Lightning strike suppression type lightning protection device

Abstract

Provided is a lightning strike suppression type lightning protection device that is excellent in the isotropy of lightning protection performance and can be easily installed. Provided is a lightning strike suppression type lightning protection device in which the withstand voltage insulation can be easily adjusted. 【Solution means】A lightning protection device 1 which is a lightning strike suppression type lightning protection device includes an internal electrode 2 grounded, and an external electrode that is electrically insulated from the internal electrode 2 and includes an internal IS that houses the internal electrode 2, the external electrode 3. The internal electrode 2 has an annular shape surrounding a central axis AX extending in the vertical direction, and the external electrode 3 has an annular shape surrounding the central axis AX. The external electrode 3 includes an inner diameter side portion 31 facing the outer peripheral surface 21 on the inner diameter side of the internal electrode 2, and an outer diameter side portion 31 facing the outer peripheral surface 22 on the outer diameter side of the internal electrode 2.

Description

Technical Field

[0001] The present invention relates to a lightning strike suppression type lightning protection device. More specifically, the present invention relates to a lightning strike suppression type lightning protection device having excellent isotropy of lightning protection performance and capable of suppressing a decrease in lightning protection performance.

Background Art

[0002] When clouds are generated, dust and ice particles in the clouds collide with each other, small particles are charged with positive charges, large particles are charged with negative charges, positive charges gather above the clouds, and negative charges gather below the clouds. When negative charges gather below the clouds, positive charges are induced on the ground surface, and the negative charges gathered below the clouds are attracted to the positive charges on the ground surface, resulting in a lightning strike. A general lightning rod includes a grounded pointed tip, and positive charges are concentrated at this tip. Thereby, the negative charges gathered below the clouds are safely conducted to the ground surface through the lightning rod, ensuring the safety around the lightning rod (in the case of winter lightning, since the updraft is not as strong as in summer, the lower particles (heavy graupel, etc.) carrying negative charges fall in a short time, and only the upper positive-charged particles remain. Therefore, positive charges gather below the clouds and the polarities of the cloud base and the ground surface are reversed. Thus, the polarities in the corresponding description of this case should be readjusted).

[0003] In recent years, a lightning strike suppression type lightning protection device called PDCE has been proposed. The lightning strike suppression type lightning protection device includes a first electrode and a second electrode arranged with an insulator therebetween. Only the first electrode is grounded, and the second electrode is arranged at a position more likely to be struck by lightning than the first electrode. When a cloud with negative charges gathering below approaches, positive charges opposite thereto are induced on the ground surface, attracted to the positive charges on the ground surface, and positive charges also gather on the first electrode. Then, due to the action of a capacitor, the second electrode is charged negatively. By this action, it becomes difficult for lightning to strike the second electrode, and the occurrence of lightning strikes on the lightning strike suppression type lightning protection device itself and its surroundings is suppressed.

[0004] Conventional lightning strike suppression lightning arresters are disclosed, for example, in Patent Documents 1 and 2 below. Patent Document 1 below discloses a lightning strike suppression lightning arrester including a grounded inner electrode body, an outer electrode body provided so as to surround the inner electrode body with a predetermined gap, an electrical insulation layer provided in the gap to keep the inner electrode body and the outer electrode body in an electrically insulated state, and a support body that supports at least one of the inner electrode body and the outer electrode body. The inner electrode body is formed in a rod shape, and the outer electrode body is formed in a cylindrical shape. This lightning strike suppression lightning arrester is provided over the entire circumference so as to surround the peripheral portion of the rooftop of a building in a long state.

[0005] Patent Document 2 below discloses a lightning strike suppression lightning arrester including a grounded second electrode body, a first electrode body provided so as to surround the second electrode body with a predetermined gap, and an electrical insulation layer provided in the gap to keep the second electrode body and the first electrode body in an electrically insulated state. The second electrode body has a substantially spherical shape, the first electrode body has a spherical shell shape similar to the outer surface shape of the second electrode body, and the second electrode body is almost entirely covered by the first electrode body.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the lightning strike suppression type lightning arrester of Patent Document 1, since the outer electrode body extends linearly when viewed from above, the lightning protection performance in the direction orthogonal to the extending direction is lower than the lightning protection performance in the extending direction of the outer electrode body. For this reason, the technique of Patent Document 1 has a problem of poor isotropy of lightning protection performance. In addition, since the falling body suppression type lightning arrester of Patent Document 1 needs to be installed over the entire circumference so as to surround the peripheral portion of the rooftop of the building in a long state, problems occur in terms of weight, size, and cost, and it was not easy to install.

