TWI820287B - Lightning protection grounding device and lightning protection grounding method - Google Patents

Abstract

The invention provides a lightning protection grounding device and a lightning protection grounding method. When a lightning strike occurs in a wind turbine that shares lightning protection grounding and electrical grounding, the lightning protection grounding and electrical grounding can be disconnected, thereby protecting the electrical equipment of the wind turbine generator. The lightning protection grounding device of the present invention is a lightning protection grounding device used for lightning protection of wind turbines, and is configured to include: electrical grounding to ground the electrical equipment that controls the wind turbine; and lightning protection grounding to prevent lightning flowing when lightning strikes the wind turbine. The ground is grounded by means of current discharge; and at least one or more ring coils connect the electrical ground and the lightning protection ground; the ring coil is cut off by electromagnetic force, thereby blocking the lightning protection ground and the electrical ground. The electromagnetic force is It is generated by the current flowing from the lightning current flowing to the lightning protection ground side when lightning strikes.

Description

Lightning protection grounding device and lightning protection grounding method

The invention relates to a lightning protection grounding device and a lightning protection grounding method, which discharge the lightning current flowing when lightning strikes a wind turbine.

In recent years, the demand for wind turbines has increased due to the rising demand for renewable energy (energy). However, wind turbines are susceptible to lightning damage due to their unique shape. That is, they are built at a height of about 60 [m] to 100 [m] in a location with a good field of view and support a steel tower. Or the blade itself is formed into a long strip in the height direction. Therefore, the wind turbine is equipped with a lightning protection ground for lightning strikes.

As a lightning protection system for a wind turbine, for example, a wind turbine protection system described in Patent Document 1 is known. The protection system includes: a conductor ring, which is installed on the blade; and a zinc oxide lightning protection element, which is installed opposite the conductor ring in the rotor case for accommodating the generator; the zinc oxide lightning protection element is composed of It is arranged with a gap from the conductor ring to prevent an increase in induced overvoltage generated in the electronic parts of the wind turbine generator.

Patent Document 2 describes a wind turbine that protects the power generation equipment of the wind turbine from lightning damage. The wind turbine includes: an insulating part provided in a receiving box of the generator; a lightning rod provided on the insulating part; and a wire connecting the lightning rod to the grounding part; passing the current generated by the lightning received from the lightning rod to the ground side via the wire. Grounded to protect the generator inside the containment box from lightning damage.

Patent Document 3 describes a wind turbine that protects a frequency conversion device of the wind turbine from lightning damage. The wind turbine includes: an insulator located between the frequency conversion device and the base; and a wire connecting the frequency conversion device to the ground; when the current generated by lightning flows in the earth, the ground wire of the frequency conversion device is prevented from being connected to the ground. A loop circuit is formed between the frequency conversion devices. [Prior art documents] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-265938 [Patent Document 2] Japanese Patent Application Publication No. 2004-225660 [Patent Document 3] Japanese Patent No. 6019660

[Problem to be solved by the invention]

In the design standards of wind turbines, the ground resistance is set to 10 [Ω] or less. Furthermore, according to this standard, lightning protection grounding and electrical grounding used in electrical equipment such as power generation devices inside wind turbines and communication equipment are often shared without distinction. When lightning protection grounding and electrical grounding are shared in a wind turbine, there is a concern that excessive voltage and current are induced in electrical equipment due to lightning strike current generated when lightning strikes, and the electrical equipment may be damaged. However, the documents of Patent Document 1 to Patent Document 3 do not mention sharing a lightning protection ground with an electrical ground to receive protection of electrical equipment during a lightning strike.

