Lightning-suppressed wind power generation equipment

Abstract

The aim is to easily apply existing lightning suppression devices to wind turbines. [Solution] The present invention, which solves the above problems, is a lightning-suppression type wind power generation facility X comprising: an erected support column 11; a generator 12 provided on the upper part of the support column 11 via the support column 11; a hub H provided on a drive shaft 13 that rotates the generator 12; a plurality of blades B provided radially on the hub H with the drive shaft 13 as the center; a charged body E provided at the tip of these blades B; and a capacitor provided in the internal space of the hub H, wherein the capacitor has a first electrode body 42 grounded via a grounding wire L, and a second electrode body 43 that surrounds the first electrode body 42 substantially over its entirety via an electrical insulating layer 44 or an electrical insulator 45 and is connected to the charged body E.

Description

Technical Field

[0001] The present invention relates to a lightning strike suppression type wind power generation facility having a function of suppressing lightning strikes on wind power generation facilities and protecting the wind power generation facilities from lightning damage.

Background Art

[0002] A lightning strike is a discharge phenomenon that occurs in the atmosphere. Lightning discharges include intra-cloud discharges, inter-cloud discharges, cloud-to-ground discharges, etc. The cloud-to-ground discharge (hereinafter, lightning strike) causes significant damage in lightning discharges. A lightning strike (ground discharge) usually occurs under a cumulonimbus cloud (a cloud commonly called a thundercloud). When the charge amount in the cloud increases and a strong electric field is formed that exceeds the dielectric breakdown of the air between the cloud and the ground, a lightning strike occurs. Here, the mechanism of a lightning strike will be described in more detail below.

[0003] Positive and negative charges are generated and accumulated in the cloud. This is increased by the interaction between the updraft and particles (hail, ice crystals, water droplets, etc.) passing through various temperature zones in the atmosphere. That is, first, the moist air near the ground surface is transported into the sky by the updraft. As the temperature of the atmosphere decreases with altitude, the water vapor eventually reaches a saturated state. Then, at the boundary of -10 degrees, hail becomes negatively charged and ice crystals become positively charged. The light ice crystals are carried upward by the updraft, and the heavy hail is located downward, so that positive and negative charges are distributed in the cloud. On the other hand, on the ground surface, opposite-polarity charges (positive charges) corresponding to the charges at the cloud base gather due to the electrostatic induction effect. As they accumulate, the voltage between the cloud and the ground increases. Eventually, the insulation by the atmosphere is broken and they are electrically connected, resulting in a discharge between the ground surface and the cloud.

[0004] In addition, a lightning strike does not occur unless the electric field near the ground surface becomes about 100 to 150 times larger than the clear-day electric field (about +100 to 200 volts per meter). In the case of winter lightning, it can be even one order of magnitude larger, and the electric field near the ground surface can become more than 1000 times larger than the clear-day electric field. When a strong electric field forms near the Earth's surface, all objects protruding from the ground begin to release positive and negative ions, known as "corona discharge," towards the opposite-sign thundercloud base in the upper atmosphere. This is the phenomenon known as "pre-emptive discharge," which occurs just before a lightning strike.

[0005] In response to such lightning strikes, conventional lightning protection concepts assumed that lightning strikes could not be prevented, and therefore, the majority of methods involved using a pointed lightning rod (Franklin rod) to receive the lightning and channel it to the ground. In other words, conventional lightning rods worked by amplifying the aforementioned welcoming discharge phenomenon, thereby "actively" attracting lightning to the lightning rod itself.

[0006] In response to this, the present inventors proposed a lightning suppression device as shown in Patent Document 1 or Patent Document 2 in order to protect the protected object by suppressing the occurrence of lightning strikes as much as possible.

[0007] This lightning suppression device has an external electrode body and an internal electrode body (or an upper electrode body and a lower electrode body) arranged with an electrical insulator in between, and is configured with only the internal electrode body (lower electrode body) grounded.

[0008] For example, when a thundercloud with negative charges distributed at its base approaches, the opposite charge (positive charge) is distributed on the surface of the earth, and the internal electrode body (lower electrode body) that is grounded also becomes positively charged. Because the external electrode (upper electrode) is positioned around (above) the internal electrode (lower electrode) with an insulator containing an air layer in between, these external and internal electrodes (upper and lower electrodes) function as a capacitor with the internal electrode (lower electrode) grounded.

