Dust monitor for photovoltaic power station

1. Dust monitor for photovoltaic power station product overview

The Dust monitor for photovoltaic power station is a device used to monitor the dust on the surface of photovoltaic panels of photovoltaic power stations.Contaminants on the glass of solar modules are one of the main problems that quickly affect photovoltaic power plants, reducing power generation efficiency and cost performance. Dust pollution will significantly reduce the power generation of photovoltaic power stations, estimated to be at least 5% per year. Using blue light pollutant optical closed-loop measurement (OMBP) technology, it can be easily installed into new or existing photovoltaic arrays and integrated into power station management systems. The device is mounted on the frame of the photovoltaic panels. By continuously measuring the transmission loss caused by contaminants on the glass, the reduction in sunlight reaching the solar module is calculated.

By measuring the proportion of pollutants (SR), it is converted into a loss of power generation in real time. This allows operations personnel to know when contaminants have reached a critical point and it is necessary to start cleaning procedures. The product requires no maintenance, just clean it in the same way you clean surrounding components.

Because large photovoltaic power plants have different contamination rates throughout the park, multi-point measurements are required in the IEC 61724-1 standard. The purchase, installation and maintenance costs are much lower compared to traditional systems, making it more economical so cleanup can be planned when and where needed.

2. The impact of dust on photovoltaic power generation

Everyone knows that dust covers the components, forming a blocking phenomenon, which directly leads to a decrease in the power output of the components. Moreover, long-term adhesion of dust has a certain corrosive effect on the components. At the same time, the constant presence of dust will cause hot spots on the components, further reducing the output power of the components and even affecting the life of the components. Moreover, the hot spot effect is irreversible for components. Once there is no way to compensate, the only option is to replace the components. Otherwise, it will affect the power generation and may also bring safety hazards to the power station.

Many domestic and foreign investigation agencies have conducted research on the impact of dust on the power attenuation of photovoltaic systems, and the data obtained are shown in Figure 1.

As can be seen from the figure above, the output power of my country's photovoltaic systems is affected by dust by an average of about 20%.

The impact of dust on photovoltaic power generation mainly boils down to the following three aspects:

1. Temperature influence

At present, photovoltaic power stations mostly use silicon-based solar cell modules. This module is very sensitive to temperature. As dust accumulates on the surface of the module, it increases the thermal resistance of the photovoltaic module and becomes a heat insulation layer on the photovoltaic module, affecting its heat dissipation. .

Research shows that when the temperature of solar cells increases by 1°C, the output power decreases by approximately 0.5%. Moreover, when the battery module is exposed to long-term sunlight, the covered part heats up much faster than the uncovered part, resulting in dark spots where the temperature is too high and burns out.

Under normal illumination conditions, the covered part of the panel will change from a power generation unit to a power consumption unit, and the covered photovoltaic cell will become a load resistor that does not generate electricity, consuming the power generated by the connected battery, that is, generating heat. This is the hot spot effect. This process will aggravate the aging of the battery panels, reduce the output, and in severe cases may cause the components to burn out.

2. Impact of occlusion

Dust attached to the surface of the battery panel will block, absorb and reflect light, the most important of which is the blocking of light. The reflection, absorption and blocking effect of dust particles on light affects the absorption of light by photovoltaic panels, thereby affecting the efficiency of photovoltaic power generation.

Some studies have pointed out that dust deposited on the light-receiving surface of the battery panel component will firstly reduce the light transmittance of the panel surface; secondly, it will change the incident angle of some light, causing the light to spread unevenly in the glass cover.

Studies have shown that under the same conditions, the output power of clean solar panel components is at least 5% higher than components with dust accumulation, and the higher the amount of dust accumulation, the greater the decline in module output performance.

3. Corrosion effects

The surface of photovoltaic panels is mostly made of glass. The main components of glass are silica and limestone. When moist acidic or alkaline dust adheres to the surface of the glass cover, the components of the glass cover can react with acid or alkali.

As the time of glass in an acidic or alkaline environment increases, the surface of the glass will be slowly eroded, forming pits on the surface, causing diffuse reflection of light on the surface of the cover, and destroying the uniformity of propagation in the glass. , The rougher the photovoltaic module cover, the smaller the energy of refracted light, and the actual energy reaching the surface of the photovoltaic cell is reduced, resulting in a reduction in the power generation of the photovoltaic cell. And rough, sticky 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 exists, it will lead to the accumulation of more dust and accelerate the attenuation of photovoltaic cell power generation.

3. Dust monitor for photovoltaic power station product features

1. Real-time data monitoring: can collect and analyze four types of data: pollution ratio, cleanliness ratio, dust thickness, and backplane temperature. Dual probes are used for pollution ratio and cleanliness ratio.

Mean data calculation mode ensures accurate and reliable data.

2. Technology-based collector: The dust environment data collector adopts a new generation 32-bit MCU processor and integrates high-precision 4G and Bluetooth digital chips on the board, which allows the collected data to be sent to the data monitoring platform through wired or wireless methods.

3. Innovative blue light technology: Using a new generation of blue light pollutant optical closed-loop measurement (OMBP) technology, it can effectively ensure high-precision dust data detection and effectively prevent sunlight from interfering with the optical path closed-loop collection data. It can be used for a long time under all-weather conditions, which is better than the requirement in the "IEC 61724-1 Standard" that it can only be effectively monitored for three hours from 11 to 13 o'clock every day.

4. Smart power station cleaning: Built-in a new generation of IoT management and control module, with four control modes: normally open and normally closed, cycle control, time control, and manual control. According to the set pollution threshold and control mode, cleaning robots or IoT management and control equipment can be linked to automatically clean panel dust to ensure the high-efficiency power generation of photovoltaic power stations.

5. Accuracy self-calibration: The device integrates a one-click accuracy self-calibration button. Depending on different application environments and different usage times, the device's collection accuracy will decrease. The blue light monitoring circuit can be automatically recalibrated through the self-calibration button to ensure accurate and reliable data observation.

6. Green power management: This data collector can use two power supply modes: AC220V and DC12V. It also integrates a new generation of green power management module internally to realize intelligent switching between AC and DC power supply.

4. Technical specifications of Dust monitor for photovoltaic power station