An object of the present invention is to provide a lightning protection grounding device and a lightning protection grounding method that can disconnect the lightning protection grounding and the electrical grounding when a lightning strikes a wind turbine that shares the lightning protection grounding and the electrical grounding, thereby protecting the electrical equipment of the wind turbine generator. [Means to solve the problem]

The invention is a lightning protection grounding device, used for lightning protection of wind turbines, and includes: electrical grounding to ground the electrical equipment that controls the wind turbine; lightning protection grounding to ground lightning flowing when lightning strikes the wind turbine. Grounding by means of current discharge; and at least one loop coil to connect the electrical ground and the lightning protection ground; the loop coil is cut off by electromagnetic force, thereby connecting the lightning protection ground Interrupted from the electrical ground, the electromagnetic force is generated by a current flowing from a lightning current flowing to the lightning protection ground side when lightning strikes.

According to the present invention, when a lightning strike occurs in a wind turbine that shares a lightning protection ground and an electrical ground, the current generated by the lightning strike flows from the lightning protection ground side to the electrical ground side in the toroidal coil electrically connecting the lightning protection ground and the electrical ground. At this time, an electromagnetic force acts on the toroidal coil in the direction of cutting the toroidal coil due to the sudden inflow of current, so that the toroidal coil is cut off. By cutting off the toroidal coil, the electrical equipment of the wind turbine is protected from lightning current damage.

The present invention may be configured to include a first annular portion on the lightning protection ground side and below the ground surface side, and the first annular portion is formed into an annular shape substantially parallel to the ground surface.

According to the present invention, by providing the lightning protection ground formed in a ring shape on the ground surface side, the lightning current can be spread radially on the ground surface in accordance with the characteristics of lightning.

In the present invention, the first annular portion may include a plurality of first electrode portions arranged radially.

According to the present invention, since the first annular portion includes a plurality of first electrode portions arranged radially, the lightning current can be easily spread radially on the ground surface.

In the present invention, the first electrode part may include a plurality of needle-shaped bodies, and the plurality of needle-shaped bodies may be formed to protrude in a direction orthogonal to the axial direction of the first electrode part.

According to the present invention, since the first electrode part includes a plurality of needle-shaped bodies, lightning current can be spread more easily on the ground surface.

The present invention may also be configured such that the electrical ground is installed underground and is spaced a predetermined distance below the lightning protection ground, and includes a second annular portion formed into an annular shape substantially parallel to the ground surface or is provided approximately at At least one or more second electrode portions in the vertical direction.

According to the present invention, by installing the electrical ground underground and at a predetermined distance below the lightning protection ground, lightning current spread by the lightning protection ground on the ground surface side is prevented from flowing to the electrical ground side, thereby protecting electrical equipment. In addition, by including the second annular portion or the second electrode portion, the electrical grounding can be designed according to the construction method of the base or the characteristics of the foundation.

In the present invention, the second electrode portion may be connected to steel bars provided in a plurality of concrete piles of the wind turbine generator.

According to the invention, the steel bars forming the concrete piles supporting the foundations of the wind turbines can be used as earth bars.

The present invention may also be configured to be connected to a plurality of steel pipe piles provided in the wind turbine.

According to the present invention, the steel pipe piles supporting the foundation of the wind turbine can be used as ground rods.

The present invention may also be configured to be provided in a boring hole formed in the installation of the wind turbine.

According to the present invention, it is possible to effectively utilize the drilling holes formed in the foundation survey before installing the wind turbine.

The present invention may also be configured such that the lightning protection grounding is provided at a depth of 0.6 to 0.8 meters from the ground surface.

According to the present invention, lightning protection grounding can spread lightning current at a shallow position from the ground surface.

The present invention may also be configured such that the electrical ground is provided at a depth of 3 to 5 meters from the ground surface.

According to the present invention, lightning current spread by lightning protection grounding on the ground surface side is prevented from reaching the electrical ground and being transferred to electrical equipment.

The invention is a lightning protection grounding method, used for lightning protection of wind turbines, and includes the following steps: grounding the electrical equipment that controls the wind turbine through electrical grounding; and grounding the electrical equipment that flows when lightning strikes the wind turbine. The lightning current discharge method is grounded by lightning protection grounding; using at least one or more loop coils to connect the electrical ground and the lightning protection ground; and causing the loop coil to be cut off by electromagnetic force, thereby all The lightning protection ground is blocked from the electrical ground, and the electromagnetic force is generated by a current flowing from a lightning current flowing to the lightning protection ground side when a lightning strikes.

