JP2020041432A - Blade and wind power generation device - Google Patents

Abstract

To provide a blade and a wind power generation device that can restrain lightning stroke damage to a blade body.SOLUTION: A blade 1 comprises a blade body, at least one receptor 6 attached to a tip part of the blade body or the vicinity of the tip part, and a down conductor 7 electrically connected to the receptor 6 and installed inside the blade body. An outer surface or an inner surface of the blade body comprises a non-linear resistance material layer 8. The non-linear resistance material layer 8 has a low electric resistance value and becomes conductive when an electric field equal to or higher than a predetermined electric field value is applied, and has a high electric resistance value and becomes resistive when an electric field lower than the predetermined electric field value is applied.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a wind turbine blade and a wind power generator, and more particularly to a wind turbine blade and a wind power generator in consideration of lightning resistance.

  With the increase in size of wind power generators, lightning strike damage to wind power generators has frequently occurred. In particular, there have been many reports of lightning strikes on blades passing the highest point, and countermeasures are needed. Techniques described in the following patent documents have been proposed as techniques relating to lightning strike countermeasures for blades. In Patent Literature 1, a receptor is installed at or near the tip of the blade body, and a down conductor connected to this receptor is wired inside the blade body, thereby effectively preventing lightning damage to the blade body. The techniques obtained are disclosed. Further, Patent Document 2 discloses that a conductive material is coated on at least the surface side of the blade main body only around a boundary between the receptor and the blade main body surface, thereby forming a boundary between the receptor and the blade main body surface and a receptor anchor. A technique that can suppress lightning strikes on the sky is described. Furthermore, in Patent Document 3, a metal material layer and a non-linear resistance material layer are alternately formed on the surface of the blade body while partially contacting each other, and the metal material layer is arranged at the tip of the blade body. There is disclosed a technique capable of preventing damage to a blade main body due to a lightning current by arranging a non-linear resistance material layer in a portion adjacent to a hub of the blade main body.

JP 2005-113735 A JP 2012-246812 A JP 2014-25428 A

A. Candela et. al. , "Lightning Damage to Wind Turbine Blades From Wind Farms in the US," in IEEE Transactions on Power Delivery, vol. 31, no. 3, pp. 1043-1049, June 2016.

In the method described in Patent Literature 1, an electric field is concentrated on the end of the receptor or the receptor anchor, which causes lightning to strike a portion other than the receptor. According to the technique described in Patent Literature 2, an effect of alleviating the electric field concentrated at the end of the receptor or the receptor anchor is expected, but nevertheless, the lightning strike on the blade body continues. On the other hand, in the technique described in Patent Literature 3, when a lightning strike involving a high peak current or a large charge amount occurs a plurality of times, the metal material layer and the nonlinear resistance material layer coated on the surface of the blade body may be burned out. There is. As described above, the techniques described in Patent Literatures 1 to 3 have not yet realized effective lightning strike countermeasures for blades used in wind power generators.
Therefore, an object of the present invention is to provide a blade and a wind power generator capable of suppressing lightning damage to the blade body.

  In order to solve the above-mentioned problem, a blade according to the present invention includes a blade body, at least one receptor attached to a tip portion or near a tip portion of the blade body, and the blade is electrically connected to the receptor. A blade having a down conductor installed inside the main body, having a non-linear resistance material layer on an outer surface or an inner surface of the blade main body, wherein the non-linear resistance material layer has an electric field of a predetermined electric field value or more. When the electric field is applied, the electric resistance is low and the electric field becomes conductive. When an electric field lower than the predetermined electric field is applied, the electric resistance is high and the electric field becomes resistive.

  Further, a wind power generator according to the present invention is a wind power generator having at least a rotor having blades that rotate by receiving wind, and a nacelle that houses a generator that generates electric power by using the rotational energy of the rotor. The blade comprises a blade body, at least one receptor attached at or near the tip of the blade body, and a down conductor electrically connected to the receptor and installed inside the blade body. Having a non-linear resistance material layer on the outer surface or the inner surface of the blade body, the non-linear resistance material layer has a low electric resistance value when an electric field of a predetermined electric field value or more acts, and becomes conductive, When an electric field lower than the predetermined electric field value acts, the electric resistance value is high and the electric resistance is high.

