JP2662186B2 - Transmission line electromagnetic interference prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing electromagnetic disturbances such as a screen swing and flickering caused by a magnetic field generated from a power transmission line on an object to be protected, for example, a television receiver.

[0002]

2. Description of the Related Art Generally, 50 H
AC current of z or 60 Hz is several hundred to several thousand
Ampere (A) flows, and a magnetic field corresponding to the amperage is generated. This generated magnetic field propagates through the space, either directly or
Electromagnetic interference occurs by invading from an antenna, a power supply, or the like, affecting the television receiver, and causing the screen to swing or flicker.

[0003] Regarding the technology for preventing the above-mentioned electromagnetic interference,
6 and 7 are proposed (for reference, IEEE Transaction on Power Delivery. Vol.8. No.1.
January 1993. reference). In this technology, a plan view is shown in FIG. 6 and a front view is shown in FIG. 7, between the three-phase transmission line a and the ground b (within the line width) and in parallel with the ground b. Two shielded wires c are laid across the transmission line a in plan view, and both ends of the shielded line c are connected to each other to form a loop d. It is intended to eliminate the influence of the generated magnetic field. Here, e is an overhead ground wire, f is a support column, and g is the ground.

[0004]

However, in the above-mentioned prior art, the loop d is installed within the line width of the transmission line a, and the magnetic field from the transmission line a is strong, and the loop d
Therefore, since the influence of the magnetic field cannot be eliminated unless a strong shielding magnetic field is necessarily generated, the loop d requires a large current of several tens to several hundreds of amperes. Therefore, in order to allow such a large current to flow, the cost of facilities and construction such as large-sized electric wires, series capacitors, and transformers (for forced current) is large, and the power loss required to flow the large current through the loop is large. Is large, so that, for example, a cost of as much as 10% of the construction cost of a transmission line is required, which is uneconomical.

Further, in order to achieve a shielding reduction of at most several tens of percent, the number of shielded wires must be increased and another one wire must be added to perform forced three-phase energization, which is too costly. There is a point. Further, since the loop d is installed within the line width of the transmission line a, the loop d can effectively work only in a magnetic field generated in the transmission line a in a vertical direction toward the ground. However, as shown by the dashed line in FIG. 7, the magnetic field is also spread in the horizontal direction.
There is a problem that it is difficult to think that it can be effectively removed.
In addition, since the house exists at a position separated in the horizontal direction of the transmission line, there is a strong demand for an effective technique for removing electromagnetic interference to the house.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and it is possible to reliably prevent electromagnetic interference occurring in an object to be protected and to reduce the cost of equipment and the power loss of power transmission lines. It is an object to provide an electromagnetic interference prevention device.

[0007]

The present invention has the following arrangement to solve the above-mentioned problems. The invention according to claim 1 is an apparatus for preventing electromagnetic interference generated in a protection target object due to a magnetic field generated from a power transmission line, wherein the device is horizontally erected from the power transmission line and erected at a position close to the protection target object. Multiple distribution
A conductive support member, a ground wire was stretched between the upper ends of at least a pair of power distribution supporting member, a buried wire which is buried in the ground parallel to the ground wire, and the end portions of the ground wire By connecting both ends of the underground buried electric wire, a ground connection line forming a loop including the overhead ground wire and the buried electric wire, and a magnetic field for canceling the generated magnetic field of the transmission line affecting the protection target from the loop. A current supply unit for causing a current to flow through the loop so as to generate the electromagnetic wave.

According to a second aspect of the present invention, there is provided an apparatus for preventing electromagnetic interference generated in a protection target object by an influence of a magnetic field generated from a transmission line, wherein the device is horizontally separated from the transmission line and stands at a position around the protection target object. A plurality of power distribution support members
An aerial ground stretched between the upper ends of the power distribution support members and forming a loop surrounding the protection target body in plan view.
Lines and, electromagnetic interference of the transmission line, characterized in that a said protective current supply unit for a magnetic field for canceling the magnetic field generated by the transmission line affecting the subject flow a current to said loop so as to generate the loop It is a prevention device.

According to a third aspect of the present invention, there is provided the transmission line according to the first or second aspect, wherein a plurality of loops are provided, and each of the turns is connected to at least one of parallel and series. It is an electromagnetic interference prevention device.

According to a fourth aspect of the present invention, there is provided the electromagnetic transmission line according to any one of the first to third aspects, wherein a series capacitor for canceling the reactance of the loop is connected to the loop. It is a failure prevention device.

According to a fifth aspect of the present invention, the loop is inclined at an optimum angle for most effectively canceling a composite generated magnetic field of the transmission line affecting the object to be protected. An electromagnetic interference prevention device for a transmission line according to one aspect.

