Not only is the power generation reduced! On the influence of shadow shading on photovoltaic power generation

发布日期:According to calculations, the slight shade of trees and wires in the photovoltaic system can cause the power generation of the power station to be reduced by about 20-30%!    At present, the construction of photovoltaic power plants on the roofs of rural households and industrial and commercial buildings has become a popular trend. The amount of photovoltaic power generation directly affects the final profit, and shadow shading is one of the most common problems affecting power generation.
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According to calculations, the slight shade of trees and wires in the photovoltaic system can cause the power generation of the power station to be reduced by about 20-30%!
 
   At present, the construction of photovoltaic power plants on the roofs of rural households and industrial and commercial buildings has become a popular trend. The amount of photovoltaic power generation directly affects the final profit, and shadow shading is one of the most common problems affecting power generation.
 
   Photovoltaic shadow shading cannot be underestimated
 
  So, how much influence does shadow occlusion have on power generation?
 
In many rooftop photovoltaic power stations, many owners often cannot completely avoid the shadows in order to install them all at once, because the owners feel that the area covered by the shadows is not large anyway, and the impact should not be great, but in fact, people often Ignore the power of small shadows. According to calculations, the slight shade of trees and wires in the photovoltaic system can cause the power generation of the power station to be reduced by about 20-30%!
 
  Under certain conditions, part of the cells in the photovoltaic system will be blocked by other objects around, causing partial shadows, which will cause some cells to generate heat and produce the so-called "hot spot" phenomenon. If the shadow effect is not eliminated and exists for a long time, when the hot spot effect reaches a certain level, the solder joints on the module will melt and destroy the grid line, which will lead to the scrap of the entire solar cell module. Obviously, the shading seriously affects the service life of the junction box and the battery panel, and at the same time seriously affects the power generation and reduces the owner's income.
 
The more common photovoltaic shadow shading source
 
1. Wires and guardrails
 
   Although the scope of construction of photovoltaic power plants is fixed, the environment around the power plant is diverse. Even a very professional system design company will ignore the invisible shielding of wires and power plant guardrails.
 
2. Fixed buildings
 
   There are two types of buildings here: one, the existing building shelter before the construction of the power station; the second, the building shelter built the day after tomorrow.
 
3. Plants near the photovoltaic power station
 
   When the photovoltaic power station was built, there were no plants nearby, but later, new plants will grow, and these plants will play a role in sheltering the power station.
 
Four, bird droppings and dust
 
Photovoltaic modules are often built on the roof and on the ground. For photovoltaic power stations placed outdoors, it is easier to attract dust. When the modules are covered with a layer of dust, don’t underestimate this layer of dust. It will also affect the power generation of photovoltaic modules. It is very large, and photovoltaic modules will also become a place for birds to "play". Bird feces and scattered bird feathers become frequent visitors on photovoltaic modules.
 
Five, sun-dried peppers, sun-dried sweet potatoes, etc.
 
   Previously, someone posted on the Internet that a user was drying hot peppers and sweet potatoes on photovoltaic modules, which has become a hot topic in the industry. Although this "funny act" has facilitated the lives of ordinary people, it has brought serious harm to photovoltaic power plants.
 
How to avoid photovoltaic shadow occlusion
 
   1. Pay attention to shadow analysis before power station construction
 
Before the construction of the photovoltaic power station, it is necessary to do the preliminary survey work to determine whether the surrounding high-voltage lines, railings, vegetation, and existing buildings (planned buildings should also be anticipated) will be blocked, find ways to eliminate the blocking and change the installation location .
 
   In the survey and installation, the growth year of the plants should be fully considered, and the shade, branches and leaves should be considered as shades. If there is shade, it can be cut down.
 
   There are also topographic differences to consider whether the component north-south and east-west components cause shadow occlusion; different sub-array heights of the same row of square arrays cause occlusion; at the same time, the shadows between floors should also be considered.
 
  2, clean the surface of photovoltaic modules
 
The shadow occlusion is mainly due to the influence of bird droppings, dust, shade, etc., so first of all, we can choose a suitable location to install the photovoltaic module, and try not to install the module in the shaded place. If it is unavoidable, choose a suitable one. The placement of components can reduce the impact of shadows caused by occlusion. In daily operation and maintenance, pay attention to the cleaning of photovoltaic modules, and timely clean up dust and other foreign objects.
 
   3. Avoid man-made occlusion
 
Some people always think about what they can do for the power station, such as installing fences and setting up bird repellent poles in order to drive away birds. This is a kind and positive action, but there is a counterproductive effect of "superfluous", and some people lack photovoltaic power. Weizhi, wrong practices such as drying clothes and vegetables in photovoltaic modules, these behaviors will invisibly bring shelter to the power station.
 
  4. Use multi-channel MPPT inverter
 
   Considering the system itself, the realization of multi-channel MPPT will reduce the influence of shadow occlusion. For example, the micro-inverter photovoltaic system is a fully parallel design circuit, each module has an independent MPPT, which can achieve the maximum power output, so that shadows, dust, and leaves partially block the battery panels, no longer have short-board effects, and eliminate The mismatch problems caused by the different shades, orientations and angles of the components greatly increase the power generation. But based on this type of system, each solar panel is equipped with an inverter, and the cost is also relatively high. It can only be said that based on site conditions and basic calculations, if the cost budget allows, using this system can avoid site restrictions and bring higher power generation efficiency and benefits, that is a good choice.
 
   Photovoltaic power plants are easy to build, but the shading problem should not be underestimated. If photovoltaic power plants can achieve the expected benefits, these shading problems must be paid attention to early. Only in this way, photovoltaic power plants are not the "flower vase" in the user's home, and truly become the user's "money cow".
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