ADVANTAGE OF THE INVENTION According to this invention, the blade and the wind power generator which can suppress the lightning damage of a blade main body can be provided.
Problems, configurations, and effects other than those described above will be apparent from the following description of the embodiments.

1 is an overall schematic configuration diagram of a blade and a wind turbine generator according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating one blade constituting the blade illustrated in FIG. 1. FIG. 3 is a cross-sectional view of a distal end portion of the blade shown in FIG. 2 along a longitudinal direction, and is a view of the blade shown in FIG. FIG. 3 is a cross-sectional view of a distal end portion of the blade shown in FIG. 2 along a longitudinal direction, and is a view of the blade shown in FIG. 2 viewed from a lateral direction, and is a diagram illustrating a principle of lightning strike on a blade main body. FIG. 3 is a view of a blade along the longitudinal direction of the first embodiment viewed from above. FIG. 4 is a diagram illustrating a relationship between the resistivity of a nonlinear resistance material layer and an electric field. FIG. 6 is a cross-sectional view of a tip portion along a longitudinal direction of the blade illustrated in FIG. 5, and is a diagram of the blade illustrated in FIG. 5 when viewed from a lateral direction. It is sectional drawing of the front-end | tip part along the longitudinal direction of Example 2 which concerns on another Example of this invention, and is the figure which looked at the blade from the lateral direction. It is the figure which looked at the tip part along the longitudinal direction of the blade of Example 3 concerning other examples of the present invention from the upper part. FIG. 10 is a diagram illustrating a first modification of the blade illustrated in FIG. 9. FIG. 10 is a diagram illustrating a second modification of the blade illustrated in FIG. 9. It is the figure which looked at the tip part along the longitudinal direction of Example 4 concerning other examples of the present invention from the upper part. It is sectional drawing of the front-end | tip part along the longitudinal direction of Example 5 which concerns on other Example of this invention, and is the figure which looked at the blade from the lateral direction. It is the figure which looked at the tip part along the longitudinal direction of the blade of Example 6 concerning other examples of the present invention from the upper part. FIG. 14 is a diagram illustrating a relationship between the resistivity of a nonlinear resistance material layer and an electric field according to Example 6.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall schematic configuration diagram of a blade and a wind turbine generator according to a first embodiment of the present invention. As shown in FIG. 1, a wind power generator 50 includes a tower 4 provided with a grounding pole 5 and installed on the ground or at sea, a nacelle 3 attached to the top of the tower 4, and a main shaft inside the nacelle 3 (see FIG. 1). (Not shown), and a rotatable rotor composed of a plurality of blades 1 attached to the hub 2. Here, the blade 1 constituting the rotor is also referred to as a windmill blade. In addition, a generator (not shown) is connected to the main shaft via a gearbox (not shown), and the rotating force of the rotor is transmitted to the generator via the gearbox. . The rotor rotates when the blade 1 receives the wind, and the generator is rotated by the rotational force of the rotor to generate electric power. The blade 1 includes an outer skin (sometimes referred to as an outer surface) made of fiber reinforced plastic (FRP) and a main girder (not shown) arranged inside the outer skin.

  Although not shown, a wind direction and wind speed sensor for measuring a wind direction and a wind speed are installed on the nacelle 3, and a rotation speed sensor for detecting a rotation speed, a power generation sensor, and the like are provided in a generator (not shown). A power sensor for measuring the active power output from the machine is also installed. The wind power generator 50 includes a pitch angle adjusting device (not shown) for adjusting an angle (pitch angle) of the blade 1 with respect to the wind for each individual blade 1. The pitch angle adjusting device is configured to change the pitch angle of the blade 1 to adjust the wind force (air volume) received by the blade 1 to change the rotational energy of the rotor with respect to the wind. This makes it possible to control the rotation speed and the generated power in a wide wind speed range. The direction of the nacelle 3 is called a yaw angle, and the wind turbine generator 50 includes a yaw angle adjusting device (not shown) for controlling the direction of the nacelle 3, that is, the direction of the rotation surface of the rotor. Although FIG. 1 shows an example of the wind power generator 50 having three blades 1, the number of blades is not limited to three.

