Offshore wind farm with centralised power conversion and DC interconnection

The study of a hypothetical large offshore wind farm based on centralised power conversion and interconnected to the grid using a multiterminal parallel high voltage direct current (HVDC) link is presented. The 300 MW wind farm consists of 60 squirrel-cage based 5 MW generators connected to a common DC bus using ten voltage source converters (VSCs). The transmission system converters provide variable speed generator control, and therefore individual converters are not required for each wind generator, implying savings in wind farm costs. The paper studies the technical and economical benefits of the proposed topology, as well as the selection of the main components. A detailed analysis of the control circuits for both generator and grid facing converters, with respect to primary control functions, is also given. PSCAD/EMTDC simulation of the proposed concept is presented for realistic wind signals. The results confirm operation at an average optimum coefficient of performance at each respective generator group, as well as satisfactory stability even for severe wind speed changes. The proposed concept reduces the costs associated with DC interconnection and may simplify integration of large offshore wind farms at substantial distances.

[1]  Kjell Eriksson.  Operational experience of HVDC light , 2001 .

[2]  O. Carlson,et al.  Integration of wind power by DC-power systems , 2005, 2005 IEEE Russia Power Tech.

[3]  Dragan Jovcic,et al.  Compensation of particle accelerator load using converter-controlled pulse compensator , 2006 .

[4]  V. Akhmatov.  Analysis of Dynamic Behaviour of Electric Power Systems with Large Amount of Wind Power , 2003 .

[5]  D. Jovcic,et al.  Offshore wind farm based on variable frequency mini-grids with multiterminal DC interconnection , 2006 .

[6]  M. Hand,et al.  Wind Turbine Design Cost and Scaling Model , 2006 .

[7]  E. Akpinar,et al.  Statistical analysis of wind energy potential on the basis of the Weibull and Rayleigh distributions for Agin-Elazig, Turkey , 2004 .

[8]  B. T. Ooi,et al.  Optimal Acquisition and Aggregation of Offshore Wind Power by Multiterminal Voltage-Source HVdc , 2002, IEEE Power Engineering Review.

[9]  M. Chinchilla,et al.  Control of permanent-magnet generators applied to variable-speed wind-energy systems connected to the grid , 2006, IEEE Transactions on Energy Conversion.

[10]  Bimal K. Bose,et al.  Modern Power Electronics and AC Drives , 2001 .

[11]  Goran Strbac,et al.  Electrical stability of large, offshore wind farms , 2001 .

[12]  H. Polinder,et al.  General Model for Representing Variable-Speed Wind Turbines in Power System Dynamics Simulations , 2002, IEEE Power Engineering Review.

[13]  Lie Xu,et al.  HVDC transmission for large offshore windfarms , 2001 .