JP2764008B2 - Lightning protection method using lightning transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning protection method using a lightning protection transformer for various information systems including semiconductors. The present invention relates to various types of radio relay stations and facilities such as air traffic signposts and the like that are likely to receive lightning strikes, as well as to lightning protection methods including distribution lines that supply power to them.

[0002]

2. Description of the Related Art Conventionally, as a measure against lightning of this type of load equipment, one intermediate electrostatic shield is provided between an input power supply line connected to the load equipment and the load equipment, between an input winding and an output winding. A lightning-resistant transformer having only a board is provided, the outer case of the lightning-resistant transformer and the ground of the intermediate electrostatic shield are connected to the ground of the lightning arrester connected to the input power line, and further connected to the main ground of the load equipment. The single point grounding method of lightning protection was adopted.

In the lightning protection method described above, a lightning surge connected to the input power supply line and a lightning arrester connected to the input power supply line and an intermediate electrostatic shield plate provide a certain lightning protection effect. The grounding wire of the lightning arrester provided on the wire and the grounding of the load equipment and the like are still electrically connected by the connecting grounding wire, so there are still various difficulties. In particular, when a lightning strike strikes the antenna tower on the load equipment side, the potential of the main ground of the load equipment rises and not only destroys the lightning arrester by reverse discharge, but also causes a large shunt component of the lightning current to be input to the input power supply. Into the distribution line on the side, causing a large distribution line accident. Also, it was difficult for the load equipment to equalize all equipment under high potential against a large lightning surge, causing various damages.

[0004] In order to prevent the above-mentioned adverse effects, there are proposals in Japanese Patent Application Laid-Open Nos. 57-149713 and 3-86017. The proposed lightning protection measures include an intermediate electrostatic shielding plate between the input winding and the output winding in the input power supply line connected to the load equipment, and furthermore, a connection between the intermediate electrostatic shielding plate and the input winding. A lightning proof transformer having an electrostatic shield plate insulated on each of the input winding and the intermediate electrostatic shield plate so as to enclose the input winding, and an electrostatic shield plate on the input winding side of the lightning proof transformer, A configuration in which the electrostatic shielding plate and the ground of the load equipment are separately grounded (see JP-A-57-149713), or an output winding is further provided between the intermediate electrostatic shielding plate and the output winding in addition to this configuration. An electrostatic shielding plate is provided so as to wrap and is insulated from each of the output winding and the intermediate electrostatic shielding plate. Configuration that is separate from grounding of shield plate and load equipment or connected to ground of load equipment 149713, JP-A-3-86017).

[0005] The lightning protection method having the above-described structure having the input-winding-side electrostatic shield plate and the intermediate electrostatic shield plate is applied when the probability of surge penetration is smaller than the antenna of the load equipment or the main ground. With respect to a lightning surge that enters from the input power supply line side, an electrostatic shield plate is provided on the input winding side, so that the shift to the load side is greatly attenuated, and the load equipment is protected.

Further, in the lightning protection method of the latter configuration, in addition to the former configuration, an electrostatic shielding plate is also provided on the output winding side, and the ground is separated from the ground of the other electrostatic shielding plates.
Alternatively, as described in JP-A-3-86017, the circuit from the output winding to the load equipment can be formed to have the same local electric potential in accordance with the electric potential because the circuit is connected to the main ground of the load equipment. The lightning transformer completely insulates the input power line going out to the outside, and the action of the electrostatic shielding plate can prevent the failure caused by the transition of the surge, and an excellent lightning protection method can be established. It has been widely adopted and has produced outstanding effects.

[0007] In the above lightning proof method, it is essential to be able to protect the equipment in the station including the semiconductor equipment and the distribution line for supplying power thereto when the lightning strikes directly on the antenna tower of the radio relay station. There are conditions. That is, in general, a lightning proof transformer is generally installed outdoors in or near a place. Since the distance between the grounding position of the intermediate electrostatic shielding plate provided near the installation location and the main ground is short, the intermediate electrostatic shielding is generally used. The grounding of the board can be shared with the main grounding in the same way as the grounding of the electrostatic shielding plate on the output winding side, and additional grounding work can be omitted, but in order to obtain an excellent lightning protection effect The grounding of the electrostatic shielding plate on the input winding side is several to the main grounding pole.
It needs to be separated by about 30m, so additional grounding work is required.

