JP2011028920A - Lightning rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To flow a lightning current in the ground through a specific path in a lighting strike, and to provide effect of preventing generation of an electromagnetic field by induced lightning in a building. <P>SOLUTION: The lightning rod 1 is laid on a roof 3 of the building 2 with insulation from the building 2. A lightning protection cable 5, which is formed of a single or a plurality of power cables with shield or high-frequency coaxial cables for power, connects the lightning rod 1 and a grounding electrode 4. The lightning protection cable 5 is passed in a metal conduit 6 previously routed through an inside of the building 2, and is drawn from a top to a bottom of the building 2. When lightning is induced to the lightning rod 1, an induced current in an opposite direction to the lightning current flowing in the lighting protection cable 5 flows through the metal conduit 6 so as to suppress generation of an external magnetic field of the lightning protection cable 5 by a stroke current. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a lightning rod on a building such as a high-rise building or an independent building-up conductor, or a lightning rod for a side of a building or a conductor for a side of a building (hereinafter collectively referred to as “lightning rod”), by induced lightning generated in the building. It relates to lightning rods that have the effect of suppressing damage.

  Conventionally, as shown in FIG. 9, as a method of protecting a building against a lightning strike in a building, as shown in JIS-A-4201, a lightning rod is set up, and lightning is not directly applied to the building by guiding the lightning to the lightning rod. I am doing so. This is intended to prevent building damage and fire.

  However, in recent years, in addition to the increase in lightning strike probability due to the rise of high-rise buildings, the added value of electronic information by electronic devices used in the building continues to rise. Information and electronic circuits frequently cause functional paralysis and damage due to induced electromotive force caused by lightning strike current.

The lightning current is an impulse and is considered to have wave components of various frequencies up to about DC to 10 MHz. In FIG. 9, when a lightning current flows through the lightning rod 1, the current flows through the reinforcing bars of the building 2 because the insulation is not particularly provided. When these currents flow through the metal reinforcement (rebar) in Building 2, low-frequency component waves flow through the outer wall of the building due to the skin effect, forming a magnetic shield, and a magnetic field is formed inside the building. Therefore, it is thought that the thunder phenomenon is hindered. However, when a high frequency is reached, a metal resonance path in the building 2 flows, for example, a λ / 2 wavelength series resonance system path is formed, and the path becomes a low-impedance system of waves of a specific frequency. A case where the current is divided into the building 2 is considered. Thereby, an induced magnetic field is generated inside the building 2, an induced electromotive force is generated in an electronic device or the like interlinked with the magnetic field generated inside the building 2, and a failure occurs in the electronic device or the like.
As described above, the conventional lightning protection system is a countermeasure for a strong electric system and has not considered a countermeasure for a weak electric device of an electronic engineering system.

  As a countermeasure, there is a method for protecting an electronic device using an element called SPD. Although this method is effective, it is a local measure, and basically an SPD is attached to each electronic device or electric circuit, and the number thereof is enormous. Further, it is assumed that this SPD element does not function effectively when an excessive voltage is applied to an electronic device in a building due to a strong electromagnetic impulse during a lightning strike.

  As described above, what uses an SPD element is a local countermeasure, and advanced research requires not only such a local countermeasure but also an improvement in lightning resistance of the entire building. As a countermeasure, there is an independent lightning arrester. This system strengthens the electrical insulation of the lightning rod and the cable (down conductor) attached to it, and shields the down conductor to allow lightning current to flow through the building structure during lightning strikes and The potential rises, and the lightning current is prevented from entering from the ground.

JP-A-11-40390

  However, even if this independent lightning arrester is used, simply shielding the down conductor does not prevent electrostatic induction, but it does not prevent electromagnetic induction. Excessive voltage applied to electronic equipment due to the powerful electromagnetic impulse. Addition cannot be completely suppressed. Moreover, it is necessary to design the electrical insulation performance of a lightning rod and a cable high, and a problem remains in an effect and a design surface.

