DE102014225637A1 - Method and device for monitoring a wind energy plant - Google Patents

Abstract

A method is provided for monitoring a wind turbine (100), the wind turbine (100) having a rotor (106) driving a driveline (112) with a first rotor blade (108a) and at least one second rotor blade (108b) A step of determining an imbalance information (126) representing an imbalance of the wind turbine (100) using a rotation signal (124) to monitor the wind turbine (100), the rotation signal (124) including angular velocity and / or torque at the drive shaft (100). 110).

Description

The present invention relates to a method for monitoring a wind turbine, to a corresponding device for monitoring a wind turbine, to a corresponding wind turbine and a corresponding computer program.

Wind turbines are built higher and are therefore exposed to heavier loads. In part, after the construction of a wind turbine, the rotor is balanced. For this purpose, the leaves are trimmed, are placed in them in the balancing weights, which eliminate mass imbalance. Furthermore, aerodynamic imbalances can be a burden on components of the wind turbine. Later, an offline survey can be done by on-site staff at specific intervals. Alternatively, a minimization of aerodynamic imbalances is performed by adjusting the bending moments during one revolution of the wind turbines.

Against this background, with the approach presented here, a method for monitoring a wind turbine, a corresponding device that uses this method, a wind turbine and finally a corresponding computer program according to the main claims are presented. Advantageous embodiments emerge from the respective subclaims and the following description.

The presented approach is based on the finding that an imbalance in the rotor of a wind energy plant can be determined by using two rotational angle signals, which represent the profile of the rotational angle of two rotor blades.

The approach presented here provides a method for monitoring a wind turbine, the wind turbine having a driveline driving rotor having a first rotor blade and at least a second rotor blade, the method comprising at least the following step:
Determining an imbalance information representing an imbalance of the wind turbine using a rotation signal to monitor the wind turbine, wherein the rotation signal represents an angular velocity and / or torque on the drive shaft.

A wind turbine can be understood as meaning a wind turbine or a wind turbine. In this case, a rotor of the wind turbine is rotated by wind or wind energy in rotation and driven with the rotor, an electric generator. The rotor may have at least two rotor blades, in particular three rotor blades, but also four or more blades. The rotation signal may represent a rotation frequency, a torque, a rotation angle or an acceleration about an axis of rotation. A profile of a rotation angle or the angular velocity of a rotor blade or the torque of the drive shaft can be detected by a sensor such as an acceleration sensor, a rotation rate sensor or gyroscope, a rotation angle sensor or Inclinometer or a strain gauge or derived from a corresponding sensor signal. In this case, the sensor can be arranged at a reference point of a rotor blade of the wind energy plant. The imbalance may characterize a principal axis of inertia of the rotor which does not correspond to a rotational axis of the rotor. An imbalance of the rotor can lead to vibrations and increased wear on the wind turbine. Thus, a mass imbalance or aerodynamic imbalance of the wind turbine can be determined.

Furthermore, a phase angle of the rotary signal can be determined to a reference zero point. In this case, the unbalance information can be determined using the phase position. Thus, a zero crossing of the rotation signal may differ from the expected reference zero point. From the phase position, which can also show a shift of the rotational signal to a reference rotational signal or an expected rotational signal, an imbalance information can be obtained. A phase shift can correspond to an angular position of a mass imbalance.

In the step of determining, a first blade passing frequency for the first rotor blade and a second blade passing frequency for the second rotor blade may be detected using the rotation signal. In the step of determining, a blade passing frequency per rotor blade of the rotor can be determined using the rotation signal. In this case, the imbalance information can be determined using a phase angle between the first sheet passing frequency and the second sheet passing frequency. Thus, a phase angle between at least two Blattpassierfrequenzen be determined. The imbalance information may be determined using the phase relationship between the sheet passing frequencies.

