Lightning suppression type lightning protection device

Abstract

To provide a lightning suppression type surge arrester that has excellent isotropic lightning protection performance and can be easily installed. To provide a lightning suppression type surge arrester that allows for easy adjustment of the dielectric strength. [Solution] The lightning arrester 1, which is a lightning suppression type lightning arrester, comprises an internal electrode 2 that is grounded, and an external electrode 3 that is electrically insulated from the internal electrode 2 and includes an internal IS that houses the internal electrode 2. The internal electrode 2 has an annular shape surrounding a central axis AX that extends 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 that faces the inner diameter side outer peripheral surface 21 of the internal electrode 2, and an outer diameter side portion 31 that faces the outer diameter side outer peripheral surface 22 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, and small particles are charged with positive charges and 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 discharged to the ground surface through the lightning rod, ensuring the safety around the lightning rod (In the case of winter lightning, the updraft is not as strong as in summer, so it is considered that the lower particles (heavy graupel, etc.) carrying negative charges fall in a short time, and only the upper positive charge particles remain. Therefore, positive charges gather below the clouds and the polarities of the cloud bottom and the ground surface are reversed. Therefore, the polarity in the corresponding description of this case should be read as reversed).

[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 interposed 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 gathered below approaches, positive charges opposite thereto are induced on the ground surface and 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 suppression type surge arresters are disclosed, for example, in the following Patent Documents 1 and 2. Patent Document 1 discloses a lightning suppression type surge arrester comprising an inner electrode body that is grounded, an outer electrode body that is provided so as to enclose the inner electrode body with a predetermined gap, an electrical insulating layer provided in the gap to keep the inner electrode body and the outer electrode body in an electrically insulating state, and a support that supports at least one of the inner electrode body and the outer electrode body, wherein the inner electrode body is formed in the shape of a rod and the outer electrode body is formed in the shape of a cylinder. This lightning suppression type surge arrester is provided in an elongated form to surround the entire circumference of the periphery of the roof of a building.

[0005] Patent Document 2 discloses a lightning suppression type lightning arrester comprising a grounded second electrode body, a first electrode body provided so as to enclose the second electrode body with a predetermined gap, and an electrical insulating layer provided in the gap to maintain an electrically insulating state between the second electrode body and the first electrode body. The second electrode body has a substantially spherical shape, and 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 covered almost entirely by the first electrode body. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2018-10737 (Specification of Japanese Patent No. 6028293) [Patent Document 2] Japanese Patent Publication No. 2018-67519 (Specification of Japanese Patent No. 6128539) [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In the lightning suppression type surge arrester described in Patent Document 1, the outer electrode body extends in a straight line when viewed from above, resulting in lower lightning protection performance in the direction perpendicular to the extension direction compared to the lightning protection performance in the direction of extension of the outer electrode body. Therefore, the technology in Patent Document 1 had the problem of poor isotropy in lightning protection performance. In addition, the fall suppression type surge arrester in Patent Document 1 needs to be installed around the entire perimeter of the rooftop of a building in a long form, which presents problems in terms of weight, size, and cost, making installation difficult.

[0008] In the lightning suppression type surge arrester described in Patent Document 2, both the first and second electrode bodies are made of spherical surfaces, and the distance between the first and second electrode bodies is uniform throughout. Therefore, in order to increase the dielectric strength of the lightning suppression type surge arrester described in Patent Document 2, it was necessary to increase the diameter of the first electrode body and enlarge the entire first electrode body in order to uniformly move it away from the second electrode body throughout. For this reason, the lightning suppression type surge arrester described in Patent Document 2 had the problem that it was not easy to adjust the dielectric strength.

[0009] The present invention aims to solve the above problems, and one of its objectives is to provide a lightning suppression type lightning protection device that has excellent isotropic lightning protection performance and can be easily installed.

[0010] Another object of the present invention is to provide a lightning suppression type lightning arrester that allows for easy adjustment of the dielectric strength. [Means for solving the problem]

[0011] A lightning suppression type lightning protection device according to one aspect of the present invention comprises an internal electrode that is grounded, and an external electrode electrically insulated from the internal electrode, the external electrode including an interior that houses the internal electrode, wherein the internal electrode has an annular shape surrounding a central axis extending in the vertical direction, and the external electrode has an annular shape surrounding a 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] Preferably, in the above-described lightning suppression type lightning arrester, when viewed in a cross-section including the central axis, the external electrode includes a first external electrode portion located on one side of the central axis and having an elliptical shape with a major axis in the vertical direction, and a second external electrode portion located on the other side of the central axis and having an elliptical shape with a major axis in the vertical direction.

