System and method for inspecting blade

Abstract

To detect damage to blades in a wind power generation device.SOLUTION: A blade inspection system comprises a receiving unit that receives radio waves from a GNSS satellite that has passed through blades of a wind power generation device, and a detection unit that detects damage to the blades based on parameters of the received radio waves.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a system and method for inspecting blades in a wind power generation device.

Background Art

[0002] A wind power generation device rotates blades by wind power and converts this rotation into electric power. Since the blades can deteriorate, inspection is necessary.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to detect damage to blades in a wind power generation device.

Means for Solving the Problems

[0005] By way of example, the following solution means are provided.

[0006] [1] A receiving unit that receives radio waves from GNSS satellites that have passed through the blades of a wind power generation device, A blade inspection system comprising: a detection unit that detects damage to the blade based on the specifications of the received radio waves.

[0007] [2] The specifications of the radio waves are the amplitude, phase, or polarization plane of the received radio waves. The blade inspection system according to [1].

[0008] [3] A radio wave transmitting device that transmits radio waves, A receiving unit that receives radio waves from the radio wave transmitting device that have passed through the blades of a wind power generation device, A detection unit that detects damage to the blade based on the specifications of the received radio waves, and The specifications are amplitude, a blade inspection system.

[0009] [4] A radio wave transmitting device that transmits radio waves, A receiving unit that receives radio waves from the radio wave transmitting device that have passed through the blades of a wind power generation device, A detection unit that detects damage to the blade based on the specifications of the received radio waves, and The specifications are phase, a blade inspection system.

[0010] [5] A radio wave transmitting device that transmits radio waves, A receiving unit that receives radio waves from the radio wave transmitting device that have passed through the blades of a wind power generation device, A detection unit that detects damage to the blade based on the specifications of the received radio waves, and The specifications are polarization plane, a blade inspection system.

[0011] [6] The radio wave transmitting device is mounted on a drone, the blade inspection system according to any one of [3] to [5].

[0012] [7] The frequency of the radio waves is different from the frequency of GNSS satellites, the blade inspection system according to any one of [3] to [6].

[0013] [8] The receiving unit receives the radio waves that have passed through the blade and the radio waves that have not passed through the blade, The detection unit normalizes the specifications of the radio wave transmitted through the blade with the specifications of the radio wave that has not passed through the blade, and detects damage to the blade based on the normalized specifications. The blade inspection system according to any one of [1] to [7].

[0014] [9] The wind power generation device is provided with a first blade and a second blade as the blades. The detection unit compares the specifications of the radio wave transmitted through the first blade with the specifications of the radio wave transmitted through the second blade, and detects damage to the first blade and / or the second blade. The blade inspection system according to any one of [1] to [8].

[0015]

[10] The detection unit compares the specifications of the radio wave transmitted through the blade at a certain time with the specifications of the radio wave transmitted through the blade at another time, and detects damage to the blade. The blade inspection system according to any one of [1] to [8].

[0016]

[11] A first step of receiving a radio wave from a GNSS satellite transmitted through a blade of a wind power generation device; A second step of detecting damage to the blade based on the specifications of the received radio wave. A blade inspection method including the above steps.

[0017]

[12] A first step of receiving a radio wave from a radio wave transmitting device transmitted through a blade of a wind power generation device; A second step of detecting damage to the blade based on the amplitude of the received radio wave. A blade inspection method including the above steps.

[0018]

[13] A first step of receiving a radio wave from a radio wave transmitting device transmitted through a blade of a wind power generation device; A second step of detecting damage to the blade based on the phase of the received radio wave. A blade inspection method including the above steps.

[0019]

[14] A first step of receiving radio waves from a radio wave transmission device that has passed through the blade of a wind power generation device; A blade inspection method including a second step of detecting damage to the blade based on the axial ratio of the received radio waves.

