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 comprises an internal electrode 2 that is grounded, and an external electrode 3 which is electrically insulated from the internal electrode 2 and includes an internal IS that houses the internal electrode 2. The internal electrode 2 includes a flat plate portion 21 which has a circular shape around a central axis AX when viewed from above. The external electrode 3 includes a flat plate portion 31 which faces the upper surface 221 of the flat plate portion 21 and has a circular shape around a central axis AX when viewed from above, and a flat plate portion 32 which faces the lower surface of the flat plate portion 21 and has a circular shape around a central axis AX when viewed from above.

Description

Technical Field

[0001] The present invention relates to a lightning strike suppression type lightning protection device. More specifically, it relates to a lightning strike suppression type lightning protection device that has excellent isotropy of lightning protection performance and can suppress the degradation of lightning protection performance.

Background Art

[0002] When clouds form, dust and ice particles in the clouds collide with each other, causing small particles to become positively charged and large particles to become negatively charged. Positive charges gather above the cloud, and negative charges gather below the cloud. When negative charges gather below the cloud, positive charges are induced on the ground surface, and the negative charges gathered below the cloud are attracted to the positive charges on the ground surface, resulting in a lightning strike. A general lightning rod includes a grounded pointed tip, which concentrates positive charges at this tip. As a result, the negative charges gathered below the cloud are safely discharged 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 positively charged particles remain. Therefore, positive charges gather below the cloud, and the polarity between the cloud bottom and the ground surface is reversed. So, the polarity in the relevant 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 sandwiched 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 to it are induced on the ground surface and attracted to the positive charges on the ground surface, causing positive charges to also gather on the first electrode. Then, due to the action of a capacitor, the second electrode becomes negatively charged. By this action, it becomes difficult for lightning to strike the second electrode, and the occurrence of lightning strikes on the 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 that is electrically insulated from the internal electrode and includes an interior that houses the internal electrode, wherein the internal electrode includes a flat plate-shaped internal plate electrode having a circular shape about a central axis when viewed from above, and the external electrode includes a flat plate-shaped upper plate electrode facing the upper surface of the internal plate electrode and having a circular shape about a central axis when viewed from above, and a flat plate-shaped lower plate electrode facing the lower surface of the internal plate electrode and having a circular shape about a central axis when viewed from above.

[0012] Preferably, in the above-described lightning suppression type lightning arrester, the internal electrode further includes a projection provided at the outer diameter side end of the internal flat plate electrode, the projection being an electrode that protrudes from the internal flat plate electrode in at least one of the directions upward and downward, and the minimum distance between the internal electrode and the external electrode is defined by the distance between the projection and the upper flat plate electrode or the lower flat plate electrode.

[0013] Preferably, in the above-described lightning suppression type lightning arrester, the protruding portion is spherical, and the external electrode further includes an arc-shaped portion provided on the outer diameter side of the protruding portion, the arc-shaped portion connecting the upper flat plate electrode and the lower flat plate electrode, and being arc-shaped when viewed in a cross-section including the central axis, and protruding in the outer diameter direction with respect to the central axis.

[0014] Preferably, in the above-described lightning suppression type lightning arrester, the external electrode further includes a central hole provided at a position including the central axis of the lower plate electrode, the central hole is a conductor that connects the inside of the external electrode to the outside of the external electrode and is grounded, and further includes a grounding conductor that is electrically connected to the internal electrode, the grounding conductor includes a support column that extends along the central axis, the support column passing through the central hole to reach the internal electrode.

[0015] Preferably, the above-described lightning suppression type lightning arrester further includes an insulating portion that insulates the support column from the external electrode, the insulating portion including a first insulating portion that includes an upper surface in contact with the lower surface of the lower flat plate electrode and covers the outer circumferential surface of the support column, and a second insulating portion provided inside the central hole and inside the external electrode and covering the outer circumferential surface of the support column, wherein the horizontal width of the second insulating portion is greater than the horizontal width of the first insulating portion.

[0016] Preferably, the above-described lightning suppression type lightning protection device further comprises a convex member that covers the upper flat plate electrode and has a convex shape that protrudes upward when viewed in a cross-section including the central axis. [Effects of the Invention]

[0017] 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 adjustment of the insulation breakdown voltage is easy.

