阅读说明：本技术 风力发电设备及其设计和操作方法以及风力发电场 (Wind power plant, method for designing and operating a wind power plant, and wind farm ) 是由 拉尔夫·梅辛 于 2021-05-14 设计创作，主要内容包括：本公开涉及一种用于设计和操作用于从风产生电力的风力发电设备(100)的方法,其中,该风力发电设备(100)具有空气动力转子(106),该空气动力转子具有叶片桨距角可以被调节的转子叶片(108),其中,转子叶片(108)在转子叶片根部(114)与转子叶片梢部(116)之间被多个涡流发生器(118)占据,其特征在于,涡流发生器(118)在相应的转子叶片(108)的纵向方向上所占据到的半径位置(r/R)是根据风力发电设备(100)的位置处的待设定的声功率级来确定的。本公开还涉及风力发电设备(100)的转子叶片(108)、涉及相关的风力发电设备(100)以及涉及风力发电场。(The present disclosure relates to a method for designing and operating a wind power plant (100) for generating electrical power from wind, wherein the wind power plant (100) has an aerodynamic rotor (106) with a rotor blade (108) whose blade pitch angle can be adjusted, wherein the rotor blade (108) is occupied between a rotor blade root (114) and a rotor blade tip (116) by a plurality of vortex generators (118), characterized in that the radial position (R/R) occupied by a vortex generator (118) in the longitudinal direction of the respective rotor blade (108) is determined depending on the acoustic power level to be set at the position of the wind power plant (100). The disclosure also relates to a rotor blade (108) of a wind power plant (100), to a related wind power plant (100) and to a wind farm.)

1. A method for designing and operating a wind power plant (100), the wind power plant (100) being intended for generating electric power from wind, wherein the wind power plant (100) has an aerodynamic rotor (106), the aerodynamic rotor (106) having a rotor blade (108) with a blade pitch angle (γ) that can be adjusted, wherein the rotor blade (108) is occupied in a longitudinal direction between a rotor blade root (114) and a rotor blade tip (116) at a radial position by a plurality of vortex generators (118), characterized in that the radial position (R/R) that the vortex generators (118) occupy in the longitudinal direction of the respective rotor blade (108) is determined depending on the acoustic power level to be set at the position of the wind power plant (100).

2. A method according to claim 1, wherein the blade pitch angle (γ) of the rotor blade (108) with which the wind power plant (100) is operated is additionally determined in dependence of the acoustic power level to be set at the location of the wind power plant (100).

3. A method according to claim 2, characterized in that the wind power plant (100) is operated in a noise reduction operation mode at a reduced rated rotor speed compared to an optimized power operation mode depending on the sound power level to be set at the location of the wind power plant (100).

4. A method according to claim 3, characterized in that the determination of the radial position (R/R) at which the vortex generator (118) terminates and the blade pitch angle (γ) of the rotor blade (108) with which the wind power plant (100) is operated is performed in dependence of the acoustic power level to be set, such that an expected flow separation due to the reduced rated rotor speed is prevented and an expected power loss is minimized.

5. A method according to claim 3 or 4, characterized in that the occupancy of the vortex generator (118) in the longitudinal direction of the respective rotor blade (108) proceeds to a radial position (R/R) determined in dependence of the reduced rated rotor speed.

6. A method according to one of claims 3 to 5, characterized in that the determination of the radial position (R/R) occupied by the vortex generator (118) in the longitudinal direction of the respective rotor blade (108) is performed in dependence of the acoustic power level to be set such that an increase of the blade pitch angle (γ) is minimized, which is necessary in case of a relatively low acoustic power level to be set and which is caused by a necessary reduction of the rated rotor speed.

7. A method according to one of the claims 3 to 6, characterized in that the determination of the radial position (R/R) at which the vortex generator (118) terminates and the blade pitch angle (γ) of the rotor blade (108) with which the wind power plant (100) is operated is performed in accordance with the acoustic power level to be set such that during hybrid operation comprising operating periods in a power optimizing operating mode and a noise reducing operating mode, production losses in the power optimizing operating mode are compensated at least by production gains in a certain period in the noise reducing operating mode.

8. Method according to one of the preceding claims, characterized in that the blade pitch angle (γ) is set according to the radial position (R/R) determined for the occupancy of the vortex generator (118).

9. Method according to one of the preceding claims, characterized in that the occupancy of the rotor blades (108) by the vortex generators (118) is performed taking into account a specific operational management, in particular a specific power rating with which the wind power plant (100) is operated at one location.

10. Method according to one of the preceding claims, characterized in that a plurality of blade setting characteristics (602, 604) are stored and one blade setting characteristic (604) is selected from the stored blade setting characteristics (602, 604) depending on the radial position (R/R) determined for the occupancy of the vortex generator (118) and the one blade setting characteristic (604) is used for setting the blade pitch angle (γ).

11. Method according to one of the preceding claims, wherein the radial position (R/R) occupied by the vortex generator (118) in the longitudinal direction of the respective rotor blade (108) is determined according to the proportion of noise reduction operation mode at the location of the wind power plant (100).

12. Method according to claim 11, wherein the operational management of the wind power plant, in particular the setting of the blade pitch angle (γ), is additionally determined according to the proportion of the noise reduction operation mode at the location of the wind power plant (100).

13. A rotor blade (108) extending from a rotor blade root (114) to a rotor blade tip (116), the rotor blade (108) comprising a suction side, a pressure side and a plurality of vortex generators (118), wherein the plurality of vortex generators (118) are arranged at least on the suction side between the rotor blade root (114) and the rotor blade tip (116), wherein the vortex generators (118) are arranged to a radial position (R/R) in the longitudinal direction of the respective rotor blade (108) depending on a position-specific acoustic power level to be set.

14. The rotor blade (108) according to claim 13, wherein the arrangement of the vortex generators (118) to the radial position (R/R) of the rotor blade (108) in the direction of the rotor blade tip (116) starting from the rotor blade root (114) is performed such that during a noise reduction operation with a reduced rated rotor speed compared to a power optimization operation, an expected flow separation due to the reduced rated rotor speed is prevented and an expected power loss is minimized by setting a blade pitch angle (γ) of the rotor blade (108) to match the arrangement of the vortex generators (118).

15. A wind power plant (100), the wind power plant (100) comprising an aerodynamic rotor (106) and a control system (200), the aerodynamic rotor (106) having rotor blades (108) whose blade pitch angle (γ) can be adjusted, wherein the rotor (106) is operable in a respective operating mode at a respective settable nominal rotor speed, characterized in that the control system (200) is designed to operate the wind power plant (100) according to a method according to at least one of claims 1 to 12.

16. Wind power plant (100) according to claim 15, characterized in that the rotor (106) has at least one rotor blade (108) according to any of the preceding claims 13 and 14.

