METHOD FOR DETERMINING SHADOW FLICKER FROM A WIND TURBINE SYSTEM

Abstract

The invention relates to a method for controlling a wind turbine system, more particular for a method for determining shadow flicker at a location and identifying a wind turbine in a wind park with a plurality of wind turbines causing the shadow flicker. A remote detector located at or near the location is determining the presence of shadow flicker and generating flicker data representative of the shadow flicker. A target wind turbine potentially causing a shadow at the location is identified based on the turbine position and the position of the sun. Operational data from the target wind turbine is obtained and it is verified whether the target wind turbine generates the shadow flicker by comparing the flicker data and the operational data.

Claims

1. A method for determining shadow flicker at a location and identifying a wind turbine in a wind park with a plurality of wind turbines causing the shadow flicker, the method comprising: determining a presence of shadow flicker at the location; generating flicker data representative of the shadow flicker; identifying at least one target wind turbine potentially causing shadow flicker at the location based on a position of the at least one target wind turbine and a position of the sun; generating operational data from the at least one target wind turbine; and verifying that the shadow flicker is generated by the at least one target wind turbine by comparing the flicker data and the operational data.

2. The method of claim 1, pausing operation of the at least one target wind turbine verified to cause the shadow flicker.

3. The method of claim 1, wherein the flicker data comprises detected oscillations in the light intensity at the location.

4. The method of claim 1, wherein each wind turbine comprises a rotor, and the operational data comprises a rotor speed of a respective rotor of at least the at least one target wind turbine.

5. The method of claim 1, wherein each wind turbine comprises a rotor, and the operational data comprises an angular position of a blade of the rotor of the at least one target wind turbine.

6. The method of claim 5, wherein, the verifying involves determining, if the oscillations in the light intensity and the angular position of the blades are synchronic.

7. The method of claim 1, wherein the at least one target wind turbine verified to cause shadow flicker resumes normal operation when determined that the at least one target wind turbine will no longer cause shadow flicker at the location.

8. The method of claim 1, wherein the presence of shadow flicker at the residence is determined by a remote detector located at the location.

9. The method of claim 7, wherein the remote detector is a portable device comprising at least a light intensity sensor and a GPS locator.

10. The method of claim 8, wherein the portable device is a mobile phone.

11. The method of claim 8, further comprising: upon determining determining that the portable device is no longer present at the location, resuming normal operation of the target wind turbine.

12. A detector system to determine shadow flicker at a location in the vicinity of a wind park comprising a plurality of wind turbines; wherein the detector system, comprises: a remote detector configured to process data to generate flicker data representative of the shadow flicker at the location; and a wind power plant control system communicatively coupled to the remote sensor and configured to: identify at least one target wind turbine potentially causing a shadow at the location based on a position of the at least one target wind turbine and a position of the sun, generate operational data of the at least one target wind turbine, and verify that the shadow flicker is generated by the at least one target wind turbine by comparing the flicker data and the operational data.

13. The detector system of claim 13, pausing operation of the at least one target wind turbine verified to cause the shadow flicker.

14. The detector system of claim 13, wherein the flicker data comprises detected oscillations in the light intensity at the location.

15. The detector system of claim 13, wherein each wind turbine comprises a rotor, and the operational data comprises a rotor speed of a respective rotor of at least the at least one target wind turbine.

16. A computer program product comprising software code adapted to control a wind turbine system when executed on a data processing system, the computer program product being adapted to perform an operation for determining shadow flicker caused by at least one wind turbine of a plurality of wind turbines, the operation comprising: determining a presence of shadow flicker at a location; generating flicker data representative of the shadow flicker; identifying at least one target wind turbine, of the plurality of wind turbines, potentially causing shadow flicker at the location based on a position of the at least one target wind turbine and a position of the sun; generating operational data from the at least one target wind turbine; and verifying that the shadow flicker is generated by the at least one target wind turbine by comparing the flicker data and the operational data.

17. The computer program product of claim 16, pausing operation of the at least one target wind turbine verified to cause the shadow flicker.

