WO2008026766A1 - Lightning arrestor, grounding electrode, and thunder surge voltage reducing method - Google Patents

Abstract

A lightning arrestor (1) for flowing the thunder surge current due to lightning strike (7) to the ground comprises a steel pipe (3), a conductor (4) coaxially disposed in the steel pipe (3), an a filler (10) placed between the steel pipe (3) and the conductor (4) and having a conductivity. With this, the thunder surge current flowing through the lightning arrestor (1) is divided. The low-frequency component flows through the conductor (4), and the high-frequency component flows through the steel pipe (3) outside the conductor (4) and the filler (10).

Description

Lightning arrester, ground electrode, and lightning surge voltage reduction method

Technical field

 The present invention relates to a lightning arrester, a ground electrode, and a lightning surge voltage reduction method for preventing lightning damage by flowing a lightning surge current caused by a lightning strike to the ground side.

Related. book

Background art

 If a lightning surge current with a high output flows to a building, various facilities such as traffic lights, or trees due to a lightning strike, these will be destroyed. In recent years, the number of electronic devices that are particularly vulnerable to electrical shocks has increased, and lightning damage has become a serious threat. In order to prevent such lightning damage, a conductor (usually called a lightning rod, which includes a lightning rod, a lightning conductor, etc.) that secures a path for lightning surge current due to lightning to the ground side in advance is used.

However, lightning surge currents include AC currents of a wide variety of frequencies, and when lightning surge current due to lightning strikes the lightning rod conductor, the voltage due to high-frequency components of lightning surge current becomes very large (that is, In the high-frequency component of the lightning surge current, the voltage drop V = L xdi Z dt obtained from the product of the inductance L of the enclosure and the differential component di / dt of the current becomes very large). For this reason, when V, which is the voltage drop, exceeds the insulation resistance around the conductor, dielectric breakdown occurs, spark discharge occurs around the conductor (commonly called flashover), and unexpected lightning strikes around the conductor. There is a risk of harm.

Therefore, in the lightning protection technology described in Japanese Patent Laid-Open No. 2002-186 160, In order to prevent flashover, an insulator is provided on the outer periphery of the lightning rod conductor to prevent the occurrence of flashover by making the surroundings of the lightning rod conductor completely insulated.

 However, in the lightning protection technique disclosed in this patent document, even if the insulator provided on the outer periphery of the lightning conductor is cracked or broken slightly, the insulation breaks down and a flashover occurs. In addition, the possibility of the occurrence of flashover becomes higher as the conductor length of the lightning rod conductor becomes longer. Therefore, the lightning rod conductor is required to have higher insulation resistance.

 In general, one end of the conductor is connected to a lightning rod, and is placed on top of a building or various facilities that are to be protected from lightning strikes. The other end is connected to a ground electrode buried in the ground. As a result, lightning surge currents flow in the order of lightning conductors, ground electrodes, and ground, and are diverted from buildings that are the subject of lightning damage prevention, thereby preventing damage. In grounding work, for example, the grounding resistance in class A grounding (generally called grounding impedance) is 10 Ω or less. Normally, the ground impedance is represented by an equivalent circuit consisting of resistance, inductance, and capacitance. The resistance is mainly the contact resistance with the ground of the ground electrode and the ground resistance, the inductance is the inductance of the ground electrode, and the capacitance is the capacitance between the ground electrode and the ground. In the above-described equivalent circuit, the inductance and the resistor are connected in series, and the resistor and the capacitance are connected in parallel.

In the ground impedance represented by this equivalent circuit, it must be noted that the voltage applied to the series circuit of the inductance and the resistance varies depending on the frequency component of the flowing current. That is, for DC, commercial frequency currents of 50 Hz and 60 Hz, most of the circuit voltage is added to the resistor. It is a component. On the other hand, as the frequency component of the current becomes wider, the voltage of the inductance component becomes more prominent, and the circuit voltage becomes a value in which the resistance component and the inductance component are superimposed. Therefore, this is why a high voltage equivalent to the resistance value or more is generated at the ground electrode when lightning surge current flows through the ground electrode.

 In the conventional grounding work, measures such as (1) further reducing the resistance or (2) lowering the grounding impedance are taken from the viewpoint of suppressing the potential increase of the grounding electrode against the lightning surge current. . However, these constructions require very large costs and days. In addition, the reduction in resistance in (1) above does not necessarily lead to a reduction in ground impedance and is not cost effective. In (2) above, there is a problem that this is also not cost effective, as additional work and measurement are required repeatedly until the desired value is obtained.

 If the resistance is 10 Ω, the inductance is 10 χ 、, and the lightning surge current is lOOkA and lOOkA / s, then when the lightning surge current flows through the ground electrode, 10 (Ω) X100 (kA) + 100 (k // 1 s) xlO (nH) = 1000 (kV) + 1000 (kV) = 2000 (kV). Reducing the inductance component voltage as much as possible is extremely effective in preventing dielectric breakdown of electrical equipment directly connected to the ground electrode or indirectly.

If the potential rise of the ground electrode caused by lightning surge current is large, the contact voltage and stride voltage will increase, and nearby residents and animals may get an electric shock. In addition, when two ground electrodes are grounded close to each other, if a lightning surge current flows directly to the first, the lightning surge current is also shunted to the second, and the electrical equipment connected to the ground electrode Often suffer from disasters. This is one of the typical lightning disasters of home appliances. Disclosure of the invention

 An object of the present invention is to provide a lightning arrester capable of reliably preventing lightning surge current flashover due to lightning and preventing lightning damage, a structural column having a lightning protection function, and a method of reducing lightning surge voltage. That is.

 Another object of the present invention is to prevent lightning damage caused by lightning surge currents by lowering the ground impedance of buildings and various facilities, etc., which are the targets of lightning damage prevention, in particular the above-mentioned inductance, lower than the specific value of the conductor. The present invention also provides a ground electrode, a ground electrode group, and a lightning surge voltage reduction method capable of improving cost effectiveness.

 In order to solve the above problems, according to a first aspect of the present invention, there is provided a lightning arrester for flowing a lightning surge current due to a lightning strike to the ground side, a steel pipe, a conductor coaxially arranged in the steel pipe, A conductive filler filled between the steel pipe and the conductor; a lightning surge current caused by the lightning strike is shunted; a low frequency component flows through the conductor; and a high frequency component A lightning arrester is provided, characterized by flowing through the steel pipe and the filler.

 In the above lightning arrester, the filler may contain one or more materials selected from the group consisting of a resistor, a dielectric, and a magnetic material.

 In the lightning arrester, the steel pipe and the conductor may be grounded after being terminated by a coaxial characteristic impedance.

 In the lightning arrester, the conductor, the steel pipe, and the filler may be attached to an existing facility.

Further, according to the second aspect of the present invention, there is a structural pillar having a lightning protection function of flowing a lightning surge current due to a lightning strike to the ground side, the support part having the lightning protection function, and supported by the support part, A supported portion having a function different from the lightning protection function, and the support portion having the lightning protection function A steel pipe, a conductor coaxially disposed in the steel pipe, and a conductive filler filled between the steel pipe and the conductor, and a lightning surge current caused by the lightning strike is shunted, There is provided a structural pillar having a lightning protection function, characterized in that a frequency component flows through the conductor and the high frequency component flows through the steel pipe and the filler.

 In the structural pillar having the lightning protection function, the filler may contain one or more materials selected from the group consisting of a resistor, a dielectric, and a magnetic material.

 In the structural column having the lightning protection function, the steel pipe and the conductor may be grounded after being terminated by a coaxial characteristic impedance.

 According to a third aspect of the present invention, there is provided a method for reducing a lightning surge voltage when a lightning surge current caused by a lightning strike is caused to flow to the ground side, wherein the impedance to the high frequency component of the lightning surge current is the first. A second current path lower than the first current path, and the lightning surge current is shunted so that the low-frequency component of the lightning surge current flows in the first current path and the high-frequency component flows in the second current path. Thus, there is provided a lightning surge voltage reducing method, characterized by reducing the lightning surge voltage in the first current path.

 In the lightning surge voltage reducing method, the first current path is formed of a conductor, and the second current path is a steel pipe coaxially disposed so as to cover an outer periphery of the conductor, the steel pipe, and the steel pipe The conductive material may be filled with a conductive filler.