17. A wind farm comprising a plurality of wind power plants (100) according to claim 15 or 16.

Technical Field

The present disclosure relates to a method for designing and operating a wind power plant for generating electrical power from wind, wherein the wind power plant has an aerodynamic rotor with rotor blades whose blade angle can be adjusted, wherein the rotor blades are occupied by a plurality of vortex generators between a rotor blade root and a rotor blade tip. Furthermore, the present disclosure relates to a rotor blade of a wind power plant, to a wind power plant and to a wind farm.

Background

In order to influence the aerodynamic properties of the rotor blade, it is known to provide vortex generators on the cross-sectional profile of the rotor blade, which vortex generators comprise a plurality of vortex elements which run in a perpendicular manner with respect to the surface. Vortex generators are used to create a turbulent airflow over the surface of the rotor blade in a localized area to achieve an increase in the resistance to flow separation. For this reason, the vortex generators swirl the flow close to the surface of the rotor blade, as a result of which the momentum exchange between the flow layer close to the surface and the flow layer remote from the surface is greatly increased and the flow velocity in the boundary layer close to the surface is increased.

In the context of cost-optimized production, the rotor blades are usually equipped with vortex generators in a standardized manner, i.e. the vortex generators occupy the rotor blade in the same manner for each position.

Wind power plants are subject to various environmental conditions depending on their location; in particular, the characteristics of the wind farm to which the wind power plant is exposed during diurnal and seasonal variations may vary greatly. Wind farms are characterized by a large number of parameters. The most important wind field parameters are average wind speed, turbulence, vertical and horizontal shear, variation in height of the wind direction, oblique incident flow and air density.

The wind power plant may also be subjected to different general conditions depending on its location. For example, these general conditions may be regulations such as an allowable noise level distance with respect to ambient noise or an acoustic power level generated by the wind power plant during operation at a certain distance from the wind power plant and which must not be exceeded. For example, in france, the sound power level requirement during part load operation of the wind power plant is 5 to 6 decibels with respect to ambient noise.

In order to reduce the sound power level, the wind power plant is usually operated at a reduced rated rotor speed, i.e. at a reduced part-load speed and a reduced rated load speed, in the noise reduction mode of operation compared to the power optimization mode of operation. In order to avoid the threat of flow separation, which would otherwise cause large power losses, in particular of the central region of the rotor blade, the blade pitch angle is increased from a defined power, which is often also referred to as pitch angle.

DE102018127804a1 relates to a method for controlling a wind turbine. The method comprises measuring noise emissions by means of at least one pressure sensor attached to the rotor blade; identifying a characteristic aero-acoustic sound for at least one flow separation based on the noise emission; and controlling one or more components of the wind turbine in an open or closed loop manner based on the identification of the characteristic aero-acoustic sounds of the flow separation.

DE102015008813a1 relates to a method for operating a wind power plant having at least one rotor blade which is mounted on a rotor and at least one vortex generator which is arranged on the rotor blade outer skin and is displaced during operation.

DE102013202881a1 relates to a method for calculating a trailing edge generated for a rotor blade of an aerodynamic rotor of a wind power plant, wherein the rotor blade has a radial position relative to the rotor, the rotor blade has a local blade profile which is a function of the radial position relative to the rotor, and the trailing edge comprises a sawtooth-shaped profile with a plurality of peaks, wherein each peak has a peak height and a peak width, and the peak height and/or the peak width is calculated as a function of its radial position and/or as a function of its local blade profile of its radial position.

US2017/0314530a1 relates to a wind turbine blade assembly comprising a rotor blade having an outer surface defining a pressure side, a suction side, a leading edge and a trailing edge, the outer surface each extending between a blade tip and a blade root. The rotor blade also defines a span chord. The blade assembly also includes a plurality of micro boundary layer actuators positioned on a surface of the pressure side of the rotor blade. The plurality of micro boundary layer actuators extend one of above or below a neutral plane of the rotor blade. The micro boundary layer actuators are shaped in a chordwise manner and positioned to delay boundary layer separation at a small angle of attack. A wind turbine including the blade assembly is also disclosed.

US2014/0093382a1 relates to a wind turbine rotor blade comprising a root portion, an airfoil portion, a thickened region extending outwardly from an inner hub end of the blade into the airfoil portion of the blade; and an airflow correction device disposed on the pressure side of the blade over at least a portion of the thickened region. The airflow correction device comprises a spoiler for increasing the blade lift and a vortex generator arranged between the leading edge and the trailing edge and enabling an attached airflow to be maintained between the vortex generator and the spoiler. A wind turbine having at least one such rotor blade is disclosed. An airflow correction device for correcting an airflow at a pressure side of a wind turbine rotor blade for a region of the blade having a thickened area is also disclosed.

US2012/0189444a1 relates to a wind turbine blade comprising one or more turbulence generating strips, wherein the strips are placed on the surface of the blade. The blade is characterized in that at least one junction area of the turbulence-generating strip and the surface of the blade is completely or partially covered by the sealing means. The invention also relates to a pitch controlled wind turbine comprising at least two pitch controlled wind turbine blades and pitch control means for pitching the blades. The pitch controlled wind turbine is characterized in that the blade comprises one or more turbulence generating strips, wherein the turbulence generating strips and at least one junction area of the surface of the blade are completely or partially covered by sealing means.

Disclosure of Invention

On this background, it is an object of the present disclosure to develop a method for designing and operating a wind power plant, which method is characterized by a more efficient operation of the wind power plant, and to specify a rotor blade, a wind power plant and a wind farm which allow for a more efficient operation.

According to one aspect, the object on which the disclosure is based is achieved by a method for designing and operating a wind power plant having the features according to the first aspect of the invention. One aspect of the invention proposes a method for designing and operating a wind power plant for generating electric power from wind, wherein the wind power plant has an aerodynamic rotor with rotor blades whose blade pitch angle can be adjusted, wherein the rotor blades are occupied in the longitudinal direction between a rotor blade root and a rotor blade tip at a radial position by a plurality of vortex generators. The object of improving the operating efficiency of a wind power plant is achieved by: the radial position which the vortex generator occupies in the longitudinal direction of the respective rotor blade is determined as a function of the sound power level to be set at the location of the wind power plant.

The sound power level to be set is selected such that the wind power plant meets the sound power level requirements at the location of the wind power plant. In order to prevent flow separation, during operation of the wind power plant, occupying the rotor blades to a radial position located further externally in the longitudinal direction of the respective rotor blade allows providing a smaller blade pitch angle. Thus, the wind power plant may be operated in the noise reduction mode of operation at a reduced rated rotor speed and at a higher power factor than in the power optimization mode of operation. This makes it possible to increase the annual energy production of the wind power plant. The annual energy production increase may be in the range of a few percent, for example 2% to 4%.

