Case Studies

The University of Manchester, in collaboration with Siemens Transmission and Distribution, is undertaking a study funded by the Northern Wind Innovation Programme to investigate new energy networks for offshore wind farms. The work builds on the considerable experience of the University in electrical power engineering and is part of the University's 'Manchester Energy Initiative'. The focus of the work is the connection of nextgeneration offshore wind farms into the UK transmission system.

The use of local, renewable energy will play an important future role in the UK. Its goal is to achieve long-term energy security and to contribute to a low-carbon economy. Wind energy will play a key part of the energy supply mix to achieve this. However on-shore wind farms have a number of problems. In the latest planning round for windfarms (Round 3), the sites considered have been far-offshore and very high power. State-of-the-art wind turbines are each rated 4.5MW or more (fourand- a-half million-watts, enough to power 1500 homes at full-power). Some of the larger wind-farms planned offshore consist of perhaps a thousand such turbines.

The very large powers under consideration must be brought to shore. However unlike the first offshore sites, which were very close to the coast, some of the larger wind-farms are considerably further away. At distances of more than about 50km-80km offshore, DC transmission becomes the preferred connection system over the more usual AC. The connection of these large wind-farms to shore requires high-voltage DC (HVDC) transmission, and because of the relatively compact size of offshore platforms, this must use the relatively new concept of voltage-source converter (VSC) HVDC. Only a few proof-of-concept installations have been built world-wide and no finalised system concept has yet been agreed upon. The work at Manchester will aim to derive system concepts and connection strategies.

Mervyn Sara
Technology Manager

Siemens Transmission & Distribution Ltd
Sir William Siemens House
Princess Road
Manchester
M20 2UR, UK

Tel: +44 (0)161 446 5103
Email: mervyn.sara@siemens.com
Website: www.siemens.co.uk