JP2012117447A - Lightning arrester device for wind turbine rotor blades and wind turbine generator equipped with same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve lightning resistance without raising the level of the fluid noise caused by lightning arresting members arranged on the surface of wind turbine blades by a simple structure.SOLUTION: A lightning arrester device A for wind turbine rotor blades provided with diverter strips 18 as the lightning arresting members projecting on the surface of the wind turbine blades 9 extending in the radial direction from a rotor head rotatably pivoted has noise suppressing structure A' suppressing generation of Karman vortices becoming a cause of noise on the downstream side of the diverter strips 18 with respect to an airstream flowing on the surface of the wind turbine blades 9 when the wind turbine rotor blades rotate. The noise suppressing structure A' is of an array structure in which the diverter strips 18a-18d are arrayed in multiple zigzag lines along the flowing direction of the airstream on the surface of the wind turbine blades 9, and the interval S of these multiple diverter strips 18a-18d is set so as to match the generation interval of the Karman vortices.

Description

  The present invention relates to a wind turbine rotor blade having a lightning arrester projecting on the surface of the wind turbine blade, and more particularly to a lightning arrester for a wind turbine rotor blade that suppresses noise generated by the lightning arrester member and a wind turbine generator having the same. Is.

A standard wind turbine generator includes wind turbine rotor blades having several wind turbine blades extending in a radial direction around the rotor head, and the rotor head is pivoted on a nacelle supported horizontally at the upper end of the tower. A generator installed in the nacelle is driven by the rotation of the wind turbine rotor blades to generate power.
Since this type of wind turbine generator is particularly susceptible to lightning strikes on the wind turbine blades, a receptor (lightning receiving member) is provided as a lightning arrester on the wind turbine blades as disclosed in Patent Document 1. In this case, a receptor is provided at the tip of the blade where lightning strikes most easily, and a lightning conductor (down conductor) extending from this receptor passes through the interior of the wind turbine blade and is grounded to the ground via the nacelle and tower. It is designed to guide the lightning current when lightning strikes into the ground.

  By providing such a receptor, it is possible to receive lightning strikes to the tip of the wing almost certainly, but if lightning strikes at a position shifted from the tip of the wing by a few meters to the blade root, There is a risk of damaging the windmill blade by melting the blade skin and reaching the inside of the blade. In the future, as wind turbine generators increase in size, the blade length tends to become longer, and in the vicinity of the ocean, the overall lightning strike capture rate is reduced due to the adhesion of salt to the blade surface. There is a tendency for the risk of lightning strikes to increase.

  Therefore, a large number of divertor strips, which are button-shaped metal pieces, are provided on the surface of the blade other than the tip of the blade where the receptor is provided, and lightning strikes occur when lightning strikes other than the tip of the blade using these divertor strips. Electric current can be caused to flow along the surface of the wind turbine blade via each diverter strip and be directed to the aforementioned receptor. In this way, since it is not necessary to provide a lightning conductor in each diverter strip, the lightning resistance of the wind turbine blade can be improved with a simple structure.

JP 2010-223148 A

  However, when a large number of divertor strips are installed on the surface of the wind turbine blade as described above, the divertor strip protruding from the surface of the wind turbine blade causes the air current flowing on the surface of the wind turbine blade to rotate when the wind turbine rotor blade rotates. A Karman vortex (or Karman vortex street) was generated downstream of the divertor strip, which caused annoying fluid noise. Embedding the divertor strip so that the divertor strip is flush with the surface of the wind turbine blade will eliminate the fluid noise problem, but this will improve the lightning strikeability and lightning current transmission capability of the divertor strip. In addition, the concave portion for embedding the diverter strip is generated on the surface of the wind turbine blade, and stress concentrates around the concave portion, which causes a decrease in the strength of the wind turbine blade.