18. The computer program product of claim 16, wherein the flicker data comprises detected oscillations in the light intensity at the location.

19. The computer program product of claim 16, wherein each wind turbine comprises a rotor, and the operational data comprises a rotor speed of a respective rotor of at least the at least one target wind turbine.

20. The computer program product of claim 16, wherein each wind turbine comprises a rotor, and the operational data comprises an angular position of a blade of the rotor of the at least one target wind turbine.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0051] Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which

[0052] FIG. 1 illustrates a wind turbine,

[0053] FIG. 2 illustrates a wind turbine in a wind park causing shadow flicker at a residence,

[0054] FIG. 3 illustrates a wind power plant control system according to an embodiment of the invention,

[0055] FIG. 4 illustrates wind turbines configured as multi-rotor wind turbines.

DETAILED DESCRIPTION OF AN EMBODIMENT

[0056] FIG. 1 shows a wind turbine 100 (also commonly referred to as a wind turbine generator, WTG) comprising a tower 101 and a rotor 102 with at least one rotor blade 103. Typically, three blades are used, but a different number of blades can 15 also be used. The blades 103 are connected with the hub 105, which is arranged to rotate with the blades. The rotor is connected to a nacelle 104, which is mounted on top of the tower 101 and being adapted to drive a generator situated inside the nacelle 104 via a drive train. The rotor 102 is rotatable by action of the wind. The wind induced rotational energy of the rotor blades 103 is transferred via a shaft to 20 the generator. Thus, the wind turbine 100 is capable of converting kinetic energy of the wind into mechanical energy by means of the rotor blades and, subsequently, into electric power by means of the generator.

[0057] FIG. 2 shows a wind park 201 comprising a plurality of wind turbines 100. When the sun 202 is shining the wind turbines 100 cause shadows 203, which may, when the sun 202 is in a certain position, hit a residence 204. When the rotor 102 is rotating, the shadow 203 may cause shadow flicker, causing nuisance to a person staying at the residence 204. At, or near, the residence 204, a remote detector 205 is located. The remote detector 205 is adapted to determine changes in light intensity. The remote detector 205 may for example be able to detect light oscillation at a frequency similar to the frequency expected from a specific wind turbine 100 in the wind park 201. The data generated by the remote detector 205 can then be analysed to detect the presence of shadow flicker and flicker data can be generated. Flicker data may comprise information of the frequency of the flicker. It could also or alternatively comprise one of the following; position of the residence, presence of shadow flicker, amplitude of the light intensities, one or more of height, polar angle, and azimuthal angle of the detector.

[0058] When shadow flicker at a residence 204 is determined, target wind turbines 100, which may cause shadow flicker at the residence 204, are identified from the position of the sun 202 and from the position of each wind turbine 100 in the wind park 201. A wind park 201 comprises a number of wind turbines 100, and it is possible that more than one wind turbine 100 is causing shadow flicker at the residence 204. Further, it can be difficult and includes some uncertainty, which wind turbines 100 are actually causing shadow flicker at the residence 204. Therefore, a verification process to verify which wind turbine 100 is actually causing the shadow flicker may be needed.

[0059] To perform the verification, flicker data 301 is generated and transmitted to a wind power plant control system 206. The flicker data 301 may comprise light intensity and the frequency of the oscillations of the light intensity. The wind turbine 100 generates operational data 306 and transmit the operational data 306 to the wind power plant control system 206. The operational data 306 may comprise rotation speed of the wind turbine 100 and the position of the rotor blades 103. The position of the rotor blades 103 may be detected by registering the time, when a rotor blade 103 is passing the tower 101. The wind power plant control system 206 analyses and compares the flicker data 301 and the operational data 306 to verify the wind turbine 100 causing the shadow 203.

