on the design method of CSPVs is rare [34; 35; 36].