Considerations in design of an offshore network

Abstract

The paper discusses various engineering, regulatory and economic issues associated with offshore networks. It compares AC and HVDC options for simple connections, considers the benefits of coordinated offshore network development and asks whether, in an offshore context, conventions on secure operation that are customary in design and operation of onshore transmission networks are still relevant. It is argued that, except where a loss of infeed issue would be caused for an onshore grid to which an offshore DC network is connected, the lack of demand offshore means that rules can re-evaluated. This leads into a discussion of the need for DC circuit breakers and reliable fault detection and selection on a multi-terminal DC network and options for the control of a DC network. Finally, a number of institutional issues are described including the role of offshore transmission owners and sharing of the costs and benefits of an offshore network.