Elements of a photovoltaic solar system

A photovoltaic solar installation is an installation whose objective is the generation of  electricity  through  solar radiation . Therefore, it is a  renewable energy source .

The components of this type of installation will vary depending on whether it is a solar plant connected to the power grid or is an isolated solar installation. In any case, the difference between both systems is based on the management of the generated energy.

In isolated installations, the generated electrical energy can be used directly or stored in solar batteries. In the case of facilities connected to the network, the  electricity  generated is supplied to the general electricity network for distribution.

Common elements of a photovoltaic solar installation 

Despite the differences between the facilities connected to the network and the autonomous facilities there are some common elements:

• The  photovoltaic panels .
• The  current inverters .
• Solar trackers.
• Electrical wiring

Photovoltaic panel 

The   photovoltaic solar panel is the element that captures  solar radiation  and is responsible for transforming solar energy into  electricity  through the  photovoltaic effect . The  photovoltaic panels  are composed of  solar cells .

The  photovoltaic cell  is the part of  the photovoltaic panel  responsible for transforming  solar radiation  into  electrical energy  thanks to  the photovoltaic effect . The result is an  electric current  in  direct current .

Generally, a photovoltaic solar module or panel consists of an association of  photovoltaic cells . This association is encapsulated in two layers between a front glass sheet and a back layer of a thermoplastic polymer or other glass sheet.

The glass sheet is used when you want to obtain modules with some degree of transparency, usually this set of elements is framed in an anodized aluminum structure. The objective of this aluminum structure is to increase the mechanical resistance of the assembly and facilitate the anchoring of  the photovoltaic module  to the support structures.

The   most commonly used photovoltaic cells in  photovoltaic panels  are  silicon , and can be divided into three subcategories:

• The  photovoltaic cells  of  monocrystalline silicon  are constituted by a single crystal of  silicon . This type of cells has a uniform dark blue color.
• The  photovoltaic cells  of polycrystalline silicon or multicrystalline are constituted by a set of crystal  silicon , which explains its performance is somewhat lower than monocrystalline cells.
• Amorphous silicon cells. They are less efficient than  crystalline silicon cells  , but also less expensive. This type of cell is, for example, the one used in applications such as calculators or small devices that do not require a large amount of energy.

I power inverters

The  inverter  is an electronic device responsible for converting the  direct current  generated in  alternating current .

The   photovoltaic solar panel provides  electricity  in the form of  direct current . This current can be transformed into  alternating current  by means  of the current inverter  and injected into the electrical network or into the internal network.

The simplified process would be as follows: Energy is generated at low voltages (380-800 V) and in  direct current . It is transformed with an  AC inverter  into  alternating current . In power plants of less than 100 kW, the energy is injected directly into the low voltage distribution network (400  volts  in three phase or 230  volts  in single phase). And for powers greater than 100 kW, a transformer is used to raise energy at medium voltage (up to 36 kV) and is injected into the transport networks for subsequent supply.

Solar trackers

Solar trackers are mechanisms that guide the position of photovoltaic panels depending on the position of the Sun to increase their performance. Its use is quite common in the production of solar energy.

Solar trackers allow solar production to increase considerably, around 30% for the former and an additional 6% for the latter, in places of high direct radiation.

There are solar trackers of various types:

• Solar trackers in two axes: the surface of the  photovoltaic panel  is maintained always perpendicular to  the sun .
• Solar trackers on a polar axis: the surface of  the solar panel  rotates on an axis facing south and inclined at an angle equal to latitude. The rotation is adjusted so that the normal to the surface at all times coincide with the terrestrial meridian containing the  sun .
• Solar trackers on an azimuthal axis: the surface rotates on a vertical axis, the angle of the surface is constant and equal to latitude. The rotation is adjusted so that the normal to the surface at all times coincide with the local meridian containing the  sun .
• Solar trackers on a horizontal axis: the surface rotates on a horizontal axis and oriented in a north-south direction. The rotation is adjusted so that the normal to the surface at all times coincide with the terrestrial meridian containing the  sun .

Electrical wiring

Electrical wiring is the element that carries  electrical energy  since its generation, for later distribution and transport. Its dimensioning is determined by the most restrictive criterion between the maximum potential difference and the maximum admissible intensity.

Òbviously, the dimensioning of electrical wiring is much greater in the case of solar installations connected to the grid, than isolated solar installations. In the case of isolated installations, it is only necessary to transfer the  electrical energy  locally, generally to the   electric batteries .