  The present invention has been made in view of the above circumstances, and has a simple structure, and wind turbine rotation that can improve the lightning resistance performance without increasing the fluid noise level due to the lightning arresting member provided on the surface of the wind turbine blade. An object of the present invention is to provide a lightning arrester for a wing and a wind turbine generator having the same.

In order to solve the above problems, the present invention employs the following means.
That is, the first aspect of the lightning arrester of the wind turbine rotor blade according to the present invention is a lightning arrester of the wind turbine rotor blade in which a lightning arresting member projects from the surface of the wind turbine blade extending radially from the rotor head rotatably supported. The apparatus has a noise suppression structure that suppresses generation of Karman vortices on the downstream side of the lightning protection member with respect to the airflow flowing on the surface of the wind turbine blade when the wind turbine rotor blade rotates. .

  According to the above configuration, since the noise suppression structure is provided, the airflow flowing on the surface of the wind turbine blade is suppressed from generating Karman vortices on the downstream side of the lightning protection member protruding from the surface of the wind turbine blade. The fluid noise caused by the generation of Karman vortex is suppressed.

  According to a second aspect of the lightning arrester of the wind turbine rotor blade according to the present invention, in the first aspect, the noise suppression structure is formed on the surface of the windmill blade in the direction along the flow direction of the airflow. It is an arrangement structure in which a plurality of members are arranged in a meandering manner, and the interval between the plurality of lightning protection members is adjusted to the generation interval of the Karman vortex.

According to the above configuration, since the next lightning protection member is disposed at the position of Karman vortex to be alternately generated on the downstream side of the lightning protection member on the most upstream side with respect to the airflow flowing on the surface of the wind turbine blade, Generation of Karman vortex is hindered. For this reason, generation | occurrence | production of the fluid noise resulting from generation | occurrence | production of Karman vortex is suppressed. Note that Karman vortices are unlikely to occur on the downstream side of the lightning protection member located on the most downstream side with respect to the airflow. This is because the upstream lightning protection members arranged in a meandering manner disturb the airflow.
For example, the Karman vortex fluid noise generated on the downstream side of a single lightning arrester is a single frequency, that is, a pure sound, and can be easily heard by the human ear as an abnormal sound, but a plurality of lightning arresters arranged in a meandering manner as described above The sound generated by the airflow generated downstream is a broadband sound and is of the same quality as the noise generated by the wind turbine blades, so that it is difficult for the human ear to capture the noise. For this reason, the fluid noise level is not increased.

  According to a third aspect of the lightning arrester for a wind turbine rotor blade according to the present invention, in the second aspect, among the plurality of lightning arresting members, the size of the lightning arresting member on the downstream side with respect to the flow direction of the airflow. This is characterized in that it is smaller than the lightning protection member on the upstream side.

  According to the above configuration, the occurrence of Karman vortices at the rear of the lightning arrester on the upstream side is inhibited by the lightning arrester on the downstream side with respect to the airflow flowing on the surface of the wind turbine blade, and the size of the lightning arrester on the downstream side is large. Is smaller than the lightning arrester on the upstream side, so the Karman vortex generated by the lightning arrester on the downstream side is smaller, which reduces the fluid noise level of the Karman vortex generated from the entire lightning arrester. To do.

  Moreover, the 4th aspect of the lightning arrester of the windmill rotor blade which concerns on this invention WHEREIN: In the said 2nd or 3rd aspect, these lightning protection members were installed at unequal intervals, It is characterized by the above-mentioned. As a result, the airflow on the downstream side of the lightning arrester member on the upstream side tends to be turbulent with respect to the airflow flowing on the surface of the wind turbine blade, so that it is likely to occur alternately at equal intervals on the downstream side of the lightning arrester member on the upstream side. The Karman vortex is easily destroyed. For this reason, it can contribute to the fluid noise level fall resulting from a Karman vortex.

