JP6420451B2 - Wind power generator blade and wind power generator blade inspection method - Google Patents

Description

  The present invention relates to a wind power generator blade and a wind power generator blade inspection method.

  Expectations for renewable energy are increasing more than ever due to the growing awareness of environmental protection and energy issues. Wind power generation is one of the effective means among renewable energies, and safe and stable operation of wind power generators is an important point of wind power generation.

  Among the components that make up a wind power generator, lightning strikes often occur on blades. Generally, a lightning striker (receptor) made of metal that receives lightning is provided at the tip of the blade, and lightning protection is used to release current. A conducting wire is provided so as to extend from the lightning receiving portion to the base of the blade.

  The lightning conductor is often damaged due to a large current and an impact caused by a lightning, and a technique for inspecting the structure of the lightning conductor and its soundness has been proposed for such a situation.

  Patent Document 1 discloses a lightning protection device for a windmill blade in which a lightning power receiving unit is provided on the blade of the windmill so that the lightning current that has been struck is guided to the ground via a lightning conductor, blade hub, and tower. A plurality of lightning power receiving units are prepared, attached to the tip of the lightning conductor, and pushed out (extending) the lightning conductor to guide it through a guide pipe arranged in the blade from the blade hub to a predetermined position on the blade surface. It is moved and fixed at a predetermined position on the surface of the blade, and is configured to be guided and moved through the guide pipe from the predetermined position to the blade hub by pulling out the lightning conductor, and accommodated in the blade hub. Yes.

  Patent Document 2 discloses an inspection signal generator for injecting a step-wave-shaped inspection signal from one end of a lightning conductor to the receptor on the other end in a disconnection detection device for detecting the disconnection of the lightning conductor incorporated in a wind turbine blade. And a measuring device for observing the voltage or current waveform on the lightning conductor side of the inspection signal generator and detecting the lightning conductor wire breakage because the waveform is different from the waveform when the lightning conductor wire is not broken.

JP 2009-250040 A JP2013-29351A

  According to the technique of Patent Document 1, it is possible to replace the lightning power reception unit, but it is necessary to contact the lightning reception unit of a blade installed at a high place in order to inspect whether the lightning conductor is disconnected. The inspection work using an aerial work vehicle takes a lot of labor. In addition, since it is difficult to specify the position of the disconnection, even if the lightning conductor is disconnected at a place where it can be easily repaired, the entire lightning conductor is replaced, and efficient repair is difficult. On the other hand, according to the technique of Patent Document 2, it is necessary to newly develop a dedicated device such as an inspection signal generator for injecting an inspection signal and a measuring device for detecting a waveform. Moreover, the apparatus which detects the presence or absence of the disconnection of the single-line lightning conductor as disclosed in Patent Document 2 is not actually realized.

  The present invention provides a wind power generator blade and a wind power generator blade inspection method capable of simply and efficiently inspecting whether or not a lightning conductor is disconnected.

  The present invention relates to a wind power generator blade for use in a wind power generator, and includes a hollow pipe having an internal space, an outer side of the hollow pipe, and adjacent to the hollow pipe. Provided with a lightning conductor, and the internal space is for inserting a conductor used for inspection of the breakage of the lightning conductor.

  The present invention relates to a blade for a wind power generator used in a wind power generator, and includes a hollow pipe having an internal space and configured as a conductor and acting as a lightning conductor, and the internal space includes the lightning conductor. It is for inserting the conductor used for the inspection of disconnection.

  According to the present invention, it is possible to easily and efficiently inspect the presence or absence of breakage in a lightning conductor and the breakage.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining a wind power generator and a blade for wind power generators, Comprising: (a) is an external view of a wind power generator and a blade for wind power generators, (b) is a BB line in (a). It is sectional drawing of the braid | blade for wind power generators along the line. It is a figure which shows the condition which test | inspects the blade for wind power generators using a TDR inspection apparatus. It is a figure which shows the modification of the braid | blade for wind power generators, (a) is a modification by which a coaxial cable is arrange | positioned, (b) is an enlarged view of a corrugated steel pipe sheathed cable which is a kind of a coaxial cable. (C) is a cross-sectional view of a modified example in which a spare pipe for passing an inspection lead wire is provided.