[0008]

The above lightning protection method can be applied to all semiconductor application systems. However, as described above, the grounding of the electrostatic shielding plate on the input winding side is different from the main grounding of the load equipment. Separate grounding poles must be provided for grounding, so existing radio relay stations installed on the top of the mountain, air traffic sign lights for power lines, etc., as well as these, are being rapidly installed in many places these days. In the case of mobile radio relay stations on the summit or flat ground, the site area is often limited due to the location conditions, leasehold rights, etc.At the summit, there is a bedrock layer close to the surface, In addition, there are many underground structures such as road pavement and water and gas, and there are also issues such as leasehold rights.Therefore, it is necessary to provide an independent and separate ground electrode in addition to the main ground electrode of load equipment. Very difficult in many cases It came.

Therefore, the present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to reduce the number of grounding poles of electrostatic shielding plates on the input winding side and the output winding side without increasing the number of grounding poles. It is an object of the present invention to provide a lightning protection method that can enjoy the excellent effect of the lightning transformer and can further improve the lightning protection effect of the lightning transformer by one step to prevent even a failure in a noise region.

[0010]

In order to achieve the above object, the invention according to claim 1 of the present invention provides an input winding and an output winding between an input power supply line connected to a load facility and the load facility. Each of the wires is provided with a lightning proof transformer having an independent electrostatic shielding plate which is insulated from each other, and the electrostatic shielding plate on the output winding side of the lightning proof transformer is connected to the main ground of the load equipment, while the input winding side Is connected to the zero potential line of the input power supply line.

According to a second aspect of the present invention, there is provided an independent electrostatic shield plate which is insulated from an input power supply line connected to a load equipment and an output winding, respectively, between an input power supply line and the load equipment. A lightning proof transformer having a lightning proof transformer is provided, and the electrostatic shielding plate on the output winding side of the lightning proof transformer is connected to the main ground of the load equipment, and the electrostatic shielding plate on the input winding side is connected to any of the input power lines. In addition to connecting to one of these lines, an input power supply line is provided with a line arrester.

According to a third aspect of the present invention, there is provided a lightning proofing method using the lightning proofing transformer according to the first or second aspect of the present invention. An insulated intermediate electrostatic shield is provided, and this intermediate electrostatic shield is connected to the electrostatic shield on the output winding side or directly to the main ground of the load equipment.

[0013]

According to the present invention, there is provided a lightning proof transformer having an independent electrostatic shielding plate insulated from each other at least in each of the windings between an input winding and an output winding. The basic principle is to connect the electrostatic shield plate on the input winding side to any one of the input power supply lines, so that the grounding of the electrostatic shield plate on the input winding side is independent grounding. It can work the same as connecting to the pole. That is,
In general, except for special cases, in the case of a radio relay station, high-voltage power is sent to the drop pole, which is the responsibility demarcation point, or the telephone pole in front of it, and converted to low voltage by a pole transformer installed there. Power is being supplied. Usually, the pole transformer is of the second type ground, and one of the input power supply lines is a line of zero potential. Therefore, by connecting a lightning arrestor directly or indirectly to this line and connecting the electrostatic shielding plate on the input winding side indirectly to the input winding side, the electrostatic shielding plate on the input winding side can be connected to an independent grounding electrode. Can be made to work in the same way as connected to the power supply, and without the need for additional grounding of the electrostatic shielding plate on the input winding side, the load equipment can be installed from the distribution line side by the outstanding effect of the lightning proof transformer. Can be prevented from being damaged by lightning.

