Many people who do not understand photovoltaic power plants or do not have a deep understanding have a misunderstanding: when there is plenty of sunshine in summer, the power generation of photovoltaic power plants will be higher. But in fact, if the power generation of distributed photovoltaic power plants is sorted by season, it is spring, autumn, summer, and winter.
Although there is plenty of sunshine in summer, high temperature, high humidity, heavy rainfall, and relatively frequent severe weather in summer will all have a certain impact on the power generation of the power station. The daily power generation of a photovoltaic power station is related to the local sunshine intensity, the orientation and installation inclination of modules, and seasonal weather conditions. The key factors are irradiance and ambient temperature. Hot summer is often accompanied by high temperature, while It is not that the irradiance is high, and the temperature characteristic of the solar module is a negative temperature coefficient, that is, the peak power of the module decreases with the increase of the temperature. Taking Yingli 60cell series modules as an example, as shown in the figure below, under the test conditions of NOCt (irradiance of 800W/m2, ambient temperature of 20°C, and wind speed of 1m/s, the operating temperature of the module in the open circuit state), the cell’s For every 1 degree increase in operating temperature, the peak power will decrease by 0.42%.
Source: Solarbe Sobi Photovoltaic Network
High temperature will not only lower the power generation, but the hot spot effect formed by high temperature will also affect the life of the components. What is called "hot spot effect" means that under certain conditions, the solar cell Modules with significantly worse electrical properties) will be used as loads to consume the energy generated by other solar cell modules that are illuminated. At this time, the temperature of the solar cell module will increase significantly. The hot spot effect is considered to have occurred.
According to statistics, the hot spot effect of photovoltaic power plants will directly shorten the service life of solar modules by 30%, which may cause module failure in the long run. The temperature of the hot spot effect cell will increase with the increase of irradiance, which is why summer is a high fire season for photovoltaic power stations.
The PID effect generated by high temperature can also cause component failure. The PID effect, also known as potential-induced attenuation, is a phenomenon in which ion migration occurs under the action of high voltage between the packaging material of the battery module and its upper and lower surface materials, and the battery sheet and its grounded metal frame, resulting in attenuation of module performance. Improper cooling of photovoltaic power plants in high temperature weather is prone to PID effect, resulting in component failure.
In addition to affecting solar modules, the high temperature environment will also affect the working efficiency of photovoltaic inverters. Because the inverter is usually installed outdoors, even in direct sunlight, the internal temperature of the inverter will rise correspondingly in the high temperature environment in summer. The interior of the inverter is composed of many electronic components, and the electronic components have rated Working temperature, if the ambient temperature is high, the temperature rises quickly when the inverter is running at full power. If the heat dissipation is not good at this time, when the inverter continues to work, the heat of the electronic components will always gather in the cavity, and the temperature is too high. Under certain circumstances, the inverter may stop working, the aging of components will be accelerated, and the life of the machine will be shortened. The high temperature environment may also cause the inverter to be protected by over-temperature and load reduction, which will affect the power generation of the power station.
Although compared with the power generated by the power station every day, the loss is only a "negligible" point, but over time, the power loss will be more. Therefore, "the higher the temperature, the more power generation" is a misunderstanding. The peak power generation of photovoltaic power plants often occurs in late spring and early summer or late summer and early autumn. At this time, the ambient temperature is suitable and the irradiance is high, reaching the peak of photovoltaic power generation. good condition.
