photovoltaic array installation inclination angle is mainly determined by the longitude, latitude, and optimal irradiation amount of the installation area. Due to the limitations of the installation conditions, the angle can be adjusted appropriately when the assembly installation inclination angle cannot reach the optimal level, and the power generation of the non-south-facing roof will be greatly affected.
2. How to determine the orientation of the photovoltaic array? What impact will it have on the power generation system?
Since the main reason affecting photovoltaic power generation is sunshine, the components should be installed in the direction with the most sunshine when installing them. Different installation angles also affect the power generation efficiency of photovoltaic modules. The following figure shows the different efficiencies of photovoltaic modules in a city in southern China. (Note: The power generation efficiency of photovoltaic cells with different orientations is different under different locations and climatic conditions.)
3. How to choose photovoltaic modules?
can choose photovoltaic modules of different types and specifications according to the specific circumstances of the installation site. The effective utilization area at the installation site determines the specifications and sizes of the components. If you want to install a larger capacity per unit area, you can choose high-efficiency modules. Components of different border colors can also be selected according to the appearance of the existing building, and the connector length of the component can be determined according to the serial and parallel wiring method of the site. The selection of
components requires comprehensive consideration of the installation area, installation capacity, cost and other factors. Generally speaking, you should choose component products with good reputation, good quality, certified (including fire protection grade), and good after-sales service.
4. For household distributed photovoltaic systems, how to choose photovoltaic inverter ? If the installation site of photovoltaic grid-connected inverter was not considered in the early stage of the design, how should we choose a photovoltaic inverter?
photovoltaic inverters generally choose outdoor type, adopt natural cooling method, high shell protection level (usually IP65), very few environmental modifications required for installation, and low cost; at the same time, since inverter is installed outdoors, the impact of the noise generated by the inverter operation on the user will be greatly reduced, but good equipment protection is required.
generally configures the inverter of the corresponding power segment according to the system requirements. 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 similar to the total input power (usually over-configuration is controlled within 1.3), which can save costs.
On the other hand, the selection of inverter capacity can be optimized according to installation conditions. If the installation site is not clear at the beginning of the design, it is not fully considered that the installation site should be selected as low-power photovoltaic inverters as much as possible to realize multiple independent power tracking. If necessary, select micro inverter to achieve maximum power tracking of smaller units, so as to ensure series and parallel mismatch caused by insufficient site size or insufficient rules in the later stage.
5.Photoscopic system inverter installation precautions
inverter, as the core component of the photovoltaic system, directly affects the power generation of the system. The following points should be paid attention to:
(1) Because the inverter connection with the power grid has changed the inverter impedance characteristics, it is easy to cause the inverter itself resonance , which often occurs in multiple inverters in parallel;
(2) After the inverter is installed, it is necessary to have a special person to recheck it. And mark and record;
(3) The connection between the inverter ventilation duct and the outer air duct should be softly connected to prevent mechanical noise from being caused by mechanical vibration;
(4) When the inverter noise increases and there is a odor, attention should be paid, check the internal fault of the inverter, and find out the cause and deal with it as appropriate;
(5) Pay attention to the detection of inverter leakage, grounding, phase sequence, etc. during installation and debugging;
(6) At least 2 people are present at the same time during inverter debugging, pay attention to the safety protection of the operators.
6. What is MPPT for photovoltaic inverter? In a household distributed photovoltaic system, when the type, installation orientation and installation inclination of the photovoltaic array are different or some components are blocked, which inverter can be chosen to enable users to obtain the maximum power generation income? The output voltage and current of the photovoltaic square array will change with changes in solar irradiance and ambient temperature, etc., and track and control the changes in the output voltage and current generated by the above reasons, so that the array can be kept in the automatic adjustment behavior of the maximum power output, that is, maximum power point tracking, that is, MPPT (Maximum Power Point Tracking).
In household distributed photovoltaic systems, due to roof limitations, when the type, installation orientation and installation inclination of the photovoltaic array are different, or some components are blocked during certain time periods, it is advisable to use a photovoltaic inverter with multiple independent MPPT control functions, which can more flexibly configure the system, reduce potential system efficiency and power generation losses, improve power generation efficiency, and obtain the maximum power generation benefits for users.
7. For household distributed photovoltaic systems combined with buildings, how to consider the color, light transmission, size and shape of photovoltaic modules? In terms of color, you can try to choose one that is consistent or similar to the architectural color. For light transmission, the building's requirements for light should be considered, which not only meets the indoor light needs and avoids secondary lighting, but also makes full use of the building space and area, reasonably selects sizes and shapes, balances and optimizations, and professional technical designs.