Brief Description of the Drawings

[0018] [Figure 1] It is a perspective view showing the configuration of the lightning protection device 1 in one embodiment of the present invention. [Figure 2] It is a cross-sectional view taken along line II-II in FIG. 1. [Figure 3] It is a diagram for explaining the lightning strike suppression function by the lightning protection device 1 in one embodiment of the present invention. [Figure 4] It is a cross-sectional view showing the configuration of a modified example of the lightning protection device 1 in one embodiment of the present invention.

Modes for Carrying Out the Invention

[0019] Hereinafter, one embodiment of the present invention will be described based on the drawings.

[0020] FIG. 1 is a perspective view showing the configuration of the lightning protection device 1 in one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. In FIG. 2, the upper direction is up and the lower direction is down.

[0021] Referring to FIGS. 1 and 2, 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 a negatively charged electrode, and mainly 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), and an insulating portion 5 (an example of an insulating portion). The lightning protection device 1 has a virtual central axis AX (an example of a central axis) extending in the vertical direction.

[0022] The internal electrode 2 is made of a conductor such as titanium and is grounded through the ground conductor 4 or the like. The internal electrode 2 includes a flat plate portion 21 (an example of an internal flat plate electrode) and a protruding portion 22 (an example of a protruding portion).

[0023] The flat plate portion 21 is a flat plate extending in the horizontal direction. When viewed from above, the flat plate portion 21 has a circular shape with a central axis AX. The flat plate portion 21 includes an upper surface 211 and a lower surface 212. The upper surface 211 is planar and faces upward. The lower surface 212 is planar and faces downward.

[0024] The protrusion 22 is provided at the outer diameter end of the flat plate portion 21. The protrusion 22 is an electrode that protrudes from the flat plate portion 21 in at least one of the directions of upward and downward. Here, the flat plate electrode is spherical when viewed in a cross-section including the central axis AX (cross-section in Figure 2) and protrudes from the flat plate portion 21 in both upward and downward directions.

[0025] Incidentally, if the distance between the internal electrode 2 and the external electrode 3 is too close, internal discharge is more likely to occur. On the other hand, if the distance between the internal electrode 2 and the external electrode 3 is too far, it becomes difficult for charge to accumulate on the external electrode 3, making it more susceptible to lightning strikes. By providing the protrusion 22, the minimum distance between the internal electrode 2 and the external electrode 3 is more easily determined by the distance d between the protrusion 22 and the flat plate portion 31 or 32. This makes it possible to appropriately adjust the distance between the internal electrode 2 and the external electrode 3, thereby avoiding the problems of internal discharge and the difficulty in accumulating charge on the external electrode. Here, the distance between the protrusion 22 and the flat plate portion 31 and the distance between the protrusion 22 and the flat plate portion 32 are both distance d and are equal.

[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 external electrode 3 includes a flat plate portion 31 (an example of an upper flat plate electrode), a flat plate portion 32 (an example of a lower flat plate electrode), an arc-shaped portion 33 (an example of an arc-shaped portion), a central hole 34 (an example of a central hole), and a ventilation hole 35.

[0027] The interior IS of the external electrode 3 and the exterior of the external electrode 3 are separated by the flat plate portions 31 and 32 and the arc-shaped portion 33. The interior IS of the external electrode 3 may be filled with an insulator.

[0028] The flat plate portion 31 is a flat plate extending in the horizontal direction. When viewed from above, the flat plate portion 31 has a circular shape centered on the central axis AX. The flat plate portion 31 includes an upper surface 311 and a lower surface 312. The upper surface 311 is planar and faces upward. The upper surface 311 is exposed to the outside of the lightning arrester 1. The lower surface 312 is planar and faces downward. The lower surface 312 faces the upper surface 211 of the flat plate portion 21 and extends almost parallel to the upper surface 211 of the flat plate portion 21.

[0029] The flat plate portion 32 is a flat plate extending horizontally and faces the lower surface 212 of the flat plate portion 21. When viewed from above, the flat plate portion 32 has a circular shape centered on the central axis AX. The flat plate portion 32 includes an upper surface 321 and a lower surface 322. The upper surface 321 is planar and faces upward. The upper surface 321 faces the lower surface 212 of the flat plate portion 21 and extends approximately parallel to the lower surface 212 of the flat plate portion 21. The lower surface 322 is planar and faces downward. The lower surface 322 is exposed to the outside of the lightning arrester 1.