[0013] Preferably, in the above-described lightning suppression type lightning arrester, the external electrode further includes a connection hole that connects the inside of the external electrode to the outside of the external electrode, and further comprises a grounding conductor which is a grounded conductor, and a connecting conductor which penetrates the connection hole and electrically connects the grounding conductor and the internal electrode.

[0014] Preferably, in the above-described lightning suppression type lightning arrester, 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 portion, and the connecting conductor extends from the columnar portion and reaches the outer peripheral surface on the inner diameter side of the internal electrode.

[0015] Preferably, in the above-described lightning suppression type lightning arrester, the external electrode further includes a central hole surrounded by an inner diameter portion, a columnar insulating portion that covers at least a part of the outer circumferential surface of the columnar portion, and an upper insulating portion provided on the columnar insulating portion that covers the central hole and the upper end of the external electrode, wherein, when viewed in a cross-section including the central axis, the horizontal width of the upper insulating portion increases downward from the upper end of the upper insulating portion.

[0016] In the above-described lightning suppression type lightning arrester, the grounding conductor preferably includes a columnar portion extending along the central axis and a projection portion projecting outward from the columnar portion, and the connecting conductor extends upward from the projection portion and reaches the internal electrode.

[0017] In the lightning strike suppression type lightning arrester described above, preferably, the external electrode includes a central hole surrounded by an inner diameter side portion, a columnar portion insulator covering at least a part of the outer peripheral surface of the columnar portion, and a lower insulator provided at the lower part of the external electrode. The lower insulator further includes a plurality of protruding portion insulators protruding in the outer diameter direction from the columnar portion insulator and covering the protruding portions, an annular insulating portion provided on the outer diameter side of the columnar portion insulator and connecting each of the plurality of protruding insulating portions, and a lower hole provided between each of the plurality of protruding portion insulators and connected to the central hole.

Effect of the Invention

[0018] According to the present invention, it is possible to provide a lightning strike suppression type lightning arrester having excellent isotropy of lightning protection performance and being easily installed. Further, according to the present invention, it is possible to provide a lightning strike suppression type lightning arrester in which the adjustment of the insulation breakdown voltage is easy.

Brief Description of the Drawings

[0019] [Figure 1] It is a cross-sectional view showing the configuration of the lightning arrester 1 in the first embodiment of the present invention, and is a cross-sectional view when cut by a plane orthogonal to the central axis AX. [Figure 2] It is a cross-sectional view taken along line II-II in FIG. 1. [Figure 3] It is a cross-sectional view taken along line III-III in FIG. 1. [Figure 4] It is a diagram for explaining the lightning strike suppression function by the lightning arrester 1 in the first embodiment of the present invention. [Figure 5] It is a cross-sectional view showing the configuration of the lightning arrester 1 in the second embodiment of the present invention, and is a cross-sectional view when cut by a plane orthogonal to the central axis AX. [Figure 6] It is a cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] It is a cross-sectional view taken along line VII-VII in FIG. 5. [Figure 8] It is a cross-sectional view showing the configuration near the lower insulator 65 of the lightning arrester 1 in the second embodiment of the present invention, and is a cross-sectional view taken along line VIII-VIII in FIG. 6. [Figure 9]This is an external view of the lightning protection device 1 when viewed from the horizontal direction in the second embodiment of the present invention. [Figure 10] This is an external view of the lightning protection device 1 when viewed obliquely downward in the second embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0021] [First Embodiment]

[0022] FIG. 1 is a cross-sectional view showing the configuration of the lightning protection device 1 in the first embodiment of the present invention, and 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 portion insulating portion 61 (an example of a columnar portion 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 via a grounding conductor 4 and a connecting conductor 5. The internal electrode 2 has an annular shape surrounding the central axis AX. When viewed in a cross-section including the central axis AX (cross-section in Figures 2 and 3), the internal electrode 2 preferably has an elliptical cross-sectional shape, and more preferably has an elliptical cross-sectional shape with a major axis in the vertical direction. This reduces the number of pointed parts in the internal electrode 2, thereby suppressing the concentration of charge on the pointed parts. 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 opposite side from the central axis AX.