According to the present invention, when a lightning strikes a wind turbine in which a lightning protection ground and an electrical ground are shared, the loop coil is cut off, and the loop coil that electrically connects the lightning protection ground and the electrical ground is blocked from the lightning protection ground side. Electric current, which can protect the electrical equipment of wind turbines from current damage caused by lightning. [Effects of the invention]

According to the present invention, when a lightning strike occurs in a wind turbine that shares lightning protection grounding and electrical grounding, the lightning protection grounding and electrical grounding can be disconnected, thereby protecting the electrical equipment of the wind turbine generator.

Hereinafter, the lightning protection grounding device S according to the embodiment of the present invention will be described.

As shown in FIG. 1 , the wind turbine 100 includes: a windmill 20 that can rotate freely; a windmill tower 1 that supports the windmill 20 ; and a base 2 that supports the windmill tower 1 . The wind turbine tower 1 is, for example, a cylindrical steel tower formed in a cross-section that becomes smaller toward the top. At the base end of the windmill tower 1, a base 2 formed of concrete is provided. The base 2 is installed deep into the ground below the ground surface E. The base 2 is formed in a rotationally symmetrical shape concentric with the wind turbine tower 1 such as a circle or a polygon in a plan view, for example.

A windmill 20 is rotatably supported on an upper end of the windmill tower 1 . The windmill 20 includes a plurality of blades 21 evenly arranged in a radial shape with a hub 20A as the center when viewed from the front. The cross section of each blade 21 in the transversal direction is formed into a wing cross-sectional shape. Each blade 21 is given an angle of attack relative to the hub 20A. Thereby, when each blade 21 receives a head wind, a force is exerted in a direction orthogonal to the wind direction, causing the windmill 20 to rotate in a predetermined direction. The rotation shaft 22 of the windmill 20 is connected to the hub 20A. The shaft of the generator 23 is connected to the rotating shaft 22 . The generator 23 generates electricity by generating an induced voltage using the rotation of the windmill 20 .

As shown in FIG. 2 , the lightning protection grounding device S is a device used for lightning protection applied to the wind turbine 100 . The lightning protection grounding device S includes: lightning protection grounding 3, which is grounded in a manner to discharge the lightning current flowing when lightning strikes the wind turbine 100; electrical grounding 5, which is used to ground the electrical equipment of the wind turbine 100; and at least one ring of more than one ring. The coil 7 electrically connects the electrical ground 5 and the lightning protection ground 3 .

The lightning protection ground 3 is electrically connected to the underground electrode of the windmill tower 1 . The lightning protection ground 3 is installed underground with the earth as a reference potential point.

The lightning protection ground 3 is ideally installed underground at a depth close to the ground surface E. The lightning protection ground 3 is provided, for example, at a depth of approximately 0.6 [m] to 0.8 [m] from the ground surface E. The lightning protection ground 3 is formed in a ring shape when viewed from above, for example. The detailed configuration such as the shape of the lightning protection ground 3 will be described later. The lightning protection ground 3 and the wind turbine tower 1 are electrically connected by a wire 3A made of a conductor such as copper.

The lead wire 3A is appropriately bent according to the connection state or the shape of the wiring target part. Thereby, the lightning protection ground 3 is configured to discharge the lightning surge current flowing in the wind turbine tower 1 to the earth side when lightning strikes the wind turbine 100 . A lightning protection grounding terminal 4 made of copper and formed into a rectangular plate-shaped body is provided at the connection portion between the conductor 3A and the toroidal coil 7 . The lightning protection grounding terminal 4 is a connection terminal to which the ends of the conductor 3A and the like are electrically connected. The lightning protection grounding terminal 4 is installed on the installation object in an insulated manner.

The electrical ground 5 is an underground electrode and is connected to electrical equipment (not shown) such as a control device that controls the generator 23 of the windmill tower 1 or a communication device. The electrical ground 5 is provided underground with the earth as a reference potential point. The electrical ground 5 is ideally separated from the lightning protection ground 3 so that no current discharged from the lightning protection ground 3 is allowed to flow in. The electrical ground 5 is installed underground and is spaced a predetermined distance below the lightning protection ground 3 .