  FIG. 2 is a diagram showing one blade constituting the wind turbine blade shown in FIG. As shown in FIG. 2, a receptor 6 is installed near the tip of the blade 1 as a lightning protection device. Receptor 6 is electrically connected to ground electrode 5 by down conductor 7. An intermediate receptor (not shown) may be provided depending on the size of the blade 1. In this case, the intermediate receptor is also connected to the ground electrode 5 by the down conductor 7.

  The material and size of the receptor 6 are designed in consideration of lightning energy (charge amount). Of the main conductors, aluminum is preferred as the material of the receptor 6. If the receptor 6 is made of aluminum, aluminum is excellent in conductivity, so that internal heat generation due to current caused by lightning can be reduced. Further, since aluminum has excellent thermal conductivity, internal heat generation can be quickly dispersed. Further, aluminum is lighter than other main conductors, so that the centrifugal force acting on the receptor 6 can be reduced.

  Like the receptor 6, the material and thickness of the down conductor 7 are designed in consideration of the lightning energy (charge amount). Among the main conductors, an aluminum wire is preferable as the material of the down conductor 7. Although the aluminum wire has a lower conductivity than the copper wire, it is a lightweight structural material used as a main structural material. For this reason, even if the diameter is increased to ensure the same level of conductivity as copper, the weight of the wind turbine blade does not increase because it is a lightweight material. On the contrary, due to the feature of the structural material, the down conductor having sufficient strength to withstand the centrifugal force acting on the receptor 6 can be obtained due to the feature of the structural material.

  When a lightning strike occurs on the receptor 6, the lightning current is guided to the ground electrode 5 via the receptor 6 and the down conductor 7. As shown in FIG. 1, a nacelle 3 and a tower 4 exist in an energizing path from the down conductor 7 to the ground electrode 5, but a lightning current may energize the nacelle 3 and the tower 4, The conductor (not shown) and the lightning conductor in the tower (not shown) may be energized. One end of the lightning conductor in the nacelle is electrically connected to the down conductor 7, and the other end of the lightning conductor in the nacelle is electrically connected to the lightning conductor in the tower. One end of the lightning conductor in the tower is electrically connected to the lightning conductor in the nacelle, and the other end of the lightning conductor in the tower is electrically connected to the ground electrode 5. If the nacelle 3 and the tower 4 have sufficient processing ability as a conductor for lightning current, the installation of the lightning conductor in the nacelle and / or the lightning conductor in the tower may be omitted.

  FIG. 3 is a cross-sectional view of a tip portion of the blade 1 shown in FIG. 2 along the longitudinal direction, and is a view of the blade 1 shown in FIG. 2 as viewed from above (a direction perpendicular to the plane of the paper of FIG. 2). It is. As shown in FIG. 3, the receptor 6 attached near the tip of the blade 1 is fixed near the tip of the blade 1 by a receptor anchor 9, a fastening portion 10, and an adhesive 11. In some cases, the receptor 6 and the receptor anchor 9 are collectively referred to as a receptor. In the following, a description will be given separately of a receptor 6 for receiving lightning and a receptor anchor 9 for holding the receptor 6. The receptor 6 and the receptor anchor 9 may be configured as separate components, respectively, and the receptor 6 and the receptor anchor 9 may be integrally formed by molding, shaving, or using a 3D printer or the like. Further, the lightning strike may wear the receptor 6, and the receptor 6 may need to be replaced. In order to easily replace the receptor 6, it is preferable to provide a portion serving as a male screw on the receptor 6 and a portion serving as a female screw on the receptor anchor 9, and screw the receptor 6 into the receptor anchor 9 for connection. In this embodiment, the case where the receptor anchor 9 is provided will be described. However, the receptor anchor 9 is not necessarily required, and it is sufficient that the receptor 6 and one end of the down conductor 7 are electrically connected. In other words, when the receptor 6 and one end of the down conductor 7 are directly mechanically connected, or when the receptor 6 and one end of the down conductor 7 are connected via another member (for example, the receptor anchor 9). In some cases, it is only necessary that the receptor 6 and one end of the down conductor 7 be electrically connected.

  Further, as shown in FIG. 3, a part or all of the gap between the receptor anchor 9 and the blade 1 is filled with the adhesive 11. As the material of the adhesive 11, for example, a resin such as epoxy is selected, but the material is not limited to this.