 In the lightning surge voltage reducing method, the filler may contain one or more materials selected from the group consisting of a resistor, a dielectric, and a magnetic material.

In order to solve the above problems, according to a fourth aspect of the present invention, A ground electrode for flowing lightning surge current due to lightning as well as frequency ground fault current to the ground, at least a part of which is buried in the ground, a tubular conductor coaxially disposed in the tubular conductor, A conductive filler filled between the tubular conductor and the inner conductor, wherein a lightning surge current caused by the lightning strike is shunted, and the low-frequency component mainly flows through the inner conductor. In addition, a ground electrode is provided in which the high-frequency component mainly flows through the tubular conductor and the filler.

 In the ground electrode, the filler may contain one or more materials selected from the group consisting of a resistor, a dielectric, and a magnetic material.

 In the ground electrode, the tubular conductor and the inner conductor may be grounded after being terminated by a characteristic impedance of a coaxial system. The ground electrode is connected to a lightning arrester that sends a lightning surge current due to a lightning strike to the ground side. It may be.

 The ground electrode may be formed in a coaxial shape integrated with the lightning arrester.

 The ground electrode may be connected to a grounding device that causes a ground fault fault current of a commercial frequency power facility or power facility to flow to the ground side.

 In the ground electrode, the tubular conductor may be embedded with the axial direction set to the vertical direction.

 In the ground electrode, the tubular conductor may be embedded with the axial direction horizontal.

 In the ground electrode, the tubular conductor and the inner conductor may be connected to an equipotential bonding conductor.

According to a fifth aspect of the present invention, there is provided a ground electrode group comprising a plurality of the ground electrodes. According to a sixth aspect of the present invention, there is provided a method for reducing a lightning surge voltage when a lightning surge current caused by a lightning strike is caused to flow to the ground, wherein one end of the first current path is disposed in the ground. A second current path whose impedance to the high frequency component of the lightning surge current is lower than that of the first current path, and the low frequency component of the lightning surge current mainly flows in the first current path. The lightning surge voltage in the first current path is reduced by diverting the lightning surge current according to the frequency component so that the high-frequency component mainly flows in the second current path. A method for reducing lightning surge voltage is provided. It also functions as a conventional ground electrode in the same way as before.

 In the lightning surge voltage reducing method, the first current path is configured by an inner conductor, and the second current path is formed by a coaxial conductor disposed so as to cover an outer periphery of the inner conductor; It may be constituted by a conductive filler filled between the tubular conductor and the inner conductor.

 In the lightning surge voltage reducing method, the filler may contain one or more materials selected from the group consisting of a resistor, a dielectric, and a magnetic material.

 In the lightning surge voltage reducing method, an outer skin may be provided on the outer periphery of the coaxially arranged tubular conductor. For example, concrete can be used as the outer skin to take measures against corrosion of steel pipes when buried.

According to the present invention, when a lightning surge current caused by a lightning strike flows to the ground side through a conductor (that is, a lightning rod conductor), the lightning surge current is shunted, and the low frequency component flows through the conductor as the first current path. In addition, since the high-frequency component flows through the second current path provided around the conductor, the entire current of the lightning surge current flows through the conductor as in a conventionally known lightning arrester. Compared to T / JP2007 / 067245, it is possible to reduce the voltage drop per unit length of the conductor (that is, lightning surge voltage). As a result, it is possible to prevent the occurrence of flashover by suppressing the potential rise at the top of the conductor, and to effectively prevent lightning damage to surrounding equipment such as buried equipment.

 The ground electrode according to the present invention has an effect of reducing the ground impedance. In particular, it has a structure that reduces the inductance inherent to the ground electrode. Therefore, it has a function to suppress the rise of ground voltage when current flows not only for ground fault current of commercial frequency but also for lightning surge current. In particular, while the work for reducing ground impedance is conventionally cut-and-try, the present invention is superior in cost-effectiveness, including shortening the number of days, in that it only requires installation at the site. Yes. Further, since the inner conductor (center conductor) is electromagnetically shielded by the outer steel pipe as the tubular conductor in the ground electrode of the coaxial structure of the present invention, the ratio of the shunt surge is extremely small. The lightning disaster of electrical equipment is reduced by the effect of reducing the shunt current.

 According to the present invention, it is possible to effectively suppress an increase in the potential of the ground electrode against a lightning surge current and to realize a ground impedance that is much lower than that of the prior art. As a result, lightning surge current can be reliably sent to the ground via the ground electrode, and unforeseen situations can be prevented, such as flowing to the building side and destroying electronic equipment. In addition, even if lightning surge current that has flowed to the ground flows to other facilities in the surrounding area, other adjacent grounding electrodes, surrounding people, etc. via the ground, the lightning surge voltage at the grounding electrode is very low. Because of the value, the damage can be minimized and made safer. Brief Description of Drawings

Figure 1 shows a vertical section of a lightning arrester according to the first embodiment of the present invention. FIG.

 2 is an enlarged cross-sectional view taken along the line XX in FIG.

 Fig. 3 is an enlarged perspective view of the lightning arrester near the ground.

 Figure 4 is a circuit diagram per unit length when the lightning surge current flows through the lightning arrester.

 FIG. 5 is a partial cross-sectional view in the vertical direction of the lightning arrester according to the second embodiment of the present invention.

 FIG. 6 is a vertical cross-sectional view of a structural column according to the third embodiment of the present invention.

 FIG. 7 is an enlarged cross-sectional view taken along arrows Y—Y in FIG.

 FIG. 8 is a configuration diagram showing an example in which the ground electrode according to the fourth embodiment of the present invention is applied to a building as a lightning protection target.

 FIG. 9 is a vertical sectional view of the ground electrode.

 FIG. 10 is an enlarged cross-sectional view taken along the line XX in FIG.

 Fig. 11 is an enlarged perspective view of the ground electrode in the vicinity of the ground Fig. 12 is composed of a steel pipe, conductor and filler when a lightning surge current flowing from the upper end side of the conductor flows to the ground side FIG. 6 is a circuit diagram showing an equivalent circuit per unit length of a ground electrode according to a fourth embodiment of the present invention.

 FIG. 13 is a diagram for explaining the influence of the ground electrode according to the embodiment of the present invention on surrounding buildings. (a) shows the positional relationship between the ground electrode and its surroundings. (B) shows the relationship between the value of the lightning surge voltage (vertical axis) when the lightning surge current flows from the ground electrode to the ground and the position from the point of flow (horizontal axis).

FIG. 14 is a diagram for explaining the influence of the ground electrode according to the embodiment of the present invention on surrounding people. (A) shows the positional relationship between the ground electrode and the person around the ground electrode. (B) indicates whether the lightning surge current is grounded. The relationship between the lightning surge voltage value (vertical axis) and the position from the flow point (horizontal axis) when flowing into the ground is shown.

 FIG. 15 is a vertical sectional view of a ground electrode group having a plurality of ground electrodes according to a fifth embodiment of the present invention.

 FIG. 16 is a horizontal cross-sectional view of a ground electrode group according to a sixth embodiment of the present invention, all having four ground electrodes arranged horizontally in the tube axis direction.

 FIG. 8 is a configuration diagram showing a configuration of a ground electrode formed in a coaxial shape integrated with a lightning arrester according to a seventh embodiment of the present invention, in which a lightning surge current caused by a lightning strike flows to the ground side.

 FIG. 18 is a schematic perspective view of a coaxial cable.

 Figure 19 shows the results of trial calculation of the attenuation rate D (dB) per unit length when current of three types of frequency f flows through the conductor for each of the four types of conductance G.

Figure 20 shows four conductances G, plus G = 0 (σ = 0), and five conductances G. Three different frequencies f = 10 ⁴ , 10 ⁵ , 10 ^The figure shows the result of trial calculation of the characteristic impedance Zo of the ground electrode 1 when an alternating current of ⁶ (Hz) flows through the conductor. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is a vertical sectional view of a lightning arrester 1 according to the first embodiment of the present invention. 2 is an enlarged cross-sectional view taken along the line X— in FIG. Figure As shown in FIG. 1 and FIG. 2, the lightning arrester 1 has a configuration in which a bare conductor 4 is coaxially arranged inside an annular steel pipe 3 erected vertically on the ground 2. The steel pipe 3 is made of, for example, stainless steel. The conductor 4 is made of copper or the like, for example, and is disposed in the steel pipe 3 from the upper end side to the lower end side along the axial direction. The upper end of the conductor 4 is connected to a projecting needle 8 that protrudes slightly outside the upper end of the steel pipe 3 so as to receive a lightning strike 7. The conductor 4 is fixed at a central position in the steel pipe 3 by a plurality of insulating fixing devices 5 provided at predetermined intervals along the axial direction of the steel pipe 3.