[0060] The remote detector 205 may be a stationary detector, for instance placed at the residence 204. The remote detector 205 may also be a portable device for instance a mobile phone carried be a person staying at the residence 204. The person staying at the residence 204 then may place the portable device in a position, where it may determine shadow flicker. The portable device may comprise a camera, using the camera to record the shadow flicker. The portable device may determine shadow flicker only at the exact location the person is, and therefore there is no need for pausing the target wind turbine 100, if the shadow flicker is not present, where the person is, even though shadow flicker may be present elsewhere at the residence.

[0061] FIG. 3 shows a diagram illustrating a possible implementation of the functionality of the invention. Flicker data 301 is received and it is determined whether the received flicker data 301 comprises information that shadow flicker occur 302. The flicker data may be generated based on data recorded by a sensor at, or near, the residence. If shadow flicker occur, then based on positioning data and sun data 303 the target wind turbine(s) 100 is/are identified 304 as possibly causing shadow flicker at the residence 204 by using the position of the sun 202 and the position of the wind turbines. For target wind turbines 100 identified 305, operational data 306 from each target wind turbine 100 is used to checks whether the oscillations in the flicker data 301 and the rotation speed of the target wind turbine 100 have identical frequencies 307. If they have identical frequencies, then it is checked whether the oscillations in the flicker data 301 and the position of the rotor blades 103 in the operational data are synchronous 308. If they are synchronous, then it is verified that the target wind turbine 100 is causing the shadow flicker 309 on the residence, and the target wind turbine 100 therefore is paused 310. Otherwise, if it is not verified, then the target wind turbine 100 do not cause shadow flicker 311, and the method do not pause the wind turbine 312.

[0062] The synchronous test may be done by finding the time difference between the time registered in the operational data 306 for a rotor blade 103 passing the tower 101, and the time registered in the flicker data 301, where the light intensity reaches a minimum intensity. The time difference is then compared to the time it will take for the rotor blade 103 to move from the position, where it is directly between the sun 202 and the remote detector 205, to the position passing the tower 101. If the time differences match the synchronous test, then the target wind turbine 100 may by paused.

[0063] When the target wind turbine 100 is paused, the remote detector 205 continues to detect the intensity of the sun light. If the sun light disappears, then the remote detector 205 may transmit a message and the target wind turbine 100 can resume normal operation. If the remote detector is portable, for instance a mobile phone, it can be detected, when the portable remote detector is moved away from the residence, and the target wind turbine 100 can resume normal operation. In addition, the shadow caused by the target wind turbine 100 may be continuously monitored at the location of the residence 204, or the position of the shadow can be calculated from the movement of the sun 202 and when the shadow 203 moves away from the residence 204, the normal operation of the target wind turbine 100 is resumed.

[0064] FIG. 4 shows alternative wind turbines 100 configured as multi-rotor wind turbines. Multi-rotor wind turbines comprises a plurality of nacelles 104. The nacelles 104 can be supported, as illustrated in the upper drawing, via a tower 101 and support arms 106 extending outwardly from the tower 101 so that the nacelles are placed away from the tower and on opposite sides of the tower. Alternatively, as illustrated in the lower drawing, the nacelles 104 can be supported by angled towers 101 extending from a foundation 130, e.g. a ground or floating foundation, so that two or more nacelles 104 are sufficiently separated from each other at a given height. Embodiments of the present invention may also be used with multi-rotor wind turbines. The method can be used to not only identify and verify, if a specific multi wind turbine is causing shadow flicker at a residence, but also be used to determine the specific rotor or rotors causing the shadow flicker. In this way in can be ensured that only the rotors causing the shadow flicker are paused.

[0065] The invention can be implemented by means of hardware, software, firmware or any combination of these. The invention or some of the features thereof can also be implemented as software running on one or more data processors and/or digital signal processors.

[0066] The individual elements of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way, such as in a single unit, in a plurality of units or as part of separate functional units. The invention may be implemented in a single unit, or be both physically and functionally distributed between different units and processors.

[0067] Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is to be interpreted in the light of the accompanying claim set. In the context of the claims, the terms “comprising” or “comprises” do not exclude other possible elements or steps. Also, the mentioning of references such as “a” or “an” etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.