Inverters are an essential part of any solar power system. They convert the direct current (DC) generated by solar panels into alternating current (AC) that can be used in homes and businesses. One of the common problems faced by inverter users is that the output power cannot reach the rated power.
Before that, we need to understand that the output power of a solar photovoltaic system is generally difficult to reach the nominal power of the module, because the power of the module is tested under very good weather conditions, and the temperature of the module is relatively low. Normal weather cannot meet this condition, and the photovoltaic modules cannot receive all the solar energy because the photovoltaic system has losses. For example, in a general large-scale power station, the maximum output power of the system may only be about 85%-90% of the rated power of the components. In small distributed power plants, the maximum output of the system may only be about 90% to 95% of the rated power of the components.
In this blog, we will explore some of the reasons why an inverter may not output as much power as it is rated for.
1. Solar panels that are too large or too small. The size of the solar panels used must match the capacity of the inverter. If the solar panels are oversized or undersized, the inverter may not be able to convert all of the DC power to AC. In the case of oversized solar panels, the inverter may shut down to prevent itself from being overloaded. With solar panels that are undersized, the inverter may not be able to convert all of the DC power to AC power, resulting in lower output power.
2. The inverter does not operate within the specified temperature range. If the temperature is above or below this specific temperature range (check the manual for specific temperatures), the inverter may not be able to operate at its rated capacity. In colder temperatures, the efficiency of the inverter may decrease, resulting in lower output power. At higher temperatures, the inverter may shut down to protect itself from damage.
3. Wiring and connection problems The wiring and connection between solar panels and inverters must be properly installed and maintained. If there is a problem with the wiring or connection, the output power may be reduced. This can be caused by loose or corroded connections, damaged wiring, or incorrectly configured wiring.
4. The design of the inverter will also affect its output power. Some inverters may have a lower efficiency rating, which results in lower output power. Due to their design, inverters may also have lower power ratings, which limits the amount of AC power they can produce.
5. Overload. If the inverter is overloaded by a DC source overload, it may shut down to protect itself from damage. This results in lower output power because the inverter cannot convert all the DC power to AC power.
So,how to judge whether the photovoltaic system is normal?
1. Check the output power of the solar inverter. In particularly good weather, if more than 90% of the module power can be achieved, then there is no problem with the design of the system.
2. Simple calculation of power generation. Check the local average daily power generation hours, multiply the hours by 365, and then multiply by the system efficiency, you can get the annual average power generation. Typically, the system efficiency is 0.8. For example, the average number of hours of power generation per day is 3.5, and a 40-kilowatt power plant has an average annual power generation of 40*3.5*365*0.8=40880 degrees. If it is within this range, the system is well designed and installed.