The electrical ground 5 is provided at a depth of approximately 3 [m] to 5 [m] from the ground surface E, for example. For example, the electrical ground 5 is formed in a ring shape concentric with the wind turbine tower 1 when viewed from above. The detailed structure such as the shape of the electrical ground 5 will be described later. The electrical ground 5 and the electrical equipment are electrically connected by a conductor 5A formed of a conductor such as copper.

The conductive wire 5A is appropriately bent according to the connection state or the shape of the wiring target part. Thereby, the electrical ground 5 is configured to discharge excess current flowing in the electrical equipment to the earth side. An electrical grounding terminal 6 made of copper and formed into a rectangular plate-shaped body is provided at a connection portion between the conductor 5A and the toroid 7 . The electrical grounding terminal 6 is a connection terminal to which the end of the lead wire 5A and the like is electrically connected. The electrical ground terminal 6 is attached to the installation object in an insulated manner.

As shown in FIGS. 3 and 4 , the toroidal coil 7 electrically connects the lightning protection grounding terminal 4 and the electrical grounding terminal 6 . The loop coil 7 is formed of, for example, a copper conductive wire (IV wire) having a predetermined cross-sectional area of 22 [mm ² ] or less (for example, 14 [mm ² ]). The loop coil 7 includes, for example, a pair of straight portions 7A and 7B that are electrically connected to the lightning protection grounding terminal 4 and the electrical grounding terminal 6; and an annular ring portion 7C that electrically connects the pair of straight portions 7A and 7B. connection.

The pair of straight portions 7A and 7B stand upward and are arranged to face each other so that their axial directions are parallel. The pair of linear portions 7A and 7B can also be arranged so that the axial direction becomes the horizontal direction. The base ends of the pair of straight portions 7A and 7B are electrically connected to the lightning protection grounding terminal 4 and the electrical grounding terminal 6 respectively. The front ends of the pair of straight portions 7A and 7B are electrically connected to the ring portion 7C. The length L of the pair of straight portions 7A and 7B is formed to be approximately 0.1 [m] to 0.2 [m].

The ring portion 7C is formed with a 1.5-turn toroidal coil having a diameter of approximately 10 [cm]. The upper part of the ring part 7C is tied with a cable tie H or the like. The ring portion 7C independently stands above the lightning protection grounding terminal 4 and the electrical grounding terminal 6 with respect to the installation object so as to form a pair of straight portions 7A and 7B. In the loop coil 7 , the arrangement relationship of the straight portions 7A and 7B or the number of turns wound around the loop portion 7C is not limited to the above-described embodiment. The electrical properties of the toroidal coil 7 will be described later.

Next, the detailed structure of the lightning protection ground 3 will be described. It is known that lightning current that penetrates into the ground spreads radially at a shallow depth from the ground surface. Therefore, the lightning protection ground 3 is formed into a shape that facilitates the spread of lightning current. In addition, lightning current has a frequency of, for example, 25 [Hz] to 1 M [Hz]. In particular, grounding design requires a design that can cope with high-frequency lightning current.

As shown in FIG. 5 , the lightning protection ground 3 includes a ring portion 3R (first ring-shaped portion) formed in a ring shape concentrically with the wind turbine tower 1 in plan view. The ring portion 3R is formed in an annular shape below the ground surface side and substantially parallel to the ground surface E. The ring portion 3R is underground and above the base 2, and is formed in an annular shape so as to surround the base 2 in plan view. The ring portion 3R is formed to have a radius larger than the radial end portion of the base 2 by about 0.5 [m] to 2 [m], for example.

The ring portion 3R and the surface of the wind turbine tower 1 are electrically connected by a wire 3A. The ring portion 3R discharges the lightning surge current flowing on the surface of the wind turbine tower 1 underground. In the ring portion 3R, four discharge cords 3S (first electrode portions) are provided so as to protrude radially outward evenly in a plan view. The number of discharge cords 3S can not only be four, but can also be appropriately increased or decreased according to the capacitance of the ground corresponding to the lightning current.