 As shown in FIG. 2, a filler 10 having conductivity is filled between the steel pipe 3 and the conductor 4. In the present embodiment, the filler 10 is cement in which the materials of the resistor 15, the dielectric 16 and the magnetic body 17 are mixed at a predetermined ratio. As the resistor 15, for example, metal fine powder (silver powder, copper powder, etc.) or graph items are used. As the dielectric 16, a material having a relatively high dielectric constant (for example, aluminum oxide, barium titanate, etc.) is used. Further, as the magnetic material 17, for example, ferrite or the like is used. Note that the cement as the filler 10 is preferably reduced in weight, for example, by being formed into a foamed shape.

FIG. 3 is an enlarged perspective view of the lightning arrester 1 near the ground 2. As shown in Fig. 3, the lower end of the steel pipe 3 is buried in the ground 2 (here, the ground 2 is treated as the ground, but depending on the installation location, it may be a concrete structure surface) and connected to the grounding system 20 Grounded. The grounding system 20 has a configuration in which the lower ends of the steel pipe 3 and the conductor 4 in the ground are connected to the deep electrode grounding electrode 22 through the matching unit 21. The matching unit 21 is configured so that the lower ends of the steel pipe 3 and the conductor 4 are terminated by the characteristic impedance of the coaxial system formed by both of them. As a result, the lightning surge current I caused by the lightning strike 7 is It is designed to flow almost without reflection on the pole ground electrode 22. In the present embodiment, a cylindrical concrete material is used as the matching unit 21, which is arranged in parallel and concentric with the steel pipe 3 in the axial direction. A lightning arresting method according to the embodiment of the present invention performed by the lightning arrester 1 configured as described above will be described.

 When lightning 7 occurs and lightning strikes the tip 8 of the lightning arrester 1, as shown in Fig. 1, lightning surge current I, which includes a variety of frequency components, passes through the conductor 4 of the lightning arrester 1 along the axial direction. It flows from the upper end side to the lower end side. Around the conductor 4, a steel pipe 3 arranged coaxially so as to cover the outer periphery of the conductor 4 is arranged, and between the conductor 4 and the steel pipe 3, a conductive filler 10 is filled. Therefore, the lightning surge current I attenuates when it flows through the conductor 4. This phenomenon is explained below using the circuit diagram shown in Fig. 4.

 FIG. 4 shows an embodiment of the present invention constituted by the steel pipe 3, the conductor 4, and the filler 10 when the lightning surge current I that strikes the needle 8 connected to the upper end side of the conductor 4 flows to the ground side. FIG. 3 is a circuit diagram showing an equivalent circuit per unit length of the lightning arrester 1 according to the embodiment. In Fig. 4, L is the inductance of conductor 4, R is the resistance of conductor 4, and C is the capacitance between conductor 4 and steel pipe 3. G is a conductance due to the filler 10 containing the resistor 15, the dielectric 16 and the magnetic 17.

As shown in Fig. 4, the lightning surge current I attenuates when it flows through the conductor 4, and the high-frequency component I _H of the lightning surge current I passes through the filler 10 and the steel pipe 3 outside the conductor 4 (that is, This is because it flows from point A 1 to point B 2 shown in Figure 4. Therefore, the attenuated lightning surge current I flowing through the conductor 4 is the low frequency component IL of the lightning surge current I. As described above, the lightning arrester 1 according to the embodiment of the present invention is configured such that the lightning surge current I of the lightning strike 7 is divided into the low frequency component I and the high frequency component I _H, and the low frequency component JP2007 / 067245 is configured to flow through the conductor 4 as the first current path, and the high-frequency component I _H flows through the steel pipe 3 and the filler 10 as the second current path.

The lightning surge voltage V _L generated when the attenuated lightning surge current I (that is, the low-frequency component I _L of the lightning surge current I) flows through the conductor 4 is V _L = L Xd I _L / dt. This lightning surge voltage VL is the lightning surge voltage V _{L + H} = LX {d that occurs when all lightning surge currents I (= I _L + I _H ) flow through the conductor 4 as in a known lightning arrester. It is lower than (I _L + I _H ) Zdt}.

On the other hand, when the high-frequency component I _H of the lightning surge current I flows through the steel pipe 3 and the filler 10 outside the conductor 4, resistance heating is performed mainly by the resistor 15, the dielectric 16 and the magnetic substance 17 contained in the filler 10. Dielectric heating and dielectric heating occur, and part of the energy is consumed.

The low frequency component IL of the lightning surge current I flowing through the conductor 4 and the high frequency component I _H of the lightning surge current I flowing through the filler 10 and the steel pipe 3 flow to the lower end side along the axial direction and are lower than the ground 2 When it reaches the position, it flows to the grounding system 20 as shown in Fig.3. That is, the lightning surge current I flows through the matching unit 21 to the ground electrode 22 terminated by the characteristic impedance of the coaxial system.

According to the above embodiment, the lightning arrester 1 is configured as a coaxial cable in which the conductor 4 is arranged at the center of the steel pipe 3, and the conductive filler 10 is filled between the steel pipe 3 and the conductor 4. Therefore, the lightning surge current I is shunted when it flows through the conductor 4, the low frequency component IL mainly flows through the conductor 4 as the first current path, and the high frequency component I _H around the conductor 4. It can be made to flow through the second current path provided in the circuit. As a result, almost all lightning surge current I flows through conductor 4 Compared to the conventional lightning protection technology, the amount of current flowing through conductor 4 is reduced and the lightning surge voltage (L Xdi / dt) generated in conductor 4 is reduced. Can reduce 7 067245 can stabilize the lightning surge current I flowing through the conductor 4, reliably prevent the flashover that the lightning surge current I caused by the lightning strike 7 jumps out of the lightning arrester 1, and effectively prevent lightning damage. It becomes possible.

In addition, a matching unit 22 is provided in the grounding system 20, and the lower ends of the steel pipe 3 and the conductor 4 are terminated by the characteristic impedance of the coaxial system formed by the two (3, 4) and then grounded. The ground impedance is constant regardless of the earth resistivity. Further, the lightning surge current I (that is, the low frequency component IL and the high frequency component I _H ) can flow to the ground side without being reflected. As a result, the lightning surge current I can flow more reliably to the ground side, and the occurrence of flashover can be further suppressed.

 As a second embodiment of the present invention, as shown in FIG. 5, the conductor 4, the steel pipe 3, and the filler 10 may be attached to existing equipment such as a traffic light 40. FIG. 5 is a partial cross-sectional view in the vertical direction of the lightning arrester 1 according to the second embodiment of the present invention. As shown in FIG. 5, a lightning arrester constructed almost in the same manner as in the case of the first embodiment of the present invention 1 force A plurality of fixtures 45 support shafts of the traffic light 40 with a slight inclination with respect to the vertical direction. It is attached to 41. In the second embodiment, the lower ends of the steel pipe 3 and the conductor 4 are terminated with a coaxial characteristic impedance and then connected to the mesh ground electrode 52. In the second embodiment, the deep buried electrode ground electrode 22 may be used as in the first embodiment.

According to the second embodiment of the present invention, since the lightning arrester 1 is attached to existing facilities such as the traffic light 40, for example, the necessary strength and support are provided compared to the case where the lightning arrester 1 is erected independently. The design constraints related to the structure are reduced, and it is possible to easily downsize and simplify the system, and the equipment cost and equipment space of the lightning arrester 1 can be reduced. In addition, the present invention The second embodiment of 67245 also has the same effect as the first embodiment.

 As a third embodiment of the present invention, as shown in FIG. 6, the present invention may be applied to a structural pillar having a lightning protection function. FIG. 6 is a vertical sectional view of the structural column 60 according to the embodiment of the present invention. FIG. 7 is an enlarged cross-sectional view taken along arrow Y in FIG.

