JP7391304B2 - Wind turbine lightning protection device - Google Patents

Description

Article 30, Paragraph 2 of the Patent Act applies Publisher: The Institute of Electrical Engineers of Japan, Yuyuki Sakai Publications: IEEJ study group materials High Voltage Study Group Publication date: January 24, 2019 [Publications] Meeting name: High Voltage Study Group Venue Hiratoku Community Center Dates: January 24, 2019 - January 25, 2019

The present invention relates to a lightning protection device for a wind turbine.

a receptor provided with at least a portion exposed on the surface of a blade of a wind turbine; a guide portion that guides lightning current generated at at least a portion of the surface of the blade other than the receptor to the receptor; A lightning protection device for a wind turbine is known, which includes a down conductor that is electrically connected to a receptor and guides lightning current from the receptor side to the ground side, and the guide portion includes a plurality of conductive members having conductivity. (For example, see Patent Document 1.).

The lightning protection device for wind turbines described in the above-mentioned document is capable of guiding this lightning current to the receptor side by the guide portion even if lightning strikes at least a part of the surface of the blade other than the receptor and a lightning current is generated. This makes it possible to suppress damage to the blade due to lightning strikes.

On the other hand, heat generated during lightning strikes can cause electrically conductive members to break or disappear. If the function of the guide portion is reduced or malfunctions due to damage or disappearance of the conductive member, the original purpose of preventing damage to the blade cannot be achieved.

Japanese Patent Application Publication No. 2007-100658

SUMMARY OF THE INVENTION An object of the present invention is to provide a lightning arrester for a wind turbine that can stably and long-term prevent damage to blades due to sufficient heat resistance of a conductive member.

In order to solve the above problems, a lightning protection device for a wind turbine is provided, which includes a receptor provided with at least a portion exposed on the surface of the blade of the wind turbine, and a receptor provided in at least a portion of the surface of the blade other than the receptor. A guide part that guides the generated lightning current to the receptor, and a down conductor that is electrically connected to the receptor and guides the lightning current from the receptor side to the ground side, and the guide part has electrical conductivity. The plurality of conductive members are arranged in a linear or curved manner toward the receptor, and the conductive member is made of at least one of molybdenum, tungsten, hafnium, tantalum, chromium, or niobium. The conductive member is formed into a rectangular plate shape and fixed to the blade side in a posture along the surface of the blade, and the conductive member is parallel or substantially parallel to each other. The distance between adjacent end faces facing each other is set to 2 mm or less, and the end faces of the conductive member are formed into a flat shape, and the area thereof is set to 3 mm 2 or more ^.

The guide portion includes an insulating member extending in a band shape in the guide direction, at least a portion of the conductive member is embedded and fixed in the insulating member, and the insulating member is attached to the surface of the blade. It may also be attached to the side.

The area of the end surface of the conductive member may be set to 5 mm ² or more.

The conductive member may include the heat-resistant material and a non-heat-resistant material that is a material other than the heat-resistant material, or may be composed only of one or more of the heat-resistant materials.

The conductive member may have a volume resistivity of 20 μΩcm or less at 20° C.

The heat-resistant material may be molybdenum, the non-heat-resistant material may be copper, and the weight ratio of the molybdenum to the entire conductive member may be set to 10% or more.

The conductive member may be made of only the heat-resistant material.

Since the conductive member containing the heat-resistant material has high heat resistance, damage to the blade can be prevented stably and over a long period of time.

