Solar PV Power System FAQ: 40 Questions You Must Know
Profit by the global support and promotion of the photovoltaic industry, home photovoltaic users are increasing, users around the photovoltaic problems also followed more up.
Following is a summary of common questions and answers to PV system, hope more people understand PV, with the right way to love it, to ensure that the system can be healthy and safe for each family to save electricity expenses.
1.How do I choose qualified system parts and how long is the warranty for them?
A: It is recommended to choose system parts certified by national certification bodies, and the key components and raw material models, specifications and manufacturers should be consistent with the certified products. In addition, the specifications and technical parameters of all system accessories should match the design scheme of the whole system. Generally , the moudles require at least 25 years warranty and the inverter requires at least 5 years warranty.
2.Can add wire fencing to the PV array to prevent impact？
A: It is not recommended to install wire mesh. It is not recommended to install wire fences on PV arrays because they may cause shadows on the modules, forming a hot spot effect and affecting the power generation efficiency of the whole PV system.
In addition, since qualified PV modules have passed the impact test, it is generally not necessary to install wire mesh.
3.Can the system’s power generation be monitored online ?
A: If the PV system is installed with corresponding monitoring system, the power generation can be monitored online, and the monitoring system can also monitor key equipment parameters, power quality, environmental parameters, etc. online.
4.Is the power generation monitoring data of the distributed PV grid-connected system the same as the metering data of the electricity meter? How big is the error?
A: The power generation monitoring data of a distributed PV grid-connected system and the metering data of an electric meter are not necessarily the same. If the same metering equipment is used in the same grid-connected network with the same accuracy, then the resulting data is the same. The monitoring equipment used in PV grid-connected systems is often the equipment used by the system construction units themselves, so the equipment is different and the data obtained will be different. How much error there is depends on the specific situation. And the settlement of electricity bills and subsidy costs is based on the metering equipment installed by the power department.
5.How to judge the stability of distributed PV grid-connected system, whether the power quality meets the requirements, and whether the system failure will cause damage to household appliances?
A: You can use the power quality analyzer to test at the grid connection point of the power station to determine whether it meets the national standard. In general, there is a protection device to cut off the power in case of PV system failure, so it will not cause damage to household appliances.
6.If there is a power grid outage or other malfunction, can the household distributed PV grid-connected system still operate ?
A: After a power grid outage, a residential distributed PV system will quit operation and cannot generate electricity. In some extreme cases, there will be an islanding phenomenon, after the grid blackout, the system still continues to run with part of the load, affecting the personal safety of maintenance personnel, and there is the possibility of damage to household appliances and grid facilities. Therefore, distributed photovoltaic systems must have anti-islanding function.
7.Does poor power quality of the grid have an impact on the PV system?
A: Grid quality problems such as high grid voltage and abnormal frequency will cause the inverter to go down, and the system will automatically recover when the grid is restored.
8.What else do I need to pay after installing the PV power system?
- If you apply for financial services when you install the PV power system, you also need to pay the bank loan.
- if your power generation system generation is not enough for your own use, you also need to pay the normal electricity bill.
- Cost of post-maintenance.
9.How about the stability of the photovoltaic power generation system, will it not work after a few years?
A:It is recommended to choose modules that have passed authoritative monitoring and certification around the world, passed salt spray and ammonia corrosion resistance tests, and have excellent power generation performance in low light environments. The power generation performance of the modules can still be maintained at more than 80% after 25 years of use.WinSeven SOLAR has been certified by TUV,CE,CEC,J-PEC,INMETRO,RETIE and is one of the choices for quality components.
10.What are the requirements of the surrounding environment for the installation of rooftop solar photovoltaic system?
A: Rooftop solar PV systems surrounded by large dust, sand, and smoke will affect the light and will lead to a decrease in power generation.
Learn more:Can every family install a solar PV system?
11.Are the benefits of installing on commercial and industrial roofs the same as on individual home roofs?
A: Revenue is different. For distributed photovoltaic power generation, both national and local subsidies are currently fixed, and the revenue is affected by the level of household tariff, which requires developers to judge and decide whether the project is cost-effective according to local subsidies.
