JP2013148022A - Wind power generation device and operation control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wind power generation device and an operation control method thereof, capable of monitoring a damage state of a conductive composite material, while reducing failure risk of a damage detecting system by a lightning current.SOLUTION: A wind power generation device includes a wind turbine blade 1 at least a part of which is constituted of conductive composite materials 12, a plurality of measuring electrodes 20installed in the conductive composite materials 12, and a resistance measuring instrument 24 connected to the respective measuring electrodes 20via first switches 22. When operating the wind power generation device by an ordinary operation mode, the first switches 22are opened, and the resistance measuring instrument 24 is separated from the measuring electrodes 20. When an operation mode of the wind power generation device is switched to a damage detecting mode from the ordinary operation mode, first switches 22and 22are closed, the resistance measuring instrument 24 is electrically connected with a pair of electrodes 20and 20, and electric resistance between the pair of electrodes 20and 20is measured by the resistance measuring instrument 24 in this state. Damage of the conductive composite material 12 is detected based on a measuring result of the resistance measuring instrument 24.

Description

  The present invention relates to a wind turbine generator and an operation control method thereof, and more particularly, to a wind turbine generator having wind turbine blades at least partially made of a conductive composite material and an operation control method thereof.

  In recent years, wind power generators that generate power using wind as a renewable energy have been widely used from the viewpoint of conservation of the global environment.

  Conventionally, wind turbine blades are usually made of GFRP (Glass Fiber Reinforced Plastic). However, as wind turbine generators become larger, it is necessary to reduce the weight and deflection of wind turbine blades. In many cases, CFRP (Carbon Fiber Reinforced Plastic), which is more excellent in specific strength and rigidity than GFRP, is adopted as a main structural member of a wind turbine blade.

  However, since the CFRP of a windmill blade has a risk of causing strength reduction due to damage caused by lightning strikes or delamination due to collision of flying objects, it is important to periodically grasp the damage state of the CFRP. Visual inspection is the simplest way to grasp the damage state of CFRP, but it is difficult to find delamination inside the CFRP by visual inspection. Therefore, development of a damage detection method that can grasp the damage state of CFRP including delamination inside the CFRP is desired.

As a general CFRP damage detection method, Patent Document 1 measures the electrical resistance between electrodes provided on a conductive composite material, and detects the position and size of the composite material peeling from the measurement result. A method is disclosed. As described above, the method of detecting the damage of the CFRP by the change of the electrical resistance of the CFRP is referred to as an electrical resistance change method.
Non-Patent Document 1 discloses a method of detecting CFRP damage from the rate of change in electrical resistance caused by the temperature rise of CFRP by heating CFRP with Joule heat. This method detects the damage of CFRP by using the rate of change of electric resistance due to the temperature change of CFRP in order to avoid the problem of the electric resistance change method that the defect of the electrode may affect the accuracy of damage detection of CFRP. It is.

JP 2001-318070 A

Takahashi, K. and two others, “Detection of delamination of CFRP structure using electrical resistance change due to Joule heating”, Transactions of the Japan Society of Mechanical Engineers, December 2008, Vol. 74, No. 748, p. 81-88

The size of wind power generators has been increased from the viewpoint of improving power generation efficiency, and huge wind power generators having a rotor diameter of more than a few tens of meters are being put into practical use. Therefore, the tip of the wind turbine blade passes through a position (high place) far away from the ground surface when the rotor rotates, and the wind turbine blade is likely to be a target of lightning strike. And CFRP which has electroconductivity can become a path | route of the lightning strike current in a windmill blade.
Therefore, when a general CFRP damage detection method described in Patent Document 1 or Non-Patent Document 1 is applied to a wind turbine blade equipped with CFRP, a lightning strike is applied to a damage detection system such as a resistance measuring instrument via an electrode provided on the CFRP. Current can flow and damage detection systems can fail.

  The present invention has been made in view of the above circumstances, and a wind turbine generator capable of monitoring a damaged state of a conductive composite material such as CFRP while reducing the failure risk of a damage detection system caused by a lightning strike current, and its An object is to provide an operation control method.

An operation control method for a wind turbine generator according to the present invention includes a wind turbine blade at least partly composed of a conductive composite material, a plurality of measurement electrodes attached to the conductive composite material, and each measurement electrode. In the operation control method of a wind turbine generator having a resistance measuring instrument connected via a first switch, the first measuring instrument is opened and the resistance measuring instrument is disconnected from the measurement electrode. A step of operating the wind turbine generator in a normal operation mode; and when the operation mode of the wind turbine generator is switched from the normal operation mode to a damage detection mode, the first switch is closed and the resistance measuring instrument is Conducting a pair of electrodes among the measurement electrodes, and measuring the resistance between the pair of electrodes in a state where the first switch is closed and the resistance measuring instrument is connected to the pair of electrodes. A step of measuring by, based on the measurement values of the electrical resistance, characterized in that it comprises the steps of detecting damage to the electrically conductive composite.
The conductive composite material constituting at least a part of the wind turbine blade may be a fiber reinforced plastic obtained by reinforcing a resin matrix with conductive fibers, and may be a carbon fiber reinforced plastic, for example.

