Encapsulated wireless sensor device for mounting on a rotor blade

Abstract

The invention relates to an encapsulated wireless sensor device (1) for mounting on a rotor blade (2), the sensor device (1) being designed to detect vibrations of the rotor blade (2), in particular to detect deviations from a norm, and the sensor device (1) comprising the following: - at least one acoustic detection device (3) for detecting airborne sound and structure-borne sound; - at least one computing unit (4) for evaluating data detected by the detection device (3); - at least one internal communication unit (5); and, - an energy supply unit (8) for supplying the components of the sensor device (1).

Description

[0001] P25805pct

[0002] Encapsulated wireless sensor device for mounting on a rotor blade

[0003] The invention relates to an encapsulated wireless sensor device for mounting on a rotor blade, wherein the sensor device is designed to detect vibrations of the rotor blade, in particular to detect deviations from a standard behavior.

[0004] The possibility of acoustically monitoring a wind turbine rotor blade during operation is already known from the prior art. Methods intended to reduce the noise emissions of wind turbines are also known; see, for example, document WO 2010061255 A2.

[0005] Damage to rotor blades can lead to altered noise emissions and / or body-borne sound waves. Similarly, a damage event can be detected by measuring airborne and / or body-borne sound waves.

[0006] The effects of damage to rotor blades can be varied, ranging from merely reduced energy yields to dangerous operating conditions that require a rapid shutdown of the wind turbine in question.

[0007] This problem is solved with a sensor device of the type mentioned above, which according to the invention comprises the following:

[0008] - at least one acoustic detection device for detecting airborne sound and structure-borne sound,

[0009] - at least one computing unit for evaluating data captured by the recording device,

[0010] - at least one internal communication unit for the wireless transmission of data processed by the computing unit to an external communication unit, as well as

[0011] - a power supply unit for supplying electrical energy to the components of the sensor device, in particular the acoustic detection device, the computing unit and the internal communication unit, wherein the power supply unit

[0012] * an energy conversion unit for converting light and / or kinetic energy into electrical energy, as well as P25805pct

[0013] 2

[0014] * has an electrical energy storage device for storing the electrical energy converted by the energy conversion unit and for supplying the components of the sensor device.

[0015] The invention enables improved monitoring of the technical condition of a rotor blade. In particular, signs of aging can be detected based on the acoustic signature of a rotor blade. This allows for the optimization of maintenance intervals, maintenance measures, etc. Likewise, spontaneous damage or incidents, such as those that may occur during transport and / or installation of the rotor blade on the wind turbine, can be detected. The term "encapsulated" means that the sensor device can be operated without any externally accessible physical lines, i.e., without an external power supply or wired data transmission lines. The sensor device can be installed in a closed housing, which is preferably designed to protect against the elements.

[0016] Deviations from normal behavior can occur, for example, due to excessive stress (fall, impact), which can cause adhesive joints inside a rotor blade to fail. This leads to changes in the rotor blade's natural resonance, meaning that altered natural modes can be observed.

[0017] Furthermore, cracks could form inside the rotor blade, whereby, under further mechanical stress (rotation, transport), crack edges can rub against each other and generate noise in the air and on the structure (measurable as structure-borne sound).

[0018] Furthermore, mechanical damage can occur due to external influences, e.g., damage from a collision with a truck during transport and / or assembly. A hole in the rotor blade, if large enough, can also be detected by a change in vibration behavior.

[0019] Furthermore, the changing influence of wind (natural, due to movement or flow during rotation) can be detected, for example by detecting altered noises, since the wind entering the rotor blade can excite it as a resonance chamber.

[0020] The microphone can be any type of airborne transducer (electrodynamic transducer, electret microphone, condenser microphone, MEMS microphone, optical MEMS microphone). P25805pct

[0021] 3

[0022] Here, optimal decoupling from structure-borne noise can even be advantageous. An array arrangement can be beneficial (controllable directivity).

[0023] The structure-borne sound sensor should be mechanically coupled to the blade as effectively as possible while minimizing its overall mass. Adhesive bonding with a very hard material (typically 2-component epoxies, similar to rotor blade material) is recommended for this purpose.