FIG. 1 is a front view of a wind turbine equipped with a lightning protection device to which the present invention is applied. FIG. 3 is an enlarged front view of the main part of the blade. 3 is a sectional view taken along line AA in FIG. 2. FIG. It is a front view of a guide part. 5 is a sectional view taken along line BB′ in FIG. 4. FIG. FIG. 7 is a cross-sectional view showing the configuration of another embodiment of the guide portion. This is a discharge waveform that mimics lightning. It is a graph showing melting loss during two types of electric discharges simulating lightning. It is a photograph showing the state of each guide part after discharge when a discharge consisting of waveform B of charge 60C is generated, and (A) is the state of the guide part using a conductive plate made of molybdenum to which the present invention is applied. (B) is the state of the guide part using a conductive plate made of a composite material to which the present invention is applied, (C) is the state of the guide part using a comparison plate made of aluminum, and (D) is the state of the guide part using a comparative plate made of aluminum. This is the state of the guide section using a comparison plate made of copper. It is a photograph showing the state of each guide part after discharge when a discharge consisting of waveform B of charge 180C is generated, and (A) is the state of the guide part using a conductive plate made of molybdenum to which the present invention is applied. (B) is the state of the guide part using a conductive plate made of a composite material to which the present invention is applied, (C) is the state of the guide part using a comparison plate made of aluminum, and (D) is the state of the guide part using a comparative plate made of aluminum. This is the state of the guide section using a comparison plate made of copper.

FIG. 1 is a front view of a wind turbine equipped with a lightning protection device to which the present invention is applied, FIG. 2 is an enlarged front view of the main part of the blade, and FIG. 3 is a sectional view taken along line AA' in FIG. The windmill shown in the figure is used as a wind power generation device. This wind turbine includes a tower 2 that protrudes directly above a foundation 1 on the ground and has a cavity inside, a nacelle 3 that is installed at the upper end of the tower 2 and is formed horizontally, and a longitudinal direction of the nacelle 3. A plurality of blades 4 are arranged on one end side of the blade. Incidentally, for convenience, the direction in which the nacelle 3 is formed is defined as the front-rear direction, and the side of the nacelle 3 provided with the blade is defined as the front side.

The plurality of blades 4 are rotated as a whole by a hub (not shown), which is a rotating shaft (not shown), which is disposed at the center of the nacelle 3 when viewed in the longitudinal direction and is formed in the direction of the nacelle 3. It is supported by nacelle 3. The plurality of blades 4 are formed to protrude radially from the hub when viewed in the axial direction of the hub, and are arranged at predetermined intervals in the direction around the axis of the hub. Each blade 4 is made of a strong and lightweight insulating material such as FRP. A cavity 4a is formed inside each blade 4.

The blade 4 and the cavity 4a are shaped like a convex lens when viewed in cross section along the entire length of the blade 4. The cavity 4a is formed over the entire or substantially entire length of the blade 4. Further, the blade 4 has a curved surface whose front and rear outer surfaces bulge outward.

When the plurality of blades 4 receive wind, they rotate together with the hub as a whole, and this rotational power causes a generator (not shown) installed inside the nacelle 3 to generate electricity. The generated power is supplied to power transmission lines and batteries (not shown).

By the way, in order to increase the efficiency of wind power generation, it is necessary for the blades 4 to receive strong winds without being affected by the surroundings, so it is desirable to install the blades 4 at a high place. However, at high places, the possibility of lightning strikes increases, and the risk of damage to the blade 4 due to lightning strikes increases. In order to cope with such lightning strikes, this wind turbine is equipped with a lightning protection device.

The lightning protection device includes a receptor 6 installed on the front and rear outer surfaces (surfaces) of the tip, which is the end far from the hub in the overall length direction of each blade 4, and a down conductor (down conductor) that connects the receptor 6 to ground. 7, a fixing block 8 that is arranged near the tip of the cavity 4a of the blade 4 and fixes the receptor 6, and a lightning strike that occurs at a part of the surface of the blade 4 other than the receptor 6 due to a lightning strike or the like. It has a guide portion 9 that guides the current to the receptor 4 side (forms a conduction path for lightning current).