  According to the wind turbine generator operation control method, when the damage detection mode is selected, the first switch is closed and the resistance measuring instrument is connected to the pair of electrodes to measure the electrical resistance between the pair of electrodes. Therefore, the damage of the conductive composite material can be grasped by the electric resistance change method. On the other hand, when the normal operation mode is selected, the first switch is opened and the resistance measuring device is disconnected from the measurement electrode, so that the risk of failure of the resistance measuring device (damage detection system) due to the lightning current can be reduced.

In the wind power generator operation control method, the wind power generator includes a pair of heating electrodes attached to the conductive composite material, and a voltage applicator connected to the heating electrodes via a second switch. And when the damage detection mode is selected as the operation mode of the wind turbine generator, the second switch is closed and the voltage applicator is conducted to the heating electrode, and the conductive composite material In the normal operation mode, the second switch is opened to keep the voltage applicator disconnected from the heating electrode.
In this way, when the normal operation mode is selected, the second switch is opened and the voltage applicator is disconnected from the heating electrode, so that the rate of change in electrical resistance due to the temperature change of the conductive composite material is used as in Non-Patent Document 2. Thus, when performing damage detection, the risk of failure of the voltage applicator can be reduced.

In the wind turbine generator operation control method, the conductive composite material extends in the blade length direction of the wind turbine blade, and three or more measurement electrodes are attached to different blade length direction positions, In the step of measuring resistance, the electrical resistance is measured for each of the pair of electrodes in a plurality of sets, and in the step of detecting damage, the damaged portion of the conductive composite material is determined based on the electrical resistance of each set. You may specify.
Thereby, the damaged part of the electroconductive composite material extended in a blade length direction can be known, and a windmill blade can be maintained efficiently.

The operation control method of the wind power generator includes a step of entering light into an optical fiber embedded in the conductive composite material, and a step of detecting scattered light or transmitted light of the light incident on the optical fiber; In the step of detecting the damage, the damage of the conductive composite material may be detected based on the measured value of the electrical resistance and the scattered light or transmitted light.
Thus, by considering not only the electrical resistance between the measurement electrodes attached to the conductive composite material, but also the scattered light or transmitted light of the light incident on the optical fiber embedded in the conductive composite material, Damage to the conductive composite can be detected with higher accuracy.

  As a specific method of using the optical fiber embedded in the conductive composite material for detecting damage to the conductive composite material, for example, the distortion amount of the optical fiber is calculated from the frequency shift of the Brillouin scattered light of the light incident on the optical fiber. Then, the amount of distortion may be compared with a predetermined threshold value to determine whether or not the conductive composite material is damaged.

  When an optical fiber embedded in a conductive composite material is used for detecting damage to the conductive composite material, the damaged portion of the conductive composite material may be specified based on the scattered light. For example, from the time until the Brillouin scattered light whose frequency is shifted in the strain generation portion of the optical fiber returns to the measuring instrument (BOTDR type measuring instrument), the strain generating position of the optical fiber (that is, the damaged portion of the conductive composite material) is determined. You may specify.

  In the wind power generator operation control method, when damage to the conductive composite material is detected, at least one of stopping the wind power generator and outputting an alarm may be performed.

  Further, the wind power generator according to the present invention is a wind power generator provided with a wind turbine blade at least partially composed of a conductive composite material, and a plurality of measurement electrodes attached to the conductive composite material, A resistance measuring instrument connected to the measuring electrode via a first switch; a first switching control section for controlling the opening and closing of the first switch; a measuring instrument control section for controlling the resistance measuring instrument; Based on the measurement result of the resistance measuring instrument, a damage detection unit that detects damage of the conductive composite material, and an operation mode that selects one of a normal operation mode and a damage detection mode as the operation mode of the wind turbine generator And when the normal operation mode is selected by the operation mode selection unit, the first opening / closing control unit maintains the state in which the resistance measuring instrument is disconnected from the measurement electrode. 1 When the closure is opened and the damage detection mode is selected by the operation mode selection unit, the first opening / closing control unit is configured to cause the resistance measuring instrument to conduct to a pair of electrodes among the measurement electrodes. 1 The switch is closed, the measuring instrument control unit acquires the electrical resistance between the pair of electrodes by the resistance measuring instrument, and the damage detecting unit It is characterized by detecting damage.