  According to a fifth aspect of the lightning arrester for a wind turbine rotor blade according to the present invention, in the first aspect, the noise suppression structure is configured such that the shape of the lightning arresting member is asymmetrical with respect to the flow direction of the airflow. It is characterized by a shaped structure. This creates a speed difference between the airflows flowing on both sides of the lightning protection member, which causes the airflow downstream of the lightning protection member to become turbulent and stop generating Karman vortices. Can be suppressed.

  According to a sixth aspect of the lightning arrester of the wind turbine rotor blade according to the present invention, in the first aspect, the noise suppression structure has a streamline shape with respect to a flow direction of the airflow. It is the structure made into. Thereby, the airflow downstream of the lightning protection member can be adjusted, the generation of Karman vortex can be prevented, and the fluid noise can be suppressed.

  Further, according to a seventh aspect of the lightning arrester for the wind turbine rotor blade according to the present invention, in any one of the first to sixth aspects, the lightning arrester member is provided in the vicinity of a front edge portion of the wind turbine blade. It is characterized by that. Since the velocity of the airflow is slow near the front edge of the wind turbine blade, Karman vortices are unlikely to occur on the downstream side of the lightning protection member, which can more effectively suppress the generation of fluid noise.

  According to an eighth aspect of the lightning arrester of the wind turbine rotor blade according to the present invention, in any one of the first to seventh aspects, the lightning arresting member causes a lightning current to flow along the surface of the windmill blade. The divertor strip leads to a ground member provided on the wind turbine blade. In this way, since it is not necessary to provide a lightning conductor in the diverter strip, lightning damage to the wind turbine blade can be minimized with a simple structure.

  Further, in the lightning arrester for a wind turbine rotor blade according to the present invention, in any one of the second to eighth aspects, the noise suppression structure is applied to a range from the blade tip of the wind turbine blade to 20% of the blade length. It is characterized by that. Since the noise level emitted from the wind turbine blade increases in proportion to the sixth power of the radius of the wind turbine blade, the generation level of fluid noise is highest in the range from the blade tip to 20% of the blade length. For this reason, by applying the noise suppression structure only to the range up to 20% from the blade tip, it is possible to relatively freely arrange the lightning protection member and the like in other parts, thereby increasing the fluid noise level. The lightning resistance can be improved.

  And the wind power generator concerning the present invention was provided with the lightning arrester of the windmill rotor blade of each above-mentioned mode. Thereby, said each effect | action and effect can be show | played.

  As described above, according to the lightning arrester of the wind turbine rotor blade and the wind turbine generator provided with the same according to the present invention, the fluid noise level due to the lightning arrester member provided on the surface of the wind turbine blade is not increased by a simple structure. , Lightning resistance can be improved.

It is a side view which shows an example of the wind power generator which can apply the lightning arrester of the windmill rotor blade which concerns on this invention. It is the perspective view which expanded the windmill blade of the wind power generator shown in FIG. It is a figure which expands the III section of FIG. 2, and shows 1st Embodiment of this invention. (A) is a figure which shows the state which Karman vortex generate | occur | produced in the downstream of one diverter strip, (b) shows the state where Karman vortex collapses by the several divertor strips arranged meanderingly FIG. (A) is a figure which shows frequency distribution of the fluid noise in case Karman vortex generate | occur | produces in the downstream of one diverter strip, (b) is the downstream of several divertor strips arranged meanderingly It is a figure which shows the frequency distribution of the fluid noise which the airflow which generate | occur | produces occurs. It is a figure which shows 2nd Embodiment of this invention. It is a figure which shows 3rd Embodiment of this invention. It is a figure which shows 4th Embodiment of this invention, (a) is the figure which formed the divertor strip in the elliptical shape which inclined, and was made into the asymmetrical shape with respect to the flow direction of an airflow, (b) is circular. It is the figure which cut off some divertor strips of this and made the shape asymmetrical with respect to the flow direction of airflow. FIG. 10 is a diagram showing a fifth embodiment of the present invention, in which (a) is a plan view of a divertor strip formed into a waterdrop-type streamline shape, and (b) is a rounded shoulder portion of the diverter strip. It is the side view formed in the streamline shape. It is an expansion perspective view of the windmill blade which shows 6th Embodiment of this invention. It is the figure which showed the relationship between the distance from the blade root of a windmill blade, and the sound power level per unit length of a windmill blade.

