Photovoltaic modules are an important part of the system. They are not afraid of rain and lightning. They have strong "strike resistance", but there are two things that will have a bad impact on the "health" of photovoltaic modules. If not prevented, it can be said to be a problem for the modules. deadly!
Photovoltaic modules are most afraid of these two things. Do you know what they are?
First: Hot spots of components
What is hot spot? Under certain conditions, a solar cell module that is shaded in a series branch will be used as a load to consume the energy generated by other solar cell modules with light. The shaded solar cell module will generate heat at this time, which is the hot spot effect.
This effect must not be underestimated, it will cause serious damage to solar cells. Part of the energy produced by solar cells with sunlight may be consumed by cells that are shaded. In order to prevent the solar cell from being damaged due to the hot spot effect, it is best to connect a bypass diode in parallel between the positive and negative poles of the solar cell module to prevent the energy generated by the light module from being consumed by the shaded module.
Second: Affect the efficiency of component power generation-shadow
Shadows are the most taboo problem of photovoltaic power plants. Pay attention to calculating the impact of shadows during design and installation, and pay more attention to timely handling of shadow occlusion issues during later operation and maintenance. If the photovoltaic system is shaded by the roof and surrounding buildings, the power generation rate of the system will be reduced, which will affect the revenue of power generation.
The shadow occlusion of photovoltaic power plants mainly comes from the following items: array occlusion between modules, and obstacle occlusion in the distant and close-range scenes. Taking distributed rooftop power stations as an example, near-view occlusion includes roof parapets, gas towers, and other roof building occlusions, and long-term occlusion includes occlusion of telephone poles around the project and occlusion of adjacent buildings.
For the occlusion of obstacles (including parapets, gas towers, roof buildings, etc.), calculation and analysis of the shadow length of the obstacles in all directions on the horizontal plane can be used.
In addition to shadow calculation and analysis, the selection of inverters and the connection and arrangement of strings can also reduce the impact of shadow occlusion. Since the string on the DC side is composed of several components connected in series, the components blocked by the shadow will affect the output power of the entire string. The independent MPPT in the inverter can keep the input strings from being affected by each other, eliminate the inconsistency and mismatch of string power caused by shadow shading, retain the power generation to a greater extent, and reduce the loss of power.
In addition, common shadows include bird droppings, dust, tree shade, buildings, fallen leaves and branches, etc. Then you can choose a suitable location to install photovoltaic modules. Try not to install modules in shaded places. It is unavoidable. Choosing an appropriate component placement method can reduce the impact of shadows caused by occlusion. In the daily operation and maintenance process, pay attention to the cleaning of photovoltaic modules, and timely clean up dust and other foreign objects.
For users, in addition to developing scientific operation and maintenance habits, they must also master scientific methods and conduct regular inspections of photovoltaic arrays. Once obstructions are found, they must be removed in time to avoid malfunction of photovoltaic modules during operation. Suffer before it happens.