With the progress of photovoltaic production technology and the support of government policy, photovoltaic power generation in recent years is like "old Wang Xietang Qianyan, flying into ordinary people's homes". More and more families and enterprises begin to install photovoltaic on their roofs. But in the process of photovoltaic power generation, many users find out why the same number of photovoltaic components generate different amounts of electricity in the same period of time? Don't worry, read this dry article to let you know.
First, what causes the difference in power generation?
1. Environmental factors
The lighting conditions (solar energy resources) are different in different areas. In areas with superior solar energy resources, the power generation is naturally high.
Generally speaking, China is rich in solar energy resources, but the solar energy resources in different regions are still very different.
Northwest China, such as Tibet, Qinghai and Gansu, is the most abundant area of solar energy resources in China. Shandong, Henan, southeastern Hebei, southern Shanxi, northern Xinjiang, Jilin, Liaoning, Yunnan, northern Shaanxi, southeastern Gansu, southern Guangdong, southern Fujian, north-central Jiangsu and Northern Anhui are solar energy. There are two types of areas with abundant resources; the middle and lower reaches of the Yangtze River, Fujian, Zhejiang and Guangdong are three types of areas with general solar energy resources; Sichuan and Guizhou are the four areas with the least solar energy resources.
In this way, it is not difficult to understand why the same photovoltaic power generation of Lao Li in Gansu Province is larger than that of Lao Wang in Jiangsu Province.
2. Installation Angle of Photovoltaic Module Array
When assemblies are installed, they should be installed in the direction with the most sunshine (the south is the best), and the installation inclination is generally determined by the latitude of the installation location, which is slightly different in different regions.
3. Quality of Photovoltaic System
The solar energy conversion rate of high-quality photovoltaic products is obviously higher than that of low-quality products. It is very important to select qualified photovoltaic products from regular manufacturers, which is the premise to ensure high power generation of photovoltaic power plants.
4. Choosing a Regular Spectrum-Dependent Photovoltaic Company
To install photovoltaic, we must find a regular and reliable photovoltaic company! Product quality assurance, plus professional design, installation and perfect after-sales operation and maintenance, can ensure that the photovoltaic power plant we invest in can operate steadily for 25 years!
Greed for cheap, good product selection has been assured that making money has been cool! This is the king way to invest in photovoltaic power plants!
2. Sharing Several Ways to Improve the Power Generation of Photovoltaic Power Station
1. Inclination of photovoltaic module installation
The azimuth angle of photovoltaic modules is generally chosen in the south direction to maximize the output per unit capacity of photovoltaic power plants. As long as it is in the South (+20 degrees), it will not have a great impact on power generation. If conditions permit, it should be 20 degrees southwest as far as possible.
2. Efficiency and Quality of Photovoltaic Modules
Calculating formula: theoretical power generation = annual average total solar radiation * total battery area * photoelectric conversion efficiency
There are two factors, cell area and photoelectric conversion efficiency, in which the conversion efficiency has a direct impact on the power generation.
Component Matching Loss
Any series connection will cause current loss due to component current difference, and any parallel connection will cause voltage loss due to component voltage difference. Losses may exceed 8%.
Guarantee good ventilation condition of components
Data show that the high output power of crystalline silicon photovoltaic module group decreases by 0.04% when the temperature rises by 1 C. So we should avoid the influence of temperature on power generation and maintain good ventilation conditions.
The loss of dust should not be neglected
The faceplate of crystalline silicon module is toughened glass. When exposed to the air for a long time, organic matter and a lot of dust will accumulate naturally. Surface falling ash to shield light will reduce the output efficiency of components and directly affect the power generation.
At the same time, it may cause the "hot spot" effect of components, which may lead to component damage.
Rainwater can be cleaned without special maintenance. If you encounter attached dirt, simply wipe it.
3. Reducing Line Loss
In the photovoltaic system, cables account for a small part, but the influence of cables on power generation can not be ignored. It is suggested that the loss of DC and AC circuits should be controlled within 5%.
Cables in the system should be well insulated, heat and flame retardant, moisture and light resistance, type of cable core and size of cable.
4. Inverter efficiency
Photovoltaic inverters are the main components and important components of photovoltaic systems. In order to ensure the normal operation of power plants, the correct configuration and selection of inverters is particularly important. In addition to the configuration of the inverters according to the technical specifications of the whole photovoltaic power generation system and referring to the manufacturer's product sample manual, the following technical specifications should be generally considered:
(1) Rated output power
(2) Adjustment Performance of Output Voltage
(3) Whole machine efficiency
(4) Start-up performance
3. Cleaning Points of Photovoltaic Modules
1. Necessity of cleaning photovoltaic modules
In the operation of photovoltaic power generation system, it is necessary to keep the lighting surface of photovoltaic modules clean. Because dust shielding is the most important factor affecting the power generation capacity of photovoltaic power generation system, its main impacts are:
(1) Shielding the sun's rays and affecting power generation
(2) Affecting the heat dissipation of components, thereby reducing the conversion efficiency of components.
(3) Dust with acidity and alkalinity deposits on the surface of components for a long time, erodes the glass surface of components and causes rough and uneven glass surface, which further accumulates dust, at the same time increases diffuse reflection of sunlight on the glass surface, and reduces the ability of components to receive sunlight.
(4) Dust, leaves, bird droppings accumulated on the surface of components for a long time will cause partial heating of the components'batteries, coke burning of the batteries and backplanes, and even fire. Therefore, components need to be cleaned from time to time.