  Hereinafter, a plurality of embodiments of a wind turbine generator according to the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a side view showing an example of a wind turbine generator to which a lightning arrester for a wind turbine rotor blade according to the present invention can be applied. This wind power generator 1 includes, for example, a tower 4 erected on a reinforced concrete foundation 3 installed on the ground surface 2, a nacelle 5 installed at the upper end of the tower 4, and a substantially horizontal lateral direction. And a rotor head 6 provided on the front end side of the nacelle 5 so as to be rotatable about a rotation axis.

  The tower 4 is a monopole type made of steel pipe, and a base plate 7 made of, for example, a steel plate is fixed to the lower end portion of the tower 4, and the base plate 7 is fastened and fixed to the foundation 3 with a number of anchor bolts 8. A plurality of (for example, three) wind turbine blades 9 extending in the radial direction are attached to the rotor head 6 to form a wind turbine rotor blade 10. A generator 11 is accommodated and installed in the nacelle 5. A rotary shaft 12 of the head 6 is connected to a main shaft of the generator 11 via a speed increaser (not shown). For this reason, the wind force of the external wind which hits the windmill blade 9 is converted into a rotational force that rotates the windmill rotor blade 10 and the rotating shaft 12, and the generator 11 is driven to generate power.

  The nacelle 5 can turn in the horizontal direction at the upper end of the tower 4 together with the wind turbine rotor blade 10. An appropriate wind direction anemometer 14 for measuring the wind direction and wind speed value around the nacelle 5 and a lightning rod 15 for avoiding lightning strike are installed at appropriate positions (for example, the upper part) of the nacelle 5. The nacelle 5 is controlled by a drive device and a control device (not shown) so that the nacelle 5 can always generate power efficiently in the windward direction. The nacelle 5 and the wind turbine blade 9 are formed by, for example, FRP molding.

  FIG. 2 is an enlarged perspective view of one of the wind turbine blades 9. A lightning arrester A according to the present invention is provided on the surface of each wind turbine blade 9. In this lightning arrester A, one receptor 17 and a number of diverter strips 18 are provided on the surface of the wind turbine blade 9 as lightning protection members. The receptor 17 is a known lightning protection member (lightning protection member), and is provided at the tip of the wind turbine blade 9 where lightning strikes most easily, and is generally formed in a circular shape with a diameter of several centimeters or a shape that follows the shape of the blade tip. Has been. A lightning conductor (down conductor) 19 extending from the receptor 17 passes through the inside of the wind turbine blade 9 and is connected to the ground via the nacelle 5 and the tower 4, and the lightning current when a lightning strikes the receptor 17 enters the ground. It comes to lead.

  On the other hand, the diverter strip 18 is also a known lightning protection member, and is generally formed in a disk shape (button shape) having a diameter of about several millimeters and a thickness of 1 mm or less, in which copper is plated with nickel, or a rectangular shape. The surface of the wing 9 is fixed to a range where the receptor 17 is not provided, that is, a range along the longitudinal direction other than the tip of the wing by an adhesive having high weather resistance. Therefore, a large number of diverter strips 18 are scattered and projected on the surface of the wind turbine blade 9.

  A lightning conductor 19 is not connected to each diverter strip 18, but by installing a large number of metal diverter strips 18 in such a wide range, a lightning current when a lightning strike occurs in a place other than the receptor 17, It can flow along the surface of the wind turbine blade 9 via a plurality of diverter strips 18, and can be led to a receptor 17 connected to a lightning conductor (down conductor) 19. Thereby, damage to the wind turbine blade 9 due to lightning can be prevented.