[0030] The arc-shaped portion 33 is arc-shaped when viewed in a cross-section including the central axis AX. The arc-shaped portion 33 connects the flat plate portion 31 and the flat plate portion 32. The arc-shaped portion 33 is provided on the outer diameter side of the projection portion 22, separated from the internal IS of the external electrode 3. The arc-shaped portion 33 connects the respective outer diameter ends of the flat plate portions 31 and 32. The arc-shaped portion 33 protrudes in the outer diameter direction with respect to the central axis AX. The arc-shaped portion 33 includes an inner circumferential surface 331 and an outer circumferential surface 332. The inner circumferential surface 331 is arc-shaped, recessed in the outer diameter direction with respect to the central axis AX. The inner circumferential surface 331 faces the outer circumferential surface 221 on the outer diameter side of the projection portion 22, separated from the internal IS of the external electrode 3. The outer circumferential surface 332 is arc-shaped, protruding in the outer diameter direction with respect to the central axis AX. The outer circumferential surface 332 is exposed to the outside of the lightning arrester 1. The upper end portion 3321 of the outer peripheral surface 332 is located above the upper surface 311 of the flat plate portion 31. The lower end portion 3322 of the outer peripheral surface 332 is located above the lower surface 322 of the flat plate portion 32. The outer peripheral surface 332 connects to the upper surface 311 of the flat plate portion 31 at a position on the inner diameter side of the upper end portion 3321. The outer peripheral surface 332 connects to the lower surface 322 of the flat plate portion 32 at a position on the inner diameter side of the lower end portion 3322. The minimum distance between the arc-shaped portion 33 and the internal electrode 2 is different from the minimum distance between each of the flat plate portions 31 and 32 and the internal electrode 2 (i.e., distance d), and is preferably greater than the minimum distance between each of the flat plate portions 31 and 32 and the internal electrode 2.

[0031] The central hole 34 is located in the flat plate portion 32 at a position including the central axis AX. The central hole 34 penetrates the flat plate portion 32 and connects the inside IS of the external electrode 3 to the outside of the external electrode 3.

[0032] The ventilation hole 35 connects the internal IS of the external electrode 3 to the outside of the external electrode 3. If air is present in the internal IS of the external electrode 3, and lightning strikes the lightning arrester 1, the current flowing through the lightning arrester 1 will cause the air in the internal IS of the external electrode 3 to expand, raising concerns that the pressure in the internal IS of the external electrode 3 will increase rapidly. By providing the ventilation hole 35, the pressure in the internal IS of the external electrode 3 can be reduced if it is higher than the pressure outside the external electrode 3. This prevents the lightning arrester 1 from being damaged due to a rapid increase in the internal IS of the external electrode 3. The ventilation hole 35 can be provided at any position on the external electrode 3. In this case, the ventilation hole 35 is provided at a position on the outer diameter side of the central hole 34 in the flat plate portion 32.

[0033] 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. The grounding conductor 4 includes support columns 41 and 42 (examples of support columns). Each of the support columns 41 and 42 is, for example, cylindrical. The support columns 41 and 42 extend along the central axis AX and penetrate the central hole 34 of the external electrode 3 to reach the internal electrode 2. The support column 41 is located below the external electrode 3. The lower part of the support column 41 is fixed to an object to be fixed, such as a building, and grounded. The support column 42 is located inside the central hole 34 and inside IS of the external electrode 3. The support column 42 connects the upper end of the support column 41 to the lower surface 212 of the flat plate portion 21. The internal electrode 2 is fixed to the upper end of the support column 42. The horizontal width of the support column 42 is smaller than the horizontal width of the support column 41.

[0034] The insulating part 5 is made of an insulator, for example, a reinforced plastic such as GFRP (Glass Fiber Reinforced Plastic). The insulating part 5 insulates the support columns 41 and 42 from the external electrode 3. The insulating part 5 includes an insulating part 51 (an example of a first insulating part) and an insulating part 52 (an example of a second insulating part). The insulating part 51 is exposed to the outside of the lightning arrester 1. The insulating part 51 is exposed to the outside of the lightning arrester 1 and covers the outer peripheral surface of the upper part of the support column 41. The insulating part 51 may cover the outer peripheral surface of the entire support column 41. The insulating part 51 includes an upper surface 511 that contacts the lower surface 322 of the flat plate part 32. The horizontal width of the insulating part 51 is greater than the horizontal width of the insulating part 52. The insulating part 52 is provided above the insulating part 51 and is provided inside the central hole 34 and inside IS of the external electrode 3. The insulating portion 52 covers the outer circumferential surface of the support column 42. The insulating portion 52 includes an upper surface 521 that contacts the lower surface 212 of the flat plate portion 21, and an outer circumferential surface 522 that contacts the inner circumferential surface of the central hole 34.

