JP2974302B2 - Method of suppressing magnetic field around power supply line - 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 suppressing a magnetic field around a power supply line, and more particularly, to a magnetic field generated around a power supply line having parallel forward and return conductors and affecting the direction of electron flow of a cathode ray tube. The present invention relates to a device for suppressing the pressure.

[0002]

2. Description of the Related Art Referring to FIGS. 2 and 3, current is supplied from a power source to a motorized device 5 such as a train by a trolley wire, and the current is returned to the power source via a conductive rail. I have. In this case, the trolley wire becomes the outgoing conductor 1, and the rails parallel thereto become the inward conducting wires 3 and 4, which form a parallel reciprocating power supply line to the conductive device 5. Since the trolley wire has other requirements such as maintaining contact with the pantograph of the train, the feeder wire 2 may be stretched in parallel with the trolley wire. At an arbitrary point P around the parallel reciprocating feeder, the magnetic flux density Bf (vector quantity) of the magnetic field due to the forward current on the forward wires 1 and 2 and the magnetic flux density Br of the magnetic field due to the backward current on the return wires 3 and 4 Flux density B corresponding to the vector sum of
(B = Bf + Br) magnetic field (hereinafter simply referred to as ambient magnetic field)
Occurs.

[0003] A point P is defined as the forward conductors 1 and 2 and the return conductors 3 and 4.
When the distance is sufficiently large, the magnetic field Bf due to the forward current on the forward conductors 1 and 2 and the magnetic field Br due to the backward current on the return conductors 3 and 4 become sufficiently small due to the distance attenuation characteristics of the magnetic field. B is practically negligible. However, when the point P in the house 6 is close to the parallel reciprocating feeder, the surrounding magnetic field B has a finite value that cannot be ignored, and the point P
For example, when an electron flow utilizing device 7 such as a cathode ray tube is present, the electron flow inside the device 7 is undesirably deflected by the surrounding magnetic field B, causing magnetic interference such as distortion, color shift and other disturbances in the image. Have been experienced.

Conventionally, in order to suppress such magnetic interference of the surrounding magnetic field B, the electron flow utilization device 7 is covered with a magnetic shielding material, or the outward conductor 2 corresponding to the feeder is simply placed on the opposite side of the device 7. Attempts have been made to relocate or cover the outward conductor 2 equivalent to a feeder wire with a magnetic shielding material.

[0005]

However, in the conventional method of covering the electronic flow utilizing device 7 with a magnetic shielding material, the handling of the device 7 becomes inconvenient, the commercial design of the device itself is impaired, and a strong ambient magnetic field is used. When B is present, there is a problem that a large amount of magnetic shielding material is required and becomes heavy and inconvenient to move. The method of simply relocating the outbound conductor 2 corresponding to the feeder wire or covering it with a magnetic shielding material takes into account the effects of the current on the rails corresponding to the trolley wire 1 corresponding to the other outbound conductor 1 and the inbound conductors 3 and 4. Therefore, no sufficient effect of suppressing magnetic interference could be obtained.

Accordingly, it is an object of the present invention to provide a method for suppressing magnetic interference due to parallel conductor current at an arbitrary position around a reciprocating feeder including three or more parallel conductors.

[0007]