  The present invention considers such a conventional technique, and provides a lightning rod having an effect of causing a lightning current to flow into the ground through a specific path during a lightning strike and not generating an electromagnetic field due to the induced lightning in a building. It is intended.

  Therefore, in the present invention, the lightning rod is insulated with a station post insulator or the like and laid on the roof of a high-rise building, and the design of the protection angle is based on a conventional method such as JIS-A-4201. Use a shielded power cable or a high-frequency coaxial cable for power between the lightning rod and the grounding electrode, and store it in a metal conduit that is not easily corroded, such as zinc drawing, so that the induced current of lightning can flow. Or it shall be provided outside and pulled down from the upper part of the building. The metal pipe line is not limited to a pipe line, and may be a duct-like thing, a net-like thing, a thing wound with a copper tape or the like, as long as it is an electromagnetic shield cylinder.

  Specifically, the invention according to claim 1 insulates the lightning rod on the building or the independent building up conductor, or the building side lightning arrester or the building side lightning building up conductor from the building, and the roof or side surface of the building. Between the lightning rod or the independent erection conductor and the grounding pole, connect with one or more shielded power cables or power high-frequency coaxial cables, and in the electromagnetic shield cylinder passed through the building in advance or outside By pulling down from the upper part of the building through the cable and when lightning is induced to the lightning rod or the independent building raising conductor, an induced current opposite to the lightning current flowing in the cable flows into the electromagnetic shield cylinder, thereby causing a lightning current. The lightning rod is configured to cancel the magnetic field generated outside the cable.

  According to a second aspect of the present invention, in the first aspect of the invention, a ground electrode is connected to an inner conductor of the one or more shielded power cables or power high-frequency coaxial cables, and the cable shield or power high-frequency coaxial is connected. A grounding electrode is connected to the outer conductor of the cable, the grounding resistance value of the grounding electrode connected to the inner conductor of the shielded power cable or power high-frequency coaxial cable, and the outer conductor of the shielded power cable or power high-frequency coaxial cable The lightning rod is provided with a grounding electrode in which the grounding resistance is adjusted so that the sum of the grounding resistance values of the grounding electrodes connected to the cable matches the characteristic impedance of the cable.

  The invention of claim 3 is the invention of claim 1 or 2, wherein a ground electrode is connected to an inner conductor of the one or more shielded power cables or high-frequency coaxial cables for power, and the shield or coaxial cable of the cables In the case of a single grounding electrode connected to the inner conductor, a grounding electrode is connected to the outer conductor, and the grounding electrode is connected using an inductance. A lightning rod with a lower resistance value was used.

  Further, the invention of claim 4 is the invention according to any one of claims 1 to 3, wherein the electromagnetic shield cylindrical body is electrically connected between the entrances and exits with a mesh-like electric wire covering the outer periphery of the building, When a lightning strike current flows through the cable, a lightning rod that recirculates the induced current flowing in the opposite direction to the lightning strike current to the mesh-shaped electric wire in the outdoor part of the building is used.

  Further, the invention of claim 5 is the invention according to any one of claims 1 to 3, wherein the electromagnetic shield cylindrical body is electrically connected between the entrance and exit with one or more electric wires passing through the outer periphery of the building, When a lightning strike current flows through the cable, a lightning rod that recirculates an induced current flowing in a direction opposite to the lightning strike current to the electric wire in the outdoor part of the building is used.

  Further, the invention of claim 6 insulates the lightning rod on the building or the independent building up conductor, or the building side lightning arrester or the building side lightning building up conductor from the building, and lays it on the roof or side of the building. From the lightning rod or the independent uplifting conductor to the grounding pole, connect with one or more shielded power cables or high-frequency coaxial cables for power, and lower the cable from the top to the bottom of the building, and shield the cable near the lightning rod Alternatively, the outer conductor of the coaxial cable and the shield of the cable in the vicinity of the ground electrode or the outer conductor of the coaxial cable are electrically connected with a mesh-shaped electric wire covering the outer periphery of the building, and the lightning rod or the independent ridge-up conductor When lightning is induced, an induced current that flows in the opposite direction to the lightning strike current that flows through the inner conductor of the cable or coaxial cable is the shield. Flows to the outer conductor of the coaxial cable, and a lightning rod to further refluxed for current building outside the mesh wire.