The rotation signal may comprise a first rotation angle signal as the course of a first reference point on the drive shaft and a second rotation angle signal as the course of a second reference point on the drive shaft. The first reference point on the first rotor blade and the second reference point on the second rotor blade may correspond to the position with respect to the rotor blade. So can out an angle between the two reference points or from an angle between the two rotational angle signals are closed at an angle between the two rotor blades. The first rotational angle signal may represent a phase angle of a first rotor rotational frequency of the first rotor blade. The second rotational angle signal may represent a second phase position of a second rotor rotational frequency of the second rotor blade. Thus, simply a difference of the phase position of the first rotor rotational frequency and the phase position of the second rotor rotational frequency can be formed.

The first rotational angle signal may represent a first signal provided by a first sensor located at the first reference point on the first rotor blade, and the second rotational angle signal may represent a second signal provided by a second sensor disposed at the second reference point on the second rotor blade. Thus, a difference angle between the two reference points can be determined. The difference angle can be compared with a desired angle. A deviation of the difference angle from the target angle may indicate an imbalance.

The first sensor may be embodied as a first acceleration sensor or a first magnetic sensor. The second sensor may be designed as a second acceleration sensor or a second magnetic sensor. The imbalance information can be determined using a rotational position curve of the respective rotor blade provided by the sensors. In this case, the rotational position course in each case represent a rotational position of a rotor blade of the wind turbine over time.

It is also favorable if, in one embodiment, the method has a step of reading in the first rotational angle signal and / or the second rotational angle signal and / or the rotational speed of the component of the driveline and / or a rotor rotational speed of the component of the driveline. Thus, the signals used in the step of determining can be fed to the process.

It is also advantageous if, in one embodiment, the method comprises a step of providing a control signal. In the step of providing, a control signal for controlling at least one pitch angle of the at least one rotor blade of the rotor can be provided. Thus, the control signal can be designed to set the pitch angle for each rotor blade of the rotor individually or to provide a control variable for setting the individual pitch angles of the rotor blades. Furthermore, in the step of providing, a further control signal for controlling a rotational angle of the rotor can be provided in order to correct an aerodynamic imbalance.

The present invention further provides an apparatus for monitoring a wind turbine, wherein the apparatus is configured to implement or implement the steps of an embodiment of a method presented here in corresponding devices. Also by this embodiment of the invention in the form of a device, the object underlying the invention can be solved quickly and efficiently.

In the present case, a device can be understood as meaning an electrical device which processes sensor signals and outputs control and / or data signals in dependence thereon. The device may have an interface, which may be formed in hardware and / or software. In the case of a hardware-based embodiment, the interfaces can be part of a so-called system ASIC, for example, which contains a wide variety of functions of the device. However, it is also possible that the interfaces are their own integrated circuits or at least partially consist of discrete components.

In a software training, the interfaces may be software modules that are present, for example, on a microcontroller in addition to other software modules.

A wind energy plant with a tower, a nacelle arranged on the tower, a rotor arranged on the nacelle with a plurality of rotor blades and with a variant of a device for monitoring the wind energy plant described here are presented. In this case, advantageously, the device can be integrated into the wind energy plant. A wind turbine may include a rotor which may be driven by wind impinging on the rotor. The kinetic energy can be converted into electrical energy using a generator. The rotor shaft may comprise a transmission with at least one gear stage. The rotor can rotate about a rotor shaft while driving a generator to generate electrical energy.

A computer program product with program code which can be stored on a machine-readable carrier such as a semiconductor memory, a hard disk memory or an optical memory and is used to carry out the method according to one of the embodiments described above if the program product is installed on a computer or a device is also of advantage is performed.

The invention will now be described by way of example with reference to the accompanying drawings. Show it:

1 a schematic representation of a wind turbine according to an embodiment of the present invention;

2 a block diagram of a device according to an embodiment of the present invention;

3 a flowchart of a method according to an embodiment of the present invention;

4 a simplified representation of a phase angle of the rotor rotational frequency between two rotor blades according to an embodiment of the present invention;

5 a simplified representation of a frequency signal having a characteristic frequency at twice the rotor rotational frequency according to an embodiment of the present invention;

6 a simplified representation of a frequency signal with a meshing frequency as the characteristic frequency according to an embodiment of the present invention; and

7 a simplified representation of an amplitude of the meshing frequency over a rotor rotation according to an embodiment of the present invention.