  According to this wind turbine generator, when the damage detection mode is selected, the first switch is closed by the first opening / closing controller, and the resistance measuring instrument is connected to the pair of electrodes to measure the electrical resistance between the pair of electrodes. Therefore, the damaged state of the conductive composite material can be grasped by the electric resistance change method. On the other hand, when the normal operation mode is selected, the first switch is opened by the first switching control unit so that the resistance measuring instrument is disconnected from the measuring electrode, so the risk of failure of the resistance measuring instrument (damage detection system) due to lightning current is reduced. Can be reduced.

In the wind turbine generator described above, the wind turbine blades are respectively provided on the belly side surface and the back side surface of the wind turbine blade, and connect the spar caps extending in the blade length direction and the spar caps on the belly side surface and the back side surface. The conductive composite material may be the spar cap, and the measurement electrode may be disposed in a region of the inner surface of the spar cap excluding the junction with the spar.
As a result, it is possible to prevent the windmill blade strength and manufacturability from being lowered due to the attachment of the measurement electrode, and to avoid the measurement electrode from being affected by the lightning strike current.

  According to the present invention, when the damage detection mode is selected, the first switch is closed and the resistance measuring instrument is connected to the pair of electrodes to measure the electrical resistance between the pair of electrodes. Can grasp the damaged state of the conductive composite material. On the other hand, when the normal operation mode is selected, the first switch is opened and the resistance measuring instrument is disconnected from the measurement electrode, so that the risk of failure of the resistance measuring instrument due to the lightning current can be reduced.

It is a figure which shows the structural example of a windmill blade. It is AA sectional drawing of FIG. It is a figure which shows the structural example of the damage detection system of the windmill blade which concerns on 1st Embodiment. It is a figure which shows the example of the attachment position of the electrode for a measurement, (a) is sectional drawing of a windmill blade (sectional drawing in the blade length direction position different from FIG. 2), (b) is the B section in FIG. 4 (a). It is an enlarged view of the area | region shown by. It is a figure which shows the structural example of the damage detection system and windmill controller in 1st Embodiment. It is a graph showing the time course of the rate of change in resistance [Delta] R c _/ R ₁ in the natural cooling of the finished heating CFRP. It is a flowchart which shows the operation control method of the wind power generator which concerns on 1st Embodiment. It is a figure which shows the structural example of the damage detection system of the windmill blade in 2nd Embodiment. It is a figure which shows the structural example of the damage detection system in 2nd Embodiment, and a windmill controller. It is a figure which shows the structural example of the optical fiber measuring device which used the BOTDR type measuring device and the Bragg grating sensor together. It is a graph which shows an example of distortion dependence of Brillouin frequency shift and Bragg reflection wavelength shift. It is a graph which shows an example of the temperature dependence of Brillouin frequency shift and Bragg reflection wavelength shift.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration example of a wind turbine blade. 2 is a cross-sectional view taken along the line AA in FIG.
As shown in FIG. 1, the wind turbine blade 1 extends in the blade length direction from the blade root portion 2 connected to the hub of the wind turbine generator to the tip portion 4. As shown in FIG. 2, the wind turbine blade 1 includes an outer skin (shell) 10 having an inner layer 10a and an outer layer 10b, and a spar cap 12 provided on the inner layer 10a of the outer skin 10 so as to extend in the blade length direction. And a spar (shear web) 14 provided between the dorsal and ventral spar caps 12.

The outer skin 10 is formed of an insulator such as GFRP or balsa material. On the other hand, the spar cap 12 which is a strength member is formed of CFRP (conductive composite material). Therefore, each spar cap 12 is covered with a CFRP protective conductor (composite protective conductor) 16 from the viewpoint of preventing direct lightning strike on the CFRP spar cap 12.
Note that one end of the CFRP protective conductor 16 is electrically connected to the receptor 6 via a base plate 8 provided inside the distal end portion 4. The other end of the CFRP protective conductor 16 is electrically connected to the ground wire in the hub via a conductive member (not shown) at the blade root portion 2. That is, the CFRP protective conductor 16 has a function as a down conductor that guides the lightning current captured by the receptor 6 to the blade root 2 in addition to preventing lightning directly to the spar cap 12. In such a lightning protection design, almost all lightning strikes are captured by the receptor 6, and the remaining lightning strikes are captured by the CFRP protective conductor 16 around the tip 4, so that the CFRP 12 is not directly subjected to lightning strikes. Then, the lightning current captured by the CFRP protective conductor 16 around the receptor 6 or the tip 4 is guided to the blade root 2 by the CFRP protective conductor 16.
In addition, the CFRP protective conductor 16 and the spar cap 12 are connected to each other by the conductor 18 at a plurality of locations in the blade length direction to be equipotential. Note that the spar 14 may be made of CFRP in order to make the dorsal spar cap 12 and the ventral spar cap 12 equipotential.