 As shown in FIG. 6, the structural column 60 is supported by the support 61 having the same configuration as the lightning arrester 1 according to the first embodiment of the present invention, and the support 61. And a signal device as the supported portion 62. In the third embodiment of the present invention, as shown in FIG. 6 and FIG. 7, the supported portion 6 2 is axially (ie, in the lead straight direction) between the conductor 4 of the support portion 61 and the steel pipe 3. It has a configuration in which the upper and lower ends of hollow pipes 65 arranged along the side are bent at right angles so as to protrude out of the steel pipe 3. At the upper end of the pipe 65 protruding in this way, a light emitting device 66 equipped with, for example, red, yellow and green lamps is provided. The lower end of the pipe 65 is connected to a control device (not shown) that controls the light emitting device 66 and a power supply device (not shown) that supplies power to the light emitting device 66. In the pipe 65, an electric wire group 67 such as an electric wire and a signal line for connecting the control device and the power supply device (not shown) and the light emitting device 66 are disposed. The pipe 65 is fixed with a filler 10 filled between the conductor 4 and the steel pipe 3.

 According to the third embodiment of the present invention, the structural column 60 is supported by a support part 61 having a lightning protection function and a function different from the lightning protection function supported by the support part 61 (that is, a signal In the same installation space, it is possible to establish a lightning protection function that prevents lightning damage due to lightning strikes 7 and various functions other than the lightning protection function. It is possible to save installation space. In addition, the third embodiment of the present invention has the same effect as the first embodiment.

FIG. 8 shows a grounding electrode 1 0 1 according to the fourth embodiment of the present invention. 67245 is a block diagram showing an example when applied to a building 105 as an object to be stopped. As shown in FIG. 8, on the roof of the building 105, a lightning arrester 110 as a lightning arrester is installed in the vertical direction as a lightning arrester that sends a lightning surge current from the lightning strike 107 to the ground side. A lowering lead wire 113 is connected to the lower end of the lightning rod 110 so that the lightning surge current of the lightning 107 that has fallen to the upper end can flow through the lead wire 113. The conducting wire 113 extends downward along the outer surface of the building 105, is introduced into the building 105 at a position lower than the ground 115, and is connected to a grounding part 117 provided inside the building 105. The grounding part 117 may be made of metal or the like arranged over the entire bottom part in the building 105.

 As shown in FIG. 8, the ground part 117 is connected to the ground electrode 101 and the equipotential bonding conductor 120. The potential equipotential bonding conductor 120 is connected to an electronic device 125 such as a bath computer or a metal pipe 126 such as a water pipe. In the present embodiment, electronic device 125 is connected to external power supply 127. The equipotential bonding conductor 120 is, for example, a metal plate provided so as to hold the connected electronic device 125, the metal tube 126, and the like at an equipotential. As a result, even if a lightning surge current caused by a lightning strike 7 flows, no potential difference occurs between the devices 125 and 126, thus preventing lightning damage.

FIG. 9 is a vertical sectional view of the ground electrode 101. FIG. 10 is an enlarged cross-sectional view taken along the line XX in FIG. As shown in FIGS. 9 and 10, the ground electrode 101 has a configuration in which a bare conductor 134 is coaxially arranged inside an annular steel pipe 133 embedded in the ground 115 in the vertical direction. The steel pipe 133 as a tubular conductor is made of, for example, stainless steel or a corrosion-resistant steel pipe. The conductor 134 as the internal conductor is made of, for example, copper, and is disposed in the steel pipe 133 from the upper end side to the lower end side along the axial direction. The upper end of the conductor 134 is arranged to protrude slightly outside the upper end of the steel pipe 133. Connected to part 1 17. In some cases, the conductor 134 is fixed at a central position in the steel pipe 133 by a plurality of insulating fixing devices 135 provided at predetermined intervals along the axial direction of the steel pipe 133.

 As shown in FIG. 10, a filler 140 having conductivity is filled between the steel pipe 133 and the conductor 134. In the present embodiment, as the filler 140, for example, cement in which materials of the resistor 145, the dielectric 146, and the magnetic body 147 are mixed at a predetermined ratio is used. As the resistor 145, for example, a metal fine powder (silver powder, copper powder, etc.) or a graph item is used. As the dielectric 146, a material having a relatively high dielectric constant (for example, aluminum oxide, barium titanate, etc.) is used. Further, as the magnetic body 147, for example, ferrite or the like is used. Note that the cement as the filler 140 is preferably reduced in weight, for example, by being formed in a foamed shape.

 FIG. 11 is an enlarged perspective view of the ground electrode 101 near the ground 1 15. As shown in Fig. 8, Fig. 9 and Fig. 11, the steel pipe 133 is embedded in the ground 1 15 almost along its entire length along the axial direction, but its upper end protrudes from the ground 1 15. ing. The matching unit 151 is configured so that the lower ends of the steel pipe 133 and the conductor 134 are terminated by a coaxial characteristic impedance formed by both of them (133, 134). In the present embodiment, a cylindrical concrete material is used as the matching unit 15 51, which is arranged in parallel and concentrically with the steel pipe 133 in the axial direction.

 A lightning surge voltage reduction method according to the fourth embodiment of the present invention, which is performed by the ground electrode 101 configured as described above, will be described.

As shown in Figure 8, when lightning 107 occurs and lightning strikes the top of the lightning arrester 1 10 that is a lightning arrester, lightning surge current I flows down from the bottom of the lightning arrester 1 10 to the conducting wire 1 13 Next, it flows from the conductive wire U 3 to the ground electrode 10 1 . This lightning surge current I contains many frequency components. The lightning surge current I flowing to the ground electrode 101 flows from the upper end side to the lower end side along the axial direction of the conductor 134 of the ground electrode 101 in FIG. Around the conductor 134, a steel pipe 133 is arranged coaxially so as to cover the outer periphery of the conductor 134, and between the conductor 134 and the steel pipe 133, a conductive filler 140 is filled. Therefore, the lightning surge current I attenuates as it flows through the conductor 134. This phenomenon will be described below with reference to the circuit diagram shown in FIG.

 FIG. 12 shows the ground electrode according to the fourth embodiment of the present invention, which is composed of the steel pipe 133, the conductor 134, and the filler 140 when the lightning surge current I flowing from the upper end side of the conductor 134 flows to the ground side. FIG. 6 is a circuit diagram showing an equivalent circuit per unit length of 101. In FIG. 12, L is the inductance of the conductor 134, R is the resistance of the conductor 134, and C is the capacitance between the conductor 134 and the steel pipe 133. G is a conductance caused by the filler 140 containing the resistor 145, the dielectric 146, and the magnetic material 147.

When the lightning surge current I flows through the conductor 134, the current I _H mainly composed of the high-frequency component of the lightning surge current I is applied to the filler 140 and the steel pipe 133 outside the conductor 134 (that is, the points shown in FIG. 12). Easy to flow from A1 to point B2. Therefore, the lightning surge current flowing in the conductor 134 is IL mainly composed of a low frequency component obtained by subtracting I _H from the lightning surge current I. As described above, the ground electrode 1 according to the first embodiment of the present invention has the lightning surge current of the lightning 107.

I is divided into a low-frequency component II and a high-frequency component I _H , the low-frequency component IL mainly flows through the conductor 134 as the first current path, and the high-frequency component I _H is mainly the steel pipe as the second current path 133. And the filler 140 is configured to flow.

The approximate lightning surge voltage generated when the attenuated lightning surge current I (that is, the low-frequency component IL of the lightning surge current I) flows through the conductor 134 is V _L = L XdI _L Zdt. This lightning surge voltage V _L is conventionally known. Lightning surge voltage V _{L + H} = LX {d (I _L + I _H ) Zdt}, which occurs when lightning surge current I (= IL + I _h ) flows through conductor 34, like ground electrode Has been.

On the other hand, when the high-frequency component I _H of the lightning surge current I flows through the steel pipe 133 and the filler 140 outside the conductor 134, the resistance is mainly caused by the resistance antibody 35, the dielectric 136 and the magnetic substance 137 contained in the filler 140. Heating, dielectric heating, and induction heating occur, and part of the energy is consumed.

