The influence of design on power generation is very important, and an excellent system integration scheme plays an important role in improving the efficiency of photovoltaic power plants. Mainly explain the core technology of high-efficiency photovoltaic power generation engineering design from the aspects of photovoltaic modules, inverter selection, photovoltaic array operation mode, module inclination and array spacing comprehensive calculation technology, photovoltaic power generation unit maximum power generation design, confluence cable configuration, etc. , Proposed a number of design techniques that are conducive to improving the power generation efficiency of the system, and conducted detailed and in-depth explorations in each aspect to effectively improve the efficiency of photovoltaic power stations and reduce construction costs.
(1) There are many power specifications of photovoltaic modules, but when selecting the type, the solar cell modules with large single power and commercial applications are generally considered. This site introduces some common module types at present, and offers Suggestions for component selection.
(2) The photovoltaic power generation system is connected to the grid or load through inverters with various technical structures. Due to the diversity of applications, it will inevitably lead to the diversity of photovoltaic module installations. In order to maximize the efficiency of the photovoltaic power generation system while taking into account economic benefits, this requires the diversification of inverters to achieve the best way of solar conversion. Each type of photovoltaic inverter has unique advantages and disadvantages, and there is no absolute use restriction. It should be selected reasonably in combination with the construction conditions and construction goals of each project, such as the largest power generation and the lowest power generation cost.
(3) The selection of the operation mode of photovoltaic power stations requires comprehensive consideration from several aspects such as initial investment, power generation, and operation and maintenance costs. The working characteristics of the four types of optimal tilt angle fixed type, single-axis tracking type, dual-axis tracking type, and concentrating tracking type are analyzed, as a reference basis for selecting the operation mode of photovoltaic power plants.
(4) Determining the boundary conditions and optimization objectives of the photovoltaic power station module inclination angle and array spacing involves many factors. In addition to the local radiation intensity, the boundary conditions also include the shadow loss of the modules throughout the year, the amount of DC cables of the photovoltaic power generation unit, and the photovoltaic array. Coverage area, DC cable line loss, etc. The optimization goals include the largest power generation, the smallest total investment, and the smallest static investment per unit of electrical energy. With the goal of minimizing the static investment per unit of electricity, a cost model for determining the optimal inclination angle of the module and the optimal spacing of the array is established, and the cross-feedback comprehensive calculation of the module inclination angle and the array spacing is carried out.
(5) From the perspective of photovoltaic power generation unit layout, analyze the shape of the photovoltaic power generation unit, the layout of the centralized inverter and the road in the square array, the capacity ratio of the photovoltaic module and the inverter, etc., and propose to improve the photovoltaic power generation unit Design method of output power.
(6) In view of the long distance between photovoltaic module strings, combiner boxes, inverters and other equipment in photovoltaic power generation projects, and the large amount of cables, a differentiated configuration technology for long-distance DC bus cables is proposed, and different cross-sections are used according to the distance. The primary bus cable and secondary bus cable, on the one hand, reduce the loss of the bus line while ensuring economy, on the other hand, make the voltage drop of the DC cable tend to be consistent, so that as many photovoltaic modules as possible work at the maximum power output point. Improve the energy utilization rate of the photovoltaic power generation system and increase the output power of the photovoltaic power generation system.
(7) Taking the geological conditions of the area where the power station is located as the starting point, fully considering the control factors of different foundation forms, materials, construction techniques and construction costs, and comprehensively selecting basic types that not only meet the structural safety requirements, but are also economical and practical.
(8) For photovoltaic power stations installed on the ground, roof and water surface, the design points that should be paid attention to in the reliable lightning protection grounding design are proposed to reduce or avoid damage to the equipment in the photovoltaic power station by external overvoltage and internal overvoltage. And to ensure personal safety.
(9) Briefly introduce the requirements, data management, team and rules and regulations in the operation and maintenance of photovoltaic power stations, so that designers can have a preliminary understanding of the processes and characteristics of operation and maintenance of photovoltaic power stations, and provide a combination of later operation and maintenance and optimization of the design work in the early stage. Base.
(10) Select a representative photovoltaic power station project case, briefly introduce the design characteristics of the representative case, and provide design ideas for photovoltaic designers.
(11) The rapid development of floating water surface photovoltaic projects worldwide.