[0024] Signal patterns perceptible via structure-borne sound can also be detected and verified in modified form as airborne sound signatures, albeit with a time delay. The same physical event leads to structure-borne sound (with corresponding propagation speed, frequency-dependent attenuation, and reflections at media boundaries) and to airborne sound. By capturing the acoustic signatures, complex, frequency- and distance-dependent sound propagation behaviors of critical areas of the rotor blade can be mapped, and relevant deviations can be quickly identified. Changes in the speed of sound or sudden echoes / delays can also indicate new structural damage.

[0025] To save energy, it may be provided that deviations from normal behavior are detected and that data on deviations from the normal are transmitted primarily or exclusively - in addition to a small amount of data that merely indicates the correct functioning of the sensor device.

[0026] Particularly when multiple sensor devices are installed on several wind turbines, it is possible to mutually compare and verify information by comparing it with the known mounting positions of the sensor devices. For example, the frequency spectrum signature of each wind turbine, also known as the wind turbine signature, can be recorded and monitored and compared with the wind turbine signatures of the other wind turbines in the wind farm, with changes over time being detected to indicate a detrimental condition of a wind turbine.

[0027] Furthermore, it can be provided that the sensors calibrate themselves alternately by receiving noise reference data from at least one additional acoustic sensor, which is placed on the at least one reference point for at least the duration of the calibration, and wherein the corresponding calculated noise level is compared with the corresponding noise reference data, and wherein the algorithm that performs the P25805pct

[0028] The first and second data streams are processed in such a way that the differences between the calculated noise level and the noise reference data are minimized.

[0029] In particular, the sensor device may also include a multi-axis accelerometer. The multi-axis sensor enables measurement in any spatial direction.

[0030] Furthermore, it may be provided that the acoustic detection device includes a microphone for detecting airborne sound and at least one acoustic sensor specifically designed for detecting structure-borne sound.

[0031] In particular, it may be provided that the acoustic detection device has two or more acoustic sensors designed to detect structure-borne sound, wherein these acoustic sensors are arranged at least 10 m apart in a state mounted on the rotor blade.

[0032] Furthermore, it may be provided that the sensor device also has a multi-axis gyro sensor.

[0033] In particular, the sensor device may also include a multi-axis magnetic field sensor. The magnetic field sensor can be used for position determination.

[0034] Furthermore, the internal communication unit can be configured for wireless communication with another internal communication unit of an identical sensor device. In this way, networking multiple sensor devices can create a swarm intelligence that allows for even more precise determination of damage to one or more rotor blades.

[0035] In particular, it may be provided that the internal communication unit has a mobile communication connection for exchanging data via mobile network.

[0036] Furthermore, it may be provided that the sensor device includes a photovoltaic module for supplying the electrical energy storage system with electrical energy.

[0037] In particular, the sensor device may be designed to include a GPS module for

[0038] Determination of the 3D position of the sensor device. For example, the location of a P25805pct can also be determined.

[0039] 5. Any damage event that may be recorded must be documented and reported. For example, a damage event could occur during the manufacturing of the rotor blade, during loading for transport, during transport, during assembly, or during operation of the rotor blade. By comparing the recorded time of a damage event with its location, it can be clearly determined in advance which area of ​​responsibility the damage event falls under.

[0040] Furthermore, the invention relates to a sensor system comprising at least one sensor device and an external receiving unit for receiving the data transmitted by the sensor device.

[0041] In particular, it can be provided that at least one sensor device is integrated into a rotor blade, especially in the blade root. The blade root is the part of the rotor blade where the greatest loads act and where, in particular, the force is transmitted to the hub. The transitions from metal to glass fiber reinforced plastic, which are frequently found there and are also critical, can be monitored with particular accuracy in this way. This part of the blade is especially important for monitoring; it is the easiest to access for assembly / maintenance during operation and is subjected to the least centrifugal force. A receiving unit ("data recording") can also preferably be mounted here.

