SS - Implications of Subsea Processing Power distribution on Field architecture : Electrical transmission and distribution architectures for subsea processing systems

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Abstract Work is currently ongoing in the offshore oil & gas industry to develop subsea processing systems supplying multiple electrical consumers, over long step-outs and in deep waters. To meet the technical challenges of these developments, new subsea electrical power transmission and distribution architectures have to be developed. This paper gives an overview of possible electrical power transmission and distribution architectures. It addresses the main technical challenges and present limitations, describes the system approach and gives an operator's viewpoint as to the way forward. Introduction With today's fields fast becoming depleted and discoveries of easy-to-produce offshore oil & gas resources ever fewer, subsea processing equipment is the focus of an extensive development drive. The results are especially attractive for remote fields, deep waters and tough topside environments such as arctic locations. As subsea equipment evolves to become increasingly sophisticated and power-intensive (pumps, compressors, processing, and flow assurance systems), there is a growing need for ultra-reliable electrical transmission and distribution systems to power the equipment over long step-outs. Like subsea applications, electrical architectures are site-dependent and a suitable electrical transmission and distribution architecture has to be defined based on the electrical power needed, the water depth and the tie-back length for each specific oil and gas field development. This paper examines the ins and outs of using AC and DC transmission for subsea applications, overviews the options of electrical power transmission architectures open to the operator depending on the type of oil and gas field to be developed, and addresses the main technical challenges and present limitations. It focuses exclusively on power-intensive subsea applications, and the challenges of transferring large quantities of electrical power (> 1MW) over long distances.