  When a large number of diverter strips 18 are projected on the blade surface of the wind turbine blade 9 as described above, the air current flowing on the surface of the wind turbine blade 9 is rotated downstream of the diverter strip 18 when the wind turbine rotor blade 10 rotates. A Karman vortex (or Karman vortex street) is generated, which causes annoying fluid noise. For this reason, in the lightning arrester A according to the present invention, a noise suppression structure that suppresses the generation of Karman vortices on the downstream side of the diverter strip 18 with respect to the airflow flowing on the surface of the wind turbine blade 9 when the wind turbine rotor blade 10 rotates. Is provided.

  FIG. 3 is a diagram showing the noise suppression structure A ′ according to the first embodiment of the present invention by enlarging the III part of FIG. 2. As shown in FIG. 3, for example, four diverter strips 18 provided on the surface of the wind turbine blade 9 constitute a group G 1, and these groups G 1 are arranged in the longitudinal direction of the wind turbine blade 9. A plurality of sets are arranged along. The installation interval of each group G1 is 1/10 or less of the diameter of the diverter strip 18, for example, about 1 mm. In FIG. 3, the symbols of the divertor strip 18 in each group G1 are 18a, 18b, 18c, and 18d from the front edge 9a side of the wind turbine blade 9. In each group G1, the four diverter strips 18a to 18d are arranged meandering along the direction along the flow direction of the airflow flowing on the surface of the wind turbine blade 9.

  Each group G <b> 1 is provided near the front edge of the wind turbine blade 9. As shown in FIG. 2, the vicinity of the front edge of the wind turbine blade 9 is a range from the front edge 9 a of the wind turbine blade 9 to the thickest portion of the wind turbine blade 9 (near the lightning conductor 19).

  As shown in FIG. 4 (a), when one diverter strip 18 is provided on the surface of the wind turbine blade 9, Karman vortices are alternately arranged on the downstream side of the diverter strip 18 as described above. Occurs, and fluid noise is generated. Therefore, in the present invention, as shown in FIGS. 3 and 4 (b), the installation interval S of the four diverter strips 18a to 18d is substantially matched to the generation interval of Karman vortices. Specifically, when the shape of the diverter strips 18a to 18d is circular (short cylindrical shape), Karman vortices are periodically generated at intervals twice as large as the diameter thereof. Preferably, the strips 18a to 18d are arranged at an interval twice the diameter of the strips 18a to 18d.

  As described above, in the lightning arrester A according to the present invention, a plurality of diverter strips 18 are grouped and arranged on the surface of the wind turbine blade 9, and Karman vortices that cause noise are generated on the downstream side of the diverter strips 18. Since the noise suppression structure A ′ that suppresses the generation of the airflow, the airflow flowing on the surface of the wind turbine blade 9 generates a Karman vortex on the downstream side of the divertor strip 18 to increase the fluid noise level. The lightning performance can be improved by the diverter strip 18 while eliminating.

  In particular, a plurality (four in this case) of diverter strips 18a to 18d are arranged as one group G1, and a plurality of these groups G1 are arranged along the longitudinal direction at the front edge of the wind turbine blade 9, and each group G1 has a diverter. Since the strips 18a to 18d meander in the direction along the flow direction of the relative air flow, and the installation interval S of each divertor strip 18a to 18d is adjusted to the generation interval of the Karman vortex, it flows on the surface of the wind turbine blade 9. The next diverter strip 18b is located at the position of the first Karman vortex to be generated downstream of the diverter strip 18a that is most upstream with respect to the airflow. For this reason, the generation of the first Karman vortex is inhibited and the following Karman vortices cannot be generated, and thus the generation of fluid noise due to the generation of Karman vortices (vortex streets) is suppressed. Note that Karman vortices are unlikely to occur on the downstream side of the divertor strip 18d located at the rearmost portion with respect to the airflow direction. This is because the air stream is disturbed by the upstream diverter strips 18a to 18c arranged in a meandering manner, resulting in uneven flow on both sides of the rearmost diverter strip 18d.