The outer receptor 6 and the inner fixing block 8 are removably fastened together to the blade 4 by bolts 11 passing through the inside and outside of the blade 4. Since the fixed block 8 and the bolt 11 are made of a metal material, which is a type of conductive material, they are electrically connected to the receptor 6, and the fixed block 8 is grounded (earthed) by the down conductor 7. With the above configuration, the receptor 6 is grounded, and it becomes possible to release the lightning current generated during a lightning strike into the ground. Incidentally, the fixed block 8 is bolted to the blade 4 from both the front and rear outer surfaces.

According to this configuration, not only when lightning strikes the receptor 6 of the blade 4 or its vicinity, but also when lightning strikes a location other than the receptor 6 of the blade 4, the lightning current generated at that time is transferred from the receptor 6 to the down conductor. It becomes possible to escape through 7. Therefore, damage to the blade 4 due to lightning can be efficiently prevented.

Next, the configuration of the guide portion 9 will be explained based on FIGS. 2, 4, and 5.

FIG. 4 is a front view of the guide part, and FIG. 5 is a sectional view taken along line BB' in FIG. The guide portion 9 is arranged linearly or curvedly (in the illustrated example, linearly) at predetermined intervals or continuously (at predetermined intervals in the illustrated example) in the guide direction, which is a direction from a predetermined position of the blade 4 toward the receptor 4. ) and have a plurality of conductive plates (conductive members) 12 having conductivity, and an insulating tape (insulating member) 13 formed in a band shape over the entire guide direction.

In the illustrated example, the guide direction is directed in the overall length direction of the blade 4. When viewed in the axial direction of the hub, the guide portion 9 is provided in a range that is a predetermined distance away from the vicinity of the receptor 6 at the tip of the blade 4 toward the hub.

Each conductive plate 12 has a slightly elongated rectangular shape in the above-mentioned guide direction, and has an isosceles trapezoid shape when viewed in the guide direction. The conductive plate 12 is made of only a heat-resistant material containing at least one of molybdenum, tungsten, hafnium, tantalum, chromium, or niobium, or a heat-resistant material and a non-heat-resistant material other than the heat-resistant material. It has at least the following.

In this example, the conductive plate 12 is made of molybdenum, which is a heat-resistant material, and copper, which is a non-heat-resistant material. The weight ratio of copper to the entire conductive plate 12 is set higher than that of molybdenum. The specific weight ratio of molybdenum to the entire conductive plate 12 is set to 10% or more, more preferably 20% or more.

Incidentally, in the conductive plate 12, it is necessary to make each of molybdenum and copper as uniform as possible. However, when the conductive plate 12 is manufactured by melting molybdenum and copper, segregation occurs due to the difference in melting point of each material. In order to prevent such material deviation, the conductive plate 12 is manufactured by a spark plasma sintering (SPS) method in which powdered copper and molybdenum are sintered by mechanical pressure and pulsed current heating. There is.

By using the conductive plate 12 manufactured in this way, it becomes possible to easily manufacture the guide portion 9 which is provided with high heat resistance at a low cost. This heat resistance makes it possible to prevent damage to the guide portion 9 (specifically, melting or disappearance of the conductive plate 12) due to heat generated during a lightning strike, and to maintain its function for a long period of time.

Further, the end surfaces of the adjacent conductive plates 12, 12 become opposing surfaces 12a, 12a that are close to each other and face parallel or substantially parallel to each other, respectively. This opposing surface 12a is a flat surface that forms an isosceles trapezoid shape due to the shape of the conductive plate 12 described above. Due to the shape of the conductive plate 12, corners are formed at the connecting portions between the facing surface 12a and the flat front and back surfaces of the conductive plate 12, and at the connecting portions between the facing surface 12a and both side surfaces of the conductive plate 12. It is formed.

The inclination angles of the side surfaces on both sides of the conductive plate 12 can be set as appropriate with respect to the front and back surfaces of the conductive plate 12. On the other hand, the opposing area, which is the area of the opposing surface 12a of the conductive plate 12, and the cross-sectional area, which is the area of the cross section in the overall length direction, are related to melting of the conductive plate 12, and therefore need to be appropriately set. Incidentally, the opposing area and the cross-sectional area are the same in this example.

