JP2022017021A - Lightning conduction device for windmill blade and wind power generation device - Google Patents

Abstract

To provide a lightning conduction device for windmill blade that can improve a capture rate of lightning and suppress a windmill blade from being broken by a lightning strike.SOLUTION: A lightning conduction device 30 for a windmill blade 12 is installed on the windmill blade 12 of a wind power generation device. The windmill blade 12 includes a lightning reception part 14, a metal conductor 15 which electrically grounds the lightning reception part 14, and a drain hole 16 provided closer to a front end side than the lightning reception part 14. The lightning conduction device 30 for the windmill blade 12 conducts a lightning current to the lightning reception part 14. The lightning conduction device 30 for the windmill blade 12 comprises a first conduction zone 31 which is provided on at least one of a pressure surface and a negative pressure surface 13b of the windmill blade 12, and forms a conduction path for the lightning current. The first conduction zone 31 extends from the side of the lightning reception part 14 toward the drain hole 16.SELECTED DRAWING: Figure 3

Description

Embodiments of the present invention relate to a lightning attracting device for a wind turbine blade and a wind power generation device.

Of the power generation methods that use renewable energy, wind power generation has a relatively large power generation capacity and is attracting attention as one of the power generation methods that can contribute to global warming countermeasures. Currently, wind farms are being constructed, and large-scale wind power generation equipment is becoming mainstream. For example, a wind power generation device in which the height of the tip of a wind turbine blade exceeds 180 m is also known. The wind turbine blade is formed to have a hollow structure by using a material such as glass fiber reinforced plastic from the viewpoint of weight reduction.

The most common cause of damage to wind turbine blades is lightning strikes. Specifically, it is vulnerable to lightning strikes at points with good wind conditions. For this reason, the damage caused by the damage to the wind turbine blades is increasing as the size of the wind power generation device increases.

When the wind turbine blade is hit by a lightning strike, it not only stops the power generation of the wind power generator, but also has to stop the operation for a long time if the damaged part of the wind turbine blade needs to be repaired. Therefore, improvement of the lightning resistance performance of the wind turbine blade has become a problem. It is assumed that a lightning strike will cause direct lightning strikes on transmission and distribution lines or communication lines, or induced lightning strikes due to electromagnetic waves generated by lightning currents, but the most serious damage is direct lightning strikes on wind turbine blades.

On the surface of the conventional wind turbine blade, a metal lightning receiving portion is provided on the wind turbine blade as a lightning protection device. The lightning receiving part is electrically grounded to the ground via a metal lead wire. The metal conductor is located in the hollow portion of the wind turbine blade and is fixed to the wind turbine blade. The lightning strike on the lightning receiving part prevents the wind turbine blade from being struck by lightning.

However, due to the weight reduction of the wind turbine blade, many lightning receiving portions cannot be provided on the wind turbine blade. Therefore, it may not be possible to receive a lightning strike at the lightning receiving portion, and there is a problem that the lightning strike capture rate is low.

Japanese Unexamined Patent Publication No. 2007-100658

The present invention has been made in consideration of such points, and is capable of improving the capture rate of lightning strikes and suppressing damage to the wind turbine blades due to lightning strikes. The purpose is to provide the device.

The lightning attracting device for the wind turbine blade according to the embodiment is installed on the wind turbine blade of the wind power generation device. The wind turbine blade includes a lightning receiving portion, a metal lead wire for electrically grounding the lightning receiving portion, and a drain hole provided at the tip end side of the lightning receiving portion. The lightning attracting device of the wind turbine blade induces a lightning current to the light receiving part. The lightning attracting device for the wind turbine blade is provided on at least one of the pressure surface and the negative pressure surface of the wind turbine blade, and includes a first conductive band forming an induction path of a lightning current. The first conductive band extends from the lightning receiving portion side toward the drain hole.

Further, the wind power generation device according to the embodiment includes a plurality of wind turbine blades and a lightning attracting device for the above-mentioned wind turbine blades installed on the wind turbine blades. The wind turbine blade includes a lightning receiving portion, a metal lead wire for electrically grounding the lightning receiving portion, and a drain hole provided at the tip end side of the lightning receiving portion. The lightning attracting device of the wind turbine blade induces a lightning current to the light receiving part.

According to the present invention, it is possible to improve the capture rate of lightning strikes and suppress damage to the wind turbine blades due to lightning strikes.

FIG. 1 is a side view showing a wind power generator according to the first embodiment. FIG. 2 is a front view of FIG. 1. FIG. 3 is a partially enlarged front view showing a lightning attracting device provided on the wind turbine blade of FIG. 2. FIG. 4 is a cross-sectional view taken along the line AA of FIG. FIG. 5 is an enlarged plan view showing the conductive band of FIG. FIG. 6 is a cross-sectional view taken along the line BB of FIG. FIG. 7 is a diagram for explaining the flow of a lightning strike current that has struck the conductive band of FIG. FIG. 8 is a view showing the lightning attracting device according to the second embodiment, and is a cross-sectional view corresponding to the cross section taken along the line CC of FIG. FIG. 9 is a view showing the lightning attracting device according to the third embodiment, and is a cross-sectional view corresponding to the cross section taken along the line CC of FIG. 10 (a) is a partially enlarged cross-sectional view showing an example of a dissimilar material boundary of FIG. 9, and FIG. 10 (b) is a partially enlarged cross-sectional view showing another example of the dissimilar material boundary of FIG. FIG. 11 is a front view showing the lightning attracting device according to the fourth embodiment. FIG. 12 (a) is a front view showing the state of a lightning strike when the fourth conductive band is not provided, and FIG. 12 (b) shows the state of a lightning strike when the fourth conductive band is provided. It is a front view which shows. FIG. 13 is a diagram for explaining an energization path of a lightning strike current in the lightning strike device of FIG. 11, and is a cross-sectional view corresponding to the cross section taken along the line AA of FIG. FIG. 14 is a graph showing an example of a time waveform of a lightning strike current. FIG. 15 is an equivalent circuit diagram corresponding to the energization path of FIG. FIG. 16 is a front view showing the lightning attracting device according to the fifth embodiment. FIG. 17 is a front view showing the lightning attracting device according to the sixth embodiment. FIG. 18 is a front view showing the lightning attracting device according to the seventh embodiment. FIG. 19 (a) is a front view showing the state of a lightning strike when the auxiliary conductive band is not provided, and FIG. 19 (b) is a front view showing the state of a lightning strike when the auxiliary conductive band is provided. It is a figure.

Hereinafter, the lightning attracting device and the wind power generation device of the wind turbine blade according to the embodiment of the present invention will be described with reference to the drawings.

(First Embodiment)
The lightning attracting device and the wind power generation device of the wind turbine blade in the present embodiment will be described with reference to FIGS. 1 to 7. Here, first, an example of a wind power generation device according to the present embodiment will be described with reference to FIGS. 1 and 2.

As shown in FIGS. 1 and 2, the wind power generation device 1 includes a rotary blade 10 for a wind turbine, a nacelle 2, a lightning rod 3, and a tower 4.

The rotary blade 10 for a wind turbine is rotatable about a central axis extending in the horizontal direction of the nacelle 2. The rotary blade 10 for a wind turbine rotates when it receives wind. As shown in FIG. 2, the rotary blade 10 for a wind turbine is configured to rotate in a clockwise direction when viewed from the front, but the rotational direction of the rotary blade 10 for a wind turbine is not limited to this. do not have.

