Control system and method for operating a plurality of wind turbines
A method for operating a plurality of wind turbines, in which a first current estimated wind value is derived from operating parameters of a first wind turbine, and in which a second current estimated wind value is derived from operating parameters of a second wind turbine. A prediction model is applied to derive, from the first current estimated wind value and the second current estimated wind value, a wind prediction, applicable to a future time point, for a third wind turbine. The wind prediction is processed in a controller, in order to generate a control signal for the third wind turbine that is effective before the future time point. The invention additionally relates to an associated control system. The loading for particular wind turbines can be reduced in that the wind conditions are predicted for a future time point.
1. A method for operating a plurality of wind turbines, said method comprising:
deriving a first current estimated wind value from operating parameters of a first wind turbine;
deriving a second current estimated wind value from operating parameters of a second wind turbine;
applying a prediction model to said first current estimated wind value and said second current estimated wind value to derive a wind prediction applicable to a future time point for a third wind turbine; and
processing said wind prediction in a controller to generate a control signal for the third wind turbine that is effective before the future time point,
wherein, in the case of a change in a wind direction, said method comprising:
determining in the prediction model a time span between a current time point and the future time point as a sum of a time lag derived from a current wind speed and an additional time that represents a wake of the first wind turbine or a wake of the second wind turbine.
2. The method of claim 1 , comprising:
mapping the wind prediction into a geographical coordinate system by said prediction model.
3. The method of claim 2 , comprising:
defining a location of said third wind turbine by coordinates within the geographical coordinate system.
4. The method of claim 1 , wherein said third wind turbine draws power from the wind, said method comprising:
reducing the power drawn from the wind by the third wind turbine according to the control signal.
5. The method of claim 1 , wherein said method is active only when the current wind speed is above a nominal wind speed or the third wind turbine is being operated at a nominal output.
6. The method of claim 1 , comprising:
deriving, in the prediction model, a speed at which a front line of a wind field is approaching the third wind turbine from the first estimated wind value or from the second estimated wind value.
7. The method of claim 1 , comprising:
including a wake model in the prediction model, said wake model according to which the wake widens as a distance from the first or second wind turbine increases.
8. The method of claim 1 , comprising:
determining a sequence of estimated wind values at differing time points for each wind turbine, and
storing the sequence of estimated wind values for each wind turbine.
9. The method of claim 8 , comprising:
using the estimated wind values determined for a first group of wind turbines to compile a wind prediction, applicable to a future time point, for a second group of wind turbines.
10. The method of claim 9 , comprising:
assigning a wind turbine to the first group or the second group depending upon a wind direction or depending upon the future time point to which the wind prediction is applicable.
11. A control system for a plurality of wind turbines, said control system comprising:
acquisition means which derives a first current estimated wind value from operating parameters of a first wind turbine and derives a second current estimated wind value from operating parameters of a second wind turbine; and
a prediction model which derives a wind prediction, applicable to third wind turbine at a future time point, from the first current estimated wind value and the second current estimated wind value; and
a control system which processes said wind prediction and generates a control signal for the third wind turbine that is effective before the future time point,
wherein, in the case of a change in a wind direction, said control system determines in the prediction model a time span between a current time point and the future time point as a sum of a time laq derived from a current wind speed and an additional time that represents a wake of the first wind turbine or a wake of the second wind turbine.