[0012]

The inventor of the present invention does not provide a shielded line within the line width of a transmission line as in the prior art, but provides a means for preventing electromagnetic interference on the side of a house that needs to be protected from the electromagnetic interference. I considered what to take. Usually, a distribution line is erected along a house such as a private house, and an overhead ground wire is stretched over a power pole supporting the distribution line at a position higher than the roof of the house. Therefore, the inventors devised to use this overhead ground wire as a shielding wire, formed a loop between the overhead ground wire and the underground line, and made the present invention to prevent electromagnetic interference with a current flowing through this loop. It is.

According to the first aspect of the present invention, there is provided a multi-unit, which is horizontally separated from the power transmission line and erected at a position close to the object to be protected.
While using a number of power distribution support members, at least one pair
That stretched the ground wire between the upper end of the distribution support member
Use In addition, buried electric wires will be buried underground in parallel with the overhead ground wire . In addition, both ends of the overhead ground wire and both ends of the underground buried electric wire are connected by a ground connection line to form a loop including the overhead ground wire and the buried electric wire. Then, a current is caused to flow through the loop so that a magnetic field for canceling the transmission line generated magnetic field affecting the protection target is generated from the loop, so that the electromagnetic interference of the protection target can be reliably eliminated.

As the buried electric wire, a bare electric wire or a covered electric wire can be used, and a shielding layer of an existing underground power cable can also be used. Also, if the loops are connected in parallel, the current capacity can be increased and a large amount of current can flow to generate a strong canceling magnetic field.If the loops are connected in series, the canceling magnetic field can be increased with the same amperage. Can be.

Further, if a loop surrounding the object to be held in a plan view is formed, the generated magnetic field in the vertical direction can be effectively canceled.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory view of an electromagnetic interference prevention device for a transmission line according to a first embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a three-phase two-line transmission line. The electromagnetic interference prevention device according to the first embodiment includes a support pole 14 that is a power pole of a general customer distribution line that is horizontally erected from the power transmission line 10 and that is erected near a house 12 to be protected. Support pillar 1
An electric wire (for example, an overhead ground wire of a distribution line) 16 extending between upper ends of the electric wires 4, an embedded electric wire 18 made of an underground cable embedded in the ground in parallel with the electric wire 16, and both ends of the electric wire 16 16a, 16a and both ends 18 of buried electric wire 18 underground
a, 18a to form a loop (closed loop) 20 including the electric wire 16 and the buried electric wire 18, and the transmission line 1 affecting the protected house 12.
And a current supply unit 22 for supplying a current to the loop 20 so that a magnetic field for canceling the generated magnetic field of 0 is generated from the loop 20. In FIG. 1, reference numeral 10g denotes an overhead ground wire of the transmission line 10.

The support column 14 is not limited to a power column, and may be a new column or another type of existing column. Electric wire 16
Is not limited to one that is stretched over a pair of support pillars, that is, two support pillars, and may be one that stretches across another support pillar in the middle. The electric wire 16 may be an overhead ground wire of an existing distribution line, or may be newly extended if there is no existing one. The buried electric wire 18 may use a bare electric wire or a covered electric wire, or a shielding layer of an existing underground power cable, for example.

The number of turns of the loop 20 is not limited to one as shown by a solid line in FIG. 2, but may be a plurality of turns as shown by a two-dot chain line. Alternatively, they may be connected in series. When connected in parallel, the current capacity can be increased, and when connected in series, the number of ampere-turns can be increased as compared with the case of a single turn with the same current. The loop 20 has a reactance, and a series capacitor 24 can be connected as shown by a broken line in FIG. 2 to cancel the reactance.
In addition, the current supply unit 22 supplies an optimal current (hereinafter referred to as a shielding current) to the loop 20 for removing the influence of the magnetic field on the house 12.

In the above-mentioned magnetic disturbance prevention device, for example, as shown in FIG. 2, a loop-shaped detection coil 26 for detecting the strength of a magnetic field is placed close to the loop 20 separately from the loop 20. The detection coil 26 detects the strength of the composite magnetic field of the three-phase power transmission line 10, and a shield current for generating a magnetic field that optimally cancels the magnetic field according to the detected strength is supplied to the loop 20. Shed. Thereby, the transmission line 1
It is possible to prevent the generated magnetic field of 0 from affecting the house 12.

Since an electromotive force is generated in the loop 20 by the magnetic field, instead of the detection coil 26 shown in FIG.
As shown in FIG. 3, the voltage detector 30 and the current supplier 22 are connected to the loop 20 to detect a phase voltage generated in the loop 20 by the magnetic field, amplify the detected voltage, and optimize the current for the loop 20. , The magnetic field can be made zero or close to zero. In this case, first, the voltage detector 30 detects the phase voltage of the loop 20. The detected phase voltage is amplified and input to the current supply unit 22, and a shielding current is supplied from the current supply unit 22 so as to optimally cancel the detection voltage.