  Hereinafter, specific embodiments of a wind power generator blade inspection method according to the present invention will be described with reference to the drawings.

  FIG. 1A is an external view of a wind power generator 1. In the wind power generator 1 of this example, three wind power generator blades (hereinafter referred to as “blades”) 10 are provided in a central hub 2. ing. The hub 2 is connected at the upper end of the tower 4 to a generator (not shown) provided inside a nacelle that is rotatably supported in the wind direction.

  FIG.1 (b) is sectional drawing of the braid | blade 10 along the BB line in Fig.1 (a). The blade 10 includes a blade shell 11 constituting an outer shell thereof, and a spar 12 constituting a skeleton. In general, the blade shell 11 and the spar 12 are made of high strength FRP (Fiber Reinforced Plastics) such as GFRP (Glass Fiber Reinforced Plastics) and CFRP (Carbon Fiber Reinforced Plastics). (Reinforced plastic). The blade shell 11 and the spar 12 are connected to each other by an adhesive portion 13 using a predetermined adhesive or the like.

  A large fluid force and centrifugal force are applied to the blade 10 rotating together with the hub 2. Further, lightning strikes often occur on the blade 10. For this reason, a lightning receiving portion (receptor) 15 made of metal that receives lightning is provided at the tip of the blade 10 in a state exposed from the blade shell 11, and a lightning conductor (metal wire, particularly copper wire) 17 for releasing current. Is provided so as to extend from the lightning receiving portion 15 toward the base of the blade 10. The electric potential of the lightning conductor 17 is almost the same as the electric potential of the earth.

  The lightning conductor 17 is often damaged due to a large current and an impact (such as bending in the longitudinal direction of the blade) caused by a lightning strike, and may be disconnected. An arc discharge may also occur inside the blade 10 at the disconnection location, and this energy may cause an unfavorable situation such as gas expansion. In consideration of such a situation, it is desirable that the lightning conductor 17 is inspected easily and efficiently. However, since the blade itself is installed at a high place, it is difficult to make direct contact with the tester or the like. It is often cumbersome to check the continuity, and no appropriate inspection method has been proposed yet.

  In view of such a situation, in the blade 10 of the present embodiment, the lightning conductors 17 connected to the lightning receiver 15 are two (a set of) first lightning conductors 17a arranged substantially parallel to each other. The second lightning conductor 17b is included. In the present embodiment, the first lightning conductor 17a and the second lightning conductor 17b are provided between the blade shell 11 and the spar 12, but their positions are not particularly limited. However, in the present embodiment, the first lightning conductor 17a and the second lightning conductor 17b are arranged in parallel so as to be electrostatically coupled to each other in the entire length region. And, by such a structure provided with at least one set of lightning conductors, the inspection of the lightning conductors becomes simple and efficient.

  FIG. 2 is a diagram illustrating a state in which the blade 10 according to the present embodiment is inspected using the TDR inspection apparatus 20. The TDR inspection apparatus 20 is an apparatus that detects the presence or absence of disconnection of a general metal conductor (conductor) using a TDR (Time Domain Reflectometry) method. The TDR method is a method in which a pulse signal composed of a pulse wave is incident on one end of a conductor such as a lightning conductor, and a reflected wave is observed to measure the characteristic impedance of the conductor. However, in carrying out the TDR method, it is necessary that at least two conductors exist, the two conductors are electrostatically coupled, and a predetermined capacitance is generated. One conductor is to be inspected and the other conductor is to be compared with one conductor in a pseudo manner, thereby obtaining a stable surge impedance (a kind of characteristic impedance) corresponding to the total length of each conductor. it can.

  When the conductor is disconnected for some reason, the surge impedance changes greatly at the location of the disconnection, and a reflected wave of the incident pulse wave is generated. That is, by measuring the observation time when the reflected wave returns, it is possible to inspect for the presence or absence of a conductor breakage.