The main components of the low-frequency component IL of the lightning surge current I flowing through the conductor 134 and the high-frequency component I _H of the lightning surge current I flowing through the filler 140 and the steel pipe 133 flow to the lower end side along the axial direction. When it reaches a lower position, as shown in FIG. 10, it flows out to the ground 115 through the matching unit 151, and a part of it flows out to the ground 115 from the portion in contact with the steel pipe 133. According to the above embodiment, the ground electrode 101 is configured as a coaxial cable in which the conductor 134 is disposed at the center of the steel pipe 133, and the conductive filler 140 is filled between the steel pipe 133 and the conductor 134. As a result, the lightning surge current I is shunted when flowing through the conductor 134, the low-frequency component I flows mainly through the conductor 134 as the first current path, and the high-frequency component I _H mainly flows through the conductor 134. It is possible to flow through a second current path provided around the. This reduces the amount of current flowing through the conductor 134 and reduces the lightning surge voltage (L XdiZdt) generated in the conductor 134, compared to the case of the conventionally known ground electrode in which almost all the lightning surge current I flows through the conductor 134. The ground impedance can be made lower than before. As a result, the diversion flow that flows to the building side is reduced, and as a result, the situation such as the destruction of electrically connected electronic devices is reduced.

In addition, as described above, the lightning surge voltage caused by the ground electrode 101 is reduced, so that the lightning surge that flows to the ground 115 via the ground electrode 101 is reduced. It is possible to minimize damage to the surrounding buildings and human beings. Hereinafter, the effect will be described with reference to examples shown in FIGS.

 In the example shown in FIG. 13 (a), another building 155 exists near the building 105 having the ground electrode 101. The other building 155 includes, for example, an electronic device 165 connected to an external power source 167, for example. The other building 155 is grounded by a conventionally known ground electrode 161 embedded in the ground 115. The ground electrode 161 is connected to the electronic device 165 via the conductive wire 160. Fig. 13 (b) shows the lightning surge voltage in the ground 115 when the lightning surge current I flows from the ground electrode 101 to the ground 115 when the lightning 107 falls on the building 105 shown in (a). Is a graph showing the value of with the position on the ground 115. In (b), the vertical axis represents the lightning surge voltage value, and the horizontal axis represents the position (ie, distance) on the ground 115. The horizontal positional relationship of (a) corresponds to the distance indicated by the horizontal axis of (b). When the building 105 shown in (a) has a conventionally known ground electrode instead of the ground electrode 101, the relationship between the lightning surge voltage and the distance is as shown by the dotted line in (b).

As shown in Fig. 13 (b), when a conventionally known ground electrode is used, the initial value of the lightning surge current voltage (lightning surge voltage) when flowing to the ground 115 is UE _Q , but infinite. When the ground electrode 101 of the present invention is used with the far point potential set to zero, the value of the lightning surge voltage flowing to the ground 115 is greatly reduced, and the lightning surge voltage immediately after flowing to the ground 115 is reduced. The initial value is U _{E 1} . In general, the lightning surge voltage gradually attenuates as it travels to a position (distance) farther away from the point where the ground 115 is passed, but when a conventionally known ground electrode is used for the building 105, The lightning surge voltage at point D of the adjacent ground electrode 161 is still a very high value U _D Q. 165 may be damaged. On the other hand, when the ground electrode 101 according to the present invention is used, the lightning surge voltage at the point D of the adjacent ground electrode 161 becomes a sufficiently low value U _{D 1} and the electronic device 165 is not damaged. . Thus, according to the present invention, it is possible to reduce or eliminate the damage caused by lightning surge voltage on the adjacent ground electrode 161. On the other hand, the ground electrode of the building 105 is not the ground electrode 101 of the present invention, but is conventionally known. When the ground electrode 161 is used, the initial value of the lightning surge current voltage (lightning surge voltage) when flowing to the ground is υ _{よ う} , as shown by the dotted line in Fig. 13 (b). However, if the ground electrode 101 of the present invention is used as the adjacent ground electrode, the steel tube portion 133 is not in contact with the ground 115 but the conductor, and the center conductor 134 is not in direct contact with the ground 115 as in the known ground electrode. Therefore, since the steel pipe portion 133 acts as an electromagnetic shield for the central conductor 134, intrusion of lightning surge current into the central conductor 134 is suppressed. In addition, since the current of the low frequency component selectively flows through the center conductor 134 due to its property, the current surge voltage is greatly reduced.

Next, we will use Fig. 14 to explain that the damage to the surrounding people is minimized. In the example shown in FIG. 14 (a), a pedestrian 170 walking near the building 105 with the ground electrode 101 is shown. Figure 14 (b) shows the value of lightning surge voltage in the ground 115 when the lightning surge current I flows from the ground electrode 101 to the ground 115 when the lightning 107 falls on the building 105 shown in (a). Is a graph showing the position along the ground 115. In (b), the vertical axis represents the lightning surge voltage value, and the horizontal axis represents the position on the ground 115 (ie, the distance). The horizontal positional relationship in (a) corresponds to the distance indicated by the horizontal axis in (b). When the building 105 shown in (a) has a conventionally known ground electrode instead of the ground electrode 101, the relationship between the lightning surge voltage and the distance is (b ) As shown in the dotted line.

As shown in Fig. 14 (a) and (b), when a conventionally known ground electrode is used, the initial value of the lightning surge current voltage (lightning surge voltage) when flowing to the ground 115 is U _EQ . On the other hand, when the ground electrode 101 of the present invention is used, the value of the lightning surge voltage flowing through the ground 115 is greatly reduced, and the initial value of the lightning surge voltage immediately after flowing through the ground 115 is U _{E 1} . It has become. As a result, the lightning surge voltage gradient (solid line (b)) when the ground electrode 101 of the present invention is used is the lightning surge voltage gradient (dotted line (b)) when the conventionally known ground electrode is used. It has become more gradual.

As shown in Fig. 14 (a), both feet of the pedestrian 170 are in contact with the ground 115 at different positions L l and L 2, so that the lightning surge current that flows from the ground electrode 101 to the ground 115 When it flows to the ground 115 immediately below the pedestrian 170, a lightning surge voltage (referred to as stride voltage) corresponding to the potential difference between both feet is applied to the pedestrian 170. However, when the ground electrode 101 of the present invention is used, the slope of the lightning surge voltage is moderated as described above, and therefore, between the position L 1 of one foot and the position L 2 of the other foot. The potential difference is reduced to a significantly low value from U _{S 1} and the potential difference U _{S ()} when a conventionally known ground electrode is used. Thus, according to the present invention, even when a lightning surge current flows through pedestrian Π0, it is possible to effectively reduce the damage.

 In the above-mentioned example, the electric shock due to the lightning surge current of the pedestrian 170 has been described. However, as shown in FIG. 14 (a), the contact person who is in direct contact with the building 105 by using the ground electrode 101 of the present invention. 171 electric shock damage can be effectively reduced or made harmless.

For example, as shown by the dotted line in Fig. 14 (b), when a conventionally known ground electrode is used, the lightning surge voltage (referred to as the contact voltage) received when the contact person 171 receives an electric shock is Position W and contact 171 position This is the potential difference U _TG with L 0, which is significantly larger than the potential difference U _{S () received} by the pedestrian 170 described above. However, when the ground electrode 101 of the present invention is used, as shown by the solid line in FIG. 14 (b), the lightning surge voltage is sufficiently reduced and the attenuation level is moderated. In this case, the applied potential difference U _{T 1} is very low. As described above, according to the present invention, even when a lightning surge current flows, it is possible to effectively reduce the electric shock damage of the contact person 171.

 Furthermore, as described above, the ground electrode 101 having a coaxial structure can basically reduce the inductance component of the conventional ground electrode significantly, thereby reducing the ground impedance value. Become. Among the ground impedances, there is an advantage that the value of the reactance component does not depend on the normal soil environment (for example, resistivity) in which the ground electrode 101 is installed. In addition, when installing the ground electrode 101 in the building 105, etc., which is the target of lightning damage prevention, the manufactured ground electrode 101 is transported to the site where the installation location (for example, the building 105, etc.) is located and along the vertical direction. After excavating a hole, the ground electrode 101 can be inserted and fixed in this hole, and the operation can be performed very easily. Furthermore, as described above, since the ground electrode 101 has a coaxial structure, the steel pipe 133 of the ground electrode 101 can shield the current from the outside and protect the conductor 134. This prevents a situation where the induced lightning surge current flows from the ground 115 into the conductor 134. In addition, for example, when another ground electrode is provided adjacent to the ground electrode 101, a lightning surge current flowing from the other adjacent ground electrode to the ground 115 flows into the center conductor 134 of the ground electrode 1. The amount can be reduced.