[0020]

[15] In the first step, the radio waves transmitted through the rotating blade are received. The blade inspection method according to any one of

[11] to

[14] . [Advantages of the Invention]

[0021] Damage to the blade in a wind power generation device can be detected. [Brief Description of the Drawings]

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0023] Hereinafter, embodiments according to the present invention will be specifically described with reference to the drawings.

[0024] FIG. 1 is a diagram for explaining an inspection method of the blade 2 in the wind power generation device 1. The present invention receives radio waves from a radio wave source 10 that has passed through the blade 2 and detects damage to the blade 2 based on the specifications of the received radio waves. The reception of radio waves and the detection of damage are performed, for example, by a blade inspection system 20 arranged on the nacelle 3 of the wind power generation device 1.

[0025] Specifically, when the blade 2 crosses a line connecting the radio wave source 10 and the blade inspection system 20 (hereinafter referred to as the "baseline"), forward scattering (such as Rayleigh scattering, Mie scattering, and geometric scattering) occurs in the radio wave. Due to this forward scattering, various parameters such as the amplitude, phase, and polarization plane (e.g., the axial ratio of polarization) of the radio wave change. As a result, the blade inspection system 20 receives the radio wave whose parameters have changed due to the transmission of the blade 2.

[0026] The changes in the parameters are different between the case where the blade 2 has damage (e.g., erosion, crack, lightning strike mark) and the case where there is no damage. Therefore, the damage of the blade 2 can be detected based on the parameters of the received radio wave. This will be described more specifically below.

[0027] (First Embodiment) FIG. 2 is a schematic block diagram of the blade inspection system 20 according to the first embodiment. In this embodiment, the GNSS (Global Navigation Satellite System) satellite 11 is used as the radio wave source 10 in FIG. 1.

[0028] The GNSS satellite 11 is GPS, GLOSNASS, Galileo, BeiDou, QZSS, etc., and is respectively in orbits such as IGSO (Inclined Geosynchronous Orbi) and MEO (Medium Earth Orbit), and transmits radio waves in a spread spectrum method. The position of the GNSS satellite 11 at each time is known. Therefore, the position of the GNSS satellite 11 at each time when viewed from above at a predetermined latitude, longitude, and altitude (also called SkyPlot) is also known.

[0029] A line connecting the blade inspection system 20 (antenna 211 described later) and the position of the GNSS satellite 11 at each time serves as a baseline. Since the GNSS satellite 11 moves, the baseline changes every moment. Given that the SkyPlot is known, the blade inspection system 20 is also arranged at a predetermined latitude, longitude, and altitude, and the position of the blade 2 at each time is also known, it is possible to determine whether the blade 2 crosses the baseline at each time and, if so, which part of the blade 2 it crosses. As the blade 2 rotates and the GNSS satellite 11 moves, radio waves from the GNSS satellite 11 will pass through various parts of the blade 2, enabling inspection of various parts of the blade 2.

[0030] The blade inspection system 20 in Fig. 2 includes a receiving unit 21 that receives radio waves from the GNSS satellite 11, and a detecting unit 22 that detects damage to the blade 2 based on the specifications of the received radio waves.

[0031] The receiving unit 21 includes an antenna 211, a front end 212, and a correlation processing unit 213.

[0032] The antenna 211 receives radio waves from the GNSS satellite 11. Specifically, when the blade 2 crosses the baseline, the antenna 211 receives radio waves from the GNSS satellite 11 that have passed through the blade 2. When the blade 2 does not cross the baseline, the antenna 211 receives radio waves from the GNSS satellite 11 that have not passed through the blade 2.

[0033] The antenna 211 may include an antenna 2111 that receives horizontally polarized radio waves and an antenna 2112 that receives vertically polarized radio waves. In this case, the receiving unit 21 has an antenna switching device 2114 that switches which of the antennas 2111 and 2112 receives the radio waves.

[0034] The front end 212 converts the radio waves received by the antenna 211 into electrical signals and amplifies or frequency-converts them as necessary.

