Each panel is made up of a large number of cells made of crystalline silicon, which is a semiconducting material. The cells directly convert solar radiation into electricity using the photovoltaic effect (semiconductor effect through which light that touches a photovoltaic cell triggers the movement of electrons). The cells generate electricity in direct current (DC). A photovoltaic solar generating station is made up of many panels interconnected in series.
Various types of photovoltaic panels can be found on the market. Two main types are single-face and bifacial panels. Single-face panels capture direct solar radiation that travels to the exposed side of the panel, while bifacial technology captures both direct radiation on the top of the panel and indirect radiation reflected from the ground on the underside of the panel.
Photovoltaic panels are attached to fixed metal racking or mobile racking known as “solar trackers”, which follow the path of the sun. Racking is generally anchored to the ground using piles. Depending on the geological profile of the site, these may be spud piles, driven piles, piles bored into rock or piles inserted into concrete bases.
The electricity produced by the series of photovoltaic panels travels to junction boxes along wires that are attached to the panel racking. Underground wiring then connects the junction boxes to inverters. Inverters are electronic devices that convert the direct current generated by the photovoltaic panels to alternating current (AC). Many panel series are connected to each inverter.
Generally, it is necessary to increase the voltage of the current that leaves the inverters so that it can reach the level required for the power grid. This is done by power transformers. When the electricity leaves the transformers, it goes through the station’s collector system, which is made up of underground wires.
The collector system ends at the switchyard of the photovoltaic solar generating station. This is the interface that connects to either the transmission system or the distribution system, as applicable.