  Further, the invention of claim 7 is characterized in that the lightning rod on the building or the independent building up conductor, or the building side lightning arrester or the building side lightning building up conductor is insulated from the building and laid on the roof or side of the building. From the lightning rod or the independent uplifting conductor to the grounding pole, connect with one or more shielded power cables or high-frequency coaxial cables for power, and lower the cable from the top to the bottom of the building, and shield the cable near the lightning rod Alternatively, the outer conductor of the coaxial cable and the shield of the cable near the ground pole or the outer conductor of the coaxial cable are electrically connected with one or a plurality of electric wires passing through the outer periphery of the building, and the lightning rod or the independent building up conductor When lightning is induced, an induced current that flows in the opposite direction to the lightning strike current that flows through the inner conductor of the cable or coaxial cable is the shield. Flows to the outer conductor of the coaxial cable, and a lightning rod to further refluxed for current building outside of the wire.

  According to the first aspect of the present invention, when lightning is induced to the lightning rod or the independent ridge conductor, an induced current in a direction opposite to the lightning current flowing in the shielded power cable or power high-frequency coaxial cable is the electromagnetic shield cylinder. To suppress the generation of external magnetic field of the cable due to lightning current, and to prevent the electronic devices in the building from being damaged by induced electromotive force, and to protect the building and the electronic devices in the building from lightning strike To do.

  Further, according to the invention of claim 2, in addition to the effect of the invention of claim 1, the high-frequency component of the lightning current has a ground resistance of the ground electrode connected to the inner conductor of the shielded power cable or power high-frequency coaxial cable. A grounding pole in which the grounding resistance is adjusted so that the sum of the value and the grounding resistance value of the grounding pole connected to the outer conductor of the shielded power cable or power high-frequency coaxial cable matches the characteristic impedance of the cable; Therefore, the reflected wave is attenuated, and the energy is absorbed by the ground, and the voltage rise of the lightning rod due to the reflected wave is suppressed. As described above, since the invention of claim 2 is provided with countermeasures for the high-frequency component and the low-frequency component of the lightning current, the magnetic field caused by the lightning induced electromotive force is not completely generated in the building. It protects electronic equipment inside the building from lightning strikes.

  According to the invention of claim 3, in addition to the effect of the invention of claim 1 or 2, a ground electrode is connected to an inner conductor of the one or more shielded power cables or high-frequency coaxial cables for power, and the cable By connecting a grounding pole to the outer conductor of the shield or coaxial cable and connecting between the grounding poles using an inductance, the resistance value of the grounding pole connected to the inner conductor can be determined independently from the inner conductor. The resistance value is lower than that in the case of the connected ground electrode, and the low-frequency component of the lightning current is shunted to the ground electrode 4a and the ground electrode 4b, becomes low resistance, and more easily flows to the ground.

  In addition, according to the inventions of claims 4 and 5, by laying a short-circuit wire made of a mesh-like electric wire or a non-mesh electric wire so as to wrap the building outside the building, the inside of the electric wire, that is, the induction of the interior of the building Since the magnetic field becomes almost zero or small, the lightning induced electromotive voltage in the building is reduced, and the occurrence of a failure due to the induced lightning in the building can be prevented. Moreover, according to the invention of Claim 6 and 7, there exists an effect similar to the invention of the said Claim 4 and 5.