The loop 20 is not limited to being substantially perpendicular to the ground as shown in FIG. 1, but the generated magnetic field (composite generated magnetic field, etc.) is optimally removed according to the generated magnetic field of the transmission line 10. The loop 20 can be inclined at an angle that can be obtained. As shown in FIG. 4, for example, in the case of three-phase (R, S, T) transmission lines 10 a, 10 b, and 10 c, three loops 20 a to 20 c having different inclinations are provided to each phase of the transmission line 10. On the other hand, it is possible to optimally remove the influence of the generated magnetic field.

Next, a second embodiment will be described. In the second embodiment, as shown in FIG. 5, a transmission line (three phases of R, S, T) 1
0a, 10b, and 10c, the house 12 to be protected is erected along the periphery of the residential area 32 where one or more houses are located (that is, the house 12).
Support pillars 14 erected around the periphery of each support pillar 1
4 includes an electric wire 36 which is stretched across the upper end portions and forms a loop 34 surrounding one or more houses 12 in the living quarters 32 in plan view, and the current supply unit 22. . The same parts as those in the first embodiment are denoted by the same reference numerals.

A road 38 is provided around the residential area 32, and a support pillar 14 is provided upright at or near the boundary between the road 38 and the residential area 32. The loop 34 can be laid in parallel with the ground, and generates a canceling magnetic field in a direction corresponding to the composite magnetic field of each of the three phases R, S, and T of the transmission line 10 (10a, 10b, 10c). It is preferable to tilt at each optimal degree. The loop 3
4, a current is supplied from the current supply unit 22 to cancel the generated magnetic field. In particular, it is effective for canceling the magnetic field along the vertical direction, and the magnetic field does not affect the house 12 in the living quarters 32. In the second embodiment, a plurality of turns 34 can be provided or a series capacitor can be provided as in the first embodiment.

In each of the above-described embodiments, a house is exemplified as the object to be protected. However, the object to be protected is not limited to this. Can be a body.

[0025]

As described above, according to the present invention, it is possible to reliably prevent electromagnetic interference that occurs in a protected object. At the same time, using the overhead ground wire and power pole of the existing distribution line, the effect of the magnetic field can be removed on the side of the protected object instead of the line width of the transmission line, so the equipment cost is low and the shielding current is low. Since the power consumption is small, the power loss is small. Therefore, the cost is significantly reduced as compared with the related art.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an electromagnetic interference prevention device according to a first embodiment of the present invention.

FIG. 2 is a detailed explanatory diagram of a loop and a current supply unit in FIG. 1;

FIG. 3 is a detailed explanatory diagram of another example of a loop and a current supply unit.

FIG. 4 is an explanatory diagram of an example of a loop inclination.

FIG. 5 is an explanatory diagram of an electromagnetic interference prevention device according to a second embodiment of the present invention.

FIG. 6 is a plan view of an example of a conventional electromagnetic interference removal technique.

FIG. 7 is also a front view.

[Explanation of symbols]

10 (10a, 10b, 10c) transmission line (three-phase (R,
S, T) Transmission line) 12 House 14 Support column 16 Electric wire 18 Buried electric wire 20, 34 Loop 21 Ground connection line 22 Current supply unit 24 Series capacitor 26 Detection coil 30 Voltage detector 32 Living area

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-180771 (JP, A) JP-A-4-122214 (JP, U) JP-B-38-8684 (JP, B1) JP-B-38- 10767 (JP, B1)

Claims (5)

(57) [Claims] 1. An apparatus for preventing electromagnetic interference generated in a protection target object due to a magnetic field generated from a transmission line, comprising: a plurality of vertically extending units which are horizontally separated from the transmission line and close to the protection target unit; and distribution supporting member, a ground wire was stretched between the upper ends of at least a pair of power distribution supporting member, a buried wire which is buried in the ground parallel to the ground wire, and the end portions of the ground wire A ground connection wire that connects both ends of an underground buried electric wire to form a loop including an overhead ground wire and an buried electric wire, and a magnetic field for canceling a magnetic field generated by a transmission line affecting the protection target from the loop. And a current supply unit for causing a current to flow through the loop so as to generate the electromagnetic wave. 2. An apparatus for preventing electromagnetic interference generated in a body to be protected under the influence of a magnetic field generated from a power transmission line, comprising: a plurality of antennas horizontally separated from the power transmission line and erected at positions around the body to be protected; A power distribution support member, an imaginary loop extending between upper end portions of the power distribution support members and forming a loop surrounding the protection target body in plan view.
A ground wire, and a current supply unit that supplies a current to the loop so as to generate a magnetic field for canceling a magnetic field generated by the transmission line that affects the protection target body. Failure prevention device. 3. The apparatus according to claim 1, wherein a plurality of loops are provided, and each of the turns is connected to at least one of parallel and series. 4. The transmission line electromagnetic interference prevention device according to claim 1, wherein a series capacitor for canceling the reactance of the loop is connected to the loop. 5. The method according to claim 1, wherein the loop is tilted at an optimum angle for most effectively canceling a combined generated magnetic field of the transmission line affecting the object to be protected. Transmission line electromagnetic interference prevention device.