[0042] Furthermore, it may be provided that at least one further sensor device is provided, which is mounted on the same rotor blade at a distance from a first sensor device, wherein the distance is preferably between lm and 100m along the longitudinal extent of the rotor blade.

[0043] In particular, it may be provided that at least one further sensor device is provided, which is mounted on a different rotor blade than a first sensor device.

[0044] Furthermore, it can be provided that the rotor blades have the same longitudinal extent and that at least one sensor device is arranged at the same positions on each rotor blade.

[0045] In particular, it may be provided that the computing unit of a sensor device and / or an external computing unit are configured to receive data from the sensor devices P25805pct

[0046] 6. To compare the recorded data and, depending on the result of the comparison, to initiate the output of error and / or warning messages.

[0047] Furthermore, the sensor system 17 may include at least one or more additional sensor units 3' mounted on at least one rotor blade 2, wherein these sensor units 3' are configured for communication with the at least one sensor device 1 and / or the external receiving unit 7, and wherein each sensor unit 3' is configured solely for measuring structure-borne sound and not for measuring airborne sound. That is, they are free of airborne sound sensors and therefore each has only one structure-borne sound sensor.

[0048] Furthermore, the invention relates to a wind turbine comprising a rotor blade with at least one sensor device according to the invention. The invention also relates to a wind farm comprising several wind turbines with several sensor devices and / or sensor systems according to the invention.

[0049] Furthermore, the invention relates to a method for monitoring the condition of a rotor blade of a wind turbine using at least one sensor device and / or a sensor system according to one of the preceding claims, comprising the following steps: a) attaching at least one sensor device to a rotor blade, b) activating the at least one sensor device to detect vibrations of the rotor blade.

[0050] The activation can be continuous, i.e., without any intermediate time gaps, in order to allow for uninterrupted recording of rotor blade vibrations.

[0051] In particular, it may be provided that at least one sensor device is activated, encompassing the rotor blade in accordance with step b), at the latest upon commissioning of a wind turbine.

[0052] Furthermore, it may be provided that at least one sensor device is activated during the manufacturing process, in any case before delivery of the rotor blade, in accordance with step b). P25805pct

[0053] 7

[0054] The data is collected while the system is active and can be automatically analyzed. Installation can be carried out at the factory, enabling seamless monitoring from the removal of the rotor blade through its mounting on the wind turbine to the operation of the wind turbine.

[0055] In other words, and without limiting the scope of the invention, it can also be described as follows: A combination of airborne and structure-borne sound measurement on rotor blades for damage detection and condition monitoring. For this purpose, a first sensor node (or sensor device) can be provided in the blade root, comprising at least one microphone, a power supply with a mechanical harvester and energy storage device, optionally a single- or multi-axis accelerometer, and a single- or multi-axis gyroscope. This first sensor node has an energy storage device that can supply it with energy for at least several months and can be charged via an energy conversion unit. This first sensor node has a radio interface for time-synchronized communication with one or more other sensor nodes or an external interface. The first sensor node can have a GPS receiver for determining its position.Additional sensor nodes may be provided, which can be connected to wireless, energy-autonomous sensors on the leaf surface. Each node may also be equipped with photovoltaic or mechanical harvesters and energy storage devices, and each node also has at least one single- or multi-axis accelerometer, one single- or multi-axis gyroscope, and a radio interface. These additional sensor nodes are located spatially separate from the first sensor node and are equipped with a data processing and storage unit capable of storing the data provided by the sensor nodes for several months, with or without energy storage. This data processing and storage unit includes a cellular communication module that allows the collected sensor node data to be transmitted to a central data collection point.