  According to the present invention, the lightning rod on the building or the independent building up conductor, or the building side lightning arrester or the building side lightning raising conductor is insulated from the building and laid on the roof or side of the building, and the lightning rod or independent Between the built-up conductor and the grounding electrode, connect with one or more shielded power cables or power high-frequency coaxial cables (hereinafter referred to as lightning protection cables), and place them inside the electromagnetic shield cylinder that has been passed through the building in advance or outside. Pulled down from the upper part of the building through the cable, and when lightning is induced to the lightning rod or the independent building raising conductor, an induced current opposite to the lightning current flowing in the cable flows to the electromagnetic shield cylinder, thereby causing a lightning strike current. A lightning rod configured to suppress generation of an external magnetic field of the cable and suppress generation of an induced electromotive voltage in a building. It was.

The reason for such a configuration is as follows.
The lightning current is an impulse, and is considered to be a waveform obtained by collecting waves from the DC to 10 MHz bands having substantially the same amplitude. Therefore, first, measures are taken according to the frequency band.
Let the length of the lightning protection cable be l. Therefore, if the distribution constant is not used, the reflected wave becomes large and adverse effects such as an increase in electromotive voltage generated at the end of the lightning protection cable occur. Therefore, the cable travels at a speed c, and the wavelength is λ and the frequency is f (= 1 / λ).

In general, the frequency at which the distribution constant should be taken into consideration is λ = c / f = 10 l (1) because the frequency that is 10 times the cable length l (hereinafter, l represents small el) is one wavelength or more.
F = c / 10l (2 formulas)
That is, the frequency of lightning impulses up to c / 10l ≦ f ≦ 10 MHz must be handled as a distributed constant. Therefore, as described in the second aspect of the invention, the resistance value of the ground electrode connected to the shield or outer conductor of the lightning protection cable end (cable head) on the ground side against lightning current in this frequency range. the sum of the resistance value R of the ground electrode is connected to the r and the cable or the inner conductor (r + R) together with the characteristic impedance Z ₀ of the lightning cable (matching) is taken, to prevent reflection waves. If this matching is not performed, the reflected wave generated at the end of the lightning protection cable propagates through the shield or the outer conductor and propagates to the lightning rod side. At this time, since the incident wave and the reflected wave propagate out of phase, an induced electromotive voltage is generated outside the lightning protection cable due to a displacement current or the like, and radio waves are radiated, causing a failure in other electrical devices. The reflected wave is reflected to the lightning rod side, and the voltage of the lightning rod rises due to the interference of the wave. Therefore, in this case, it is necessary to use a cable end (cable head) having a withstand voltage higher than necessary. Thus, the alignment is important.

A lightning current in a frequency band in the range of f <c / 10l is handled in a lumped parameter system. In this case, the voltage E induced to the center conductor of the lightning protection cable is Faraday's law of electromagnetic induction, assuming that the inductance of the center conductor of the cable is L.
E = -L (di / dt) (3 formulas)
Thus, an induced electromotive voltage is generated in the direction opposite to the direction in which the lightning current flows. That is, assuming that the direction in which current flows from the lightning rod to the ground electrode is +, an electromotive voltage of − is generated from the ground electrode to the lightning rod, and a high voltage is induced at the tip of the lightning rod.
Here, since the lightning current flowing in the lightning arrester cable can be considered as a current path flowing in one direction, it is considered in a model in which a return current flows at infinity, and the inductance L in the above three formulas is:

Given in. Here, a is the radius of the cable conductor. μ ₀ is the vacuum permeability. If this voltage is induced in the cable as it is, the withstand voltage of the cable and the cable end must be high. In addition, an induced voltage generated by a magnetic field generated in the periphery increases, and various faults, so-called induction faults, occur. Therefore, as described in the first aspect of the present invention, the lightning protection cable is housed in an electromagnetic shield cylinder, for example, a metal conduit, and pulled down from the upper part to the lower part of the building. Since the mutual induction M for this metal pipe is approximately equal to the cable length l and the metal pipe length,

Eventually, the electromotive force E induced in the pipeline is E = −M (di / dt) (Equation 6)
It is. Here, b is the outer diameter of the metal pipeline.
If a <b, but if the cable length l is sufficiently long, Equation 6 is able to induce a mutual induction voltage in the metal pipe line that is approximately equal to that generated in the inductance L of the cable. In other words, this induced electromotive force can generate an induced current in the opposite direction to the lightning current flowing in the cable in the metal conduit.