FIG. 3 is a diagram illustrating a configuration example of a wind turbine blade damage detection system. In the damage detection system 100 shown in the figure, a plurality of measurement electrodes 20 _i (i = 1, 2,... M, where m is an integer of 2 or more) are attached to a CFRP (spar cap) 12 and these measurements are performed. A resistance measuring instrument 24 is connected to each of the electrodes 20 _i via a corresponding first switch 22 _i . Further, heating electrodes 26A and 26B are attached to both ends of the CFRP 12, and a voltage applicator 29 may be connected to the heating electrodes 26A and 26B via second switches 28A and 28B. .
In addition, each part (1st switch 22 _i , 2nd switch 28A, 28B, the resistance measuring device 24, and the voltage applicator 29) of the damage detection system 100 operate | moves under control of the windmill controller 30. FIG. Details of the windmill controller 30 will be described later.

FIG. 4 is a view showing an example of the attachment position of the measurement electrode 20 _i , and FIG. 4A is a cross-sectional view of the wind turbine blade 1 (a cross-sectional view at a blade length direction position different from FIG. 2), FIG. ) Is an enlarged view of a region indicated by a portion B in FIG.
If the measurement electrode 20 _i is attached to the outer surface 12 B of the CFRP 12 (see FIG. 4B), it is not only susceptible to lightning current, but also causes wrinkles of the outer skin 10. Further, since the side surface 12C of CFRP12 is a boundary between the inner layer 10a of the outer skin 10 made of GFRP and balsa wood, etc., mounting the side 12C of CFRP12 view of the production of the wind turbine blade 1 measurement electrodes 20 _i Undesirable location. Furthermore, the joint 13 between spar 14 of the inner surface 12A of the CFRP12, since an important point for ensuring the strength of the wind turbine blade 1 can not be said to be desirable as a mounting position of the measurement electrode 20 _i.
Therefore, as shown in FIGS. 4A and 4B, the measurement electrode 20 _i is preferably attached to a region of the inner surface 12 </ b> A of the CFRP (spar cap) 12 excluding the joint portion 13 with the spar 14. . As a result, the strength and manufacturability of the wind turbine blade 1 due to the attachment of the measurement electrode 20 _i can be prevented, and the measurement electrode 20 _i can be prevented from being affected by the lightning current.
Note that the heating electrodes 26A and 26B are also preferably attached to a region of the inner surface 12A of the CFRP (spar cap) 12 excluding the joint portion 13 with the spar 14 like the measurement electrode 20 _i .

FIG. 5 is a diagram illustrating a configuration example of the damage detection system 100 and the windmill controller 30. As shown in the figure, the windmill controller 30 includes an operation mode selection unit 38 that selects an operation mode of the wind turbine generator, a first opening / closing control unit 31 that controls opening / closing of the first switch 22 _i , and a resistance measuring device 24. A controller 32 for controlling the switching, a second switching controller 33 for controlling the opening / closing of the second switches 28A and 28B, a voltage applying controller 34 for controlling the voltage applicator 29, and the presence or absence of damage to the CFRP 12 And a damage detection unit 36.

  The operation mode selection unit 38 selects either the normal operation mode or the damage detection mode as the operation mode of the wind turbine generator. Here, the normal operation mode is an operation mode only for power generation without detecting damage of the CFRP 12, and generates power when the wind speed is equal to or higher than the cut-in wind speed, and waits when the wind speed is lower than the cut-in wind speed. It is an operation mode to do. In contrast, the damage detection mode is an operation mode in which damage detection of the CFRP 12 is performed. Note that when the damage detection mode is selected, the wind turbine generator may generate power or may stand by without generating power.

  The operation mode selection unit 38 may switch from the normal operation mode to the damage detection mode during periodic inspections, in bad weather such as thunderstorms and typhoons, or when a lightning strike to the wind turbine blade 1 is detected by the lightning strike monitoring device. . The operation mode switching by the operation mode selection unit 38 is performed automatically or manually. For example, the operation mode selection unit 38 may automatically switch the operation mode in accordance with a command from the wind farm control room. Alternatively, the maintenance person manually operates the control panel in the wind turbine generator or remotely operates from a remote place via wireless or wired, and performs switching of the operation mode by the operation mode selection unit 38. Also good.

The first opening / closing controller 31 selects all the first switches 22 _i (i = 1, 2,... M) so as to maintain the state where the resistance measuring device 24 is disconnected from the measuring electrode 20 _i when the normal operation mode is selected. However, m is an integer of 2 or more.) As a result, it is possible to prevent the lightning current from flowing into the resistance measuring instrument 24 due to lightning strike on the wind turbine blade 1 during the normal operation mode selection.
Similarly, the second switch control unit 33 opens the second switches 28A and 28B so as to maintain the state where the voltage applicator 29 is disconnected from the heating electrodes 26A and 26B when the normal mode is selected. Thereby, it is possible to prevent the lightning current from flowing into the voltage applicator 29 due to the lightning strike on the wind turbine blade 1 during the normal operation mode selection.

