JP2004194486A - Power line for distribution line carrier communications and impedance unit for live-wire construction utilizing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power line for distribution line carrier communications capable of increasing impedance in the range of power line carrier communications by a grounding conductor and thereby of reducing the strength of leak electric field with the improvement of balancing at carrier frequency between an isolated wire and a neutral conductor. <P>SOLUTION: By replacing a portion of the grounding conductor 3 with a ferrite core 14 and by increasing the high frequency impedance of the grounding conductor, the impedance to ground of the neutral conductor 2 is made close to the impedance of the isolated wire 1b. This structure improves the balancing between the neutral conductor 2 and the isolated wire 1b and thereby reduces the leak of a carrier. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power line carrier communication communication power line using a power line as a communication line, and a power line for distribution line carrier communication capable of reducing a leakage electric field intensity of a signal generated because the power line is unbalanced at a high frequency. The present invention relates to a hot-line work impedance unit used for a power line.
[0002]
[Prior art]
Regarding power lines (distribution lines), one line is often grounded by a ground line regardless of a two-wire system or a three-wire system, and this grounded line is called a neutral line. Other lines that are not grounded are called ungrounded lines to distinguish them. There is a so-called power line carrier communication that performs communication by superimposing a high-frequency signal on such a power line. In conventional power line carrier communication, a plurality of power line carrier communication devices (generally, transceivers) connect one end of a coupling circuit (having two terminals) of each to a neutral line and the other end to a non-ground line. , Data is transmitted and received by a carrier wave (high frequency) via a power line, and communication is performed between them.
[0003]
[Problems to be solved by the invention]
However, because of the unbalanced configuration in which the neutral line is grounded by the ground line and the ungrounded line is not grounded, the neutral line and the ungrounded line are unbalanced as high-frequency signal lines. For this reason, the high-frequency signal transmitted from the power line carrier communication device leaks to the outside of the power line, the strength of the leaked electric field increases, and interference with other nearby power lines or other communication propagating through the communication line, etc. Was affected.
[0004]
[Means for Solving the Problems]
The power line for distribution line carrier communication according to the present invention is grounded by a ground line, and a neutral line connected to one end of the output of the power line carrier communication device using a high frequency signal as a carrier wave, and the output of the power line carrier communication device. A power line including an ungrounded line connected to the other end,
An impedance element having a predetermined impedance at a carrier frequency of the power line carrier communication is provided in series with the ground line, and a high-frequency impedance of the ground line is increased to increase a frequency of the neutral line and the non-ground line. In which the degree of equilibrium is increased.
[0005]
Further, the impedance unit for live line construction of the present invention is an impedance element having a predetermined impedance at a power line communication frequency,
Two terminals are provided on both poles of the impedance element, respectively, and are electrically connectable by being attached to a ground line for grounding a neutral line of a distribution line, and the two terminals are connected in the middle of the ground line. Then, the impedance element can be connected in series to the ground line without disconnecting the neutral state of the neutral line by disconnecting the ground line between the two terminals.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a configuration of a power line for distribution line carrier communication according to Embodiment 1 of the present invention. In FIG. 1, power line carrier communication devices 7a and 7b are connected via a coupling circuit 6a and 6b between a neutral line 2 and a non-ground line 1b which form a three-wire power line. Neutral wire 2 is grounded by ground wire 3. An impedance element 4 is replaced in the middle of the ground line 3. Power sources 5a and 5b supply power between neutral line 2 and non-ground lines 1a and 1b.
[0007]
Next, the operation of the power line for distribution line carrier communication of the first embodiment will be described with reference to FIG. The power line communication device 7a transmits (or receives) a high-frequency signal between the non-ground line 1b and the neutral line 2 by the coupling circuit 6a. A power line communication device 7b is connected between the non-ground line 1b and the neutral line 2 by a coupling circuit 6b. The power line communication devices 7a and 7b can communicate by transmitting and receiving high-frequency carriers using the ungrounded line 1b and the neutral line 2 as signal lines. For power line carrier communication, a frequency band of 1.7 MHz or more and 30 MHz or less is used. Neutral wire 2 is grounded by ground wire 3. An impedance element 4 having substantially flat inductance in the above-mentioned frequency band is attached (replaced) to the ground line 3.
[0008]
Next, the structure and characteristics of the impedance element 4 will be described. As shown in FIG. 2, the impedance element 4 has two partial cores 14a and 14b obtained by cutting a ferrite core 14 having a cylindrical shape (a cylindrical shape in the figure, but may be a polygonal shape) at a plane parallel to the axis of the cylinder. As shown in FIG. 3, a plurality of parts are replaced with ground wires 3. In addition, by using a ferrite core having a characteristic such that the magnetic characteristics do not deteriorate even at the upper limit of the carrier frequency band of the power line carrier communication, a predetermined impedance can be obtained within this frequency band.
Next, a state in which the ferrite core 14 is attached to the ground wire 3 will be described. FIG. 3 is a view showing a state in which the ferrite core 14 is mounted on the ground wire 3, and FIG. 4 is an explanatory sectional view thereof. After the partial cores 14 a and 14 b are attached so as to sandwich the ground line 3, they are fixed to the ground line 3 by an adhesive tape 17.