[0009] This suppresses the flow of charge that generates the incoming discharge from the surface of the earth to the surface of the external electrode body (upper electrode body) until the capacitor discharge breakdown occurs, thereby suppressing the incoming discharge that causes lightning strikes. As a result, lightning strikes can now be suppressed within the protected area centered around the lightning suppression device. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Patent No. 6128539 [Patent Document 2] Patent No. 5839331 [Patent Document 3] Japanese Patent Publication No. 2024-038953 [Overview of the project] [Problems that the invention aims to solve]

[0011] Incidentally, in recent years, wind power generation facilities have been attracting attention as a renewable energy source for power generation.

[0012] This wind power generation facility consists of a generator, enclosed by a nacelle, mounted on top of a support structure, with multiple blades attached to the generator to drive its rotation. Furthermore, some of the larger blades mentioned above can exceed 100 meters in length.

[0013] Thus, the upper part of the wind power generation equipment is positioned close to the thundercloud, and the tip of the blade, in particular, moves closer to the thundercloud as it rotates, making it more susceptible to lightning strikes.

[0014] Therefore, the inventors concluded that it would be effective to provide the aforementioned lightning suppression function to the tip of the blade in order to suppress lightning strikes on wind power generation equipment. On the other hand, even if the aforementioned lightning suppression function is added to the tip of the blade, the effect obtained is merely "suppression" of lightning strikes, and lightning strikes may still occur. In this case, transient lightning surges could damage the blades or the wind turbine equipment itself.

[0015] Therefore, the present inventors have proposed a lightning-suppression type wind power generation equipment and a wind turbine for wind power generation shown in Patent Document 3, with the aim of providing a lightning-suppression effect to the blades and suppressing damage to the blades, etc., even in the event of a lightning strike.

[0016] This lightning-suppression wind power generation equipment and wind turbine are described in two ways: firstly, a configuration in which cylindrical capacitors are arranged in a ring shape inside the hub of the wind turbine, and the negative charge of the capacitors is guided from the hub to the tip of the blades, thereby providing a lightning suppression effect to the blades; and secondly, a configuration in which a spherical lightning suppression device is provided as a capacitor at the tip of the blades. Of the above configurations, the configuration with the capacitor inside the hub is more practical in terms of the difficulty of actual application to wind turbines, and can be added not only to newly constructed wind turbines but also to existing wind turbines used for wind power generation.

[0017] However, the above invention had a problem in that the cylindrical capacitor occupied most of the space in the hub, and the configuration of the capacitor was specific to the wind turbine hub, making it incompatible with lightning suppression devices that can be installed on other buildings, etc. Furthermore, although this invention can suppress lightning strikes on the blades, it does not have a lightning suppression effect on the nacelle, and a separate lightning suppression device needs to be installed on the top of the nacelle, so it would be preferable if the configuration of this device and the aforementioned capacitor could be made common.

[0018] In view of the above problems, the present invention aims to provide a lightning-suppression type wind power generation system to which existing lightning suppression devices can be easily applied. [Means for solving the problem]

[0019] The invention of the present application for solving the above problems includes a standing column, a generator provided at the upper part of the column via the column, a hub provided on a drive shaft for rotationally driving the generator, a plurality of blades radially provided on the hub around the drive shaft, a charged body provided at the tip of these blades, and a capacitor provided in the internal space of the hub. The capacitor has a first electrode body grounded via a ground wire, and a second electrode body that surrounds the first electrode body substantially entirely via an electrical insulation layer or an electrical insulator and is connected to the charged body. It is a lightning strike suppression type wind power generation facility. With such a configuration, an existing lightning strike suppression device can be easily applied to a windmill.

[0020] Another aspect of the invention of the present application for solving the above problems includes a standing column, a generator provided at the upper part of the column via the column, a hub provided on a drive shaft for rotationally driving the generator, a plurality of blades radially provided on the hub around the drive shaft, a charged body provided at the tip of these blades, and a capacitor provided in the internal space of the hub. The capacitor has a first electrode body grounded via a ground wire, and a second electrode body that faces the first electrode body via an electrical insulator and is connected to the charged body. It is a lightning strike suppression type wind power generation facility. With such a configuration, an existing lightning strike suppression device can be easily applied to a windmill.