First, the calorific value Q of the conductive plate 12 is calculated by the following formula.

In this calculation formula, I is the current, R is the resistance, t is the time, ρ _e is the volume resistivity of the material constituting the conductive plate 12, L is the total length of the conductive plate 12, and S is the cross-sectional area of the conductive plate 12. .

Further, the heat capacity C of the conductive plate 12 is calculated by the following formula.

In this calculation formula, C _p is the specific heat of the material constituting the conductive plate 12 , ρ _m is the density of the material constituting the conductive plate 12 , and V is the volume of the conductive plate 12 .

Then, the temperature rise ΔT of the conductive plate 12 is calculated by the following formula.

In the case of winter lightning, which tends to have higher energy than in summer, a current of 100 [kA] flows for 1 [ms]. Here, for example, when molybdenum whose melting point is 2600 [°C] is included in the conductive plate 12, its volume resistivity (ρ _e ) at room temperature (specifically, 20 [°C]) is 5.34 [μΩcm]. , specific heat (C _p ) is 0.25 [J/gK], and density (ρ _m ) is 10.2 [g/cm ³ ]. When all the generated heat contributes to the temperature, the cross-sectional area of the conductive plate 12 needs to be set to 3 [mm ² ] or more, preferably 5 [mm ² ] or more, more preferably 10 [mm ² ]. The above is desirable.

Note that the widthwise dimension of the conductive plate 12 is set to 5 [mm] or more, and the overall length dimension is set in the range of 5 to 100 [mm] to facilitate handling.

Further, the distance between the facing surfaces 12a, 12a of the adjacent conductive plates 12, 12 is desirably set to 2 [mm] or less in order to facilitate the generation of discharge.

As described above, each conductive plate 12 has its entire length directed toward the guide direction (in other words, its width direction is directed perpendicular to the guide direction), and the longer width of both its front and back surfaces. is the fixed surface 12b which is the surface near the surface of the blade 4, and the other side with the shorter width is the lightning receiving surface 12c which is the surface far from the surface of the blade 4. , is fixed to the blade 4 via an insulating member 13. As a result, the conductive plate 12 is fixed to the surface side of the blade 4 with the entire conductive plate 12 aligned along the surface of the blade 4.

The material constituting the insulating tape 13 may be any material that satisfies the above requirements, taking into consideration flexibility, weather resistance, adhesion to the blade 4, etc. For example, epoxy resin, silicone, etc. Elastically deformable synthetic resin such as resin may be selected as the material for the insulating tape 13.

Further, the insulating tape 13 has a recess 13a that is provided for each of the plurality of conductive plates 12 and that locks and accommodates the conductive plate 12. This recess 13a is formed into a dovetail groove shape when viewed in cross section in the guide direction, and the conductive plate 12 is buried therein with its lightning receiving surface 12c exposed to the outside. Incidentally, the thickness of the insulating tape 13 is set to 5 [mm] or less.

To briefly explain the method for manufacturing the guide portion 9, a plurality of conductive plates 12 are arranged in parallel inside a mold, and then the material constituting the insulating member 13 is introduced in a fluid state into the mold. The guide portion 9 is integrally formed by cooling or drying it into a solid state.

By the way, this conductive plate 12 is difficult to adhere directly to the surface of the blade 4 due to its constituent material, and if a plurality of conductive plates 12 are arranged in parallel and installed individually on the surface side of the blade 4, it takes much time and effort. However, the above-described configuration of the guide section 9 solves these problems.

That is, the recess 13a having a dovetail cross-sectional shape accommodates substantially all of the conductive plate 12 having the same or substantially the same cross-sectional shape as the recess 13a, thereby reliably fixing the conductive plate 12 to the insulating tape 13, and further insulating the conductive plate 12. By adhering and fixing the tape 13 to the surface of the blade with an adhesive, double-sided tape, etc., it becomes possible to collectively fix the plurality of conductive plates 12 arranged in parallel to the surface side of the blade 4. .

