The term photovoltaics is made up of the Greek words photon (sun) and voltaik (tension). It is used to describe the conversion of solar energy into electricity. The chemical element silicon plays a key role in this. It is obtained from normal sand and has a conductive function when irradiated by the sun. It is main component of a solar cell. Phosphorus is additionally applied to the top surface and boron to the bottom, resulting in an imbalance of electrons (5 on the top compared with 3 underneath). Because the electron endeavour to achieve a balance with 4 electrons on each surface, a voltage is built up, and because silicon has 4 electrons, it is the ideal transporting medium (semi - conductor).
The basic unit of a photovoltaic system is the PV module or panel, in which a certain number of solar cells are electricity connected to each other. Several modules linked to one another then form a solar generator. The Direct Current (DC) they produced is conveyed via a suitable wiring systems to the inverter, which converts it into Alternating Current (AC). As a result, the electricity generated by a PV unit can be fed via a meter into the public grid and utilized in the normal ways.
The average service life of a PV system is 30 - 40 years, while the module manufacturers give a guarantee of between 10 and 25 years. Generally speaking a PV unit requires little maintenance and has minimum susceptibility to malfunctions or breakdown.
As a rule thumb, we can say that, at our latitudes, between 800 and 1000kWh of electricity is produced per kWp of installed capacity. A 3 kWp unit generates in a year about the same amount of electricity as in needed annually by a 3 - 4 person household with a moderate electricity consumption.
Every inverter is secure against atmospheric damage through thermally controlled voltage - dependent resistors, also called "varistors". These varistors are triggered if lightning strikes something nearby. The inverter can only be insured against a direct lightning strike through special insurance cover.
You will need a site plan, a layout plan of the solar unit with the nominal data of the individual components, a description of the protective devices with information on the type, make, circuit and function, a declaration of conformity for the inverter, details of the short - circuit resistance of the switch elements, an application for a meter and a certificate from the company installing the unit.