  In addition, a short-circuit path with a small impedance is formed at both ends of the metal pipeline. That is, as described in the invention of claim 4, by laying a short-circuit wire with a mesh-shaped unshielded insulated wire so as to wrap the building outside the building, the induction magnetic field inside the mesh, that is, the inside of the building becomes almost zero. Therefore, the lightning induced electromotive voltage in the building is reduced, and the occurrence of a failure due to the induced lightning in the building can be prevented. If this is constructed as shown in the invention of claim 4 or 5, it is possible to more reliably prevent the occurrence of failure due to induced lightning in the building, but without doing so, the metal conduit is electrically connected to the building rebar. Even if they are brought into contact with each other, the lightning induced electromotive voltage in the building is reduced, and the same effect can be obtained. The grounding of the building bar arrangement is considered to be a factor that causes an extra current path to flow, and it is better not to do so from the viewpoint of relaxing the magnetic field in the building, but it may or may not be grounded.

  Furthermore, as described in the third aspect of the invention, the energy of the wave in the low frequency region that can be handled by the lumped constant is obtained from the ground electrode connected to the inner conductor side of the shielded power cable or the power high frequency cable and the shield or coaxial cable. By connecting the ground electrode connected to the outer conductor with an inductance, the resistance value can be made lower than the resistance value of the ground electrode alone connected to the inner conductor. Therefore, in this case, the lightning current easily flows through the ground electrode connected to the inner conductor.

  In addition, without using an electromagnetic shield cylinder such as the metal pipe, the mesh-shaped electric wire is used to wrap the building from the lightning rod side to the ground electrode at the outer conductor end of the shielded power cable or power high-frequency coaxial cable. As described above, an induced current caused by an induced electromotive force of a lightning current flows to the shield or outer conductor of the cable, and this has an effect of canceling an external magnetic field generated by the lightning current flowing to the inner conductor. It is done.

  Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a lightning rod according to the present invention, and the number of pull-down cables will be described as one.

The lightning rod 1 is insulated with a station post insulator and laid on the roof 3 of a building 2 such as a high-rise building. The design of protective angle shall be in accordance with JIS-A-4201. Between the lightning rod 1 and the grounding electrode 4, a lightning protection cable 5 comprising a shielded power cable or a power high-frequency coaxial cable is connected. On the other hand, a metal pipe 6 that is not easily corroded, such as zinc drawing, is provided from the roof 3 of the building 2 to the ground, and the lightning protection cable 5 is passed through the metal pipe 6 and pulled down into the ground. The conductor or shield layer of the lightning protection cable 5 and the metal conduit 6 are not in electrical contact. The metal pipe 6 is piped inside the building 2, but the place is not limited, and can be piped to a cable housing duct, an elevator shaft, and the like, and further along the outer wall of the building 2. May be provided. However, this metal conduit 6 is preferably electrically insulated from the surroundings.

The grounding electrode 4 is actually a grounding electrode 4a connected to the end of the inner conductor of the lightning protection cable 5 or the coaxial cable, and a grounding electrode connected to the end of the outer conductor of the shield or coaxial cable. 4b. Then, the respective ground resistance values are adjusted so that the sum of the resistance value RΩ of the ground electrode 4 a and the resistance value rΩ of the ground electrode 4 b matches the characteristic impedance Z ₀ of the lightning protection cable 5. That is, the characteristic impedance of the lightning protection cable 5 and the characteristic impedance of the ground are matched.

