Winds of Change in Offshore Electrical Substations
David Cole
Project Director | Electrical SME | Digital Transformation Strategy | Digital Engineering Innovator
As offshore wind farms have grown in size and moved further offshore, High Voltage Direct Current (HVDC) electrical transmission has, for some developments, become the preferred transmission technology. By reducing transmission losses over long distances, HVDC provides technical and economic advantages over the more common High Voltage Alternating Current (HVAC) used to date. HVDC transmission has already been employed on a number of offshore projects in Germany and its application is set to become more widespread as the sector continues to develop globally and in the United Kingdom with the ongoing Crown Estates Round 3 programme.
From an offshore installation perspective, a key feature of HVDC power transmission is the size of the converter station, which is significantly larger than the equivalent capacity HVAC transformer station. As these stations have tended towards 1 GW in capacity the topside weight, including the equipment it contains, has reached in excess of 10,000 tonnes. This increase in topside weight compounded, in some cases, by a move to deeper waters has led the industry to re-examine suitable platform configurations with the application of some innovative concepts already in service. These include self-installing topsides which are wet towed to site before being jacked up using their own gear. Another concept that has been used is a semi-submersible substructure in a grounded, gravity based application sitting on the seabed.
At KBR, we have extensive North Sea and global experience in fixed and floating offshore structures. In subsequent articles in this series, we have evaluated both fixed and floating substructures and topside structure technologies for offshore HVDC converter stations with respect to cost, environment and water depth. The following structures have been examined;
Fixed Structures
Jacket substructure with lifted topsides
Jacket substructure with self-installing topsides
Jacket substructure with floatover topsides
Floating structures
BARBOX (topsides integrated in fabrication yard)
Semi-submersible (topsides integrated in fabrication yard)
Look out for further articles in the coming weeks.
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6 年I prefer the hydro power scheme with the fixed generator driven by the sea during daytime and by falling overhead lake sea water at night. This overcomes the problem of a becalmed sea during the night and ensures a continuous source of high energy DC power generation.
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6 年Interesting article, and diagram, thank you for sharing it.
Retired EPC Consultant,
6 年Partnering with innovative companies will provide a competitive advantage. Operational Safety is also paramount in any new conceptual design whilst effective lightweight materials will compliment offshore engineering
Oil & Gas | Business Consultant ? Process Engineering SME | Upstream & Midstream ? Natural Gas ? Oilfield Equipment/Packaged Systems | Business Development ? Sales ? Process Engineering
6 年Thanks for sharing.... This is so interesting. We provide parabolic thermal solar concentrators (CSPs) with applications in power generation, enhanced oil recovery, water desalination and waste water treatment.