[0008] In the lightning strike suppression type lightning protection device of Patent Document 2, both the first and second electrode bodies are formed of spherical surfaces, and the distance between the first electrode body and the second electrode body is uniform throughout. For this reason, when trying to increase the withstand voltage of the lightning strike suppression type lightning protection device of Patent Document 2, in order to uniformly move the first electrode body away from the second electrode body throughout, it is necessary to increase the diameter of the first electrode body and enlarge the entire first electrode body. For this reason, the lightning strike suppression type lightning protection device of Patent Document 2 has a problem that it is not easy to adjust the withstand voltage.

[0009] The present invention is for solving the above problems, and one of its objects is to provide a lightning strike suppression type lightning protection device having excellent isotropy of lightning protection performance and being easily installable.

[0010] Another object of the present invention is to provide a lightning strike suppression type lightning protection device in which the adjustment of the withstand voltage is easy.

Means for Solving the Problems

[0011] A lightning strike suppression type lightning protection device according to one aspect of the present invention includes a grounded internal electrode and an external electrode electrically insulated from the internal electrode, the external electrode including an interior that houses the internal electrode. The internal electrode has an annular shape surrounding a central axis extending in the vertical direction, the external electrode has an annular shape surrounding the central axis, and the external electrode includes an inner diameter side portion facing the outer peripheral surface on the inner diameter side of the internal electrode and an outer diameter side portion facing the outer peripheral surface on the outer diameter side of the internal electrode.

[0012] In the above lightning strike suppression type lightning arrester, preferably, when viewed in a cross section including the central axis, the external electrode includes a first external electrode portion that exists on one side of the central axis and has an elliptical outer shape with a major axis in the vertical direction, and a second external electrode portion that exists on the other side of the central axis and has an elliptical outer shape with a major axis in the vertical direction.

[0013] In the above lightning strike suppression type lightning arrester, preferably, the external electrode further includes a connection hole that connects the inside and the outside of the external electrode, and further includes a grounding conductor that is a grounded conductor and a connection conductor that penetrates the connection hole and electrically connects the grounding conductor and the internal electrode.

[0014] In the above lightning strike suppression type lightning arrester, preferably, the grounding conductor includes a columnar portion extending along the central axis, each of the internal electrode and the external electrode surrounds the columnar portion, the connection hole is provided in the inner diameter side portion, and the connection conductor extends from the columnar portion and reaches the outer peripheral surface on the inner diameter side of the internal electrode.

[0015] In the above lightning strike suppression type lightning arrester, preferably, the external electrode further includes a central hole surrounded by the inner diameter side portion, a columnar portion insulating portion that covers at least a part of the outer peripheral surface of the columnar portion, and an upper insulating portion provided on the columnar portion insulating portion and covering the central hole and the upper end portion of the external electrode. When viewed in a cross section including the central axis, the horizontal width of the upper insulating portion increases downward from the upper end portion of the upper insulating portion.

[0016] In the above lightning strike suppression type lightning arrester, preferably, the grounding conductor includes a columnar portion extending along the central axis and a protruding portion protruding in the outer diameter direction from the columnar portion, and the connection conductor extends upward from the protruding portion and reaches the internal electrode.

[0017] In the above lightning strike suppression type lightning arrester, preferably, the external electrode includes a central hole surrounded by the inner diameter side portion, a columnar portion insulating portion that covers at least a part of the outer peripheral surface of the columnar portion, and a lower insulating portion provided at the lower portion of the external electrode. The lower insulating portion protrudes in the outer diameter direction from the columnar portion insulating portion and includes a plurality of protruding portion insulating portions that cover the protruding portion, and is provided on the outer diameter side of the columnar portion insulating portion and has a plurality of protrusions PartIt includes an annular insulating part that connects each of the insulating parts, and a lower hole that is provided between each of the plurality of protruding insulating parts and connects to the central hole.

