## 1 Introduction  
Recently, the renewable energy market has been growing rapidly, owing to fossil fuel reduction and environmental problems [1, 2]. With the expansion of the renewable energy market, the global photovoltaic (PV) capacity is projected to exceed 1 TW by 2022 [3]. Especially, the solar power market for large-scale PV power-generation systems with capacities in the range of MW or higher is expanding rapidly. However, it is difficult to secure land for the construction of such large-scale systems; hence, large-scale floating PV facilities have been proposed as high-efficiency alternatives [4]. As of 2018, 1314 MW of floating PV systems were installed worldwide, and it has been predicted that 5,211,086 GWh/y of electricity will be generated annually if 10% of the man-made reservoir surfaces are used for floating PV systems [5]. Various researches have accompanied the growth of the floating PV market. In Korea, as in many countries around the world, several kinds of research on floating solar systems are being conducted, such as research on the installation of floating PVs in oceans, the grounding of floating PVs, and tracing-type floating PVs that track sunlight [6; 7]. The floating PV system is a new concept of a power plant, which uses buoyant bodies to float solar power plants on the surfaces of dam reservoirs. The system is designed such that the solar module is fixed to a float that is secured by a mooring device on the water surface [8]. Figure 1 shows the concept of a typical floating PV system. The benefit of a large-scale floating PV system is that it can be installed in the reservoir of a dam without the need for deforestation, which is a common problem encountered while installing land-based PV systems. The first floating PV system was built in 2007 in Aichi, Japan, following which several other countries, including France, Italy, Korea, Spain, and the United States, installed small-scale systems for research and development (R&D) purposes [5]. Recently, PV systems have been widely deployed in many countries, and their capacity has increased to several tens of MW or higher. A 7.5 MW system and a 6.3 MW system on the Umenoki reservoir, Japan, and the Queen Elizabeth II Lake, UK, are currently in operation. In Huainan City, China, a 40 MW PV system is in operation [5; 9]. In Korea, a 100 kW demonstration floating PV system was installed, for the first time, on the water surface of the Hapcheon Dam reservoir, in October 2011. After successfully installing this PV system, a 500 kW commercial floating PV system was installed at another nearby location in 2012. As of 2020, the representative floating PV systems operating in Korea are a 2 MW system on the Boryeong Dam reservoir, a 3 MW system on the Chungju Dam reservoir, and an 18.7 MW system on the lagoon at the Gunsan Industrial Complex. Figure 2 shows the 3 MW floating PV system installed on the reservoir of the Chungju Dam, Korea. Figure 1: Concept of floating PV system. The power generation characteristics of PV modules are heavily influenced by the cell/module temperature [10]. Generally, the PV module output can be estimated as shown in Equation (1), and thus, the rating of a PV module may differ depending on the temperature differences from the actual site under the standard test conditions (STC), wherein the solar radiation intensity is 1000 W/m\({}^{2}\), the module temperature is 25 \({}^{\circ}\)C, and the air mass (AM) coefficient is 1.5 [11]. \[P=G_{T}\tau_{pv}\eta_{TraF}/A[1-0.0045(T_{c}-25)], \tag{1}\]  
where \(P\) is the output power of the PV module [W], \(G_{T}\) is the solar irradiance on the module plane [W/m\({}^{2}\)], \(\tau_{pv}\) is the transmittance of the PV cells' outside layers, \(\eta_{TraF}\) is the electrical efficiency of the module at a specified temperature, \(A\) is the surface area of the PV module [m\({}^{2}\)], and \(T_{c}\) is the module operating temperature [\({}^{\circ}\)C].