What are the factors that affect the power generation of photovoltaic power plants? The same investment, the same lighting, a little attention to design and installation, the results may be quite different. How to make the system generate more power, let’s talk about five factors that should be paid attention to when increasing photovoltaic power generation. These five aspects can make the power generation effect of the photovoltaic system better!
1. Conversion efficiency of photovoltaic modules
Photovoltaic modules are the core factor affecting power generation. The higher the conversion rate of photovoltaic modules, the better the power generation effect. The mainstream material of components is silicon, and the classical theoretical limit of the conversion rate of silicon is 29%. The record created in the laboratory was 25%. Since the beginning of this century, my country's solar photovoltaic has entered a period of rapid development, and the efficiency of solar cells has been continuously improved. With the help of nanotechnology, the conversion rate of silicon materials in the future can reach 35%, which will become a "revolutionary" in solar power generation technology. sexual breakthrough".
In addition, when installing photovoltaic modules, try to face the angle and direction of the maximum solar radiation. The installation angle is generally the local latitude plus 5 degrees, and the installation aspect angle is generally a little west of the south.
2. Safe and efficient inverter
The wider the inverter voltage range, the higher the power generation. The number of inverters should be as small as possible. The greater the power of the inverter, the higher the efficiency. The cooling air duct of the inverter is to enter the air from the bottom and to discharge the air from the top. The inverter should be installed vertically. It is strictly forbidden to install it horizontally or upside down. . The panel of the inverter should face north to avoid sunlight.
When installed outdoors, install a rainproof and sunscreen on the inverter to avoid direct sunlight and rainwater immersion. The inverter is not directly exposed to the sun or other heat sources. The inverter must be placed in a space with air circulation. The inverter is divided into two types: forced air cooling and natural heat dissipation. The inverter itself is a heat source, and all heat must be dissipated in time. It cannot be placed in a closed space, otherwise the temperature will rise higher and higher.
3. System configuration standardization
The system configuration of some photovoltaic power plants is patchwork. The components may not be bad, but the effect of putting them together is greatly reduced. A perfect standardized system must go through countless matching tests, data comparisons, system debugging, installation and demonstrations, and finally achieve a perfect and stable power generation to form a perfect system. Such a system is called a standardized system. .
4. Reduce loss
For line loss, the DC photovoltaic line should be as short as possible, and the distance between the inverter and the meter should be as short as possible. The line loss of the DC and AC circuits of the system should be controlled within 5%. For this reason, wires with good electrical conductivity should be used in the design, and the wires need to have a sufficient diameter. Construction does not allow cutting corners. During system maintenance, special attention should be paid to whether the connectors and terminals are firm.
Dust loss, the dust loss of the power station may reach 6%! Components need a lot of wiping down.
Combination loss, any series connection will cause current loss due to the current difference of the components; any parallel connection will cause voltage loss due to the voltage difference of the components; the combination loss can reach more than 8%, and the standard of China Engineering Construction Standardization Association is less than 10%
In order to reduce the combination loss, the components with the same current should be strictly selected to be connected in series before the installation of the power station. The attenuation characteristics of the components are as consistent as possible. According to the national standard GB/T--9535, the maximum output power of the solar cell module is tested after the test under the specified conditions, and its attenuation must not exceed 8%. Isolation diodes are sometimes necessary.
5. Daily operation and maintenance
Cultivate the habit of regularly checking the power generation, and then the photovoltaic module is the core part of the photovoltaic power station, which determines the power generation of the photovoltaic power station, mainly including the cleaning frequency of the module, the replacement and maintenance of the module failure, and the treatment and prevention of weeds between the arrays Weed shadows falling onto component surfaces, etc. Real-time monitoring and regular maintenance, just like your own car.
So how to carry out daily operation and maintenance?
