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THE ONE-SIZE-FITS-ALL SOLUTION OFFERS MANY ADVANTAGES

The innovative repair solution for the offshore industry is based on the plug-in epoxy resin joint up to 170 kV from the CONNEX product family from PFISTERER for connecting high-voltage cables. This technology is already in use on numerous offshore wind and oil platforms as a connection between platform cables and export cables. The joint housing and internal optical fibre connection system were developed by the British engineering company Power CSL. The housing is highly robust and makes the CONNEX connection solution completely waterproof and suited to underwater use. “The universal repair joint can be used for any polymeric-insulated HVAC subsea cable up to 170 kV and can be installed independently on any cable thanks to the plug-in principle. This offers a lot of flexibility in planning. All three phases in the subsea cable are connected in parallel to a centrally prefabricated unit in a single plug-in procedure. This saves valuable assembly time at sea and reduces the number of spare parts required,” says Vukašin Basara, Senior Product Manager at PFISTERER.

PFISTERER was awarded the contract to develop the innovative universal joint by TenneT, one of Europe’s leading transmission system operators based in Germany and the Netherlands. In addition to developing and designing the repair joint, the order also included performing all type tests for mechanical and electrical product qualification in accordance with IEC 60840 as well as CIGRÉ 490 and 623.

EFFICIENT REPAIR MANAGEMENT

The client TenneT operates offshore grid connection systems in the North Sea off the German and Dutch coasts, to transmit wind power from sea to land. The electricity generated in the wind farm is transmitted as AC power to a converter platform, where it is converted for further transmission. Multiple AC cables from various cable manufacturers are installed between the wind farm and the converter platform. There are also some direct three-phase connections from sea to land. If a cable fault or interruption occurs at any point, for example due to ageing cables or mechanical impact, it was previously necessary to keep spare cables, repair joints, and spare parts in stock for each specific connection in order to be able to respond as quickly as possible. This ties up considerable logistics capacity, time and costs.

The universal repair joint now provides a solution that significantly simplifies the repair of defective HVAC subsea cables – with minimal need for spare parts and assembly tools. As a result, TenneT can siginificantly reduce its spare part inventory.

UNIVERSAL SUBSEA CABLE REPAIR JOINT UP TO 245 KV

In addition to the plug-in version for up to 170 kV, there is also a slip-on repair joint available for high-voltage subsea cables up to 245 kV. It utilizes the same mechanical components as the 170 kV solution, with a central joint body that enables the connection of cables with different conductor cross-sections and geometries.