[0009]
The replacement of the ferrite core 14 increases the impedance of the ground line 3 in the carrier frequency band, so that the neutral line 2 is equivalently ungrounded in the same band, and the balance between the ungrounded line 1b and the neutral line 2 is improved. Improved in the same band. Since the degree of balance between the ungrounded line 1b and the neutral line 2 is improved in the same band, the common mode current when the carrier signal of the power line carrier communication is injected between the ungrounded line 1b and the neutral line 2 is reduced. The intensity of the leakage electric field generated by the common mode current can be reduced. By mounting the impedance element 4 as close as possible to the junction between the neutral line 2 and the ground line 3, the effect of improving the degree of balance between the ungrounded line 1b and the neutral line 2 can be further enhanced.
Since the power frequency is sufficiently lower than the carrier communication frequency, the change in the impedance of the ground line 3 due to the ferrite core 14 has almost no effect on the power frequency.
In the above description, the ferrite core 14 is described as attaching the partial cores 14a and 14b. However, the impedance element 4 may be formed by passing the ground wire 3 through the cylindrical ferrite core. Although only one ferrite core 14 is shown in the drawing, a plurality of ferrite cores 14 may be attached. Further, the ground wire 3 may be passed through one ferrite core 14 a plurality of times.
[0010]
Embodiment 2 FIG.
FIG. 5 is a configuration diagram showing a configuration of a power line for distribution line carrier communication according to Embodiment 2 of the present invention. In the following drawings, the same reference numerals indicate the same or corresponding parts, and thus detailed description thereof will be omitted. 5, the ferrite core winding unit 24 shown in FIG. 6 is used as the impedance element 4 shown in FIG.
[0011]
FIG. 7 is a configuration diagram showing a functional configuration inside the ferrite core winding unit 24 shown in FIG. The ferrite core winding unit 24 includes a connection portion 29a for connection to the ground wire 3, a connection portion 29b for connection to the ground side E, a ferrite core 30 having a ring shape, and a winding wound around the ferrite core 30. It includes a line portion 31. The winding part 31 is connected to the connection parts 29a and 29b. The winding part 31 is wound around the ferrite core 30 two or more times (the number of wires passing through the ring of the ferrite core is two or more).
[0012]
While the ground wire 3 of the first embodiment shown in FIG. 1 only penetrates the hollow portion of the ferrite core 14 once, in the second embodiment, the winding part 31 is wound around the ferrite core 30 for two or more turns. Since the inductance increases with the square of the number of turns, the increase in the impedance of the impedance element in the power line carrier communication band is larger than that of the impedance element 4 shown in the first embodiment. In this case, the ground line is more reliably equivalently ungrounded, and the degree of balance between the ungrounded line 1b and the neutral line 2 is improved in the same band. By improving the degree of balance between the ungrounded line 1b and the neutral line 2 in the same band, the common mode current when the carrier signal of the power line carrier communication is injected between the ungrounded line 1b and the neutral line 2 is reduced. Thus, the intensity of the leakage electric field generated by the common mode current can be reduced.
Further, similarly to the mounting position of the impedance element 4 described in the first embodiment, the ferrite core winding unit 24 is mounted at a position as close as possible to the junction between the neutral wire 2 and the ground wire 3 so that the non-ground wire 1b And the effect of improving the balance of the neutral wire 2 can be enhanced. Further, a plurality of ferrite core winding units 24 may be connected in series.
[0013]
Embodiment 3 FIG.
FIG. 7 is a configuration diagram showing a configuration of a power line for power line carrier communication according to Embodiment 3 of the present invention, in which an impedance upper 35 is used as the impedance element 4 in FIG.
[0014]
FIG. 8 is a configuration diagram showing a configuration of the impedance upper 35 shown in FIG. The impedance upper 35 includes a connecting portion 29 a for connecting to the ground line 3, a connecting portion 29 b for connecting to the ground side E, and a coil 41. The coil 41 is connected to the connection portions 29a and 29b.
[0015]
The coil 41 increases the impedance in the frequency band of the power line carrier communication, improves the degree of balance between the ungrounded line 1b and the neutral line 2, and reduces the strength of the leaked electric field. Here, the coil 41 may be an air-core coil or a coil in which a ferrite core is wound around a bobbin provided on a core.
[0016]
Embodiment 4 FIG.
Since power line carrier communication is a recently emerging technology in which many power lines have already been installed, power lines for distribution line carrier communication use existing power lines rather than newly constructed ones to carry out carrier communication. Often done. Therefore, it is preferable that the mounting of the impedance element 4 shown in FIG.
When the ferrite core 14 of the first embodiment shown in FIG. 2 is attached, it is not necessary to cut the ground wire 3 so that the work can be performed with the live wire. However, in the case of the second and third embodiments, since the ground wire 3 must be cut and the impedance element 4 must be connected, in order to secure the ground state of the neutral wire 2 during this cut, for example, It is inefficient because a temporary replacement ground wire is required.