Referring to the embodiment of Figure 1 and 5 SUMMARY OF THE INVENTION The ambient magnetic field suppression method of the power supply line of the present invention, feeding circuit
Two or more outbound conductors 1 and 2 including inbound wire 2 and outbound conductor 3
You to a reciprocating feed line, including Ranaru three or more of the conductors 1, 2, 3
Kicking defines each conductor current, set the conductor arrangement in the feed line且
The magnetic flux density B around the feeder line due to each of the above determined conductor currents
(= Bf + Br) (FIG. 3) is calculated, and the calculation result of the magnetic flux density at a predetermined position in the surrounding is the magnetic flux at the predetermined position.
Determines whether less than the allowable value of the density, the lead distribution by results <br/> changes the set position of the wire 2 come when whether the determination
Reset and the recalculation of the distribution of the magnetic flux density B and the determination
And the position of the feeder wire 2 is changed to the magnetic flux density at the predetermined position.
This is determined at a position where B is equal to or less than the allowable value . In addition, the feeder position determining device of the present invention
Including three or more, consisting of two or more outbound routes and return routes
Of each conductor in the reciprocating feeder including the conductors 1, 2, and 3
Means 10 for determining the flow, setting the position of the conductor in the feeder and
Selection means 11 of the wire arrangement to be changed, set by the selection means
The current determined by the above-mentioned
The distribution of magnetic flux density B (= Bf + Br) around the feed line
Calculating means 12, the magnetic flux density B at a predetermined position in the surroundings
Environmental condition input means 13 for giving an allowable value of
The magnetic flux density at the predetermined position obtained in
Means 14 for determining whether or not the
When the judgment result is negative, the selection means 11
Change and recalculation of the distribution of magnetic flux density B by the calculation means 12
And the above determination is repeated to determine the position of the feeder line 2.
A position where the magnetic flux density B at the predetermined position is equal to or less than the allowable value.
Is determined.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Outgoing conductors 1, 2 and inward conductors 3, 4
The operation will be described with reference to the embodiment of FIGS. 1 to 6 having the four parallel conductors. However, a similar operation can be performed in the case of a reciprocating feed line having three or five or more parallel conductors.

In step 41 of FIG. 4, the number of fixed conductors is determined by, for example , four conductors 1, 2, 3, 4 as in the embodiment of FIG.
It is determined as a book, and the number of conductive wires whose position can be adjusted is determined as one of the conductive wires 2, for example. However, the number of conductors is not limited to four,
Three outgoing conductors 1, 2 and 3
Therefore, the method for suppressing the magnetic field around the feeder described below
The same applies to the case where the number is three. In step 42, the value of the current flowing through each of the conductors 1, 2, 3, and 4 is set by the number of cases necessary for the study. For example, before constructing equipment
A base load current flowing continuously for a long time, a peak current flowing only for a short time, an intermediate current thereof, and the like are determined. Alternatively, the current value flowing through each of the conductors 1, 2, 3, and 4 is measured and determined after the construction of the equipment. The determination of this current value determines the conductor current
This is done by means 10 . The geometry of the fixed conductors 3,4 in step 43 is fixed as shown in Figure 5, for example. Next, in step 44 , the geometrical arrangement of the electric wire, that is, the movable conductor 2 is set as shown in FIG. 5, for example. The setting of the position of the feeder <br/> is the selection of the conductor arrangement for setting and changing the position of the feeder
This is performed by means 11.

Thereafter, at step 45, each of the wires 1, 2,.
The set of current values flowing through 3, 4 or the current case is represented by I ₁ + I ₂
It is assumed that + I ₃ + I ₄ = 0. For example, in the case of FIG. 5, the currents of the forward conductors 1 and 2 are each 900 A based on the measured values in the actual equipment, all the forward currents are the return currents, and are equally divided into the two return conductors 3 and 4 to 900 A each. It is going to be. In step 46, four wires 1, 2,.
The calculation means 12 calculates the magnetic flux density distribution at an arbitrary point around the reciprocating feed line due to the currents on the lines 3 and 4. This operation assumes that conductors 1, 2, 3, and 4 are all parallel, infinitely long for convenience of calculation, and the following Bio-Savart if the surroundings of the reciprocating feed line are in uniform air: It is convenient to follow the rule.

