JP2009093936A - Lightning arrester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightning arrester including a lightning rod member with a rod and a lightning arrester electrode member with an electrode, capable of minimizing thunderbolt-induced damage to a protected object by disposing the lightning arrester electrode member in a position higher than the lightning rod member to make it hard to flow feedback current large enough to induce a thunderbolt thereby to suppress ground potential rising induced by the thunderbolt. <P>SOLUTION: The lightning arrester for protecting objects to be protected such as buildings and facilities from thunder bolts includes the lightning rod member 1 with the rod 1a and the lightning arrester electrode member 2 with the electrode 2a. The lightning arrester electrode member 2 is disposed in the position higher than the lightning rod member 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lightning arrester for protecting a protected object such as a building or equipment from lightning damage, and more particularly to a lightning arrester for avoiding a lightning strike around the protected object.

  When thunderclouds generated in the atmosphere develop, a leading discharge is generated from the thundercloud clouds toward the ground. When the preceding discharge progresses, the streamer having the charge opposite to the charge of the preceding discharge rises from the ground surface side. When the preceding discharge and the streamer are combined, a discharge path is formed between the ground and the thundercloud, and a large current flows between the thundercloud and the ground through the discharge path, and a lightning strike occurs.

  Conventional lightning arresters receive lightning strikes with a sharp-pointed needle placed at a higher position than the object to be protected, such as equipment including buildings, and are protected by absorbing a large current to the ground. It is configured to prevent lightning strikes on the body.

  As an example, Patent Document 1 discloses a lightning arrester that receives a lightning strike with a stylus arranged at a higher position than the object to be protected to protect the object to be protected.

JP-A-10-261495

  A conventional lightning arrester that receives lightning strikes with a stylus placed at a higher position than the object to be protected and absorbs lightning strikes caused by discharge breakdown between the thundercloud and the ground, can avoid direct lightning strikes on the object to be protected. However, it is extremely difficult to eliminate the lightning strike itself.

  By the way, the Japanese Industrial Standard (JIS standard) mentions the protection angle method and the newly-invented rotating sphere method in recent years as a design method for installing a lightning striker.

  However, even a lightning arrester member having a projecting needle designed by the design method of the protection angle method has a problem that the protection of the protected object is not always sufficient. For this reason, the rotating sphere method was newly introduced, but when recalculated with the rotating sphere method, which is a new design method, the lightning rod member is further positioned at a high position compared to the case of calculating with the protection angle method. Therefore, there is a problem that the installation cost of the lightning arrester increases and the construction cost of the lightning arrester increases.

  Furthermore, when the lightning arrester member receives a lightning strike and absorbs the current to the ground, the rise in the ground potential becomes a high potential, and this high potential on the ground has the potential to adversely affect the protected object. Therefore, it is necessary to make the grounding resistance of the ground low, and there is a problem that the construction cost of the lightning arrester is further increased.

  Furthermore, there has been a problem that lightning strikes at corners formed by the side walls and roof (rooftop) of the building as the object to be protected and at acute corners formed in the building.

  The object of the present invention is to suppress the occurrence of lightning when the developed thundercloud approaches the object to be protected, and to suppress the rise of earth potential, that is, the generation of high voltage on the earth, to the object to be protected by lightning. In addition to minimizing the effects of lightning, it is intended to avoid lightning strikes on corners and sharp corners of buildings as protected objects.

  In order to achieve the above-described object, the present invention provides a lightning arrester that protects a protected body such as a building or equipment or equipment from lightning or the like, and has a lightning arresting needle member having a projecting needle and an electrode body. A lightning pole member, and the lightning pole member is installed at a position higher than the lightning pole member, and secondly, a lightning arrester having a ground pole and an electrode body of the lightning pole member having the needle. The grounding electrode of the pole member is grounded to the same potential, and thirdly, the grounding electrode of the lightning arrester member having the projecting needle and the grounding electrode of the lightning arresting member having the electrode body are commonly grounded. There is a fourth example in which a lightning pole member having an electrode body is installed in the vicinity of a corner portion of an object to be protected such as a building.

  Since this invention has the structure mentioned above, there can exist the effect described below.

  The lightning arrester is composed of a lightning arrester member having a needle and a lightning pole member having an electrode body, and the lightning pole member is installed at a position higher than the lightning pole member, so when the thundercloud approaches the protected object, From the thundercloud, a preceding discharge is generated toward the lightning striker member, and a streamer is about to occur from the lightning striker member toward the thundercloud, but the electrode body of the lightning pole member suppresses the generation of the streamer. It is difficult for the preceding discharge from the thundercloud and the charge of the lightning rod member to be combined, and as a result, it becomes difficult for a large current return current such as a lightning strike to flow, and it is possible to suppress an increase in the potential of the ground caused by a lightning strike. It is possible to minimize damage to the object to be protected.