According to the present disclosure, it is therefore proposed to provide a regulated occupancy of the vortex generators on the respective rotor blade at a position having a relatively low allowed acoustic power level, to prevent the occurrence of flow separation due to a relatively low rated rotor speed in a noise reduction mode of operation compared to the previous occupancy of the rotor blade by the vortex generators independently of position. The vortex generators may increase the maximum angle of attack at which stall occurs. The position-based, i.e. non-standardized, occupation of the rotor blades by the vortex generators may lead to an increase in production, which overall may greatly compensate for the costs saved in terms of production independently of the position occupation.

Operating the wind power plant at a relatively low rated rotor speed results in a relatively low acoustic power level of the wind power plant. However, a relatively low rated rotor speed also results in an increase of the local angle of attack along the rotor blade. In order to limit the angle of attack and avoid flow separation on the rotor blade, the blade pitch angle is adjusted. Adjusting the blade pitch angle, in particular setting a relatively large blade pitch angle, results in significant production losses. The angle of attack at the transition between the region of the rotor blade with vortex generators and the region of the rotor blade without vortex generators is often crucial for setting the blade pitch angle. In many cases, the risk of flow separation is greater in the region facing the hub than in the outer blades, and there is a production potential in the outer blades. Extending the occupancy of vortex generators to the blade tip while adjusting the blade pitch angle management, in particular reducing the blade pitch angle, may improve the Annual Energy Production (AEP).

In the method, preferably the blade pitch angle of the rotor blade with which the wind power plant is operated is additionally preferably determined depending on the acoustic power level to be set at the location of the wind power plant. The method may provide that the blade pitch angle of the rotor blade with which the wind power plant is operated and the radial position occupied by the vortex generator in the longitudinal direction of the respective rotor blade are determined depending on the acoustic power level to be set at the position of the wind power plant. This may match the occupancy of the rotor blades and the setting of the blade pitch angle to each other in order to increase the annual energy production while complying with the acoustic power level requirements.

In the noise reduction mode of operation, the wind power plant may be operated at a reduced rated rotor speed compared to the power optimization mode of operation depending on the sound power level to be set at the location of the wind power plant. This may increase annual energy production while meeting acoustic power level requirements.

Decreasing the pitch angle of the blade may in turn result in an increased acoustic power level. The nominal rotor speed can be reduced such that the acoustic power level to be set is achieved taking into account the reduced blade pitch angle and the occupancy of the rotor blade by the vortex generators. The optimum combination of blade pitch angle and speed can be achieved iteratively here, or can be achieved by optimized methods and can reach a plateau, under the boundary conditions of the acoustic power level to be set.

The method may also, for example, determine that for a particular rotor blade which reaches a predetermined sound power level to be set, it is advantageous not to have vortex generators and that the occupancy of vortex generators is only introduced if the sound power level to be set falls below the predetermined sound power level.

The occupancy of the vortex generators may start immediately at the rotor blade root or at a distance from the rotor blade root in the longitudinal direction. It is essential to the success of the present disclosure that the occupation ends at a radial position determined according to the present disclosure which depends on the sound power level to be set. Also a continuous or constant occupancy of the vortex generators does not have to be performed, that is to say an interruption of the occupancy is also possible.

In the case of passive elements in the form of vortex generators for influencing the flow, "take up" is to be understood as meaning in particular the fitting of such elements to or on the rotor blade. In the case of active elements for influencing the flow, "take up" can be understood to mean in particular the activation or deactivation of such elements, but also the fitting of the elements to or on the rotor blade. Active elements for influencing the flow include slots or openings for sucking in and/or blowing out air, controllable baffles, etc. For example, vortex generators in the form of plasma generators may also be used to generate turbulence.

Particularly preferably, a combination of active and passive elements for influencing the flow can be used as vortex generators. In this case, therefore, passive vortex generators can be used, for example, in the inner region close to the rotor blade root, while active vortex generators can be used in the more outer regions. The radial position of the rotor blade occupied by the vortex generator can therefore also be varied during ongoing operation by controlling the active elements for influencing the flow and can be matched in particular to environmental conditions, for example the air density or modified general conditions, in particular modified acoustic power level requirements. Meanwhile, the proportion of the active vortex generators is relatively small, so that the design complexity is lower compared with that of a special active vortex generator.

The air density is not constant but varies over time. Therefore, an average value, such as an annual average value of air density or other minimum annual air density, is preferably used as the value of air density. Alternatively or additionally, the geographical height of the location may be included, which has an effect on the air density, as is well known. The air density is then preferably calculated from the geographical altitude and, for example, the average temperature of the location.

The sound power level requirements determining the sound power level to be set that must not be exceeded may also vary over time at the location. For example, different sound power level requirements may apply at different times, such as during the night and day or at specific rest times.

The radial position represents a position on the rotor blade along the longitudinal axis of the rotor blade as a radius of the respective position relative to the outer radius of the rotor, or the radial position represents the rotor blade length. Two reference variables other than radius and rotor blade length differ by half the rotor blade hub diameter, which may need to be subtracted.

Thus, the relevant position on the rotor blade as radial position may be indicated by a value in the range from 0 (zero) to 1 (one). The reason for using radii to describe the position along the rotor blade is that the rotor blade is intended to be mounted on a rotor of a wind power plant to meet its intended use. Thus, the rotor blade is always permanently associated with the rotor, and therefore the radius is used as a reference variable. The radial position preferably has a value 0 (zero) at the center point of the rotor, i.e. on the rotor rotation axis. The radial position preferably has a value of 1 (one) at the blade tip, which characterizes the outermost point of the rotor.

The radial position at which the vortex generator terminates and the blade pitch angle of the rotor blade with which the wind power plant operates may preferably be determined in dependence of the sound power level to be set, such that an expected flow separation due to a reduced rated rotor speed is prevented and an expected power loss is minimized. This makes it possible to ensure that no flow separation occurs over the rotor blade. Therefore, power loss can be minimized. Due to the location-specific design of the arrangement of the vortex generators, which design depends on the acoustic power level to be set, the occurrence of flow separation can be switched to a significantly reduced blade pitch angle. This makes it possible to operate the rotor blade in an optimal angle of attack range.

The vortex generators can be brought into a radial position in the longitudinal direction of the respective rotor blade, which radial position is determined as a function of the reduced rated rotor speed.

In a preferred refinement, the determination of the radial position which the vortex generators occupy in the longitudinal direction of the respective rotor blade is carried out as a function of the acoustic power level to be set, so that an increase in the blade pitch angle, which is necessary in the case of a relatively low acoustic power level to be set and which is caused by the necessary reduction in the rated rotor speed, is compensated. Thus, an increase of the blade pitch angle or pitch angle may be reduced or even completely avoided.