According to the guide portion 9 configured as described above, sufficient heat resistance can be achieved by making use of specific properties of molybdenum, which is an expensive heat-resistant material, and by containing a large amount of copper, which is an inexpensive non-heat-resistant material. Since the provided conductive plate 12 can be made inexpensive, damage caused by heat generated during a lightning strike can be prevented as much as possible. Furthermore, the elastically deformable insulating tape 13 allows it to be easily and quickly installed even on the outer surface of the blade 4 having a convex curved surface.

Note that the lightning receiving surface 12c of the conductive plate 12 is not necessarily exposed from the band-shaped insulating material 13, and may be partially or entirely covered by the insulating material 13.

Alternatively, the guide portion 9 may be configured only of a plurality of conductive plates 12, and the conductive plates 12 may be directly attached and fixed to the blade 4 using an adhesive or the like.

Furthermore, ceramics, tungsten, or graphite may be used as the heat-resistant material of the conductive plate 12, and a general-purpose metal material such as copper may be used as the non-heat-resistant material. Further, the conductive plate 12 may be made of tungsten, which is a heat-resistant material, and thorium oxide.

Next, another embodiment of the guide section 9 will be described based on FIG. 6.

FIG. 6 is a sectional view showing the configuration of another embodiment of the guide section. In this embodiment, the shapes of the conductive plate 12 and the recess 13a in the cross-sectional view in the guide direction are formed to be the same or substantially the same as in the above-mentioned embodiment, but the shape is not a trapezoid but a rectangle. It is molded into Further, the width of the side of the strip-shaped insulating material 13 that is bonded to the blade 4 may be set larger than that of the opposite side.

Incidentally, it is possible to select various shapes as appropriate without being limited to the shapes shown in FIGS. 5 and 6.

Next, the results of experiments conducted on the conductive plate 12 using the guide portion 9 to which the present invention is applied will be explained.

Three types of composite materials of copper and molybdenum constituting the conductive plate 12 were prepared. Specifically, there is a "Cu-10Mo composite" in which the weight ratio of copper to the whole is 90% and the weight ratio of molybdenum to the whole is 10%, and a "Cu-10Mo composite material" in which the weight ratio of copper to the whole is 80%. "Cu-20Mo composite material" in which the weight ratio of molybdenum to the whole is 20%, and the "Cu-20Mo composite material" in which the weight ratio of copper to the whole is 70% and the weight ratio to the whole molybdenum is 30%. A total of three types of composite materials were prepared, including a certain "Cu-30Mo composite material."

The conductive plate 12 was formed into a disk shape in consideration of ease of experimentation.

On the other hand, for comparison with the conductive plate 12 made of these three types of composite materials, a comparison plate made only of copper and molded to the same size and shape as the conductive plate 12 was prepared.

Briefly explaining the method for manufacturing the three types of composite materials mentioned above, first, powdered copper and molybdenum are mixed in the above-mentioned predetermined ratio to obtain a mixed powder. This mixed powder was added to an alcohol solution poured into a polyethylene pot along with a stainless steel ball with a diameter (φ) of 10 [mm], and after performing ball milling for several hours, the balls were removed and dried. By doing so, a dry powder, which is a mixed powder with a reduced particle size, is obtained.

This dry powder is filled into a graphite die having a movable punch with an inner diameter of 102 [mm], and in an atmosphere having a vacuum of 10 [Pa] or less or a low pressure close to vacuum and a temperature of 1173 [K] or more. It is held for 1200 seconds or more by uniaxial pressure of 50 [MPa] and fired by the SUS method to obtain the three types of composite materials described above.