The same or similar elements may be provided in the following figures by the same or similar reference numerals. Furthermore, the figures of the drawings, the description and the claims contain numerous features in combination. It is clear to a person skilled in the art that these features are also considered individually or that they can be combined to form further combinations not explicitly described here.

1 shows a schematic representation of a wind turbine 100 according to an embodiment of the present invention. The wind turbine 100 includes a tower 102 one on the tower 102 rotatably arranged gondola 104 and one at the gondola 104 arranged rotor 106 , In the in 1 illustrated embodiment, the rotor comprises 106 three rotor blades 108 , which is also the first rotor blade 108a , second rotor blade 108b and third rotor blade 108c be designated. The rotor blades 108 are over a rotor hub 109 connected. The rotor 106 rotates around the rotor hub 109 , or a rotor shaft 110 or rotor axis 110 , It drives the rotor 106 a drive train 112 at. The powertrain 112 can a gearbox 114 with a gear stage 116 have as well as a generator 118 on. Furthermore, the wind turbine includes 100 in the illustrated embodiment, a device 120 for monitoring the wind turbine 100 and at least one sensor 122 , In the in 1 illustrated embodiment is a sensor 122 at the gear stage 116 as well as on the generator 118 arranged. Furthermore, each is a sensor 122 on the rotor blades 108 arranged. A sensor 122 can be on the rotor shaft 110m that of a drive shaft of the wind turbine 100 corresponds to be arranged. The sensor 122 In one embodiment, it is designed to detect an acceleration, yaw rate, blade passing frequency or torque acting on it and as a sensor signal 124 or as a rotation signal 124 provide.

An imbalance of the rotor 106 usually leads to a vibration of the tower 102 the wind turbine 100 transverse to the rotor axis 110 and across the tower 102 if it is a mass imbalance. An aerodynamic imbalance can be seen in particular, if the corresponding rotor blade 108 points upwards.

The device 120 is formed, using the rotation signal representing an imbalance of the wind turbine unbalance information 126 to determine the wind turbine 100 to monitor. This represents the rotation signal 124 an angular velocity or torque. The device 120 is formed in an optional embodiment, from the rotation signal 124 to determine a sheet passing frequency per rotor blade. In an optional embodiment, the device is 120 designed, a phase angle of the rotary signal 124 to determine about it the wind turbine 100 to monitor. As the drive shaft to rotate about the rotor axis components of the wind turbine, that is, the rotor 106 with the rotor blades 108 as well as powertrain elements 112 designated.

In a particular embodiment, the device 120 formed, an imbalance of a rotor blade 108 by measuring the phase angle of the rotational angle signals between the rotor blades 108 to investigate. The necessary rotation angle signals or rotational angular position signals are either from the rotation signal 124 obtained or alternatively by detectors 122 such as acceleration sensors 122 or magnetic sensors 122 in the rotor blades 108 determined. The determined imbalance can be compensated by means of the single-sheet pitch control (individual pitch control), as far as it is an aerodynamic imbalance. A rule goal would be the phase difference of a predetermined frequency such as the harmonic rotational frequency 1p to a fixed value (for example, 120 ° for three rotor blades) to make.

Due to different deviations, it may be due to wind turbines 100 come to the occurrence of imbalances. Some typical causes of mass imbalance and aerodynamic imbalance are: an uneven mass of rotor blades 108 , an uneven distribution of the rotor blade mass, an unbalance of the hub, an eccentricity of the rotor, a bent main shaft, a pitch error of the hub (≠ 120 °), rotor blade offset in the circumferential direction, a blade angle error, deviations in the profile among the three rotor blades, a faulty pitch angle setting ( Single sheet) or a rotor blade offset in the axial direction. Furthermore, an imbalance may be temporarily caused by environmental influences. A mass imbalance may be due to a vibration of the tower head or the gondola 104 essentially transverse to the drive shaft and transverse to the main extension of the tower 102 demonstrate. An aerodynamic imbalance can be manifested by a characteristic signal change if the rotor blade concerned points vertically upwards.