[0035] The correlation processing unit 213 performs correlation processing on the electrical signal from the front end 212 and performs despreading. By performing the correlation processing, even if the radio wave from the GNSS satellite 11 is weak, the electrical signal can be confirmed. The electrical signal after the correlation processing is input to the detection unit 22.

[0036] The detection unit 22 includes an amplitude measurement unit 221, a phase measurement unit 222, a polarization plane measurement unit 223, a storage unit 224, and a determination unit 225. Some or all of these may be realized by a processor executing a predetermined program.

[0037] The amplitude measurement unit 221 measures the amplitude of the radio wave from the GNSS satellite 11 based on the electrical signal from the receiving unit 21. The amplitude measurement unit 221 preferably normalizes the amplitude of the radio wave transmitted through the blade 2 with the amplitude of the radio wave not transmitted through the blade 2. The measured amplitude is stored in the storage unit 224. A detailed processing example of the amplitude measurement unit 221 will be described later.

[0038] The phase measurement unit 222 measures the phase of the radio wave from the GNSS satellite 11 based on the electrical signal from the receiving unit 21. The phase measurement unit 222 preferably normalizes the phase of the radio wave transmitted through the blade 2 with the phase of the radio wave not transmitted through the blade 2. The measured phase is stored in the storage unit 224.

[0039] The polarization plane measurement unit 223 transmits a control signal for switching which of the antennas 2111 and 2112 receives the radio wave to the antenna switching device 2114. Then, the polarization plane measurement unit 223 measures the polarization plane of the radio wave from the GNSS satellite 11 based on the electrical signal from the receiving unit 21. As a specific example, the polarization plane measurement unit 223 compares the polarization plane of the signal when the radio wave is received by the antenna 2111 with the polarization plane of the signal when the radio wave is received by the antenna 2112 and calculates the axial ratio. The polarization plane measurement unit 223 preferably normalizes the polarization plane (axial ratio) of the radio wave transmitted through the blade 2 with the polarization plane (axial ratio) of the radio wave not transmitted through the blade 2. The measured polarization plane is stored in the storage unit 224.

[0040] The determination unit 225 determines whether there is damage to the blade 2 based on the specifications of the measured radio wave, that is, the amplitude, phase, and / or polarization plane. The determination unit 225 may determine what kind of damage exists in the blade 2. An example of the process by the determination unit 225 will be described later.

[0041] FIG. 3 is a flowchart showing an example of the process by the amplitude measurement unit 221. First, the amplitude measurement unit 221 determines whether the radio wave from the GNSS satellite 11 received at the time of measurement has passed through the blade 2 (step S1). That is, as described above, since the SkyPlot is known, the blade inspection system 20 is arranged at a predetermined latitude, longitude, and altitude, and the position of the blade 2 at each time is also known, it is possible to grasp whether the blade 2 crosses the baseline at the measurement time. When the blade 2 crosses the baseline, the radio wave that has passed through the blade 2 is received.

[0042] If the radio wave has not passed through the blade 2 (NO in step S1), the amplitude measurement unit 221 measures the amplitude of the radio wave that has not passed through the blade 2 based on the electrical signal from the receiving unit 21 (step S2). If necessary, the measured amplitude is stored in the storage unit 224.

[0043] If the radio wave has passed through the blade 2 (YES in step S1), the amplitude measurement unit 221 measures the amplitude of the radio wave that has passed through the blade 2 based on the electrical signal from the receiving unit 21 (step S3). Then, the amplitude measurement unit 221 normalizes the amplitude of the radio wave that has passed through the blade 2 using the amplitude of the radio wave that has not passed through the blade 2 calculated in step S2 (step S4). The normalized amplitude is stored in the storage unit 224 (step S5).

[0044] The above processes are repeated, and the (normalized) amplitude at each time is stored in the storage unit 224.