Advantages of the Invention

[0018] According to the present invention, it is possible to provide a lightning strike suppression type lightning protection device that has excellent isotropy in lightning protection performance and can be easily installed. Further, according to the present invention, it is possible to provide a lightning strike suppression type lightning protection device in which the adjustment of the insulation withstand voltage is easy.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Best Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0021] [First Embodiment]

[0022] FIG. 1 is a cross-sectional view showing the configuration of a lightning protection device 1 in the first embodiment of the present invention, which is a cross-sectional view when cut by a plane orthogonal to the central axis AX. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 1 corresponds to a cross-sectional view taken along line I-I in FIG. 2.

[0023] Referring to FIGS. 1 to 3, the lightning protection device 1 (an example of a lightning strike suppression type lightning protection device) in the present embodiment is a lightning strike suppression type lightning protection device that suppresses lightning strikes by an electrode charged negatively, and includes an internal electrode 2 (an example of an internal electrode), an external electrode 3 (an example of an external electrode), a ground conductor 4 (an example of a ground conductor), a connection conductor 5 (an example of a connection conductor), a columnar part insulating portion 61 (an example of a columnar part insulating portion), a coating insulating portion 62, an upper insulating portion 63 (an example of an upper insulating portion), a connection conductor insulating portion 64, and an electrode support portion 7 mainly. The lightning protection device 1 has a virtual central axis AX (an example of a central axis) extending in the vertical direction.

[0024] The internal electrode 2 is made of a conductor such as titanium and is grounded through the ground conductor 4, the connection conductor 5, etc. The internal electrode 2 has an annular shape surrounding the central axis AX. The internal electrode 2 preferably has an elliptical cross-sectional shape when viewed in a cross-section (the cross-sections of FIGS. 2 and 3) including the central axis AX, and more preferably has an elliptical cross-sectional shape having a major axis in the vertical direction. Thereby, the sharp portions in the internal electrode 2 are reduced, and the concentration of charges on the sharp portions can be suppressed. The outer peripheral surface 21 on the inner diameter side of the internal electrode 2 faces the side of the central axis AX, and the outer peripheral surface 22 on the outer diameter side of the internal electrode 2 faces the side opposite to the central axis AX.

[0025] Also, when viewed in a cross-section including the central axis AX, the internal electrode 2 includes an internal electrode portion 2a that exists on one side of the central axis AX (the left side in FIGS. 2 and 3) and has an elliptical shape with a major axis in the vertical direction, and an internal electrode portion 2b that exists on the other side of the central axis AX (the right side in FIGS. 2 and 3) and has an elliptical shape with a major axis in the vertical direction. Each of the internal electrode portions 2a and 2b includes an outer peripheral surface 21 on the inner diameter side and an outer peripheral surface 22 on the outer diameter side.

[0026] The external electrode 3 is made of a conductor such as titanium and is electrically insulated from the internal electrode 2. The external electrode 3 includes an internal IS (an example of the inside of the external electrode) that houses the internal electrode 2. The internal IS of the external electrode 3 is filled with air. The internal IS of the external electrode 3 may be filled with a solid insulator. The external electrode 3 has an annular shape surrounding the central axis AX, for example, a toroidal shape (a shape composed of a rotating surface obtained by rotating a circumference).

[0027] The external electrode 3 includes an inner diameter side portion 31 (an example of an inner diameter side portion), an outer diameter side portion 32 (an example of an outer diameter side portion), a central hole 33 (an example of a central hole of the external electrode), and a connection hole 34 (an example of a connection hole of the external electrode). The distance between the internal electrode 2 and the external electrode 3 continuously changes along the inner peripheral surface of the external electrode 3 shown in FIG. 3.

[0028] The inner diameter side portion 31 is a portion facing the outer peripheral surface 21 on the inner diameter side of the internal electrode 2.

[0029] The outer diameter side portion 32 is a portion facing the outer peripheral surface 22 on the outer diameter side of the internal electrode 2.