It has been shown that imbalances on wind turbines 100 lead to different characteristics in various sensor measurement data. Both mass imbalances and aerodynamic imbalances lead to changes in the amplitudes and / or phase position and / or frequencies of significant oscillations of the wind turbines 100 , By means of sensors 122 in the rotor blades 108 can be, for example, the amplitude / phase position and the frequency value of the meshing frequencies of the individual gear stages 116 , which determine tower natural frequencies, the rotor rotational frequency (1p) as well as the double rotor rotational frequency (2p). As sensors 122 For example, acceleration sensors, yaw rate sensors (gyroscopes), rotational angle sensors (inclinometers) and strain gages are considered. By means of sensors 122 in the gondola 104 the wind turbines 100 For example, the generator speed, rotor speed and transmitted torque can be determined. As sensors 122 For example, acceleration sensors, incremental angle meters, protractors, rotary encoders, Hall sensors and strain gauges can be considered. On the basis of the amplitude and / or phase angle and / or frequency of the meshing frequencies of the individual gear stages, the tower natural frequencies, the rotor rotational frequency (1p) and twice the rotor rotational frequency (2p) can be detected imbalances.

The combination of the evaluation of the individual sensor data makes it possible to classify the imbalances with regard to their causes and their intensity. The comparison of the different features of several wind turbines 100 allows a qualitative statement regarding criticality. For example, it can be used to assess the priority with regard to the planned repair measures.

Aerodynamic imbalances can e.g. be corrected by controlling the pitch angle of the individual sheets, provided that each sheet is equipped with its own pitch drive.

This will be the pitch angle of each leaf 108 individually adjusted to capture the individual pitch angles for which the rotor rotational frequency (1p) and / or twice the rotor rotational frequency (2p) in the blades 108 and / or occur minimally in the drive train. After aligning the aerodynamic properties of the leaves 108 to each other via a collective adjustment of all pitch angles maximizing the performance of the wind turbines 100 ,

The device 120 Creates a detection and root cause analysis of unbalances in wind turbines (WTG) 100 by evaluation of one or more sensor signals 124 and methods for minimizing the detected aerodynamic imbalances. This is how to detect aerodynamic imbalances and mass imbalances on wind turbines 100 and minimizing aerodynamic imbalances.

Advantageously, a change, caused for example by aging, can be detected. The device 120 can be advantageous a wind turbine 100 Monitor permanently and in any operating condition and thus make faster and more accurate statements about the condition. Advantageously, a separation between aerodynamic imbalance and mass imbalance is possible. In particular, automation of a hitherto complex manual process can take place. In this case, a minimization of aerodynamic imbalances by means of different sensor signals 124 to be possible.

By means of sensors 122 in the rotor blades 108 and / or in the gondola 104 For example, it is possible to determine the frequency, amplitude and / or phase position of various vibrations and to determine therefrom a mass imbalance and / or aerodynamic imbalance. These vibrations include the rotational frequency of the rotor 106 , twice the rotational frequency of the rotor, the gear teeth meshing frequencies 116 , the tower natural frequency and the generator speed. A detected aerodynamic imbalance is minimized in one embodiment by a method of single blade adjustment. In this case, the pitch angle of the rotor blades 108 be adjusted.

By reducing an aerodynamic imbalance by means of individual pitch angle adjustment The causes of mass imbalance or aerodynamic unbalance can be clearly separated.

Advantageously, the device provides 120 an immediate detection of a problem, a quantitative assessment for the correction and an automation of the measurement process.

2 shows a block diagram of a device 120 according to an embodiment of the present invention. In the device 120 it may be an embodiment of an in 1 shown device 120 for monitoring a wind turbine 100 act. The device 120 includes at least one device 230 to determine. Here is the device 230 trained to determine an imbalance information 126 using a rotation signal 124 to monitor to monitor the wind turbine 126 , The unbalance information represents this 126 an imbalance of the wind turbine. The turn signal 124 Depending on the embodiment, an angular velocity of a drive shaft of the wind power plant or, alternatively, a torque on the drive shaft.