  The fastening portion 10 electrically and mechanically connects the receptor anchor 9 and the down conductor 7. The terminal of the fastening portion 10 on the side of the receptor anchor 9 may be integrally formed with the receptor anchor 9 and the receptor 6. As a method of fastening the fastening portion 10, for example, a crimp terminal or a compression terminal is used. When fastening with crimp terminals, the fastening portion 10 can be made inexpensive. When fastening with the compression terminal, the entire terminal is compressed and connected, so that the mechanical load acting on the strand of the down conductor 7 can be reduced. As a result, the possibility that the strand breaks can be reduced, and the reliability of the down conductor 7 can be increased.

  In the blade 1, it is expected that lightning strikes the receptor 6. However, there is a case where the receptor 6 is actually removed and lightning strikes the main body of the blade 1. This principle will be described with reference to FIG. FIG. 4 is a cross-sectional view of the tip portion of the blade 1 shown in FIG. 2 along the longitudinal direction, and is a view of the blade 1 shown in FIG. 2 viewed from the lateral direction. FIG. The same components as those in FIG. 3 are denoted by the same reference numerals, and redundant description will be omitted below. When the thundercloud approaches the blade 1, the stepwise positive streamer 15 advances from the thundercloud toward the blade 1. As the forward streamer 15 advances, the electric field intensity around the blade 1 increases. As a result, the electric field strength around the down conductor 7 also increases, and a negative streamer 16 is generated from each part of the down conductor 7. The negative streamer 16 grows toward the inner surface of the blade 1, and negative charges are accumulated on the inner surface of the blade 1. On the other hand, positive charges are accumulated on the outer surface of the blade 1 so as to be attracted to the negative charges. During this time, the electric field strength around the receptor 6 is also high, and the negative streamer 16 is also generated from the receptor 6. The negative streamer 16 generated from the receptor 6 grows toward the positive charge accumulated on the outer surface of the blade 1 and also grows toward the positive streamer 15 that has evolved from the thundercloud. When the positive streamer 15 and the negative streamer 16 make contact at the contact point 17 between the positive and negative streamers, a lightning current is generated. At this time, a portion where the negative streamer 16 in contact with the positive streamer 15 is in contact with the blade 1 becomes a lightning point 18. With such a principle, when the thunder cloud approaches, the receptor 6 may be detached to strike the main body of the blade 1. Although FIG. 4 shows an example in which the positive streamer 15 advances from the thundercloud, a negative streamer may advance from the thundercloud. In this case as well, the basic principle is the same, and the positive and negative may be interchanged in the above description.

  In the above description, the lightning strike on the blade 1 main body by removing the receptor 6 is partly due to the accumulation of negative charges on the inner surface of the blade 1 and positive charges on the outer surface of the blade 1. That is, the influence of the electric charge accumulated on the outer surface or the inner surface of the blade 1 may be reduced or the electric charge may not be accumulated.

  FIG. 5 is a view of the blade 1 according to the present embodiment viewed from above at the tip along the longitudinal direction. The same reference numerals are given to the same components in FIG. 3, and the description thereof will be omitted. In FIG. 5, components existing inside the blade 1 are indicated by dotted lines. A non-linear resistance material layer 8 is applied to the outer surface of the blade 1 in order to reduce the influence of the electric charge accumulated on the outer surface of the blade 1 or to prevent the electric charge from being accumulated. For example, as shown in FIG. 6, the non-linear resistance material has a low electric resistance value and exhibits conductivity when an electric field having a predetermined electric field value or more acts thereon, and has a high electric resistance value when an electric field lower than the predetermined electric field value acts. It is a substance that becomes insulating. The nonlinear resistance material layer 8 is formed by adding zinc oxide or silicon carbide powder having nonlinear resistance characteristics to a synthetic resin such as epoxy. By adjusting the amount of addition, the nonlinear resistance characteristics can be set arbitrarily. By applying such a non-linear resistance material layer 8 to the outer surface of the blade 1, when the positive streamer 15 approaches, an electric field of a predetermined electric field value or more acts around the non-linear resistance material layer 8, and the non-linear resistance The electrical resistance value of the material layer 8 decreases. As a result, the influence of the positive charges accumulated on the outer surface of the blade 1 is reduced, or the accumulated positive charges are guided to the receptor 6. Thereby, the negative streamer 16 generated from the receptor 6 advances toward the positive streamer 15, so that the probability of a lightning strike on the receptor 6 can be increased. If the non-linear resistance material layer 8 is applied to the entire outer surface of the blade 1, the probability of lightning strike on the receptor 6 can be increased for lightning strike from any direction. Since the nonlinear resistance material layer 8 may be applied to the outer surface of the blade 1, it can be applied to the blade 1 of the wind power generator 50 already operating.

