Improving the maintenanceOperations and works for the maintenance or recovery of efficiency, and smooth operation of the electricplants, taking into account any decrease in performance. level of grid systems has positive repercussions on the service quality and continuity. For these purposes and in order to rapidly identify and reach all systems, Terna uses a georeferencing system (GIS). Specifically, the following activity is performed:

  • MonitoringAll the actions through which the current operational status of an electricity system is ascertained. and checking of systems: in 2007, in addition to the controls established by the Law, approximately 10,700 periodic surveillance/technical inspections were performed on substations at various voltage levels. Repeated visual checks on company-owned lines were also performed for a total of 85,000 km of circuits inspected, 2,000 of which were performed by helicopter.
  • Routine maintenanceActivity carried out on plants or parts of plants for maintenance or recovery of efficiency and correctfunctioning, in relation to a fall in performance, without any modification of the number or function of theplants involved. Routine maintenance is defined as:• periodic or cyclical if the activity regards regularly scheduled interventions independent of external causes; • conditional or predictive if the activity follows the verification or monitoring of plant functionality; • occasional if the activity follows upon the existence of anomalies. Occasional routine maintenance is divided into: • deferrable maintenance, if the execution of the activity may be delayed by at least one week from the moment that Terna is notified of the anomaly; • non-deferrable if the execution of the activity, based on the owner’s evaluation, must be performed immediately and no more than one week from the notification of the anomaly to Terna, in order to avoid danger to persons or things, or the existence of a fault; • on the fault, if the activity follows upon the existence of anomalies.: Terna carries out maintenance according to an "operational" policy, i.e. maintenance to be performed based on signs of major or reduced deterioration identified from the information obtained from the integrated remote control operation, from online sensors and during monitoring of systems and substations. To manage the maintenance of power lines and substations, Terna uses a system called MBI (Maintenance and Business Intelligence) which enables optimization of maintenance. The MBI system has been in use within the company since 2005.
  • Work under high voltage: Almost 3,000 works have been carried out. These works are carried out while the line is in operation and increase the availability of the systems; consequently, they contribute to improving service quality and continuity.

Extraordinary maintenancePerformed for the recovery and extension of the useful life of a plant, without modifying the functionalconsistency or technical characteristics, as specified in Attachments 1, 2a and 2b of the Operator-Owner:

  • Regarding power lines, in addition to the complete reconstruction of 15 km of the 150 kV(kilovolt=1,000 Volts) unit of measurement of voltage. line, 400 pylons were renovated, 500 km of conductors, 600 km of guard wires and 1,100 insulator chains;
  • Regarding substations: 52 bays were renovated and 4 transformers were replaced.
  • Maintenance activities also include cutting down plants to prevent possible contact between vegetation and conductors, as well as related risks of short circuits, line interruptionCondition in which the voltage of the terminals delivering electrical energy for a user is lower than 1% of therated voltage. and fires from breaking out. Monitoring lines is also aimed at evaluating vegetation growth and other risk factors such as falling trees; measures applied on the vegetation normally consists of cutting or trimming and in cases of environmental regulations, in cutting off branches. In no case are herbicides used.

The main activities carried out in 2007 to improve the reliabilityThe fulfilment of two conditions:• availability: capability to respond, statically and in every moment, to the customers’ global demand for power and electrical energy at the connection points, taking into account planned and forced going off-line of the components of the electricity system; • security: capability torespond to sudden disturbances such as short-circuits or forced loss of components of the electricity system. Thus, this aspect specifically considers transition effects which are not covered by the first criterion. of systems and accelerate measures carried out to eliminate faults or anomalies were the following:

  • at the experimental level, the first Disconnecting Switch was installed for remote control implementation of safety measures on line and land switches;
  • changes are being studied to be applied to existing command and control protection systems for allowing the remote control of the functions "Special Activity Operation", in order to safely carry out work along the power lines with traditional methods or while the lines are in operation, without the need to send technicians to the stations;
  • a work group was created to define working methods for carrying out technical controls in the stations with the methodology of working under high voltage;
  • a massive TA replacement campaign was carried out with similar insulated devices with SF6, which are intrinsically much safer;
  • a multi-year campaign began for implementing local communication infrastructures in the electricity stations for introducing and applying monitoring technology and remote control diagnosing. For 10 Electricity Stations, fibre optic LAN were built to evaluate the already existing assets and for obtaining via remote control any information regarding the identification of the point of malfunction along the high voltage line in order to accelerate repair measures. All the last generation oscilloperturbographs were also built in the remote control mode.
  • an experimental campaign also began for instrumental control with an ultraviolet camera (Daycor) for examining the corona effect on insulators, conductors and clamps;
  • the campaign continued to replace glass insulators with other insulators made of composite materials or silicon resin coated glass: these solve the problem of grid vulnerability in areas with strong saline or industrial pollution;
  • in order to further increase personnel safety, the Remote Control Voltage Device was also introduced; this device is used before working on the systems to verify the presence of voltage.


tools invia un commento alla pagina aggiungi ai preferiti segnala ad un amico scarica il pdf vai al mio basket Aggiungi al mio basket stampa la pagina
Read aloud this page