FIG. 7 shows waveforms of two types of discharges simulating lightning. Waveform A, indicated by "Wave form A" in the figure, simulates summer lightning, and waveform B, indicated by "Wave form B" in the same figure, simulates winter lightning; is compliant with the "JIS Z 9290-1" standard.

The three types of conductive plates 12 and the comparison plate are bolted to the ground-connected down conductor, and electrodes made of stainless steel round rods with a diameter of 12 mm are attached to the disc-shaped edges of the three types of conductive plates 12 and the comparison plate. They were brought close to each other and discharged according to waveforms A and B, respectively, and the melting damage was confirmed.

FIG. 8 is a graph showing melting loss during two types of electric discharges simulating lightning. By the way, what is shown in the same figure was obtained by calculating the melting loss when the specific energy was 1680 [MWΩ ^-1 ] from the results of the experiment. This allows for comparison between samples.

In the discharge using waveform A that simulates summer lightning, a significant difference was observed between the comparison plate and the three types of conductive plates 12 in terms of erosion, and as the molybdenum content increased, the erosion increased. You can check the suppressed state. That is, it was confirmed that a sufficient effect can be expected if the weight ratio of molybdenum to the whole is set to 10% or more.

On the other hand, in the discharge using waveform B that simulates winter lightning, the comparison plate and the conductive plate 12 of the "Cu-10Mo composite material" and the conductive plate 12 of the "Cu-20Mo composite material" and the "Cu-30Mo composite material" were A significant difference with respect to the conductive plate 12 was observed, and it was also confirmed that as the content of molybdenum increased, the melting loss was suppressed. In other words, it has been confirmed that if the weight ratio of molybdenum to the whole is set to 20% or more, a sufficient effect can be expected even against high-energy winter lightning.

Next, the results of experiments conducted on the guide section 9 to which the present invention is applied will be explained.

As the conductive plate 12, a material of "Cu-30Mo composite material" is used, its thickness is set to 1.5 [mm], its width is set to 10 [mm], and its total length is set to 30.50 [mm]. Two patterns were prepared, and the inclination angles of the side surfaces on both sides were set to 45 degrees. Further, a conductive plate made of only molybdenum, which is a heat-resistant material, and molded to have the same or substantially the same dimensions and shape as the conductive plate 12 was also prepared. On the other hand, two types of comparison plates were prepared, one made only of copper and one made only of aluminum, and molded into the same or substantially the same size and shape as the conductive plate 12.

The insulating tape 13 having a concave portion 13a in which these two types of conductive plates 12 or two types of comparison plates are embedded is made of silicone resin, has a total length of 900 mm, and a thickness of 2 mm. 0 [mm], and the interval between adjacent recesses 13a was set to 1 [mm].

The discharge to be used simulated winter lightning having the waveform B described above, and the experiment was conducted in two patterns: when the charge was 60 [C] and when the charge was 180 [C]. The location where the discharge was generated was near the center of both the guide section 9 using the conductive plate and the three guide sections using the comparison plates.

FIG. 9 is a photograph showing the state of each guide portion after discharge when a discharge consisting of waveform B of charge 60C is generated, and (A) is a guide using a conductive plate made of molybdenum to which the present invention is applied. (B) is the state of the guide part using a conductive plate made of a composite material to which the present invention is applied, (C) is the state of the guide part using a comparison plate made of aluminum, (D) shows the state of the guide section using a comparison plate made of copper.

In the same figure (A), the total length of the area that evaporated and disappeared was 1.9 [mm], and the total length of the area that was eroded was 6.8 [mm]. In the same figure (B), the total length of the area that evaporated and disappeared was 1.9 [mm], and the total length of the area that was eroded was 11.9 [mm]. In the same figure (C), the total length of the area that evaporated and disappeared was 9.1 [mm], and the total length of the area that was eroded was 16.9 [mm]. In the same figure (D), the total length of the area that evaporated and disappeared was 2.9 [mm], and the total length of the area that was eroded was 10.2 [mm].