[0056] The sensor devices can be used for operation and condition monitoring of the rotor blade during operation, but also beforehand, e.g., Application 1: Monitoring of rotor blade handling from the blade production plant to the commissioning of the wind turbine – including immediate detection of damage-relevant events and damage, storage of data, position and timestamp, and, if necessary, prevention of the installation of damaged blades; Application 2: Characterization of the structural-mechanical and acoustic properties of the individual rotor blade to reduce uncertainty in blade monitoring in the P25805pct

[0057] 8

[0058] Operation and to shorten the subsequent learning time of signal-based, e.g. acoustic, measurement methods; Application 3: Detection of leaf damage and leaf damage progression during ongoing operation

[0059] For this purpose, measurement data from the first and subsequent sensor nodes (or sensor devices) can be correlated and their effects compared with internal or other known data; the measurement data from other rotor blades also undergoing transport are compared with each other. This can also serve to identify critical locations or factors along the transport chain (e.g., excessively jerky lifting, a pothole, a defective crane) and eliminate such causes for subsequent transports on the same route. In the simplest case, the comparison can be carried out, for example, by recording the natural frequencies of the rotor blade and / or recording maximum values ​​of vibrations / sound levels. For example, a damage event can be identified by an increased maximum value of recorded vibrations / sound levels, whereby, for example,After damage has occurred, the natural frequency of the rotor blade may be altered, making the damage event and its impact even more clearly determinable. In particular, more complex analyses allow, for example, spectra to be recorded periodically over short periods and correlated with each other (temporally and spatially). This offers the following advantages: a comprehensive overview of the entire rotor blade handling process, including events measurable acoustically or through structure-borne sound within the rotor blade; data collection for similar / future transports; identification and prevention of situations damaging the rotor blade during the handling process; and insights into any pre-existing damage.

[0060] The invention is explained in more detail below with reference to an exemplary and non-limiting embodiment, which is illustrated in the figures. These show

[0061] Figure 1 shows a schematic representation of a rotor blade with sensor devices attached to it.

[0062] Figure 2 shows a schematic representation of a sensor device according to the invention.

[0063] Figure 3 shows a schematic representation of an energy supply unit consisting of an energy conversion unit and an electrical energy storage device, P25805pct

[0064] 9

[0065] Figure 4a shows a sensor device according to Fig. 2 additionally with an acceleration sensor,

[0066] Figure 4b shows a sensor device according to Fig. 2 additionally with a multi-axis gyro sensor,

[0067] Figure 4c shows a sensor device according to Fig. 2 additionally with a magnetic field sensor,

[0068] Figure 4d shows a sensor unit that only has a structure-borne sound sensor and no microphone,

[0069] Figure 5 shows a rotor blade with several sensor devices with structure-borne sound transducers.

[0070] Figure 6 shows two sensor devices communicating with each other via their internal communication facilities.

[0071] Figure 7 shows a sensor device with an internal communication device suitable for mobile communications,

[0072] Figure 8 shows an energy supply unit consisting of an energy conversion unit and an electrical energy storage device.

[0073] Figure 9 shows a sensor system comprising a sensor device that sends externalized data to an external receiver,

[0074] Figure 10 shows a rotor blade with a sensor device in the area of ​​the blade root,

[0075] Figure 11 shows a rotor blade with two sensor devices mounted on it,

[0076] Figure 12 shows two rotor blades with sensor devices, which are arranged, for example, in the area of ​​the blade root.

[0077] Figure 13 shows two rotor blades with sensor devices at a position of equal longitudinal extent.

[0078] Figure 14 shows a schematic representation of an exemplary wind turbine, and

[0079] Figure 15 shows a schematic representation of an exemplary wind farm.

[0080] In the following figures, unless otherwise indicated, the same reference symbols denote the same features. P25805pct

[0081] 10

[0082] Figure 1 shows a schematic representation of a rotor blade 2 with sensor devices 1 attached to it.

[0083] Figure 2 shows a schematic representation of a sensor device 1 according to the invention. The encapsulated wireless (i.e., no external cables) sensor device 1 for mounting on a rotor blade 2 is designed to detect vibrations of the rotor blade 2, in particular to detect deviations from normal behavior. It comprises at least one acoustic detection device 3 for detecting airborne and structure-borne sound, at least one processing unit 4 for evaluating data acquired by the detection device 3, at least one internal communication unit 5 for wirelessly transmitting data 6 processed by the processing unit 4 to an external communication unit 7, and a power supply unit 8 for supplying electrical energy to the components of the sensor device 1, in particular the acoustic detection device 3, the processing unit 4, and the internal communication unit 5.The acoustic detection device 3 has a microphone 12 for detecting airborne sound and at least one acoustic sensor 13 which is specifically designed for detecting structure-borne sound.