[0030] The central hole 33 is formed at a position including the central axis AX. The central hole 33 is defined by the inner diameter side portion 31 and surrounded by the inner diameter side portion 31. The central hole 33 is also surrounded by the outer peripheral surface 21 on the inner diameter side of the internal electrode 2.

[0031] The connection hole 34 connects the inside IS of the external electrode 3 and the outside of the external electrode 3. Here, the connection hole 34 is provided in the inner diameter side portion 31. The number of connection holes 34 is arbitrary, and here it is two. Each of the two connection holes 34 is provided at a position facing each other across the vicinity of the upper end of the columnar portion 41 in the inner diameter side portion 31.

[0032] The inside IS of the external electrode 3 and the outside of the external electrode 3 are partitioned by the inner diameter side portion 31 and the outer diameter side portion 32.

[0033] Also, when viewed in a cross-section including the central axis AX, the external electrode 3 includes an external electrode portion 3a (an example of a first external electrode portion) existing on one side of the central axis AX (the left side in FIGS. 2 and 3) and an external electrode portion 3b (an example of a second external electrode portion) existing on the other side of the central axis AX (the right side in FIGS. 2 and 3).

[0034] The external electrode portion 3a houses the internal electrode portion 2a in the inside IS. The inner diameter side portion 31 of the external electrode portion 3a faces the outer peripheral surface 21 on the inner diameter side of the internal electrode portion 2a. The outer diameter side portion 32 of the external electrode portion 3a faces the outer peripheral surface 22 on the outer diameter side of the internal electrode portion 2a.

[0035] The external electrode portion 3b houses the internal electrode portion 2b in the inside IS. The inner diameter side portion 31 of the external electrode portion 3b faces the outer peripheral surface 21 on the inner diameter side of the internal electrode portion 2b. The outer diameter side portion 32 of the external electrode portion 3b faces the outer peripheral surface 22 on the outer diameter side of the internal electrode portion 2b.

[0036] When viewed in a cross-section including the central axis AX, each of the external electrode portions 3a and 3b preferably has a shape in which the horizontal width of each of the external electrode portions 3a and 3b increases downward from the upper end portions 35 of each of the external electrode portions 3a and 3b. Thereby, when foreign matter such as bird droppings adheres to the external electrode 3, the foreign matter is likely to fall due to its own weight, and the adhesion of foreign matter to the external electrode 3 can be suppressed. Further, when viewed in a cross-section including the central axis AX, each of the external electrode portions 3a and 3b more preferably has an elliptical shape having a major axis in the vertical direction. Thereby, it is possible to avoid the occurrence of sharp portions in the external electrode 3, and it is possible to suppress the local concentration of negative charges on the external electrode 3.

[0037] The ground conductor 4 is a conductor to be grounded. The ground conductor 4 is made of, for example, stainless steel. The ground conductor 4 is electrically connected to the internal electrode 2 via the connection conductor 5. The ground conductor 4 includes a columnar portion 41 (an example of the columnar portion of the ground conductor).

[0038] The columnar portion 41 is, for example, cylindrical. The columnar portion 41 extends along the central axis AX and reaches inside the central hole 33 of the external electrode 3. The columnar portion 41 is surrounded by each of the internal electrode 2 and the external electrode 3. The lower portion of the columnar portion 41 is connected to the ground surface GR.

[0039] The connection conductor 5 is made of a conductor and electrically connects the ground conductor 4 and the internal electrode 2. The number of connection conductors 5 is arbitrary and is two here. Each of the two connection conductors 5 extends in the horizontal direction and penetrates each of the two connection holes 34. Each of the two connection conductors 5 extends from the outer peripheral surface of the columnar portion 41 and reaches the outer peripheral surface 21 on the inner diameter side of the internal electrode 2. Male threads or female threads are formed at both ends of the connection conductor 5. Female threads or male threads are formed on each of the outer peripheral surface of the columnar portion 41 and the outer peripheral surface 21 on the inner diameter side of the internal electrode 2. By fitting the male threads or female threads formed at both ends of the connection conductor 5 with the female threads or male threads formed on each of the outer peripheral surface of the columnar portion 41 and the outer peripheral surface 21 on the inner diameter side of the internal electrode 2, the connection conductor 5 is fixed to each of the columnar portion 41 and the internal electrode 2.