The determination of the radial position at which the vortex generator terminates and the blade pitch angle of the rotor blade with which the wind power plant operates may be performed in accordance with the acoustic power level to be set such that during a hybrid operation comprising operating periods of the power optimizing operating mode and the noise reducing operating mode, a production loss in the power optimizing operating mode is compensated at least by a production yield in the noise reducing operating mode in a certain period of time.

In the power-optimized mode of operation, the occupancy of vortex generators to relatively large radial positions may result in production losses. These production losses can be compensated or overcompensated by the production yield in the noise reduction mode of operation, so that during the mixing operation, a greater production yield, e.g. a greater annual energy production, can be obtained over a certain period of time. Thus, the method may also provide that production losses in the power optimized operation mode may be overcompensated by production gains in the noise reduction operation mode over a certain period of time, e.g. one year, such that a larger annual energy production is obtained, e.g. by adjusting the occupancy of the vortex generators and the blade pitch angle of the rotor blades, than without such adjustment. The reduction in annual energy production of the power-optimized operating mode by occupying the rotor blades to a radial position more outward in the longitudinal direction of the respective rotor blade is generally lower than the increase in annual energy production of the noise-reducing operating mode, and therefore, the production loss in the power-optimized operating mode may be generally compensated for or overcompensated for by the production gain in the noise-reducing operating mode.

The method may provide for example a hybrid operation in case different sound power level requirements are applied at the location of the wind power plant during day and night time or during specific rest times. For example, the wind power plant may be operated in a power optimized mode of operation during the daytime when less stringent acoustic power level requirements are applied, and in a noise reduction mode of operation during the nighttime when more stringent acoustic power level requirements are applied.

In the power-optimized operating mode, the wind power plant is operated at a power-optimized rated rotor speed to produce a power-optimized rated power. In the noise reduction mode of operation, the wind power plant is operated at a reduced rated rotor speed compared to the power optimization mode of operation to meet the acoustic power level requirements. The noise reduction mode of operation produces a reduced power rating compared to the power optimized power rating. The annual energy production of the wind power plant depends, among other things, on the period of time the wind power plant is operated in the power optimizing operation mode and the period of time the wind power plant is operated in the noise reducing operation mode. During hybrid operation, the wind power plant may be operated in other partial-load operation modes in addition to the noise reduction operation mode.

There are different sound power level requirements at different locations, for example, there may be sound power level requirements so that reduced sound power levels have to be observed already in the partial load range or shortly before the rated power is reached. Therefore, the sound power level to be set must then be selected to meet the sound power level requirement.

Preferably, the setting of the blade pitch angle may be performed according to the radial position determined for the occupancy of the vortex generator. Thus, an optimum design can be ensured.

The method may provide that, in a boundary condition in which the wind power plant emits a sound power level which is lower than or equal to the sound power level to be set, the parameters may be iteratively optimized depending on the nominal rotor speed, the blade pitch angle of the rotor blade and the radial position in the longitudinal direction of the respective rotor blade which the vortex generator occupies until the boundary condition is met. The parameter may be, for example, the amount of power generated by the wind power plant over a certain period of time, such as the annual power generation of the wind power plant. The boundary condition may be, for example, reaching a maximum number of iteration steps or a convergence condition. The convergence condition may be, for example, that the difference between the annual energy production established in two successive iteration steps is less than a predetermined limit value. This may enable the nominal rotor speed, the blade pitch angle of the rotor blade and the radial position occupied by the vortex generators in the longitudinal direction of the respective rotor blade to be matched to each other such that a maximum annual energy production is achieved taking into account the acoustic power level requirements.

Preferably, the occupancy of the rotor blades by the vortex generators may be performed taking into account a specific operational management, in particular a specific power rating with which the wind power plant is operated at one location. In terms of operational management, it is conceivable to provide the wind power installation type with a power rating based on location and acoustic power level. For this purpose, the nominal power can be set by setting the nominal rotor speed. The operation of the wind power plant at the respective rated rotor speed and rated power may depend on varying general conditions.

For example, the wind power plant may be operated in a noise reduction mode of operation at a reduced rated rotor speed to meet acoustic power level requirements. If the acoustic power level requirement does not limit the rated rotor speed of the wind power plant, the wind power plant may be operated at a relatively high rated rotor speed during power-optimized operation. A relatively high rated rotor speed, in particular a ratio dependent on the rated rotor speed and the rated power, results in a relatively high tip speed ratio in the rated power range and thus in a reduced angle of attack and thus a reduced risk of flow separation. This, in turn, results in a reduction of the occupancy of the vortex generators in the radial direction and this may result in less noise or lower acoustic power levels and in an increase in power.

The tip speed ratio is defined as the ratio of the speed of the rotor blade tip at the rated rotor speed to the rated wind speed when the rated power is reached in the respective operating mode. Thus, the tip speed ratio depends on the ratio of the rated rotor speed and the rated power. By varying the rated rotor speed and/or the rated power, a relatively high or a relatively low tip speed ratio may be produced accordingly. It may be advantageous to occupy wind power plants with plant types operating at different power ratings to different extents with vortex generators in the radial direction. In particular, during the mixing operation, the occupancy of the vortex generators may depend on how high the respective proportions of the power optimization operation mode and the noise reduction operation mode are in the production period of the wind power plant.

According to a preferred refinement, a plurality of blade setting characteristics can be stored, and one blade setting characteristic can be selected from the stored blade setting characteristics as a function of the radial position determined for the occupancy of the vortex generator, and can be used for setting the blade pitch angle.

The wind power plant may be operated at a nominal rotor speed depending on the position. The determination of the radial position of the respective rotor blade in the longitudinal direction of the respective rotor blade, which is occupied by the vortex generator, can be determined as a function of the rated rotor speed.

The radial position which the vortex generator occupies in the longitudinal direction of the respective rotor blade is determined depending on the proportion of the noise-reducing operating mode at the location of the wind power plant.

The wind power plant is not usually intended to be operated in a noise reduction mode of operation all year round, but for example only for a certain proportion, which may fluctuate between 0% and 100% and which can be easily determined for location. Depending on the proportions in which the wind power plant is intended to operate in the noise reduction mode of operation, different optimal occupancies of the vortex generators may result. Therefore, even in the case of the noise reduction operation, the Annual Energy Production (AEP) can be maximized.

Here, different noise reduction operation modes may also be combined, such as strictly limited and less strictly limited, for example to 98 db and 100 db. Different degrees of restriction on the noise reduction operation mode may be incorporated into determining the proportion of noise reduction operation modes having different degrees of importance, with less stringent restrictions having less weight.

The operational management of the wind power plant, in particular the setting of the blade pitch angle, is preferably additionally determined according to the proportion of the noise reduction operation mode at the location of the wind power plant.