[0045] FIG. 4 is a diagram schematically showing an example of the relationship between the amplitude A measured by the amplitude measurement unit 221 and the time t. In this example, attention is paid to two adjacent blades (hereinafter referred to as "blade A" and "blade B") among the plurality of blades 2 of the wind power generation device 1. Further, FIG. 4(a) shows the case where neither blade A nor blade B is damaged, and FIG. 4(b) shows the case where only blade B is damaged.

[0046] At time t1, radio waves that do not pass through blade A and blade B are received. Therefore, the measured amplitude A0 is large.

[0047] At time t2, radio waves that have passed through blade A are received. Therefore, a relatively small amplitude A1 is measured compared to time t1. For the sake of simplicity of explanation, normalization (step S4 in FIG. 3) is not considered here (the same applies hereinafter).

[0048] At time t3, radio waves that have passed through blade B are received. Here, when blade B is not damaged (FIG. 4(a)), an amplitude A2 of the same degree as time t2 is measured. On the other hand, when blade B is damaged (FIG. 4(b)), an amplitude A2' that is smaller than time t1 but larger than time t2 is measured. For example, when a part of blade B is missing, or when a part is carbonized due to lightning strike or the lightning protection wire is melted, the amplitude A2' changes compared to the amplitude A2.

[0049] Therefore, the determination unit 225 compares the amplitude A1 and the amplitude A2 (A2') to detect damage to blade A and / or blade B. As a specific example, the determination unit 225 determines that there is damage if the difference between the two exceeds a predetermined threshold value, and determines that there is no damage if it is below the threshold value. In the case of FIG. 4(a), since the amplitude A1 and the amplitude A2 are of the same degree and the difference between the two is small, it is determined that there is no damage. In the case of FIG. 4(b), since the difference between the amplitude A1 and the amplitude A2' is large, it is determined that there is damage.

[0050] In this processing example, the determination unit 225 compares the amplitude of the radio wave that has passed through blade A with the amplitude of the radio wave that has passed through blade B. However, the amplitude of the radio wave that has passed through blade A at a certain time may be compared with the amplitude of the radio wave that has passed through blade A at another time (for example, one rotation before if the rotation speed of blade A is several tens of rotations per minute) to detect damage to blade A.

[0051] In this way, the determination unit 225 can detect damage (such as lightning strikes and bird strikes) that occurs in a short period.

[0052] On the other hand, blade 2 may be damaged over a long period of several days to several years (such as the crack progressing over time). Therefore, the determination unit 225 may compare the amplitude of the radio wave that has passed through blade A at a certain time with the amplitude of the radio wave that has passed through blade A at a time after a predetermined period (several days to several years) has elapsed to detect damage to blade A. Also, the determination unit 225 may perform trend analysis of the amplitude over a predetermined period and detect damage based on the result. This enables prevention (prediction) and maintenance of blade 2.

[0053] Although an example of detecting damage based on amplitude has been shown above, similarly, damage can also be detected based on phase or polarization plane.

[0054] According to the first embodiment in this way, damage to blade 2 in the wind power generation device 1 can be detected. When detecting damage by visual inspection or image analysis using camera shooting, it is necessary to stop blade 2, but according to this embodiment, blade 2 can be rotated without being stopped. Also, it is safer compared to detecting damage by high-altitude work by workers.

[0055] (Second Embodiment) In the above-described first embodiment, the GNSS satellite 11 was used as the radio wave transmission source 10 in FIG. 1. In contrast, in the second embodiment described below, a radio wave transmission device is provided as the radio wave transmission source 10. Hereinafter, the points common to the first embodiment will be omitted or simplified in the description, and the description will focus on the different points.

[0056] Figure 5 is a schematic block diagram of the blade inspection system 20' according to the second embodiment. This blade inspection system 20' includes a radio wave transmitter 12, a receiver 21, and a detector 22.

[0057] The radio wave transmitter 12 transmits radio waves to the receiver 21. It is desirable that the radio wave transmitter 12 be mounted on a drone (not shown). This is because by controlling the position of the drone, radio waves can be transmitted from a desired position and transmitted through a desired position on the blade 2, and also because by moving the drone, the position where the radio waves penetrate the blade 2 can be scanned. That is, in the first embodiment, the baseline is determined by the position of the GNSS satellite 11, whereas in this embodiment, by mounting the radio wave transmitter 12 on the drone, the baseline can be arbitrarily set.