[0084] Figure 3 shows a schematic representation of an energy supply unit 8, wherein the energy supply unit 8 comprises an energy conversion unit 9 for converting light and / or kinetic energy into electrical energy, and an electrical energy storage unit 10 for storing the electrical energy converted by the energy conversion unit 8 and for supplying the components of the sensor device 1.

[0085] Figure 4a shows a sensor device 1 according to Fig. 2 additionally with an acceleration sensor 11. Figure 4b shows a sensor device according to Fig. 2 additionally with an acoustic detection device comprising a microphone and a structure-borne sound transducer.

[0086] Figure 4b shows a sensor device 1 according to Fig. 2 additionally with a multi-axis gyro sensor 14. Figure 4c shows a sensor device 1 according to Fig. 2 additionally with a magnetic field sensor 15.

[0087] Figure 4d shows a sensor unit 3' that has only a structure-borne sound sensor 13 and no microphone. It may have additional sensors for determining its position, or it may have the structure-borne sound sensor 13 as the only sensor. P25805pct

[0088] 11

[0089] Figure 5 shows a rotor blade 2 with several sensor units 3' with structure-borne sound transducers 13. The acoustic detection device 3 can also have two or more acoustic sensors 13 configured to detect structure-borne sound, wherein these acoustic sensors 13 are arranged at least 10 m apart when mounted on the rotor blade 2. The same can be achieved by using several sensor units 3'.

[0090] Fig. 6 shows that the internal communication unit 5 can also be configured for wireless communication with another internal communication unit 5 of an identical sensor device 1.

[0091] Fig. 7 illustrates that the internal communication unit 5 can have a mobile communication connection 16 for exchanging data via mobile communication. Fig. 8 illustrates that the sensor device 1 can have a photovoltaic module for supplying the electrical energy storage device 10 with electrical energy. The sensor device can, for example, be arranged at an exposed position on a rotor blade and be at least partially integrated into the rotor blade surface or arranged on its outer surface.

[0092] Furthermore, it may be provided that the sensor device 1 has a GPS module for determining the 3D position of the sensor device 1.

[0093] Fig. 9 shows a sensor system 17 comprising at least one sensor device 1 and an external receiving unit 7 for receiving the externalized data 18 transmitted by the sensor device 1. Fig. 10 shows that the at least one sensor device 1 can be integrated into a rotor blade 2, in particular in the blade root 19 of the rotor blade 2.

[0094] Fig. 11 shows that at least one further sensor device 1 is provided, which is mounted on the same rotor blade at a distance from a first sensor device 1, the distance preferably being between 1 m and 100 m along the longitudinal extent of the rotor blade. Fig. 12 shows that at least one further sensor device 1 can be provided, which can be mounted on a different rotor blade 2 than another sensor device 1. The rotor blades 2 can have the same longitudinal extent, and it can be provided that the sensor devices are arranged at the same positions on the rotor blades 2. If the rotor blades 2 are transported together or in quick succession along the same route, special events during transport can also be compared for plausibility, such as when both rotor blades 2 experience increased P25805pct.

[0095] 12

[0096] Vibrations, oscillations, or changes in position may be perceived on certain sections of the road or loading ramps. Of course, the rotor blades can be mounted on the same wind turbine or on different wind turbines.

[0097] The sensor system 17 can have at least one or more further sensor units 18 mounted on at least one rotor blade 2, wherein these sensor units 18 are configured to communicate with the at least one sensor device 1 and / or the external receiving unit 7, and wherein each sensor unit 18 is configured solely for measuring structure-borne sound and not for measuring airborne sound.