It has been found that optimal occupancy of the rotor blades and associated optimal operational management can optimize annual energy production as a function of the proportion of noise reduction operating modes.

According to a second aspect, the invention also relates to a rotor blade having a suction side and a pressure side, wherein at least a plurality of vortex generators are arranged on the suction side between a rotor blade root and a rotor blade tip, wherein the arrangement of the vortex generators in the longitudinal direction of the respective rotor blade into radial positions is carried out as a function of the position-specific sound power level to be set. The occupancy of the respective rotor blade by the vortex generator in dependence on the position-specific sound power level enables the operation of the wind power plant with the rotor blades with a sound power level that meets the position-specific sound power level requirements. The wind power plant may also be operated with a smaller blade pitch angle preventing flow separation. This may result in greater throughput.

In this case, the arrangement of the vortex generators in the direction of the rotor blade tip from the rotor blade root to the radial position of the rotor blade is performed such that during a noise-reducing operation with a reduced rated rotor speed compared to the power-optimizing operation, by setting the blade pitch angle of the rotor blade to match the arrangement of the vortex generators, the expected flow separation due to the reduced rated rotor speed is prevented and the expected power losses are minimized.

It may therefore be advantageous to provide for the rotor blades of a wind power plant of a plant type which must meet different acoustic power level requirements to be occupied to a different extent also with vortex generators in the radial direction.

The present disclosure is particularly advantageous for rotor blades that show a particular geometry, referred to as an elongated blade. In recent years, the trend in slender blades has been to reduce the profile depth while increasing the rotor diameter substantially. In the context of the present disclosure, an elongated blade is referred to as any blade having a higher design lift coefficient or a higher design tip speed ratio TSR when compared to an onshore or Offshore version of the Reference Turbine disclosed in the 2009 report NREL/TP-500 38060 "Definition of a 5-MW Reference Wind Turbine for offset System Development" of Jonkman, j. Thus, the aerodynamic characteristics of the elongated blade are facilitated by increasing the design tip speed ratio and/or increasing the design lift coefficient.

It is known that such elongate blades are greatly affected by the arrangement and layout of the vortex generators.

It is particularly preferred to have rotor blade geometries that experience low aerodynamic loads near the rotor blade tip. A low aerodynamic load is in particular understood to comprise a predetermined load reserve difference with respect to a theoretical maximum aerodynamic load, for example 20% or 30% or any other suitable value. Thus, by using the arrangement and occupancy of vortex generators according to the present disclosure, the available aerodynamic reserve can be used to increase the energy output.

Preferably, the area near the rotor blade tip is referred to as the outermost 20% of the blade length, while other definitions of the blade tip area are contemplated.

It is preferred that the axial induction factor distribution near the blade tip exhibits a sufficient distance from, and in particular sufficiently below, the Betz limit. In the context of the present disclosure, it is preferred that a sufficient distance from the Betz limit is applied if the induction factor is below 0.3, preferably below 0.2 and more preferably in the range of 0.1 to 0.15, while other boundaries are also feasible.

In a preferred embodiment, the rotor blades exhibit a decreasing aerodynamic load as the radial position increases. Such rotor blades have proven to be particularly effective when used with the present disclosure.

In a third aspect, the present disclosure also relates to a wind power plant comprising an aerodynamic rotor with rotor blades whose blade pitch angle can be adjusted, wherein the rotor can be operated at a settable nominal rotor speed, and a control system, characterized in that the control system is designed to operate the wind power plant according to the method according to the first aspect or its modification.

The rotor may preferably have at least one rotor blade according to the second aspect.

In a fourth aspect, the present disclosure also relates to a wind farm having a plurality of wind power plants according to the third aspect.

Drawings

The disclosure will be described in more detail below on the basis of one possible exemplary embodiment with reference to the accompanying drawings, in which:

FIG. 1 shows a wind power plant according to the present disclosure;

FIG. 2 shows a schematic view of a single rotor blade;

FIG. 3 shows by way of example different curves of angle of attack reserve for a rotor blade with respect to a standard rotor radius for two different operating situations;

FIG. 4 shows exemplary curves of lift-to-drag ratios for different operating situations of a wind power plant;

FIG. 5 shows exemplary power curves for different operating scenarios;

FIG. 6 shows, by way of example, two blade pitch angle characteristic curves for two different operating scenarios;

FIG. 7 illustrates an exemplary annual energy production as a function of different average wind speeds;

FIG. 8 illustrates a rotor characterization map for two different operating scenarios, wherein the rotor characterization map represents power coefficients dependent on blade pitch angle and tip speed ratio; and

fig. 9 shows by way of example the difference in annual energy production depending on the proportions of power-optimized and noise-reduced operating modes for different operating situations.

Detailed Description

The description of the present disclosure according to the examples with reference to the drawings is basically made in an illustrative manner, and elements explained in the respective drawings may be exaggerated therein to improve illustration, and other elements may be simplified. Thus, for example, fig. 1 shows the wind power plant itself in a diagrammatic manner, with the result that the arrangement of the vortex generators provided cannot be seen clearly.

Fig. 1 shows a wind power plant 100 with a tower 102 and a nacelle 104. The nacelle 104 is provided with a rotor 106 having three rotor blades 108 and a rotator. During operation, rotor 106 is set in rotational motion by the wind, driving a generator in nacelle 104. The blade angle of the rotor blade 108 may be set. The blade pitch angle γ of the rotor blades 108 may be changed by a pitch motor arranged at a rotor blade root 114 (see fig. 2) of the respective rotor blade 108. The rotor 106 is operated at a nominal rotor speed n which may be set according to the operation mode.

In the exemplary embodiment, the wind power plant 100 is controlled by a control system 200, which control system 200 is part of the overall control system of the wind power plant 100. The control system 200 is typically implemented as part of the control system of the wind power plant 100.

The wind power plant 100 may be operated in a power-optimized or noise-reduced mode of operation by means of the control system 200. In the power-optimized operating mode, the wind power plant 100 produces the optimum power that can be produced with the wind power plant 100. In the noise reduction mode of operation, the wind power plant 100 is operated at a reduced rated rotor speed compared to the power optimization mode of operation in order to set a sound power level that is less than or equal to the sound power level pre-specified by the sound power level requirement.

A plurality of such wind power plants 100 may form part of a wind farm. The wind power installations 100 are in this case subject to various environmental and general conditions depending on their location. In particular, the sound power level requirements of the wind power plant may differ depending on its location. Furthermore, the wind farm characteristics to which the wind power plant is exposed during diurnal and seasonal variations may vary greatly. Wind farms are characterized by a large number of parameters. The most important wind field parameters are average wind speed, turbulence, vertical and horizontal shear, variation in height of the wind direction, oblique incident flow and air density.