For example, the Karman vortex fluid noise generated on the downstream side of a single divertor strip 18 is a so-called pure sound having a high volume Lp only at a specific frequency f as shown in FIG. Easy to hear in human ear.
On the other hand, the sound generated by the airflow generated downstream of the plurality of diverter strips 18 meandered as described above has an averaged distribution of the frequency f as shown in FIG. 5B. Since it is a wideband sound, the maximum level of the volume Lp is low, and the sound quality is similar to the windmill sound (wind noise) generated by the windmill blade 9, it is difficult for the human ear to catch it as an abnormal sound. For this reason, the overall fluid noise level of the wind turbine generator 1 is not increased.

  A plurality of sets of groups G1 having four diverter strips 18a to 18d are arranged in the vicinity of the front edge along the longitudinal direction of the wind turbine blade 9, and the vicinity of the front edge of the wind turbine blade 9 has an air velocity. Therefore, Karman vortices are unlikely to be generated downstream of the diverter strips 18a to 18d, and the generation of fluid noise can be more effectively suppressed in this respect.

  In this embodiment, among the lightning protection members provided on the wind turbine blade 9, only the lightning protection member installed at the tip of the wind turbine blade 9 is the receptor 17 to which the lightning conductor 19 is connected, and other lightning protection members are used. Since the lightning current flows along the surface of the wind turbine blade 9 and the diverter strip 18 is led to the receptor 17 connected to the lightning conductor (down conductor) 19, a large number of lightning conductors 19 are provided inside the wind turbine blade 9. There is no need. Therefore, lightning damage to the wind turbine blade 9 can be minimized with a simple structure.

[Second Embodiment]
FIG. 6 is a diagram showing a second embodiment of the lightning arrester according to the present invention.
In the noise suppression structure B ′ of the lightning arrester B in the second embodiment, the diverter strips 18 that are a plurality of lightning arresting members provided on the surface of the wind turbine blade 9 constitute, for example, three groups G2. These groups G2 are arranged in a plurality along the longitudinal direction of the wind turbine blade 9. Each group G2 is arranged in the vicinity of the front edge portion of the wind turbine blade 9 as in the group G1 of the diverter strip 18 in the first embodiment.

  In each group G2, three disc-shaped (button-shaped) diverter strips 18e, 18f, and 18g are arranged meandering along the flow direction of the airflow flowing on the surface of the wind turbine blade 9. The interval between the three diverter strips 18e, 18f, and 18g is generally matched to the Karman vortex generation interval, as in the first embodiment. Of these three diverter strips 18e, 18f, 18g, the diverter strips 18f, 18g on the downstream side with respect to the flow direction of the airflow have the size (diameter) of the diverter strip 18e on the upstream side. Is smaller than For example, the diameter of the diverter strips 18f and 18g is set to ½ of the diameter of the diverter strip 18e. The diameter may be gradually reduced to 18e> 18f> 18g.

  In the case of such a noise suppression structure B ′, Karman vortices are generated at the rear part of the diverter strip 18e on the upstream side by the diverter strips 18f and 18g on the downstream side with respect to the airflow flowing on the surface of the wind turbine blade 9. Is inhibited. In addition, since the downstream diverter strips 18f and 18g are smaller in size than the upstream diverter strip 18e, the Karman vortex generated by the downstream diverter strips 18f and 18g is reduced, or Or generation | occurrence | production is inhibited and the fluid noise level generate | occur | produced from the three diverter strips 18e, 18f, 18g whole can be reduced by this.

[Third Embodiment]
FIG. 7 is a view showing a third embodiment of the lightning arrester according to the present invention.
In the noise suppression structure C ′ of the lightning arrester C according to the third embodiment, for example, four diverter strips 18 which are a plurality of lightning arrester members provided on the surface of the wind turbine blade 9 constitute a group G3. These groups G3 are arranged in a plurality along the longitudinal direction of the wind turbine blade 9. Each group G3 is arranged near the front edge of the wind turbine blade 9.