A generator (not shown) is housed in the nacelle 2, and power is generated by the rotation of the rotary blade 10 for a wind turbine. Although not shown, the nacelle 2 houses a brake for stopping the rotation of the rotary blade 10 for a wind turbine and a rotation sensor for detecting the rotation angle (or rotation position) of the rotary blade 10 for a wind turbine.

As shown in FIG. 1, the lightning rod 3 is attached to the upper surface of the nacelle 2. The lightning rod 3 is intended to protect the nacelle 2 and the generator in the nacelle 2 from lightning strikes, but is not intended to protect the wind turbine blade 12 described later of the wind turbine rotor blade 10 from lightning strikes.

Tower 4 stands up from the ground and supports nacelle 2. The nacelle 2 is rotatable about an axis extending in the vertical direction with respect to the tower 4. The rotor blade 10 for a wind turbine is supported by the tower 4 via the nacelle 2.

As shown in FIGS. 1 and 2, the wind turbine rotor blade 10 includes a hub 11 connected to a generator and three wind turbine blades 12 connected to the hub 11. The hub 11 and each wind turbine blade 12 are formed so as to rotate integrally. The number of wind turbine blades 12 is not limited to three and is arbitrary.

As shown in FIGS. 3 and 4, the wind turbine blade 12 includes a blade main body 13, a lightning receiving portion 14, a metal lead wire 15, and a drain hole 16.

The blade body 13 has an airfoil shape. One surface of the blade body 13 is configured as a pressure surface 13a, and the other surface is configured as a negative pressure surface 13b. In FIG. 3, the negative pressure surface 13b is shown. In FIG. 4, the pressure surface 13a is shown on the lower side and the negative pressure surface 13b is shown on the upper side.

As shown in FIG. 3, the blade body 13 includes a leading edge 17 and a trailing edge 18. As shown in FIG. 2, the leading edge 17 is located on the traveling side of the rotary blade 10 for a wind turbine in the rotational direction, and the trailing edge 18 is located on the side opposite to the rotational direction. As shown in FIG. 4, the blade main body 13 has a hollow portion 19 and is made of an insulating material such as glass fiber reinforced plastic.

The blade body 13 is formed by abutting the pressure surface side blade portion 13c located on the side of the pressure surface 13a and the negative pressure surface side blade portion 13d located on the side of the negative pressure surface 13b. The leading edge 17 and the trailing edge 18 of the blade body 13 described above correspond to a portion where the pressure surface side blade portion 13c and the negative pressure surface side blade portion 13d are butted against each other. The pressure surface side blade portion 13c and the negative pressure surface side blade portion 13d are bonded to each other with an adhesive. A beam member 13e (see FIG. 8) is provided in the hollow portion 19, and the beam member 13e is connected to the pressure surface side blade portion 13c and the negative pressure surface side blade portion 13d.

The lightning receiving portion 14 is provided in the tip end side region of the blade main body 13. As shown in FIG. 4, the lightning receiving portion 14 is embedded in the pressure surface side blade portion 13c and the negative pressure surface side blade portion 13d, respectively. The lightning receiving portion 14 embedded in the pressure surface side blade portion 13c is exposed from the pressure surface 13a. The pressure surface 13a and the surface of the lightning receiving portion 14 form substantially continuous surfaces. Similarly, the lightning receiving portion 14 embedded in the negative pressure surface side blade portion 13d is exposed from the negative pressure surface 13b. The negative pressure surface 13b and the surface of the lightning receiving portion 14 form substantially continuous surfaces. The lightning receiving portion 14 is formed in a disk shape using a conductive metal material. The lightning receiving portion 14 is sometimes called a receptor.

Here, the types of the lightning receiving unit will be described. In general, there are multiple types of lightning receiving parts. For example, a tip type, a rod type, and a disc type can be mentioned. The chip-type power receiving portion is configured as a member made of a solid metal material formed on the surface of the tip portion of the wind turbine blade 12. The chip-type power receiving unit exposes the metal material in a relatively wide area including the tip of the wind turbine blade 12. In the rod type, a rod-like member made of a metal material extends to the tip of the wind turbine blade 12 at the tip of the metal conductor 15 described later, and this member is exposed to the outside by the tip of the wind turbine blade 12. .. The lightning receiving unit 14 in the present embodiment is a disk-type receptor. In the disc type, a disk-shaped lightning receiving portion 14 is connected to the tip of the metal conducting wire 15 via a connecting member 20 described later, and the lightning receiving portion 14 is exposed to the outside.

The lightning receiving portion 14 provided on the pressure surface side blade portion 13c and the lightning receiving portion 14 provided on the negative pressure surface side blade portion 13d are connected by a connecting member 20. The connecting member 20 is formed by using a conductive metal material.

The metal conductor 15 is connected to the connecting member 20. The metal conductor 15 is electrically grounded to the ground, and the lightning receiving portion 14 is electrically grounded via the connecting member 20. The metal conductor 15 is located in the hollow portion 19 of the blade main body 13. As shown in FIG. 3, when viewed from the front of the wind power generator 1, the metal conductor 15 is located at an intermediate position between the leading edge 17 and the trailing edge 18 of the blade body 13, and the beam member 13e (FIG. 8). See). The metal conductor 15 may be referred to as a down conductor.

The drain hole 16 is provided on the side of the blade main body 13 on the tip 13t side of the lightning receiving portion 14. That is, the drain hole 16 is located in the vicinity of the tip 13t of the blade main body 13. The drain holes 16 are formed in the pressure surface side blade portion 13c and the negative pressure surface side blade portion 13d, respectively. The water in the hollow portion 19 can be discharged to the outside from the drain hole 16. The planar shape of the drain hole 16 may be circular.

Next, the lightning attracting device for the wind turbine blade according to the present embodiment (hereinafter, simply referred to as a lightning attracting device 30) will be described with reference to FIGS. 3 to 6. The lightning strike device 30 is a device installed on the wind turbine blade 12 for inducing a lightning strike current to the lightning receiving portion 14.

As shown in FIGS. 3 and 4, the lightning attracting device 30 according to the present embodiment includes a first conductive band 31, a second conductive band 32, and a third conductive band 33. The first conductive band 31, the second conductive band 32, and the third conductive band 33 are provided on the pressure surface 13a and the negative pressure surface 13b of the blade main body 13, respectively. Each of the conductive bands 31 to 33 forms an induction path for a lightning strike current to the lightning receiving portion 14. The conductive bands 31 to 33 provided on the pressure surface 13a and the conductive bands 31 to 33 provided on the negative pressure surface 13b are substantially the same. Here, typically, each of the conductive bands 31 to 33 provided on the negative pressure surface 13b will be described, and the description of each of the conductive bands 31 to 33 provided on the pressure surface 13a will be omitted.

As shown in FIG. 3, the first conductive band 31 extends from the lightning receiving portion 14 side toward the drain hole 16. The first conductive band 31 forms an induction path for a lightning strike current from the vicinity of the drain hole 16 to the lightning receiving portion 14. In the present embodiment, the tip of the first conductive band 31 is located closer to the lightning receiving portion 14 than the drain hole 16. That is, the tip of the first conductive band 31 is located in the vicinity of the drain hole 16, and the tip of the first conductive band 31 and the drain hole 16 are separated from each other.

The second conductive band 32 extends from the lightning receiving portion 14 side so as to be along the leading edge 17 of the blade main body 13 on the side opposite to the tip 13t of the blade main body 13 (or the base end side) of the lightning receiving portion 14. ing. In the present embodiment, the second conductive band 32 forms an induction path for a lightning strike current from the vicinity of the leading edge 17 to the lightning receiving portion 14.