In view of the acoustic power level to be set, one measure for operating the wind power plant is arranged for counteracting the increase of the angle of attack on the rotor blade by increasing the blade pitch angle γ, also called pitch angle, starting from a certain power, to avoid the threat of flow separation in the central region of the rotor blade 108 which would result in large power losses, the increase of the angle of attack being caused by the reduced rated rotor speed during the noise reduction operation. The increase of the blade pitch angle γ leads in this case to power losses of the wind power plant 100, but these power losses usually prove to be smaller than the power losses due to the flow separation occurring at the respective rotor blade 108.

In accordance with the present disclosure, it is now proposed to consider the occupancy of the vortex generator 118 on the rotor blade 108 in a design that matches the position to be set with a relatively low acoustic power level, as illustrated by way of example in fig. 2. The vortex generators 118 fitted on the extension area in the central portion of the rotor blade 108 according to the acoustic power level to be set determined at the position of the wind power plant 100 prevent flow separation in the central portion and thus an increase of the blade pitch angle γ or setting of a smaller blade pitch angle may be reduced and this may result in a greater overall yield of the wind power plant 100.

FIG. 2 illustrates a schematic view of a single rotor blade 108 having a rotor blade leading edge 110 and a rotor blade trailing edge 112. Rotor blade 108 has a rotor blade root portion 114 and a rotor blade tip portion 116. The distance between the rotor blade root 114 and the rotor blade tip 116 is referred to as the outer radius R of the rotor blade 108. The distance between the rotor blade leading edge 110 and the rotor blade trailing edge 112 is referred to as the profile depth T. At the rotor blade root 114, or generally in the region near the rotor blade root 114, the rotor blade 108 has a greater profile depth T. In contrast, at the rotor blade tip 116, the profile depth T is much smaller. In this example, after the blade inner region increases, the profile depth T decreases significantly from the rotor blade root 114 to the middle region. A separation point (not shown here) may be provided in the middle area. From the middle region to the rotor blade tip 116, the profile depth T is almost constant, or the reduction in profile depth T is significantly reduced.

The illustration in FIG. 2 shows the suction side of the rotor blade 108. Vortex generators 118 are arranged on the suction side. Vortex generators 118 are envisaged as an alternative modification to the active or passive elements for influencing the flow. Although the vortex generators 118 in the illustrated example are shown as being disposed on the suction side of the rotor blade 108, alternatively or additionally, the vortex generators 118 may be populated on the pressure side of the rotor blade 108 in accordance with the present disclosure. The vortex generators 118 may be occupied in the region of the rotor blade leading edge 110 or in other regions at another location between the rotor blade leading edge 110 and the rotor blade trailing edge 112. The region occupied by the vortex generator 118 begins in the region of the rotor blade root 114 and runs in the direction of the rotor blade tip 116.

The vortex generator 118 extends in radial direction to a position P on the rotor blade relative to the rotor 106_AOr P_B. In this case, the corresponding position P on the rotor blade 108_AOr P_BIs designated as the radial position relative to the normalized radius R/R. Representing positions on the rotor blade 108 along the longitudinal axis of the rotor blade as respective positions P based on the radial position of the normalized radius R/R_A、P_BRelative to the outer radius R of rotor 108_a、r_bOr alternatively, rotor blade length. Thus, the associated position P on rotor blade 108 as the radial position R/R_AOr P_BMay be indicated by a value ranging from 0 (zero) to 1 (one).

In order to increase the annual energy production of the wind power plant 100 using the rotor blades 108, the vortex generators 118 are arranged to a radial position R/R in the longitudinal direction of the rotor blades 108 depending on the position-specific sound power level to be set. The arrangement of the vortex generators 118 from the rotor blade root 114 to the radial position R/R of the rotor blade 108 in the direction of the rotor blade tip 116 is performed such that in a noise-reducing operating mode with a reduced rated rotor speed compared to the power-optimized operation, by setting the blade pitch angle γ of the rotor blade 108 to match the arrangement of the vortex generators 118, the expected flow separation due to the reduced rated rotor speed is prevented and the expected power losses are minimized.

FIG. 3 illustrates angle of attack reserve α on rotor blade 108 for two exemplary different operating scenarios (case A and case B) listed in the following table_reserveDifferent curves 302, 303 (case B) and 304, 305 (case a) with respect to the radial position R/R. Cases A and B of the operating situation are at the radial position r of the rotor blade 108 occupied by the vortex generator 118_A、r_BOr the position P of the rotor blade 108 occupied by the vortex generator 118_A、P_BAnd blade pitch angle characteristic curves 602 (case B) and 604 (case B) selected for operationA) (see fig. 6) are different from each other.

In the graph of fig. 3, the end point occupied by the vortex generator 118 in the longitudinal direction of the rotor blade 108 is shown as being evident by means of a sudden drop in the angle of attack reserve.

The angle of attack reserve depends on the wind speed; curves 302, 304 are shown for an exemplary wind speed of 6m/s, while curves 303, 305 show curves for wind speeds where there is a minimum angle of attack reserve. The wind speeds on which curves 303 and 305 are based need not be identical in practice and are likely to be different, since the arrangement of the vortex generators 118 has a considerable influence on the wind speed dependence of the angle of attack reserve.

In both case a and case B, the wind power plant 100 is subjected to the same acoustic power level requirements, and therefore in case B and case a the operating parameters of the wind power plant 100, in particular the nominal rotor speed in the noise reduction operating mode, the blade pitch angle of the rotor blades and the radial position of the rotor blades 108 occupied by the vortex generators 118 are selected such that the acoustic power level they emit to be set is equal to or less than the acoustic power level dependent on the acoustic power level requirements.

Operation situation table:

case B	Vortex generator up to rBCharacteristic curve P of blade pitch angleB
		Case A	Vortex generator up to rACharacteristic curve P of blade pitch angleA

In case B, the vortex generator is arranged to position P_BAnd is andthe wind power plant is operated with a blade pitch angle characteristic curve 602. The combination of the occupancy of the vortex generators and the blade pitch angle γ makes it possible to obtain a suitable angle of attack reserve over the entire length of the rotor blade and thus avoid stall.

Case a describes the following case: depending on the situation, the vortex generator ends up in a position, in particular the position P_AThe change in (b) enables more reliable operation with the preferred blade pitch angle characteristic 604 without stall. Blade pitch angle γ of blade pitch angle characteristic 604 is less than blade pitch angle γ of blade pitch angle characteristic 602 (see FIG. 6). This makes it possible to generate more power (see fig. 5) and thus to obtain a greater total annual energy production (see fig. 7). In particular, the wind power plant can be operated with a higher power factor in case a than in case B (see fig. 8).