On the other hand, when the damage detection mode is selected, the first switching control unit 31 closes the pair of first switches 22 _k and 22 _l and causes the corresponding electrodes 20 _k and 20 _l to conduct to the resistance measuring device 24. . In this state, the resistance measuring instrument 24 measures the electrical resistance between the pair of electrodes 20 _k and 20 _l under the control of the measuring instrument control unit 31. The damage detector 36, resistor measuring 24 the electrical resistance between the electrodes ₂₀ k, 20 _l as measured by, by comparing the electrical resistance between the electrodes ₂₀ k before CFRP injury is known, 20 _l, Whether the CFRP 12 is damaged between the electrodes 20 _k and 20 _l is determined.

Meanwhile, the electrical resistance between the electrodes ₂₀ k, 20 _l also depends on the defect state of the measurement electrodes ₂₀ k, 20 _l. Therefore, in order to avoid deterioration of the damage detection accuracy of the CFRP 12 due to the loss of the measurement electrodes 20 _k , 20 _l , the damage of the CFRP 12 is detected using the change rate of the electrical resistance between the electrodes 20 _k , 20 _l due to the temperature change of the CFRP 12. May be. At this time, in order to apply a temperature change to the CFRP 12, the CFRP 12 may be heated with Joule heat using the voltage applicator 29. That is, when the damage detection mode is selected by the operation mode selection unit 38, the second switching controller 33 closes the second switches 28A and 28B and causes the voltage applicator 29 to conduct to the heating electrodes 26A and 26B. The voltage applicator 29 may apply a voltage to the CFRP 12 under the control of the voltage application control unit 34.
The damage detection of the CFRP 12 may be performed based on the resistance change rate when the temperature of the CFRP 12 is increased, or may be performed based on the resistance change rate when the temperature of the CFRP 12 is decreased. For example, when the electric resistance of the electrodes 20 _k and 20 _l at the start of heating of the CFRP 12 is R ₀ and the change in electric resistance ΔR _h during the heating of the CFRP 12, the behavior of the CFRP 12 is determined from the behavior of the resistance change rate ΔR _h / R _0. Damage may be detected. Alternatively, when the electric resistance of the electrodes 20 _k and 20 _l at the end of heating of the CFRP 12 is R ₁ and the change in electric resistance ΔR _c during natural cooling after the heating of the CFRP 12 is finished, the resistance change rate ΔR _c / R ₁ The damage of the CFRP 12 may be detected from the above behavior.

FIG. 6 is a graph showing the change over time of the rate of change in resistance ΔR _c / R ₁ during natural cooling after the heating of the CFRP 12.
As shown in the figure, regardless of whether the CFRP 12 is damaged or not, in any case, the electrical resistance recovers and increases as the temperature of the CFRP 12 during natural cooling decreases. The amount of increase in resistance is smaller when the CFRP 12 is damaged than when the CFRP 12 is not damaged. On the other hand, it has been found that the loss of the electrodes 20 _k and 20 _l hardly affects the resistance change rate ΔR _c / R ₁ . Therefore, the damage of the CFRP 12 can be detected with high accuracy from the behavior of the resistance change rate ΔR _c / R ₁ .

Further, when the damage detection mode is selected, the electrical resistance between a plurality of sets of electrodes may be measured by the resistance measuring device 24, and the damaged portion of the CFRP 12 may be specified based on the electrical resistance of each set. For example, a plurality of measurement electrodes 20 _i (i = 1, 2,... M, where m is an integer of 3 or more) are provided in the blade length direction, and a plurality of sets of adjacent electrodes 20 _j−1 , 20 are provided. electrical resistance _{R j (j = 2, ...} m.) between _j from may identify damaged portion of the CFRP 12.

  Next, an operation control method for the wind turbine generator of this embodiment will be described. FIG. 7 is a flowchart showing an operation control method for the wind turbine generator of this embodiment.