[0025] Furthermore, when viewed in a cross-section including the central axis AX, the internal electrode 2 includes an internal electrode portion 2a located on one side of the central axis AX (left side in Figures 2 and 3) and having an elliptical shape with a major axis in the vertical direction, and an internal electrode portion 2b located on the other side of the central axis AX (right side in Figures 2 and 3) and having 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 interior 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 also be filled with a solid insulator. The external electrode 3 has an annular shape surrounding a central axis AX, and for example, it has a torus shape (a shape composed of a plane of rotation obtained by rotating around a circle).

[0027] The external electrode 3 includes an inner diameter portion 31 (an example of an inner diameter portion), an outer diameter portion 32 (an example of an outer diameter 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 changes continuously along the inner circumferential surface of the external electrode 3 as shown in Figure 3.

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

[0029] The outer diameter portion 32 is the portion that faces 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 and surrounded by the inner diameter 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 holes 34 connect the internal IS of the external electrode 3 to the outside of the external electrode 3. The connection holes 34 are provided in the inner diameter portion 31. The number of connection holes 34 is arbitrary, and there are two in this case. Each of the two connection holes 34 is provided in an opposing position on either side of the portion near the upper end of the columnar portion 41 in the inner diameter portion 31.

[0032] The internal IS of the external electrode 3 and the external area of ​​the external electrode 3 are separated by the inner diameter portion 31 and the outer diameter portion 32.

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

[0034] The external electrode portion 3a houses the internal electrode portion 2a within the internal IS. The inner diameter portion 31 of the external electrode portion 3a faces the inner diameter outer circumferential surface 21 of the internal electrode portion 2a. The outer diameter portion 32 of the external electrode portion 3a faces the outer diameter outer circumferential surface 22 of the internal electrode portion 2a.

[0035] The external electrode portion 3b houses the internal electrode portion 2b within the internal IS. The inner diameter portion 31 of the external electrode portion 3b faces the inner diameter outer circumferential surface 21 of the internal electrode portion 2b. The outer diameter portion 32 of the external electrode portion 3b faces the outer diameter outer circumferential surface 22 of the internal electrode portion 2b.

[0036] When viewed in a cross-section including the central axis AX, it is preferable that each of the external electrode portions 3a and 3b has a shape in which the horizontal width of each external electrode portion 3a and 3b increases downward from the upper end portion 35 of each external electrode portion 3a and 3b. This makes it easier for foreign matter such as bird droppings to fall off the external electrode 3 due to its own weight, thereby preventing foreign matter from adhering to the external electrode 3. Furthermore, when viewed in a cross-section including the central axis AX, it is more preferable that each of the external electrode portions 3a and 3b has an elliptical shape with a major axis in the vertical direction. This makes it possible to avoid the formation of sharp parts on the external electrode 3 and prevents localized concentration of negative charge on the external electrode 3.

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

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

[0039] The connecting conductor 5 is made of a conductor and electrically connects the ground conductor 4 and the internal electrode 2. The number of connecting conductors 5 is arbitrary, but here there are two. Each of the two connecting conductors 5 extends horizontally and passes through each of the two connecting holes 34. Each of the two connecting conductors 5 extends from the outer circumferential surface of the columnar portion 41 and reaches the outer circumferential surface 21 on the inner diameter side of the internal electrode 2. Male or female threads are formed at both ends of the connecting conductor 5. Female or male threads are formed on the outer circumferential surface of the columnar portion 41 and the outer circumferential surface 21 on the inner diameter side of the internal electrode 2. The connecting conductor 5 is fixed to the columnar portion 41 and the internal electrode 2 by fitting together the male or female threads formed at both ends of the connecting conductor 5 with the female or male threads formed on the outer circumferential surface of the columnar portion 41 and the outer circumferential surface 21 on the inner diameter side of the internal electrode 2.