[0040] Each of the columnar portion insulating part 61, the covering insulating part 62, the upper insulating part 63, and the connection conductor insulating part 64 is made of an insulator, for example, a reinforced plastic such as GFRP (Glass Fiber Reinforced Plastic).

[0041] The columnar portion insulating part 61 is cylindrical and covers at least a part of the outer peripheral surface of the columnar portion 41. The columnar portion insulating part 61 penetrates the central hole 33.

[0042] The covering insulating part 62 covers a part of the outer peripheral surface of the columnar portion insulating part 61. The upper end portion of the covering insulating part 62 may extend in the outer diameter direction near the lower part of the external electrode 3. Male threads 621 are formed at the lower end portions of each of the columnar portion insulating parts 61 and 62. By fitting the male threads 621 formed at the lower end portions of each of the columnar portion insulating parts 61 and 62 with the female threads formed on the fixed object SP, the lightning protection device 1 is fixed to the fixed object SP. The covering insulating part 62 may be integrated with the columnar portion insulating part 61.

[0043] The upper insulating portion 63 is provided at the upper end portion of the columnar insulating portion 61. The upper insulating portion 63 covers the central hole 33 and the upper end portion 35 of the external electrode 3. When viewed in a cross-section including the central axis AX, the horizontal width of the upper insulating portion 63 increases downward from the upper end portion 631 of the upper insulating portion 63. The upper end portion 631 of the upper insulating portion 63 exists at a position overlapping the central axis AX and is preferably rounded.

[0044] The connection conductor insulating portion 64 is cylindrical. The number of the connection conductor insulating portions 64 is arbitrary, and here it is two. Each of the two connection conductor insulating portions 64 covers the outer peripheral surface of each of the two connection conductors 5 and extends in the horizontal direction. Each of the two connection conductor insulating portions 64 is provided between the outer peripheral surface of the columnar portion 41 and the outer peripheral surface 21 on the inner diameter side of the internal electrode 2. Each of the two connection conductor insulating portions 64 penetrates each of the two connection holes 34 and is in contact with the inner peripheral surface of each of the two connection holes 34.

[0045] The electrode support portion 7 is made of an insulator and fixes the internal electrode 2 to the inside IS of the external electrode 3 while insulating the internal electrode 2 from the external electrode 3. The shape of the electrode support portion 7 is arbitrary, but here it is four columns. Each of the four electrode support portions 7 is arranged at four positions equally spaced on a circumference centered on the central axis AX. Each of the four electrode support portions 7 extends upward from the inner peripheral surface of the lower end portion 36 of the external electrode 3. The electrode support portion 7 fixes the internal electrode 2 to the upper portion of the electrode support portion 7 by passing the internal electrode 2 through a hole provided in the upper portion of the electrode support portion 7. The method by which the electrode support portion 7 fixes the internal electrode 2 is arbitrary. For example, the electrode support portion 7 may fix the internal electrode 2 by sandwiching the outer peripheral surface 21 on the inner diameter side and the outer peripheral surface 22 on the outer diameter side of the internal electrode 2 with the U-shaped upper end portion.

[0046] FIG. 4 is a diagram for explaining the lightning strike suppression function by the lightning protection device 1 in the first embodiment of the present invention.

[0047] Referring to FIG. 4, when cloud CL occurs, positive charges gather above cloud CL and negative charges gather below cloud CL. When negative charges gather below cloud CL, positive charges opposite thereto are induced on the ground surface GR. Since the grounding conductor 4, the connection conductor 5, and the internal electrode 2 are grounded, positive charges also gather on the grounding conductor 4, the connection conductor 5, and the internal electrode 2. Since the external electrode 3 faces the internal electrode 2 with the insulating space IS in between, when the internal electrode 2 is charged with positive charges, it is charged with negative charges due to the action of the capacitor. Due to this action, it becomes difficult for lightning to strike the external electrode 3, and the occurrence of lightning strikes on the lightning protection device 1 itself and its surroundings is suppressed.