  Therefore, in the present embodiment, the TDR inspection apparatus 20 generates a pulse wave from the first lightning conductor 17a and the first lightning conductor 17a, assuming that the first lightning conductor 17a is a conductor to be inspected and the second lightning conductor 17b is a conductor to be compared. 2 is incident on the lightning conductor 17b. Then, the TDR inspection device 20 observes the reflected wave of the pulse wave, measures the detected observation time, and determines whether or not the first lightning conductor 17a is disconnected. Alternatively, the first lightning conductor 17a may be regarded as a conductor to be compared, and the second lightning conductor 17b may be regarded as a conductor to be inspected.

The surge impedance and the distance to the conductor breakage point will be described. _Let E _{r be} the magnitude of the reflected wave of the voltage pulse at a certain point on a certain conductor, and E _{i be} the magnitude of the incident wave. The ratio E _r / E _i between E _r and E _i is expressed by the following equation.

In the equation (1), Z _L is the surge impedance on the traveling direction side of the incident wave at a certain point, and Z ₀ is the surge impedance on the opposite side to the traveling direction.

When there are two conductors without disconnection, Z _L = Z _{0 at the} intermediate point, and E _r = 0 from the equation (1). That is, no incident wave is reflected at that point.

However, when Z ₀ represents the surge impedance of two unbroken conductors and Z _L represents the surge impedance at the end, Z _L = ∞ in the open terminal state that is not electrically connected. Equation (2) is established.

From the equations (1) and (2), E _r = E _i . That is, total reflection occurs at the conductor end.

On the other hand, when there is no disconnection in the terminal short-circuit state where the two conductors are electrically connected, Z _L = 0 at the short-circuit portion, and the following expression (3) is established.

  From the equations (1) and (3), Er = −Ei. That is, a reflected wave whose phase is inverted from that of the pulse wave incident at the end of the conductor is generated.

Further, in the conductor to be inspected, the distance from the end where the incident wave is incident to the disconnection point is D, the propagation speed of the pulse wave is v _p , and the observation time from the incidence of the incident wave to the observation of the reflected wave is T. In this case, the following expression (4) is established, and the distance to the end can be determined.

  When D calculated by this equation is shorter than the conductor length, it can be determined that an end exists in the middle of the conductor, that is, a disconnection has occurred.

  In the present embodiment, the entire length of the first lightning conductor 17a or the second lightning conductor 17b (the length from the incident end of the pulse wave to the lightning receiver 15) is regarded as the inspection target area for inspecting whether there is a disconnection. ing. However, it is not always necessary to set the entire length of the lightning conductor to be the inspection target area, and only a part of the first lightning conductor 17a or the second lightning conductor 17b may be used as the inspection area. For example, when the first lightning conductor 17a and the second lightning conductor 17b are electrostatically coupled only from the lightning receiving portion 15 to a half length, the half length can be set as the inspection target region.

  Moreover, in this embodiment, although the 1st lightning conductor 17a and the 2nd lightning conductor 17b are electrically connected in the lightning receiving part 15 in each one end, the 1st lightning conductor 17a and the 2nd It is not always necessary for the lightning conductor 17b to be electrically connected at one end. It is only necessary that the first lightning conductor 17a and the second lightning conductor 17b are electrostatically coupled in at least one of the inspection target areas. In the present embodiment, both the first lightning conductor 17a and the second lightning conductor 17b are electrically connected to the lightning receiver 15 at one end, and both function as a lightning conductor. Even if one of them is disconnected, the position of the disconnection can be grasped.

  In the present embodiment, the first lightning conductor 17a is regarded as a conductor to be inspected and the second lightning conductor 17b is regarded as a conductor to be compared, or the first lightning conductor 17a is a conductor to be compared and the second lightning conductor. The conductor 17b is assumed to be a conductor to be inspected. From this, it can be said that the first lightning conductor is an original lightning conductor and the second lightning conductor 17b is a conductor as a comparison object having a function as a lightning conductor.