The nonlinear resistance material layer 8 may be configured to be applied only to a portion 10 m in the longitudinal direction from the tip of the blade 1. For example, Non-Patent Document 1 discloses a result of lightning strike observation for about 5 years for a wind farm in which 508 wind power generators are installed. The results of lightning observation show that 301 out of 304 lightning damage cases occurred within a range of 10 m from the blade tip, and 90% of 304 lightning damage cases were 4 m from the blade tip. It is disclosed that it occurs in a range. Therefore, by applying the non-linear resistance material layer 8 within a range of 10 m, preferably 4 m from the tip end of the blade 1 in the longitudinal direction, cost effectiveness can be improved.
In addition, Non-Patent Document 1 describes that the length of the blades provided in the 508 wind power generation devices is 35 m or more. On the other hand, the length of a blade of a high-output wind power generator is generally about 40 m. Therefore, the length of the blades provided in the 508 wind power generation devices can be considered to be 35 m or more and 40 m or less. Therefore, if the length of the blade is 40 m, the ratio of 4 m to the length of the blade is 10%, and 10 m is 25%. When the length of the blade is 35 m, the ratio of 4 m to the length of the blade is 11%, and 10 m is 29%. Therefore, it is preferable to apply the non-linear resistance material layer 8 limited to a range in the longitudinal direction from the tip of the blade where the ratio to the length of the blade is 10% or more and 29% or less.

  FIG. 7 is a cross-sectional view of the tip portion along the longitudinal direction of the blade 1 shown in FIG. 5, and is a view of the blade 1 shown in FIG. The same reference numerals are given to the same components in FIG. 4, and the description thereof will be omitted. As shown in FIG. 7, the nonlinear resistance material layer 8 is in contact with the receptor 6. By doing so, the positive charges accumulated on the outer surface of the blade 1 can be reliably guided to the receptor 6.

  The non-linear resistance material layer 8 may be inside the coating 13 as shown in FIG. That is, the non-linear resistance material layer 8 is applied to the outer surface of the blade 1, and the coating 13 is provided outside the non-linear resistance material layer 8. When the wind power generator 50 is operating, that is, when the blade 1 is rotating, the blade 1 receives wind pressure and wears little by little. To prevent this, the blade 1 is usually provided with a coating 13. By coating the non-linear resistance material layer 8 on the outer surface of the blade 1 and further providing the coating 13 on the outside thereof, the probability of lightning strike on the receptor 6 is increased, and the blade 1 and the non-linear resistance material layer 8 are worn by wind pressure. Can be prevented.

As described above, according to the present embodiment, it is possible to provide a blade and a wind turbine that can suppress lightning damage to the blade body.
Further, according to this embodiment, since the coating is further applied so as to cover the non-linear resistance material layer applied to the outer surface of the blade, it is possible to suppress the abrasion of the blade and the non-linear resistance material layer due to wind pressure. Become.

  FIG. 8 is a cross-sectional view of a tip portion along a longitudinal direction of a blade according to a second embodiment of the present invention, which is a view of the blade viewed from a lateral direction. This embodiment is different from the first embodiment in that the non-linear resistance material layer 8 is applied to the inner surface of the blade 1. In FIG. 8, the same components as those in the above-described first embodiment are denoted by the same reference numerals, and redundant description will be omitted below.

  As shown in FIG. 8, the non-linear resistance material layer 8 is applied to the inner surface of the blade 1. With such a configuration, the influence of the negative charges (FIG. 4) accumulated on the inner surface of the blade 1 can be reduced, or the accumulated negative charges can be guided to the receptor 6. As a result, the negative streamer 16 generated from the receptor 6 advances toward the positive streamer 15, so that the probability of lightning strike on the receptor 6 can be increased. Further, since the inner surface of the blade 1 is not affected by wind pressure, the non-linear resistance material layer 8 does not wear. For this reason, the non-linear resistance material layer 8 can exhibit an effect for a long time without taking special measures.

