PFISTERER to deliver SEANEX connection system for Seagreen

In: Windfarms
20/04/2021

SSE Renewables and Vestas have selected the offshore-optimised SEANEX inner cone system by PFISTERER to connect more than 100 wind turbines in the
Seagreen project in the Western North Sea.

PFISTERER is supplying SEANEX joints as well as preassembled and tested cables with SEANEX connectors for the construction. Each of the Vestas turbines will be connected using SEANEX accessories. The joints and preassembled cables link the submarine cables to the gas-insulated switchgear (GIS) in the tower of the turbines.

“We are pleased that our SEANEX solution has been selected for this project. This confirms that in SEANEX, we have developed a compact, robust connection system that is perfectly suited to 66 kV offshore wind farms,” said Dr. Peter Müller, Head of Renewables at PFISTERER.

"The SEANEX connection system has helped us simplify our fabrication and delivery activities by providing a clear interface point between the inter-array cables and the turbine, accelerating the project execution and saving time and costs while providing a permanently robust and secure connection." commented James Allan, Lead Engineer – Array Cables of Seagreen/SSE Renewables, summarizing the advantages.

“The connection system will provide an easier, quicker, cost efficient and safer approach to connect the wind turbine HV network to the array cable infrastructure in a pluggable variant. SEANEX ensures an end-to-end pretested configuration, allowing the possibility to test the entire array cable infrastructure prior to turbine installation, and will last as long as the turbine. It will also reduce the time for connecting the individual wind turbine generators (WTGs) to the array network, and still allow a primary gas-insulated switchgear in the transition piece to become redundant since it is directly connected to the WTG HV switchgear. It feels like plugging in your extension cord at home on a bigger scale,” explains Stephan Kremers, project manager at Vestas.

As the wind turbines are installed, the pluggable connection between the submarine cable and the tower cable allows the project partners’ individual construction phases to be clearly separated. In addition, the 39 cm long SEANEX cast resin joints are designed to be more flexible handling during the offshore installation process. They are solid-insulated and therefore SF6 gas free, resistant to salt water and UV radiation, and submersible. They are suitable for various cable types up to a diameter of 800 mm². In the Seagreen project, the XLPE insulated submarine cables are connected to the switchgear via flexible, preassembled and pretested “dropper cables”. At sea, when installing the turbine, it is simply a case of plugging the cable into the preassembled joint. This reduces the offshore installation time. The touch-safe, gas-free and maintenance-free inner cone fittings feature separate mechanical and electrical contacts which are stable in continuous operation under load.

PFISTERER will deliver the SEANEX fittings for the Seagreen project when construction starts in 2021.


The Seagreen offshore wind farm is located 27 km off the Angus Coast in the Firth of Forth. It will be developed and operated by Seagreen Wind Energy Limited. Once constructed, the wind farm will be the largest in Scotland. Phase One will feature 114 MHI Vestas V164-10 MW turbines and is expected to provide low carbon energy for more than one million homes. In September 2019, Seagreen secured a 15-year CfD contract awarded by the UK government. SSE Renewables is leading on the development and construction of the first 1,140 MW phase, supported by Total, and will operate the asset on completion, which is expected in 2022/23.

For more information on offshore wind farms worldwide, click here.

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