WIND TURBINE, WIND POWER PLANT AND METHOD FOR CONTROLLING A WIND TURBINE AND A WIND POWER PLANT

Abstract

A wind turbine having a wake control system that is configured so as to control the wind turbine on the basis of wake effects caused at a further wind turbine, wherein the wake control system is configured so as to achieve control based on a turbulence measured value from a turbulence measurement sensor of the further wind turbine. A wind turbine having a turbulence measurement sensor that is configured so as to determine a turbulence measured value, wherein the turbulence measured value is indicative of a turbulence and/or wind shear at the wind turbine, wherein the wind turbine is configured so as to provide the turbulence measured value in order to control the wind turbine and/or a further wind turbine. A wake control system for a wind turbine, but also an improved wind farm and an improved method for controlling a wind turbine and a wind farm.

Claims

1. A wind farm comprising: a wake control system, an upstream wind turbine, a downstream wind turbine, and a sensor configured to obtain a turbulence measurement value at the downstream wind turbine and provide the turbulence measurement value to the wake control system, wherein the wake control system is configured to control the upstream wind turbine based on the turbulence measurement value measured at the downstream wind turbine.

2. The wind farm as claimed in claim 1, wherein the turbulence measured value is indicative of a turbulence or wind shear prevailing at a rotor of the downstream wind turbine.

3. The wind farm as claimed in claim 1, wherein the downstream wind turbine is selected based on at least one of an azimuth position or a determined wind direction.

4. The wind farm as claimed in claim 1, wherein the wake control system is configured to control at least one of an azimuth position, a pitch angle, a generator torque, or a generator power of the upstream wind turbine.

5. The wind farm as claimed in claim 1, wherein the wake control system is configured to control the upstream wind turbine when the turbulence measured value exceeds a first threshold value.

6. The wind farm as claimed in claim 5, wherein the wake control system is configured to increase a pitch angle in response to the turbulence measured value exceeding the first threshold value.

7. The wind farm as claimed in claim 5, wherein the wake control system is configured to record changes in operating parameters and to reverse a last performed change in response to the turbulence measured value exceeding the first threshold value.

8. The wind farm as claimed in claim 7, wherein the wake control system is configured to reverse a last recorded change in an azimuth position.

9. The wind farm as claimed in claim 7, wherein the wake control system is configured to reverse the changes performed over a specific previous period of time or a multiple of previous recorded changes for as long as the turbulence measured value exceeds a second threshold value.

10. The wind farm as claimed in claim 9, wherein the wake control system is configured to change an azimuth position counter to a direction of a last recorded change until the turbulence measured value falls below the determined second threshold value.

11. The wind farm as claimed in claim 1, wherein the sensor includes a bending sensor.

12. The wind farm as claimed in claim 11, wherein the bending sensor is configured to measure bending of a rotor blade in at least one position of the rotor blade.

13. The wind farm as claimed in claim 12, wherein the sensor is configured to measure a horizontal wind shear over a rotor of the downstream wind turbine to obtain the turbulence measured value.

14. The wind farm as claimed in claim 13, wherein the horizontal wind shear is measured as a difference in wind speeds on at least one rotor blade between two different blade positions of the at least one rotor blade.

15. The wind farm as claimed in claim 14, wherein the horizontal wind shear is determined as the difference in the wind speeds at a 3 o'clock position and 9 o'clock position.

16. The wind farm as claimed in claim 13, wherein the sensor is configured to obtain the turbulence measured value by measuring loads acting on at least one rotor blade at different rotor positions.

17. The wind farm as claimed in claim 12, wherein the sensor is configured to measure a wind field over a rotor plane and to derive the turbulence measurement value from the measured wind field.

18. A method comprising: controlling a wind farm, the controlling comprising: measuring a turbulence measured value at a downstream wind turbine, and using a wake control system to control an upstream wind turbine based on the measured turbulence measured value.

19. The method as claimed in claim 18, wherein the turbulence measured value is indicative of a turbulence or wind shear prevailing at a rotor of the downstream wind turbine.

