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Viking Link team completes the onshore cable installation

Work on the worlds longest power cable interconnector linking the UK and Denmark is running on schedule to meet end-2023 delivery despite external challenges including the Covid – 19 pandemic and raw material shortages, said the Prysmian Project Director on Viking link Giuseppe Cardamone.

 

The Viking Link calls for the design, manufacturing and installation of approximately 1400 kms of cables, 1250 kms submarine cables and 135 kms land cables. More in details, the cables system consists of two poles each one approximately 700 km long installed between the UK converter station located in Bicker Fen, in Lincolnshire, and the landfall located at Houstrup Strand beach, in Denmark.

The 1250 km submarine power cables are laid by Prysmian’s cable laying vessels in a bundle configuration. For the first 150 km of the cable route from both UK and Danish shore towards the mid-sea a Prysmian fiber optic cable is laid in bundle together with the two power cables.

“The installation of the submarine cables started in 2021, when the first two installation campaigns were installed by Prysmian’s owned cable laying vessels Cable Enterprise and Leonardo da Vinci; in 2022 three additional offshore sections were installed by the two vessels reaching an overall length of 870 km of submarine cables installed and protected”

Giuseppe Cardamone

Prysmian Project Director on Viking Link

The installation of the 135 km UK land cables section between the converter station and the landfall located on a beach in Lincolnshire has been completed. Viking Link’s Prysmian team achieved a key milestone at the beginning of February 2023 when the jointing activities of the 135 km land cables carried out by Prysmian’s trained cable jointers have been completed.

This has paved the way for a high voltage intermediate test of the entire onshore section.

Upon completion of the intermediate HV test, Prysmian’s jointers will install the sea/land transition joint of both poles connecting the UK onshore section with the offshore section of the interconnector.

“2022 has been a successful year,” said Giuseppe Cardamone. “Despite the Covid-19 pandemic imposed to adopt rigid safety procedures, like reduction of personnel to avoid virus contamination and quarantine period and Covid tests for all personnel mobilized offshore onboard Prysmian’s vessels, and the raw materials availability shortages due to the war period, we were able to continue both the manufacturing and installation of the cable in accordance with the Project Schedule”

Viking Link is a 1400 MW HVDC submarine power cable between the United Kingdom and Denmark and its operating voltage will be 525 kV. When completed in 2023 it will enable the more effective use of renewable energy – allowing the exchange of energy surplus between Britain and Denmark – access to sustainable electricity generation for over 1.4 million households, potentially reducing the cost of electricity and reinforcing the system reliability ensuring zero-carbon generation.

The Contract, with a value close to € 670 million, was awarded to Prysmian in August 2019 by the UK and Danish Transmission System Operators, National Grid and Energinet, and includes the turnkey design, manufacturing and installation of the cable system.

The cable landing in Denmark was performed in March 2022 by one of the Prysmian’s vessel Cable Enterprise. The cable landing operation was carried out with the assistance of a landfall Subcontractor providing resources and equipment both onshore and offshore. Cable Enterprise was moored at approximately 1,5 km distance from the shore. Simultaneously, meanwhile the vessel was laying the cables an onshore winch, whose wire was initially connected to the cable head, was pulling the cables to shore. Cables were maintained in a floating configuration with the help of floaters installed on the cables before leaving the vessel deck. The cable pulling operation was supported by several working boats which handled and controlled the 1.5km long cables floating string guaranteeing the operation was performed safely and in accordance with the installation procedure and within the cable design parameters. Once the cable head reached the final location on the beach the floaters were removed by divers to allow the cable laying on the seabed. During summer season the cables were buried using water jetting equipment.

“The key to the successful cable landing operation was the good planning and preparation of the activity sequence and the efficient communication and coordination between Prysmian’s vessel and Subcontractor onshore personnel managing the overall operation both offshore and onshore”,

said Giuseppe Cardamone.

At the Danish landfall in spring 2023 Prysmian’s jointers will install the sea/land transition joints of both poles connecting the submarine section to the Danish land cables section running from the landfall to the convert station located at Revsing in South Jutland, Denmark.

Gearing up to finish during 2023 summer with the Omega joint

In April 2023, Leonardo da Vinci will start laying the two remaining offshore campaigns installing in bundle the last 380 km of submarine cables needed to close the link in the middle of the North Sea, expected to be completed by early July 2023. To achieve this, the Leonardo da Vinci crew will first recover the two cable ends that arrive mid-sea from UK shore, lift the cables on the vessel deck and joint them with the new sections of cables. Afterwards, Leonardo da Vinci will lay the cables in bundle configuration up to the cable route location where the ends of the cables arriving from the Danish shore were previously laid. At that stage in order to close the link, the Leonardo da Vinci will recover on the deck the two ends of the cables arriving from the Danish shore and execute an “Omega joint” with the cables arriving from UK shore still on the vessel deck. Once completed, the Omega joint will be deployed on the seabed. At that stage everything will be ready to carry out the End-to-End High Voltage Test of the Viking Link cable system.