The transfer of electricity from producer to consumer is called “transmission”. This activity is carried out through a complex and structured system comprised of various assets: power lines, plants and electrical devices for switching, regulating and transforming electricity.
The transfer of electricity from producer to consumer is called “transmission”. This activity is carried out through a complex and structured system comprised of various assets: power lines, plants and electrical devices for switching, regulating and transforming electricity.
From the production centres, high-voltage and extra-high-voltage power lines transfer the electricity to transmission hubs called electrical substations. Based on its function, the electricity is classified into switching stations through lines at the same voltage level, transformer stations through lines at different voltage levels via transformers, conversion stations through direct current (HVDC) lines, and conversion systems through alternating and continuous current. The high-voltage lines that provide electricity to the primary transformers are supplied by the substations. In Italy, Terna manages more than 870 electrical substations.
The transmission grid interfaces with the distribution network through primary transformers, electrical plants whose function is to transform high-voltage energy into medium-voltage energy (8.4, 10, 15 or 20 kV). In addition to powering the distribution grid, transformers supply energy to both industrial users and large commercial users. This medium-voltage energy then goes to secondary transformers to be transformed to low-voltage energy and distributed to end users, such as shops, offices and homes. In Italy, there are around 2000 primary transformers.
The voltage of electricity is raised and lowered through the use of transformers, electrical devices which allow energy to be connected and transferred between different voltage grids. Because of the transformers, the energy produced at medium voltage in the power plants is first transformed into high- and extra-high voltage to then be brought back to a lower voltage level near the end users. This ensures that the energy is transported efficiently, given that, for the same amount of power transmitted, the greater the voltage, the lower the grid losses along the power lines. In Italy, Terna has 781 transformers on its grid.