12.For PV building integration projects(BIPV), how to consider the color, light transmission, size and shape of PV modules?
A: In terms of color, we can try to choose the same or similar color as the building, for light transmission, we should consider the requirements of the building for light, to meet the indoor demand for light and avoid secondary lighting, but also to make full use of the building space and area, reasonable choice of size and shape, good balance and optimization, as well as professional technical design.
13.Need to install a PV system on an existing building with separate wiring? How do connect it to the electrical system?
A: The wiring of PV system is divided into DC part and AC part, and these two parts of the wiring need to be wired separately. The AC part should be connected to the grid, and the network is located at the customer’s side of the meter, and finally form a connection with the customer’s existing electrical system.
14.How to protect BIPV project from lightning?
A: Lightning is divided into two main hazards: direct lightning strikes and indirect lightning strikes.
- Direct lightning: set up metal lightning conductors on tall buildings, which can release the huge thunderstorm cloud charge.
- Induction lightning: add lightning protectors to the PV system, that is, add lightning protection modules to electrical equipment such as sink boxes and inverters to protect against indirect lightning strikes.
15.Need to disconnect solar PV system during a thunderstorm?
A: Distributed photovoltaic power generation systems are equipped with lightning protection devices, so there is no need to disconnect. It is recommended that for safety, you can choose to disconnect the circuit breaker of the sink box to cut off the circuit connection with the PV module to avoid the harm caused by direct lightning. Operation and maintenance personnel should promptly test the performance of the lightning protection module to avoid the failure of the lightning protection module.
16.What should be paid attention to the fire prevention and firefighting of the household distributed photovoltaic power generation system?
A: It is forbidden to stack flammable and explosive items near the distributed power generation system, which will cause incalculable damage to people and property in case of fire. In addition to the basic fire safety inspection, the PV system is especially required to have the function of self detection and recognition of electric arc and fire to reduce the possibility of fire.
17.Will there be insufficient power when the temperature is low?
A: The power generation of PV system will be affected by the temperature, but the effect is very small. The factors that directly affect the power generation are the irradiation intensity and sunshine as well as the working temperature of solar cell module. In winter, the temperature is lower and the sunshine duration is shorter, so the general power generation is less than in summer, which is also normal.
18.Can the power generated by the distributed photovoltaic power generation system be stored and used at night?
A: This requires the addition of a controller and a battery. The controller will store the power generated by PV in the battery during the day, and the controller will release the power stored in the battery for use at night. In the absence of energy storage equipment, if the grid power failure, the system will stop working, but if the grid-connected inverter is replaced by a network hybrid inverter, the system can still operate normally.
19.Does the PV module have restrictions on the installation location?
A: The extreme working temperature range of PV modules is -40℃ to 85℃, and it is recommended to install them in the temperature range of -20℃ to 50℃, which is the monthly average minimum and maximum temperature of the installation site, and there is no requirement for the altitude of the module installation, but the altitude limit of other supporting electrical equipment should be considered.
20.What are the electrical safety requirements to be noted during installation? Will the leakage of electricity to personal danger?
A: As long as there is sunlight, the PV module will have electricity, so it is impossible to cut off the power when there is sunlight, and the corresponding voltage to ground will be very high due to the accumulation of series voltage. Therefore, the installation process should strictly comply with the installation instructions provided by the system supplier and be completed by professional installers.
a. When installing components, please use insulated tools and do not wear metal accessories.
b. Do not disconnect the electrical connection with a load.
c、Must keep the connector plug dry and clean, do not insert other metal objects into the connector plug, or any other way to make electrical connections.
d. Do not touch or operate PV modules with broken glass, detached bezels and damaged backsheets unless the module is disconnected electrically and you are wearing personal protective equipment.
e. If the module is wet, do not touch the module except when cleaning the module, but follow the module cleaning manual. Always do not touch wet plugs without wearing personal protective equipment or rubber gloves.
21.What is the warranty of the modules?
