Substation design for Westermost Rough Offshore Wind Farm

Visualisation of Substation for Westermost Rough Offshore Wind Farm

Visualisation of Substation for Westermost Rough Offshore Wind Farm


Peter Busch Nielsen, Ramboll Oil & Gas

Peter Busch Nielsen

M.Sc., civil and structural eng., Head of Department, Structures, Denmark
T: +45 5161 7238

In the summer of 2011 Ramboll won the detailed design of the offshore substation for DONG Energy's Westermost Rough Offshore Wind Farm in the UK. The wind farm is estimated to make a significant contribution to the UK government goal of installing 33GW of wind production by 2020. The contract with DONG Energy included the conceptual and detailed design of the entire substation, covering both jacket and complete topside design.

Challenging seabed conditions

The Westermost Rough Offshore Wind Farm is located in the UK approximately 8 km off the Yorkshire coast, near the town of Withernsea and is proposed to contain 35-80 turbines of 3-7MW capacity, covering a total area of 35km2.

The bedrock geology across the wind farm site constitutes a significant design challenge for the jacket piles as the soil conditions throughout the surrounding region is composed of Upper Cretaceous Chalk. These soil conditions pose a challenge with respect to driving piles into the seabed. Ramboll has participated in other offshore wind farm projects at nearby sites and our experience from these locations contributed to selecting the right approach for the Westermost Rough offshore substation.

Complete topside and substructure design

The substation is designed for carrying equipment for high-voltage transmission and distribution and other facilities such as diesel generators, batteries and panels for wind turbine control. The platform consists of a steel topside installed on a four legged steel jacket supported by piles. The water depth in the area is approximately 16-26 metres and the water depth at the substation location is approximately 18.0 metres.

The topside was planned with the following main components:

• Two main transformers including coolers
• Nine MV switchgears
• Two auxiliary transformers and two earthing resistors
• Three HV GIS (Gas Insulated Switchgear)
• Control & communication rooms (SCADA)
• LV & utility room
• Diesel power room
• Public room

A significant contribution to UK energy supply

It is estimated that the approximately 210 MW wind farm will be able to provide enough electricity to supply 150,000 British households. The final design is due in the spring of 2012 and the substation is scheduled for installation in 2014.


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