JP2018173087A - Blade for wind power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blade for a wind power generator capable of restricting lightening against a location of the blade other than its lightening receiving part on the basis of a concept that lightning itself near items to be protected is restricted so as to protect them.SOLUTION: This invention relates to a blade 5 used at a wind power generator that is constituted in such a way that an inner electrode 6 formed by electric conductive material is inserted into the blade and fixed there, a surface of the blade at its extremity end is provided with an induction electrode 7 that is formed by electric conductive material and electrically connected to the inner electrode, there is provided an outer electrode 8 formed by the electric conductive material at the surface of the blade in a range from a location spaced apart from the induction electrode to a location near the base part of the blade, there is provided an insulation layer between the outer electrode and the inner electrode and between the outer electrode and the induction electrode so as to insulate them electrically and further the inner electrode is connected to the ground.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a blade used in a wind turbine generator, and more particularly, to a blade for a wind turbine generator that suppresses damage due to lightning.

Generally, wind power generation energy is known as one of renewable energies.
The wind power generator for generating wind power energy includes a high column, a nacelle mounted on the upper part of the column and including a generator, and a plurality of blades that are mounted on the nacelle and rotationally drive the generator. It has.

  This wind power generator is configured to generate power by driving the generator when the blades are rotated by wind.

In such a wind power generator, in order to receive the wind efficiently, the support is raised and the installation position of the blade is raised.
In order to increase the amount of power generation, the blades are also made longer and longer.

By the way, in a wind power generator installed so as to extend to a high place in this way, lightning strikes easily.
When lightning strikes the blade, the blade is damaged by the lightning strike, and power generation cannot be performed.

  Conventionally, for example, a countermeasure technique as disclosed in Patent Document 1 has been proposed for such a problem.

  In this technology, a lightning receiving portion made of metal is provided at the tip of a blade, and a grounding wire electrically connected to the lightning receiving portion is grounded to the ground through the inside of the blade.

  When a lightning strike toward the wind turbine generator occurs, the lightning strike is guided to the lightning receiving part, and the lightning strike passes through the blade by flowing the lightning strike from the lightning receiving part to the ground via the ground line. This prevents the blade itself from being damaged.

JP 2012-246812 A

  By the way, in the conventional technique described above, the following problems to be improved still remain.

That is, in a state where the rotation of the blade is stopped, the lightning receiving portion is in a fixed position.
When a lightning strike occurs toward the blade in this state, the lightning strike can be guided to a lightning receiving portion at a fixed position, and the lightning strike can be emitted to the ground through a ground line.

  However, when the blade is rotating, it is assumed that a lightning strike toward the blade cannot be guided to the lightning receiving portion because the linear velocity at the tip, that is, the moving speed of the lightning receiving portion is high.

  In this way, if a lightning strike toward the blade cannot be guided to the light receiving section, a lightning strike will occur on the more proximal side of the blade, and the lightning strike will pass through the blade itself and through the nacelle and struts to the ground. Released.

  Then, the lightning that passes through the blade damages the blade, or when the electric shock passes through the nacelle, the oil injected into the generator, speed reducer, or bearing incorporated in the nacelle It is assumed that the fire will ignite and cause a fire.

  Such problems are based on the idea that lightning is guided to a place other than the object to be protected, such as an important facility or equipment, thereby protecting the object to be protected from lightning strikes caused by the lightning strike. This is due to the fact that

  Therefore, the present invention is based on the idea of suppressing lightning strikes in the vicinity of the protected body and protecting them, and has a structure capable of suppressing lightning strikes to parts other than the lightning receiving portion of the blade. Providing is a problem to be solved.

  In order to solve the above-described problems, the blade for wind power generator according to the present invention has an internal electrode formed of a conductive material inserted into the blade, and the conductive material is formed on the surface of the tip of the blade. And an induction electrode electrically connected to the internal electrode is provided, and is formed of a conductive material on a surface of the blade from a portion spaced from the induction electrode to a vicinity of the base of the blade. An external electrode is provided, an insulating layer is provided between the external electrode, the internal electrode, and the induction electrode to electrically insulate the external electrode, and the internal electrode is grounded. Yes.

Here, when the phenomenon of lightning strikes is observed in detail, in the case of a general lightning strike (summer lightning) that occurs in the summer, when the thundercloud matures, the step trader approaches the ground while selecting a place where the atmosphere is likely to be discharged from the thundercloud.
When the stepreader is at a certain distance from the ground, a weak current upward streamer (greeting discharge) extends from the ground, a building (lightning rod), a tree, or the like toward the stepreader.
When this streamer and steppeda are coupled, a large current (feedback current) flows between the thundercloud and the ground through the path. This is a lightning phenomenon.

  In the present invention, by using the blade having the above-described configuration, the above-described upward streamer is less likely to occur in a portion other than the blade tip.

  That is, the blade has an induction electrode provided on the tip surface thereof electrically connected to an internal electrode mounted inside the blade, and an external electrode provided on the base side surface of the blade, It is electrically insulated from the induction electrode and the internal electrode, and the internal electrode is grounded.