[0011]

(Equation 1)

Here, B is the magnetic flux density at a certain point due to the current in all the conductors, B _i is the magnetic flux density due to the current in the i-th conductor, I _i
Is the current on the ith wire, r is the distance between ds and the point,
ds is a minute portion of the conductor through which the current I _i flows, μ is the magnetic permeability of air or other medium, B, r and ds are vector quantities, μ
And r ³ are scalar quantities, and I _i is a vector quantity of positive or negative value. If the circumference of the reciprocating feed line is not uniform and there is a magnetic material, for example, or if the conductor cannot be assumed to be an infinite straight line and is a curve, for example, Maxwell's law shown in the magnetic flux density calculating means 12 in FIG. And the finite element method or the boundary element method.

On the other hand, the environment condition setting means 13 sets, for example, the position of the electron flow utilization device 7 and the allowable magnetic flux density.
The allowable magnetic flux density is temporarily set to 30 μT for convenience of explanation.

The distribution of the magnetic flux density calculated by the calculating means 12 is displayed as shown in FIG. 5, for example, at the drawing stage of the determining means 14 in FIG. If the position of the electron flow utilization device 7 set by the environmental condition setting means 13 is written in the magnetic flux density distribution diagram thus created as shown in FIG. 5, the magnetic flux density B of the environment where the device 7 is placed is, for example, Obtained as about 48 μT.
The determining means 14 compares the magnetic flux density B at the predetermined position obtained in this way with the allowable magnetic flux density set by the setting means 13, for example, 30 μT, and in this case, on the reciprocating power supply line at the given position of the electron flow utilization device 7. It is determined that the magnetic flux density B due to the current is too large.

For all of the different current value cases set in step 42, the end of the judgment by the judging means 14 is confirmed in step 47, and thereafter, the process returns to step 44 and shown in FIG.
The position of the feeder wire 2 is changed by the conductor arrangement selecting means 11.
As shown in FIG. 6, approaching the rails, an attempt is made to suppress the effect of the current on the return wires 3 and 4 by the current on the feeder wire 2 on the outward route. Thereafter, when the processing of steps 45 to 46 in FIG. 4 is repeated for the case of 900 A, the magnetic flux density distribution shown in FIG. 6 is obtained, and the magnetic flux density B of the environment where the device 7 is placed can be reduced to about 25 μT, for example, by approximately half. Turns out. Furthermore, the allowable magnetic flux density set in this example could be suppressed to 30 μT or less.

In the case where the allowable magnetic flux density is lower, FIG.
From the comparison between FIG. 6 and FIG. 6, the same simulation can be repeated with the position of the outward conductor 2 set further below.

Even when the number of electric wires of the reciprocating power supply line is three or five or more, the method of the calculating means 12 of FIG. 1 uses the method of the calculating means 12 as shown in FIG. The method described above can be applied substantially as it is.
When the number of conductors of the reciprocating feeder is two, the relative positions between the two conductors are concentrated only in the perspective relationship, and are not subject to suppression according to the present invention.

Accordingly, the object of the present invention is to provide a " method of suppressing magnetic interference caused by a parallel conductor current at an arbitrary position around a reciprocating feeder line including three or more parallel conductors".

[0019]

According to one embodiment of the present invention, the magnetic flux density B at an arbitrary position P around a reciprocating feeder line including three or more parallel conductors is made substantially zero or less than a required value. it can. Referring to FIG. 7, one parallel conductor whose installation position can be adjusted is selected, for example, as the outward conductor 2, and the magnetic flux density B at the position P due to the current on the other conductor in the reciprocating feeder, for example, the conductors 1, 3, 4 (1, 3, 4) is obtained by the magnetic flux density calculation means 12. If the magnetic flux density B (2) having the same magnitude and the opposite direction as B (1,3,4) can be generated by the current on the outward conducting wire 2, the magnetic flux density B at the position P becomes zero. Such a magnetic flux density B (2)
Is generated in this case, the conductive wire 2 can be calculated in this case.
It is on a line orthogonal to (1, 3, 4), that is, on a line that forms an angle θ with the horizontal plane H. The distance S from the position P to the conductor 2
And the direction and magnitude of the current on the conductor 2 are determined by the magnitude of B (1, 3, 4). The outgoing current flows through the conductors 1 and 2,
When a reverse current flows through the conductors 3 and 4, it is theoretically possible to flow a current having a direction and magnitude satisfying the above conditions through the conductor 2.

