As a consequence of the European Union Renewable Energy Directive, the UK is committed to a target of more than 30% of electricity to be generated from renewable sources by 2020. The transmission reinforcements necessary to allow the EU 2020 renewable target and longer-term energy goals to be achieved in an effective and efficient manner were studied by the Electricity Networks Strategy Group (ENSG) and detailed in their report Our Electricity Transmission Network: A vision for 2020.

It was recognised in the report that due to planning constraints and environmental concerns, traditional methods of enhancing system capacity can be difficult to achieve and consideration was given to employing the latest technology, especially where this would yield additional economic and/or environmental benefits.

One such technology potentially contributing to the achievement of the above aims is Voltage Sourced Converter (VSC) High Voltage Direct Current (HVDC) transmission. Furthermore, VSC HVDC is, in principle, well suited to multi-terminal applications which would allow optimised designs integrating onshore and offshore networks to be achieved and such solutions are under consideration for the GB transmission system. However, while the technology is believed to be achievable, National Grid has not previously implemented VSC HVDC on the GB transmission system and multi-terminal VSC HVDC has not previously been implemented anywhere.

Objectives

The objective of the project is to improve understanding of the problems of VSC HVDC integration into the existing transmission system. The project aims to make progress in three related areas:

• Multi-terminal VSC HVDC operation

• AC/DC VSC HVDC interaction – control

• AC/DC VSC HVDC interaction – detailed model (fast transients).

These areas have been identified as requiring to be addressed as part of the risk managed introduction of the technology onto the transmission system. The project will deliver reports on the results of studies and a documented set of models for use in NGs internal system studies. The work forms an essential step in being able to implement the technology on the transmission system.

It is important that at all stages a close working relationship is maintained between NG engineers and University of Manchester researchers in order to ensure timely transfer of knowledge.