  Therefore, for example, when a thundercloud in which a negative charge is distributed on the cloud bottom approaches, the opposite charge (plus charge) is distributed on the surface of the earth and is attracted to the negative charge on the cloud bottom, so that the internal electrode and the induction electrode Also, positive charges will be collected.

Then, the external electrode disposed via the insulator is negatively charged by the action of the capacitor.
This action makes it difficult for upward streamers to occur on the base side excluding the tip of the blade and its surroundings, suppresses lightning strikes to the base side of the blade, and sends lightning to the induction electrode at the blade tip. Can be guided.

  And since the lightning strike of the thunderbolt is emitted to the ground through the internal electrode to which the induction electrode is electrically connected, it is possible to suppress damage and ignition of the equipment in the blade or nacelle.

  As the internal electrode, a strength member in the blade provided to support the blade can be used.

  The induction electrode and the external electrode can be formed of a coating film made of a conductive paint, and can be formed of a metal plate or a metal mesh.

  Furthermore, the induction electrode and the external electrode can be formed of a carbon fiber sheet or a carbon fiber mesh.

  As the insulating layer, an air layer can be formed in the blade, and a spacer made of an electrically insulating material is interposed between the external electrode, the internal electrode, and the induction electrode. Can be configured.

  The spacer can be a fired body of an inorganic material.

According to the blade for wind power generator of the present invention, the internal electrode provided inside the blade and grounded, and provided on the outer surface other than the tip of the blade in a state of being electrically insulated from the internal electrode. The external electrode is charged with a negative charge when approaching a thundercloud, and an induction electrode electrically connected to the internal electrode is provided on the surface of the tip of the blade so as to have a positive charge. Can do.
As a result, it is possible to suppress the occurrence of the above-described upward streamer at a portion other than the tip of the blade to suppress a lightning strike, guide the lightning strike to the tip of the blade, and discharge the lightning strike to the ground.

It is a front view which shows the wind power generator to which the 1st Embodiment of this invention is applied. It is a side view which shows the wind power generator to which the 1st Embodiment of this invention is applied. It is an enlarged side view which shows the 1st Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The 1st Embodiment of this invention is shown and it is an enlarged front view of a braid | blade. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view illustrating a first embodiment of the present invention and enlarging a blade. It is a figure explaining the principle that the blade surface (external electrode) which concerns on the 1st Embodiment of this invention is tinged with a negative charge. It is a figure explaining the principle that the blade surface (external electrode) which concerns on the 1st Embodiment of this invention is tinged with a negative charge. It is a figure explaining the principle that the blade surface (external electrode) which concerns on the 1st Embodiment of this invention is tinged with a negative charge.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a wind turbine generator to which the present embodiment is applied. The wind turbine generator 1 includes a column 2 standing on the ground G and a nacelle 3 mounted on the top of the column 2. As shown in FIG. 3, three blades 5 according to the present embodiment are mounted on the boss 4 disposed inside the nacelle 3.

  Each blade 5 is connected to a generator (not shown) mounted inside the nacelle 3 through the boss 4, and the blade 5 is rotated by receiving wind. Thus, the generator is driven to generate power.

  The main body of the blade 5 according to the present embodiment is formed of an electrically insulating material, and an internal electrode 6 formed of a conductive material is inserted therein as shown in FIG.

An induction electrode 7 made of a conductive material is integrally provided on the outer peripheral surface of the tip of the blade 5.
The induction electrode 7 is integrated with the internal electrode 6 inside and electrically connected to each other.

  On the other hand, on the surface of the blade 5, an external electrode 8 made of a conductive material is provided in a range from a position spaced a predetermined distance from the induction electrode 7 toward the base side to the vicinity of the base part.

  Since the main body of the blade 5 is formed of an electrically insulating material, the main body portion of the blade 5 is interposed between the external electrode 8 and the internal electrode 6 and the induction electrode 7 so as to form an insulating layer. Nine.

  Further, the internal electrode 6 is electrically grounded through other components of the wind power generator 1.

  Further, as shown in FIG. 5, the external electrode 8 is formed on the base side of the blade 5 (on the side of the joint portion with the nacelle 3) such that the distance from other metal parts is a certain distance or more. ing.

  The internal electrode 6 is inserted as a structural member over the entire length of the blade 5, and supports the blade 5 from the inside to ensure the strength of the blade 5.

  In the wind turbine generator 1 having the blade 5 of the present embodiment configured as described above, the ground G is negatively charged in fine weather, and accordingly, the internal electrode 6 and the induction electrode 7 also has a negative charge as shown in FIG.

  Further, since the external electrode 8 is insulated from the internal electrode 6 and the induction electrode 7, it is not charged.

  Then, as shown in FIG. 7, when a thundercloud C with a negative charge distributed near the cloud bottom approaches and an electric field is applied to the thundercloud C and the ground G, a positive charge is distributed on the surface of the ground G, The internal electrode 6 and the induction electrode 7 which are in conduction with the ground G are also charged with a positive charge.