First, in step S2, either one of the normal operation mode and the damage detection mode is selected as the operation mode of the wind turbine generator by the operation mode selection unit 38. For example, when a lightning strike on the wind turbine blade 1 is detected by a thunderstorm or a typhoon, or when a lightning strike is detected by the lightning strike monitoring device, the normal operation mode is switched to the damage detection mode to detect the damage of the CFRP 12. Also good.
When the normal operation mode as the operation mode of the wind turbine generator has been selected (NO determination at step S4), and for measuring the resistance measuring instrument 24 first closing controller 31 opens all of the first switch 22 _i with disconnected from the electrode 20 _i (step S6), and the second on-off controller 33 is disconnected from the second switch 28A, the voltage applicator 29 open 28B heating electrode 26A, 26B (step S8), and the wind in this condition Operate the generator. Then, it returns to step S2 and selects the operation mode of a wind power generator again.
On the other hand, when the damage detection mode is selected as the operation mode of the wind turbine generator (YES determination in step S4), the second switching controller 33 closes the second switches 28A and 28B in step S10 and turns on the voltage applicator 29. Conduction is conducted to the heating electrodes 26A and 26B. Then, under the control of the voltage application control unit 34, the voltage applicator 29 applies a voltage to the CFRP 12 and heats the CFRP 12 by Joule heat. And it progresses to step S14 and a pair of electrode _20j-1 and _20j is resistance measuring instrument 24 among measurement electrodes _20i (i = 1, 2, ... m. However, m is an integer greater than or equal to 3). The first switches 22 _j-1 and 22 _j are closed by the first opening / closing control unit 31 so as to be electrically connected to each other. In this state, the resistance measuring instrument 24 measures the electrical resistance R _j between the electrodes 20 _j-1 and 20 _j during the temperature change of the CFRP 12 (step S16). At step S18, whether the electric resistance R _j are measured for the combination of all of the electrodes 20 _j-1, 20 j of the measurement schedule is determined, if the measurement of all the electrode sets of the measurement will not complete (NO determination at step S18), the electrodes to be measured are changed, and steps S10 to S16 are repeated. When the measurement for all electrode sets scheduled to be measured is completed (YES in step S18), the damage detection unit 36 determines the CFRP 12 based on the rate of change of the electrical resistance R _j due to the temperature change of the CFRP 12 acquired from the resistance measuring device 24. Damage detection and identification of the damaged part are performed (step S20). When it is determined that the CFRP 12 is damaged (YES determination in step S22), the process proceeds to step S24, and at least one of the stop of the wind power generator and the alarm output is performed. On the other hand, when it is determined that the CFRP 12 is not damaged (NO determination in step S22), the process returns to step S2 and the operation mode of the wind turbine generator is selected again.

According to the present embodiment, when the damage detection mode is selected, the first opening / closing control unit 31 closes the first switches 22 _k and 22 _l to cause the resistance measuring device 24 to conduct to the pair of electrodes 22 _k and 22 _l. Since the electrical resistance between the pair of electrodes 22 _k and 22 _l is measured, the damaged state of the CFRP 12 can be grasped by the electrical resistance change method. On the other hand, when the normal operation mode is selected, all the first switches 22 _i are opened by the first opening / closing control unit 31 so as to disconnect the resistance measuring devices 24 from the measuring electrodes 20 _i , so that the resistance measuring device 24 based on a lightning current is used. The risk of failure can be reduced.

  Further, according to the present embodiment, when the normal operation mode is selected, the second switches 28A and 28B are opened and the voltage applicator 29 is disconnected from the heating electrodes 26A and 26B, whereby the rate of change ΔR in electrical resistance due to the temperature change of the CFRP 12 is achieved. When performing damage detection using / R, the failure risk of the voltage applicator 29 can be reduced.

Further, three or more measurement electrodes 20 _i (i = 1, 2,... M, where m is an integer of 3 or more) are attached to different blade length direction positions, and a plurality of sets of electrodes 20 _j−1 , 20 are attached. _{Since the} electrical resistance R _j is measured for each of _j and used to identify the damaged portion of the CFRP 12, the damaged portion of the CFRP 12 extending in the blade length direction can be known, and the maintenance of the wind turbine blade 1 can be performed efficiently. It can be carried out.

Furthermore, the strength and manufacturability of the wind turbine blade 1 can be obtained by attaching the measurement electrode 20 _i and the heating electrodes 26 A and 26 B to the region of the inner surface 12 A of the CFRP (spar cap) 12 excluding the joint portion 13 with the spar 14. Can be prevented, and the influence of the lightning strike current on the electrode can be avoided.

[Second Embodiment]
Next, a wind turbine generator according to a second embodiment will be described. The wind power generator according to the present embodiment is the same as the wind power generator according to the first embodiment, except that a health monitoring function using an optical fiber embedded in the CFRP 12 is additionally provided in the damage detection system. . Therefore, here, the same parts as those in the first embodiment are denoted by the same reference numerals, the description thereof is omitted, and the description will be focused on differences from the first embodiment.

  FIG. 8 is a diagram illustrating a configuration example of a damage detection system according to the present embodiment. FIG. 9 is a diagram illustrating a configuration example of the damage detection system and the wind turbine controller according to the present embodiment.

  The damage detection system 110 shown in FIG. 9 is obtained by adding an optical fiber 44 embedded in the CFRP 12 and an optical fiber measuring device 46 connected thereto to the damage detection system 100 (see FIG. 3) in the first embodiment. is there.