Although the ground current of lightning becomes smaller as it gets farther, it flows from the surface over a distance of several kilometers toward the lightning strike point through a relatively shallow place in the ground. Therefore, considering that the zero potential point is beyond that, the potential difference between the mesh installation installed on the full site of the radio relay station and the type 2 grounding of the pole transformer installed at intervals of within several tens of meters Is not as large as normally assumed, so even if this type 2 grounded zero-potential line is connected directly or indirectly through a lightning arrestor to the electrostatic shielding plate on the input winding side The insulation strength between the input shield-side electrostatic shield plate and the other electrostatic shield plate connected to the main ground of the relay station is a finite value that can be used practically. It can be used as a substitute for the ground electrode of the shielding plate.

An intermediate electrostatic shielding plate is provided between the input winding and the output side electrostatic shielding plate, and the grounding of the intermediate electrostatic shielding plate is shared with the grounding of the output winding side electrostatic shielding plate. , A more effective lightning resistance effect can be obtained.

The lightning proof transformer applied to the present invention can be applied to a lightning proof transformer having the same structure as that of the above-mentioned prior art, and can be improved to be most suitable for the lightning proof method of the present invention. Have the same function.
In addition to the important features that do not require additional grounding work according to the present invention, the reason for providing a far superior lightning resistance effect is as follows.

According to the conventional method, from the low voltage winding of the pole transformer on the distribution line to the input winding of the lightning proof transformer to the electrostatic shielding plate thereof, the conventional method uses the electrostatic shielding plate on the input winding side. The position of the grounding point is different from the type 2 grounding point on the pole transformer, and there is a potential difference between the grounding arrester of the lightning proof transformer and the type 2 grounding point due to the potential difference between them. There was a possibility that the diverted flow would flow, causing various troubles. In the present invention, from the outer casing of the pole transformer, from the low voltage winding to the input winding of the lightning proof transformer and the electrostatic shielding plate thereof, the second step is performed.
There is an advantage that the same potential at the seed ground point and the single-point ground are achieved.

Compared to the seemingly insignificant difference, the fact that a great lightning protection effect and a noise interference prevention effect can be expected is based on the invention proposed in JP-A-57-149713. This is to improve the essence of the concept of the lightning protection method up to the invention. That is, JP-A-57-149713
At the time when the invention of the publication was proposed, the main point was that the lightning surge came from a power source, and the main purpose was to be able to exponentially reduce the rate of lightning surge transfer to the load side exponentially with a multilayer shield. After that, in order to eliminate damage even at radio relay stations that are likely to be directly hit by lightning, the volume from the output winding of the lightning proof transformer to the load equipment was minimized as specified in JP-A-3-86017. Developed a local equipotentialization system wrapped in a Faraday cage, thereby eliminating many lightning stations in winter lightning areas, especially in winter, where direct lightning strikes about 10 times a year, as well as lightning damage to distribution lines that supply them. There are outstanding effects. In recent years, the rapid development of the information-oriented society has led to the use of many semiconductors that are extremely vulnerable to surges, and to eliminate the drawback of requiring at least one additional ground as an essential condition. The invention was developed to complete the lightning proof concept, and the invention described in claim 1 or 2 according to the present invention also fulfills the general role. However, the invention described in claim 3 achieves a near ideal purpose. What you get.

No matter how high the potential of the Faraday cage covered with metal is, the electric field strength inside is zero. However, this can be said after all the metals have been uniformly raised to a high potential. Until then, a sharp strong electric field has been generated inside. Ideally, no current should flow through the cage itself. In addition, if there is a line that enters and exits from the high potential Faraday cage, a current flows out of the line and the effect of the Faraday cage is lost.
To prevent this, it is necessary to insulate the line leading to the outside from the electric system inside the Faraday cage.

The present invention has been made to satisfy the above two conditions. In order to satisfy the first condition, the Faraday cage fixed at the potential of the main ground point of the load equipment was multilayered, and to satisfy the later condition, the potential was fixed at the second type ground point of the pole transformer. A separate Faraday cage connected to the outside is constructed, and both Faraday cages are insulated by a lightning proof transformer.

FIG. 1 illustrates the outline of the above operation. Reference numeral 1 denotes a first Faraday cage constituted by a steel frame of a building. Due to a difference in a lightning current passage distance or the like, especially at a wave front, each part of the Faraday cage is not at the same potential.

