# DC Cabling of Large-Scale Photovoltaic Power Plants
## 6 Conclusions  
This paper presents a general method for calculating the length and type of cables on the DC side of large-scale floating photovoltaic power plants. Power losses in cables are analyzed. It is demonstrated that losses are less than 0.55% for the topology with two types of cables and increase slightly with an increase in the power of the inverter. With a one-cable type topology, power losses are higher, up to 0.7%, and they increase faster with an increase in the power of the inverter. If the number of strings is greater than three, a topology with two types of cables should be used. If the number of strings is three or fewer, it is sufficient to use only one cable type. This paper develops a method for the calculation of cable lengths and power losses in cables, as well as a method for analyzing the techno-economic parameters of power plants, such as the number of modules, the number of inverters, the number of connectors, the number of blocking diodes, the required area, the cable types, the copper mass on DC cables, etc. For power loss calculation, this model considers the change in current and resistance as a function of temperature. The coefficient of change in the short-circuit current as a function of the temperature is given in the catalog. Still, the catalog does not provide data about the current change at the maximum power point. This paper shows how the current change can be determined at the maximum power point depending on the temperature. We obtain an expression for current and voltage calculation at the operating point as a function of temperature. To use that expression, a correction factor that multiplies the temperature coefficient of the current must be used. This factor slightly depends on the temperature change, and its average value is 1.734992. By applying this coefficient, the power calculation at the maximum power point differs from the value obtained using catalog data for \(k_{\mathrm{p}}\) by less than 0.09%. In this paper, only losses on DC conductors are analyzed. However, in the DC array, there are other losses that occur as a result of the system operating in real conditions. Parallel and series connections of solar modules in configurations adapted to the parameters of the used inverters lead to the equalization of currents of solar modules connected in a string and the equalization of voltages at the ends of strings connected in parallel operation. Any asymmetry, i.e., a deviation of the operating conditions of an individual solar module from the others in the group, reduces the performance of the system due to these equalizations. This reduction is manifested by the working point of the solar panels being moved beyond the point of the MPP due to alignment with the other panels in the array. This problem is especially pronounced when individual strings in parallel, or modules in a string, do not have the same insolation, i.e., when a shadow appears on a part of the plant. Significant losses then occur, and this problem is the subject of intensive research, where different wiring topologies are analyzed in terms of their potential to reduce these losses. In this paper, we have not dealt with this problem; instead, we assume identical conditions for all panels in the system. In addition, different string positions relative to the inverter require different cable lengths. This leads to different voltage drops on the cables, and losses occur due to voltage equalization in parallel connections. These losses are not large because differences in line lengths occur only on parallel connections that have larger cross-sections and shorter lengths. The problem is that these losses occur constantly and not occasionally, as in shading. In any case, the problems of losses due to voltage drops and shading are important and should be analyzed in future research. Conceptualization, A.A. and S.K. ; methodology, A.A., S.P. and S.O. ; investigation, A.A., S.P. and S.G.; data curation, S.K. ; software, S.O. ; visualization, S.O. and S.G.; writing--original draft preparation, A.A., S.K.