The optical fiber 44 is provided over substantially the entire length of the CFRP 12 along the blade length direction. The optical fiber measuring device 46 enters the optical fiber 44 and detects the scattered light. For example, the optical fiber measuring device 46 may be an OTDR system that detects the bending of the optical fiber 44 from a decrease in the backscattered light of the light incident on the optical fiber 44, or the optical fiber measuring device 46 A BOTDR system that detects distortion of the optical fiber 44 from the frequency shift of Brillouin scattered light may be used. As shown in FIG. 9, the measurement result of the optical fiber measurement device 46 is sent to the damage detection unit 36 of the windmill controller 30 and is used for the damage detection of the CFRP 12 together with the measurement result of the resistance measuring device 24.
Instead of the optical fiber measuring device 46 shown in FIG. 8, an MDM type or OSMOS type measuring device that detects deformation of the optical fiber 44 from a change in the amount of light transmitted through the optical fiber 44 may be used.

When the optical fiber measuring device 46 is a BOTDR measuring instrument, the frequency shift of the Brillouin scattered light depends on the strain change and the temperature change. Therefore, the measurement by the optical fiber measuring device 46 may be performed after the predetermined time has elapsed after the lightning strike, and after the temperature of the CFRP 12 returns to the original, instead of performing the measurement during a lightning stroke in which the temperature of the CFRP 12 rises.
Thereby, the distortion amount of the optical fiber 44 can be detected with high accuracy from the frequency shift of the Brillouin scattered light without being affected by the temperature rise of the optical fiber 44 due to the lightning strike. By comparing the measured value of the distortion amount with a predetermined threshold value in the damage determination unit 42, the presence or absence of damage to the CFRP 12 can be appropriately determined.
It is also possible to specify the strain occurrence position of the optical fiber 44 (that is, the damaged portion of the CFRP 12) from the time until the Brillouin scattered light whose frequency is shifted at the strain occurrence portion of the optical fiber 44 returns to the optical fiber measuring device 46. It is.

Further, as the optical fiber measuring device 46, a BOTDR type measuring instrument and a Bragg grating sensor (FBG) may be used in combination, and the strain change and temperature change of the optical fiber 44 may be detected independently.
FIG. 10 is a diagram showing a configuration example of an optical fiber measuring device 46 using a BOTDR type measuring instrument and a Bragg grating sensor together. In the example shown in the figure, the optical fiber measuring device 46 is connected to the optical fiber 44 through the BOTDR measuring instrument 52, the WDM coupler 54 that connects the BOTDR measuring instrument 52 to the optical fiber 44, and the WDM coupler 54 and the coupler 55. The light source 56 and the optical spectrum analyzer 58 are configured. The optical fiber 44 is provided with a plurality of FBG sensors 50 for performing FBG measurement.
The optical fiber measuring device 46 irradiates a single optical fiber 44 with a laser beam having a wavelength band of 1.55 μm corresponding to BOTDR and a laser beam having a wavelength band of 1.31 μm corresponding to FBG. By measuring the wavelength band of the return light using (WDM: Wavelength Division Multiplexing), both BOTDR and FBG are measured. That is, the laser light (1.55 μm band) output from the BOTDR measuring instrument 52 and the laser light (1.31 μm band) output from the light source 56 are combined by the WDM coupler 54 and incident on the optical fiber 44. The On the other hand, the return light from the optical fiber 44 is demultiplexed into light of two wavelength bands by the WDM coupler 54 and guided to the BOTDR measuring instrument 52 and the optical spectrum analyzer 58, respectively. Then, the BOTDR measuring instrument 52 detects the Brillouin frequency shift, and the optical spectrum analyzer 58 detects the Bragg reflection wavelength shift. Here, the Brillouin frequency shift and the Bragg reflection wavelength shift differ in dependence on strain (see FIG. 11) and dependence on temperature (see FIG. 12). Therefore, using the Brillouin frequency shift detected by the BOTDR measuring instrument 52 and the Bragg reflection wavelength shift detected by the optical spectrum analyzer 58, the strain change and temperature change of the optical fiber 44 can be obtained independently. The strain change and temperature change of the optical fiber 44 obtained in this way are sent to the damage detection unit 36 of the windmill controller 30 and are used to determine the damage of the CFRP 12. For example, the damage detection unit 36 may determine whether the CFRP 12 is damaged by comparing the distortion amount of the optical fiber 44 with a predetermined threshold value or comparing the temperature of the optical fiber 44 with a predetermined threshold value. Good.

  According to the present embodiment, not only the electrical resistance between the measurement electrodes attached to the CFRP 12 but also the scattered light of the light incident on the optical fiber 44 embedded in the CFRP 12 is taken into account. Can be detected with higher accuracy.

  As mentioned above, although embodiment of this invention was described in detail, it cannot be overemphasized that this invention is not limited to this, In the range which does not deviate from the summary of this invention, various improvement and deformation | transformation may be performed.

  For example, in the above-described embodiment, the example in which the wind turbine blade 1 of the wind turbine generator has the configuration described with reference to FIGS. 1 and 2 has been described. However, in the present invention, the configuration of the wind turbine blade is not particularly limited, and is at least partially. May be a wind turbine blade having an arbitrary configuration made of a conductive composite material.