[0098] Furthermore, the invention relates to a method for monitoring the condition of a rotor blade 2 of a wind turbine using at least one sensor device 1 and / or a sensor system 17 according to one of the preceding claims, comprising the following steps: a) attaching at least one sensor device 1 to a rotor blade 2, b) activating the at least one sensor device 1 to detect vibrations of the rotor blade 2.

[0099] In particular, it may be provided that the at least one sensor device 1 is activated no later than upon commissioning of a wind turbine encompassing the rotor blade 2 in accordance with step b). Furthermore, it may be provided that the at least one sensor device 1 is activated in accordance with step b) during the manufacturing process, in any case before delivery of the rotor blade 2.

[0100] Figure 14 shows a schematic representation of an exemplary wind turbine 21a, in which sensor devices 1, sensor units 3' and / or sensor systems 17 can be arranged at different positions.

[0101] The invention also relates to a wind farm 20 comprising several wind turbines 21a to 21d with several sensor devices 1, sensor units 3' and / or sensor systems 17 according to the invention, which can be arranged on rotor blades not shown in detail in the figures and / or on other structures of a wind turbine 21a to 21d, as shown in Figure 15. In practice, the number of wind turbines can of course be significantly higher than that shown only schematically. P25805pct

[0102] 13

[0103] Furthermore, by using the aforementioned sensor devices 1, sensor units 3' and / or sensor systems 17, a method for the computational monitoring, evaluation and control of sound emissions from a wind farm 20 can be implemented. It can be provided that the wind farm 20 comprises at least two wind turbines 21a, 21b, 21c, 21d, wherein at least one wind turbine 21a, 21b, 21c, 21d comprises at least one sensor device 1, sensor unit 3' and / or sensor system 17.A digital map of the wind farm 20 can be created, wherein the digital map represents its spatial arrangement with respect to at least one reference point representing a point in space, including at least one threshold value for the noise level for each reference point, and this digital map can be made available to a processing unit, wherein the digital map preferably also includes information about the topographic landscape of the area of ​​the wind farm 20 and its surroundings.Furthermore, a reference scenario can be created by supplying the processing unit with a first data stream of wind turbine operating data from each wind turbine, wherein the wind turbine operating data includes at least two of the following data: wind speed recorded at wind turbine 21a, 21b, 21c, 21d; pitch angle of the rotor blades 2; wind direction; orientation of wind turbine 21a, 21b, 21c, 21d with respect to the wind direction; power output of wind turbine 21a, 21b, 21c, 21d; operating noise mode and / or power mode of wind turbine 21a, 21b, 21c, 21d. The processing unit can be supplied with a second data stream of noise emission data and / or structure-borne sound data recorded by devices 1, 3, and 17, and processed and evaluated by an algorithm using the processing unit.

[0104] The frequency spectrum signature of each wind turbine 21a, 21b, 21c, 21d can be recorded and monitored. It can be compared with the signatures of the other wind turbines 21a, 21b, 21c, 21d of the wind farm 20, and changes over time can be recorded to indicate a harmful condition of a wind turbine 21a, 21b, 21c, 21d.

[0105] The invention is not limited to the embodiments shown, but is defined by the entire scope of protection of the claims. Individual aspects of the invention or the embodiments can also be taken up and combined with one another. P25805pct

[0106] 14

[0107] Any reference numerals in the claims are exemplary and serve only to make the claims easier to read, without limiting them.

Claims

P25805pct 15 PATENT CLAIMS 1. Encapsulated wireless sensor device (1) for mounting on a rotor blade (2), wherein the sensor device (1) is configured to detect vibrations of the rotor blade (2), in particular to detect deviations from a standard behavior, wherein the sensor device (1) comprises the following: - at least one acoustic detection device (3) for detecting airborne sound and structure-borne sound, - at least one computing unit (4) for evaluating data acquired by the recording device (3), - at least one internal communication unit (5) for wireless transmission of data (6) processed by the computing unit (4) to an external communication unit (7), and a power supply unit (8) for supplying electrical energy to the components of the sensor device (1), in particular the acoustic detection device (3), the computing unit (4) and the internal communication unit (5), wherein the power supply unit (8) * an energy conversion unit (9) for converting light and / or kinetic energy into electrical energy, as well as * has an electrical energy storage device (10) for storing the electrical energy converted by the energy conversion unit (8) and for supplying the components of the sensor device (1).