The discharge cord 3S is provided so as to be arranged in a horizontal plane. The discharge cord 3S is an underground electrode made of metal and formed into a rod shape. The ring portion 3R is electrically connected to the base ends of the plurality of discharge cords 3S. The discharge cord 3S is installed so that the lightning surge current flowing in the ring portion 3R is further diffused underground and discharged.

As shown in FIG. 6 , the discharge cable 3S may also be a needle electrode provided with a plurality of needle-shaped bodies 3N. The needle-shaped body 3N is formed to protrude radially in a direction orthogonal to the axial direction P of the discharge cord 3S. By forming the plurality of needle-shaped bodies 3N in the discharge cord 3S, discharge is performed from the tip portions of each of the plurality of needle-shaped bodies 3N in response to lightning strikes. Therefore, the discharge cord 3S formed with a plurality of needle-shaped bodies 3N has a smaller surge impedance than the discharge cord 3S without the needle-shaped bodies 3N.

Next, the detailed structure of the electrical ground 5 will be described.

As shown in FIG. 7 , the electrical ground 5 includes a ring portion 5R (second ring-shaped portion) formed in a ring shape concentric with the wind turbine tower 1 in plan view. The ring portion 5R is formed in an annular shape substantially parallel to the ground surface E below the ground surface side. The ring portion 5R is underground and below the base 2, and is formed in an annular shape so as to surround the base 2 in plan view. The ring portion 5R is formed to have a radius larger than the radial end portion of the base 2 by approximately 0.5 [m] to 2 [m], for example. The ring portion 5R is electrically connected to the electrical equipment of the wind turbine tower 1 using the wire 5A. The ring portion 5R is an underground electrode that discharges excess current generated from the electrical equipment underground.

The electrical ground 5 may be formed not only by the ring part 5R but also by at least one or more ground rods 5S (second electrode parts). The ground rod 5S is an underground electrode made of metal and formed into a rod shape along the substantially vertical direction. The ground rod 5S and the conductor 5A are electrically connected by the copper wire 5D. The ground rod 5S and the lead wire 5A are connected by welding, for example.

As shown in FIGS. 8 and 9 , a plurality of concrete piles for supporting the base 2 may also be used as the ground rod 5S. Concrete piles are formed by arranging multiple steel bars in the height direction. Each concrete pile is formed as a grounding rod 5S by electrically connecting the conductor 5A to the steel bars inside the plurality of concrete piles. The steel bars may also be metal mesh. When lightning current is input into the ground using the ground rod 5S, an equipotential surface whose potential becomes lower as it goes downward is formed around the ground rod 5S.

In addition to concrete piles, the piles supporting the base 2 may also be formed of steel pipe piles. Steel pipe piles are steel piles driven into the ground. After the steel pipe piles are driven into the ground, concrete is injected inside. By electrically connecting the wire 5A to the plurality of steel pipe piles by welding, each steel pipe pile is formed as the grounding rod 5S.

As shown in FIG. 10 , the ground rod 5S can also be formed by using a drilling hole provided during ground investigation around the base 2 . When conducting a boring survey, the soil layer is core drilled to form a borehole. For example, a steel pipe is inserted into the drilled hole, and the wire 5A is electrically connected to the steel pipe. Thus, a steel pipe is formed as the ground rod 5S.

The pile-shaped electrical ground 5 using the concrete pile, steel pipe pile, and steel pipe has better discharge characteristics if it is in contact with the underground water table. The electrical ground 5 may have a ring-shaped or pile-shaped pattern as appropriate depending on the construction method of the base 2 of the wind turbine generator 100 or the properties of the foundation to be installed.

Next, the characteristics of the toroidal coil 7 will be described.

The toroidal coil 7 acts on the pair of linear portions 7A and 7B by a Lorentz force due to the current flowing to the electrical ground 5 side from the lightning current flowing to the lightning protection ground 3 side during a lightning strike.

