30 Jul

Panel dust will impact long-running photovoltaic power generation systems

For long-running photovoltaic power generation systems, the impact of panel dust on it should 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.

Panel dust will impact long-running photovoltaic power generation systems

1. occlusion influence

Dust adheres to the surface of the panel, which can block light, absorb and reflect light.Omega Profile steel

The most important part is the blocking effect of light, which affects the absorption of light by photovoltaic panels, thus affecting the efficiency of photovoltaic power generation. Dust deposits on the light receiving surface of the panel assembly, which firstly causes the surface transmittance of the panel to decrease; secondly, the incident angle of part of the light changes, resulting in uneven propagation of light in the cover glass. Studies have shown that under the same conditions, the cleaned panel assembly has a higher output power of at least 5% compared to the ash assembly, and the higher the ash accumulation, the greater the component output performance degradation.

2.Corrosion effects

Most of the surface of the photovoltaic panel is made of glass. When the wet acidic or alkaline dust is attached to the surface of the glass cover, the surface of the glass will be eroded slowly, which will cause pits on the surface, causing the light to form a diffuse reflection on the surface of the cover. The uniformity of propagation in the glass is destroyed. The rougher the photovoltaic module cover is, the smaller the energy of the refracted light is, and the energy actually reaching the surface of the photovoltaic cell is reduced, resulting in a decrease in the power generation of the photovoltaic cell. And rough, viscous surfaces with adhesive residue are more likely to accumulate dust than smoother surfaces. Moreover, the dust itself will also absorb dust. Once the initial dust is present, it will cause more dust to accumulate and accelerate the attenuation of the photovoltaic cell power generation.

3. Temperature influence

At present, photovoltaic power plants mostly use silicon-based solar cell modules, which are sensitive to temperature. As dust accumulates on the surface of components, it increases the heat transfer resistance of photovoltaic modules and becomes a thermal insulation layer on photovoltaic modules, which affects heat dissipation. . After the component is blocked, it will induce the bypass protection component in the junction box behind it to start. The DC current of up to 9A in the component string will be instantaneously loaded onto the bypass device, and the junction box will generate more than 100 degrees of high temperature. High temperature has little effect on the panel and junction box in the short term, but if the shadow effect is not eliminated and exists for a long time, it will seriously affect the service life of the junction box and the panel. In industry news reports, the junction box is often burned and occlusion is one of the culprit.

The current and voltage of some battery cells in the solar cell module have changed. As a result, the product of the local current and voltage of the solar cell module is increased, thereby causing a local temperature rise on these battery components. Defects in some of the battery cells in the solar cell module may also cause the components to locally heat during operation. This phenomenon is called “hot spot effect”. When the hot plate effect reaches a certain level, the solder joints on the assembly melt and destroy the grid lines, resulting in the scrapping of the entire solar cell module. According to industry data, the hot spot effect reduces the actual life of solar modules by at least 10%.