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USE OF WIND TURBINES FOR FREQUENCY REGULATION IN ISOLATED GRIDS.

Objective

THE RESEARCH DEALS WITH THE STUDY OF AN EDDY CURRENT BRAKE SPEED GOVERNOR FOR WIND TURBINES.

IN HYDRO AND THERMAL TURBINES THE MOTIVE TORQUE DEPENDS ONLY ON THE GEOMETRY OF THE TURBINE, BECAUSE THE HYDRAULIC HEAD AND STEAM ENTHALPY CAN BE ASSUMED CONSTANT FOR RAPID PHENOMENA.
ON THE CONTRARY IN WIND TURBINES THE MOTIVE TORQUE DEPENDS MOSTLY ON WIND SPEED. IF THE SPEED GOVERNOR ACTS ON TURBINE GEOMETRY (THAT IS THE PITCH ANGLE), THE FREQUENCY CONTROL OF ISOLATED GRIDS IS NOT POSSIBLE BECAUSE THE PITCH CONTROL IS TOO SLOW TO COPE WITH RAPID CHANGES IN ELECTRICITY DEMAND AND WIND SPEED.
WITH AN EDDY CURRENT BRAKE COAXIAL TO THE TURBINE SHAFT, THE SPEED GOVERNOR MODULATES THE RESISTANT TORQUE, AND COMPENSATES THE TORQUE UNBALANCE.
THIS CONTROL PHILOSOPHY ACHIEVES THE FOLLOWING RESULTS :
- THE GEOMETRY VARIATION OF THE ROTOR IS NO LONGER CALLED UPON TO REGULATE THE SPEED;
- THE ROTOR CAN BE DESIGNED WITHOUT THE CONSTRAINT OF A RAPID GEOMETRY VARIATION. IN PARTICULAR CASES FIXED GEOMETRY ROTORS CAN BE USED;
- THE WIND TURBINE CAN TAKE AN ACTIVE PART IN THE CONTROL OF THE FREQUENCY OF SMALL OR ISOLATED GRIDS, IN THE SAME MANNER AS DIESEL GENERATORS OR TURBOGENERATORS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Riva Calzoni SpA
Address
Via Stendhal 34
20144 Brunico
Italy