Why is summer not the season with the highest power generation of photovoltaic power plants?
Let's look at a picture:
Summer that you think enjoys the long sunshine time and strong solar power is not the period of the highest photovoltaic power generation in a year, or even some "bottom", Why?
The weather is getting hotter, do you realize that you are in a period of the highest power generation of photovoltaic modules in a year and are about to enter the downhill, or continue to look forward to the next generation of photovoltaic power generation?
Knock on the blackboard: Summer is not the season with the highest photovoltaic power generation!
High temperature causes component power attenuation
Test PV learned that when the photovoltaic module is working normally, the standard operating temperature of the cell is 25°C. Under the operating conditions greater than 25°C, each time the temperature rises, the output power of the module will cause a corresponding attenuation. At this time, the power generation of the photovoltaic module is affected by the temperature coefficient of the photovoltaic module.
Normally, the output power of the N-type single crystal component is reduced by 0.38% of the reference value for every increase of 1 ℃ in the cell temperature, and the output power of the P-type component is reduced by 0.42% of the reference value.
The researchers conducted relevant experiments on the influence of temperature on power generation performance. The data shows that when the temperature changes from -3.15 to 66.85 ℃, the conversion efficiency temperature change rate of single-crystal silicon solar cells and amorphous silicon solar cells is -0.176%/ ℃ and -0.08%/℃.
Summary of temperature characteristics of different types of solar cells
Previously, a photovoltaic worker tested the indicated temperature of the photovoltaic module when the outside temperature was as high as 40°C in July, up to 57.5°C, and the temperature of the backplane reached 63°C! From this, the attenuation caused by the high temperature in summer is up to about 15%!
Component hot spots cannot be ignored
Also worth preventing is that the local temperature caused by the hot spots of the components is too high, which can affect the life of the battery and even cause a fire.
When referring to the hot spot of the module, it cannot be ignored that the blocking of incident light along the mud zone under the module makes the current in this area significantly smaller than that in other non-mud zone areas. The hot spot effect in the dust deposit area is an important factor causing the reduction of photovoltaic module power generation.
Focus on operation and maintenance to increase power generation
How to maintain power generation during the high temperature period in summer has become a top priority for photovoltaic power plants, and it is rainy in summer.
The roof projects of industrial plants are mostly around one megawatt, and the annual power generation is one million kWh. Generally, the accumulation of dust on the surface of the module will cause a loss of 10% or more of power generation, but the effect of floating ash is not so large. Many operation and maintenance data reflect that the benefit of cleaning on module power generation is about 3-5%. Therefore, the biggest culprit for the loss of power generation of modules is mud belts-mud belts that are difficult to remove and will affect the power generation of the entire module.
Test PV previously reported the removal of mud belt operation and maintenance tool-drainage desilter does not require human participation or energy consumption, only the well-known "capillary phenomenon" principle can be used to solve the long-term problem of dust and mud bands on the border in the industry.
Fog water is discharged near the drain desilter to reduce dust accumulation