[0021] In a preferred form of the present invention, the capacitors are provided one by one for each of the blades. With such a configuration, symmetry is provided to the mechanism from the hub to the blade tip, facilitating the construction and maintenance of the power generation facility.

[0022] In a preferred form of the present invention, it further includes a switching unit capable of switching between an operating state in which the charged body is electrically connected to the second electrode body and a resting state in which the charged body is grounded. With such a configuration, safety during maintenance work can be ensured.

Effects of the Invention

[0023] The present invention, which solves the above problems, provides a lightning-suppression type wind power generation system to which existing lightning suppression devices can be easily applied. [Brief explanation of the drawing]

[0024] [Figure 1] This is a schematic diagram showing a lightning-suppression type wind power generation facility according to an embodiment of the present invention. [Figure 2] This is a perspective view showing the upper part of a wind turbine according to an embodiment of the present invention. [Figure 3] This is an enlarged longitudinal cross-sectional view showing a blade according to an embodiment of the present invention. [Figure 4] This is an enlarged longitudinal cross-sectional view showing an electrical resistor according to an embodiment of the present invention. [Figure 5] This is a cross-sectional view showing a nacelle and a hub according to an embodiment of the present invention. [Figure 6] This is a cross-sectional view showing the configuration of a lightning suppression device as a capacitor according to an embodiment of the present invention. [Figure 7] This is an explanatory diagram showing examples of modifications to the nacelle and hub, and the configuration of a lightning suppression device according to an embodiment of the present invention. [Modes for carrying out the invention]

[0025] The following describes the lightning-suppression type wind power generation equipment X according to each embodiment of the present invention with reference to the drawings. The description will detail the configuration of the embodiment, the method of implementation, and other embodiments in that order. The embodiments described below are merely examples of the present invention, and the present invention is not limited to these embodiments.

[0026] ≪First Embodiment≫ As shown in Figure 1, the lightning-suppression type wind power generation facility X comprises a wind turbine 1 that generates electricity and a power transmission facility 3 that transmits the electricity generated by the wind turbine 1 via a power transmission line 2.

[0027] As shown in Figures 1 to 3, the wind turbine 1 for wind power generation includes a support column 11 erected on the ground G, a generator 12 provided on the upper part of the support column 11, a hub H provided on a drive shaft 13 that rotates the generator 12, a plurality of blades B provided radially on the hub H with the drive shaft 13 as the center, a charged body E provided at the tip of the blades B, a lightning suppression device 4 (described later) provided in the internal space of the hub H as a capacitor that supplies charge to the charged body E, and an electrical resistor R that converts a portion of the discharge energy of a lightning strike into thermal energy, with the blades B acting as receptors.

[0028] With the above configuration, the wind turbine 1 converts wind energy into rotational motion using multiple blades B, and generates electricity by driving the generator 12 with this rotational motion.

[0029] The support column 11 has a grounding wire L inside, which is a conductive member capable of electrically connecting from inside the nacelle N to the ground G. This guides the electric charge that occurs when the ground G becomes charged to the ground side of the lightning suppression device 4.

[0030] In addition, the wind turbine 1 for wind power generation has a transmission 14 and a rotating electrical contact 15. The transmission 14 and the generator 12 are housed in the nacelle N together with a portion of the drive shaft 13. The rotating electrical contact 15 is interposed between the nacelle N and the hub H and is electrically connected to the ground wire L. Furthermore, the configuration of the nacelle N (generator 12, drive shaft 13, transmission 14), hub H, and rotating electrical contact 15 described above is the same as that of known wind turbines for wind power generation.

[0031] As shown in Figure 3, the blade B has a hollow section k formed along almost its entire length. Furthermore, the blade B is provided with a flange f1 at its base, and the flange f1 is fastened to a flange f2 provided on the hub H by numerous fastening members t (bolts and nuts), thereby fixing the blade B to the hub H. Blade B, like other known wind turbines, is made of fiber-reinforced plastic such as fiberglass.

[0032] The charged body E is electrically connected to one of the electrodes of the lightning suppression device 4 (described later) via an electrical resistor R located inside the blade B. Furthermore, the charged element E is provided at the tip of the blade B via the blade-side insulator I.

[0033] As shown in Figure 4, the electrical resistor R has an elongated, roughly cylindrical shape that extends over almost the entire length of the blade B, and in this embodiment, it includes a support cylinder R1 and a nonmetallic heating element R2 sealed inside the support cylinder R1.

