JP2003282295A - Arrester for wind turbine power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a lightning striking a blade of a wind turbine power generator by removing static charges on the blade itself to become a cause of the lightning. <P>SOLUTION: An annular or a needle-shaped metal member opposed to the lower end of the blade at a small distance apart therefrom is attached to a part positioned in a lower part of the blade of a steel tower with the wind turbine power generator mounted thereon via a support member. The charges on the blade are discharged to the metal member which approaches thereto for every rotation of the blade so as to remove the accumulated charges to become the cause of lightning. The blade is deflected rearward by receiving the wind, so that the metal member is disposed by taking account of the deflection of the blade. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention prevents a lightning strike from occurring in a wind turbine generator including a wind turbine generator having a plurality of blades rotated by wind power, and a wind turbine tower including the generator. The present invention relates to a lightning protection device.

[0002]

2. Description of the Related Art A wind turbine generator, as shown in FIG. 6, includes a nacelle 3 mounted on a bed frame 2 at the top of a wind turbine tower 1 and a rotor of a generator provided in the nacelle 3. It is equipped with a huge blade (blade) 8 with a diameter of 50 to 80 m for rotation by wind power, and the highest part reaches 100 m in the MW class, so it is a good target for lightning. . Especially the cloud base of the thundercloud is 300m
In a region where so-called winter lightning frequently occurs, which is extremely low at about 500 m, lightning strikes on the wind turbine generator frequently occur. A lightning rod 7 is planted on the upper portion of the nacelle as shown in FIG. 6, but this is not enough to prevent the blade from being hit by lightning. And if a blade is destroyed by a lightning strike, it costs about 10 million yen to repair or replace it per blade, so there is a strong desire to prevent lightning strikes or minimize damage from lightning strikes. There is.

As a means for this, it has been attempted to build a lightning protection tower near the wind turbine tower and place the entire wind turbine in a shielded space. However, when the tower height exceeds 50 m, the lightning protection tower Not only will the construction cost increase, but there is also a greater risk of lightning strikes that penetrate under the lightning tower's shielding area. Also, in the case of offshore wind power generation facilities, which are going up as a future location requirement, the installation of the lightning protection tower itself becomes a difficult problem.

Therefore, as a measure for preventing the lightning stroke, a lightning conductor 9 is laid on the blade, or a steel wire or metal net called a receptor is buried near the tip of the blade, and a ground conductor 10 is used to generate a lightning current. Although a device for guiding to the ground has been developed, since the tip of the blade is thin, it is difficult to extend a large-diameter rod for passing a large current to the tip. Therefore, when a lightning strikes the tip of the blade directly, the tip of the blade may be destroyed before the current flows to the ground through the receptor, and eventually the blade body may be destroyed.

Further, for example, Japanese Patent Laid-Open No. 2001-1239.
It is said that the installation of an early streamer launch type lightning rod as proposed in No. 34 has an advantage that protection is strengthened as compared with a normal lightning rod, but the blade tip is higher than the lightning rod installation position with rotation. In addition to being outside the protection range of the lightning rod, if so-called multiple lightning strikes at an interval of 40 msec to 50 msec occurs, it may not be possible to prevent lightning from striking the equipment to be protected because ionization will not be in time. obtain.

Further, as proposed in Japanese Patent Laid-Open No. 2000-265938, an attempt is made to provide a spark gap between the blade and the nacelle to limit the lightning current guided from the metal tip of the blade with a ZnO element or the like. However, this is a concept of how to guide the lightning current to the rotor case, and is not useful for lightning protection of the blade tip.

[0007]

By the way, the blade of a wind turbine of a wind turbine generator is charged by friction with dust and wind and snow in the air while the wind turbine is turned and rotated. With this charging, the electric field at the tip of the blade gradually increases, and creates an atmosphere that encourages the start of capture discharge even if it does not reach capture discharge for leader lightning. Therefore, it is considered that at least the lightning stroke to the blade itself can be prevented by calming the atmosphere state in advance.

When the potential at the tip of the blade is lowered, the next highest position and high current collecting effect is the lightning rod 7 installed on the nacelle, so that the discharge from the thundercloud is directed toward this lightning rod. If the blade is equipped with a receptor and a ground wire, it is possible for the receptor to discharge, but in any case it is possible to prevent direct lightning strikes to the most defenseless blade tip.

Therefore, according to the present invention, by constantly discharging the electric charge at the blade tip, which is considered to be the largest cause of lightning strikes to the wind turbine generator, and keeping the electric field that is the source of the lightning strike as small as possible, The challenge is to prevent lightning strikes to the ground.

[0010]

According to the present invention, this problem is solved by a wind power generator including a wind power generator having a plurality of blades rotated by wind power, and a wind turbine tower mounting the power generator. In the above, it is achieved by attaching to the wind turbine tower a metal member at a ground potential for discharging the charged electric charge of the tip portion of the blade at a position separated from the tip of the blade.

That is, according to the present invention, a metal member for discharging is attached to the wind turbine tower itself, and the metal member is positioned in the vicinity of the tip of the blade which is largely rotating, so that the blade is positioned in the vicinity of the metal member. Each time it passes through, electric discharge to the ground via the metal member is performed.

Since the number of blades in most cases is three, there are three discharge opportunities for the entire blade per revolution of the wind turbine. However, if the insulation resistance between the blades is large, one revolution per wind turbine occurs for each blade. It is possible to discharge once. The wind turbine rotates at a rate of about once every 2.5 to 3 seconds, but this discharge interval is sufficient to achieve the object of the present invention.