2. Sensor device (1) according to claim 1, wherein the sensor device (1) further comprises a multi-axis acceleration sensor (11).

3. Sensor device (1) according to one of the preceding claims, wherein the acoustic detection device (3) comprises a microphone (12) for detecting airborne sound and at least one acoustic sensor (13) which is specifically designed for detecting structure-borne sound. P25805pct 16 4. Sensor device (1) according to one of the preceding claims, wherein the acoustic detection device (3) comprises two or more acoustic sensors (13) configured to detect structure-borne sound, wherein these acoustic sensors (13) are arranged at least 10 m apart in a state mounted on the rotor blade (2).

5. Sensor device (1) according to one of the preceding claims, wherein the The sensor device (1) also includes a multi-axis gyro sensor (14).

6. Sensor device (1) according to one of the preceding claims, wherein the The sensor device (1) also includes a multi-axis magnetic field sensor (15).

7. Sensor device (1) according to one of the preceding claims, wherein the internal communication unit (5) is further configured for wireless communication with another internal communication unit (5) of an identical sensor device (1).

8. Sensor device (1) according to one of the preceding claims, wherein the internal communication unit (5) has a mobile communication connection (16) for exchanging data via mobile communication.

9. Sensor device (1) according to one of the preceding claims, wherein the sensor device (1) comprises a photovoltaic module for supplying the electrical energy storage device (10) with electrical energy.

10. Sensor device (1) according to one of the preceding claims, wherein the sensor device (1) comprises a GPS module for determining the 3D position of the sensor device (1).

11. Sensor system (17) comprising at least one sensor device (1) according to one of the preceding claims, and an external receiving unit (7) for receiving the data (18) transmitted by the sensor device (1).

12. Sensor system (17) according to claim 11, wherein the at least one sensor device (1) is integrated into a rotor blade (2), in particular in the blade root (19) of the rotor blade (2). P25805pct 17 13. Sensor system (17) according to claim 11 or 12, wherein at least one further sensor device (1) is provided which is mounted on the same rotor blade at a distance from a first sensor device (1), wherein the distance is preferably between lm and 100m along the longitudinal extent of the rotor blade.

14. Sensor system (17) according to one of claims 11 to 13, wherein at least one further sensor device (1) is provided which is mounted on a different rotor blade (2) than a first sensor device (1).

15. Sensor system (17) according to claim 14, wherein the rotor blades (2) have the same longitudinal extent and at least one sensor device (1) is arranged at the same positions on the rotor blades (2).

16. Sensor system (17) according to one of claims 11 to 15, wherein the computing unit (4) of a sensor device (1) and / or an external computing unit (4) are configured to compare data acquired by the sensor devices (1) and, depending on the result of the comparison, to initiate the output of error and / or warning messages.

17. Sensor system (17) according to one of claims 11 to 15, wherein the sensor system (17) comprises at least one or more further sensor units (3') mounted on at least one rotor blade (2), wherein these sensor units (3') are configured to communicate with the at least one sensor device (1) and / or the external receiving unit (7), and wherein each sensor unit (3) is configured solely for measuring structure-borne sound and not for measuring airborne sound.

18. Method for monitoring the condition of a rotor blade (2) of a wind turbine (21a to 21d) using at least one sensor device (1) and / or a sensor system (17) according to one of the preceding claims, comprising the following steps: a) attaching at least one sensor device (1) to a rotor blade (2), b) activating the at least one sensor device (1) to detect vibrations of the rotor blade (2). P25805pct 18 19. Method according to claim 18, wherein the at least one sensor device (1) is activated at the latest upon commissioning of a wind turbine comprising the rotor blade (2) according to step b).

20. Method according to claim 18, wherein the at least one sensor device (1) is activated during the manufacturing process, in any case before delivery of the rotor blade (2), according to step b).

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