20. The method as claimed in claim 18, wherein using the wake control system to control the upstream wind turbine comprises increasing a pitch angle of one or more rotor blades of the upstream wind turbine in response to the turbulence measured value exceeding a first threshold value.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0044] Further advantages and preferred configurations are described in more detail below with reference to the exemplary embodiments of the accompanying figures, in which:

[0045] FIG. 1 shows a wind turbine, schematically and by way of example,

[0046] FIG. 2 shows a wind farm, schematically and by way of example,

[0047] FIG. 3 shows profiles of a horizontal wind shear as an example of a turbulence measured value, schematically and by way of example, and

[0048] FIG. 4 shows profiles of a vertical wind shear as an example of a turbulence measured value, schematically and by way of example.

DETAILED DESCRIPTION

[0049] FIG. 1 shows a schematic illustration of a wind turbine according to the invention. The wind turbine 100 has a tower 102 and a nacelle 104 on the tower 102. An aerodynamic rotor 106 having three rotor blades 108 and having a spinner 110 is provided on the nacelle 104. During the operation of the wind turbine, the aerodynamic rotor 106 is set in rotational motion by the wind and thereby also rotates an electrodynamic rotor or runner of a generator, which is coupled directly or indirectly to the aerodynamic rotor 106. The electric generator is arranged in the nacelle 104 and generates electrical energy. The pitch angles of the rotor blades 108 may be changed by pitch motors at the rotor blade roots of the respective rotor blades 108.

[0050] In this exemplary embodiment, the wind turbine 100 is controlled by a wake control system 200, which is part of a controller of the wind turbine 100. The wake control system 200 is configured so as to use a turbulence measured value, which is preferably measured at another wind turbine 100, to change operating parameters of the wind turbine 100, in particular an azimuth position of the nacelle 104, a pitch angle of the rotor blades 108 and/or for example a generator torque, such that the turbulence generated by the wake of the wind turbine 100 is reduced as far as possible at the other turbine.

[0051] The wake control system 200 will generally be implemented as part of the control system of the wind turbine 100, which for example also comprises further control systems such as wind tracking, or a control system for complying with maximum loads/noise generation, etc., as is undoubtedly known to those skilled in the art in this field. The wake control system 200 may therefore be integrated into known control systems of wind turbines 100 without any problems.

[0052] The wind turbine 100 furthermore has a turbulence measurement sensor 300 that is configured so as to provide a measured value that describes a variation in the wind situation at the wind turbine 100. By way of example, the measured value may comprise a turbulence intensity, but also a horizontal and/or vertical wind shear. In general, all measured values that indicate that the wind turbine 100 is in the wake of a further wind turbine 100 are conceivable. Examples of such turbulence measurement sensors are LIDAR systems, wherein an optical measurement system that detects the bending of the rotor blades at different rotor blade positions over the rotor rotation are preferably used. From the optically detected bending, precise conclusions are then drawn about the wind conditions prevailing at very different positions on the rotor blade plane.

[0053] The wind turbine 100 of FIG. 1 is accordingly suitable both for responding to wake measurement signals from other wind turbines 100 through the wake control system 200 and furthermore for using the turbulence measurement sensor 300 to in turn provide the wake measurement signal to other wind turbines 100 in order to possibly advantageously adapt the operation through a wake control system that is present there. Other examples of wind turbines 100 may also comprise either the wake control system 200 or the turbulence measurement sensor 300.

[0054] Even though they are shown schematically outside the wind turbine 100 in the drawing, the wake control system 200 and the turbulence measurement sensor 300 will often be implemented at least partially within the wind turbine 100, for example within the nacelle 104.

[0055] FIG. 2 shows a wind farm 112 having, by way of example, three wind turbines 100, 100′, 100″ which may be identical or different. The three wind turbines 100, 100′, 100″ are thus representative of basically any desired number of wind turbines of a wind farm 112. The wind turbines 100, 100′, 100″ provide their power, specifically in particular the generated current, via an electrical farm grid 114. In this case, the respectively generated currents or powers of the individual wind turbines 100, 100′, 100″ are added and a trans-former 116 is usually provided, which steps up the voltage in the farm in order to then feed into the supply grid 120 at the infeed point 118, which is also generally referred to as PCC. FIG. 2 is only a simplified illustration of a wind farm 112, which does not show for example a controller, although a controller is of course present. By way of example, the farm grid 114 may also be designed in another way by virtue of for example a transformer also being present at the output of each wind turbine 100, 100′, 100″, to mention just one other exemplary embodiment.