As is well known, the direction of the wind turbine in the wind turbine generator is not limited to one direction, and therefore the metal member must be able to secure the position near the tip of the blade even if the direction of the wind turbine changes. For this purpose, it is possible to move the metal member in conjunction with the direction of the wind turbine,
In consideration of the ease of installation and maintenance, the tip of the blade of the wind turbine can be surely placed in any wind direction by arranging a plurality of metal members around the wind turbine tower or by fixedly disposing a ring-shaped or annular metal member. It is preferable to be able to face the metal member.

Thus, the invention according to claim 2 is characterized in that the metal member is an arcuate or annular metal linear member located below the lowermost end position of the blade.

Further, the invention according to claim 3 is characterized in that the metal member is one or more upward metal needle-like members located below the lowermost end position of the blade.

In carrying out the present invention, it is necessary to design the width, depth or shape of the metal member in consideration of the fact that the blade often bends toward the generator side by wind force, and the wind direction. It is necessary to pay attention to the fact that the metal members are arranged so as to be concentrated in the main direction of the wind at a point where is concentrated within a specific range.

[0017]

1 shows an embodiment of the present invention, in which a gearbox 4 and an upper control panel are mounted on a bed frame 2 provided at the top of a wind turbine tower 1 made of steel or concrete. 5, a nacelle 3 for accommodating the generator 6 and the like is placed, and a blade 8 which is normally composed of three blades is coupled to a rotary shaft of the speed increaser 4. A nacelle upper lightning rod 7 is erected on the upper portion of the nacelle 3 and plays a role of guiding a lightning current to the ground through a grounding conductor 10 together with a lightning conductor 9 provided in the blade. Reference numeral 11 is a lightning conductor connecting terminal for connecting the ground conductor 10 to a reliable grounding body such as a steel tower foundation. Reference numeral 12 denotes a ground control panel, which controls the control of electric equipment together with the upper control panel 5.

Although these are also provided in the conventional equipment, according to the present invention, the support member 1 is provided at a position slightly lower than the lowermost position of the blade of the wind turbine tower 1.
The metal member 13 supported by 4 is disposed so as to face the tip of the blade.

In the embodiment shown in FIGS. 2 and 3, the metal member 13 is a ring-shaped member 131, 1 having a sharp tip.
32,133. Although the blade 8 of the wind turbine is at the position A at no wind or slight breeze position, when it receives a head wind, it bends inward and warps as shown in FIG. B. Therefore, in this embodiment, when the blade 8 is at the position A, metal is used. The member 133 is
When the blade 8 is at the position B, the metal member 1
31 and metal member 132 for average wind speeds
Are opposed to the tip of the blade 8. The number of rings of the ring-shaped metal member can be arbitrarily selected.

When installed in an area where the head wind does not fluctuate significantly, the metal member 13 should be a single ring as shown in FIGS. 4 and 5 so that it faces the blade between the positions A and B. May be.

The metal member does not necessarily have to be ring-shaped, and may be a needle-shaped member that is planted on the circumference at appropriate intervals.

When the direction of the wind with respect to the wind turbine is constant throughout the year or when the wind turbine is installed in an area limited to a certain range, the metal member may be arranged only on the windward side.

If the complexity is acceptable, the metal member is a needle-like member implanted on the ring-shaped support, and the ring-shaped support is rotated according to the rotation of the nacelle or the direction of the wind. Thus, the needle-shaped metal member may constantly face the tip of the blade.

If the wind turbine tower itself is a steel frame tower and the ground resistance of the foundation is sufficiently low, use the steel frame of the tower directly as a conductor without using a ground conductor or the like. You can also

[0025]

As described above, according to the present invention, only by attaching the grounded metal member to the wind turbine tower itself,
Since the electric field at the tip of the blade can be relaxed, it can be easily applied to existing wind power generation equipment and can be installed in offshore equipment at a low cost.

Also, if it is of a few hundred KW class, it is not as big as a windmill tower, but the nacelle is placed on a slightly thick metal pole, and a metal member is attached to the pole via an appropriate mounting tool. A good effect can be expected if the blades are arranged circumferentially and face the blade.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the present invention.

FIG. 2 is a partially enlarged view of the embodiment of the present invention.

FIG. 3 is a plan view of a metal member according to an embodiment of the present invention.

FIG. 4 is a partially enlarged view of another embodiment of the present invention.

FIG. 5 is a plan view of a metal member according to another embodiment of the present invention.

FIG. 6 is a side view of a conventional example.

[Explanation of symbols] 1 windmill tower 2 bed frame 3 nacelle 8 blades 13 Metal members 14 Support members

Claims (3)

[Claims] 1. A wind power generator comprising a wind power generator equipped with a plurality of blades that are rotated by wind power, and a wind turbine tower equipped with the power generator, wherein the tip of the blade is separated from the tip of the blade. A lightning arrester for a wind turbine generator, wherein a grounded metal member for discharging a charged electric charge of a part is attached to a wind turbine tower. 2. The lightning protection device for a wind turbine generator according to claim 1, wherein the metal member is an arcuate or annular metal linear member located below the lowermost end position of the blade. 3. The lightning arrester for a wind turbine generator according to claim 1, wherein the metal member is one or more upward-facing metal needle-shaped members located below the lowermost position of the blade.