Factors affecting the power generation efficiency of photovoltaic modules

With the increase of photovoltaic installed capacity, the system power generation efficiency of photovoltaic power plants has gradually become the focus of attention. Through the research and analysis of the existing photovoltaic power station operation data, it is found that the main reasons affecting the efficiency of the photovoltaic power generation system are the abnormal power of photovoltaic modules, foreign object occlusion, string mismatch, equipment failure, and components that appear during the operation of photovoltaic modules. failure, tempered glass breakage, hot spot effect, etc. These reasons will reduce the power generation efficiency of the photovoltaic power plant system. 1. Abnormal power of the module: The main performance is that the power of a single module is quite different, and the factors that cause it include cell cracking, internal grid line breakage, abnormal cell attenuation, and cell mixing. 2. Foreign body occlusion: It is caused by fallen leaves, bird droppings, and surrounding objects. Long-term occlusion will cause the cells in the occluded part to heat up to form hot spots, and at the same time corrode the outer tempered glass. 3. Mismatch between strings and parallels: It is mainly manifested that the output voltage and current of the strings under the same conditions are quite different, and the output voltages are inconsistent, which reduces the MPPT tracking accuracy of the inverter and the efficiency of the inverter. The main reason is the string Shade, the inconsistent azimuth angle of the square array, mixed power installation of components, etc. 4. Equipment failure: The main manifestation is that the branch string does not work. Due to a large number of access channels of the combiner box, if the monitoring is not in place, it is difficult to find out after a single inverter loses a few strings, so it is necessary to conduct regular convergence. 5. Module failure: The main reason is that the module has no power output due to the failure of the module junction box and the rupture of the internal conductive grid wire. If a single module fails completely, it can be regarded as a breakpoint in the string, resulting in no power generation for the entire string of modules. 6. Glass breakage of photovoltaic modules: The tempered glass will break during the operation of the module. The reason may be that the glass is damaged by an external force during the handling process, and the damaged module expands due to the temperature rise during operation, causing the module to be damaged. Glass breakage occurs. At the same time, the abnormal air pressure caused by the sonic boom of the aircraft can also cause the glass to break. Components with broken glass have the risk of leakage during operation, which increases the probability of fire and poses a great safety hazard. 7.Module hot spot: Hot spot is a common defect in photovoltaic power plants. When the hot spot is serious, it will cause the power attenuation of the module to fail or directly cause the module to be burned and scrapped. The hot spot needs to be judged by infrared thermal imagers and other equipment. For the above-mentioned situation that the efficiency of the photovoltaic power station system fails to meet expectations, we first need to figure out what is the reason, and then the operation and maintenance unit should improve the management standards and regularly benchmark the daily operation and maintenance, maintenance, and data analysis of the power station; In the operation monitoring of power generation equipment, regular inspections are carried out with the help of various advanced technologies, which have a positive effect on our ability to master the operation status of the power station. The second is to technically improve the operation and maintenance standards, conduct regular inspections of power generation equipment, and eliminate defects found in a timely manner, such as regularly removing shading weeds in the field, and increasing the frequency of component cleaning. Finally, according to the operation of the equipment, technical transformation and economic demonstration of the equipment can be carried out. In this way, one is to ensure that the power generation equipment does not appear "barrel effect" and improve the efficiency of the equipment; the other is to carry out an economic demonstration on the health status and replacement of old and new equipment. , maximize the protection and improve the recovery efficiency of power generation.

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