DESCRIPTION OF SYMBOLS 1 Windmill blade 2 Blade root part 4 Tip part 6 Receptor 8 Base plate 10 Outer skin 10a Inner layer 10b Outer layer 12 CFRP (spar cap)
DESCRIPTION OF SYMBOLS 14 Shear web 16 CFRP protective conductor 18 Conductor 20 _i Measuring electrode 20 _i 1st switch 24 Resistance measuring device 26A, 26B Heating electrode 28A, 28B 2nd switch 29 Voltage applicator 30 Windmill controller 31 1st switch control part 32 Measuring instrument control section 33 Second switching control section 34 Voltage application control section 36 Damage detection section 38 Operation mode selection section 44 Optical fiber 46 Optical fiber measuring device 50 FBG sensor 52 BOTDR measuring instrument 54 WDM coupler 55 Coupler 56 Light source 58 Optical spectrum analyzer

Claims (9)

Wind turbine blades at least partially made of a conductive composite material, a plurality of measurement electrodes attached to the conductive composite material, and a resistance measuring instrument connected to each measurement electrode via a first switch An operation control method for a wind turbine generator comprising:
Opening the first switch and operating the wind power generator in a normal operation mode in a state where the resistance measuring instrument is disconnected from the measurement electrode;
When the operation mode of the wind power generator is switched from the normal operation mode to the damage detection mode, the step of closing the first switch and causing the resistance meter to conduct to a pair of electrodes among the measurement electrodes;
Measuring the electrical resistance between the pair of electrodes with the resistance meter while the first switch is closed and the resistance meter is connected to the pair of electrodes;
And a step of detecting damage to the conductive composite material based on the measured value of the electrical resistance. The wind power generator further includes a pair of heating electrodes attached to the conductive composite material, and a voltage applicator connected to the heating electrodes via a second switch,
When the damage detection mode is selected as the operation mode of the wind turbine generator, the second switch is closed, the voltage applicator is conducted to the heating electrode, and the conductive composite material is heated by Joule heat. Further comprising the step of:
2. The operation control method for a wind turbine generator according to claim 1, wherein in the normal operation mode, the state in which the second switch is opened and the voltage applicator is disconnected from the heating electrode is maintained. The conductive composite material extends in the blade length direction of the wind turbine blade, and three or more measurement electrodes are attached to different blade length direction positions,
In the step of measuring the electrical resistance, the electrical resistance is measured for each of the plurality of sets of the pair of electrodes,
The operation control method for a wind turbine generator according to claim 1 or 2, wherein, in the step of detecting the damage, a damaged portion of the conductive composite material is specified based on the electrical resistance of each set. Injecting light into an optical fiber embedded in the conductive composite;
Detecting the scattered light or transmitted light of the light incident on the optical fiber,
The step of detecting damage detects damage of the conductive composite material based on the measured value of the electrical resistance and the scattered light or transmitted light. The operation control method of the described wind turbine generator.   The operation control method for a wind turbine generator according to claim 4, wherein a damaged portion of the conductive composite material is specified based on the scattered light.   The operation of the wind turbine generator according to any one of claims 1 to 5, wherein, when damage to the conductive composite material is detected, at least one of stopping the wind turbine generator and outputting an alarm is performed. Control method.   The wind power generator operation control method according to any one of claims 1 to 6, wherein the conductive composite material is carbon fiber reinforced plastic. A wind turbine generator including wind turbine blades at least partially composed of a conductive composite material,
A plurality of measurement electrodes attached to the conductive composite;
A resistance measuring instrument connected to the measuring electrode via a first switch;
A first opening / closing controller for controlling opening / closing of the first switch;
A measuring instrument controller for controlling the resistance measuring instrument;
Based on the measurement result of the resistance measuring instrument, a damage detection unit that detects damage of the conductive composite material,
As an operation mode of the wind power generator, comprising an operation mode selection unit for selecting any one of a normal operation mode and a damage detection mode,
When the normal operation mode is selected by the operation mode selection unit, the first opening / closing control unit opens the first switch so as to maintain the state where the resistance measuring device is disconnected from the measurement electrode,
When the damage detection mode is selected by the operation mode selection unit, the first opening / closing control unit closes the first switch so that the resistance measuring instrument is connected to a pair of electrodes of the measuring electrode. In addition, the measuring instrument control unit acquires the electrical resistance between the pair of electrodes by the resistance measuring instrument, and the damage detection unit detects damage of the conductive composite material based on the measured value of the electrical resistance. Wind power generator characterized by. The windmill blade includes a spar cap that is provided on a belly side surface and a back side surface of the windmill blade and extends in the blade length direction, and a spar that connects the spar caps on the belly side surface and the back side surface. ,
The conductive composite is the spar cap;
The wind power generator according to claim 8, wherein the measurement electrode is disposed in a region excluding a joint portion with the spar on an inner surface of the spar cap.

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