  Thereby, for the lightning current in the range where the frequency of the lightning impulse is c / 10l ≦ f ≦ 10 MHz, the resistance value r of the outer conductor grounding electrode 4b connected to the end of the lightning arrester cable 5 on the ground side and the inner conductor The effect of suppressing the voltage rise of the lightning rod 1 is obtained by absorbing with the sum r + R of the resistance value R of the ground electrode 4a and preventing reflection. For lightning current in a frequency band in the range of f <c / 10l, a mutual induced electromotive voltage that is substantially equal to that generated in the inductance L of the lightning arrester cable 5 is induced in the metal conduit 6, and this induced electromotive force is induced. As a result, an induced current is generated in the metal pipe 6. Thereby, the magnetic field generated outside can be offset by the lightning current flowing through the inner conductor and the induced current flowing through the metal pipe 6, and the magnetic field is not generated outside the metal pipe 6, that is, inside the building 2.

  As described above, in the lightning protection system according to the first embodiment, the lightning current caused by the lightning strike is divided into a high frequency and a low frequency, and a separate process is performed for the high frequency component and the low frequency component, respectively. I try not to make it happen.

  In addition to the first embodiment, as shown in FIG. 2, the grounding electrode 4a connected to the cable of the lightning arrester cable 5 or the inner conductor of the coaxial cable and the shield of the lightning arrester cable 5 or the outer conductor of the coaxial cable are connected. The ground electrode 4b is connected via an inductance L. As a result, the resistance value of the ground electrode 4a connected to the inner conductor or the like can be made lower than the resistance value of the ground electrode 4a connected to the inner conductor or the like alone, and the low frequency component of the lightning current is grounded. The current is diverted to the pole 4a and the ground electrode 4b, so that the resistance becomes low and it becomes easier to flow to the ground. In this case, the high-frequency components L, R, and r have a low-pass filter effect, flow between the ground electrode 4a and the ground electrode 4b, and attenuate the reflected wave at the cable end.

  In FIG. 3, L, R, and r have a low-pass filter effect on the high-frequency component of the lightning current, and flow between the inner conductor grounding electrode 4a and the outer conductor grounding electrode 4b. It shows that it attenuates.

  FIG. 4 shows the configuration of the second embodiment of the present invention, in which a mesh shield covering the outer periphery of the building 2 from the entrance of the metal conduit 6 near the lightning rod 1 to the exit of the metal conduit 6 near the ground electrode 4 is shown. This is electrically connected by the insulated wire 7 without other components, and the other configuration is the same as in the first embodiment. By wiring in this way, when a lightning current flows in the lightning protection cable 5, the induced current flowing in the opposite direction to the lightning current can be returned to the outdoor part of the building, and the path through which the current flows inside the building 2 can be suppressed. Since the induction magnetic field inside the building 2 can be made substantially zero or small, it is possible to prevent a failure caused by the induced lightning in the building 2.

  The mesh-shaped unshielded insulated wire 7 is not limited to this, and may be a mesh-free, unshielded insulated wire. FIG. 5 shows a plan view of the roof 3 of the building 2. In this way, the unshielded insulated wires 8 are provided radially from the metal conduit 6, pulled down along the outer wall of the building 2, and the lower surface of the building 2 is turned up. To the outlet of the metal pipe 6. The unshielded insulated wire 8 and the outer wall of the building 2 can be connected by, for example, welding to a metal gutter or the like. However, if an extra current path is created, it is induced in the building 2 It is desirable to isolate the bypass circuit from other components as much as possible because of the risk of voltage connection. The unshielded insulated wire 7 or 8 can basically be used even if it has a shield or is not an insulated wire.

  Further, when a short-circuit path formed by the mesh-shaped unshielded insulated wire 7 in the frequency band included in the lightning current has a distributed constant system cutoff impedance, that is, a short-circuit parallel resonance impedance, only that frequency is described earlier. Since the effect of the induced current flowing in the direction opposite to the lightning strike current can no longer be expected, the Q value can be adjusted by inserting a low-pass filter such as an LR parallel type into the short-circuit path formed by the mesh-like unshielded insulated wire 7. Is also possible.