In particular, the conductors 1, 3, 4 fixed at predetermined positions
Referring to FIG. 9, a description will be given of a method of positioning the conductor 2 for suppressing the surrounding magnetic field in a case where it is assumed that all the conductors 2 whose positions can be adjusted are parallel and infinitely long. In block 901, the current values of the conductors 1, 2, 3, 4 are appropriately set according to the load conditions, and the positions of the fixed conductors 1, 3, 4 are
Set as coordinate value in 2. The magnetic flux density B (tesla) generated at the point P by the current I (ampere) on one infinitely long straight conductor has a magnitude represented by the following equation (2), and its direction is given by the right-handed screw rule. Can be Note that r (meter) is the distance between the current I and the point P.

[0021]

(2) B = (μ / 2π) (I / r) (2)

The magnetic flux density B (1,3,4) generated by the current on the three conductors 1,3,4 is, as shown in block 903, the vector of the magnetic flux density of equation (2) by the current on each conductor. Required as a sum. The position of the conductor 2 for suppressing the surrounding magnetic field is determined by the point P determined by the current I ₂ on the conductor 2 determined earlier.
May be selected so that the magnetic flux density at-is (-B (1, 3, 4)) (see FIG. 7). For this purpose, a straight line perpendicular to the vector B (1, 3, 4) is drawn at the point P, and the conducting wire 2 is arranged on the straight line at a position separated from the position P by a distance r ′ given by the following equation. Good (see block 904).

[0023]

R ′ = (μ / 2π) (I ₂ / −B (1,3,4)) (3)

Here, μ is the magnetic permeability of the medium, which can be substituted for air by the vacuum magnetic permeability μ ₀ = 4π × 10 ⁻⁷ , and I ₂ is the current on the conductor 2. Although there are two solutions of equation (3), an appropriate solution is selected according to the right-hand screw rule and the required magnetic flux direction at the position P.

FIG. 8A shows the result of selecting the position of the conductive wire 2 and the current thereabove and calculating the distribution of the surrounding magnetic flux density B. In FIG. 8B which shows a bird's-eye view of the magnetic flux distribution on a horizontal line passing through the position P in FIG. 8A, the horizontal axis is a rail on a horizontal plane vertically separated by a distance h from the conductors 3, 4 which are rails in this case. The vertical axis indicates the magnetic flux density B, and the depth indicates the distance in the rail direction. As is clear from this figure, on a horizontal plane passing through the position P, there is a linear region L where the magnetic flux density B becomes substantially zero. Further, the magnetic flux density is Ba along the linear region L.
The groove portion 15 having the following magnetic flux density distribution with a low magnetic flux density can be generated with a finite width W. The magnetic flux density B can be kept very low inside the groove portion 15.

[0026]

As described in detail above, the method for suppressing the surrounding magnetic field of the parallel reciprocating feeder according to the present invention suppresses the surrounding magnetic flux density depending on the installation position of the conducting wire, and therefore has the following remarkable effects.

(1) The magnetic flux density of the magnetic field around the parallel reciprocating feeder can be suppressed to a low level only by selecting the position of the conductor. (2) The magnetic flux density can be suppressed to substantially zero at a specific position in the surrounding space. (3) The magnetic flux density distribution of the magnetic field around the parallel reciprocating feeder can be quickly simulated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a schematic explanatory diagram of a magnetic field caused by a current on a conductive wire.

FIG. 3 is a schematic explanatory diagram of the calculation principle of the present invention.

FIG. 4 is a flowchart of the apparatus of the present invention.