Reference numeral 2 denotes a second Faraday cage reaching the intermediate electrostatic shielding plate 7 and the main ground 8, and as shown by a thin line, depends on a metal tube, a duct, a shielding room or the like for accommodating a cable wiring with a sheath. Usually, it is often not necessary to take measures until reaching this thin line portion.

Reference numeral 3 denotes a final third Faraday cage, which is an electrostatic shielding plate 10 on the output winding side of the lightning proof transformer 9, a metal tube,
It consists of a duct and an outer box of load equipment,
4, the electric circuit from the output winding of the lightning proof transformer 9 to the load facility, and the indoor wiring to the electric circuit, are wrapped in a minimum volume to achieve local potential equalization. A load transformer (not shown) often uses a power transformer internally. One of the input terminals 11 is connected to the main ground 8 at the input terminal to reach the output winding of the lightning proof transformer 9. All the main ground up to 8
Stabilize at potential.

Reference numeral 6 denotes a circuit up to the input winding of the lightning proof transformer 9, the low voltage drop wire, and the low voltage winding of the pole transformer 12. The outer casing of the pole transformer 12 is wrapped around the circuit. 13 and, if necessary, a Faraday cage 5 composed of a drop-in wire made of a cable with a sheath and an electrostatic shield plate 14 on the input winding side of the lightning proof transformer 9, together with an electric circuit 6 of a power supply, and a second-type ground 15. As a result, a single point ground fixed to the ground potential at that position is formed.

The electric circuit 4 of the load equipment thus set to the potential of the main ground 8 of the load equipment, the Faraday cage groups 1, 2, 3 surrounding the electric circuit 4 and the input power supply fixed to the electric potential of the second type ground point 15 Circuit 6 and its surrounding Faraday cage 5
The lightning current path is cut off by an insulator between the intermediate electrostatic shielding plate 7 and the input winding side electrostatic shielding plate 14 in the lightning proof transformer 9 therebetween. However, the current shown by 16 mainly flows at the wave front having a high steepness due to the capacitance in the meantime, but this flows through the electrostatic shield plate 14 on the input winding side, the zero potential line of the input power supply line, and It is harmless because it is discharged to the ground through the second type grounding point 15 through the cable sheath. As described above, the current 16 inside the second Faraday cage 2 having only the crest and having a very small crest is caused to flow, so that the same potential inside is slightly collapsed.
A small current flows through the Faraday cage 3. As a result, a current as much as noise may flow from the load circuit to the third Faraday cage 3, but there is a single-wire ground at the power supply input terminal 11 of the load equipment, and most of the ground passes from the main ground through the indoor wiring. Since it is supplied, the current flowing in the semiconductor circuit becomes practically zero.

The reason why one line is grounded at the power supply input terminal 11 of the load equipment is that a transformer is usually used inside the load equipment, and therefore, the output winding of the lightning proof transformer 9 is used. This is to prevent the potential of the indoor wiring reaching the load equipment from becoming unstable and to fix it to the potential of the main ground 8.

Here, if a cable of a long distance is used carelessly to completely enclose an electric circuit, the capacitance between the Faraday cages may be adversely affected, and the Faraday cage portion indicated by thin lines is released. It is often better to do it. Further, when a lightning surge enters from the power line side, not only the power is much smaller, but also the power flows from the electrostatic shielding plate 14 on the input winding side to the main ground 8 as it flows through the capacitance between the shielding plates. Can be protected.

Although FIG. 1 has been described by taking as an example a lightning proof transformer 9 having an intermediate electrostatic shielding plate 7, the intermediate electrostatic shielding plate 7 is omitted and the second Faraday cage 2 is omitted. In this case, an electric current of about this amount flows between the electric circuit 4 of the load equipment and the output-winding-side electrostatic shield plate 10, but it is not sufficient unless the semiconductor is exceptionally weak. Although difficult, some effects can be expected.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is an electrical connection diagram showing an outline of a lightning protection device such as a wireless relay station according to the present invention. Reference numeral 21 denotes a lightning proof transformer, 22 denotes a load facility of a radio relay station, 23 denotes a lightning rod, and 24 denotes a pole transformer.