[0048] In the present embodiment, each of the internal electrode 2 and the external electrode 3 has an annular shape surrounding a central axis extending in the vertical direction. Thereby, an approximately equal amount of charge can be accumulated in any direction when viewed from the central axis AX with respect to the external electrode 3. As a result, a lightning strike suppression type lightning protection device with excellent isotropy of lightning protection performance is obtained. Further, the external electrode 3 includes an inner diameter side portion 31 facing the outer peripheral surface 21 on the inner diameter side of the annular internal electrode 2 and an outer diameter side portion 32 facing the outer peripheral surface 22 on the outer diameter side of the internal electrode 2. Thereby, the area of the portion of the external electrode 3 facing the internal electrode 2 is increased, and the area of the portion of the external electrode capable of accumulating negative charges can be increased. As a result, the lightning protection performance can be improved. Also, it is not necessary to install the lightning protection device over the entire circumference so as to surround the peripheral edge of the rooftop of the building in a long state, and the lightning protection device can be easily installed. Furthermore, since neither the internal electrode 2 nor the external electrode 3 is spherical, even when increasing the insulation withstand voltage of the lightning protection device, it is not necessary to uniformly separate the external electrode 3 from the internal electrode 2 over the entire body, and it is not necessary to increase the size of the entire external electrode 3. Therefore, adjustment of the insulation withstand voltage is easy.

[0049] In addition, since the external electrodes 3 include external electrode portions 3a and 3b having an elliptical outer shape with a major axis in the vertical direction when viewed in a cross section including the central axis, each of the external electrode portions 3a and 3b has a shape that bulges upward. As a result, foreign matter attached to each of the external electrode portions 3a and 3b is likely to fall due to gravity. In addition, since each of the external electrode portions 3a and 3b has an elliptical cross-sectional shape, sharp portions are less likely to occur in the external electrode 3 when viewed in a cross section including the central axis, and portions where electric charges concentrate locally in the external electrode 3 are less likely to occur. As a result, a decrease in lightning protection performance can be suppressed.

[0050] In addition, the external electrode 3 includes a connection hole 34, and the connection conductor 5 passes through the connection hole 34, facilitating electrical connection between the ground conductor 4 and the internal electrode 2.

[0051] In addition, by providing an upper insulating portion 63 that covers the central hole 33 and the upper end portion 35 of the external electrode 3, attachment of foreign matter to the upper portion of the external electrode 3 can be suppressed.

[0052] [Second Embodiment]

[0053] FIG. 5 is a cross-sectional view showing the configuration of the lightning protection device 1 according to the second embodiment of the present invention, and is a cross-sectional view when cut along a plane orthogonal to the central axis AX. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 5. FIG. 8 is a cross-sectional view showing the configuration near the lower insulating portion 65 of the lightning protection device 1 according to the second embodiment of the present invention, and is a cross-sectional view taken along line VIII-VIII in FIG. 6. FIG. 9 is an external view of the lightning protection device 1 when viewed from the horizontal direction in the second embodiment of the present invention. FIG. 10 is an external view of the lightning protection device 1 when viewed obliquely downward in the second embodiment of the present invention. FIG. 5 corresponds to a cross-sectional view taken along line V-V in FIG. 6.

[0054] Referring to FIGS. 5 to 10, in the lightning protection device 1 of the present embodiment, the connection holes 34 of the external electrode 3 are provided near the lower end portion 36 of the external electrode 3. The connection holes 34 connect the inside IS of the external electrode 3 and the outside of the external electrode 3. The number of the connection holes 34 is arbitrary, and here it is four. Each of the four connection holes 34 is provided at equal intervals along the annular lower end portion 36.

[0055] The ground conductor 4 includes a columnar portion 41 and a protruding portion 42 (an example of the protruding portion of the ground conductor). Each of the columnar portion 41 and the protruding portion 42 is, for example, columnar. The columnar portion 41 extends along the central axis AX below the external electrode 3 and does not reach the central hole 33 of the external electrode 3. The lower portion of the columnar portion 41 is grounded to the ground surface GR.

[0056] The protruding portion 42 protrudes in the outer diameter direction from the columnar portion 41. The number of the protruding portions 42 is arbitrary, and here it is four. Each of the four protruding portions 42 is provided at equal intervals along the outer periphery of the columnar portion 41 and extends to near the lower end portion 36 of the external electrode 3.