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

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

[0042] The covering insulation portion 62 covers a part of the outer circumferential surface of the columnar insulation portion 61. The upper end of the covering insulation portion 62 may extend in the radial direction near the lower part of the external electrode 3. Male threads 621 are formed at the lower ends of the columnar insulation portions 61 and 62. The lightning arrester 1 is fixed to the object SP by fitting the male threads 621 formed at the lower ends of the columnar insulation portions 61 and 62 with the female threads formed on the object SP to be fixed. The covering insulation portion 62 may be integrated with the columnar insulation portion 61.

[0043] The upper insulating portion 63 is provided at the upper end of the columnar insulating portion 61. The upper insulating portion 63 covers the central hole 33 and the upper end 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 631 of the upper insulating portion 63. The upper end 631 of the upper insulating portion 63 is located in a position that coincides with the central axis AX and is preferably rounded.

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

[0045] The electrode support portion 7 is made of an insulator and insulates the internal electrode 2 from the external electrode 3 while fixing the internal electrode 2 to the inside IS of the external electrode 3. The shape of the electrode support portion 7 is arbitrary, but here it is four columnar shapes. Each of the four electrode support portions 7 is positioned at four equally spaced positions on the circumference of a circle centered on the central axis AX. Each of the four electrode support portions 7 extends upward from the inner circumferential 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 part of the electrode support portion 7 by passing the internal electrode 2 through a hole provided in the upper part 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 inner diameter side outer circumferential surface 21 and the outer diameter side outer circumferential surface 22 of the internal electrode 2 with the U-shaped upper end portion of the electrode support portion 7.

[0046] Figure 4 is a diagram illustrating the lightning strike suppression function of the lightning protection device 1 in the first embodiment of the present invention.

[0047] Referring to Figure 4, when a cloud CL forms, positive charges accumulate above the cloud CL and negative charges accumulate below the cloud CL. When negative charges accumulate below the cloud CL, the opposite positive charges are induced on the ground surface GR. Since the grounding conductor 4, connecting conductor 5, and internal electrode 2 are grounded, positive charges also accumulate on the grounding conductor 4, connecting conductor 5, and internal electrode 2. The external electrode 3 faces the internal electrode 2 across the insulating space IS, so when the internal electrode 2 becomes positively charged, the external electrode 3 becomes negatively charged due to the capacitor effect. This action makes it less likely for lightning to strike the external electrode 3, and the occurrence of lightning strikes on the lightning arrester 1 itself and its surroundings is suppressed.

[0048] In this embodiment, both the internal electrode 2 and the external electrode 3 have an annular shape surrounding a central axis extending vertically. This allows for the accumulation of a nearly uniform amount of charge on the external electrode 3 in all directions relative to the central axis AX. As a result, it becomes a lightning suppression type lightning arrester with excellent isotropic lightning protection performance. The external electrode 3 also includes an inner diameter side portion 31 facing the inner diameter side outer peripheral surface 21 of the annular internal electrode 2, and an outer diameter side portion 32 facing the outer diameter side outer peripheral surface 22 of the internal electrode 2. This increases the area of ​​the portion of the external electrode 3 facing the internal electrode 2, thereby increasing the area of ​​the external electrode capable of accumulating negative charge. As a result, lightning protection performance can be improved. Furthermore, it is not necessary to install a lightning arrester around the entire circumference of the rooftop of a building in a long-length configuration, making it easy to install the lightning arrester. Furthermore, since neither the internal electrode 2 nor the external electrode 3 are spherical, even when increasing the dielectric strength of the lightning arrester, it is not necessary to uniformly distance the external electrode 3 from the internal electrode 2 throughout the entire device, nor is it necessary to enlarge the external electrode 3 as a whole. Therefore, the dielectric strength can be easily adjusted.

[0049] Furthermore, since the external electrode 3 includes external electrode portions 3a and 3b that have 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 convex shape that points upward. As a result, foreign matter attached to each of the external electrode portions 3a and 3b is more likely to fall off due to gravity. In addition, because each of the external electrode portions 3a and 3b has an elliptical cross-sectional shape, pointed parts are less likely to form on the external electrode 3 when viewed in a cross-section including the central axis, and areas where charge is locally concentrated on the external electrode 3 are less likely to form. As a result, a decrease in lightning protection performance can be suppressed.