Maintenance of components and brackets
1. The surface of photovoltaic modules should be kept clean. Dry or damp soft and clean cloth should be used to wipe photovoltaic modules. It is strictly forbidden to use corrosive solvents or hard objects to wipe photovoltaic modules. Photovoltaic modules should be cleaned when the irradiance is lower than 200W/㎡, and it is not advisable to use liquids with a large temperature difference from the modules to clean the modules.
2. The charged warning sign on the photovoltaic module must not be lost.
3. Photovoltaic modules should be checked regularly. If the following problems are found, the photovoltaic modules should be adjusted or replaced immediately.
Maintenance of Inverter
1. The structure and electrical connection of the inverter should be kept intact, there should be no corrosion, dust accumulation, etc., the heat dissipation environment should be good, and there should be no large vibration and abnormal noise when the inverter is running.
2. The warning signs on the inverter should be intact and undamaged.
3. The cooling fans of the modules, reactors, and transformers in the inverter should start and stop automatically according to the temperature. The cooling fans should not have large vibrations and abnormal noises when they are running. If there is any abnormality, power off and check.
4. Disconnect the circuit breaker on the AC output side (grid side) once regularly, and the inverter should immediately stop feeding power to the grid.
5. If the temperature of the DC bus capacitor in the inverter is too high or exceeds the service life, it should be replaced in time.
Maintenance of combiner box
1. The DC combiner box must not be deformed, corroded, leaked, or dusty. The safety warning signs on the outer surface of the box should be intact and undamaged, and the waterproof lock on the box should be flexible in opening and closing.
2. Each terminal in the DC combiner box should not be loose or corroded.
3. The specifications of the high-voltage DC fuses in the DC combiner box should meet the design requirements.
4. The insulation resistance of the positive pole to the ground and the negative pole to the ground of the DC output busbar should be greater than 2 megohms.
5. The breaking function of the DC circuit breaker equipped at the DC output busbar end should be flexible and reliable.
6. The lightning protector in the DC combiner box should be effective.
Maintenance during extreme weather
1. If the trip occurs in rain, it may be that the terminal is not tight. If this happens, it must be dealt with after the rain has passed. Use insulating tape to wrap the terminal, and then observe whether it is tripped. If the trip continues, It should be reported to the service center or the local power station.
2. In thunderstorm days, the air switch under the meter should be turned off to prevent damage to electrical equipment. After the thunderstorm, close the switch again.
Warm reminder: Don’t underestimate the cleaning and maintenance of household photovoltaic power plants. After cleaning, the power generation of the power plant can increase by 5%-30%. The frequency of cleaning is only ten times a year or once a month.
Cleaning up of pollutants
Generally, the service life of photovoltaic modules is about 25 years. Regularly clean the bird droppings, leaves and other shelters on the module panels to ensure that the panels are exposed to sunlight to the maximum extent. If you usually like cleanliness and have high requirements for power generation effect, you can also clean the components yourself, but you need to pay attention to the following points.
1. Generally choose to clean the components in the morning or late in the afternoon. When cleaning personnel, it is forbidden to stand less than 1 meter away from the edge of the roof for operation.
2. Before cleaning the components, check whether there is any record of abnormal power output in the monitoring records, analyze whether it may cause leakage, and check whether the connecting wires and related components of the components are damaged or adhered. Before cleaning, you need to use a test pen The aluminum frame, bracket, and tempered glass surface of the module are tested. To eliminate hidden dangers of leakage and ensure personal safety.
3. Personnel cleaning components should wear corresponding work clothes and hats to avoid scratches and injuries. Hooks and straps should be prohibited on clothing or tools. Threads and other parts that are prone to tripping.
4. It is strictly forbidden to clean photovoltaic modules under the weather conditions of strong wind, heavy rain, thunderstorm or heavy snow. Winter cleaning should avoid rinsing or rinsing with cold water when the panel is hot.
5. It is strictly forbidden to use hard and sharp tools or corrosive solvents and alkaline organic solvents to wipe photovoltaic modules, and it is forbidden to spray cleaning water to component junction boxes, cable trays, combiner boxes and other equipment.