A: Conventional crystalline modules are covered by a 12-year limited product quality warranty, in addition to a 25-year peak power limited warranty, which guarantees that the peak power degradation of the module will be within a certain range.
22.What are the characteristics of module failure?
A: The common failure phenomena of crystalline silicon modules include cell shattering, hot spot, EVA yellowing, cracked backsheet, snail pattern and other problems visible to the naked eye, while hot spot, junction box deficiency welding, diode failure, electrothermal induced decay and other problems, although not visible to the naked eye, will lead to serious uneven heating of the cells inside the module and a significant drop in power generation, which can be detected by technical means. Through regular inspection and power generation tracking of the modules, if an obvious abnormality is found in the appearance of the modules or a significant and sudden decrease in power generation, it is suspected that the modules may fail. It is recommended that PV power plants that are in a position to do so be equipped with an infrared thermal imager to quickly discover and locate problematic modules by detecting differences in PV module surface film temperatures. After module failure is found, please contact the manufacturer for analysis and treatment in time.
23.How can I find out if a PV module in the PV array is malfunctioning?
A: When the user finds that the power generation of the system is reduced at the same time of the year, or compared to neighboring power generation systems with the same amount of installations. Then the system may be abnormal. Users can find out whether a particular module in the PV array is malfunctioning through abnormal fluctuation of monitoring data in the sink box, and then contact professionals to diagnose the system with professional equipment such as clamp meter and thermal imaging camera to finally determine the module in the system that has problems.
24.Will the PV module be damaged if it encounters a harsh environment such as hail?
A: First of all, according to the product description on the hail test results can be seen, its photovoltaic modules can withstand the best 44m / s speed, 35mm diameter hail impact, in the components of the compressive performance of a hit in other harsh environments working state has been certified by international professional bodies, followed by our general recommendation to owners of solar power plants to find a formal insurance company coverage, as long as the purchase of insurance encountered Natural disasters will get the corresponding claims.
25.The number of components in series or parallel when the PV power system is installed?
A: Do not use different types of modules in the same solar PV system. When the components are connected in series, the voltage of each string cannot exceed the maximum system voltage.
when the components are connected in parallel, it is recommended that the output current of the whole string of components is equal to the current sum of each branch component or component string. Each string of components should be installed with fuses, you can refer to the national or regional or local codes that
26.How to choose inverter? How to match the PV inverter with the module?
A: Generally, according to the requirements of the system configuration corresponding to the power section of the inverter, the power of the selected inverter should match the maximum power of the PV cell array, generally choose the rated output power of the PV inverter and the total input power is similar to about, so as to save costs.
Generally speaking, according to the 1:1 ratio to match can be, but the inverter are equipped with the ability to overmatch to more than 1.2 times.
27.Can the inverter and modules leak electricity?
A: No, only the system is installed in accordance with the PV system installation design, wiring solid, good grounding, there will be no such problems.
28, photovoltaic module surface damage to the components have an impact?
A: Damage to the surface of the module will cause the module to generate electricity abnormally and may cause leakage.
29、Is the inverter easily damaged?
A: No, you need to buy an inverter that meets the standard requirements of the PV industry, and they provide a five-year free warranty.
30、What is the reason for the low power generation of the inverter?
A: There are various reasons for the low power generation of inverter, which should be eliminated from all aspects, firstly, to determine whether the matching of PV panel and inverter is reasonable, and then to detect whether the PV panel and inverter work normally and whether the wiring of each component is firm.
31、Can the inverter be installed outdoors?
A: Yes, the product is designed according to IP65 grade, as long as it is not soaked in water, it can work normally, but when installed outdoors, you need to make sure that the machine is not exposed to direct sunlight, otherwise it will cause over-temperature drop.
32、Will the inverter consume power if it does not generate electricity at night?
A: Theoretically, there will be a little bit, because there is a filtering circuit at the output of the inverter, but this power consumption is particularly low.
33、What are the common types of photovoltaic bracket?
A: The material of PV bracket mainly includes aluminum alloy (A16005-T5 surface anodized), stainless steel (304), galvanized steel parts (Q235 hot-dip galvanized), among which stainless steel material has the highest cost, good weather resistance and high recyclable value.
