Infrastructure maintenance

Infrastructure maintenance is essential to ensure service quality and continuity.

To ensure that the Company is able to identify infrastructure immediately, especially if there is a malfunction, as well as to get to the one in question, Terna uses a georeferencing system integrated with a navigation system that shows all plants superimposed on the road network.

The main tasks performed in 2009 on electric stations and lines were the following.

Monitoring and checking infrastructure: in addition to the checks required by law, Terna:
  • carried out about 11,400 periodical surveillance/technical checks on stations at various voltage levels;
  • visually inspected about 95,000 km of three-wire circuits, including about 3,400 km by helicopter: about 2 inspections during the year of the entire grid;
  • performed 13,976 instrumental checks on the electric lines, using, among other things, thermal cameras to detect hot points and Daycor UV cameras to detect corona discharge from insulators and conductors.

Ordinary maintenance
: Terna decides the work to do on the basis of signals of degradation from the integrated remote-control system, online sensors, and the results of infrastructure monitoring. 

Vegetation cutting: the proper operation of lines requires continual monitoring aimed at assessing the growth of vegetation in order to prevent contact between plants and conductors, with the consequent risk of short circuits, line interruption, and fires.
Work on vegetation normally consists in cutting it down to the ground or, if there are environmental restrictions, branch trimming aimed at maintaining safety distances. Herbicides are never used.
In 2009, vegetation was cut along 11,416 km.

Work on live wires: maintenance work was carried out on live wires about 2,300 times. 

Extraordinary maintenance: during 2009, 6 km of 380-kV lines, 2 km of 220-kV lines, and 39 km of 132/150-kV lines were reconstructed.

Infrastructure maintenance