  Further, the inner surface of the external electrode 8 is negatively charged due to the positive charge of the internal electrode 6, and the outer surface is positively charged as shown in FIG.

  When the thundercloud C further approaches and the electric field changes, the positive charge on the surface of the external electrode 8 is neutralized by aerosol or the like. As shown in FIG. 8, the positive charge of the internal electrode and the action of the capacitor Thus, the external electrode 8 is negatively charged.

  As a result, the upward streamer in the blade 5 and its surroundings is generated from the induction electrode 7 provided at the tip of the blade 5, and a lightning strike is guided to the induction electrode 7. 6 can be diffused to the ground G.

  On the other hand, in the state where no lightning strikes on the induction electrode 7, the base end side of the blade 5 is negatively charged by the external electrode 8. Therefore, the upward streamer from the base end portion of the blade 5 is used. By preventing the occurrence of lightning, lightning strikes to the base end are suppressed.

  Therefore, the lightning strike is induced to the induction electrode 7 and diffused to the ground G through the internal electrode 6.

  As a result, destruction of the blade 5 is prevented, or ignition of equipment in the nacelle 3 is prevented.

The above-described operation in the present embodiment is maintained even when the blade 5 is rotating.
Therefore, lightning can be guided to a safe position regardless of whether the blade 5 is stopped or rotating.

  As a result, the soundness of the blade 5 and, consequently, the soundness of the wind turbine generator 1 can be significantly increased.

  In addition, as the conductive material, for example, a metal plate such as aluminum or stainless steel, a metal foil, or a mesh thereof is used, and the induction electrode 7 and the external electrode 8 are attached by sticking them to the surface of the blade 5. It can also be formed.

  Alternatively, the induction electrode 7 and the external electrode 8 can be formed by fixing the metal on the surface of the blade 5 by vapor deposition.

  Alternatively, a conductive paint can be used as the conductive material, and the conductive paint can be applied to the surface of the blade 5 to form a conductive coating film, thereby forming the induction electrode 7 and the external electrode 8. .

  Furthermore, the induction electrode 7 and the external electrode 8 can be formed of a sheet or mesh made of carbon fiber.

  When the induction electrode 7 and the external electrode 8 are formed using a mesh as described above, not only can the weight of these electrodes be reduced, but also when the blade 5 is moved relative to the air. Furthermore, by forming innumerable air vortices on the blade 5 surface, the flow resistance can be reduced and the rotational efficiency of the blade 5 can be increased.

  Moreover, when using the said mesh, it is also possible to apply | coat the electroconductive coating material mentioned above on this mesh, and to make it a 2 layer structure.

On the other hand, it is also possible to form a hollow portion in the blade 5 and form the insulating layer 9 using an air layer in the hollow portion.
This is suitable for reducing the weight of the blade 5.

  The insulating layer 9 can be formed by interposing a spacer made of an electrically insulating material between the external electrode 8 and the internal electrode 6 and the induction electrode 7.

  For example, a fired body of an inorganic material can be used as the electrical insulating material.

DESCRIPTION OF SYMBOLS 1 Wind power generator 2 Prop 3 Nacelle 4 Boss 5 Blade 6 Internal electrode 7 Induction electrode 8 External electrode 9 Insulating layer C Thundercloud G Ground

Claims (10)

  A blade used in a wind turbine generator, wherein an internal electrode formed of a conductive material is inserted therein, is formed of a conductive material on a tip surface of the blade, and is electrically connected to the internal electrode. A connected induction electrode is provided, and on the surface of the blade, an external electrode formed of a conductive material is provided in a range from a portion spaced from the induction electrode to the vicinity of the base of the blade. A blade for a wind turbine generator, wherein an insulating layer for electrically insulating them is provided between the internal electrode and the induction electrode, and the internal electrode is grounded.   The blade for wind power generator according to claim 1, wherein the internal electrode is a strength member that supports the blade.   The blade for wind power generator according to claim 1, wherein at least one of the induction electrode and the external electrode is a coating film made of a conductive paint.   The blade for wind power generator according to claim 1, wherein at least one of the induction electrode and the external electrode is a metal plate.   The blade for wind power generator according to claim 1, wherein at least one of the induction electrode and the external electrode is a metal mesh.   The blade for wind power generator according to claim 1, wherein at least one of the induction electrode and the external electrode is a carbon fiber sheet.   The blade for wind power generator according to claim 1, wherein at least one of the induction electrode and the external electrode is a carbon fiber mesh.   The blade for wind power generator according to any one of claims 1 to 7, wherein the insulating layer is an air layer formed in the blade.   The wind power according to any one of claims 1 to 7, wherein the insulating layer is a spacer made of an electrically insulating material interposed between the external electrode, the internal electrode, and the induction electrode. Blade for power generator. The blade for wind power generator according to claim 9, wherein the spacer is a fired body of an inorganic material.