[0058] The radio waves transmitted by the radio wave transmitter 12 correspond to the radio waves from the GNSS satellite 11 in the first embodiment and can also be called pseudo-GNSS radio waves. Here, although the flight position of the drone is measured by the GNSS satellite 11, it is desirable that the radio wave transmitter 12 transmit radio waves with a frequency different from that of the radio waves from the GNSS satellite 11 so as not to interfere with the positioning. Characteristics other than the frequency may be the same as those of the radio waves from the GNSS satellite 11.

[0059] The radio wave transmitter 12 includes a signal generation unit 121, a power amplifier 122, an antenna 123, and a control device 124.

[0060] The signal generation unit 121 generates an electrical signal in response to control from the control device 124. This electrical signal is preferably modulated by a modulation method (e.g., multi-value PSK modulation) that makes it easy to measure the phase in the detector 22. The power amplifier 122 amplifies the generated electrical signal.

[0061] Antenna 123 converts an electrical signal into a radio wave and transmits it. Antenna 123 may include an antenna 1231 that transmits a horizontally polarized radio wave and an antenna 1232 that transmits a vertically polarized radio wave. In this case, the radio wave transmitting device 12 has an antenna switching device 1233 that switches which of the antennas 1231 and 1232 to transmit a radio wave in accordance with control from the control device 124.

[0062] The receiving unit 21 and the detecting unit 22 may be the same as those in the first embodiment. Note that the receiving unit 21 may be mounted on another drone. Alternatively, the receiving unit 21 may be installed in the nacelle 3 (see FIG. 1), the tower section of the wind power generation device 1, or on the ground. However, since the blade 2 changes its orientation depending on the wind direction, it is desirable to install it on the nacelle 3 that moves in synchronization with the blade 2.

[0063] As described above, it is also possible to detect damage to the blade 2 by using the radio wave transmitting device 12 instead of the GNSS satellite 11.

[0064] Any part or all of each functional unit described in this specification may be realized by a program. The program mentioned in this specification may be non-temporarily recorded on a computer-readable recording medium and distributed, or may be distributed via a communication line (including wireless communication) such as the Internet, or may be distributed in a state installed on an arbitrary terminal.

[0065] Based on the above description, those skilled in the art may be able to conceive of additional effects and various modifications of the present invention, but the aspects of the present invention are not limited to the individual embodiments described above. For example, inventions that take out only a part of each embodiment or inventions that combine a plurality of embodiments are naturally assumed. Various additions, changes, and partial deletions are possible without departing from the conceptual ideas and spirits of the present invention derived from the content defined in the claims and their equivalents.

[0066] For example, what is described as one device (or component, the same hereinafter) in this specification (including what is depicted as one device in the drawings) may be implemented by a plurality of devices. Conversely, what is described as a plurality of devices in this specification (including what is depicted as a plurality of devices in the drawings) may be implemented by one device. Alternatively, part or all of the means and functions assumed to be included in a certain device (for example, a server) may be included in another device (for example, a user terminal). Also, a "system" may be composed of one device or may be composed of two or more devices (for example, a server and a user terminal, or a plurality of user terminals).

[0067] Also, not all of the matters described in this specification are essential requirements. In particular, matters described in this specification but not described in the claims can be regarded as optional additional matters.

[0068] In addition, unless otherwise specified, the term "means" in this specification and the claims means hardware (or functions realized by hardware) itself and does not include humans (or human mental activities).