As shown in FIG. 11 , when a lightning current flowing toward the lightning protection ground 3 side from a lightning strike flows into the loop coil 7 , currents in opposite directions flow through the pair of straight portions 7A and 7B. Normally, when a pair of mutually parallel electric wires have currents flowing in different directions, an electromagnetic force F is exerted on the pair of electric wires in a direction away from each other. Then, in the loop coil 7 , the force in the direction away from each other is instantaneously generated in the pair of linear portions 7A and 7B due to the lightning current.

In addition, currents with different directions also flow in the ring portion 7C, so the Lorentz force is instantaneously generated in the direction in which the rings are separated from each other, that is, in a radial manner. Then, when a lightning current flows into the loop coil 7, the loop portion 7C is cut off by the Lorentz force at approximately the same time, and the pair of linear portions 7A and 7B are separated from each other. In addition, an induced electromotive force induced in the opposite direction to the lightning current is generated in the ring portion 7C, thereby inhibiting the increase of the lightning current. Therefore, when a lightning current having a large current value flows instantaneously into the ring portion 7C at high frequency, the ring portion 7C becomes an inductor and may be short-circuited (short) and burned.

Therefore, the toroidal coil 7 is cut off by the force generated by the current flowing in from the lightning protection ground 3 side, thereby electrically blocking the lightning protection ground 3 and the electrical ground 5 . The electrical ground 5 is installed underground and separated from the lightning protection ground 3, and because the lightning current is spread near the ground surface by the underground lightning protection ground 3, lightning current is prevented from flowing from the underground lightning protection ground 3 to the electrical ground 5, thereby protecting the electrical ground 5. Electrical equipment.

When the lightning protection ground 3 and the electrical ground 5 are electrically disconnected, there will be no immediate obstruction to the operation of the wind turbine. However, if a potential difference occurs between the electrical equipment and the wind turbine tower 1, there is the following concern: discharge to the electrical equipment. , or discharge electricity to workers working inside the wind turbine and cause adverse effects. The loop coil 7 is monitored using, for example, a sensor or a camera, and detects the disconnection state at all times or at predetermined timing. When the loop coil 7 is detected to be disconnected, it is replaced with a new loop coil 7 .

According to the lightning protection grounding device S, when a lightning strikes a wind turbine that shares lightning protection grounding and electrical grounding, the lightning protection grounding and electrical grounding can be disconnected, thereby protecting the electrical equipment of the wind turbine generator. In addition, according to the lightning protection grounding device S, the lightning protection grounding 3 is formed into a ring shape in accordance with the characteristics of lightning current spreading underground, and a plurality of discharge cables 3S are provided in a radial pattern, thereby reducing surge impedance. In addition, according to the lightning protection grounding device S, the electrical ground 5 is provided below the lightning protection ground 3. Therefore, the lightning current spreading in the lightning protection ground 3 does not flow into the electrical ground 5, and electrical equipment can be reliably protected.

The embodiments for implementing the present invention have been described above. However, the present invention is not limited to the embodiments, and various modifications and substitutions can be made without departing from the gist of the present invention. For example, the lightning protection grounding device S can be applied not only to wind turbines, but also to tower-like structures such as communication base stations. A plurality of toroidal coils 7 may be provided, and the circuit may be set so that when the toroidal coil 7 in use is cut off, another toroidal coil 7 may be replaced for use.

