What is the design of the photovoltaic array?
For the design of the DC part of a large scale centralized grid connected photovoltaic power station, the most important thing is the design of the photovoltaic array, because the main part of the power station is the photovoltaic array. It is composed of a square array in an orderly arrangement, and the square array is formed by a certain number of photovoltaic modules connected in series and parallel. Therefore, the design sequence should be from the selection of components to the design of the square array and then to the design of the square array and corresponding brackets, foundations, and connecting cables.
(1) Selection of solar cell modules
Large scale centralized grid connected photovoltaic power station mostly use high-efficiency crystalline silicon solar cell modules. Thin-film solar cells with higher efficiency and relatively stable performance have also been demonstrated in applications.
Due to the rapid development of polycrystalline silicon solar cells in China in recent years, domestic high-efficiency polycrystalline flat-panel battery modules are mostly used by large-scale photovoltaic power stations. In particular, the power of a single module is 280Wp, and the battery efficiency reaches 17%~18%. It has passed ISO9001 quality system certification and UL, TUV. A series of international certifications such as, IEC, etc., can ensure that the output power of photovoltaic modules reaches more than 25 years, and the battery efficiency and stability are at the world’s advanced level.
In the construction of large-scale photovoltaic power generation systems, commercially available high-quality 240Wp or 260Wp polycrystalline silicon solar cell modules are often used. The characteristics of such modules are:
①The high-quality and firm aluminum alloy frame can resist strong wind, freezing and no deformation.
②The novel and special frame design further strengthens the sealing between the glass and the frame.
③The long and short sides of the aluminum alloy frame are equipped with installation holes to meet the requirements of different installation methods.
④ The low-iron super-translucent glass with high light transmittance enhances impact resistance.
⑤High-quality EVA material and back electrode material.
It should be emphasized here that for solar cell modules used in photovoltaic power stations built on beaches and islands, necessary technical demonstrations and necessary measures must be taken to prevent sea breeze and salt erosion from affecting power generation and service life.
It should be noted here that with the large-scale use of photovoltaic modules, it is found that there are mainly quality problems such as hot spots, hidden cracks and power attenuation. When choosing photovoltaic modules, we must check the price instead of just paying attention to the price.
In particular, the “Potential Induced Degradation” (PID, Potential Induced Degradation) of photovoltaic modules caused significant degradation of some photovoltaic power plants after a period of operation, which led to more and more discussions in the photovoltaic industry on the causes and prevention methods of PID. . Some families and regions have gradually begun to regard PID as one of the key requirements for components. Many users in Japan clearly require that anti-PID be included in the contract. There is no clear conclusion about the real cause of the PlD phenomenon so far. It is clear that the PID phenomenon is related to the reflective layer on the surface of the cell. Increasing the refractive index of the reflective layer can effectively reduce the occurrence of the PID phenomenon.
Design principle of solar photovoltaic power generation system.You can learn more.