[0034] The support cylinder R1 is composed of a support cylinder body R11 with openings at both ends, and a lid portion R12 that closes each opening of the support cylinder body R11. In this case, the support cylinder body R11 can be formed from an insulator, and the lid R12 can be formed from a conductor.

[0035] The nonmetallic heating element R2 is filled into the support cylinder R1 and can be formed from a ceramic mainly composed of a material selected from the group including SiC, MoSiO2, and ZrO2.

[0036] Furthermore, the form of the non-metallic heating element R2 may be powder, sintered body, or porous body, and there are no restrictions on its material or ratio. In addition, the material for the non-metallic heating element R2 may be a graphite electrode made of a ceramic mainly composed of graphite, or a flexible conductive structure such as a conductive gel, conductive rubber, or conductive elastomer.

[0037] Here, the electrical resistor R has male threaded portions m formed at both ends, and the electrical resistor R is fixedly supported in the hollow portion k by these male threaded portions m and the fixing means T.

[0038] More specifically, the fixing means T is formed by a first plate T1 provided in the hollow portion k and in contact with the base end of the charged body E, a second plate T2 hooked onto the base end of the blade B, and a plurality of nuts T3 that are screwed onto each male screw portion m, as shown in Figure 3. Furthermore, the first plate T1 and the second plate T2 can be constructed as insulators, and an electrical resistor R passes through each of them.

[0039] The male screw portion m on the charged body E side is screwed into a screw hole h formed in the charged body E and communicating with the hollow portion k. Furthermore, the nut T3 on the charged body E side is screwed into the male threaded portion m in such a manner that it sandwiches the first plate T1 between the charged body E and the electrical resistor R, thereby connecting the charged body E and the electrical resistor R. Furthermore, the nut T3 on the hub H side clamps and fixes the metal plate j, through which the electrical resistor R passes, between itself and the second plate T2, and the electric wire W is attached to the metal plate j.

[0040] As shown in Figure 5(a), a mounting shaft A is provided inside the hub H, extending from the base of the drive shaft 13 or the rotating electrical contact 15. Furthermore, as shown in Figure 5(b), multiple lightning suppression devices 4 are provided radially from the mounting shaft A in the same direction as the blades B. In this case, it is preferable that one lightning suppression device 4 is provided for each blade B, in line with the direction in which the blades B are provided. With this configuration, the space occupied inside the hub H can be minimized, and since the configuration from the blades B to the hub H is rotationally symmetrical, the installation and removal of the lightning suppression devices 4, as well as maintenance work on the entire inside of the hub H, can be made more efficient.

[0041] Mounting shaft A is a conductive shaft member that electrically connects the ground side of the lightning suppression device 4 to the rotating electrical contact 15, and is supported by shaft support D inside the hub H.

[0042] The shaft support D preferably consists of a support portion D1 that extends inward from the outer wall of the hub H and supports the mounting shaft A, and an insulating portion D2 that holds the mounting shaft A while insulating it. With this configuration, the electrical connection path from the mounting shaft A to the ground wire L is limited to a path via the rotating electrical contact 15, thereby limiting the charged area and maintaining safety within the hub.

[0043] Figure 6 shows the configuration of the lightning suppression device 4 and the mounting shaft A. The lightning suppression device 4 has a connecting column 41 fixed in a direction intersecting the mounting shaft A and electrically connected, a first electrode body 42 provided at the tip of the connecting column 41, and a second electrode body 43 that surrounds the first electrode body 42 over substantially its entirety via an electrical insulating layer 44 and / or an electrical insulator 45. The lightning suppression device 4 also has an insulating covering portion 46 that covers the space between the second electrode body 43 and the mounting shaft A, and around the connection portion between the connecting column 41 and the mounting shaft A.

[0044] With this configuration, the first electrode body 42 is electrically connected to the ground G, and under lightning strike conditions, a positive charge is induced from the ground G through the grounding wire L, rotating electrical contact 15, mounting shaft A, and connecting pole 41, as described above. In contrast, the second electrode body 43 becomes negatively charged.

[0045] The second electrode body 43 is electrically connected to the charged body E via the electric wire W. When the second electrode body 43 becomes negatively charged, a negative charge is induced in the charged body E, forming a capacitor via the lightning suppression device 4 from the blade B to the inside of the hub H, thereby exhibiting a lightning suppression effect.