FIG. 5 is an explanatory diagram of a result of a trial calculation of a magnetic field density distribution by a conventional conductor arrangement.

FIG. 6 is an explanatory diagram of a trial calculation result of a magnetic field density distribution after the arrangement of the conductive wires is changed.

FIG. 7 is a diagram illustrating the principle of a method for determining the arrangement of the position-adjustable conductor.

FIG. 8 is an explanatory diagram of a trial calculation result of a magnetic field density distribution including a magnetic flux density of zero.

FIG. 9 is a block diagram of a method for determining an arrangement of a conductive wire whose position can be adjusted.

[Explanation of symbols]

 1 ... outbound route 2 ...Feeder  3, 4 ... return line 5 ... electric device 6 ... house 7 ... electronic flow utilization equipment 10 ...Means for determining current 11: means for selecting the arrangement of conductive wires 12 ... means for calculating magnetic flux density 13 ... means for setting environmental conditions 14 ... determining means 15

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor, Adult Fujino 1-3-8 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. Tokyo Branch (56) References JP-A-54-9809 (JP, A) Japanese Patent Publication No. 60-47820 (JP, B2) JP-A-8-505759 (JP, A) U.S. Pat. No. 5,086,543 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60M 1/00- 3/00

Claims (7)

(57) [Claims] 1. An at least two outgoing conductors including feeder wires and a return conductor.
Defines each conductor current in wire three or more reciprocating feed line consisting of a line, set the conductor arrangement in the feed line and the
Calculate the distribution of magnetic flux density around the feeder line based on each determined wire current, and calculate the magnetic flux density at a predetermined position in the circumference.
Fruit is determined whether less than the allowable value of the magnetic flux density at the predetermined position, said-out wire set when the result of the determination is negative
Resetting of the conductor arrangement by changing the position and the magnetic flux density
Of the distribution of the feeder line by repeating the recalculation of the distribution of
Position where the magnetic flux density at the predetermined position is less than the allowable value.
A method for suppressing the magnetic field around the feeder line, which is determined by the arrangement . 2. An at least two outgoing conductors including feeder wires and a return conductor.
Conductors in three or more reciprocating feeder lines
Means for determining the current, setting the position of the conductor within said feeder line
And means for selecting a wire arrangement to be changed, set by the selecting means
Current determined by the above-mentioned means in each conductor at the specified position
Operator to calculate the distribution of magnetic flux density around the feeder line due to
Step, giving a permissible value of the magnetic flux density at a predetermined position in the periphery.
Environmental condition input means, and the location determined by the arithmetic means.
It is determined whether the magnetic flux density at the fixed position is equal to or less than the allowable value.
Means when the result of the determination by the determination means is negative.
Change of the feeder line position by the selection means and the calculation
The recalculation of the magnetic flux density distribution by the step and the determination are repeated.
By returning, the position of the feeder wire is
It must be determined at a position where the magnetic flux density is below the allowable value.
Wire positioning device . 3. The position determining device according to claim 2, wherein said reciprocating power supply line is connected to an electric line having a return line consisting of two rails.
Feeder position determining device to be used as a vehicle feeder . 4. The position determining device according to claim 2 , wherein
The allowable value of the magnetic flux density at the predetermined position is determined by the image of the electron flow at the predetermined position based on the magnetic flux density at the predetermined position .
The position of the feeder, which will be the limit that will not be disturbed
Decision device . 5. The positioning apparatus of claim 4, the positioning device of the electric wire Ki becomes the electron current as the electron stream of the cathode ray tube at the predetermined position. In any position determining apparatus 6. The method of claim 2-5, comprising a distribution of magnetic flux density of the reciprocating feed line surrounding definitive to the arithmetic means calculated by the law of Maxwell
Feeder position determination device . 7. The feed line position determining device according to claim 2,
Two or more outgoing cables including feeder wires and trolley wires
An electric line having a return line and a return line consisting of two rails.
Power supply line for cars .