What Should I Choose About The Components Of The PV System?
Solar Modules
Battery modules are divided into monocrystalline, polycrystalline and amorphous modules. Monocrystalline has the highest power generation efficiency and can generate more electricity in the same area, so it is most suitable for small installation area, but the unit price will be higher. The efficiency of polycrystalline silicon is the second highest, and it is more economical to choose polycrystalline silicon for a richer installation area, and the price is relatively low. Amorphous silicon has the lowest efficiency and is generally not recommended. In the selection of battery components there are five very important parameters: peak power, open circuit voltage, short circuit current, operating voltage, operating current. There are different sizes of battery modules according to their power, and the power of a single module ranges from 10W-300W. The size of the single module power is proportional to the area, so while choosing the power, you should also choose the most suitable size of the battery module to meet your installation space requirements.
Inverter
As the interface device between PV modules and the grid, the inverter converts the DC energy of PV cells into AC energy and transmits it to the grid, playing a crucial role in the grid-connected PV power generation system. There are two types of grid-connected inverters, one is a centralized grid-connected PV inverter with a minimum power of 1kw and an input voltage ranging from 150V to 550V. The other is a miniature grid-connected PV inverter, generally used in AC220V voltage level, power from 200W to 500W between the input voltage range of 12V ~ 28VDC. two kinds of grid-connected inverter usage is very different. The centralized grid-connected inverter is generally larger and suitable for wall mounting, while the miniature grid-connected PV inverter is small and generally installed close to the battery module (it can be installed on a bracket under the battery module), and both types of distributed grid-connected PV power generation systems for residential use are available. The main parameters of the inverter are maximum input power, maximum input voltage, rated input voltage, start voltage, MPPT voltage range, and output grid voltage. The selection of inverter is mainly to choose the rated power and the input and output voltage level. Then the user can easily determine the input voltage range of the grid-connected inverter according to the voltage level and series-parallel connection method of the selected battery components, and choose single-phase or three-phase output according to the power consumption of his home. Cable. The cable can choose the PV special cable, but the price is high, the amount is also bad to buy. Short distance or use the cable in accordance with the 1 square millimeter of safety current of 6A can be calculated. For example, the power of 3kw system, for photovoltaic input cable, the inverter's rated input voltage voltage DC350V, then the current is 3000W/350V = 8 ≈ .57A, choose BV2.5 cable. For the inverter output cable, the inverter's rated output voltage voltage is AC220V, then the current is 3000W/220V ≈ 13.63A, theoretically you can also choose BV2.5 cable, but for safety reasons can improve a grade, choose BV4 cable.
Lightning protector
Lightning arrester and ordinary lightning arrester is not the same, to choose the PV special high-voltage DC lightning arrester, because the continuous working voltage of ordinary lightning arrester is AC220V or AC380V, the continuous working voltage of the PV special lightning arrester can be as high as DC1000V.
Metering instruments
The power company will install two meters for free, one for measuring the electricity generated by PV and the other is a bi-directional metering meter, i.e., a meter that measures the electricity used by the user himself and the electricity sold to the grid [2]. This allows the customer to see in real time their daily electricity consumption, generation and transmission to the grid.
The last point please note Installation debugging installation if you are not familiar with the electrical system, it is best to ask qualified personnel to install. The series-parallel wiring of the battery panel board after installation is best done after the sun goes down to avoid high-voltage electrocution, while doing a good job of lightning grounding, in addition to pay attention to the wind resistance level of the bracket, the northern users should also pay attention to the snow resistance level. Debugging can be done together with the personnel of the power company.