In one embodiment, the device is 230 designed to determine, to determine a phase angle of the rotational signal to a reference zero point, wherein the imbalance information is determined using the phase angle. In this case, a phase position not equal to zero indicates an imbalance, wherein a reference position for the imbalance can be determined using the phase position.

In one embodiment, the device is 230 designed to determine, to determine a first Blattpassierfrequenz for the first rotor blade and a second Blattpassierfrequenz for the second rotor blade using the rotation signal. In this case, the imbalance information is determined using a phase relationship between the first sheet passing frequency and the second sheet passing frequency.

In one embodiment, the rotation signal comprises a first rotation angle signal as the course of a first reference point on the drive shaft and a second rotation angle signal as the course of a second reference point on the drive shaft. In this case, the first rotational angle signal represents a phase position of a first rotor rotational frequency of the first rotor blade.

The second rotational angle signal represents a second phase position of a second rotor rotational frequency of the second rotor blade.

In an alternative embodiment, the first rotational angle signal represents a first signal provided by a first sensor disposed on the first rotor blade at the first rotor blade and the second rotational angle signal comprises a second signal provided by a second sensor disposed on the second rotor blade at the second reference point.

In the in 2 illustrated embodiment, the device 120 for monitoring the wind turbine further optional interfaces and facilities. An interface 234 for reading is formed, a rotation signal 124 read. Optional is the interface 234 for reading further trained, a speed 236 a component of the wind turbine read. Optional is the interface 234 configured to read in a read-in a torque signal, a first rotation angle signal and a second rotation angle signal or a rotor speed of the rotor as a rotational speed of the component of the drive train for reading.

Optionally, the device comprises 120 for monitoring the wind turbine, a transformation device 238 , which is formed using the rotation signal 124 a frequency signal 240 provide. In an embodiment in which the device 120 a transformation device 238 includes, is the device 230 trained to determine the imbalance information 126 using the frequency signal 240 to investigate. In this case, an amplitude at at least one frequency or in a frequency range is compared with a predetermined threshold value.

In the in 2 illustrated embodiment, the device 120 for monitoring the wind turbine further an optional control device 242 formed, a control signal 244 to provide at least one pitch angle of the at least one rotor blade or to control a rotational angle of the rotor of the wind turbine.

In one embodiment, the device is 230 trained to determine the imbalance information 126 using the speed 236 to determine. That's the device 230 for determining optionally designed to determine the rotor speed of the rotor, the double rotor speed of the rotor or a meshing frequency of a gear stage of the drive train and to determine the unbalance information 126 to use.

Optionally, the device determines 230 for determining as a property of the frequency signal 236 an amplitude at a characteristic frequency.

3 shows a flowchart of a method 360 for monitoring a wind turbine according to an embodiment of the present invention. The wind turbine can be an embodiment of an in 1 shown wind turbine 100 act. The procedure 360 includes at least one step 362 determining an imbalance information representing an imbalance of the wind turbine using a rotation signal to monitor the wind turbine, the rotation signal representing an angular velocity and / or a torque on the drive shaft.

4 shows a simplified graphical representation of a phase angle 470 two signals 472 . 474 between two rotor blades according to an embodiment of the present invention. The signals 472 . 474 Depending on the exemplary embodiment, they represent a rotor rotational frequency, a blade passing frequency, a rotational angle or a torque of an associated rotor blade. It is in the in 4 On the left shown Cartesian coordinate system a signal 472 a first rotor blade and a signal 472 of a second rotor blade over time. The distance 470 represents the phase position 470 between the first signal 472 of the first rotor blade and the second signal 474 of the second rotor blade. In an exemplary embodiment which is not illustrated, this can be extended, for example, by a third signal of a third rotor blade, if it is a wind energy plant with a rotor comprising three rotor blades. If the rotor blades are arranged at an angle of 120 ° to each other, then the phase angle is 470 between two rotor speeds without imbalance or assembly error also 120 °. In the in 4 On the right of the Cartesian coordinate system, the abscissa represents the frequency and the ordinate represents the phase position. The illustrated curve 476 shows, for example, the phase angle between a first rotor blade and a second rotor blade. At a frequency that corresponds to the rotor's rotational frequency, the signal points 476 a significant amplitude. Other characteristic frequencies, such as twice the rotor rotational frequency or the meshing frequency, or a frequency range around the characteristic frequencies, shows the curve 476 Amplitudes whose height can be evaluated. The amplitude corresponds to the phase position.

