Scotland's largest offshore wind farm is under construction 27 km off the Angus coast. Seagreen is a joint venture between SSE Renewables and Total. For the construction, PFISTERER is supplying SEANEX joints and cables pre-assembled and tested with SEANEX connection parts. Each of the more than 100 Vestas V164-10MW wind turbines will be connected with SEANEX fittings. The joints and pre-assembled cables provide the connection of the submarine cables to the gas-insulated switchgear (GIS) in the tower.

"We are very pleased that our solution was selected for this project. This confirms that with SEANEX we have developed a compact, robust connection system that is perfectly suited to 66 kV offshore wind farms," says Dr. Peter Müller, Head of Renewables at PFISTERER. "The SEANEX connection system has helped us to simplify our manufacturing and delivery processes by providing a clear interface point between the array cables and the turbine. It speeds up project delivery, saves time and costs, while providing a durable, robust and secure connection," said James Allan, Lead Engineer - Array Cables at Seagreen/SSE Renewables, summarizing the benefits.

"In a pluggable variant, the connection system offers a simpler, faster, more cost-effective and more secure approach to connecting the wind turbine HV network to the array cable infrastructure. SEANEX ensures a pre-tested configuration throughout and provides the ability to test the entire array cable infrastructure prior to turbine installation. In doing so, it lasts as long as the turbine itself. The system also reduces the connection time of each WTG to the field network and by connecting directly to the WTG high voltage switchgear, it also eliminates the need for a primary gas insulated switchgear in the transition piece. It's like plugging in your extension cable at home - only on a larger scale," explains Stephan Kremers, project manager at Vestas.

Simple and time-saving offshore installation

When installing the wind turbines, the pluggable connection of the sea and tower cables allows the individual construction stages of the project partners to be clearly separated from each other. In addition, the very compact SEANEX cast resin joints with a length of 39 cm offer more flexibility in handling during offshore installation. They are solid insulated and thus SF6 gas-free, resistant to salt water and UV radiation as well as floodable and are suitable for different cable types up to a diameter of 800 mm2. In the Seagreen project, they connect the XLPE insulated submarine cables to the switchgear via highly flexible, pre-assembled and pre-tested "dropper cables". When the turbine is installed at sea, the cables are simply plugged into the pre-assembled sleeve, which significantly reduces the offshore installation time. Under load, the gas-free and thus maintenance-free inner cone fittings score points in permanent operation due to their contact safety as well as their high stability due to the separation of mechanical and electrical contact.

As the inventor of inner cone technology, PFISTERER is an offshore pioneer with decades of experience from numerous wind farm projects and a complete product range from 12 to 550 kV for the entire cabling of wind turbines and offshore substations. PFISTERER will deliver the SEANEX fittings for the Seagreen project at the start of construction in 2021 - the 100th year of the company's existence. It is expected that from 2023, Seagreen 1 will supply electricity for around 1.6 million households with a capacity of around 1,075 MW.

About Seagreen

The 1,075 MW Seagreen project, with 114 turbines, is located 27 km off the Angus coast. Seagreen is a £3 billion joint venture between SSE Renewables and Total and will be Scotland's largest source of renewable energy. It makes a significant contribution to Scotland's net zero target, providing enough clean, renewable energy to power 1.6 million homes.