[0046] In this embodiment, as shown in Figure 6, a configuration in which a switch S is provided between the second electrode body 43 and the charged body E is preferred. The switch S is a switching unit that can switch the electrical connection path to either of two directions. The base side of the switch S is connected to the blade-side wire W1 that connects to the charged body E, and the branch side of the switch S is connected to the electrode-side wire W2 that connects to the second electrode body 43 and the ground-side wire W3 that connects to the mounting shaft A (or any member electrically connected to the ground wire L).

[0047] Switching the switch S allows for switching between two states: one in which the blade-side wire W1 and the electrode-side wire W2 are connected, and another in which the blade-side wire W1 and the ground-side wire W3 are connected. The former is the operating state in which the second electrode body 43 and the charged body E are electrically connected, and the latter is the dormant state in which the charged body E is grounded (electrically connected to the ground G via the mounting shaft A or grounding wire L, etc.). This reduces the number of charged components when workers enter the wind turbine 1 (especially the inside of the hub H) to perform maintenance work, making it easier to ensure the safety of the workers.

[0048] The present invention may have the following configurations. However, the following configurations are merely examples, and their presence or absence can be arbitrarily determined unless otherwise specified.

[0049] ≪Example of changes≫ As shown in Figures 7(a) and 7(b), the lightning suppression device 4 installed inside the hub H may have a configuration that includes a first electrode body 42 grounded via the same configuration as the grounding wire L including the connecting pole 41 described above, and a second electrode body 43 facing the first electrode body 42 via an electrical insulator 45 and connected to the charged body E via an electric wire W.

[0050] In the above modified example, the first electrode body 42 and the second electrode body 43 are either bowl-shaped, hemispherical, or flattened hemispherical, and face each other, sandwiching the electrical insulator 45 between their open annular edges. The electrical insulator 45 is cylindrical or annular (cylindrical). With this configuration, the structure is simpler compared to the aforementioned spherical lightning suppression device 4, and the lightning suppression device 4 can be easily installed inside the hub H with fewer parts.

[0051] The configurations shown above, including the modified examples, are merely illustrative and can be modified in various ways based on design requirements. [Explanation of symbols]

[0052] X Lightning-suppressed wind power generation equipment 1. Wind turbine for wind power generation 2 Power transmission lines 3. Power transmission equipment 4. Lightning suppression device 41 Connecting Pillars 42 First electrode body 43 Second electrode body 44 Electrical insulation layer 45 Electrical insulators 46 Covering part A Mounting shaft B Blade D axis support D1 Support part D2 Insulation E charged body F flange G ground H Hub I. Blade-side insulator L Ground wire N Nacelle R is an electrical resistor. R1 support tube R2 Nonmetallic heating element S Switch W electric wire W1 Blade-side wire W2 Electrode-side wire W3 Ground side wire

Claims

1. The device comprises an upright support column, a generator mounted on the upper part of the support column via the support column, a hub mounted on a drive shaft that rotates the generator, a plurality of blades arranged radially on the hub with respect to the drive shaft, charged bodies provided at the tips of these blades, and a capacitor provided in the internal space of the hub. The capacitor comprises a first electrode body grounded via a grounding wire, and a second electrode body that substantially surrounds the first electrode body via an electrical insulating layer or electrical insulator and is connected to the charged body, wherein the capacitor is a lightning-suppression type wind power generation facility.

2. The device comprises an upright support column, a generator mounted on the upper part of the support column via the support column, a hub mounted on a drive shaft that rotates the generator, a plurality of blades arranged radially on the hub with respect to the drive shaft, charged bodies provided at the tips of these blades, and a capacitor provided in the internal space of the hub. The capacitor is a lightning-suppression type wind power generation facility having a first electrode body grounded via a grounding wire and a second electrode body facing the first electrode body via an electrical insulator and connected to the charged body.

3. The capacitors are provided one for each of the blades. A lightning-suppression type wind power generation facility according to either claim 1 or 2.

4. The system further includes a switching unit capable of switching between an operating state in which the charged body is electrically connected to the second electrode body and a resting state in which the charged body is grounded. A lightning-suppression type wind power generation facility according to either claim 1 or 2.

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