More specifically, the second conductive band 32 has a second conductive band main body portion 32a located along the leading edge 17 of the blade main body 13 and a second conductive band main body portion 32a toward the lightning receiving portion 14. Includes a second conductive band connecting portion 32b that extends. The second conductive band main body portion 32a is located closer to the hub 11 than the lightning receiving portion 14. The second conductive band main body portion 32a according to the present embodiment is located in the vicinity of the leading edge 17. The second conductive band main body portion 32a and the second conductive band connecting portion 32b are integrally formed with an insulating layer 41 described later in a continuous manner. Conductive pieces 40, which will be described later, are arranged on the insulating layer 41 with a gap. The second conductive band connecting portion 32b is formed in a curved shape, and forms a smooth induction path for a lightning strike current.

The third conductive band 33 extends from the lightning receiving portion 14 on the side opposite to the tip 13t of the blade main body 13 and along the trailing edge 18 of the blade main body 13 with respect to the lightning receiving portion 14. In the present embodiment, the third conductive band 33 forms an induction path for a lightning strike current from the vicinity of the trailing edge 18 to the lightning receiving portion 14.

More specifically, the third conductive band 33 has a third conductive band main body 33a located along the trailing edge 18 of the blade main body 13 and a third conductive band main body 33a toward the lightning receiving portion 14. Includes a third conductive band connecting portion 33b that extends. The third conductive band main body portion 33a is located closer to the hub 11 than the lightning receiving portion 14. The third conductive band main body 33a according to the present embodiment is located in the vicinity of the trailing edge 18. The third conductive band main body portion 33a and the third conductive band connecting portion 33b are integrally formed with an insulating layer 41 described later in a continuous manner. Conductive pieces 40, which will be described later, are arranged on the insulating layer 41 with a gap. The third conductive band connecting portion 33b is formed in a curved shape, and forms a smooth induction path for a lightning strike current.

As shown in FIGS. 5 and 6, the first conductive band 31, the second conductive band 32, and the third conductive band 33 each include a plurality of conductive pieces 40 and an insulating layer 41. A plurality of conductive pieces 40 are fixed on the insulating layer 41. The conductive piece 40 may be made of a metal material having a high melting point. The conductive piece 40 may be formed in a plate shape. The planar shape of the conductive piece 40 may be rectangular as shown in FIG. 5, but is not limited to this, and is arbitrary. The conductive piece 40 may be adhered to the insulating layer 41 using, for example, an adhesive. The plurality of conductive pieces 40 are arranged via the gap g1 in the extending direction of the corresponding conductive bands 31 to 33. Each of the conductive bands 31 to 33 is configured by arranging and fixing a plurality of conductive pieces 40 on the insulating layer 41. The insulating layer 41 of each of the conductive bands 31 to 33 may be adhered to the blade main body 13 using, for example, an adhesive. A plurality of conductive pieces 40 may be bonded in advance on the insulating layer 41, and then the insulating layer 41 may be bonded to the blade main body 13. The gap g1 is preferably small in order to facilitate arc discharge between the conductive pieces 40 adjacent to each other. On the other hand, it is preferable that the conductive pieces 40 are large to some extent in order to prevent welding between the conductive pieces 40 due to arc discharge. For example, the gap g1 is preferably 1 mm or more and 5 mm or less, and more preferably 1 mm or more and 3 mm or less.

As shown in FIG. 5, among the plurality of conductive pieces 40 of the first conductive band 31, the conductive piece 40 located closest to the lightning receiving portion 14 is arranged with respect to the lightning receiving portion 14 via a predetermined gap g2. Has been done. This gap g2 may be equal to, for example, the above-mentioned gap g1. The same applies to the second conductive band 32 and the third conductive band 33.

The base end of the insulating layer 41 constituting the first conductive band 31 located on the lightning receiving portion 14 side may be in contact with or separated from the lightning receiving portion 14. The same applies to the second conductive band 32 and the third conductive band 33.

Of the plurality of conductive pieces 40 constituting the first conductive band 31, the conductive piece 40 located closest to the drain hole 16 is arranged with respect to the drain hole 16 via a predetermined gap g3. The gap g3 may be larger than the above-mentioned gap g1. The gap g3 is preferably small in order to increase the lightning strike capture rate. On the other hand, in order to prevent corrosion by the water discharged from the drain hole 16, it is preferable that the size is large to some extent. For example, the gap g3 is preferably 10 mm or more and 100 mm or less, and more preferably 10 mm or more and 50 mm or less. Further, the end of the insulating layer 41 constituting the first conductive band 31 located on the side of the drain hole 16 is arranged with respect to the drain hole 16 via a predetermined gap g4. The gap g4 may be smaller than the gap g3.

Next, a case where a lightning strike occurs on the wind turbine blade 12 in which the lightning attracting device 30 according to the present embodiment having such a configuration is installed will be described.

Generally, a lightning streamer from a thundercloud toward the wind turbine blade 12 tends to land on the tip end side region of the blade body 13. This is because the curvature of the tip side region is large, and electric lines of force are likely to be concentrated in the tip side region. In the present embodiment, the first conductive band 31, the second conductive band 32, and the third conductive band 33 constituting the lightning attracting device 30 are provided around the lightning receiving portion 14 located in the tip end side region of the blade main body 13. Has been done. When the lightning strike streamer advances toward the tip side region of the blade body 13, any of the conductive bands 31 to 33 may catch the lightning strike.

For example, as shown in FIG. 7, when a lightning strike streamer S lands on the first conductive band 31, a lightning current I ₀ is guided toward the light receiving portion 14 in the first conductive band 31. In this case, the lightning current I ₀ is arc-discharged in the gap g1 formed between the conductive pieces 40 adjacent to each other. As a result, the lightning current I ₀ is guided toward the lightning receiving portion 14 while attenuating the energy. Further, the lightning current I ₀ is also arc-discharged even in the gap g2 (see FIG. 5) between the conductive piece 40 located closest to the lightning receiving portion 14 and the lightning receiving portion 14. The lightning strike current I ₀ flows from the lightning receiving portion 14 to the ground through the connecting member 20 and the metal lead wire 15 (see FIG. 13 described later). The same applies to the second conductive band 32 and the third conductive band 33.

Here, conventionally, it has been considered that a lightning striker is likely to land on the tip 13t of the tip side region of the blade main body 13. Now, the inventors have easily landed a water drain hole 16 located in the vicinity of the tip 13t of the blade body 13 in the region on the tip side of the blade body 13, and the lightning strike is not captured by the lightning receiving portion 14 and is drained. Experiments have shown that there are many lightning strikes in hole 16. The first conductive band 31 according to the present embodiment extends toward the drain hole 16, and the tip of the first conductive band 31 is located in the vicinity of the drain hole 16. As a result, the lightning strike that reaches the drain hole 16 can be captured by the first conductive band 31. The captured lightning strike is guided to the lightning receiving portion 14 by the first conductive band 31.

Further, in the region on the tip end side of the blade body 13, the leading edge 17 and the trailing edge 18 are also prone to lightning. The second conductive band 32 according to the present embodiment extends from the lightning receiving portion 14 side to a position along the leading edge 17. As a result, the lightning strike that reaches the leading edge 17 can be captured by the second conductive band 32. The lightning strike current is guided to the lightning receiving portion 14 by the second conductive band 32. Further, the third conductive band 33 according to the present embodiment extends from the lightning receiving portion 14 side to a position along the trailing edge 18. As a result, the lightning strike that reaches the trailing edge 18 can be captured by the third conductive band 33. The lightning strike current is guided to the lightning receiving portion 14 by the third conductive band 33.

