1. What are the parts of distributed photovoltaic grid-connected power generation system?
The distributed photovoltaic power generation system consists of photovoltaic modules, photovoltaic grid-connected inverters, two-way metering meters and related spare parts.
2. How to obtain local solar resource data?
For photovoltaic system design, the first step is also a crucial step. It is to analyze the solar energy resources and related meteorological data at the place where the project is installed and used. Meteorological data such as local solar radiation, precipitation, and wind speed are key data for the design system. At present, the weather data for any location in the world can be searched for free for NASA NASA Meteorological Database.
3. How to choose the grid-connected voltage of the distributed photovoltaic grid-connected system?
The grid-connected voltage of the distributed photovoltaic system is mainly determined by the installed capacity of the system. The specific grid-connected voltage must be determined in accordance with the access system of the grid company. The AC220V is usually used to connect to the grid, and commercial AC380V or 10kV can be used to connect to the grid.
4. What is the inclination of the PV array installation?
The tilt angle of the PV array installation is generally determined by the latitude of the installation site. There is a slight difference in each region. In our province, it is generally 26 degrees plus or minus two degrees.
5. How to determine the installation orientation of the PV array? What is the impact on the power generation effect?
As the primary cause of photovoltaic power generation is the amount of sunlight, the components should be installed in the direction with the best sunlight. Different installation angles will also affect the power generation of photovoltaic modules. Our province is generally plus or minus 3 degrees positive.
6. How to choose PV modules?
According to the specific conditions of the installation site, different types of PV modules can be selected. The effective use area of ​​the installation site determines the size of the module. If you want to install a larger capacity within the unit area, you can use high-efficiency modules. You can also choose according to the appearance of existing buildings. Components with different borders, according to the site of the serial connection and connection line to fix the length of the connector, the selection of components need to consider the installation area, installed capacity, cost and other factors, in general, should use good reputation, good quality, certification, Quality assurance after-sales service, with fire certified component products.
7, how to choose inverter?
Generally, according to the requirements of the system, an inverter corresponding to the power segment is configured. The power of the selected inverter should match the maximum power of the photovoltaic cell array. Generally, the rated output power of the photovoltaic inverter is approximately the same as the input total power. Can save costs.
8. How to consider the color, light transmission, size and shape of PV modules for distributed photovoltaic power generation projects combined with buildings?
Color can be chosen as close as possible to the color of the building. For light transmission, it is necessary to consider the full use of the building space and area, reasonably select the size and shape, balance and optimize, and professional technical design.
9. Does the design and installation of PV arrays have to take into account the impact of wind speed? How should the construction load and wind resistance requirements be considered when installing distributed PV?
When installing photovoltaic arrays on the roof of a building, the load on the roof of the building must be taken into account, and the turbulence and speed changes that occur after the airflow is encountered should be taken into consideration for the safety of the PV array. Only local wind conditions and landforms must be taken into consideration. The terrain and the relative location of the buildings where PV arrays are planned to be installed in the surrounding environment can ensure the safety of the PV arrays and surrounding life assets.
10. How to determine the installed capacity of domestic photovoltaic power generation system?
The installed capacity of domestic photovoltaic power generation system depends on the load of electric equipment, the style of the roof and the area of ​​the roof, combined with the approval opinion of the power grid company to determine the optimal installation capacity. Under normal circumstances, the installed capacity of the flat roof is approximately 70 watts. Per square meter.
11. How to estimate the generation of distributed photovoltaic grid-connected systems?
To estimate the amount of electricity generated by the photovoltaic system, it is necessary to know the local effective sunshine hours, system efficiency, and system installation capacity. You can also consult your PV system installer for more accurate power generation.
12. After the distributed photovoltaic power generation system is connected to the grid, how do you distinguish between the current electricity used in the home or the solar battery components in your home?
After the distributed power generation system is installed, the power grid company will carry out the inspection and acceptance of the grid connection. After the acceptance, it will install two (or two-way electricity meters) at the owner's home. The two meters will respectively use the photovoltaic system to generate electricity and electricity. Electricity is measured independently.
Since the "all-on-line" model subsidy standard is higher than the "self-use, excess Internet access" model, it is recommended to adopt the "all Internet access mode" access method.
13. Will the photovoltaic power generation system work if there is continuous rain or haze after installation? Will there be power shortage or power failure?
Photovoltaic modules can generate electricity under low-light conditions. However, due to continuous rain or haze, the sunlight irradiance is low. If the PV system's operating voltage fails to reach the inverter's startup voltage, the system will not Work, grid-connected power generation system and distribution network are operated in parallel. When the photovoltaic system can not meet the load demand but not work, the electricity of the power grid will be automatically added. There is no problem of power shortage and power failure.
14, when the cold weather in winter will not be enough power?
Photovoltaic system power generation is indeed affected. Factors that directly affect power generation are radiation intensity and duration of sunlight and working temperature of solar modules. Inevitably, winter radiation intensity will be weak, and the duration of sunshine will be short, and the general power generation will be less than in summer. This is also a normal phenomenon. Distributed photovoltaic power generation is connected to the power grid. As long as the power grid has power, there will be no power shortage or power failure.