As a fifth embodiment of the present invention, as shown in FIG. 15, a plurality of ground electrodes 101 having different characteristic impedances are connected to each other, and ground electrode group 1 02 may be formed. FIG. 15 is a cross-sectional view showing a vertical cross section of a ground electrode group 102 having three ground electrodes 101 as an example. In the example of the ground electrode group 102 shown in FIG. 15, three ground electrodes 101 are embedded in the ground 115 at substantially equal intervals from each other with the tube axis direction of the steel pipe 133 as a tubular conductor being vertical. . The conductors 134 of the three ground electrodes 101 are connected to each other outside the steel pipes 133 to become one. The conductors 134 joined together in this way are connected to a lightning arrester 110 provided at the upper part of the building 105 via, for example, a grounding part 117 shown in FIG. According to the fifth embodiment of the present invention, since a plurality of ground electrodes 101 are used, each ground electrode 101 can be made smaller than before. This greatly facilitates the transportation and construction of each ground electrode 101. Note that the fifth embodiment also has the same effect as the fourth embodiment.

As a sixth embodiment of the present invention, as shown in FIG. 16, when a plurality of ground electrodes 101 having different characteristic impedances are installed, the tube axis direction may be horizontal and buried in the ground 115. FIG. 16 is a cross-sectional view showing a horizontal cross section of a ground electrode group 102 having four ground electrodes 101 as an example. In the example of the ground electrode group 102 shown in FIG. 16, the four ground electrodes 101 are all arranged in the same horizontal plane with the tube axis direction of the steel pipe 133 as a tubular conductor being horizontal. The four ground electrodes 101 are arranged radially so that the directions of the tube axes are perpendicular to each other. Each ground electrode 101 is arranged with the end on the side where the conductor 134 as an internal conductor extends outside the steel pipe 133 facing the center of radiation. In the sixth embodiment of the present invention, a hollow space 180 is provided at the center of the radial ground electrode group 102, and the conductors 134 of the four ground electrodes 101 are connected to each other in the space 180. It is one. The conductors 34 joined together in this way are extended upward along the vertical direction, for example, It is connected to a lightning arrester 110 provided at the upper part of the building 105 via a grounding part 117 shown in FIG.

 According to the sixth embodiment of the present invention, by arranging the tube axis direction of the steel pipe 133 of the ground electrode 101 horizontally, for example, when embedding the ground electrode 101, holes formed in the ground 115 have the same depth. The construction will be facilitated, such as better. In addition, when a plurality of ground electrodes 101 are connected to form the ground electrode group 102, the end portions of the ground electrodes 101 on the side where the lightning surge current flows can be arranged away from each other. The impact can be reduced. Note that the sixth embodiment also has the same effect as the fourth embodiment.

 As a seventh embodiment of the present invention, as shown in FIG. 17, a lightning arrester 110 and a ground electrode 101 for flowing a lightning surge current due to a lightning strike 107 to the ground side may be formed in a single coaxial shape. FIG. 8 is a vertical cross-sectional view of an upright lightning rod 185 as an example in which the lightning arrester 110 and the ground electrode 101 are formed in a body-shaped coaxial shape. In the example shown in FIG. 16, the lightning rod 185 is erected independently and has a protruding needle 186 at the upper end. The lightning protection device and the ground electrode may be integrated and provided in the existing equipment. For example, if this configuration is used by connecting to the overhead ground wire of the transmission line and connecting the upper end of the ground electrode to the overhead ground wire, the rise in lightning surge voltage of the overhead ground wire can be reduced.

According to the seventh embodiment of the present invention, since the lightning surge current caused by the lightning strike 107 flows through the coaxial lightning arrester 110 before it reaches the ground electrode 101, the potential increase of the lightning surge current is more effectively suppressed. The ground impedance can be greatly reduced. In addition, in all the routes from the lightning surge current flowing from the lightning arrester 110 to the ground 115 via the matching device 151 (that is, the route flowing in the atmosphere above the ground 115 and the route in the ground 115) Discharge such as flashover caused by lightning surge current Can be prevented. Furthermore, it is possible to prevent current from flowing into this path from the outside. Note that the seventh embodiment also has the same effect as the fourth embodiment.

 As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to the example which concerns. It is obvious that a person skilled in the art can come up with various changes or modifications within the scope of the technical idea described in the scope of the patent claims. It is understood that it belongs to the scope.

 In the embodiment, the case where steel pipes 3, 133 made of stainless steel or anti-corrosion steel pipe, for example, is used as the tubular conductor has been described. However, tubular conductors made of other materials may be used. .

 In the embodiment, a description has been given of a case where cement is used as the fillers 10 and 140, in which the resistors 15 and 145, the derivatives 16 and 146, and the magnetic bodies 17 and 147 are mixed at a predetermined ratio, respectively. However, the fillers 10 and 140 may use any conductive material. The fillers 10 and 140 may contain one or more materials selected from the group consisting of resistors, derivatives, and magnetic materials. Furthermore, materials other than these resistors, dielectrics, and magnetic materials may be included.

 In the embodiment, the case where the resistors 15 and 145 are metal fine powder (silver powder, copper powder, or the like) or a graph item has been described, but other materials may be used as the resistors 15 and 145.

 In the embodiment, the case where the dielectrics 16 and 146 are aluminum oxide and barium titanate has been described. However, other materials may be used as the dielectrics 16 and 146.

In the embodiment, the case where the magnetic bodies 17 and 147 are ferrites has been described. However, materials other than these are used as the magnetic bodies 17 and 147. May be.

 In the embodiment, a description has been given of the case where a cylindrical concrete material is used as the matching unit 22, 151, which is arranged in parallel and concentrically with the steel pipes 3, 133. However, the matching unit 22, 151 May be any material and shape for impedance matching. In the first to third embodiments, the case where the grounding electrode of the grounding system 20 is the deep buried electrode grounding electrode 22 or the mesh grounding electrode 52 has been described, but other grounding electrodes may be used.

 In the third embodiment, the case where the supported portion 62 has a traffic light function has been described. However, the supported portion 62 has a function other than the lightning protection function, such as a communication function and an illumination function. May be.

 In the fourth to seventh embodiments, the case where the ground electrode 101 of the present invention is used alone has been described. However, for example, it may be used in combination with a conventionally known ground electrode such as a mesh ground electrode. This has the effect of reducing the ground impedance of the ground electrode.

 Although the case where the ground electrode group 102 has three or four ground electrodes 101 has been described in the fifth embodiment, any number of ground electrodes 101 may be included. Further, the plurality of ground electrodes 101 included in the ground electrode group 102 may have any arrangement configuration.

 In the seventh embodiment, the case where the lightning arrester 110 and the ground electrode 101 are formed in an integral coaxial shape has been described. However, between the coaxial lightning arrester 110 and the coaxial ground electrode 101, For example, a bellows-shaped coaxial or non-coaxial intermediate portion may be provided, and the lightning arrester 110 and the ground electrode 101 may be connected via the intermediate portion.

In the fourth to seventh embodiments, the case where the ground electrode 101 exerts an effect on the lightning surge current caused by the lightning strike 107 has been described. However, the ground electrode 101 includes, for example, the electric device 125 shown in FIG. In case of a fault Even if it is the same, the effect is similar to the effect against lightning surge current flow against leakage current flow at commercial frequency frequency. It is possible to achieve this effect. .

 In the 44th to 77th practical embodiments, the grounded ground electrode electrode 110011 is directly and directly connected to the ground 111155. Although it has been explained in the case where it is buried, it has been explained in the case of the outer circumference of the contact ground electrode electrode 110011. For example, a cement etc. It's okay to have an outer and outer skin. . In this way, an outer skin can be provided on the outer periphery of the steel pipe tube 113333 so that the grounded earth electrode electrode 110011 This can be done by taking countermeasures against corrosion corrosion of the steel pipe tube 113333 at the time of burial. . Example of actual implementation

 In general, the main major frequency component of the lightning surge current flow is considered to be 1100 KKHHzz ~ ~ 11 MMHHzz. The lightning arrester device 11 and the grounded ground electrode electrode 110011 relating to the form of implementation of the invention are generally used in a general transmission transmission type. From the analysis of the positive sine wave using the steady-state normal current method, the trial calculation using the equation is applied appropriately. It verifies the effectiveness of its effectiveness. .