8. Precautions for installing photovoltaic components on color steel plate roof
Installing photovoltaic components on color steel plate roof requires the following issues:
(1) Installing photovoltaic systems on color steel plate roofs must comprehensively consider whether the life of color steel plate can meet the life requirements of the photovoltaic system;
( 2) Survey and evaluate the corrosion conditions and waterproof system integrity of roofs that have a certain service life, and reinforce or completely repair the structures with hidden dangers;
(3) The photovoltaic module is directly laid out with color steel plates, and it is necessary to consider the ventilation and heat dissipation of the photovoltaic module to reduce the impact of the color steel plate roof temperature on the power generation efficiency of the photovoltaic module and related devices and materials;
(4) The damage to the color steel plate should be avoided during the installation process of photovoltaic modules. Once the water leakage occurs, the water seepage position is transferred due to the absorption of the color steel plate interlayer rock wool (other fillers), and it is difficult to judge the water leakage position;
(5) The mechanical strength of the color steel plate is weak, and the damage to the color steel plate is reduced during the installation of the photovoltaic system, and the mechanical deformation of the color steel plate will affect the structural stability of the photovoltaic system;
(6) When the component is installed at a small angle, dust accumulation at the edge of the component should be dealt with in time after the rain to avoid the accumulation of dust and cause heat spots;
(7) Before installation, a convenient plan for replacement of the color steel plate roof after the expiration of its life.
9. How to determine the installed capacity of a user-used distributed photovoltaic system? The size of the installed capacity of the distributed photovoltaic system for households depends on the load of the power equipment, the style of the roof and the roof area, and the final installation capacity is determined in combination with the approval of the power grid company. Generally, the installation volume of flat roofs is about 100~300 watts/square meter.
10. How to estimate the power generation of a user-used distributed photovoltaic system?
To estimate the power generation of the photovoltaic power generation system, you need to know the number of peak sunlight hours in the system installation (the total solar radiation received on the photovoltaic module surface is converted into the number of hours at irradiance of 1000W/m2), system efficiency, and system installation capacity.
For example, a 10kW photovoltaic grid-connected system is installed in Beijing, with a peak sunlight hours of 4 hours, and the efficiency of the photovoltaic grid-connected system is about 80%. Therefore, the daily power generation calculation formula for the system = component installation capacity × peak sunlight hours × system efficiency = 10×4×0.8=32kWh, which is about 32 kWh.
11. After the user-use distributed photovoltaic system is connected to the grid, how to distinguish whether the electricity currently used at home comes from the power grid or the solar cell components of your own home?
After the installation of the household distributed photovoltaic system is completed, the power grid company will conduct grid-connected inspection and acceptance. After the acceptance is passed, two electricity meters (or two-way electricity meters, as described later) will be installed at the owner's home. The two electricity meters will independently measure the power generation of the photovoltaic system and the electricity consumption of the mains. The easiest way is to look at the electricity meter. As long as the electricity meter at the photovoltaic system is used to generate electricity from the photovoltaic cell modules.
12. If it is continuously rainy or smog after installation, will the photovoltaic power generation system still work? Will there be insufficient power or power outage?
photovoltaic cell modules can also generate electricity in a certain low light, but due to continuous rainy or haze weather, the solar radiation is low. If the working voltage of the photovoltaic system does not reach the start voltage of the inverter, the system will not work. The distributed photovoltaic system for households operates in parallel with the distribution network. When the distributed photovoltaic system for households cannot meet the load needs or does not work due to cloudy days, the power of the power grid will be automatically replenished, and there is no problem of insufficient power or power outage.
13. Will there be insufficient electricity when it is cold in winter? The power generation of the
photovoltaic system is indeed affected by temperature, and the direct influencing factors are the irradiation intensity and sunshine duration and the working temperature of the solar cell components. In winter, the irradiation intensity will inevitably be weak, the sunshine will be short, and the power generation will generally be less than in summer, which is also a very normal phenomenon. However, since the household distributed photovoltaic system is connected to the power grid, as long as the power grid has electricity, the household load will not be short of power or power outage.
14. Can electricity generated by household distributed photovoltaic systems during the day be stored for night lighting?
can store the electricity generated by the distributed photovoltaic system in the daytime for night lighting, which requires the addition of electrical components such as controllers and batteries. During the day, the controller stores the power generated by the photovoltaic in the battery, and at night, the controller releases the power stored by the battery for lighting. In the absence of energy storage equipment, if the power grid is powered off, the system will stop working, but if the grid-connected inverter is replaced with an intelligent microgrid inverter (a hybrid grid-connected and off-grid inverter), the system will still operate normally.
Source: Internet
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