As described above, according to the present embodiment, the first conductive band 31 of the lightning attracting device 30 extends from the side of the lightning receiving portion 14 toward the drain hole 16. As a result, even when the lightning streamer advances toward the drain hole 16 of the wind turbine blade 12 which is easy to lightning, the lightning strike can be captured by the first conductive band 31. In this case, the lightning strike current can be guided from the first conductive band 31 to the lightning receiving portion 14, and can be safely flowed to the ground. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 (for example, damage to the drain hole 16) due to a lightning strike can be suppressed.

Further, according to the present embodiment, the tip of the first conductive band 31 is located closer to the lightning receiving portion 14 than the drain hole 16. This makes it possible to form a gap between the tip of the first conductive band 31 and the drain hole 16. In this case, it is possible to prevent the first conductive band 31 from being corroded by the water discharged from the drain hole 16.

Further, according to the present embodiment, the first conductive band 31 includes a plurality of conductive pieces 40 arranged through the gap. This allows arc discharge in the gap while the lightning current is being induced in the first conductive band 31. Therefore, the energy of the lightning strike current can be attenuated, and the lightning strike current can be safely flowed to the ground. That is, when the lightning strike current passes through the blade main body 13 without being guided to the lightning receiving portion 14, the lightning strike current arc discharges in the hollow portion 19 and reaches the metal conducting wire 15. In this case, the air pressure in the hollow portion 19 rises due to the heat of the arc discharge, and the blade main body 13 may be damaged. However, according to the present embodiment, the energy of the lightning strike current can be attenuated by generating an arc discharge in the gap between the conductive pieces 40. Therefore, it is possible to suppress the occurrence of arc discharge in the hollow portion 19, and it is possible to suppress the damage of the blade main body 13.

Further, according to the present embodiment, the second conductive band 32 is on the opposite side of the lightning receiving portion 14 from the tip 13t of the blade main body 13 and is along the leading edge 17 of the wind turbine blade 12. It extends from the side of 14. As a result, even when the lightning strike streamer advances toward the leading edge 17 of the wind turbine blade 12, the lightning strike can be captured by the second conductive band 32. In this case, the lightning strike current can be guided from the second conductive band 32 to the lightning receiving portion 14, and can be safely flowed to the ground. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 due to lightning strikes can be suppressed.

Further, according to the present embodiment, the third conductive band 33 is on the opposite side of the lightning receiving portion 14 from the tip 13t of the blade main body 13 and is along the trailing edge 18 of the wind turbine blade 12. It extends from the side of 14. As a result, even when the lightning strike streamer advances toward the trailing edge 18 of the wind turbine blade 12, the lightning strike can be captured by the third conductive band 33. In this case, the lightning strike current can be guided from the third conductive band 33 to the lightning receiving portion 14, and can be safely flowed to the ground. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 due to lightning strikes can be suppressed.

In the above-described embodiment, the first conductive band 31, the second conductive band 32, and the third conductive band 33 are provided on the pressure surface 13a and the negative pressure surface 13b of the blade main body 13, respectively. explained. However, the present invention is not limited to this, and the conductive bands 31 to 33 may be provided on either the pressure surface 13a or the negative pressure surface 13b of the blade main body 13 and may not be provided on the other. In this case, the second conductive band 32 and the third conductive band 33 may be provided on the surface of the pressure surface 13a and the negative pressure surface 13b of the blade main body 13 where the first conductive band 31 is provided. That is, the second conductive band 32 and the third conductive band 33 are provided on the same surface as the surface on which the first conductive band 31 is provided.

Further, in the above-described embodiment, an example in which each of the conductive bands 31 to 33 includes a plurality of conductive pieces 40 via a gap has been described. However, the present invention is not limited to this, and the conductive bands 31 to 33 may be continuously formed by one conductive piece 40 depending on the energy of the assumed lightning strike.

Further, in the above-described embodiment, the example in which the tip of the first conductive band 31 is located closer to the lightning receiving portion 14 than the drain hole 16 has been described. However, the present invention is not limited to this, and the tip of the first conductive band 31 may be in contact with the drain hole 16. Alternatively, the first conductive band 31 may extend beyond the drain hole 16 and the tip of the first conductive band 31 may be located closer to the tip 13t of the blade body 13 than the drain hole 16.

(Second embodiment)
Next, the lightning attracting device and the wind power generation device of the wind turbine blade according to the second embodiment will be described with reference to FIG.

The second embodiment shown in FIG. 8 is mainly different in that the third conductive band is located along the leading edge of the filling portion provided in the hollow portion of the wind turbine blade, and has another configuration. Is substantially the same as the first embodiment shown in FIGS. 1 to 7. In FIG. 8, the same parts as those of the first embodiment shown in FIGS. 1 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 8, in the present embodiment, the filling portion 50 is provided in the hollow portion 19 of the blade main body 13. The filling portion 50 is located in the hollow portion 19 on the side of the trailing edge 18 of the blade main body 13. The filling portion 50 extends in the longitudinal direction of the blade body 13. The longitudinal direction of the blade body 13 corresponds to the direction perpendicular to the paper surface of FIG. 8, and corresponds to the radial direction of the rotary blade 10 for a wind turbine. The filling portion 50 is formed by the adhesive used for bonding the pressure surface side blade portion 13c and the negative pressure surface side blade portion 13d protruding into the hollow portion 19. The filling portion 50 includes a filling portion leading edge 51 located on the side of the leading edge 17 of the blade main body 13. The leading edge 51 of the filling portion also extends in the longitudinal direction of the blade body 13.

The third conductive band 33 according to the present embodiment is located along the leading edge 51 of the filling portion. In other words, it is located along the boundary between the filling portion 50 and the space indicated by the hollow portion 19 when viewed from the pressure surface 13a and the negative pressure surface 13b of the blade main body 13. For example, the third conductive band 33 provided on the pressure surface side blade portion 13c may overlap the leading edge 51 of the filling portion when viewed from the front of the wind power generation device 1. Further, the third conductive band 33 provided on the negative pressure surface side blade portion 13d may overlap the leading edge 51 of the filling portion when viewed from the front of the wind power generation device 1.

As described above, the leading edge 17 and the trailing edge 18 of the blade body 13 also tend to be subject to lightning, but the curvature of the blade body 13 is larger at the trailing edge 18 than at the leading edge 17. Therefore, at the trailing edge 18, the electric lines of force are more likely to be concentrated than at the leading edge 17, and lightning strikes are more likely to occur. Since the filling portion 50 described above is provided on the portion of the hollow portion 19 on the side of the trailing edge 18, the leading edge 51 of the filling portion tends to cause a lightning strike.

The third conductive band 33 according to the present embodiment is located along the leading edge 51 of the filling portion. As a result, the lightning strike that reaches the leading edge 51 of the filling portion can be captured by the third conductive band 33. The lightning strike current is guided to the lightning receiving portion 14 by the third conductive band 33. When the third conductive band 33 overlaps the leading edge 51 of the filling portion, the capture rate of lightning strikes reaching the leading edge 51 of the filling portion can be improved.

