Transmission & distribution |


Cable laying: Aurora goes to great lengths, and depths


Recent contracts awarded to Nexans, notably those for the Tyrrhenian Link in the Mediterranean and for power-from-shore cables to supply Equinor’s Oseberg field in the North Sea, will make full use of the capabilities of its new cable laying vessel Nexans Aurora


Under a €650 million contract with Terna, Nexans is supplying interconnector cabling for the TSO’s Tyrrhenian Link, connecting Sicily, Sardinia and the Italian mainland (Campania). As part of the contract, Nexans will manufacture and install 500 km of 500 kV mass-impregnated (MI) cable and fibre optic cable at more than 2000 m water depth, the deepest yet for a subsea power cable in the Mediterranean.


The project will help increase electricity exchange capacity and support the development of renewable energy flows. In addition, it will strengthen network stability and security as well as increasing competitiveness for producers in the local electricity markets.


For the installation of the interconnector cable, Nexans will use its new cable laying vessel Nexans Aurora, which can install cables in depths of over 2000 m and can accommodate a 10 000 t cable payload – enabling the cable laying to be accomplished in one campaign. Nexans Aurora will also be used to install a power cable system to deliver electricity directly from the Norwegian power grid to Equinor’s Oseberg oil and gas field as part of an 80 million euros contract.


The cable system will provide renewable energy to the field and the contract can be seen as part of Equinor’s efforts to reduce its carbon footprint.


Oseberg is located in the North Sea, around 140 km north west of Bergen.


The cable system consists of one 3-core 132 kV AC cable with the capacity to supply 180 MW to the main platform at Oseberg. The power cables will include two fibre optic cables, each fitted with 48 SM fiber optic elements. They will be connected to a central DTS system that allows


operators to detect early warning signs of any issues in the cables.


The cables will be manufactured at Nexans’ plant in Halden, Norway, with installation due to start in 2023.


The power-from-shore cable system will allow Oseberg to operate using low carbon hydropower. Nexans unveiled Nexans Aurora in September at a ceremony at its Halden cable manufacturing facility in Norway.


Nexans describes the new vessel as a “first of its kind in the offshore cable-laying sector”, with a 75 t specially designed cable capstan provides “market leading capacity for installation of cables in deep waters of 2000 m and beyond”, thanks to the 10 000 ton cable payload capacity, and “in addition to deep water, the vessel also has excellent shallow water capabilities to get close to shore for cable landing operations.”


Torre Tuscia Magazzeno (Battipaglia)


It’s one of the few cable-laying vessels in the world that, as well as being able to provide links for offshore wind, can also support installation of interconnectors (eg, between countries), says Nexans.


Nexans already owns one purpose-built cable laying vessel, Nexans Skagerrak, and the new vessel takes “capabilities and capacity to the next level”, the company says.


The company is currently involved in a number of major offshore wind projects including: Seagreen and Moray West in Scotland; Empire Wind, South Fork Wind and other offshore projects in the USA; and Equinor offshore activities in Brazil. As well as the Tyrrhenian Link, Nexans is also involved in other interconnectors, such as a projects with ADMIE that will provide a 1 GW link between the island of Crete and Greece’s mainland network.


Terra Mala (Cagliari)


TYRRHENIAN LINK


• Double submarine cable line • Length 950 km • Power 1000 MW


Fiumetorto (Termini Imerese)


Above: Source of map: Terna Right: Nexans Aurora at the Halden cable manufacturing facility, Norway


28 | March 2022| www.modernpowersystems.com


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