[0050] Furthermore, since the external electrode 3 includes a connection hole 34 and the connecting conductor 5 passes through the connection hole 34, it becomes easy to electrically connect the grounding conductor 4 and the internal electrode 2.

[0051] Furthermore, by providing an upper insulating portion 63 that covers the central hole 33 and the upper end portion 35 of the external electrode 3, it is possible to prevent foreign matter from adhering to the upper part of the external electrode 3.

[0052] [Second Embodiment]

[0053] Figure 5 is a cross-sectional view showing the configuration of the lightning arrester 1 in the second embodiment of the present invention, and is a cross-sectional view taken when cut by a plane perpendicular to the central axis AX. Figure 6 is a cross-sectional view along the line VI-VI in Figure 5. Figure 7 is a cross-sectional view along the line VII-VII in Figure 5. Figure 8 is a cross-sectional view showing the configuration near the lower insulating part 65 of the lightning arrester 1 in the second embodiment of the present invention, and is a cross-sectional view along the line VIII-VIII in Figure 6. Figure 9 is an external view of the lightning arrester 1 as seen from the horizontal direction in the second embodiment of the present invention. Figure 10 is an external view of the lightning arrester 1 as seen from diagonally below in the second embodiment of the present invention. Figure 5 corresponds to a cross-sectional view along the line VV in Figure 6.

[0054] Referring to Figures 5 to 10, in the lightning arrester 1 of this 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 internal IS of the external electrode 3 to the outside of the external electrode 3. The number of connection holes 34 is arbitrary, and in this case there are four. Each of the four connection holes 34 is provided at equal intervals along the annular lower end portion 36.

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

[0056] The protrusions 42 project outward from the columnar portion 41. The number of protrusions 42 is arbitrary, and in this case there are four. Each of the four protrusions 42 is provided at equal intervals along the outer circumference of the columnar portion 41 and extends to the vicinity of the lower end 36 of the external electrode 3.

[0057] The connecting conductors 5 are made of a conductor and electrically connect the ground conductor 4 and the internal electrode 2. The number of connecting conductors 5 is arbitrary, and here there are four. Each of the four connecting conductors 5 extends vertically and passes through each of the four connecting holes 34. Each of the four connecting conductors 5 extends upward from the outer diameter end of each of the four protrusions 42 and reaches the lower outer circumferential surface of the internal electrode 2. Each of the four connecting conductors 5 extends upward from a position overlapping with the electrode support 7 at each of the four protrusions 42 and passes through the interior of the electrode support 7. The outer circumferential surface of each of the four connecting conductors 5 is covered by the electrode support 7. Male or female threads are formed at both ends of the connecting conductors 5. Female or male threads are formed at the outer diameter end of the protrusions 42 and at the lower outer circumferential surface of the internal electrode 2. The connecting conductor 5 is fixed to the protruding portion 42 and the internal electrode 2 by fitting together male or female threads formed at both ends of the connecting conductor 5 with female or male threads formed at the outer diameter end of the protruding portion 42 and the outer peripheral surface of the lower part of the internal electrode 2.

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

[0059] The protruding insulating portion 651 is rod-shaped and protrudes radially outward from the upper ends of the columnar insulating portion 61 and the covering insulating portion 62. There are multiple protruding insulating portions 651, and in this case there are 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 end of each of the four protruding insulating portions 651.

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

[0062] Furthermore, the configuration of the lightning protection device 1 in this embodiment, other than those described above, and its lightning suppression function are the same as those of the lightning protection device in the first embodiment, so their explanation will not be repeated.

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

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

[0065] Furthermore, since the lower hole 653 is connected to the central hole 33, foreign objects that fall into the central hole 33 can be discharged to the outside of the lightning arrester 1 through the lower hole 653. This prevents foreign objects from adhering to the external electrode 3.

[0066] [others]

[0067] The embodiments and modifications described above can be combined as appropriate. In order to prevent a decrease in insulation performance due to a rise in local potential gradients, in the embodiments and modifications described above, the lightning arrester 1 must not have any sharp parts throughout.