The lightning proof transformer 21 has an input winding 25 and an output winding 26.
Each of which has an electrostatic shielding plate 27, 28 and an input winding
A lightning arrester 29 is provided between the 25 lines, and is installed in the radio relay station adjacent to the load equipment 22. And the input winding 25
Is connected to an external power supply line 30 from the pole transformer 24, and the output winding 26 is connected to a load facility 22.

The electrostatic shielding plate 27 is connected to the zero-potential line 30a of the pole transformer 24, which is grounded to the second type 31. The electrostatic shielding plate 28 is connected to the main ground 32 together with the load equipment 22 and the output winding 26.

The lightning rod 23 is connected to the main ground 32 including the steel structure of the building of the radio relay station, and is configured to form a Faraday cage 33 including the lightning rod 23 and the steel structure of the building during a lightning strike.

In the figure, reference numeral 34 denotes an imaginary ground wire, 35
Indicates the grounding of the lightning arrester provided on the high voltage side of the pole transformer.

Next, a description will be given of a case where the lightning rod 23 is directly hit by lightning and a case where a lightning surge enters from the power supply side in the above configuration.

When a lightning strike is received by the lightning rod 23, as shown in FIG. 3, the lightning strike current X1 flows from the main ground 32 to the ground through the antenna tower and the steel frame of the building. However, at the wave front, a current indicated by a broken line X2 flows through the capacitance between the two electrostatic shielding plates 27 and 28 due to the potential difference between the two points of the main ground 32 and the second type ground 31. This is the current X3 flowing to the ground from the second type ground 31 through the zero potential line 30a of the incoming power supply and the overhead ground wire 34.
Shunted to the current X4. From the grounding point 35 of the lightning arrester 36, due to the increased potential at that point due to the lightning current, the lightning arrester 36 is reverse-discharged and a current indicated by X5 flows toward the high-voltage distribution line. Since it is a divergent component, it is not damaged.

The insulation strength between the grounding plates of the electrostatic shielding plates 27 and 28 is indicated by a broken line because it is designed to sufficiently withstand the potential difference between the grounding points of the second type grounding 31 and the main grounding 32. X
2, The current of X3, X4 disappears. However, since the potential of the ground of the second type ground 31 is high, the shunt component of the lightning current indicated by the solid line X6 flows to the overhead ground wire 34.

FIG. 4 shows a case in which a lightning surge enters from the power supply side. In this case, almost the same function as that of the conventional grounding method is obtained, and thus, a steep wave of potential change is obtained. Since only the head current flows as indicated by the dashed arrow and passes through a place completely unrelated to the load equipment 22, the load equipment 22 of the radio relay station is not damaged.

In the above embodiment, the lightning transformer is provided with the electrostatic shielding plates 27 and 28 on the input winding 25 and the output winding 26, respectively.
Although the example has been described with reference to FIG. 21, as shown in FIG.
A configuration in which an intermediate electrostatic shielding plate 37 is provided between 28 may be adopted.
In this case, the insulation strength between the electrostatic shielding plates 27 and 28 is further increased, and when the lightning rod 23 is directly hit by lightning, the same operation as described in the paragraph [0025] based on FIG. Therefore, only the current of the wave front having a high steepness mainly flows, but this flows through the electrostatic shielding plate 27 on the side of the input winding 25 and the input power supply line 30.
It is harmless because it is discharged to the ground through the second type grounding point 31 through the zero potential line 30a of FIG. Also, when a lightning surge enters from the power supply side, the paragraph number [003
As described in [7], only the current at the crest where the potential change is steep passes through a place that is completely unrelated to the load equipment 22,
Moreover, the energy is 1 compared with the case of the above embodiment.
Since it is less than two orders of magnitude, the load equipment 22 of the radio relay station is unlikely to be damaged.