  As described above, according to the present embodiment, in addition to the effects of the first embodiment, it is possible to extend the life of the nonlinear resistance material layer.

  FIG. 9 is a view of a blade along a longitudinal direction of a blade according to a third embodiment of the present invention as viewed from above. In this embodiment, the non-linear resistance material layer 8 is applied to the outer surface of the blade 1 so as to cover the fastening portion 10 and the receptor anchor 9 and cover at least a part of the down conductor 7 on the projection surface. This is different from the first embodiment. In FIG. 9, the same components as those in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted below. In FIG. 9, components existing inside the blade 1 are indicated by dotted lines.

As shown in FIG. 9, the non-linear resistance material layer 8 is formed on the blade 1 such that the down conductor 7 covers at least a part of the portion projected on the suction surface when the suction surface is viewed from the pressure surface of the blade 1. It is applied to the outer surface. Similarly, the non-linear resistance material layer 8 is applied to the outer surface of the blade 1 so as to cover at least a part of the portion where the down conductor 7 is projected onto the pressure surface when the pressure surface is viewed from the suction surface of the blade 1. Have been.
With such a configuration, the effect of the charges accumulated by the negative streamer 16 generated from the down conductor 7 is reduced, or the accumulated charges are guided to the receptor 6, particularly in a portion that is particularly cost-effective. be able to.

  As shown in FIG. 9, the non-linear resistance material layer 8 is formed such that the receptor anchor 9 covers at least a part of the portion projected onto the suction surface when the suction surface is viewed from the pressure surface of the blade 1. 1 is applied to the outer surface. Similarly, the non-linear resistance material layer 8 is applied to the surface of the blade 1 so that the receptor anchor 9 covers at least a part of the portion projected onto the pressure surface when the pressure surface is viewed from the suction surface of the blade 1. ing. By doing so, the influence of the electric charge accumulated by the negative streamer 16 generated from the receptor anchor 9 can be reduced, or the accumulated electric charge can be guided to the receptor 6. Thereby, the probability of lightning strike on the receptor 6 can be further increased.

  FIG. 10 is a diagram illustrating a first modification of the blade illustrated in FIG. 9. The same reference numerals are given to the same components in FIG. 9, and the description thereof will be omitted below. As shown in FIG. 10, the non-linear resistance material layer 8 is applied to the portion from the receptor 6 to the tip of the blade 1 in addition to the portion shown in FIG. In other words, the non-linear resistance material layer 8 is applied so as to extend from the receptor 6 to the tip of the blade 1. With this configuration, the probability of lightning strike on the receptor 6 can be further increased as compared with the configuration in FIG.

  FIG. 11 is a diagram illustrating a second modification of the blade illustrated in FIG. 9. The same reference numerals are given to the same components in FIG. 10, and the description thereof will be omitted below. As shown in FIG. 11, the non-linear resistance material layer 8 is applied to the portion from the receptor 6 to the front edge side and the rear edge side in addition to the portion shown in FIG. However, the present invention is not limited to this, and the configuration may be such that the non-linear resistance material layer 8 is applied to a portion from the receptor 6 to the front edge side or the rear edge side. In other words, the non-linear resistance material layer 8 is applied so as to extend from the receptor 6 to the leading edge side and / or the trailing edge side. With this configuration, the probability of lightning strike on the receptor 6 can be further increased as compared with the configuration of FIG.

  As described above, according to the present embodiment, in addition to the effects of the first embodiment, it is possible to realize a configuration in which the non-linear resistance material layer is applied to the outer surface of the blade limited to a particularly cost-effective portion. .

  FIG. 12 is a diagram of a blade 1 of Example 4 according to another embodiment of the present invention, as viewed from above, along the longitudinal direction. This embodiment is different from the first embodiment in that a diverter strip 12 is provided on the outer surface of the blade 1. 12, the same components as those in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted below. In FIG. 12, components existing inside the blade 1 are indicated by dotted lines.