[0057] The connection conductor 5 is made of a conductor and electrically connects the ground conductor 4 and the internal electrode 2. The number of the connection conductors 5 is arbitrary, and here it is four. Each of the four connection conductors 5 extends in the vertical direction and penetrates each of the four connection holes 34. Each of the four connection conductors 5 extends upward from the outer diameter side end portion of each of the four protruding portions 42 and reaches the outer peripheral surface of the lower portion of the internal electrode 2. Each of the four connection conductors 5 extends upward from a position overlapping with the electrode support portion 7 in each of the four protruding portions 42 and passes through the inside of the electrode support portion 7. The outer peripheral surface of each of the four connection conductors 5 is covered by the electrode support portion 7. Male threads or female threads are formed at both ends of the connection conductor 5. Female threads or male threads are formed on each of the outer diameter side end portion of the protruding portion 42 and the outer peripheral surface of the lower portion of the internal electrode 2. By fitting the male threads or female threads formed at both ends of the connection conductor 5 with the female threads or male threads formed on each of the outer diameter side end portion of the protruding portion 42 and the outer peripheral surface of the lower portion of the internal electrode 2, the connection conductor 5 is fixed to each of the protruding portion 42 and the internal electrode 2.

[0058] The lightning protection device 1 further includes a lower insulating portion 65 (an example of the lower insulating portion). The lower insulating portion 65 is made of an insulator, for example, a reinforced plastic such as GFRP. The lower insulating portion 65 is at the upper ends of the columnar insulating portion 61 and the covering insulating portion 62, and is provided below the external electrode 3. The lower insulating portion 65 includes a protruding insulating portion 651 (an example of the protruding insulating portion of the lower insulating portion), an annular insulating portion 652 (an example of the annular insulating portion of the lower insulating portion), and a lower hole 653 (an example of the lower hole of the lower insulating portion).

[0059] The protruding insulating portion 651 is rod-shaped and protrudes in the outer diameter direction from the upper ends of the columnar insulating portion 61 and the covering insulating portion 62. The number of the protruding insulating portions 651 is plural, and here it is four. Each of the four protruding insulating portions 651 covers each of the four protruding portions 42 of the grounding conductor 4.

[0060] The annular insulating portion 652 is provided on the outer diameter side of the covering insulating portion 62. The annular insulating portion 652 is annular and connects each of the four protruding insulating portions 651. The annular insulating portion 652 connects, for example, the outer diameter side ends of each of the four protruding insulating portions 651.

[0061] The lower hole 653 is provided between each of the four protruding insulating portions 651. The number of the lower holes 653 is arbitrary, and here it is four. Each of the four lower holes 653 is connected to the central hole 33 at the lower part of the central hole 33. Each of the four lower holes 653 is composed of a part of the covering insulating portion 62, two linear protruding insulating portions 651, and a part of the annular annular insulating portion 652.

[0062] In addition, the configurations and lightning strike suppression functions of the lightning protection device 1 other than those described above in the present embodiment are the same as those of the lightning strike device in the first embodiment, so the description thereof will not be repeated.

[0063] According to the present embodiment, the same effects as those of the first embodiment can be obtained.

[0064] In addition, since the internal electrode 2 is supported by the connection conductor 5 from below, the internal electrode 2 can be stably fixed.

[0065] In addition, since the lower hole 653 is connected to the central hole 33, foreign matter that has fallen into the central hole 33 can be discharged to the outside of the lightning protection device 1 through the lower hole 653. Thereby, adhesion of foreign matter to the external electrode 3 can be suppressed.

[0066] [Others]

[0067] The above-described embodiments and modified examples can be combined as appropriate. In order to prevent a decrease in insulation due to an increase in the local potential gradient, in the above-described embodiments and modified examples, it is necessary that the lightning protection device 1 does not have a pointed portion as a whole.