  As described above, it is very difficult to generate a feedback current, but a case where a feedback current is generated will be described. When it comes to the generation of the feedback current, the feedback current is absorbed by the ground electrode installed on the ground through the lightning rod member having the tip, but at this point, due to the action of the electrode body of the lightning rod member, Since the energy of thunderclouds is reduced, the return current of lightning strikes is reduced, so that an increase in ground potential can be suppressed and damage to the protected object can be minimized.

  Since the grounding pole of the lightning rod member having the projecting needle and the grounding electrode of the lightning rod member having the electrode body are grounded to the same potential, there is no difference voltage between the lightning rod member and the lightning pole member, and the lightning rod member. And the lightning pole member integrally act on the thundercloud, and therefore, it is possible to effectively avoid a lightning strike, and to prevent the occurrence of a voltage difference between the ground electrodes due to the lightning strike.

  Since the grounding pole of the lightning arrester member having the projecting needle and the grounding electrode of the lightning arresting electrode member having the electrode body are commonly grounded, for example, if the grounding electrode of the lightning arrester member having the existing projecting needle is utilized, the electrode body is provided. It is possible to omit the installation of the grounding pole of the lightning pole member, so that the installation cost of the grounding pole can be kept low, and the lightning rod member and the lightning pole member are grounded to the same potential. Therefore, the voltage difference between the grounding poles is suppressed, and the lightning rod member and the lightning pole member integrally act on the thundercloud, so that it is possible to effectively avoid the lightning strike, and both grounding poles accompanying the lightning strike. It is possible to prevent the occurrence of a differential voltage between them.

  Since the lightning protection pole member having the lightning protection wide surface portion is installed in the vicinity of the corner portion of the protected body such as a building, it is possible to avoid lightning strike to the corner portion of the protected body.

  Examples of the present invention will be described below. However, the present invention is not limited to the examples as long as the gist of the present invention is not exceeded.

  First, the lightning arrester of the present invention will be described with reference to FIGS. 1 and 2.

  Reference numeral 1 denotes a lightning arrester member having a projecting needle 1a, and the lightning arrester member 1 is attached to the tip of a support portion 1b made of a suitable conductive material. The lightning arrester member 1 is attached to a high position of the protected body A that needs to be protected from lightning strikes such as a high-rise building, and is configured to receive a lightning strike by the lightning striker member 1.

  E1 is a grounding electrode installed on the ground L. One end of the conductor W1 such as a cable is connected to the lightning arrester member 1, and the other end of the conductor W1 is connected to the grounding electrode E1 installed on the ground L. By connecting to, the lightning rod member 1 is connected to the ground L.

  2 is a lightning pole member installed at a position higher than the lightning rod member 1, and the lightning pole member 2 has a metal electrode body 2a and a support portion 2b made of a conductive material, and the electrode body 2a. Is formed in a substantially hemispherical shape with a hollow inside. The support portion 2b is provided vertically at the center of the inner surface of the electrode body 2a, and the lightning protection pole member 2 is attached to a high position of the protected body A such as a high-rise building, similarly to the lightning arrester member 1.

  E2 is a grounding electrode installed on the ground L. One end of the conductor W2 such as a cable is connected to the lightning protection member 2, and the other end of the conductor W2 is connected to the grounding electrode E2 installed on the ground L. The lightning pole member 2 is connected to the ground L by connecting to the ground L.

  Next, the operation of the lightning pole member 2 installed at a position higher than the lightning rod member 1 will be described.

  When a thundercloud matured in the atmosphere approaches the lightning protection pole member 2 installed on the protected body A, the charge on the ground surface L of the ground L having a charge opposite to that of the thundercloud is induced by the charge of the thundercloud. It will be distributed to the electrode body 2a which has the wide discharge surface of the lightning pole member 2 via W2. When the charge of the lightning pole member 2 is at a certain level, no discharge occurs. However, when it reaches a predetermined level, a preceding discharge occurs from the thundercloud toward the electrode body 2a of the lightning pole member 2. Accordingly, a streamer is generated from the electrode body 2a of the lightning pole member 2 toward the thundercloud, but the amount of charge rising from the ground surface of the ground L through the conductor W2 due to the impedance of the conductor W2. Since the surface of the electrode body 2a of the lightning pole member 2 facing the thundercloud is formed as a discharge surface portion having a large area, a large amount of electric charge is weakly momentum from many discharge points at once. Will be discharged. Therefore, the extension distance of the preceding discharge from the electrode body 2a of the lightning pole member 2 toward the thundercloud is short, and it is difficult to reach the thundercloud. Therefore, the preceding discharge does not combine with the thundercloud charge, and the occurrence of a lightning strike can be suppressed.