 As described above, the lightning arrester device 11 and the grounded electrode electrode 110011 are connected to the lossy loss line shown in Figs. 44 and 1122. Since it can be regarded as an equivalent equivalent circuit circuit of the track, in the following, a trial calculation is made by appropriately applying one general formula of publicly known knowledge. Do arithmetic. . It should be noted that the resistance resistance RR and the conductance GG are set to 00 and set to 00 in the equivalent equivalent circuit of the lossy and broken line. In such a case, it falls under the equivalent equivalent circuit path of a lossless lossless line. .

 Generally, as shown in FIG. 1188, the inner and outer conductors 9911 have outer and outer diameters of aa and 9911, respectively. The coaxial shaft cable 9955, whose inner diameter is bb, has an inner air conductor 9911 and an outer outer conductor 9922 that are insulated with air and air. If the electric current of the frequency of the frequency ((HHzz)) is applied, the coaxial cable cable is used. Inductor inductance LL ((ii HH // mm)), capacitance capacitor CC ((ppFF // mm)) and resistance per unit length of 9955 Resistance resistance RR

((ΩΩ // mm)),, and ピ ピ ー ΖΖ ((ΩΩ)) are the following formulas ((11)) to ((44)) This is a publicly known knowledge. .

CC == ((5555..66XX εε ss)) // {{IInn ((bb // aa))}} ((22)) R = {4.15 X 10 " ⁸ X (a + b) X Λ f} / (a X b) · (3)

Zo = 60X In (b / a) (4) In the above equation (2), ε s is the dielectric constant.

The polyethylene was filled instead of air between the inner conductor 91 and outer conductor 92 of the coaxial cable 95 shown in FIG. 18, when a current is flowed in the frequency ^{i = 3 X 10 9 (Hz} ) to a coaxial cable 95 Shows that the conductance G (S / m) of the coaxial cable 95 can be obtained by the following equation (5).

 G = (7.35X 10- '°) / {In (b Z a)} (5) However, in the present invention, the filler 10 between the conductor 4 of the lightning arrester 1 and the steel pipe 3, or the ground electrode 101 The filler 140 between the conductor 134 and the steel pipe 133 is dominated by conductivity, so that the conductance G of the lightning arrester 1 or ground electrode 101 is less than the conductivity σ (S Zm) of the filler 10 or 140. Therefore, it is appropriate to calculate by the following formula (6).

G = (σ X 2 7t) / {In (b / a)} (6) Table 1 shows various conductivity σ as filler 1 or 140 (containing resistor, dielectric and magnetic) When the substance of (S / m) is used, each value of the conductance G (S Zm) of the lightning arrester 1 or the ground electrode 101 calculated from the above equation (6) is shown. In Table 1, the inner conductor 91 has an outer diameter of a = 10 (mm) and the outer conductor 92 has an inner diameter of b = 1000 (mi). table 1

Now, in the equivalent circuit shown in Fig. 412, ァ shown in the following equation (7) is generally called the propagation coefficient.

 7 = {(R + j ω L) X (G + j ω C)} (7) where ω (radZ s) 'is the angular frequency of the current flowing through the equivalent circuit, and C = 2 T f. When r = + j β (8) and α] 6 are set, the ratio of the voltage component of the inner conductor 91 to the outer conductor 92 when current flows through the equivalent circuit for 1 (m) is expressed by the following equation (9). It is known that it can be obtained.

I {v (x) / y (x + 1)} I = e ^{ffi 1} (9) However, assuming that current flows 1 (m) from the position x to the position (x + 1), the position X The value of the voltage component of V (X), position (x + 1

) Is the voltage component value V (+ 1). As a result, the attenuation factor D (d

B) is obtained by the following equation (10).

D = 20X log, 0 e ^{α 1}

W

= 8.686 X (1) (10) Therefore, the values of L, C, R and G obtained from the above equations (1) to (3) and (6) are substituted into the above equation (7), and the propagation coefficient After calculating the value of Eq. (8), the voltage value of the lightning surge current flowing through the lightning arrester 1 or the conductor 4 or 134 of the ground electrode 101 can be calculated from the above formula (8). The attenuation factor D (dB) can be obtained. The above equation (10) is for the voltage component, but the same applies to the current decay rate.

The calculation here assumes that the outer diameter of conductor 4 or 134 is 10 (mi) and the inner diameter of steel pipe 3 or 133 is 1000 (mm). Therefore, by applying a = l 0 and b = 1000 to the above formulas (1) and (2), the inductance L and capacitance C of the lightning arrester 1 or ground electrode 1 can be expressed as L = l (HH / m), C = 12 (pF / m). Also, referring to Table 1, the conductance G value that is optimal for the estimation is G = 0.01, 0.1, 1.0, 10.0 (S / m) (that is, conductivity σ = 0.00733, 0.0733, 0.7 33, 7.33 ( Set to S / m)) for trial calculation. Figure 19 shows the lightning surge currents at three frequencies f = 10 ⁴ , 1 0 ⁵ , 10 ⁶ (Hz) for each of these four types of conductance G. The conductor 4 of the lightning arrester 1 or the ground electrode 101 It shows the result of trial calculation of the attenuation factor D (dB) per unit length when flowing through the conductor 134.

As shown in Fig. 19, the attenuation factor D (dB) of the lightning surge current flowing through the conductor 4 or 134 as the value of the conductance G (ie, conductivity) increases (within a range that is not extremely large as the conductance of the metal). ) Increases. Therefore, when the lightning arrester 1 or the ground electrode 101 is configured as a coaxial cable as in the present invention, and the conductivity σ is increased so that the filler 10 or 140 has the resistor 15 or 145, Lightning surge current flowing through conductor 4 or 134 is relatively reduced It can be seen that the effect is diminished and diverted by the outside of the inner conductor (ie, filler and steel pipe).

As shown in Fig. 19, when G = 0.01 (S / m) (ie, conductivity σ = 0.00733 (S Zm)), the attenuation factor D is the lightning frequency f = 10 ⁴ (Hz). Lightning surge current of D = 0.2 (dB), frequency f = 10 ⁵ (Hz) Lightning surge current of D -0.5 (dB), frequency f = 10 ⁶ (Hz) D = l.5 (dB ) This indicates that, among the lightning surge currents flowing through the inner conductor, the higher frequency components with higher frequency are attenuated and shunted by the outside of the inner conductor (ie, filler and steel pipe).

Figure 20 shows the three types of frequency: f = 10 ⁴ , 10 ⁵ , for each of the five types of conductance G by adding the value of G = 0 (σ = 0) to the above four types of conductance G. The figure shows the results of trial calculations of the characteristic impedance Zo of the lightning arrester 1 or ground electrode 1 when a lightning surge current of 10 ⁶ (Hz) flows through the conductor 4 or 134 using the above equation (4). is there. This corresponds to the resistance of the matcher.

FIG. 20 is a graph giving a guide to the matching impedance of the present invention. In the case of lossless (G = 0 (σ = 0)), the characteristic impedance Zo is 288.7 (Ω) as shown in Fig. 20. It is well known that the characteristic impedance is constant regardless of frequency when it is lossless, and this means that the matching resistance is 288.7 (Ω) when lossless. Means that it is consumed at the end without disturbing the voltage-current characteristics. On the other hand, in the case of loss, the characteristic impedance differs depending on the value of conductance G (ie, dielectric constant σ) shown in Fig. 20, and also depends on the frequency. This is the matching impedance. As shown in FIG. 20, the impedance Zo of the lightning arrester 1 or the ground electrode 101 is the conductance G (that is, the conductive The larger the value of the rate σ), the lower the impedance Ζο of the lightning arrester 1 or the ground electrode 1 is less than 288.7 (Ω) in the case of no loss (G = 0 (σ = 0)) Therefore, a guideline for consistent impedance is obtained.