[0035] Figure 3 illustrates the lightning suppression function of the lightning protection device 1 in one embodiment of the present invention.

[0036] Referring to Figure 3, 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 and the internal electrode 2 are grounded, positive charges also accumulate on the grounding conductor 4 and the 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.

[0037] [Effects of the embodiment]

[0038] In the above-described embodiment, the internal electrode 2 and the flat plate portions 31 and 32 of the external electrode 3 each have a circular shape centered on the central axis AX when viewed from above. This allows for the accumulation of a nearly uniform amount of charge in all directions when viewed from the central axis AX on each of the flat plate portions 31 and 32 of the external electrode 3. As a result, a lightning suppression type lightning arrester with excellent isotropic lightning protection performance is obtained. Furthermore, since both the internal electrode 2 and the flat plate portions 31 and 32 of the external electrode 3 are flat, it is easy to maintain a uniform distance over the entire area between the internal electrode 2 and the flat plate portion 31 of the external electrode 3, and it is easy to maintain a uniform distance over the entire area between the internal electrode 2 and the flat plate portion 32 of the external electrode 3. As a result, it is less likely that there will be areas where the distance between the internal electrode 2 and the flat plate portions 31 and 32 of the external electrode 3 is locally close. As a result, the distribution of negative charge on the external electrode 3 becomes uniform, and a decrease in lightning protection performance can be suppressed. Furthermore, it is not necessary to install lightning protection devices around the entire perimeter of the building's rooftop in a long-length configuration, making installation of lightning protection devices easy. In addition, since neither the internal electrode 2 nor the external electrode 3 are spherical, even when increasing the dielectric strength of the lightning protection device, it is not necessary to uniformly distance the external electrode 3 from the internal electrode 2 throughout the entire structure, and there is no need to enlarge the entire external electrode 3. Therefore, the dielectric strength can be easily adjusted.

[0039] Furthermore, the minimum distance between the internal electrode 2 and the external electrode 3 is determined by the distance d between the protruding portion 22 of the internal electrode 2 and the flat plate portion 31 or 32 of the external electrode 3. This allows the minimum distance between the internal electrode 2 and the external electrode 3 to be defined by the shape of the protruding portion 22, making it easier to adjust the lightning suppression performance of the lightning suppression type surge arrester.

[0040] Furthermore, the protruding portion 22 of the internal electrode 2 is spherical, and the external electrode 3 includes an arc-shaped portion 33. This prevents the formation of sharp edges on the outer diameter sides of both the internal electrode 2 and the external electrode 3, thereby suppressing localized concentration of negative charge on the outer diameter side of the external electrode 3.

[0041] Furthermore, the grounding conductor 4 includes support columns 41 and 42 that extend along the central axis AX, penetrate the central hole 34 of the external electrode 3, and reach the internal electrode 2. This allows the internal electrode 2 to be stably supported along the central axis AX.

[0042] Furthermore, by providing the insulating portion 5, the external electrodes 3 can be fixed to the support columns 41 and 42 while electrically insulating the support columns 41 and 42 from the external electrodes 3 at the insulating portion 5.

[0043] [Differentiation]

[0044] Next, a modified example of the above-described embodiment will be explained.

[0045] Figure 4 is a cross-sectional view showing a modified configuration of the lightning arrester 1 in one embodiment of the present invention.

[0046] Referring to Figure 4, the lightning arrester 1 in this modified example includes a convex member 6 in addition to the configuration of the lightning arrester in the above-described embodiment. The convex member 6 is provided on the upper surface 311 of the flat plate portion 31. The convex member 6 has a convex shape that protrudes upward when viewed in a cross-section including the central axis AX. The convex member 6 covers the flat plate portion 31. Preferably, the convex member 6 further covers the area from the inner diameter side end to the upper end 3321 of the outer peripheral surface 332 of the arc-shaped portion 32 of the external electrode 3. The convex member 6 may be a conductor or an insulator.

[0047] According to this modified example, since the flat plate portion 31 is covered by the convex member 6, foreign objects (such as bird droppings) falling onto the lightning arrester 1 from above can be easily directed along the surface of the convex member 6 to fall below the lightning arrester 1. This prevents foreign objects from adhering to the external electrode 3 and prevents a decrease in lightning suppression performance.