As described above, according to the present embodiment, the third conductive band 33 is located along the leading edge 51 of the filling portion. As a result, even when the lightning strike streamer advances toward the leading edge 51 of the filling portion, the lightning strike can be captured by the third conductive band 33. In this case, the lightning strike current can be guided from the third conductive band 33 to the lightning receiving portion 14, and can be safely flowed to the ground. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 due to lightning strikes can be suppressed.

(Third embodiment)
Next, the lightning attracting device and the wind power generation device of the wind turbine blade according to the third embodiment will be described with reference to FIGS. 9 and 10.

In the third embodiment shown in FIGS. 9 and 10, the point that the third conductive band is located along the boundary between different materials that separates the two portions formed of different structural materials is mainly. Unlike the other configurations, they are substantially the same as the second embodiment shown in FIG. In FIGS. 9 and 10, the same parts as those of the second embodiment shown in FIG. 8 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 9, in the present embodiment, the blade body 13 includes a dissimilar material boundary 60 that separates two portions formed of different structural materials. For example, a high-strength material may be used for a portion of the blade body 13 that requires mechanical strength, and a structural material for giving priority to weight reduction may be used for other portions. Therefore, the blade main body 13 may be formed of different structural materials.

More specifically, as shown in FIGS. 10A and 10B, the negative pressure surface side blade portion 13d has a first material portion 61 formed of the first structural material and a first structure. It includes a second material portion 62, which is made of a second structural material different from the material. The boundary between the first material portion 61 and the second material portion 62 corresponds to the dissimilar material boundary 60. FIG. 10A shows, as an example, an example in which the first material portion 61 located on the side of the trailing edge 18 and the second material portion 62 located on the side of the leading edge 17 are butted against each other. There is. The mating surface constitutes the dissimilar material boundary 60, and electric lines of force are easily concentrated at the dissimilar material boundary 60. As another example, FIG. 10B shows an example in which the second material portion 62 is embedded in the first material portion 61. The edge on the side of the trailing edge 18 of the second material portion 62 constitutes the dissimilar material boundary 60, and electric lines of force are easily concentrated at the dissimilar material boundary 60. 10 (a) and 10 (b) show an example of the dissimilar material boundary 60 provided on the negative pressure surface side blade portion 13d, but the same dissimilar material boundary 60 is also provided on the pressure surface side blade portion 13c. Is formed. The dissimilar material boundary 60 extends in the longitudinal direction of the blade body 13.

The third conductive band 33 according to the present embodiment is located along the dissimilar material boundary 60. For example, even if the third conductive band 33 provided on the pressure surface side blade portion 13c overlaps the dissimilar material boundary 60 provided on the pressure surface side blade portion 13c when viewed from the front of the wind power generation device 1. good. Further, even if the third conductive band 33 provided on the negative pressure surface side blade portion 13d overlaps the dissimilar material boundary 60 provided on the negative pressure surface side blade portion 13d when viewed from the front of the wind power generation device 1. good.

As described above, electric lines of force tend to be concentrated at the boundary 60 of different materials, and lightning strikes tend to occur.

The third conductive band 33 according to the present embodiment is located along the dissimilar material boundary 60. As a result, the lightning strike that reaches the dissimilar material boundary 60 can be captured by the third conductive band 33. The lightning strike current is guided to the lightning receiving portion 14 by the third conductive band 33. When the third conductive band 33 overlaps the dissimilar material boundary 60, the capture rate of lightning strikes reaching the dissimilar material boundary 60 can be improved. By capturing the lightning strike with the third conductive band 33 in this way, it is possible to prevent the lightning strike current from being arc-discharged from the blade main body 13 and reaching the metal conductor wire 15. Therefore, it is possible to prevent the blade main body 13 from being damaged due to an increase in the air pressure in the hollow portion 19.

As described above, according to the present embodiment, the third conductive band 33 is located along the boundary 60 between different materials. As a result, even when the lightning strike streamer progresses toward the boundary 60 of different materials, the lightning strike can be captured by the third conductive band 33. In this case, the lightning strike current can be guided from the third conductive band 33 to the lightning receiving portion 14, and can be safely flowed to the ground. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 due to lightning strikes can be suppressed.

In the present embodiment described above, an example in which the third conductive band 33 is located along the boundary 60 of different materials that separates two portions formed of different structural materials has been described. However, this is not limited to this. For example, in order to reduce the weight, it is conceivable that the blade hollow portion 63 is formed in the blade main body 13 instead of the above-mentioned second material portion 62. In this case, instead of the dissimilar material boundary 60, a boundary (structural material thickness boundary 64) in which the thickness of the structural material constituting the blade body 13 changes is formed in the blade body 13. Of the blade portion 13d on the negative pressure surface side, the portion where the blade hollow portion 63 is formed is hollow, so that the thickness of the structural material is smaller than the portion where the blade hollow portion 63 is not formed. The third conductive band 33 may be located along the structural material thickness boundary 64. Even when the lightning striker progresses toward the structural material thickness boundary 64, the lightning strike can be captured by the third conductive band 33.

(Fourth Embodiment)
Next, the lightning attracting device and the wind power generation device of the wind turbine blade according to the fourth embodiment will be described with reference to FIGS. 11 to 15.

In the fourth embodiment shown in FIGS. 11 to 15, the point that the fourth conductive band is provided between the metal conducting wire and the third conductive band when viewed from the front of the wind power generation device is mainly. Unlike the other configurations, the other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 7. In FIGS. 11 to 15, the same parts as those of the first embodiment shown in FIGS. 1 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 11, the lightning attracting device 30 in the present embodiment further includes a fourth conductive band 70. The fourth conductive band 70 is provided on the surface of the pressure surface 13a and the negative pressure surface 13b of the blade main body 13 where the third conductive band 33 is provided. In the present embodiment, the fourth conductive band 70 is provided on each of the pressure surface 13a and the negative pressure surface 13b of the blade main body 13. The fourth conductive band 70 forms an induction path for a lightning strike current to the lightning receiving portion 14. The fourth conductive band 70 is formed so as to induce a lightning strike current to the lightning receiving portion 14. Like the first to third conductive bands 33, the fourth conductive band 70 includes an insulating layer 41 and a plurality of conductive pieces 40 arranged via the gap g1. In FIG. 11, the fourth conductive band 70 is shown with substantially the same length as the second conductive band 32 and the third conductive band 33 in the longitudinal direction of the blade main body 13. However, the fourth conductive band 70 may be shorter than the second conductive band 32 and the third conductive band 33.

The fourth conductive band 70 is located on the side opposite to the tip of the blade main body 13 with respect to the lightning receiving portion 14, and is between the metal conductor 15 and the third conductive band 33 when viewed from the front of the wind power generation device 1. Is located in.

More specifically, the fourth conductive band 70 has a fourth conductive band main body 70a located along the metal conducting wire 15 and a fourth conductive band extending from the fourth conductive band main body 70a toward the lightning receiving portion 14. The band connection portion 70b and the like are included. The fourth conductive band main body 70a is located between the third conductive band 33 and the metal conducting wire 15 when viewed from the front of the wind power generation device 1. In the fourth conductive band main body portion 70a and the fourth conductive band connecting portion 70b, the insulating layer 41 is continuously integrally formed. Conductive pieces 40 are arranged on the insulating layer 41 with a gap. The fourth conductive band connecting portion 70b is formed in a curved shape, and forms a smooth induction path for a lightning strike current.