Aluminum alloy brackets are generally used in solar energy applications on the roofs of civil buildings. Aluminum alloy has the characteristics of corrosion resistance, light weight, beauty and durability, but its low bearing capacity makes it impossible to be used in large solar power plant projects. In addition, the price of aluminum alloy is slightly higher than that after hot-dip galvanizing just now.
Galvanized steel bracket has stable performance, mature manufacturing process, high bearing capacity and easy installation, which is widely used in civil and industrial solar photovoltaic and solar power plants.
34、How to extend the service life of photovoltaic bracket limited?
A: ground photovoltaic mounting system, common ground photovoltaic system is generally used in the form of concrete strips (block) foundation. Solar photovoltaic racking design solutions face challenges, any type of solar photovoltaic racking design solutions for components to accessories, the most important feature is weather resistance. The structure must be reliable and able to withstand atmospheric erosion, wind loads and other external effects. Safe and reliable installation, maximum usage with minimum installation cost, almost maintenance free and reliable maintenance are important factors to consider when choosing a solution.
35、How often do I need to clean the general components? What do I need to pay attention to when cleaning?
A: According to the product supplier’s instruction manual for the components that need to be checked regularly for maintenance, the main maintenance work of the system is to wipe the components, rainfall areas generally do not need manual wiping, non-rainy season about once a month cleaning. Areas with high dustfall can increase the number of wiping as appropriate. Areas with high snowfall should remove the thick snow in time to avoid affecting the power generation and uneven shading produced by melting snow, and clean up the number of shading components or debris etc. in time.
In order to avoid electric shock injury to the person and possible damage to the module under high temperature and strong light, it is recommended to clean the module in the morning or later in the afternoon. It is recommended to use a soft brush and clean and mild water when cleaning the glass surface of the PV module, and use a small force when cleaning to avoid damaging the glass surface, and pay attention to avoid damaging the coating layer for the module with coated glass.
36.How to deal with the common failures of household distributed photovoltaic power generation system?
A: When the system has problems during the warranty period, you can contact the installer or operation and maintenance provider by phone to explain the system problems, the installer or operation and maintenance provider will answer the questions according to the user’s description, and if you can’t troubleshoot the problems, we will send someone to the site for overhaul.
37.How to reduce the maintenance cost of photoelectric system?
A: It is recommended to choose the system components and materials market reputation, good after-sales service products.
Qualified products can reduce the rate of failure, users should strictly comply with the system product manual, regular testing and cleaning maintenance of the system.
38.How to use the correct downtime for maintenance?
A: The priority is to choose the early morning or evening light system is not running time for the system maintenance, maintenance measures to do a good job of protection wear insulated gloves and use insulated tools.
39. distributed photovoltaic power generation system application scope and installation methods?
A: Distributed photovoltaic power generation system can be installed in any place where the sun shines, including the ground, the top of the building, side elevations, balconies, etc., which is most widely used in schools, hospitals, shopping malls, villas, residents, factories, enterprises and institutions roof, carports, bus stop top; installation methods are concrete, color plates and tile type three types.
40.Will the shading of houses, leaves or even bird droppings on the modules affect the power generation system?
A: If the modules are shaded, the power generation efficiency of the system will be reduced and the power generation will be significantly less than that of other unshaded systems.
The electrical characteristics of the solar cells used in each module are basically the same, otherwise there will be a so-called hot spot effect on the cells with poor electrical performance or shaded cells (problem cells). A solar cell module shaded in a tandem branch will be used as a load to consume the energy generated by other solar cell modules with light, and the shaded solar cell module will heat up at this time, which is the hot spot phenomenon, and this phenomenon can seriously damage the solar cell. Some of the energy produced by the illuminated solar cells may be consumed by the shaded cells. In order to avoid hot spot in series branch circuit, it is necessary to install bypass diodes on PV modules, and in order to prevent hot spot in parallel circuit, it is necessary to install DC insurance on each PV string.