A grid-connected photovoltaic solar installation has the following basic elements:
- A group of photovoltaic solar panels to transform solar radiation into electrical energy.
- An electric power inverter. The inverter allows the energy to be transformed into direct current generated by the panels into alternating current.
- A box of interconnection with the electrical network trades.
- An electric meter ..
Photovoltaic panels are the most important elements for the use of this renewable energy, they are a type of solar panel whose function is to convert solar irradiation into electrical energy. It is the most important part of the solar system and is common both in grid-connected systems and in isolated photovoltaic installations.
Electronic inverter-converter or inverter. This device transforms the energy in the form of direct current provided by the solar panels, into alternating current of the same type and value as that carried by the electrical network.
What function do photovoltaic panels have?
These panels are usually located on the roof of a building or integrated into any structural element of the same building. The photovoltaic panels can also be arranged directly on any terrain near the electrical network.
Types of photovoltaic panels
There are three types of photovoltaic panels:
- Monocrystalline silicon photovoltaic solar panel. They are the silicon that is purest and, therefore, the most efficient.
- Polycrystalline silicon photovoltaic solar panel. This type of module is not as pure or as expensive as monocrystalline photovoltaic panels.
- Thin film photovoltaic panel. It is the quintessential domestic photovoltaic panel, because it is the cheapest of the three.
How do they generate electricity?
Photovoltaic cells are responsible for converting solar radiation into electricity through the photovoltaic effect. These cells are generally black or dark blue in color, associate in groups and protect themselves from the elements, forming photovoltaic modules.
Several photovoltaic modules together with the electrical cables that connect them and with the support and fixing elements, constitute what is known as a photovoltaic generator .
The photovoltaic generator is the element in charge of transforming solar radiation into electrical energy. This electricity is produced in direct current, and its characteristics depend on the energy intensity of solar radiation and the ambient temperature.
What is the function of the power inverter?
The power inverter is the element that transforms the electrical energy (direct current) produced by the panels into alternating current with the same characteristics as that of the electrical network.
There are different types of inverters, but it is considered advisable to choose it depending on the size of the installation to be performed.
Characteristics of inverters or current inverters
In any grid-connected photovoltaic solar installation project, the inverter is the heart of the system. It is very important to have clear technical characteristics:
- Inverter power
- Working ranges
- DC-AC voltage
- Maximum power reached.
The power accumulated by the number of inverters will determine the nominal power of the photovoltaic solar plant in any photovoltaic system connected to the grid.
For each photovoltaic grid connection system, we can find a whole range of equipment (expressed in nominal power) for use.
In systems where more than 100 kilowatts are already installed, the equipment can be rated at 10 kilowatts and up. Basically, the equipment that has in its technical characteristics the maximum protections established by current regulations is chosen, so that it results in an increase in system security and reduces installation costs in general.
The equipment that incorporates visualization, monitoring and control of the data and operating parameters of the entire system is also highly valued. The display display on the equipment and the software for monitoring on the computer are increasingly important.
The photovoltaic generator needs two meters located between the inverter and the grid.
One to quantify the energy generated and injected into the grid for billing, and the other to quantify the small consumption (<2 kWh / year) of the photovoltaic inverter in the absence of solar radiation. The second meter also serves as a guarantee for the electricity company of possible consumption that the owner of the installation could make.
The electricity consumption of the building will be carried out from the network, with its own meter, this being an independent installation of the photovoltaic system.