[0068] The embodiments and modifications described above should be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0069] 1. Lightning protection device (an example of a lightning suppression type lightning protection device) 2. Internal electrodes (an example of internal electrodes) 2a,2b Internal electrode part 3. External electrodes (an example of an external electrode) 3a, 3b External electrode section (Examples of the first and second external electrode sections) 4. Grounding conductor (an example of a grounding conductor) 5. Connecting conductors (an example of a connecting conductor) 7 Electrode support part 21,22 Outer surface of the internal electrode 31 Inner diameter portion of the external electrode 32 Outer diameter portion of the external electrode 33. Central hole of an external electrode (an example of a central hole of an external electrode) 34. Connection holes for external electrodes (an example of connection holes for external electrodes) 35 Upper end of external electrode 36 Lower end of external electrode 41. Columnar portion of a grounding conductor (an example of a columnar portion of a grounding conductor) 42. Protruding part of the grounding conductor (an example of a protruding part of the grounding conductor) 61. Columnar section insulation (an example of a columnar section insulation) 62 Covered insulating part 63 Upper insulating section (an example of an upper insulating section) 64 Insulation of connecting conductor 65 Lower insulation section (an example of a lower insulation section) 621 Male screw for insulated part 631 Upper end of upper insulation 651 Insulated portion of the protruding part of the lower insulation section (an example of an insulated portion of the protruding part of the lower insulation section) 652 Annular insulating portion of the lower insulating section (an example of an annular insulating portion of the lower insulating section) 653 Lower hole in the lower insulation section (an example of a lower hole in the lower insulation section) AX center axis GR surface IS external electrode interior (an example of the internal structure of an external electrode) SP Fixed Object

Claims

1. The internal electrode is grounded, An external electrode electrically insulated from the internal electrode, comprising an external electrode including an interior that houses the internal electrode, The internal electrode has an annular shape surrounding a central axis that extends in the vertical direction. The external electrode has an annular shape surrounding the central axis, The lightning protection device comprises an external electrode including an inner diameter portion facing the inner diameter outer surface of the internal electrode and an outer diameter portion facing the outer diameter outer surface of the internal electrode.

2. When viewed in a cross-section including the central axis, the external electrode is A first external electrode portion located on one side of the central axis and having an elliptical shape with a major axis in the vertical direction, The lightning suppression type lightning protection device according to claim 1, further comprising a second external electrode portion located on the other side of the central axis and having an elliptical outer shape with a major axis in the vertical direction.

3. The external electrode further includes a connection hole that connects the inside of the external electrode to the outside of the external electrode, A grounding conductor is a conductor that is grounded, The lightning suppression type lightning protection device according to claim 1, further comprising a connecting conductor that penetrates the connecting hole and electrically connects the grounding conductor and the internal electrode.

4. The grounding conductor includes a columnar portion extending along the central axis, Each of the internal and external electrodes surrounds the columnar portion, The connection hole is provided in the inner diameter portion, The lightning suppression type lightning protection device according to claim 3, wherein the connecting conductor extends from the columnar portion and reaches the outer peripheral surface on the inner diameter side of the internal electrode.

5. The external electrode further includes a central hole surrounded by the inner diameter portion, A columnar insulating portion that covers at least a part of the outer surface of the columnar portion, The columnar insulating portion is further provided with an upper insulating portion that covers the central hole and the upper end of the external electrode, The lightning suppression type lightning protection device according to claim 4, wherein, when viewed in a cross-section including the central axis, the horizontal width of the upper insulating portion increases downward from the upper end of the upper insulating portion.

6. The aforementioned grounding conductor is A columnar portion extending along the aforementioned central axis, The columnar portion includes a protruding portion that extends outward in the diametrical direction, The lightning suppression type lightning protection device according to claim 3, wherein the connecting conductor extends upward from the protruding portion and reaches the internal electrode.

7. The external electrode includes a central hole surrounded by the inner diameter portion, A columnar insulating portion that covers at least a part of the outer surface of the columnar portion, The external electrode further comprises a lower insulating portion provided at the lower part of the external electrode, The aforementioned lower insulating portion is Multiple protruding portion insulating portions that protrude outward from the columnar portion insulating portion and cover the protruding portion, An annular insulating portion is provided on the outer diameter side of the columnar insulating portion and connects each of the plurality of protruding insulating portions, The lightning suppression type lightning protection device 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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