[0048] The configuration of the lightning arrester 1 in this modified example, other than that described above, is the same as that of the lightning arrester in the embodiment described above; therefore, the same reference numerals are used for the same components, and their descriptions are not repeated.

[0049] [others]

[0050] 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.

[0051] 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]

[0052] 1. Lightning protection device (an example of a lightning suppression type lightning protection device) 2. Internal electrodes (an example of internal electrodes) 3. External electrodes (an example of an external electrode) 4. Grounding conductor (an example of a grounding conductor) 5, 51, 52 Insulating parts (Examples of insulating parts, first insulating parts, and second insulating parts) 6. Convex member (an example of a convex member) 21. Flat plate portion of the internal electrode (an example of an internal flat plate electrode) 22. Protruding part of the internal electrode (an example of a protruding part) 31,32 Flat plate portion of external electrode (example of upper and lower flat plate electrode) 33. Arc-shaped portion of external electrode (an example of an arc-shaped portion) 34. Central hole of an external electrode (an example of a central hole) 35 Ventilation holes for external electrodes 41,42 Grounding conductor support (an example of a support) 211 Upper surface of the flat plate portion of the internal electrode 212 Lower surface of the flat plate portion of the internal electrode 221 Outer peripheral surface of the protruding part of the internal electrode 311,321 Upper surface of the flat plate portion of the external electrode 312,322 Lower surface of the flat plate portion of the external electrode 331 Inner circumferential surface of the arc-shaped portion of the external electrode 332 Outer peripheral surface of the arc-shaped portion of the external electrode 511, 521 Upper surface of the insulating part 522 Outer surface of the insulating part 3321 Upper end of the arc-shaped portion of the external electrode 3322 Lower end of the arc-shaped portion of the external electrode AX Central axis (an example of a central axis) CL cloud GR surface IS external electrode interior (an example of the internal structure of an external electrode) d Distance between the protruding portion 22 and the flat portion 31 or 32

Claims

1. The internal electrode is grounded, The system comprises an external electrode that is electrically insulated from the internal electrode and includes an interior that houses the internal electrode, The internal electrode includes a flat plate-shaped internal plate electrode that has a circular shape around its central axis when viewed from above. The aforementioned external electrode is A flat upper plate electrode, facing the upper surface of the inner plate electrode and having a circular shape centered on the central axis when viewed from above, A lightning suppression type lightning protection device, comprising a lower flat plate electrode that faces the lower surface of the internal flat plate electrode and has a circular shape around the central axis when viewed from above.

2. The internal electrode further includes a protrusion provided at the outer diameter side end of the internal flat plate electrode, The aforementioned protrusion is an electrode that protrudes from the internal flat plate electrode in at least one of the directions upward and downward. The lightning suppression type lightning protection device according to claim 1, wherein the minimum distance between the internal electrode and the external electrode is determined by the distance between the protruding portion and the upper plate electrode or the lower plate electrode.

3. The aforementioned protrusion is spherical, The external electrode further includes an arc-shaped portion provided on the outer diameter side of the protruding portion, The lightning suppression type lightning protection device according to claim 2, wherein the arc-shaped portion connects the upper flat plate electrode and the lower flat plate electrode, is arc-shaped when viewed in a cross-section including the central axis, and protrudes in the outer diameter direction with respect to the central axis.

4. The external electrode further includes a central hole provided in the lower flat plate electrode at a position including the central axis, The central hole connects the inside of the external electrode to the outside of the external electrode. It is a grounded conductor and further comprises a grounding conductor that is electrically connected to the internal electrode, The grounding conductor includes a support column extending along the central axis, The lightning suppression type lightning protection device according to claim 1, wherein the support column penetrates the central hole and reaches the internal electrode.

5. The support column further comprises an insulating part that insulates it from the external electrode, The insulating portion is A first insulating portion that includes an upper surface that contacts the lower surface of the lower plate electrode and covers the outer circumferential surface of the support column, It includes a second insulating portion provided inside the central hole and inside the external electrode, and covering the outer surface of the support column, The lightning suppression type lightning protection device according to claim 4, wherein the horizontal width of the second insulating portion is greater than the horizontal width of the first insulating portion.

6. The lightning suppression type lightning protection device according to claim 1, further comprising a convex member that covers the upper flat plate electrode and has a convex shape that protrudes upward when viewed in a cross-section including the central axis.

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