  As shown in FIG. 12, a diverter strip 12 is attached to the outer surface of the blade 1. The diverter strip 12 guides the positive streamer 15, which is about to strike the outer surface of the blade 1, toward the diverter strip 12. However, the divertor strip 12 does not have a large peak current resistance and a large charge resistance, and there is a problem that the diverter strip 12 is worn out by receiving a lightning strike having a large peak current or a lightning stroke having a large charge amount a plurality of times. Then, the non-linear resistance material layer 8 is applied to the outer surface of the surrounding blade 1 to which the diverter strip 12 is attached. Thus, the probability of lightning strike on the receptor 6 can be increased by the effect of the application of the nonlinear resistance material layer 8, and the diverter strip 12 can protect the lightning strike on the outer surface of the blade 1 main body. By doing so, the frequency of replacing the diverter strip 12 can be reduced.

  As described above, according to this embodiment, in addition to the effects of the first embodiment, it is possible to further suppress the lightning strike on the outer surface of the blade 1 main body while increasing the probability of lightning strike on the receptor 6.

  FIG. 13 is a cross-sectional view of a tip portion along a longitudinal direction of a blade 1 of Example 5 according to another embodiment of the present invention, and is a diagram of the blade viewed from a lateral direction. The difference from the first embodiment is that the receptor 6a is provided at the tip of the blade 1. In FIG. 13, the same components as those in FIG. 7 are denoted by the same reference numerals, and redundant description will be omitted below.

  As shown in FIG. 13, the receptor 6a is attached to the tip of the blade 1. In Japan, especially in the Sea of Japan side, high-energy lightning called winter lightning is observed, and a large-volume receptor 6a attached to the tip of the blade 1 shown in FIG. 13 may be used. Even in such a configuration, by applying the non-linear resistance material layer 8 to the outer surface of the blade 1, the probability of lightning strike on the receptor 6a can be increased. Note that the shape of the receptor 6a is not limited to the shape shown in FIG. 13, but may be any desired shape.

  As described above, according to the present embodiment, it is possible to achieve the same effects as those of the first embodiment.

  FIG. 14 is a diagram of a blade 1 of Example 6 according to another embodiment of the present invention, as viewed from above, along the longitudinal direction. The present embodiment is different from the first embodiment in that the first non-linear resistance material layer 8a and the second non-linear resistance material layer 8b having different characteristics are applied to the outer surface of the blade 1. 14, the same components as those in FIG. 5 are denoted by the same reference numerals, and redundant description is omitted below. In FIG. 14, components existing inside the blade 1 are indicated by dotted lines.

As shown in FIG. 14, the first nonlinear resistance material layer 8a is applied to a portion closer to the receptor 6 than the second nonlinear resistance material layer 8b. Here, FIG. 15 shows the relationship between the resistivity and the electric field of the first nonlinear resistance material layer 8a and the second nonlinear resistance material layer 8b according to the present embodiment, respectively. As shown in FIG. 15, the first non-linear resistance material layer 8a has a characteristic that the resistivity is greatly reduced in an electric field higher than that of the second non-linear resistance material layer 8b. As shown in FIG. 14, by adopting a configuration in which the first nonlinear resistance material layer 8a and the second nonlinear resistance material layer 8b are applied to the outer surface of the blade 1, the probability of lightning strike on the receptor 6 is further increased. be able to.
In this embodiment, the example in which the first nonlinear resistance material layer 8a and the second nonlinear resistance material layer 8b are used has been described. However, the first nonlinear resistance material layer 8a and the second nonlinear resistance material layer 8b are not used. May be provided with at least one or more different nonlinear resistance material layers having different relationships between resistivity and electric field. For example, a configuration may be adopted in which a non-linear resistance material layer is provided such that the relationship between the resistivity and the electric field changes continuously as the distance from the receptor 6 increases.

  Note that the present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described above. A part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of one embodiment can be added to the configuration of another embodiment.