Here, as shown in FIG. 12A, when the above-mentioned fourth conductive band 70 is not provided on the negative pressure surface 13b of the blade main body 13, the leading edge 17 and the trailing edge 18 of the blade main body 13 are formed. A lightning strike streamer S that has advanced toward the central region located between them lands on the central region of the blade body 13. In this case, the lightning strike current can pass through the negative pressure surface side blade portion 13d of the blade main body 13 and be arc-discharged to reach the metal conductor 15 located in the hollow portion 19.

More specifically, as shown in FIG. 13, when the lightning strike streamer S hits the point E, the lightning current I1 passes through the blade portion on the negative pressure surface 13b _side and enters the hollow portion 19. Then, the lightning current I ₁ is arc-discharged in the hollow portion 19 and reaches the metal conducting wire 15. At this time, the air pressure in the hollow portion 19 rises due to the heat of this arc discharge. This can damage the blade body 13.

On the other hand, in the present embodiment, as shown in FIG. 12B, when the fourth conductive band 70 is provided on the negative pressure surface 13b, the lightning streamer S reaching the central region of the blade body 13 is Lightning strikes the fourth conductive band 70. As shown in FIG. 13, the lightning current I ₂ is guided to the lightning receiving portion 14 by the fourth conductive band 70. Then, the lightning strike current I ₂ reaches the metal conductor 15 from the lightning receiving portion 14 through the connecting member 20, and flows toward the ground.

FIG. 14 is a graph showing an example of a time waveform of a current value of a lightning strike current. The current value I is expressed as a function of time t as shown in equation (1). The rising time of the normal current value I is from several microseconds to several tens of microseconds, which is relatively short. On the other hand, the current value I after exceeding the maximum current value Im gradually decreases relatively slowly.

FIG. 15 is an equivalent circuit diagram corresponding to the energization path of FIG. Assuming that the electric resistance of the fourth conductive band 70 is R ₁ , the electric resistance of the metal conductor 15 from the light receiving portion 14 to the point F is R ₂ , and the circuit inductance is L ₁ , it is generated between the points E and F. The voltage _VEF is given by the following equation (2). R ₃ indicates the electrical resistance of the metal conductor 15 from the point F to the ground.

As shown in FIG. 14, when the current value I rises, the time change of the lightning current is particularly rapid. In this case, the value of the first term on the right side of the equation ( ₂ ) becomes large due to the influence of the circuit inductance L1. Therefore, as shown in FIG. 15, it becomes difficult for the current path P1 composed of the fourth conductive band 70, the lightning receiving portion 14, the connecting member 20, and the metal conducting wire ₁₅ to flow. When the VEF shown on the left side of the equation (2) exceeds the dielectric breakdown _voltage in the hollow portion 19, _no lightning current flows through the energization path P1 and the metal lead wire is arc-discharged in the hollow portion 19. Reach 15 For example, depending on the positional relationship between the fourth conductive band 70 and the metal conducting wire 15 and the time characteristics of the lightning current included in the lightning streamer, the lightning current does not flow through the intended current _- carrying path P1 but follows the current _- carrying path P2. It flows.

In order to induce the lightning strike current from the point E to the lightning receiving portion 14, an equivalent circuit is provided so that the VEF represented by the equation (2) does not exceed the dielectric breakdown voltage in the _hollow portion 19 at the assumed lightning strike current. You can design it. Whether or not this is satisfied can be greatly affected by the distance between the fourth conductive band 70 and the metal conducting wire 15. That is, the distance between the fourth conductive band 70 and the metal conductor 15 may be set so that the _VEF represented by the equation (2) does not exceed the dielectric breakdown voltage in the hollow portion 19. As a result, the lightning strike current can be guided to the lightning receiving portion 14 by the fourth conductive band 70, and the occurrence of arc discharge in the hollow portion 19 can be suppressed.

From the viewpoint of weight reduction, glass fiber reinforced plastic (hereinafter referred to as GFRP) is often used as the material of the blade body 13. In order to increase the strength as well as the weight, carbon fiber reinforced plastic (hereinafter referred to as CFRP) may be used as the material of the beam material 13e (see FIG. 8). While GFRP has electrical insulation, CFRP has conductivity. Therefore, the arrangement of the fourth conductive band 70 may consider not only the distance from the metal conducting wire 15 but also the distance from the beam member 13e formed of CFRP.

As described above, according to the present embodiment, the fourth conductive band 70 is located between the metal conducting wire 15 and the third conductive band 33 when viewed from the front of the wind power generation device 1. As a result, even when a lightning strike streamer extends to the central region between the leading edge 17 and the trailing edge 18 of the wind turbine blade 12, the lightning strike can be captured by the fourth conductive band 70. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 due to lightning strikes can be suppressed.

Further, according to the present embodiment, the fourth conductive band 70 can be kept away from the metal conducting wire 15. Therefore, even when a lightning strike occurs in the fourth conductive band 70, it is possible to prevent the lightning strike current from being arc-discharged from the blade main body 13 and reaching the metal conductor wire 15. As a result, it is possible to prevent the blade body 13 from being damaged due to an increase in the air pressure in the hollow portion 19.

(Fifth Embodiment)
Next, with reference to FIG. 16, the lightning attracting device and the wind power generation device of the wind turbine blade according to the fifth embodiment will be described.

In the fifth embodiment shown in FIG. 16, the main difference is that the second conductive band is located at an intermediate position between the metal conductor and the leading edge when viewed from the front of the wind power generation device. The configuration of is substantially the same as that of the first embodiment shown in FIGS. 1 to 7. In FIG. 16, the same parts as those of the first embodiment shown in FIGS. 1 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 16, the second conductive band 32 according to the present embodiment is located at an intermediate position between the metal conducting wire 15 and the leading edge 17 when viewed from the front of the wind power generation device 1. In this case, the distance r ₁ between the second conductive band 32 and the leading edge 17 may be equal to the distance r ₂ between the second conductive band 32 and the metal conducting wire 15.

As described above, according to the present embodiment, the second conductive band 32 is located at an intermediate position between the metal conducting wire 15 and the leading edge 17 when viewed from the front of the wind power generation device 1. As a result, even if a lightning strike streamer extends not only to the leading edge 17 of the wind turbine blade 12 but also to the central region between the leading edge 17 and the trailing edge 18, the lightning strike can be captured by the second conductive band 32. can. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 due to lightning strikes can be suppressed.

Further, according to the present embodiment, it is possible to prevent the second conductive band 32 from approaching the metal conducting wire 15. Therefore, even when a lightning strike occurs on the second conductive band 32, it is possible to prevent the lightning strike current from being arc-discharged from the blade main body 13 and reaching the metal conductor wire 15. As a result, it is possible to prevent the blade body 13 from being damaged due to an increase in the air pressure in the hollow portion 19.

(Sixth Embodiment)
Next, with reference to FIG. 17, the lightning attracting device and the wind power generation device of the wind turbine blade according to the sixth embodiment will be described.

In the sixth embodiment shown in FIG. 17, the first auxiliary conductive band extends from the second conductive band toward the trailing edge of the wind turbine blade, and the third conductive band extends toward the leading edge of the wind turbine blade. The main difference is that the second auxiliary conductive band extends, and the other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 7. In FIG. 17, the same parts as those of the first embodiment shown in FIGS. 1 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 17, the lightning attracting device 30 according to the present embodiment further includes a first auxiliary conductive band 81 and a second auxiliary conductive band 82.