2. Cleaning methods of photovoltaic modules
The cleaning of photovoltaic modules can be divided into two ways: ordinary cleaning and water cleaning. If dust accumulates on the assembly surface, the dry dust and leaves attached to the assembly surface can be cleaned with a clean line duster or a cloth. For hard foreign bodies, such as clay, bird droppings and viscous objects, a slightly harder plastic or wood scraper can be used to scrape the surface of glass to prevent damage. If dirt cannot be removed, rinse with clean water. Cleaning can be carried out with mops or flexible brushes, such as oil dirt, detergent or soap water, etc. to clean the contaminated area separately. After cleaning, use a clean cloth to dry the water marks. Do not clean with corrosive solvents or wipe with hard materials. At present, component cleaning methods mainly include manual cleaning, sprinkler, intelligent machinery and so on.
3. Precautions for cleaning photovoltaic modules
The cleaning of photovoltaic modules is usually carried out in the morning, evening, night or rainy day. Consider the following reasons:
A. Avoid the possible electric shock injury and damage to components caused by wiping and cleaning components under high temperature and strong light.
B. Prevent the loss of photovoltaic power generation caused by artificial shadows in the cleaning process, and even the hot spot effect.
C. The surface temperature of the components is quite high at noon or in good light to prevent the glass from bursting or damage caused by cold water on the glass surface. At the same time, when cleaning in the morning and evening, it is necessary to choose the time when the sun is dim. Also consider using rainy days for cleaning, because of the help of precipitation, cleaning process is relatively efficient and thorough.
(2) Aluminum frame and photovoltaic bracket of photovoltaic module may have sharp sharp corners. During the cleaning process, attention should be paid to the safety of cleaning personnel. Workwear, hats, insulating gloves and other safety articles should be worn to prevent leakage and bruising. In clothing or tools, hooks, belts, thread heads and other parts that easily lead to tie can not appear.
(3) In the cleaning process, it is forbidden to trample or other ways to use photovoltaic components, guideway brackets, cable bridges and other photovoltaic system equipment.
It is strictly forbidden to clean photovoltaic modules in strong wind, heavy rain, thunderstorm or heavy snow. Cleaning in winter should avoid rinsing, to prevent low temperature and icing, resulting in dirt accumulation: Similarly, do not rinse the panel with cold water when it is very hot.
It is strictly forbidden to wipe photovoltaic modules with hard and sharp tools or corrosive solvents and alkaline organic solvents. It is forbidden to spray cleaning water into assembly junction box, cable bridge, confluence box and other equipment. When cleaning, the water impact pressure of the washing equipment on the components must be controlled within a certain range, so as to avoid the cracking of the components'batteries caused by the excessive impact force.
IV. Inspection and Maintenance of Photovoltaic Modules and Photovoltaic Arrays
1. Periodically check the frame, glass, battery, module surface, backplane, junction box, cable and connector, product nameplate, live warning sign, frame and support structure of photovoltaic module. If any of the following problems are found, they should be repaired or replaced immediately:
(1) The glass of photovoltaic module is loose, cracked and broken.
(2) The photovoltaic module has some problems, such as encapsulation, glue intake, discoloration of batteries, scorching, foaming and obvious color change of backplane, etc.
(3) There are bubbles connected with the edge of the photovoltaic module or any circuit in the photovoltaic module.
(4) The terminals of photovoltaic module can not be well connected because of loose, off-line, corrosion, etc. when the junction box of photovoltaic module falls off, deforms, distorts, cracks or deforms.
_Condensation, water intake and failure of hollow glass curtain wall components affect the visual and thermal performance of photovoltaic curtain wall engineering.
2. The photoelectric parameters, output power and insulation resistance of photovoltaic modules and square arrays should be tested regularly in order to ensure the normal operation of battery components and square arrays.
3. Check regularly whether the anti-corrosion coatings of the metal support and the structural members of the photovoltaic square arrays are exfoliated and rusted, and regularly coat the support with anti-corrosion treatment. The grounding resistance of each point should be no more than 4.
4. The whole structure of photovoltaic array should not be deformed, dislocated and loosened. The main stress components, connecting components and connecting bolts should not be loosened or damaged, and the welds should not crack.
5. The planting bars or post bolts used for fixing the photovoltaic array should not be loosened. The photovoltaic array installed on the base of the prefabricated counterweight block should be placed smoothly and neatly, and its position should not be moved.
6. For the battery square bracket with pole axis automatic tracking system, the mechanical and electrical performance of the tracking system should be checked regularly.
7. Check regularly the growth of plants around the square array to see if the photovoltaic array is blocked. If so, it should be cleaned up in time.
V. Maintenance of Photovoltaic Inverter and Grid-connected Distribution Box
1. Operation, Maintenance and Repair of Inverter
Notes for Inverter Use:
(1) Inverters, as DC-to-DC equipment of power plants, should also ensure reliable connection, and check whether their DC and AC cables are firmly connected. When loosening occurs, contact the installer in time to deal with it.
(2) Inverter will produce some heat when working. Therefore, it is also necessary to ensure that the heat dissipation of the inverters is good, to ensure that the inverters are open around, if there is accumulation of debris, clean up in time.
(3) When the inverters work, they emit heat, especially at noon, where the local temperature is high. Do not touch the inverter, especially the bottom radiator, to prevent scalding.
(4) If the inverter fails to generate electricity, please contact the installer or the inverter manufacturer in time.
Operation of Inverter