  Further, FIG. 6 shows that the bar arrangement of the building 2 uses metal and nonmetal, the metal arrangement 9 such as a reinforcing bar is used for the roof, the outer wall and the base part, and all the metal arrangements inside the building 2 are nonmetal, for example, It is a schematic block diagram at the time of using aramid etc. In this case, since there is no shunting into the building 2 during a lightning strike, the metal roof 6 and the metal conduit 6 that houses the lightning protection cable 5 are electrically connected to the roof 3 and the foundation. In addition, when all the reinforcing bars inside the building 2 are made of non-metal, and any of the rooftop 3, the outer wall, and the foundation part is made non-metallic, the non-metallic reinforcing part covers the outside of the building 2 To bypass with a bypass cable.

  FIG. 7 is a schematic configuration diagram showing an example in which a plurality of lightning protection cables 5 are pulled down. In this case, since the magnetic field is canceled by the current flowing through the metal conduit 6 and the short-circuit line 10a or 10b due to the current flowing through the lightning protection cable 5, the short-circuit line 10a of one metal conduit 6 and the short-circuit wire 10b of the other metal conduit 6 Is preferably insulated. This is because when a lightning current flows through the lightning protection cable 5 accommodated in one metal conduit 6, an induced electromotive voltage is generated in the one metal conduit 6, and the short-circuit line 10 a connected to the metal conduit 6. When the short-circuit wire 10a and the short-circuit wire 10b are connected to each other, an induced electromotive voltage is also generated in the other metal conduit 6, and a magnetic field is generated inside the building 2 near the other metal conduit 6. May occur. The short-circuit wire 10a or 10b is the same as the mesh-shaped unshielded insulated wire 7 or unshielded insulated wire 8.

  FIG. 8 is a schematic configuration diagram of a lightning arrester system in which the lightning rod 1 provided on the roof 3 of the building 2 and the lightning rod 1 for building side lightning are provided on the side wall portion of the building 2. A T-branch 11 is provided in the lightning protection cable 5 in the metal conduit 6, and the lightning rod 1 provided on the roof 3 of the building 2 is connected to the lightning rod 1 provided on the side wall of the building 2. Other configurations are the same as those in the first and second embodiments.

  In FIG. 8, the lightning protection cable 5 is schematically shown to have a structure in which the lightning protection cables 5 are in contact with each other and the reflected wave of the lightning current does not reach the building until reaching the underground buried portion. It is.

It is a schematic block diagram of Example 1 of this invention. It is a principal part structure principle diagram added to Example 1 of this invention. It is a reflection suppression principle figure of the high frequency component of the lightning current in the structure added to Example 1 of this invention. It is a schematic block diagram of Example 2 of this invention. It is a laying conceptual diagram of the radial insulated wire laid on the building roof used for Example 2 of this invention. It is a schematic block diagram which shows the connection state of the metal pipe line in the case where the internal part of the building bar arrangement of Example 2 of this invention is comprised with a non-metal, and the bar arrangement | positioning of a rooftop, a side wall, and a base part. In Example 2 of this invention, it is a schematic block diagram at the time of providing a plurality of lightning protection cables. In Example 2 of this invention, it is a schematic structure perspective view which shows the state which pulled down the lightning rod on the building and the lightning rod on the side wall with one lightning arrester cable. It is a schematic block diagram of the conventional lightning protection system.

