Does different weather affect the power generation of photovoltaic modules?

· PV Industry News

Here are a few questions and answers we have compiled about the weather

As far as weather conditions are concerned, the key factors affecting power generation are light conditions and the operating temperature of PV modules.
Those weather conditions with poor lighting conditions will result in a reduction in the power generation of the system. Common are: continuous rain and haze.
In addition, if the temperature is not within the operating temperature range of the photovoltaic modules, the power generation of the system will also be reduced. Common are: hot days and extremely cold weather. Photovoltaic modules have a normal working temperature range, and within this temperature range, the solar energy conversion rate of the modules is the best. If the air temperature is not within this temperature range, the component's self-protection system will activate, resulting in reduced power generation efficiency.

Does it affect the power generation if it rains or is cloudy?

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Photovoltaic cell modules can also generate electricity in a certain low light, but the power generation will be reduced because the light time is reduced and the light intensity is relatively weakened. But the annual average power generation we calculated (such as 1100 kWh/kw/year) can be achieved. If it is continuous rainy or foggy weather, the solar radiation illuminance is low, and if the working voltage of the photovoltaic system cannot reach the starting voltage of the inverter, the system will not work. Especially for flat roofs, when the rainfall is too heavy, the solar panels may be soaked by the rain because the brackets of the flat roof are installed relatively low. In order to prevent excessive water accumulation on the flat roof and form small ponds, a set of drainage systems can be added before the rainstorm to effectively drain the water. As long as the accumulation of water is not too deep, the impact on the battery panel will be small.

How to deal with problems such as lightning strikes, hail, and leakage of electricity in household photovoltaics?

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First of all, DC combiner boxes, inverters and other equipment lines have lightning protection and overload protection functions. When abnormal voltage such as lightning strike and leakage occurs, it will be automatically turned off and disconnected, so there is no safety problem. In addition, all metal frames and brackets on the roof are grounded to ensure safety in thunderstorms. Secondly, the surface of our photovoltaic modules is made of super impact-resistant tempered glass, which has undergone rigorous testing (high temperature and high humidity) when passing the EU certification. Moreover, good grounding is an important basis for the success of lightning protection measures. Generally, installers will consider the problem of lightning protection and make a lightning protection grounding system during the installation of the power station.

Is PV module installation inefficient when it is cold or hot?

Photovoltaic modules extract energy from light rather than heat. So the cold weather has nothing to do with the amount of photovoltaic power generation. In areas prone to freezing temperatures, energy is generated whenever sunlight hits the components. In fact, colder temperatures may make PV modules perform even better. Due to the temperature coefficient, as PV modules get hotter, higher temperatures can cause module power degradation. TestPV has learned that the standard operating temperature of the cell is 25°C when the photovoltaic module is working normally. Under the working condition of more than 25°C, the output power of the module will be attenuated correspondingly for each degree of temperature increase. At this time, the power generation of the photovoltaic module is affected by the temperature coefficient of the photovoltaic module. Under normal circumstances, for every 1°C increase in cell temperature, the output power of N-type monocrystalline modules decreases by 0.38% of the reference value, and the output power of P-type modules decreases by 0.42% of the reference value.

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Does snow cover in winter affect power generation? Will the power run out?

PV modules and snow can coexist, and the power generation of PV modules when covered with snow depends on the quality and installation of PV modules. Photovoltaic modules undergo thermal cycle testing during production to cope with extreme temperature changes in high temperature and cold climates. In TC testing, modules are subjected to extreme temperature changes. The PV modules tested were placed in an environmental chamber, cooled to -40°C, held, then heated to 85°C, and held again. The components were also subjected to the maximum power current when the temperature increased, and this process was cycled 200 times.

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When PV modules are installed correctly, they will melt faster than ordinary roofs. In addition, if in a very snowy area, the installation design of the photovoltaic carport can be selected.
In winter, the radiation intensity will inevitably be weak, the sunshine duration will be short, and the general power generation will be less than that in summer, which is also a normal phenomenon. However, since the distributed photovoltaic system is connected to the grid, as long as there is electricity in the grid, there will be no shortage of power and power outages for household loads.

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Can the photovoltaic power generation system resist the hazard of hail?

If you live in the northern part of the country, or anywhere with extreme weather conditions, you might imagine PV modules being smashed by a high-speed ice ball. However these are also tested. Qualified components in the photovoltaic grid-connected system must pass strict tests such as the maximum static load (wind load, snow load) of 5400pa on the front, the maximum static load (wind load) of 2400pa on the back, and the impact of hail with a diameter of 25mm at a speed of 23m/s. Therefore, hail will not harm the photovoltaic power generation system. Unless it encounters extreme hail weather, the hail particles as large as eggs hit the photovoltaic panels, and the photovoltaic power station is likely to suffer.

Does the typhoon have any effect on the photovoltaic modules?

When the module is outdoors, it must not only withstand wind load, snow load, static pressure on the surface of the module (such as module stacking, stepping on, etc.), and ice load. IEC61215 also represents the wind load test with the experimental method of mechanical load. According to the definition of IEC61215: For a gust safety factor of 2400Pa, it corresponds to a wind speed of 130km/h (or 36.1m/s). According to the typhoon level, that is to say, the module products should be able to withstand typhoons above level 12.

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Choosing scientific design, high-quality components and brackets, and solar photovoltaic panels that meet specifications are important factors for home photovoltaic power plants to withstand extreme weather. If the power generation decreases or other abnormal conditions occur after extreme weather, you should contact the after-sales personnel in time for system inspection and replacement.