[0068] The above-described embodiments and modified examples should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Description of Reference Numerals

[0069] 1 Lightning protection device (an example of a lightning strike suppression type lightning protection device) 2 Internal electrode (an example of an internal electrode) 2a, 2b Internal electrode portions 3 External electrode (an example of an external electrode) 3a, 3b External electrode portions (an example of the first and second external electrode portions) 4 Grounding conductor (an example of a grounding conductor) 5 Connection conductor (an example of a connection conductor) 7 Electrode support portion 21, 22 Outer peripheral surfaces of the internal electrode 31 Inner diameter side portion of the external electrode 32 Outer diameter side portion of the external electrode 33 Central hole of the external electrode (an example of the central hole of the external electrode) 34 Connection hole of the external electrode (an example of the connection hole of the external electrode) Upper end of the external electrode Lower end of the external electrode Columnar portion of the ground conductor (an example of the columnar portion of the ground conductor) Protruding portion of the ground conductor (an example of the protruding portion of the ground conductor) Columnar portion insulating part (an example of the columnar portion insulating part) Coating insulating part Upper insulating part (an example of the upper insulating part) Connecting conductor insulating part Lower insulating part (an example of the lower insulating part) Male thread of the coating insulating part Upper end of the upper insulating part Protruding portion insulating part of the lower insulating part (an example of the protruding portion insulating part of the lower insulating part) Annular insulating part of the lower insulating part (an example of the annular insulating part of the lower insulating part) Lower hole of the lower insulating part (an example of the lower hole of the lower insulating part) AX Central axis GR Ground surface IS Inside of the external electrode (an example of the inside of the external electrode) SP Object to be fixed

Claims

1. An internal electrode that is grounded, and an external electrode that is electrically insulated from the internal electrode and includes an interior that houses the internal electrode, wherein the internal electrode has an annular shape surrounding a central axis extending in the vertical direction, the external electrode has an annular shape surrounding the central axis, and the external electrode includes an inner diameter side portion facing an outer peripheral surface on the inner diameter side of the internal electrode and an outer diameter side portion facing an outer peripheral surface on the outer diameter side of the internal electrode, the lightning strike suppression type lightning arrester.

2. When viewed in a cross-section including the central axis, the external electrode, includes a first external electrode portion that is present on one side of the central axis and has an elliptical outer shape with a major axis in the vertical direction, and a second external electrode portion that is present on the other side of the central axis and has an elliptical outer shape with a major axis in the vertical direction, the lightning strike suppression type lightning arrester according to Claim 1.

3. The external electrode further includes a connection hole that connects the inside of the external electrode and the outside of the external electrode, a grounding conductor that is a grounded conductor, and further includes a connection conductor that penetrates the connection hole and electrically connects the grounding conductor and the internal electrode, the lightning strike suppression type lightning arrester according to Claim 1.

4. The grounding conductor includes a columnar portion extending along the central axis, each of the internal electrode and the external electrode surrounds the columnar portion, the connection hole is provided in the inner diameter side portion, and the connection conductor extends from the columnar portion and reaches an outer peripheral surface on the inner diameter side of the internal electrode, the lightning strike suppression type lightning arrester according to Claim 3.

5. The external electrode further includes a central hole surrounded by the inner diameter side portion, a columnar portion insulating portion covering at least a part of the outer peripheral surface of the columnar portion, and further includes an upper insulating portion provided on the columnar portion insulating portion and covering the central hole and an upper end portion of the external electrode, wherein when viewed in a cross-section including the central axis, a horizontal width of the upper insulating portion increases downward from an upper end portion of the upper insulating portion, the lightning strike suppression type lightning arrester according to Claim 4.

6. The grounding conductor, includes a columnar portion extending along the central axis, and a protruding portion protruding in the outer diameter direction from the columnar portion, and the connection conductor extends upward from the protruding portion and reaches the internal electrode, the lightning strike suppression type lightning arrester according to Claim 3.

7. The external electrode includes a central hole surrounded by the inner diameter side portion, a columnar portion insulating portion covering at least a part of the outer peripheral surface of the columnar portion, and further includes a lower insulating portion provided at a lower portion of the external electrode, The lower insulating portion is a plurality of protruding insulating portions that protrude from the columnar insulating portion in the outer diameter direction and cover the protruding portions, an annular insulating portion provided on the outer diameter side of the columnar insulating portion and connecting each of the plurality of protruding insulating portions, The lightning strike suppression type lightning arrester according to claim 6, comprising a lower hole provided between each of the plurality of protruding insulating portions and connected to the central hole.

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