An aerodynamic imbalance and / or a mass imbalance causes inter alia a different phase position of the rotor rotational frequency (1p) of the rotor blades from one another than 120 °. So shows 4 a phase angle of the 1p frequency between the rotor blades. The phase angle is accordingly dependent on the number of rotor blades of the rotor or the angle of the rotor blades to each other.

5 shows a simplified representation of a frequency signal 236 . 536 with a characteristic frequency 238 at twice the rotor rotational frequency according to an embodiment of the present invention. At the frequency signal 236 it may be an embodiment of an in 2 described frequency signal 236 act. In a Cartesian coordinate system, the abscissa shows the frequency and the ordinate the amplitude. As a waveform are two frequency signals 236 . 536 represented in the Cartesian coordinate system. This shows the first frequency signal 236 an imbalance and the second frequency signal 536 shows no imbalance. On the abscissa are three characteristic frequencies 238 marked: the rotor rotational frequency p or 1p, the double rotor rotational frequency 2p and a meshing frequency f _z . The waveforms of the two frequency signals 236 . 536 each have a rash in the range of the three mentioned characteristic frequencies 238 on. In this case, the highest amplitude in the range of the rotor rotational frequency p is observed. In the region of twice the rotor rotational frequency 2p, the signal characteristics of the two frequency signals 236 . 536 a significant difference in amplitude. This shows that this property can be used to detect an imbalance in the wind turbine.

A mass imbalance causes, inter alia, a vibration of the tower at right angles to the wind direction. Based on the phase position of this vibration can be close to the position of the center of gravity with respect to the axis of rotation, so that the positioning of the balancing weights can be determined.

An aerodynamic imbalance causes, inter alia, a vibration with a simple rotor rotational frequency. On the basis of the amplitude of this oscillation, it is possible to conclude, for example, the expression of a pitch angle adjustment of a rotor blade.

6 shows a simplified representation of a frequency signal 236 with a meshing frequency f _z as a characteristic frequency 238 according to an embodiment of the present invention. At the frequency signal 236 it may be an embodiment of an in 2 described frequency signal 236 act. As an example of a characteristic frequency 238 the meshing frequency f _{z is} selected. The frequency signal 236 has in the region of the meshing frequency f _{z on} a time varying amplitude. The variance of the amplitude is in 6 denoted by ΔA.

Among other things, a mass imbalance causes a cyclic change in the amplitude of the meshing frequency during one revolution. 6 shows a change ΔA in the amplitude of the meshing frequency f _z during one revolution.

7 shows a simplified representation of an amplitude of the meshing frequency f _z via a rotor rotation according to an embodiment of the present invention. The tooth engagement frequency f _z may be an exemplary embodiment of a tooth engagement frequency f _z described in the preceding figures. In a Cartesian coordinate system, a rotational position Ω of the rotor of a wind turbine is shown on the abscissa and an amplitude of a frequency signal at a characteristic frequency on the ordinate. In the Cartesian coordinate system, a waveform of a tooth meshing frequency f _{z is shown} via the rotational position Ω of the rotor of the wind turbine. The maximum of the amplitude during one revolution of the rotor provides information about which blade the additional mass is located on.

The exemplary embodiments shown are chosen only by way of example and can be combined with one another.

