For long-running photovoltaic power generation systems, the impact of panel dust can not be underestimated. The dust on the surface of the panel has the function of reflecting, scattering and absorbing solar radiation, which can reduce the transmittance of the sun, reduce the solar radiation received by the panel, and reduce the output power. The effect is proportional to the cumulative thickness of the dust.
In addition, because the dust absorbs solar radiation, the photovoltaic panel can be heated, and the dust contains some corrosive chemical components, which also reduces the photoelectric conversion efficiency.
In the low rain period, the cell efficiency loss can reach more than 15% due to the accumulated dirt on the panel surface. Dirt and dust on the surface of the panel can reduce annual average power generation efficiency by 6%. In general, dust and dirt in the air include: dust, rain, and pollutants, and their presence causes a decrease in the output energy of the cell. Because dust particles have a large impact on the forward scattering of sunlight, the current loss of such centralized modules is usually much higher than that of decentralized ones.
At the same time, other parts of the photovoltaic panel will also be corroded by wet dust, such as joints, brackets, etc., the materials are mostly various types of metals, which may cause damage and safety after corrosion, which may be due to strong winds, earthquakes, etc. Natural factors are destroyed and the life of photovoltaic panels is reduced.
Shadow is the most taboo problem of photovoltaic power plants. Pay attention to design and installation, and pay attention to later operation and maintenance. Common shadows mainly include bird droppings, dust, shade, buildings, deciduous branches, etc…
Therefore, first of all, it is necessary to do the landmark survey work. You can choose the right location to install the PV modules. Try not to install the components in the sheltered place. In the unavoidable situation, choose a suitable component placement method to reduce the shadows and block the shadows. Impact. In the daily operation and maintenance process, it is more important to pay attention to the cleaning of photovoltaic modules and timely clean up foreign objects such as ash.
Speaking of the hot spot effect, many people are puzzled… but the problems hidden in it, the adverse effects of the lack of efficiency of photovoltaic modules can not be underestimated!
What is the “hot spot effect”? Under certain conditions, a solar cell component that is shielded in a series branch will be used as a load to consume energy from other illuminated solar cell components. The shaded solar cell component will heat up at this time, which is the hot spot effect.
The hot spot effect severely destroys the solar cell itself to some extent, and part of the energy generated by the illuminated solar cell may be consumed by the shielded cell. In addition, long-term untimely cleaning has a great impact on the service life of PV modules. Serious conditions are also the source of fire. The hot spot effect of photovoltaic power plants will directly lead to a 30% reduction in the service life of PV modules, which may cause component failure in the long run.
As a photovoltaic person, since the installation of photovoltaic power station, it is essential to develop scientific operation and maintenance habits, and master the scientific operation and maintenance methods. In view of the above-mentioned common problems of photovoltaic power plants, the small box will of course let everyone know the solution!
PV module operation and maintenance knowledge
At present, some photovoltaic power generation systems rely on natural effects such as rainfall and wind to remove the ash from photovoltaic panels. Some small photovoltaic power plants use manual cleaning methods, which are usually cleaned with a mop, rubber scraper or a soft rag.
Large and medium-sized photovoltaic power plants are difficult to clean manually, and mechanical cleaning is generally used. The high-pressure water gun is cleaned, and the water is pressurized to form a water vapor mixture. The dust on the surface of the photovoltaic panel is cleaned and the cleaning effect is good, so it is widely used in many photovoltaic power stations. In addition, there is a mechanical dust removal technology, which uses a mechanical brush combined with a water spray to wash the automatic dust removal device of the photovoltaic panel, and the dust is swept away by mechanical force.
Before the construction of photovoltaic power station, it is necessary to do a good job of preliminary exploration to determine whether there will be occlusion of surrounding high-voltage lines, railings, vegetation, existing buildings (planned buildings should be expected as early), to find ways to eliminate occlusion and change the installation location. .
Some people always think about what can be done for the power station, such as installing a fence, in order to drive the bird frame to drive the bird, this is a kind and positive move, but there is a counter-effect of “drawing the snake”, and some people lack the photovoltaic operation. Dimensional knowledge, in the photovoltaic components drying clothes, vegetables and other wrong practices, these behaviors will invisibly block the power station.
In order to avoid this factor, the performance of the PV module is reduced. This requires the construction project department to do the technical work before the construction, and strengthen the inspection of the project quality during the construction process. Only in this way can the situation be prevented from affecting the life of the component.
The measures in the production section of the module include: controlling the reverse current of the cell, controlling the impurities inside the cell, and using parallel diode protection for the components.
The measures on the application side include: using a cell (or component) with good performance consistency, ensuring that the components are not blocked during installation, and cleaning and cleaning in time when there is contamination, so that the photovoltaic system maintains good power output.