[0069] It should also be noted that the applicant only knows the publicly known inventions described in the documents in the "Prior Art Documents" column of this specification, and the present invention is not necessarily intended to solve the problems in the publicly known inventions in the same documents. The problems to be solved by the present invention should be determined in consideration of the entire specification. For example, in this specification, if there is a description that a predetermined effect is achieved by a specific configuration, it can also be said that the problem that is the reverse of the predetermined effect is solved. However, it is not necessarily the intention that such a specific configuration is an essential requirement.

Explanation of Reference Signs

[0070] 1 Wind power generation device 2 Blade 3 Nacelle 10 Radio wave transmitter 11 GNSS satellites 12 Radio wave transmission device 121 Signal generation unit 122 Power amplifier 123, 1231, 1232 Antenna 1233 Antenna switching device 124 Control device 20 Blade inspection system 21 Detection unit 211, 2111, 2112 Antenna 212 Front end 213 Correlation processing unit 214 Antenna switching device 22 Detection unit 221 Amplitude measurement unit 222 Phase measurement unit 223 Polarization plane measurement unit 224 Memory unit 225 Judgment unit

Claims

1. A receiving unit that receives radio waves from a GNSS satellite that have passed through the blades of the wind power generation device; A blade inspection system comprising: a detection unit that detects damage to the blade based on the specifications of the received radio waves.

2. The blade inspection system according to claim 1 , wherein the parameters of the radio waves are an amplitude, a phase, or a polarization plane of the received radio waves.

3. A radio wave transmitting device for transmitting radio waves; a receiving section for receiving radio waves from the radio wave transmitting device that have passed through the blades of a wind turbine; A detection unit that detects damage to the blade based on the parameters of the received radio waves, A blade inspection system, wherein the parameter is an amplitude.

4. A radio wave transmitting device for transmitting radio waves; a receiving section for receiving radio waves from the radio wave transmitting device that have passed through the blades of a wind turbine; A detection unit that detects damage to the blade based on the parameters of the received radio waves, A blade inspection system, wherein the parameter is phase.

5. A radio wave transmitting device for transmitting radio waves; a receiving section for receiving radio waves from the radio wave transmitting device that have passed through the blades of a wind turbine; A detection unit that detects damage to the blade based on the parameters of the received radio waves, A blade inspection system, wherein the parameter is a polarization plane.

6. The blade inspection system according to claim 3 , wherein the radio wave transmitting device is mounted on a drone.

7. The blade inspection system according to claim 3 , wherein the frequency of the radio waves is different from the frequency of a GNSS satellite.

8. The receiving unit receives radio waves that have passed through the blade and radio waves that have not passed through the blade, 6. The blade inspection system according to claim 1, wherein the detection unit normalizes parameters of radio waves that have passed through the blade with parameters of radio waves that have not passed through the blade, and detects damage to the blade based on the normalized parameters.

9. The wind turbine generator is provided with a first blade and a second blade as the blades, A blade inspection system as described in any one of claims 1 to 5, wherein the detection unit detects damage to the first blade and / or the second blade by comparing parameters of the radio waves that have passed through the first blade with parameters of the radio waves that have passed through the second blade.

10. 6. The blade inspection system according to claim 1, wherein the detection unit detects damage to the blade by comparing parameters of radio waves transmitted through the blade at a certain time with parameters of radio waves transmitted through the blade at another time.

11. A first step of receiving radio waves from a GNSS satellite that have passed through a blade of a wind turbine; and a second step of detecting damage to the blade based on the parameters of the received radio waves.

12. A first step of receiving radio waves from a radio wave transmitting device that have passed through a blade of a wind turbine generator; and a second step of detecting damage to the blade based on the amplitude of the received radio waves.

13. A first step of receiving radio waves from a radio wave transmitting device that have passed through a blade of a wind turbine generator; and a second step of detecting damage to the blade based on the phase of the received radio waves.

14. A first step of receiving radio waves from a radio wave transmitting device that have passed through a blade of a wind turbine generator; and a second step of detecting damage to the blade based on the axial ratio of the received radio waves.

15. 15. The blade inspection method according to claim 11, wherein in the first step, radio waves that have passed through a rotating blade are received.

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