1: Windmill Tower 2: base 3: Lightning protection grounding 3A, 5A: Wire 3N: needle-like body 3R: Ring part (first ring part) 3S: Discharge cord (first electrode part) 4: Lightning protection grounding terminal 5: Electrical grounding 5D: Copper wire 5R: Ring part (second ring part) 5S: Ground rod (second electrode part) 6: Terminal for electrical grounding 7:Toroidal coil 7A, 7B: Straight line part 7C: Ring part 20:Windmill 20A:wheel hub 21: blade 22:Rotation axis 23:Generator 100:Wind turbine E: Ground surface F: electromagnetic force H: Cable tie P: axis direction S: Lightning protection grounding device

FIG. 1 is a side view showing the structure of a wind turbine generator according to an embodiment of the present invention. FIG. 2 is a diagram showing the structure of a lightning protection grounding device. 3 is a front view showing the structure of a loop coil included in the lightning protection grounding device. 4 is a side view showing the structure of a loop coil included in the lightning protection grounding device. 5 is a plan view showing the structure of a lightning protection ground included in the lightning protection grounding device. FIG. 6 is a diagram showing the structure of a discharge cable provided in a lightning protection ground. 7 is a plan view showing the structure of the electrical ground included in the lightning protection grounding device. FIG. 8 is a diagram showing another structure of electrical grounding. FIG. 9 is a diagram showing the structure of a concrete pile used for electrical grounding. FIG. 10 is a diagram showing another structure of electrical grounding. FIG. 11 is a diagram showing the electromagnetic force acting on the toroidal coil.

1: Windmill Tower

3: Lightning protection grounding

3A, 5A: Wire

4: Lightning protection grounding terminal

5: Electrical grounding

6: Terminal for electrical grounding

7:Toroidal coil

E: Ground surface

S: Lightning protection grounding device

Claims (11)

A lightning protection grounding device is used for lightning protection of wind turbines and includes: electrical grounding to ground the electrical equipment controlling said wind turbine; Lightning protection grounding, grounding in a manner to discharge the lightning current flowing when lightning strikes the wind turbine; and At least one or more ring-shaped coils connect the electrical ground and the lightning protection ground; The toroidal coil is cut off by an electromagnetic force caused by a current flowing to the lightning protection ground side from a lightning strike, thereby blocking the lightning protection ground from the electrical ground. produce. The lightning protection grounding device described in item 1 of the patent application scope, wherein, The lightning protection grounding includes a first annular portion below the ground surface side, and the first annular portion is formed into an annular shape substantially parallel to the ground surface. The lightning protection grounding device described in item 2 of the patent application scope, wherein, The first annular portion includes a plurality of first electrode portions arranged radially. The lightning protection grounding device described in item 3 of the patent application scope, wherein, The first electrode part includes a plurality of needle-shaped bodies, and the plurality of needle-shaped bodies are formed to protrude in a direction orthogonal to an axial direction of the first electrode part. The lightning protection grounding device described in any one of items 2 to 4 of the patent application scope, wherein, The electrical ground is arranged underground and is spaced a predetermined distance below the lightning protection ground, and includes a second annular portion or at least one or more second electrode portions. The second annular portion is connected to the ground surface. It is formed into a substantially parallel annular shape, and the second electrode part is provided in a substantially vertical direction. The lightning protection grounding device described in item 5 of the patent application scope, wherein, The second electrode portion is connected to steel bars provided in a plurality of concrete piles of the wind turbine. The lightning protection grounding device described in item 5 of the patent application scope, wherein, The second electrode part is connected to a plurality of steel pipe piles provided in the wind turbine. The lightning protection grounding device described in item 5 of the patent application scope, wherein, The second electrode portion is provided in a drilled hole formed during installation of the wind turbine. The lightning protection grounding device described in item 5 of the patent application scope, wherein, The lightning protection grounding is located at a depth of 0.6 to 0.8 meters from the ground surface. The lightning protection grounding device described in item 5 of the patent application scope, wherein, The electrical ground is provided at a depth of 3 to 5 meters from the ground surface. A lightning protection grounding method is used for lightning protection of wind turbines and includes the following steps: Grounding the electrical equipment controlling the wind turbine by electrical grounding; Grounding through lightning protection grounding in a manner that discharges the lightning current flowing when lightning strikes the wind turbine; Connecting the electrical ground and the lightning protection ground using at least one or more loops of toroidal coils; and The lightning protection ground and the electrical ground are blocked by cutting off the toroidal coil by electromagnetic force, which is a current flowing to the lightning protection ground side from the time of lightning strike. And produce.

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