  FIG. 3 shows an embodiment different from the embodiment shown in FIG. 1. In this embodiment, the above-mentioned ground electrode E1 and ground electrode E2 are connected by a ground conductor W3. However, a configuration is shown in which the grounding electrode E1 of the lightning arrester needle member 1 and the grounding electrode E2 of the lightning protection pole member 2 have the same potential.

  FIG. 4 shows still another embodiment different from the embodiment shown in FIG. In this embodiment, one end is connected to the lightning rod member 1, the other end is connected to a building (protected body A) such as a building, and the other end is connected to the protected body A. The other end is provided with a conductor W5 connected to the structure grounding electrode E3 installed on the ground L, one end is connected to the lightning pole member 2, and the other end is connected to a building or the like. Conductor W6 connected to the building (protected body A) and one end connected to the protected body A, and the other end connected to the structure grounding electrode E3 installed on the ground L W7 is disposed.

  In the present invention, the lightning pole member 2 is installed such that the electrode body 2 a of the lightning pole member 2 is higher than the position of the needle 1 a of the lightning pole member 1. Further, as shown in FIG. 5, the projecting needle 1 a of the lightning arrester needle member 1 includes a predetermined tangent line T <b> 1 in contact with the upper surface of the electrode body 2 a constituting the lightning arrester member 2 and the center of the support portion 2 b of the lightning arrester member 2. It is installed so that the angle formed with the vertical line C1 falls within a range of approximately 60 degrees (60 °). Furthermore, the lightning pole member 2 is installed in a range where the distance D1 between the center vertical line C1 of the support portion 2b of the lightning pole member 2 and the center vertical line C2 of the support portion 1b of the lightning striker needle portion 1 is approximately 10 m. Is preferred.

  Moreover, it is preferable that the radius of the electrode body 2a in which the inside of the lightning pole member 2 is formed in a substantially hemispherical shape having a hollow is approximately 50 mm or more. The larger the radius of the electrode body 2a of the lightning pole member 2, the more discharge paths are formed with respect to the thundercloud, but the radius of the electrode body 2a of the lightning pole member 2 is about 50 mm or less. If the charge of the lightning pole member 2 hardly acts on the thundercloud, and if the radius of the electrode body 2a of the lightning pole member 2 is about 50 mm or more, the manufacturing cost and installation cost of the lightning pole member 2 increase. It will be.

  As shown in FIG. 6, the lightning pole member 2 is preferably installed in the vicinity of the corner portion A1 between the side wall a1 of the building A and the roof (rooftop) a2. If the lightning pole member 2 is installed at a position away from the corner portion A1 of the building A, the electric field concentrates on the corner portion A1 of the building A, and lightning strikes easily occur. By installing in the vicinity of the corner portion A1 of the object A, lightning strikes to the corner portion A1 of the building A can be avoided. In addition, the number of lightning arrester needle members 1 and the number of lightning pole members 2 installed in the vicinity of the corner portion A1 of the building A are not in a one-to-one relationship and can be set as appropriate.

  Further, in the embodiment shown in FIG. 1, an example in which one lightning pole member 2 is installed with respect to one lightning rod member 1 is shown. A plurality of lightning pole members 2 can be installed on the member 1.

  In FIG. 7, W8 is a lightning arrester conductor that connects the lightning arrester member 1 and the lightning arrester pole member 2 in the vicinity thereof. The lightning arrester member 1 and the lightning arrester pole member 2 are connected by the lightning arrester conductor W8. By connecting, as described above, it is not necessary to connect the grounding pole E1 of the lightning rod member 1 installed on the ground L and the grounding pole E2 of the lightning pole member 2 within the ground L. Construction cost can be reduced. Further, by utilizing the existing grounding electrode E4 connected via the conductor W9 of the existing lightning arrester needle member 1, it is possible to further reduce the construction cost of the lightning arrester without newly constructing the grounding electrode. can do.