In contrast to the results shown in Figure (A), in which only molybdenum was used for the conductive plate 12, the disappearance range in Figure (B), in which the composite material was used, was the same; The results showed superior heat resistance compared to D).

FIG. 10 is a photograph showing the state of each guide portion after discharge when a discharge consisting of waveform B of charge 180C is generated, and (A) is a guide using a conductive plate made of molybdenum to which the present invention is applied. (B) is the state of the guide part using a conductive plate made of a composite material to which the present invention is applied, (C) is the state of the guide part using a comparison plate made of aluminum, (D) shows the state of the guide section using a comparison plate made of copper.

In the same figure (A), the total length of the area that evaporated and disappeared was 3.3 [mm], and the total length of the area that was eroded was 14.6 [mm]. In the same figure (B), the total length of the area that evaporated and disappeared was 5.8 [mm], and the total length of the area that was eroded was 23.5 [mm]. In the same figure (C), the total length of the area that evaporated and disappeared was 25.2 [mm], and the total length of the area that was eroded was 40.0 [mm]. In the same figure (D), the total length of the area that evaporated and disappeared was 16.0 [mm], and the total length of the area that was eroded was 25.4 [mm].

In contrast to the results shown in Figure (A) in which only molybdenum was used for the conductive plate 12, the results shown in Figure (B) in which the above-mentioned composite material was used were inferior in the range of disappearance and melting damage, but the results were similar to aluminum and When compared with the results shown in Figures (C) and (D) using copper, the difference was clear, and the results showed excellent heat resistance.

That is, as the electric charge was increased, the guide portion 9 of the present invention exhibited superior heat resistance.

4 Blade 6 Receptor 7 Down conductor 9 Guide portion 12 Conductive plate (conductive member)
13 Insulating tape (insulating material)

Claims (7)

A wind turbine lightning protection device,
a receptor provided on the surface of a windmill blade with at least a portion exposed;
a guide portion that guides lightning current generated at at least a portion of the surface of the blade other than the receptor to the receptor;
a down conductor electrically connected to the receptor and guiding lightning current from the receptor side to the ground side,
The guide portion has a plurality of conductive members having conductivity,
The plurality of conductive members are arranged in a straight line or a curved line toward the receptor side,
The conductive member includes a heat-resistant material containing at least one of molybdenum, tungsten, hafnium, tantalum, chromium, or niobium,
The conductive member is formed into a rectangular plate shape and is fixed to the blade side in a posture along the surface of the blade,
The distance between adjacent end surfaces of the conductive member facing each other parallel or substantially parallel is set to 2 mm or less,
The end surface of the conductive member is formed into a flat shape and has an area of 3 mm ² or more.
A wind turbine lightning protection device characterized by: The guide portion includes an insulating member extending in a band shape in a direction in which the receptors are arranged,
At least a portion of the conductive member is embedded and fixed in the insulating member,
The lightning protection device for a wind turbine according to claim 1 , wherein the insulating member is attached to the front surface side of the blade. The lightning protection device for a wind turbine according to claim 1, wherein the area of the end face of the conductive member is set to 5 mm ² or more. Claims 1 to 3, wherein the conductive member includes the heat-resistant material and a non-heat-resistant material that is a material other than the heat-resistant material, or is composed only of one or more of the heat-resistant materials. A lightning protection device for a wind turbine according to any of the above. The lightning protection device for a wind turbine according to claim 3 , wherein the conductive member has a volume resistivity of 20 μΩcm or less at 20° C. the heat resistant material is molybdenum;
the non-heat resistant material is copper;
The lightning protection device for a wind turbine according to claim 4, wherein a weight ratio of the molybdenum to the entire conductive member is set to 10% or more. The conductive member is composed only of the heat-resistant material,
A lightning protection device for a wind turbine according to any of claims 4 or 5 , wherein the heat-resistant material is molybdenum.

Images