# Design Method of Primary Structures of a Cost-Effective Cable-Supported Photovoltaic System
## 1 Introduction  
PV modules have been widely used to collect solar energy to generate clean renewable electricity, and solar farms have become one of the primary solutions to climate change. The China Photovoltaic Industry Association (CPIA) reported the latest 2021-2022 China PV Industry Development Roadmap [1], providing the latest initial full investment cost of China's ground-mounted solar farms. In the United States, the Solar Energy Industries Association (SEIA) and Wood Mackenzie reported the Q2 2022 US Solar Market Insight Executive Summary [2] and provided the full investment cost for different types of solar farms, including utility fixed-tilt and tracking solar farms. Table 1 compares the investment cost percentages of the fixed-tilt solar farms in the two countries. The results showed that PV modules and their supporting systems account for more than 55% of the investment cost of the entire solar farm. Support systems are key components of solar farms and directly affect the safety of PV modules and construction investment. The wind load is the control load of the PV systems. Therefore, the optimal design of wind-resistant PV modules and their supporting systems has always been a hot topic in the fields of wind, PV, and transportation engineering [3]. Most PV modules are supported by fixed structures, as illustrated in Figure 1. To accurately assess wind loads on PV modules, since the 1980s, many researchers have studied wind loads on fixed supporting structures for PV modules. [PERSON] et al. [4] described the wind loads on PV module arrays on top of residential buildings via wind tunnel testing and observed that the average wind load of the rear modules markedly decreased owing to the shielding effect of the building and windward PV modules. [PERSON] et al. [5] described the influence of the position of PV modules on the wind loads on both flat roofs and PV modules via wind tunnel testing. [PERSON] et al. [6] investigated the effects of array spacing on the shielding effect of the wind load on rooftp PV modules. [PERSON] et al. [7] studied the effect of roof parapets on the wind load on roof PV modules. In recent years, [PERSON] and [PERSON] [8], [PERSON] et al. [9], [PERSON] [10], and [PERSON] et al. [11; 12] investigated wind loads on PV arrays with different aspect ratios on flat roofs and showed that wind loads on PV modules are primarily affected by the width of the building. [PERSON] and [PERSON] [13] studied the influence of the geometric scale of roof PV modules on the wind pressure distribution and concluded that the geometric scale has a significant influence on the wind load of PV modules. For wind loads on ground-mounted PV modules, [PERSON] et al. [14] found that the wind load on leeward PV modules was 30% lower than that on the windward row through full-scale measurements and computational fluid dynamics (CFD) numerical simulations. In addition, they found that the CFD numerical simulation yielded similar wind pressure distribution rules to the full-scale measurement, but the pressure coefficients of the simulation results were smaller than those of the full-scale measurement. [PERSON] and [PERSON] [15] and [PERSON] et al. [16; 17] studied the influence of distance and spacing from the ground on the wind loads on PV modules and showed that increasing the distance between the modules produced stronger vortex shedding, resulting in a greater average and fluctuating wind loads. When two adjacent PV modules reach a certain distance, the drag coefficient of the leeward PV modules decreases to a minimum. [PERSON] and [PERSON] [18] and [PERSON] [19] studied the wind load of ground-mounted PV modules via wind tunnel tests and CFD numerical simulations under different model scales and wind field characteristics. Their results showed that the geometric scale of the model and the characteristics of the wind field had little effect on the average wind pressure coefficient but markedly affected the peak pressure coefficient. [PERSON] et al. [20] studied the wind