Thus, a method for designing and operating a wind power plant 100 for generating electrical power from wind, for example from fig. 1 with rotor blades 108, the rotor blades 108 being occupied by a vortex generator 118 as shown in fig. 2, is provided for case a. The radial position R/R occupied by the vortex generator 118 in the longitudinal direction of the respective rotor blade 108 is determined depending on the sound power level to be set at the location of the wind power plant 100. Furthermore, the blade pitch angle γ of the rotor blade 108 with which the wind power plant 100 is operated may be determined in dependence of the acoustic power level to be set at the location of the wind power plant 100. In the noise reduction mode of operation, the wind power plant 100 may be operated at a reduced rated rotor speed compared to the power optimization mode of operation depending on the sound power level to be set at the location of the wind power plant 100.

The radial position R/R at which the vortex generator 118 terminates and the blade pitch angle γ of the rotor blades 108 with which the wind power plant 100 is operated may also be determined depending on the acoustic power level to be set, such that an expected flow separation due to a reduction of the rated rotor speed is prevented and an expected power loss is minimized.

The occupancy of the vortex generators 118 can be realized in the longitudinal direction of the respective rotor blade 108 up to a radial position R/R, which is determined as a function of the reduced nominal rotor speed.

The determination of the radial position R/R occupied by the vortex generator 118 in the longitudinal direction of the respective rotor blade 108 may also be performed in dependence of the acoustic power level to be set such that an increase of the blade pitch angle γ, which is necessary in case of a relatively low acoustic power level to be set and which is caused by a necessary reduction of the rated rotor speed, is minimized.

Furthermore, the determination of the radial position R/R at which the vortex generator 118 terminates and the blade pitch angle γ of the rotor blade 108 with which the wind power plant 100 operates may be performed in dependence of the acoustic power level to be set such that during a hybrid operation of the operation time periods comprising the power optimization operation mode and the noise reduction operation mode, a production loss in the power optimization operation mode is at least compensated by a production yield in the noise reduction operation mode in the specific time period.

The blade pitch angle γ may be set according to the radial position R/R determined for the occupancy of the vortex generator 118.

The occupancy of the rotor blades 108 by the vortex generators 118 may be performed taking into account a specific operational management, in particular a specific power rating at which the wind power plant 100 is operated at one location. Here, the nominal power may be taken into account during the mixing operation, or a reduced nominal power may be taken into account in the noise reduction operation mode.

For example, a plurality of blade setting characteristics may be stored in the control system 200. One blade setting characteristic may be selected from the stored blade setting characteristics depending on the determined radial position R/R for the occupancy of the vortex generator 118 and may be used for setting the blade pitch angle γ.

Fig. 4 illustrates exemplary curves 402, 403 and 404, 405 of lift-to-drag ratios for case B and case a for two different operating scenarios. Curves 402, 403 are established for case B. Curves 404, 405 are established for case a, where the respective curves are based on different wind speeds, as in fig. 3. Curves 402, 404 are shown for an exemplary wind speed of 6m/s, while curves 403, 405 show curves for wind speeds where the lowest angle of attack reserve exists.

In the first example, it can be seen that the lift-drag ratio according to curve 402 is small up to a radial position R/R <0.37, and rises from this radial position R/R with a small jump and increases outward to rotor blade tip 116 up to a higher radial position R/R > 0.37. The low value of the lift-to-drag ratio in curve 402 is due to occupancy by vortex generators 118, which generally results in an increase in the drag coefficient.

The plot 404 of lift-to-drag ratio in case a is substantially similar in nature to plot 402 up to a radial position R/R of about 0.37. However, starting at a radial position R/R of about 0.39, the lift-to-drag ratio of curve 404 is always higher than the lift-to-drag ratio of curve 402.

To avoid flow separation on rotor blade 108, blade pitch angle γ is increased. Thus, for example, the blade pitch angle γ, i.e. the blade pitch angle characteristic curve 602 or 604, is selected as the occupancy characteristic of the vortex generators. An increase in blade pitch angle results in a decrease in angle of attack α on rotor blade 108 over the entire rotor radius R, such that it is ensured that angle of attack α is within the allowed range and that no flow separation occurs.

Here, the blade pitch angle preferably extends from 0 ° to 90 ° from outside the rotor plane to the wind direction assumed perpendicular to the rotor plane. Thus, an increase in the pitch angle or blade pitch angle causes the profile chord of the rotor blade to rotate towards the wind direction. Thus, an increase in blade pitch angle results in a decrease in angle of attack.

However, a disadvantage of this procedure is that, due to the increased blade pitch angle γ, the so-called pitching, of the rotor blades 108, the angle of attack α is also reduced in the outer regions of the rotor blades 108, i.e. also in regions where there is generally no risk of flow separation. Thus, a reduction of the angle of attack due to pitching may directly lead to a power loss of the wind power plant 100.

It is therefore proposed that the vortex generators 118 occupy a radial position R/R in the longitudinal direction of the respective rotor blade 108, which is determined as a function of the sound power level to be set at the location of the wind power plant 100. The described disadvantages of the power loss of the wind power plant 100 caused by pitching can thus be reduced in particular. Specifically, in each case, a smaller blade pitch angle may be set by extending the occupancy of rotor blade 108 by vortex generator 118.

As has been discussed further above, during operation of the wind power plant 100, the largest increase in angle of attack occurs at the central portion of the rotor blade 108. In the radial direction with the position P of the fitted vortex generator 118_BThis is particularly true at adjacent radial locations. To address this situation, in the event of a noise reduction operation being performed for the wind power plant 100 at a position having a lower acoustic power level, the lower acoustic power level is set such that the occupancy of the rotor blades 108 by the vortex generator 118 extends radially beyond the position P_BTo position P_A. Thus, the central part of the rotor blade, in particular the position P, is counteracted_BAnd position P_AThe risk of flow separation in between.

As further discussed, the occupancy of the rotor blades 108 by the vortex generators 118 is accompanied by a reduction in the lift-to-drag ratio in the region of the vortex generators 118. With reference to the illustration in fig. 4, the problem of the reduction of the lift-to-drag ratio due to the occupancy of the vortex generator 118 is explained for the operating situation of case a. By extending the occupancy of the vortex generator 118 to a radial position, for example a radial position where R/R is 0.39, at position P compared to the case in operating situation B_AThe lift-to-drag ratio to this position is kept at a lower level. However, by appropriate design, more power is again generated in the outer region of rotor blade 108, i.e. having radial position R/R>0.39, which correlates with the subsequently established yield increase.

The increase in production due to the increase in power generation in the outer region of the rotor blade 108 is shown by way of example in FIG. 5. Fig. 5 shows by way of example different power curves 502 and 504 for case B and case a of the operating scenario. In case B, a power curve 502 is established, while in case a, a power curve 504 is established.