The first auxiliary conductive band 81 extends from the second conductive band 32 toward the trailing edge 18 of the wind turbine blade 12. In the present embodiment, a plurality of first auxiliary conductive bands 81 extend from the second conductive band 32. The plurality of first auxiliary conductive bands 81 are arranged in the longitudinal direction of the blade main body 13, and the first auxiliary conductive bands 81 adjacent to each other are separated from each other.

The tip of the first auxiliary conductive band 81 is located on the side of the leading edge 17 with respect to the metal conducting wire 15 when viewed from the front of the wind power generation device 1. That is, the tip of the first auxiliary conductive band 81 and the metal conducting wire 15 are separated from each other. The first auxiliary conductive band 81 includes a plurality of conductive pieces 40 arranged through a predetermined gap g1 and an insulating layer 41 in the same manner as the second conductive band 32.

The second auxiliary conductive band 82 extends from the third conductive band 33 toward the leading edge 17 of the wind turbine blade 12. In the present embodiment, a plurality of second auxiliary conductive bands 82 extend from the third conductive band 33. The plurality of second auxiliary conductive bands 82 are arranged in the longitudinal direction of the blade main body 13, and the second auxiliary conductive bands 82 adjacent to each other are separated from each other.

The tip of the second auxiliary conductive band 82 is located on the trailing edge 18 side of the metal conductor 15 when viewed from the front of the wind power generation device 1. That is, the tip of the second auxiliary conductive band 82 and the metal conducting wire 15 are separated from each other. The second auxiliary conductive band 82 includes a plurality of conductive pieces 40 arranged through a predetermined gap g1 and an insulating layer 41 in the same manner as the third conductive band 33.

As described above, according to the present embodiment, the first auxiliary conductive band 81 extends from the second conductive band 32 toward the trailing edge 18 of the wind turbine blade 12. As a result, even when a lightning strike streamer extends not only to the leading edge 17 of the wind turbine blade 12 but also to the central region located between the leading edge 17 and the trailing edge 18, the lightning strike is captured by the first auxiliary conductive band 81. can do. In this case, the lightning strike current can be guided from the first auxiliary conductive band 81 to the lightning receiving portion 14 through the second conductive band 32, and can be safely flowed to the ground. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 due to lightning strikes can be suppressed.

Further, according to the present embodiment, the tip of the first auxiliary conductive band 81 is located on the leading edge 17 side of the metal conducting wire 15 when viewed from the front of the wind power generation device 1. As a result, the tip of the first auxiliary conductive band 81 can be kept away from the metal conducting wire 15. Therefore, even when a lightning strike occurs at the tip of the first auxiliary conductive band 81, it is possible to prevent the lightning strike current from being arc-discharged from the blade main body 13 and reaching the metal conductor wire 15. As a result, it is possible to prevent the blade body 13 from being damaged due to an increase in the air pressure in the hollow portion 19.

Further, according to the present embodiment, the second auxiliary conductive band 82 extends from the third conductive band 33 toward the leading edge 17 of the wind turbine blade 12. As a result, even when a lightning strike streamer extends not only to the trailing edge 18 of the wind turbine blade 12 but also to the central region located between the leading edge 17 and the trailing edge 18, the lightning strike is captured by the second auxiliary conductive band 82. can do. In this case, the lightning strike current can be guided from the second auxiliary conductive band 82 to the lightning receiving portion 14 through the third conductive band 33, and can be safely flowed to the ground. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 due to lightning strikes can be suppressed.

Further, according to the present embodiment, the tip of the second auxiliary conductive band 82 is located on the trailing edge 18 side of the metal conductor 15 when viewed from the front of the wind power generation device 1. As a result, the tip of the second auxiliary conductive band 82 can be kept away from the metal conducting wire 15. Therefore, even when a lightning strike occurs at the tip of the second auxiliary conductive band 82, it is possible to prevent the lightning strike current from being arc-discharged from the blade main body 13 and reaching the metal conductor wire 15. As a result, it is possible to prevent the blade body 13 from being damaged due to an increase in the air pressure in the hollow portion 19.

(7th embodiment)
Next, the lightning attracting device and the wind power generation device of the wind turbine blade according to the seventh embodiment will be described with reference to FIGS. 18 and 19.

In the seventh embodiment shown in FIGS. 18 and 19, the first auxiliary conductive band extends from the second conductive band toward the leading edge of the wind turbine blade, and the trailing edge of the wind turbine blade extends from the third conductive band. The main difference is that the second auxiliary conductive band extends toward the direction, and the other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 7. In FIGS. 18 and 19, the same parts as those of the first embodiment shown in FIGS. 1 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 18, the lightning attracting device 30 according to the present embodiment further includes a first auxiliary conductive band 91 and a second auxiliary conductive band 92.

The first auxiliary conductive band 91 extends from the second conductive band 32 toward the leading edge 17 of the wind turbine blade 12. In the present embodiment, a plurality of first auxiliary conductive bands 91 extend from the second conductive band 32. The plurality of first auxiliary conductive bands 91 are arranged in the longitudinal direction of the blade main body 13, and the first auxiliary conductive bands 91 adjacent to each other are separated from each other.

The tip of the first auxiliary conductive band 91 may reach the leading edge 17. The first auxiliary conductive band 91 includes a plurality of conductive pieces 40 arranged through a predetermined gap g1 and an insulating layer 41 in the same manner as the second conductive band 32.

The second auxiliary conductive band 92 extends from the third conductive band 33 toward the trailing edge 18 of the wind turbine blade 12. In the present embodiment, a plurality of second auxiliary conductive bands 92 extend from the third conductive band 33. The plurality of second auxiliary conductive bands 92 are arranged in the longitudinal direction of the blade main body 13, and the second auxiliary conductive bands 92 adjacent to each other are separated from each other.

The tip of the second auxiliary conductive band 92 may reach the trailing edge 18. The second auxiliary conductive band 92 includes a plurality of conductive pieces 40 arranged through a predetermined gap g1 and an insulating layer 41 in the same manner as the third conductive band 33.

In order to avoid a lightning strike on the wind turbine blade 12, it is preferable to land a lightning streamer on the conductive band. In general, thunderclouds are accumulating negative charges. Therefore, the lightning streamer traveling from the thundercloud toward the wind turbine blade 12 is negatively charged. However, thunderclouds that cause great lightning damage to the wind turbine blade 12 are accumulating positive charges. The lightning streamer traveling from this lightning strike toward the wind turbine blade 12 is positively charged. When a positive lightning streamer lands on the blade body 13, the lightning current passes through the blade body 13 and is easily arc-discharged to reach the metal conductor 15.

FIG. 19A shows the state of a lightning strike when the first auxiliary conductive band 91 and the second auxiliary conductive band 92 are not provided. In this case, when the positively charged lightning streamer S1 propagates to the trailing edge 18 of the blade body 13, electrons are emitted from the trailing edge 18 to form a negatively charged precursor discharge S2. The precursor discharge S2 can be generated not only from a metal member such as a conductive band but also from an insulating member. Then, it tends to occur from a portion having a large curvature of the blade main body 13 such as the trailing edge 18.

The positively charged lightning streamer S1 and the negatively charged precursor discharge S2 combine in the atmosphere. As a result, the thundercloud and the wind turbine blade 12 are energized, and a large amount of electric charge and energy are sent from the thundercloud to the wind turbine blade 12. In this way, the wind turbine blade 12 can be damaged by a lightning strike.