[0056] For the present application, there should in particular be provision for the farm grid 114 to furthermore be configured so as to transmit turbulence measurement signals from one wind turbine 100, 100′, 100″ to other wind turbines 100, 100′, 100″. A turbulence measured value measured by a turbulence measurement sensor at a wind turbine 100, 100′, 100″ is then used to control a further one of the wind turbines 100, 100′, 100″.

[0057] In the example of FIG. 2, for the sake of simplicity, it is assumed that the arrangement of the wind turbines 100, 100′ and 100″ shown vertically in the drawing corresponds to exactly one direction of the wind 130. The wind turbine 100′ is accordingly exactly in the wake of the wind turbine 100 and the wind turbine 100″ is exactly in the wake of the wind turbine 100′. In the prevailing wind direction in this example, the wind turbine 100′ will accordingly provide turbulence measurement signals to the wind turbine 100, such that a wake control system 200 provided in the wind turbine 100 is able to respond thereto; the same will apply to the wind turbines 100″ and 100′.

[0058] The selection of the wind turbines that provide turbulence measurement signals, that is to say wake measurement signals, to one or more of the other wind turbines may be made based on a programmed selection that is made for example on the basis of the wind direction. As an alternative or in addition, correlations between the turbulence measurement signals and the wind turbines may for example be used to adapt the selection and relationships of those wind turbines that provide signals and those wind turbines that receive and evaluate the associated signals.

[0059] FIG. 3 shows profiles of a horizontal wind shear 300 as an example of a turbulence measured value, schematically and by way of example. The horizontal wind shear is plotted on the vertical axis, which is defined for example as the difference between the wind speed in a 3 o'clock position and a 9 o'clock position of the rotor. Other possibilities for determining the horizontal wind shear are also conceivable, as explained above.

[0060] In the example of FIG. 3, the azimuth position of the rotor is plotted on the horizontal axis, and may be roughly equated with the prevailing wind direction. In an azimuth position 310, the turbine at which the horizontal wind shear was measured is geometrically in the wake of another turbine. It may be seen that, to the left of the azimuth position 310, there is a significant increase with a maximum 312 of the horizontal wind shear. The rise on the left-hand side to the maximum 312 and the fall on the right-hand side of the azimuth position 310 toward the minimum 314 is precisely the influence of the wake corridor of the further turbine. In this example, the scale of the horizontal axis runs from 0 to 360, which corresponds to a full rotation of the nacelle 104 about the tower 102. The position of the upstream turbine at approximately 320 degrees, at which the center of the wake corridor is reached, should of course only be understood as an example.

[0061] When entering the wake corridor, the difference in wind speeds in the horizontal will initially increase, while if the wind turbine is in the center of the wake corridor, no note-worthy wake-induced horizontal wind shear should be expected. Only when the wake corridor is exited again on the other side is there again a clearly measurable horizontal wind shear with the opposing sign.

[0062] In order to determine whether the horizontal wind shear is of natural origin or induced by wake effects, it is advisable to define one or more threshold values 322, 324. The sign of the threshold values 322, 324 indicates the side of the rotor on which the wake effects may be noticed, since a reduced wind speed should be expected there. The threshold values 322, 324 may have the same value or different values in terms of their amount. The threshold values 322, 324 may also be specified as variable over time and in absolute or else relative terms with respect to the prevailing wind.

[0063] FIG. 4 shows profiles of a vertical wind shear 410, 420, 430 as a further example of a turbulence measured value, schematically and by way of example. The relative vertical wind shear is plotted on a vertical axis 440 by way of example as a percentage based on the average value of the wind speed measured over the rotor, while the course of a day from 0 to 24 hours is plotted on a horizontal axis 450 by way of example.

[0064] It may be seen that there are significantly higher relative vertical wind shears 410, 420 and 430 at night 460 than is the case during the day 470. The value of the vertical wind shear may be an indication of the extent to which the turbulence of the wake of a wind turbine is able to propagate at all, that is to say whether or not there are wake effects at the wind turbine on the leeward side.

[0065] The different profiles of the vertical wind shear 410, 420, 430 may be measured for example using different measurement methods, such as LIDAR or else using measuring masts.

[0066] Although vertical and horizontal wind shear have in particular been given as examples of suitable turbulence measured values, the invention is not limited thereto and further turbulence measured values that indicate temporal and/or spatial variations in the wind and are indicative of measurable wake effects are likewise also suitable.