Project: San Pellegrino Pass
Location: Italian Alps
Cable type: 132 kV cable
Tratos & TERNA cooperation
TERNA, a large Italian operator in electricity transmission grids, invited Tratos to install a high load carrying, low sag conductor in the San Pellegrino Pass in the Alps, on the 132 kV Moena-Cencenighe overhead line. The installation process of the 132 kV cable proved to be comparable with those of a traditional conductor of a similar size.
A report prepared by the OEM after of the installation said: “The installation of the line at high altitude (2,000 meters above sea level) is a severe test for the conductor: in fact, at low temperatures the mechanical load is transferred from the carbon core to aluminium alloy coats, determining a state of high stress for the latter.”
Very low ambient temperatures are detrimental to overhead lines because cable reduces in length increasing mechanical tension applied to the pylons (in really severe cases pylons can be damaged or even collapse). Expansion and contraction in the aluminium tension applied to this relatively fragile material (instead of high strength carbon), can lead to excessive permanent elongation or even wire breakage and, at low temperatures, ice can grow on the conductor, causing a considerable weight gain, dramatically raising tension within the conductor.
The solution was to increase the current-carrying capacity – with a newly developed, non-traditional conductor whose mass is not very different from a traditional ACSR (Aluminium Conductor Steel Reinforced) type.
For this 132 kV cable were used innovative new materials, in particular an alloy with high conductivity, a maximum tensile strength comparable to pure aluminium and, more importantly, a maximum strength that remains unchanged at high temperatures. With this new alloy, it is possible to build a replacement conductor with high thermal limits, working at temperatures not attainable with traditional counterparts.
New heat resistant materials combined with detailed attention to overall design resulted in the greatest increase in the conductors ‘current-carrying capacity. These new conductors simply replace existing conventional steel reinforced counterparts in transmission lines using existing pylons and towers, with the added benefit of a reduction in sag.
The conductor operated successfully without problems for several years before it was carefully removed, examined and re-evaluated by TERNA. The results of this work showed no deterioration in the Tratos OHC-HV.
Terna is one of Europe’s main electricity transmission grid operators, managing the high voltage Italian transmission grid, one of the most modern and technologically advanced in Europe. They play a central role, as directors in the transition of the electricity market towards the use of environmentally friendly sources, guaranteeing a secure and efficient supply to households and businesses
The Terna group is the owner of the Italian national transmission grid (NTG) for high and extra-high voltage power and is the largest independent electricity transmission system operator (TSO) in Europe. They have a public service role, crucial to ensuring the country’s power supply and enabling the entire Italian electricity system to function.
Terna promote the energy transition and sustainable development by focusing on people and innovation. Every day, they work to build an atmosphere of dialogue and trust in local areas, to which we bring a vital asset for everyone’s economic and social lives: electricity. This translates into choices based on respect for the environment and local communities. Their inclination to listen begins within the Company, among our people, in the awareness that the radical transformation the world is experiencing is a shared responsibility. This responsibility is their energy.
Did you know?
According to the Market Research Future report, one of the key concerns in the transmission of electricity is the interruption in the supply of power. High voltage cables allow transmission of power at longer distances without considerable losses. With advancements in power sector and the desire to gain high-quality supply of electricity, industries have come up with the highest voltage level of above 500 kV.
High voltage cables are made of electric conductor materials that are capable of enduring high resistances, and thus, decrease the resistance and losses that are in the form of heat. Also, the high voltage accessories are excellent protectors of transmission and distribution systems from moisture, mechanical wear out, as well as they are connectors of conductors, along with the earthing links. High voltage cables are used for carrying electric power to areas where there is no power generation utility. Also, high voltage accessories ensure efficient and uninterrupted electricity T&D as well as they provide reliable and durable solutions for transmission of high voltage current.
High voltage cables and accessories market is driven by the factors such as increased demand for electrical power from remote areas and growing urbanization projects, increasing grid connection projects, and rising demand for reduction of losses in transmission and distribution network. The increasing oil rigs in the offshore regions need on time power for smooth operations, and high voltage marine cables allow the power to reach the offshore oil production facilities. However, safety issues related to overhead accessories and cables is restraining the market for high voltage cables and accessories.
San Pellegrino Pass
San Pellegrino Pass, a wide mountain pass 11 km away from Moena, marks the border between Trentino and the Belluno province. Equipped with state-of-the-art lifts, the whole skiing area offers over 100 km of slopes of various length and difficulty, linked by the carousel of the TreValli Moena-Alpe di Lusia, San Pellegrino, Falcade.
The mountain pass offers hospitality in its various prestigious hotel accommodation, allowing direct access to the slopes and granting an ideal solution for those who wish to enjoy a full day of skiing on the ever-sunny slopes.
Visitors will never forget the view from this spectacular balcony at 2,500 metres in altitude, featuring Marmolada, the Queen of the Dolomites. Nordic ski lovers will be familiar with the Alochet cross-country ski centre, which is part of the national Nordic Super Skipass circuit, featuring ski-runs surrounded by beautiful woods.
Participating in this project, Tratos supported the Italian authorities’ endeavours to achieving the 17 UN Global Goals: Goal 7 to ensure access to affordable, reliable, sustainable and modern energy for all, Goal 9: Industry, Innovation and Infrastructure, Goal 13: Climate Action, GOAL 3: Good Health and Well-being, Goal 14: Life Below Water, and Goal 11: Sustainable Cities and Communities.