Infrastructure maintenance

Infrastructure maintenancePlant maintenance is essential for ensuring service quality and continuity.
To ensure that plants can be identified immediately, especially in the event of malfunctions, as well as reached as quickly as possible, Ternai uses a handheld medium integrated with a navigation system that shows all the plants superimposed on a geo-referred map.  

The main actions performed in 2010 with regard to electric stations and lines were the following:  

Plant monitoring and inspection: in addition to the checks prescribed by the law, Terna:

  • performed about 11,400 periodical technical and surveillance checks on stations at the different voltage levels
  • inspected about 91,000 km of three-phase circuits with on-site checks, including about 4,100 km by helicopter, amounting to about 2 inspections of the grid a year;
  • 24,300 instrumental checks of lines, including the use of thermal cameras to identify hot points and DayCor UV cameras to pinpoint the corona effect on insulators and conductors.

Ordinary maintenance: Terna identifies the work to be done on the basis of deterioration signaled by the integrated remote-management system, online sensors, and plant monitoring.

Controlling vegetation: the proper operation of lines also requires continual monitoring to assess the growth of vegetation in order to prevent the latter from getting too close to the conductors and the consequent risk of short circuits and line interruption. Vegetation control normally consists in cutting it down to the ground or – if there are particular environmental restrictions – in branch removal aimed at keeping trees at a safe distance. Herbicides are never used.    
During 2010 vegetation was cut along 12,200 km of electric lines.

Work on live wires: maintenance work on live wires was performed about 2,200 times.
Performed with the line in operation, such work increases plant availability and contributes to the improvement of service quality and continuity.    

Special maintenance: during 2010 Terna reconstructed 24 km of 220-kVi lines and 27 km of 132-/150-kVi lines.