LIST OF REFERENCE NUMBERS

100

Wind turbine

102

tower

104

gondola

106

rotor

108

rotor blade

109

rotor hub

110

Rotor shaft, rotor axle, drive shaft

112

powertrain

114

transmission

116

gear stage

118

generator

120

Device for monitoring

122

sensor

124

Rotary signal, sensor information, course of the rotation angle

126

unbalance information

230

Device for determining

234

Interface for reading

236

rotation speed

238

transformation means

240

frequency signal

242

control device

244

control signal

360

Method of monitoring

362

Step of determining

470

phasing

472

first signal

474

second signal

476

Signal, waveform

p

Rotor rotational frequency

536

frequency signal

2p

double rotor speed

fz

Meshing frequency

Ω

rotary position

Claims (12)

Procedure ( 360 ) for monitoring a wind turbine ( 100 ), whereby the wind energy plant ( 100 ) a drive train ( 112 ) driving rotor ( 106 ) with a first rotor blade ( 108a ) and at least one second rotor blade ( 108b ), the method ( 360 ) comprises at least the following step: determining ( 362 ) one of an imbalance of the wind turbine ( 100 ) imbalance information ( 126 ) using a rotation signal ( 124 ) to the wind turbine ( 100 ), the rotation signal ( 124 ) an angular velocity and / or a torque on the drive shaft ( 110 ). Procedure ( 360 ) according to claim 1, wherein in step ( 362 ) of determining a phase position ( 470 ) of the rotary signal ( 124 ) is determined to a reference zero point, the unbalance information ( 126 ) using the phase position ( 470 ) is determined. Procedure ( 360 ) according to one of the preceding claims, wherein in step ( 362 ) of determining a first blade passing frequency for the first rotor blade ( 108a ) and a second Blattpassierfrequenz for the second rotor blade ( 108b ) using the rotation signal ( 124 ), the unbalance information ( 126 ) using a phase relationship ( 470 ) between the first sheet passing frequency and the second sheet passing frequency. Procedure ( 360 ) according to one of the preceding claims, in which the rotation signal ( 124 ) a first rotation angle signal ( 472 ) as the course of a first reference point on the drive shaft ( 110 ) and a second rotation angle signal ( 474 ) as the course of a second reference point on the drive shaft ( 110 ), wherein the first rotation angle signal ( 472 ) a phase position ( 470 ) of a first rotor rotational frequency of the first rotor blade ( 108a ) and the second rotation angle signal ( 474 ) a second phase position ( 470 ) a second rotor rotational frequency of the second rotor blade ( 108b ). Procedure ( 360 ) according to claim 4, wherein the first rotation angle signal ( 472 ) one of a at the first reference point on the first rotor blade ( 108a ) arranged first sensor ( 122 ) provided first signal ( 472 ) and the second rotation angle signal ( 474 ) one of the at the second reference point on the second rotor blade ( 108b ) arranged second sensor ( 122 ) provided second signal ( 474 ). Procedure ( 360 ) according to claim 5, wherein the first sensor ( 122 ) as a first Torque sensor and / or a first rotation angle sensor and / or a first acceleration sensor and / or a first magnetic sensor is formed and / or the second sensor ( 122 ) is formed as a second torque sensor and / or a second rotation angle sensor and / or a second acceleration sensor and / or a second magnetic sensor. Procedure ( 360 ) according to one of the preceding claims, with a step of reading the rotary signal ( 124 ) and / or the torque signal and / or the first rotational angle signal and / or the second rotational angle signal and / or the rotational speed of the component of the drive train ( 112 ) and / or a rotor speed of the rotor ( 106 ) as the speed of the component of the drive train ( 112 ). Procedure ( 360 ) according to one of the preceding claims, comprising a step of providing a control signal ( 250 ) for controlling at least one pitch angle of the at least one rotor blade ( 108 ) of the rotor ( 106 ) and / or providing a further control signal for controlling a rotational angle of the rotor ( 106 ) to correct an aerodynamic imbalance. Contraption ( 120 ) for monitoring a wind turbine ( 100 ), the device ( 120 ) Facilities for carrying out a method ( 360 ) according to one of the preceding claims. Wind energy plant ( 100 ) with a tower ( 102 ), one on the tower ( 102 ) arranged gondola ( 104 ), one at the gondola ( 104 ) arranged rotor ( 106 ) with a plurality of rotor blades ( 108 ) and with a device ( 120 ) according to claim 9, wherein the device ( 120 ) in the wind energy plant ( 100 ) is integrated. Computer program adapted to perform all steps of a procedure ( 360 ) according to one of the preceding claims.  Machine-readable storage medium with a computer program stored thereon according to claim 11.

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