DESCRIPTION OF SYMBOLS 1 ... Blade 2 ... Hub 3 ... Nacell 4 ... Tower 5 ... Grounding pole 6, 6a ... Receptor 7 ... Down conductor 8, 8a, 8b ... Nonlinear resistance material layer 9 ... Receptor anchor 10 ... Fastening part 11 ... Adhesive 12 ... Divertor Strip 13 Painting 15 Positive streamer 16 Negative streamer 17 Contact point 18 between positive streamer and negative streamer 18 Lightning point 50 Wind power generator

Claims (16)

The blade body,
At least one receptor mounted near the tip or tip of the blade body;
A blade electrically connected to the receptor, having a down conductor installed inside the blade body,
Having a non-linear resistance material layer on the outer surface or inner surface of the blade body,
The non-linear resistance material layer has a low electric resistance value when an electric field of a predetermined electric field value or more acts, and becomes conductive, and has a high electric resistance value when a electric field lower than the predetermined electric field value acts. A blade. The blade according to claim 1,
The blade according to claim 1, wherein the non-linear resistance material layer is applied to an outer surface or an inner surface of the blade body. The blade according to claim 2,
The blade is characterized in that the blade body is painted including a portion having the non-linear resistance material layer or corresponding to a portion having the non-linear resistance material layer. The blade according to any one of claims 1 to 3,
The non-linear resistance material layer includes at least a part of a portion where the down conductor is projected from the pressure surface of the blade body toward the suction surface toward the suction surface of the blade body, and a pressure surface from the suction surface of the blade body. Wherein the down conductor is provided so as to cover at least a part of a portion projected onto the pressure surface side of the blade body. The blade according to claim 4,
The receptor is fixed to a receptor anchor electrically connected to the receptor, and the down conductor is electrically connected to the receptor anchor,
The non-linear resistance material layer includes at least a part of a portion where the receptor anchor is projected from the pressure surface of the blade body toward the suction surface toward the suction surface of the blade body, and a pressure surface from the suction surface of the blade body. The blade is characterized in that the receptor anchor is provided so as to cover at least a part of the portion projected toward the pressure surface side of the blade body toward the blade body. The blade according to claim 5,
The blade according to claim 1, wherein the non-linear resistance material layer extends from the receptor to a tip portion of the blade body. The blade according to claim 6,
The blade according to claim 1, wherein the non-linear resistance material layer extends from the receptor to a front edge side and / or a rear edge side of the blade main body. The blade according to any one of claims 1 to 3,
A blade, wherein the receptor is provided at a tip portion of the blade main body. The blade according to any one of claims 1 to 3,
The blade, wherein the non-linear resistance material layer is provided in a range from 4 m to 10 m in a longitudinal direction from a tip end of the blade main body. The blade according to any one of claims 1 to 3,
The blade, wherein the non-linear resistance material layer is provided in a range in a longitudinal direction from a tip portion of the blade main body in which a ratio to a length of the blade is 10% or more and 29% or less. The blade according to any one of claims 1 to 3,
Having a diverter strip attached to the outer surface of the blade body,
The blade according to claim 1, wherein the non-linear resistance material layer is provided so as to cover at least a part of a periphery of the blade body to which the diverter strip is attached. The blade according to any one of claims 1 to 3,
The nonlinear resistance material layer has a first nonlinear resistance material layer and a second nonlinear resistance material layer,
The first non-linear resistance material layer is closer to the receptor than the second non-linear resistance material layer, and the first non-linear resistance material layer has a greatly reduced resistivity in an electric field higher than the second non-linear resistance material layer. A blade characterized in that the blade has the following characteristics. At least, a wind turbine generator having a rotor having a blade that rotates in response to wind, and a nacelle that houses a generator that generates electric power using the rotational energy of the rotor,
The blade includes a blade body, at least one receptor attached near the tip or the tip of the blade body, and a down conductor electrically connected to the receptor and installed inside the blade body. Prepared,
Having a non-linear resistance material layer on the outer surface or inner surface of the blade body,
The non-linear resistance material layer has a low electric resistance and becomes conductive when an electric field having a predetermined electric field or more acts thereon, and has a high electric resistance when an electric field lower than the predetermined electric field acts. A wind power generator. The wind power generator according to claim 13,
The wind power generator, wherein the non-linear resistance material layer is applied to an outer surface or an inner surface of the blade body. The wind power generator according to claim 13 or claim 14,
The wind power generator, wherein the non-linear resistance material layer is provided in a range of 4 m or more and 10 m in a longitudinal direction from a tip portion of the blade main body. The wind power generator according to claim 13 or claim 14,
The wind power generator, wherein the non-linear resistance material layer is provided in a range in a longitudinal direction from a tip end of the blade main body in which a ratio to a blade length is 10% or more and 29% or less.

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