15. Will distributed photovoltaic access affect power quality?
Power quality is the quality of power in the power system. The main AC/DC conversion components of the system are inverters. The inverter is put into production after passing the test of the power quality tester, so it will not affect the power quality.
16. Can I store the electricity generated by daytime distributed PV systems for night lighting?
The electricity generated by the daytime distributed generation system can be stored for use as night lighting. This requires the addition of controllers and batteries and other electrical components. The daytime controller stores the electricity generated by the photovoltaics in the battery and the controller at the night stores the battery. The electricity is released for lighting use. In the absence of energy storage equipment, if the grid power-off system will stop working, but if the grid-connected inverter is replaced by an intelligent micro-grid inverter (mixed and off-grid) Inverter), the system can still operate normally.
17. Does the installation of photovoltaic power generation systems in existing buildings require additional cabling? How do you connect to existing electrical systems in your home?
The line of the photovoltaic system is divided into the DC part and the AC part. The two parts of the line need to be separately wired. The AC part should be connected to the grid, and the network point should be located on the user side meter position, and finally be connected to the existing electrical system in the user's home.
18. Where are the monitoring devices of the distributed photovoltaic grid-connected system installed? Will they occupy valuable indoor space?
The monitoring devices of distributed photovoltaic grid-connected systems are divided into large-scale photovoltaic power plant monitoring, off-grid photovoltaic roof system monitoring and household rooftop photovoltaic system monitoring. Photovoltaic monitoring system can be installed outdoors, does not take up indoor space, it can achieve data collection of various links in the photovoltaic system with a variety of hardware products and accessories, data transmission to the remote service platform for relevant data storage and analysis, and finally The report graphs and other forms of feedback to the user system operation.
19. What information does the design engineer need to provide when designing the system according to customer requirements?
The information required by the customer during the system design is divided into options and strong options. The required parts include the installation location of the project, the surrounding environment of the building, the building construction year, the roof type, the roof load, the access voltage level and the roof photo, etc. Some of them include the average monthly electricity consumption, roof plate structure, CAD drawings, roof surface conditions, meter box photos, etc. Of course, the more detailed the optional part, the more detailed it will help to optimize the design more rationally and improve the power generation. .
20, after the system is built, what unit will be accepted?
At the time of acceptance, it was mainly organized by the power grid companies, focusing on grid-connected electrical performance, construction quality, component certification, inverter certification and technical parameters, lightning protection grounding, fire safety, and component fire protection certification.
21, how to install the process?
The installation process of distributed photovoltaic grid-connected power generation system is: basic construction, installation of brackets, installation of components, installation of convergence boxes, inverters, power distribution cabinets and other electrical equipment, installation of connection lines, power grid access systems, and Metering device installation.
22. What electrical safety requirements should be paid attention to in the installation process? Will electrical leakage lead to danger to the human body?
As long as there is sunlight, PV modules will have electricity, so when there is sunlight, it is impossible to cut off the power supply, and because of the series voltage and accumulation, the corresponding voltage to ground will also be very high. Therefore, the system supplier must be strictly observed during the installation process. The installation and operation instructions are to be completed by professional installation personnel. The wiring part of the equipment is to be installed using professional connectors. The protection level is set to IP65. The electrical equipment is also protected by air switches.
23. How to meet the requirements of heat insulation and sound insulation in buildings when combined with distributed photovoltaics? Will this affect indoor lighting?
Different glass materials and structures are used to control heat insulation and sound insulation. The indoor system noise of distributed system equipment is determined by the user and the manufacturer's agreement to meet the needs of a wide range of users. Sound insulation and heat insulation layers combined with buildings can be designed to meet different requirements. User personalized needs.
Different solar cells and arrangements are used to adjust the light transmittance. When distributed and buildings are combined, the lighting area will be left without affecting the indoor lighting.
24. How to prevent lightning with photovoltaic power generation combined with buildings?
Lightning is mainly divided into two kinds of hazards, direct lightning strike and indirect lightning strike.
Direct thunder protection: Set up metal lightning protection ground wires on tall buildings to release huge thunderstorm clouds.
Inductive lightning protection: In the photovoltaic system, adding lightning arrester, that is, in the convergence box, inverter and other electrical equipment installed lightning protection module to protect against indirect lightning.
25. What is a bi-directional meter and why do I need a bi-directional meter?
A bidirectional energy meter is a meter that can measure electricity and electricity. Both power and electricity are directional. From the perspective of electricity consumption, electricity consumption is counted as positive or positive electricity, and electricity generation is counted as negative or negative electricity. Electric energy, the meter can read out the forward and reverse electricity respectively through the display screen and store the electricity data.
The reason for installing bi-directional meters is that the electricity generated by photovoltaics cannot be fully consumed by users. The remaining electricity needs to be delivered to the grid. Meters need to measure a figure. When photovoltaic generation cannot meet user requirements, this requires measurement. One figure, a normal single-block meter cannot meet this requirement, so it is necessary to use a smart meter with a bidirectional metering function.
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