  In FIG. 8, the support member S is composed of a vertical part s1 and a branch part s2 branched from the vertical part s1, and the lightning pole member 2 is attached to the vertical part s1, and the lightning arrester needle is attached to the branch part s2. The example which attached the member 1 is shown. Also in this case, as described above, the lightning rod member 1 is attached at a position lower than the lightning pole member 2. As described above, the lightning arrester member 1 and the lightning pole member 2 can be connected to the same potential only by installing the support member S having the vertical part s1 and the branch part s2, and the construction of the lightning arrester can be performed. It can be simplified, and further labor saving and cost reduction of construction work can be realized.

  The results of performing a high-pressure discharge test (a high-pressure discharge test using a parallel plate in conformity with French NFC17-102) will be described below.

  First, when only the lightning arrester needle member 1 having the projecting needle 1a is installed between the parallel plates and voltage application of a maximum of 700 KV is repeated between the parallel plates, it is natural that the lightning arrester has a probability of almost 100%. Discharge to the needle 1a of the needle member 1 was confirmed.

  Secondly, when only the lightning pole member 2 having the electrode body 2a is installed between the parallel plates, and voltage application of a maximum of 700 KV is repeated between the parallel plates, the discharge to the electrode body 2a has a probability of 95% or more. It was confirmed not to.

  Thirdly, the lightning arrester member 1 having the projecting needle 1a and the lightning arrester electrode member 2 having the electrode body 2a are spaced at a distance of about 0.5 m, and the height of both is the same, and the lightning arrester having the projecting needle 1a. When the tip member 1 and the lightning pole member 2 having the electrode body 2a are installed between the parallel plates and voltage application of a maximum of 700 KV is repeated between the parallel plates, the discharge of the lightning tip member 1 to the tip 1a is confirmed. However, no discharge of the lightning pole member 2 to the electrode body 2a was confirmed.

  Fourth, the lightning arrester member 1 having the projecting needle 1a and the lightning arrester electrode member 2 having the electrode body 2a are spaced apart by about 0.5 m, and the height of the projecting needle 1a of the lightning arrester projecting member 1 is set to the lightning arrester pole. The height of the electrode body 2a of the member 2 is lowered by a predetermined amount, and the stylus 1a of the lightning arrester piercing member 1 enters the range of the protection angle of the electrode body 2a of the lightning proof pole member 2 so as to be 60 degrees. When a lightning pole member 1 having an electrode and a lightning pole member 2 having an electrode body 2a are installed between parallel flat plates and voltage application of a maximum of 700 KV is repeated between the parallel plates, the electrode body 2a of the lightning pole member 2 is applied. No discharge was confirmed, and no discharge of the lightning arrester member 1 to the projecting needle 1a was confirmed.

  This proves that the lightning pole member 2 having the electrode body 2a acts on the thundercloud and can avoid the lightning strike to the needle 1a of the lightning striker member 1, and therefore lightning can be significantly reduced. The increase in ground potential can be largely avoided, and therefore the damage to the protected object A can be greatly reduced.

FIG. 1 is a front view of a lightning arrester according to the present invention. FIG. 2 is an enlarged front view of a lightning protection electrode member constituting the lightning protection device of the present invention. FIG. 3 is a front view of a lightning arrester according to another embodiment of the present invention. FIG. 4 is a front view of a lightning arrester according to still another embodiment of the present invention. FIG. 5 is a front view showing a positional relationship between a lightning arrester member and a lightning pole member constituting the lightning arrester of the present invention. FIG. 6 is a schematic perspective view of a lightning arrester according to still another embodiment of the present invention. FIG. 7 is a front view of a lightning arrester according to still another embodiment of the present invention. FIG. 8 is an enlarged front view of a support member for attaching a lightning arrester member and a lightning pole member constituting the lightning arrester of the present invention to a protected body.

Explanation of symbols

A ... Protected object E1-E4 ... Grounding electrode L ... Earth W1-W9 ... Conductor 1 ·············· Lightning striker member 1a ······································ ... Electrode body

Claims (4)

  A lightning arrester characterized by comprising a lightning arrester needle member having a projecting needle and a lightning arrester electrode member having an electrode body, wherein the lightning arrester electrode member is installed at a position higher than the lightning arrester needle member.   2. The lightning arrester according to claim 1, wherein the grounding pole of the lightning arresting needle member having the projecting needle and the grounding electrode of the lightning arresting electrode member having the electrode body are grounded to the same potential.   The lightning arrester according to claim 1 or 2, wherein the grounding pole of the lightning arrester needle member having the projecting needle and the grounding electrode of the lightning arresting electrode member having the electrode body are shared ground.   The lightning arrester according to any one of claims 1 to 3, wherein a lightning pole member having an electrode body is installed in the vicinity of a corner portion of a protected body such as a building.

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