  The plurality of diverter strips 18h, 18i, 18j, and 18k in each group G3 have the same disk shape (button shape), but have different sizes or different shapes as in the second embodiment. It may be allowed. For example, S2 <S1 <S3 is set so that the installation intervals S1, S2, and S3 of the diverter strips 18h to 18k are unequal.

  In the case of such a noise suppression structure C ′, as with the noise suppression structure A ′ in the first embodiment, the airflow downstream of the diverter strip 18 h on the upstream side with respect to the airflow flowing on the surface of the wind turbine blade 9. Therefore, Karman vortices that are alternately generated at equal intervals on the downstream side of the diverter strip 18h on the upstream side are likely to be disrupted. For this reason, it can contribute to reducing the fluid noise level resulting from Karman vortex.

[Fourth Embodiment]
FIGS. 8A and 8B are views showing a fourth embodiment of the lightning arrester according to the present invention.
In the noise suppression structure D ′ and D ″ of the lightning arrester D in the fourth embodiment, the shape of the diverter strip 18 is asymmetrical with respect to the flow direction of the airflow. For example, in the noise suppression structure D ′ shown in FIG. 8A, the diverter strip 18m is formed in an elliptical shape in a plan view, and its long axis is arranged so as to be inclined with respect to the flow direction of the airflow. Further, in the noise suppression structure D ″ shown in FIG. 8B, the diverter strip 18n has a disc shape (button shape) partly cut out in plan view, and the cut line 18n ′ is the diverter. -It arrange | positions so that it may incline with respect to the flow direction of the airflow, and the wake of the strip 18n. In addition, there is no limitation in these shapes, Other shapes may be sufficient as long as it is asymmetrical.

  In this way, if the shape of the diverter strips 18m and 18n is asymmetrical with respect to the flow direction of the airflow, a speed difference is generated in the airflow flowing on both sides of the diverter strips 18m and 18n. The airflow downstream of the strips 18m and 18n becomes uneven, and Karman vortices cannot be generated. For this reason, the fluid noise resulting from generation | occurrence | production of Karman vortex can be suppressed.

[Fifth Embodiment]
FIGS. 9A and 9B are views showing a fifth embodiment of the lightning arrester according to the present invention.
In the noise suppression structure E ′ and E ″ of the lightning arrester E according to the fifth embodiment, the shape of the diverter strips 18o and 18p is streamlined with respect to the flow direction of the airflow. For example, in the noise suppression structure E ′ shown in FIG. 9A, the diverter strip 18o is formed in a water-drop streamline shape in plan view. Further, in the noise suppression structure E ″ shown in FIG. 9B, the diverter strip 18p is formed in a streamline shape with a rounded (slope) on the shoulder portion in a side view.

  In this way, if the shape of the diverter strips 18o, 18p is made a streamline shape with respect to the flow direction of the airflow, the airflow downstream of the diverter strips 18o, 18p is adjusted to prevent the generation of Karman vortices, Fluid noise can be suppressed.

[Sixth Embodiment]
FIG. 10 is an enlarged perspective view of the wind turbine blade 9 showing the sixth embodiment of the lightning arrester according to the present invention. In the lightning arrester F in the sixth embodiment, the noise suppression structure F ′ is applied only in a range from the blade tip of the wind turbine blade 9 to 20% of the blade length. The configuration of the noise suppression structure F ′ may be any of the noise suppression structures A ′ to E ′ of the first to fifth embodiments described above. Moreover, the noise suppression structures A ′ to E ′ may be combined.

  A plurality of diverter strips 18q are arranged at a predetermined interval and number in a portion other than the 20% range, and are not particularly arranged to suppress the generation of Karman vortices. For example, in FIG. 10, these diverter strips 18 are arranged in a line along the front edge of the wind turbine blade 9.