  The first lightning conductor 17a and the second lightning conductor 17b can be formed of a single metal wire or a stranded wire.

  FIG. 3 is a view showing a modification of the blade 10. FIG. 3A is a cross-sectional view of the blade 10 in which the coaxial cable 18 having a function as a lightning conductor is disposed. In the present invention, it is sufficient that at least the original lightning conductor and a conductor that is electrostatically coupled to the lightning conductor are present. Therefore, in this modification, the conductor is constituted by a hollow cylindrical body 17c having an internal space, and the first lightning conductor 17a, which is the original lightning conductor, is connected to the cylindrical body 17c, which is a conductor, so as to be electrostatically coupled. Arranged in the internal space of the body 17c. Also with such a configuration, as shown in FIG. 2, it is possible to inspect the first lightning conductor 17a and the cylindrical body 17c with a pulse wave and to inspect the first lightning conductor 17a for disconnection. In addition, it is preferable to arrange | position so that the center point of a cross section may match the 1st lightning conductor 17a and the cylinder 17c so that it may become a concentric form mutually.

  FIG. 3B is an enlarged view of the corrugated steel pipe sheathing cable 18 a which is a kind of coaxial cable, and the corrugated steel pipe sheathing cable 18 a may be disposed on the blade 10. The corrugated steel pipe insulation cable 18a includes an internal cable including the first lightning conductor 17a, a corrugated exchange insulation functioning as a cylindrical body 17c, and an outermost layer 17d having corrosion resistance. The corrugated steel pipe sheathed cable 18a has excellent mechanical strength and high corrosion resistance.

  FIG. 3C is a cross-sectional view of the blade 10 provided with a pipe 19 which is a spare pipe for passing a test conductor. A hollow pipe 19 is provided in advance in the blade 10, a predetermined conductor is inserted into the pipe 19, and then a pulse wave is incident on the first lightning conductor 17a and this conductor by the TDR inspection apparatus 20, The presence or absence of disconnection in the inspection target area of the one lightning conductor 17a can be determined. Even with such a configuration, it is possible to easily and efficiently inspect for the presence or absence of a break in the lightning conductor.

  Further, it is also possible to construct the spare pipe 19 itself with a conductor to provide a lightning conductor. The pipe 19 has a structure in which an inspection conductor can be inserted inside during inspection. Then, when inspecting the lightning conductor, which is a hollow conductor, a conductor such as an inspection cable is inserted into the pipe 19 to form two electrostatically coupled conductors, which are inspected by a TDR inspection apparatus. Can be implemented. In this case, the first lightning conductor 17a can be omitted.

  According to the wind power generator blade and the wind power generator blade inspection method of the present invention, it is possible to determine whether or not the lightning conductor is disconnected and its position without using heavy equipment such as an aerial work vehicle. Wind turbine blades can be inspected simply and efficiently.

  Moreover, since the disconnection position can be clearly identified, only the disconnection portion can be targeted for repair, so that the repair work can be greatly improved in efficiency.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  According to the present invention, there are provided a wind power generator blade and a wind power generator blade inspection method capable of simply and efficiently inspecting the presence or absence of a break in a lightning conductor and the position of a break.

1 wind power generator 2 hub 4 tower 10 blade (blade for wind power generator)
11 Blade shell 12 Spar 13 Adhesive part 15 Lightning receiving part (receptor)
17 Lightning conductor 18 Coaxial cable 19 Pipe

Claims (2)

A blade for a wind power generator used in a wind power generator,
A hollow pipe having an internal space;
A lightning conductor provided outside the hollow pipe and adjacent to the hollow pipe, and
The said internal space is a blade for wind power generators for inserting the conductor used for the inspection of the disconnection of the said lightning conductor. A blade for a wind power generator used in a wind power generator,
Having a hollow pipe that has an internal space and is composed of a conductor and acts as a lightning conductor,
The said internal space is a blade for wind power generators for inserting the conductor used for the inspection of the disconnection of the said lightning conductor.

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