FIG. 19B shows the state of a lightning strike when the first auxiliary conductive band 91 and the second auxiliary conductive band 92 are provided. In this case, electrons are emitted from the second auxiliary conductive band 92 in an electric field to form a precursor discharge S2. Therefore, the positively charged lightning streamer S1 and the negatively charged precursor discharge S2 are combined, and the thundercloud and the second auxiliary conductive band 92 are energized. Therefore, it is possible to prevent the blade body 13 from being hit by lightning strikes.

Also at the leading edge 17 of the blade body 13, a negatively charged precursor discharge can be formed with respect to a positively charged lightning streamer. Even in this case, since the first auxiliary conductive band 91 is provided, the thundercloud and the first auxiliary conductive band 91 can be energized, and the blade main body 13 can be suppressed from being hit by lightning strikes.

As described above, according to the present embodiment, the first auxiliary conductive band 91 extends from the second conductive band 32 toward the leading edge 17 of the wind turbine blade 12. As a result, even when the lightning strike streamer advances toward the leading edge 17 of the wind turbine blade 12, the lightning strike can be captured by the first auxiliary conductive band 91. In this case, the lightning strike current can be guided from the first auxiliary conductive band 91 to the lightning receiving portion 14 through the second conductive band 32, and can be safely flowed to the ground. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 due to lightning strikes can be suppressed. In particular, even when a positively charged lightning streamer extends to the leading edge 17, lightning can be applied to the first auxiliary conductive band 91, and damage to the wind turbine blade 12 can be suppressed.

Further, according to the present embodiment, the second auxiliary conductive band 92 extends from the third conductive band 33 toward the trailing edge 18 of the wind turbine blade 12. As a result, even when the lightning strike streamer advances toward the trailing edge 18 of the wind turbine blade 12, the lightning strike can be captured by the second auxiliary conductive band 92. In this case, the lightning strike current can be guided from the second auxiliary conductive band 92 to the lightning receiving portion 14 through the third conductive band 33, and can be safely flowed to the ground. Therefore, the capture rate of lightning strikes can be improved, and damage to the wind turbine blade 12 due to lightning strikes can be suppressed. In particular, even when a positively charged lightning streamer extends to the trailing edge 18, lightning can be applied to the second auxiliary conductive band 92, and damage to the wind turbine blade 12 can be suppressed.

According to the above-described embodiment, the lightning strike capture rate can be improved, and damage to the wind turbine blade due to a lightning strike can be suppressed.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof. Further, as a matter of course, it is also possible to appropriately combine these embodiments within the scope of the gist of the present invention.

1: Wind power generator, 12: Windmill blade, 13a: Pressure surface, 13b: Negative pressure surface, 13t: Tip, 14: Lightning receiving part, 15: Metal conductor, 16: Drain hole, 17: Front edge, 18: Rear Edge, 19: Hollow part, 30: Lightning attracting device, 31: 1st conductive band, 32: 2nd conductive band, 33: 3rd conductive band, 40: Conductive piece, 50: Filling part, 51: Front edge of filling part , 60: Dissimilar material boundary, 61: 1st material part, 62: 2nd material part, 64: Structural material thickness boundary, 70: 4th conductive band, 81: 1st auxiliary conductive band, 82: 2nd auxiliary conductive band , 91: 1st auxiliary conductive band, 92: 2nd auxiliary conductive band

Claims (14)

Installed on a wind turbine blade of a wind power generator, including a lightning strike, a metal lead wire that electrically grounds the lightning strike, and a drain hole provided at the tip of the lightning strike. It is a lightning attracting device for wind turbine blades that induces a lightning current to the lightning receiving part.
A first conductive band provided on at least one of the pressure surface and the negative pressure surface of the wind turbine blade and forming an induction path for the lightning current is provided.
The first conductive band is a lightning attracting device for a wind turbine blade extending from the lightning receiving portion side toward the drain hole. The lightning attracting device for a wind turbine blade according to claim 1, wherein the tip of the first conductive band is located closer to the lightning receiving portion than the drain hole. The lightning attracting device for a wind turbine blade according to claim 1, wherein the first conductive band includes a plurality of conductive pieces arranged through a gap in the extending direction of the first conductive band. A second conductive band and a third conductive band provided on the pressure surface and the negative pressure surface of the wind turbine blade provided with the first conductive band and forming an induction path for the lightning current are further provided.
The second conductive band extends from the lightning receiving portion side so as to be on the side opposite to the tip of the wind turbine blade from the lightning receiving portion and along the leading edge of the wind turbine blade.
Any of claims 1 to 3, wherein the third conductive band extends from the lightning receiving portion side of the lightning receiving portion on the side opposite to the tip of the wind turbine blade and along the trailing edge of the wind turbine blade. The lightning attracting device for the wind turbine blade described in item 1. A filling portion is provided in a portion of the hollow portion of the wind turbine blade on the side of the trailing edge of the wind turbine blade.
The filling portion includes a filling portion leading edge located on the side of the leading edge of the wind turbine blade.
The lightning attracting device for a wind turbine blade according to claim 4, wherein the third conductive band is located along the leading edge of the filling portion. The wind turbine blade comprises a dissimilar material boundary that separates two portions formed of different structural materials from each other.
The lightning attracting device for a wind turbine blade according to claim 4, wherein the third conductive band is located along the boundary between different materials. The wind turbine blade includes a structural material thickness boundary in which the thickness of the structural material constituting the wind turbine blade changes.
The lightning attracting device for a wind turbine blade according to claim 4, wherein the third conductive band is located along the structural material thickness boundary. A fourth conductive band provided on the pressure surface and the negative pressure surface of the wind turbine blade provided with the third conductive band and forming an induction path for the lightning current is further provided.
The fourth conductive band is located on the side opposite to the tip of the wind turbine blade from the lightning receiving portion and between the metal conducting wire and the third conductive band when viewed from the front of the wind power generator. , The lightning attracting device for a wind turbine blade according to any one of claims 4 to 7. The second conductive band according to any one of claims 4 to 8, wherein the second conductive band is located at an intermediate position between the metal conducting wire and the leading edge of the wind turbine blade when viewed from the front of the wind power generation device. Wind turbine blade lightning attractor. A first auxiliary conductive band extending from the second conductive band toward the trailing edge of the wind turbine blade is further provided.
One of claims 4 to 9, wherein the tip of the first auxiliary conductive band is located closer to the front edge of the wind turbine blade than the metal lead wire when viewed from the front of the wind power generation device. The wind turbine blade lightning attracting device described in. Further provided with a second auxiliary conductive band extending from the third conductive band toward the leading edge of the wind turbine blade.
One of claims 4 to 10, wherein the tip of the second auxiliary conductive band is located closer to the trailing edge of the wind turbine blade than the metal lead wire when viewed from the front of the wind power generation device. The wind turbine blade lightning attracting device described in. The lightning attracting device for a wind turbine blade according to any one of claims 4 to 9, further comprising a first auxiliary conductive band extending from the second conductive band toward the leading edge of the wind turbine blade. The lightning attracting device for a wind turbine blade according to any one of claims 4 to 9 and 12, further comprising a second auxiliary conductive band extending from the third conductive band toward the trailing edge of the wind turbine blade. A plurality of wind turbine blades including a lightning receiving portion, a metal lead wire for electrically grounding the lightning receiving portion, and a drain hole provided on the tip side of the lightning receiving portion.
The lightning attracting device for a wind turbine blade according to any one of claims 1 to 13 installed on the wind turbine blade, comprising a lightning attracting device for the wind turbine blade that induces a lightning current to the light receiving portion. Also, a wind power generator.

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