  The noise level emitted from the wind turbine blade 9 increases in proportion to the sixth power of the radius of the wind turbine blade. For this reason, as shown in FIG. 11, the generation level of fluid noise becomes the highest in the range from the blade tip to 20% of the blade length. For this reason, for example, when the length of the wind turbine blade 9 is 50 m, the noise suppression structure F ′ (A ′ to E ′) is provided only to a length of 20% from the blade tip, that is, a range of 10 m on the tip side. By applying, it is possible to relatively freely arrange the diverter strip 18q and the like in other parts, thereby improving the lightning resistance performance without increasing the fluid noise level.

  And by providing the wind power generation device 1 with the lightning protection devices A to F of the above embodiments, the wind power generation device without increasing the fluid noise level due to the diverter strip 18 provided on the surface of the wind turbine blade 9 with a simple structure. The lightning resistance performance of 1 can be improved.

  In addition, embodiment of this invention is not limited only to the above-mentioned 1st-6th embodiment. For example, the first to sixth embodiments may be combined. Further, the lightning arrester according to the present invention is not limited to the wind turbine rotor blades of the wind power generator, but can be applied to other types of wind turbine rotor blades.

DESCRIPTION OF SYMBOLS 1 Wind power generator 6 Rotor head 9 Windmill blade 10 Windmill rotor 11 Generator 17 Receptor (lightning protection member / grounding member)
18 Divertor strip (lightning protection)
18e Divertor strips 18f and 18g on the upstream side with respect to the flow direction of the air flow Diverter strips A, B, C, D, E, and F on the downstream side with respect to the flow direction of the air flow , C ′, D ′, D ″, E ′, F ′ Noise suppression structure S, S1, S2, S3 Installation interval of divertor strip

Claims (10)

A lightning arrester for a windmill rotor blade, in which a lightning arresting member projects from the surface of the windmill blade extending in a radial direction from a rotor head rotatably supported,
A lightning arrester for a wind turbine rotor blade having a noise suppression structure that suppresses generation of Karman vortices on the downstream side of the lightning arrester against airflow flowing on the surface of the windmill blade during rotation of the windmill rotor blade apparatus.   The noise suppression structure is an array structure in which a plurality of lightning protection members are arranged in a meandering direction along the flow direction of the airflow on the surface of the wind turbine blade, and the spacing between the plurality of lightning protection members is determined by the Karman vortex. The lightning arrester for a wind turbine rotor blade according to claim 1, wherein the lightning arrester is adapted to a generation interval of   The wind turbine rotation according to claim 2, wherein, among the plurality of lightning arresting members, the size of the lightning arresting member on the downstream side with respect to the flow direction of the airflow is made smaller than that of the lightning arresting member on the upstream side. Wing lightning arrester.   The lightning arrester for a wind turbine rotor blade according to claim 2 or 3, wherein the plurality of lightning arresting members are installed at unequal intervals.   2. The lightning arrester for a wind turbine rotor according to claim 1, wherein the noise suppression structure is a structure in which the shape of the lightning protection member is asymmetrical with respect to a flow direction of the airflow.   2. The lightning arrester for a wind turbine rotor blade according to claim 1, wherein the noise suppression structure is a structure in which a shape of the lightning protection member is a streamline shape with respect to a flow direction of the airflow.   The lightning arrester of the wind turbine rotor blade according to any one of claims 1 to 6, wherein the lightning arrester member is provided in the vicinity of a front edge portion of the wind turbine blade.   The said lightning protection member is a diverter strip which makes a lightning current flow along the surface of the said windmill blade, and guides it to the earthing member provided in the said windmill blade. Lightning arrester for windmill rotor blades.   The lightning arrester for a wind turbine rotor blade according to any one of claims 1 to 8, wherein the noise suppression structure is applied to a range from a blade tip of the wind turbine blade to 20% of a blade length.   A wind turbine generator comprising the lightning arrester for a wind turbine rotor blade according to any one of claims 1 to 9.

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