DESCRIPTION OF SYMBOLS 1 Lightning rod 2 Building 3 Rooftop 4 Ground pole 5 Lightning protection cable 6 Metal conduit 7 Net-shaped unshielded insulated wire
8 Unshielded insulated wire 9 Metal reinforcement 10 Short circuit 11 T branch

Claims (7)

  Insulate the lightning rod on the building or the independent building up conductor, or the building side lightning arrester or the building side lightning building up conductor from the building, lay it on the roof or side of the building, and ground it from the lightning rod or the independent building up conductor Between the poles, connect with one or more shielded power cables or high-frequency coaxial cables for power, and pull down from the top to the bottom of the building through the cable in the electromagnetic shield cylinder passed through the building inside or outside in advance. Therefore, when lightning is induced to the lightning rod or the independent ridge conductor, an induced current opposite to the lightning current flowing in the cable flows to the electromagnetic shield cylinder, and the magnetic field generated outside the cable due to the lightning current is canceled out. A lightning rod characterized by having a configuration to be made.   A grounding electrode is connected to an inner conductor of the one or a plurality of shielded power cables or power high-frequency coaxial cables, a grounding electrode is connected to an outer conductor of the shield of the cables or the power high-frequency coaxial cable, and the shielded power cable Or the value of the sum of the ground resistance value of the ground electrode connected to the inner conductor of the high frequency coaxial cable for power and the ground resistance value of the ground electrode connected to the outer conductor of the shielded power cable or the high frequency coaxial cable for power is The lightning rod according to claim 1, wherein a grounding pole having the grounding resistance adjusted to match the characteristic impedance of the cable is provided.   Connect a grounding electrode to the inner conductor of the one or more shielded power cables or power high-frequency coaxial cables, connect a grounding electrode to the shield of the cable or the outer conductor of the coaxial cable, and induct between the grounding electrodes. And a resistance value of a ground electrode connected to the inner conductor is set lower than a resistance value of a single ground electrode connected to the inner conductor. Or the lightning rod of 2.   By electrically connecting between the entrance and exit of the electromagnetic shield cylinder with a mesh-shaped wire covering the outer periphery of the building, when a lightning current flows through the cable, it flows in the opposite direction to the lightning current The lightning rod according to any one of claims 1, 2, and 3, wherein the induced current is returned to the mesh-shaped electric wire in the outdoor part of the building.   Between the entrance and exit of the electromagnetic shield cylindrical body is electrically connected with one or a plurality of electric wires passing through the outer periphery of the building, and when a lightning current flows through the cable, an induced current that flows in a direction opposite to the lightning current is generated. The lightning rod according to claim 1, 2 or 3, wherein the electric wire in the outdoor part of the building is refluxed.   Insulate the lightning rod on the building or the independent building up conductor, or the building side lightning arrester or the building side lightning building up conductor from the building, lay it on the roof or side of the building, and ground it from the lightning rod or the independent building up conductor Between the poles, connect with one or more shielded power cables or high-frequency coaxial cables for power, pull down the cables from the top of the building to the bottom, shield the cable near the lightning rod or the outer conductor of the coaxial cable, and ground When the shield of the cable near the pole or the outer conductor of the coaxial cable is electrically connected with a mesh-like electric wire covering the outer periphery of the building, when the lightning is induced to the lightning rod or the independent ridge raising conductor, the cable Or, the induced current flowing in the opposite direction to the lightning strike current flowing in the inner conductor of the coaxial cable is the outer conductor of the shield or the coaxial cable. Flow, characterized by being configured to further refluxed for current building outside the mesh wire, lightning rod.   Insulate the lightning rod on the building or the independent building up conductor, or the building side lightning arrester or the building side lightning building up conductor from the building, lay it on the roof or side of the building, and ground it from the lightning rod or the independent building up conductor Between the poles, connect with one or more shielded power cables or high-frequency coaxial cables for power, pull down the cables from the top of the building to the bottom, shield the cable near the lightning rod or the outer conductor of the coaxial cable, and ground When the cable shield near the pole or the outer conductor of the coaxial cable is electrically connected with one or more electric wires passing through the outer periphery of the building, when the lightning is induced to the lightning rod or the independent building up conductor, the cable Or, the induced current flowing in the opposite direction to the lightning strike current flowing in the inner conductor of the coaxial cable is the outer conductor of the shield or the coaxial cable. Flow, characterized by being configured to further refluxed for current building outside the wire, lightning rod.