According to the power curves 504 and 502, a higher power consumption is possible for a specific range within the partial load range of the wind speed v in case a than in case B. This increased power consumption in case a leads to a production yield by which the vortex generator 118 in the overshoot position P can be compensated or overcompensated_BUp to position P_AIncreased consumption in the additionally occupied area.

FIG. 6 shows, by way of example, two blade pitch angle characteristic curves 602 and 604 for two different operating scenarios. Blade pitch angle characteristic 602 is based on the operating scenario in case B of control of blade pitch angle γ. Blade pitch angle characteristic 604 is based on the operating scenario for case A where blade pitch angle γ is controlled by control system 200. As can be seen from curves 602 and 604, blade pitch angle γ for case A is always less than blade pitch angle γ for case B. In particular, the minimum blade pitch angle γ_AminLess than minimum blade pitch angle gamma_Bmin。

In this example, exemplary blade pitch angle characteristics 602, 604 are defined as a piecewise-defined characteristic having three linear segments. Up to a first power threshold value P_Amin1Or P_Bmin1Blade pitch angle is maintained at the corresponding minimum blade pitch angle γ found for blade pitch angle characteristics 602, 604_AminOr gamma_Bmin. From the first power threshold P_Amin1Or P_Bmin1Initially, a blade pitch angle delta Δ γ occurs that is linear with power_Amin1Or Δ γ_Bmin1Until reaching the second power threshold P_Amin2Or P_Bmin2Until now. From the second power threshold P_Amin2Or P_Bmin2At the beginning, a blade pitch angle increment Δ γ in linear power relationship also occurs_Amin2Or Δ γ_Bmin2Until the rated power is reached. Blade angle increment delta gamma_A、Bmin2May be greater than, less than, or equal to the blade angle increment Δ γ_A、Bmin1。

It has been found that the blade pitch angle characteristic curve used for this purpose may be defined by the minimum blade pitch angle γ_minThe power threshold at which the blade pitch angle starts to increase and two linear regions adjacent to each other with a constant blade pitch angle increment are defined particularly successfully. It goes without saying that other functions may also be used for the blade pitch angle, for example a relatively simple function of the blade pitch angle increment with only one single linear region, or more complex functions such as more than just a first order linear function of power. The method found here provides a compromise between the complexity of the optimization method and the implementation in the control system of the wind power plant and at the same time optimizing the energy production as much as possible, i.e. a deviation from the ideal blade pitch angle characteristic curve which is as small as possible, which is particularly suitable in practice.

Another aspect takes into account that the position-and operation-mode-dependent power rating P is provided for the operation management of a wind power plant type_rated. In this case, the nominal power P can be adjusted by adjusting the nominal rotor speed_rated. At the same power, the relatively high rated rotor speed results in a rated power P_ratedA relatively high tip speed ratio in the range and thus a reduced angle of attack alpha. Thus reducing the risk of flow separation. However, a relatively high nominal rotor speed leads to a relatively high sound power level, so that when the nominal rotor speed is adjusted where the sound power level requirements have to be fulfilled at the location, the nominal rotor speed has to be adjusted in a corresponding manner.

Fig. 7 shows the annual energy production AEP as a function of different average wind speeds vd, illustrated using a bar graph 702 (case B) and a bar graph 704 (case a). In case a, the annual energy production AEP for all average wind speeds vd is always higher than in case B. Thus, vortex generator 118 occupies position P for rotor blade 108 when the acoustic power level requirement is met_AAnd setting the blade pitch angle γ according to the blade pitch angle characteristic 604 in combination may be such that the rotor blade 108 may be more or less numerous than the vortex generator 118Occupying position P in a position-dependent manner_BAnd a higher annual energy production is obtained in the case where the blade pitch angle γ is set according to the blade pitch angle characteristic curve 602.

Fig. 8 shows a rotor characteristic diagram 802 (case B) and a rotor characteristic diagram 804 (case a) depending on the power coefficient of the blade pitch angle γ and the tip speed ratio SLZ. In case a, the wind power plant 100 may be operated with a relatively high power coefficient Cp. A power coefficient of high Δ Cp can be achieved compared to the B case.

Fig. 9 shows by way of example the annual energy production difference Δ AEP during hybrid operation of a wind power plant, which depends on the ratio ABM of the power optimization and noise reduction operation modes for different operating situations. The proportion of the noise reduction mode of operation is between 0% and 100%.

A curve 900 is shown as a reference, the curve 900 showing the annual energy production of a wind power plant with occupancy of known vortex generators and known operational management. Further curves 910, 912, 914, 920, 922, 924 show the annual energy production difference Δ AEP relative to the curve 900, wherein in fig. 9 the curves above the curve 900 represent an increase in production and the curves below the curve 900 represent a decrease in production.

Curves 900, 910 and 920 represent the situation where the radial position R/R at which the occupancy of the rotor blade by the vortex generator ends continuously increases, i.e. the radial position R/R at which the occupancy of the rotor blade by the vortex generator ends is greater for curve 920 than for curve 910 and greater for curve 910 than for curve 900. Apart from the different occupancy of the vortex generators, the wind power plants on which the curves 900, 910, 920 are based do not differ, i.e. the operational management of the wind power plants is the same. It can be seen that the reduction in annual energy production is independent of the ratio ABM, that is to say that the extension of the occupancy of the rotor blades in the direction of the rotor blade tip has an adverse effect on the AEP with operational management being maintained.

In curves 912 and 922 and 914 and 924, the operational management has been adjusted compared to curves 910 and 920, wherein the occupancy of the vortex generators remains unchanged as in curves 910, 920. Curves 912 and 922 and 914 and 924, respectively, differ in blade pitch angle curve, an example of which is shown in FIG. 6.

Curves 912 and 922 have, for example, a common first power threshold, from which pitching is performed at a constant blade pitch angle rate. Curves 914 and 924 in turn have operational management of adjustments, such as modified, e.g., higher first power threshold and modified blade pitch angle rate. The minimum blade pitch angles between the operational management systems on which curves 912 and 922 and curves 914 and 924, respectively, are based may also differ.

It can be seen that for a wide range of scaled ABMs for noise reduction modes of operation, there is an ideal combination of occupancy and operational management of vortex generators, as shown by curve 914, where curve 914 provides a significant annual energy production increase as compared to curve 900 when scaled ABM exceeds a certain value. However, comparing curve 924, further extension of the occupancy of the vortex generator will result in a drop compared to curve 914. Thus, optimal occupancy and operational management can be found according to the situation. As a result, during the mixing operation, the vortex generators occupy the radial position R/R for the rotor blades and the blade pitch angle and the rated rotor speed are adjusted depending on the position-specific acoustic power level itself such that a yield gain can be achieved. Here, the proportion ABM of the noise reduction operation mode during the mixing operation may be crucial (see cross points 915, 913, 925, and 923).