 Next, when the ground electrode 101 according to the fourth to seventh embodiments of the present invention is used, how much the value of the lightning surge voltage is reduced as compared with the case where the conventionally known ground electrode is used. Try to calculate if you can. In this trial calculation, it is assumed that the ground electrode of the present invention is a coaxial cable in which the outer diameter of the conductor 134 of the ground electrode 101 shown in FIG. 8 is 10 (mm) and the inner diameter of the steel pipe 133 is 1000 (mm). In other words, a = 10 and b = 1000 in Fig.18. On the other hand, it is assumed that the conventionally known ground electrode is a cable in which a conductor having an outer diameter of 10 (mm) is exposed without having a steel pipe. Assuming that the atmospheric region where the lightning surge current flows is handled by the coaxial model, assuming that the outer radius is 50 (m), the grounding electrode of the present invention assumed as above in Fig. 18 is a = 10 and b = 50000. 101 and a known ground electrode, when a current with a frequency of 1 (MHz) and a magnitude of 20 (kA) flows a distance of 5 (m) along the cable axis. Calculate each lightning surge voltage specifically. As described above, the conductance L of the ground electrode 1 of the present invention can be obtained as L = l (pi H / m) from the above equation (1). Similarly, when the conductance L of the conventionally known ground electrode is obtained from the above equation (1), L = 1.7 (// H / m), which is about twice as large.

 First, assuming that all current flows through the conductor, the lightning surge voltage V can be calculated from the following equation (11) as the voltage generated between the cables.

V = j X ω XLXI (11) That is, when the ground electrode 1 of the present invention, the lightning surge voltage V becomes v = 2 π X 1 X 10 6 X 1 X 10 "6 X 20 X 10 3 = 600 (kV). In contrast In the case of a conventionally known ground electrode, the conductance L value is about 1.7 times, so the lightning surge voltage V is also 1.7 times, that is, v = 1020 (kv), which is a very high value. .

 Furthermore, in the ground electrode 1 of the present invention, when G = 1.0 (S / m), as shown in Fig. 19, the lightning surge voltage is attenuated per unit length by the shunt effect D = 15 (dB ) When the lightning surge current flows 5 (m) along the axial direction, the attenuation rate becomes D = 5 X 15 = 75 (dB). Since 75 (dB) is equivalent to 1/1000 or less, the lightning surge voltage V when the ground electrode 1 of the present invention is used is 600 (kV) assuming that the frequency is 1 (MHz). It is theoretically calculated that it is suppressed to 1/1000 or less, that is, v = 1 (kV).

 Note that the lightning surge voltage described above corresponds to the lightning surge voltage generated at the outlet end of the ground electrode 1. Therefore, since this value is low, the influence of lightning surge voltage on the surroundings can be made very small, and the contact voltage and stride voltage can be reduced to effectively reduce the electric shock accident disaster. Become. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is particularly useful for a lightning arrester and a grounding electrode that prevent lightning damage by flowing a lightning surge current caused by a lightning strike to the ground. For example, lightning arresters such as power distribution poles in the power system field, ground electrodes, lightning arresters such as overhead support poles in the electric railway field, ground electrodes, lightning arresters such as road lighting pillars and traffic signal pillars in the road field , Ground electrodes, ground electrodes for antennas of mobile communication base poles in the information communication field, surveillance cameras, etc. It is very useful for lightning devices, grounding electrodes, lightning protection devices such as various manufacturing factories and storage facilities in the engineering field, and grounding electrodes.

Claims

The scope of the claims

1. A lightning arrester that sends a lightning surge current from lightning to the ground side,

 A conductor arranged coaxially in the steel pipe;

 A conductive filler filled between the steel pipe and the conductor; and

 A lightning arrester, wherein a lightning surge current caused by a lightning strike is shunted, a low frequency component thereof flows through the conductor, and a high frequency component thereof flows through the steel pipe and the filler.

 2. The lightning arrester according to claim 1, wherein the filler contains one or more materials selected from the group consisting of a resistor, a dielectric, and a magnetic material.

 3. The lightning arrester according to claim 1 or 2, wherein the steel pipe and the conductor are grounded after being terminated by a characteristic impedance of a coaxial system.

 4. The lightning arrester according to any one of claims 1 to 3, wherein the conductor, the steel pipe, and the filler are attached to an existing facility.

 5. A structural pillar with a lightning protection function that sends lightning surge current due to lightning to the ground side,

 A support portion having a lightning protection function;

 A supported part supported by the support part and having a function different from the lightning protection function;

The support portion having the lightning protection function includes a steel pipe, a conductor coaxially arranged in the steel pipe, and a conductive filler filled between the steel pipe and the conductor, and a lightning surge caused by the lightning strike. The current is shunted, A structural column having a lightning protection function, wherein a low frequency component flows through the conductor, and a high frequency component flows through the steel pipe and the filler.

 6. The structural pillar having a lightning protection function according to claim 5, wherein the filler contains one or more materials selected from the group consisting of a resistor, a dielectric, and a magnetic material.

 7. The structural pillar having a lightning protection function according to claim 5, wherein the steel pipe and the conductor are grounded after being terminated by a characteristic impedance of a coaxial system.

 8. A method of reducing lightning surge voltage when lightning surge current caused by lightning strikes to the ground side,

 Providing a second current path whose impedance to the high frequency component of the lightning surge current is lower than that of the first current path;

 By dividing the lightning surge current so that the low-frequency component of the lightning surge current flows in the first current path and the high-frequency component flows in the second current path, the lightning surge in the first current path A method of reducing lightning surge voltage, characterized by reducing voltage.

 9. The first current path comprises a conductor,

 The second current path is composed of a steel pipe coaxially arranged so as to cover the outer periphery of the conductor, and a conductive filler filled between the steel pipe and the conductor. The lightning surge voltage reduction method according to claim 8, characterized in that it is characterized in that:

 10. The lightning surge voltage reduction method according to claim 8, wherein the filler contains one or more materials selected from the group consisting of a resistor, a dielectric, and a magnetic material.

 1 1. A grounding electrode that carries lightning surge current from lightning to the ground, and at least a part of the tubular conductor buried in the ground,

An inner conductor coaxially disposed within the tubular conductor; A filler filled between the tubular conductor and the inner conductor and having conductivity with respect to a high-frequency component;

 A ground electrode, wherein a lightning surge current caused by a lightning strike is shunted, a low-frequency component mainly flows through the inner conductor, and a high-frequency component mainly flows through the tubular conductor and the filler.

 12. The ground electrode according to claim 11, wherein the filler contains one or more materials selected from the group consisting of a resistor, a dielectric, and a magnetic material.

 13. The ground electrode according to claim 11 or 12, wherein the tubular conductor and the inner conductor are grounded after being terminated by a characteristic impedance of a coaxial system.

 14. The grounding electrode according to any one of claims 11 to 13, wherein the grounding electrode is connected to a lightning arrester that sends a lightning surge current caused by a lightning strike to the ground side.

 15. The ground electrode according to claim 14, wherein the ground electrode is formed in a coaxial shape integrated with the lightning arrester.

 16. The ground electrode according to any one of claims 11 to 15, wherein the tubular conductor is embedded with the axial direction being a vertical direction.

 17. The ground electrode according to any one of claims 11 to 16, wherein the tubular conductor is embedded with the axial direction being a horizontal direction.

 18. The ground electrode according to any one of claims 11 to 17, wherein the tubular conductor and the inner conductor are connected to an equipotential bonding conductor.

 19. A ground electrode group comprising a plurality of ground electrodes according to any one of claims 11 to 18.

20. A method of reducing lightning surge voltage when a lightning surge current caused by lightning strikes the ground. A first current path is provided so that one end of the first current path is disposed in the ground, and a second current path having a lower impedance than the first current path is provided for the high-frequency component of the lightning surge current.

 The lightning surge current is shunted according to the frequency component so that the low frequency component of the lightning surge current mainly flows in the first current path and the high frequency component mainly flows in the second current path. A method of reducing lightning surge voltage, characterized by reducing lightning surge voltage in the current path.

 2 1. The first current path comprises an inner conductor,

 The second current path is composed of a tubular conductor arranged coaxially so as to cover the outer periphery of the inner conductor, and a conductive filler filled between the tubular conductor and the inner conductor. The method for reducing a lightning surge voltage according to claim 20, wherein the lightning surge voltage is reduced.

 2 2. The lightning surge voltage reduction method according to claim 21, wherein the filler contains one or more materials selected from the group consisting of a resistor, a dielectric, and a magnetic material.

 23. The method of reducing lightning surge voltage according to claim 21 or 22, wherein an outer skin is provided on an outer periphery of the coaxially arranged tubular conductor.