In the above-described embodiment, the case of the single-phase two-wire system, in which the line of the second kind is made in advance and the line having the zero potential has been confirmed, has been described. A lightning arrestor (not shown) should be provided between the wires 30a and 30b regardless of the confirmation, and the input winding 25 should be connected to either wire 30a or 30b.
Even if the electrostatic shield plate 27 is connected, the same operation and effect as those of the above embodiment can be obtained, and the damage to the load equipment 22 of the wireless relay station can be prevented.

In the case of a single-phase three-wire system, a three-phase three-wire system, or the like, the electrostatic shielding plate 27 of the input winding 25 is connected to the second-type grounded zero potential line, When the electrostatic shielding plate 27 of the input winding 25 is connected to any one of the input lines without selecting the input line, the same operation and effect as in the above embodiment can be obtained by providing a lightning arrestor between each line. The damage to the load equipment 22 of the radio relay station can be prevented.

[0041]

As described above, according to the lightning proofing method using the lightning proof transformer according to the present invention, the input winding and the output winding can be formed without increasing the grounding of the electrostatic shielding plate on the input winding side. It is possible to use a lightning proof transformer having an independent electrostatic shielding plate insulated from each other in at least each of these windings to prevent damage to lightning of load equipment of various information systems including semiconductors. it can.

In particular, the site area is small, and it is difficult to carry out additional grounding work for lightning protection at a mountaintop or the like.
In addition, by applying to facilities such as various radio relay stations and air traffic signposts for transmission lines that are highly likely to be subjected to lightning strikes, it is possible to economically and effectively load equipment for various information systems including semiconductors in these facilities. Can protect against lightning strikes.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an outline of an operation according to the present invention.

FIG. 2 is an electrical connection diagram showing an outline of a lightning proof device such as a wireless relay station according to the present invention.

FIG. 3 is an explanatory diagram showing a flow of a lightning surge current when a lightning rod is directly hit by a lightning arrester in FIG. 2;

FIG. 4 is an explanatory diagram showing a flow of a lightning surge current when the light enters from the input power supply side in FIG. 2;

FIG. 5 is an electrical connection diagram showing an outline of a lightning proof device such as a wireless relay station according to another embodiment of the present invention.

[Explanation of symbols]

1: First Faraday Cage 2: Second Faraday Cage 3: Third Faraday Cage 4: Electric Circuit 5: Faraday Cage 6: Electric Circuit 7: Intermediate Electrostatic Shield 8, 32: Main Ground 9, 21: Lightning proof transformer 10, 28: Output winding side electrostatic shielding plate 11: Input terminal contact 12: Pole transformer 13: Outer pole of pole transformer 14, 27: Input winding side electrostatic shielding plate 15, 31: Class 2 grounding 16: Current with very small wave tail only at the crest 22: Load facilities at radio relay stations 23: Lightning rod 24: Pole transformer 25: Input winding 26: Output winding 29 : Lightning arrester 30, 30a, 30b: External power line 33: Faraday cage X1: Direct lightning current of lightning X2 to X6: Surge current flow of lightning

Claims (3)

(57) [Claims] 1. A lightning proof transformer having an independent electrostatic shielding plate insulated from each of an input winding and an output winding between an input power supply line connected to the load equipment and the load equipment, wherein the lightning proof transformer is provided. The electrostatic shield plate on the output winding side is connected to the main ground of the load equipment, while the electrostatic shield plate on the input winding side is connected to the zero potential line of the input power line. Lightning protection method. 2. A lightning proof transformer having independent electrostatic shielding plates insulated from each other on an input winding and an output winding between an input power supply line connected to the load equipment and the load equipment, wherein the lightning proof transformer is provided. Connect the electrostatic shield plate on the output winding side to the main ground of the load equipment, connect the electrostatic shield plate on the input winding side to any one of the input power lines, and connect A lightning protection method using a lightning protection transformer equipped with line arresters. 3. A lightning proofing method using a lightning proof transformer according to claim 1 or 2, wherein a mutually insulated intermediate electrostatic shielding plate is provided between each of the electrostatic shielding plates of the input winding and the output winding.
A lightning protection method using a lightning protection transformer in which the intermediate electrostatic shielding plate is connected to the electrostatic shielding plate on the output winding side or directly to the main ground of the load equipment.