The impedance unit 9 for hot wire construction of FIG. 9 can be attached by hot wire work by replacing the impedance element 4 of the power line for distribution line carrier communication according to the second to third embodiments of the present invention. It is like that.
[0017]
FIG. 10 is a configuration diagram showing a functional configuration of a live wire construction ferrite winding unit 45 of the present embodiment, which embodies the hot wire construction impedance unit 9 of FIG.
FIG. 11 is a structural diagram showing a detailed structure of a caulked portion inside the live wire construction ferrite core winding unit 45 shown in FIG. The ferrite core winding unit 45 for live wire construction includes a first caulking portion 50a for connection to the ground wire 3, a second caulking portion 50b for connection to the ground E, a ferrite core 30, and a winding portion 31. ing. The winding part 31 is connected to the first caulking part 50a and the second caulking part 50b. The winding part 31 is wound around the ferrite core 30 two or more times (the number of through wires in the ring is two or more).
[0018]
The first and second caulking portions in FIG. 10 are composed of clamps 53a, 53b, bolts 54a, 54b, 54c, 54d, nuts 55a, 55b, 55c, 55d, a needle 56, and a connecting portion 57, as shown in FIG. ing.
[0019]
Next, a method for attaching the ferrite core winding unit 45 for live wire construction shown in FIG. 10 to the ground wire 3 by live wire work will be described with reference to FIG. In FIG. 12A, the ground line 3 is covered with a coating 3X. The ground wire 3 is connected to the terminals (first and second caulked portions 50a and 50b) of the ferrite core winding unit 45 for hot wire work (either from above the coating 3X or after stripping the coating 3X). It is sandwiched by the clamps 53a and 53b and tightened by bolts 54a, 54b, 54c and 54d and nuts 55a, 55b, 55c and 55d, as shown in FIG. At this time, the needle 56 penetrates the coating 3X, and the ground wire 3 and the clamp are electrically connected. Next, as shown in FIG. 12C, the ground wire 3 is cut between the first and second clamps 50a and 50b. Thus, the ferrite core winding unit 45 for live wire work can be attached without releasing the ground state.
[0020]
Also, by attaching the ferrite core winding unit 45 for live wire construction to the ground wire 3 and then cutting the ground wire 3, the impedance in the power line carrier communication band increases, and the ungrounded wire 1b and the neutral wire 2 and the strength of the leakage electric field can be reduced.
Although not shown in the drawing, when removing the ferrite core winding unit 45 for live wire work, first, the ground wires 3 that have been cut are connected to each other, and then the first and second clamps are opened. It can be removed while keeping the ground.
[0021]
Embodiment 5 FIG.
FIG. 13 is a functional configuration diagram of a live wire construction impedance upper 61 according to a fifth embodiment which embodies the hot wire construction impedance unit 9 of FIG. 9 of the fourth embodiment, and FIG. 14 is a structural diagram thereof.
The live wire construction impedance upper 61 has a caulked portion 50a for connection to the ground wire 3, a caulked portion 50b for connection to the ground E, a coil 41, and a movable ferrite core 60 capable of adjusting the inductance of the coil 41. ing. The movable ferrite core 60 has a structure in which the inductance of the coil 41 can be adjusted by entering and exiting the coil 41.
The structure of the caulked portion is the same as that of the fourth embodiment shown in FIG.
[0022]
Further, the method of attaching the live wire construction impedance upper 61 to the ground wire 3 is the same as the method shown in FIG. 12 of the fourth embodiment of the present invention.
[0023]
By attaching the impedance upper 61 for live wire construction to the ground wire 3, the impedance of the ground wire 3 in the power line carrier communication band increases, the balance between the non-ground wire 1b and the neutral wire 2 improves, and the leakage electric field increases. Can be reduced in strength. In addition, since the impedance of the ground line 3 can be adjusted to some extent by the movable ferrite core 60, the impedance can be adjusted according to the frequency of the power line carrier used or according to the degree of balance between the non-ground line 1b and the neutral line 2, The degree of balance can be further increased.
[0024]
【The invention's effect】
Since the power line for power line carrier communication of the present invention is configured as described above, it is possible to increase the impedance of the ground line in the band of power line carrier communication, and therefore, the non-ground line and the neutral line This has the effect of improving the degree of balance at the carrier frequency and reducing the intensity of the leaked electric field.
[0025]
ADVANTAGE OF THE INVENTION According to the impedance unit for live-line construction according to this invention, the clamp of the impedance unit for live-line construction is attached to the ground line in a live state, and then the ground line is cut, thereby impairing the live state of the ground line. Therefore, an effect is obtained that an impedance unit for live wire construction can be inserted in series in the middle of the ground wire.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a power line for distribution line carrier communication according to Embodiment 1 of the present invention.
FIG. 2 is a structural diagram showing a structure of a ferrite core of FIG.
FIG. 3 is an explanatory diagram illustrating an attached state of a ferrite core of FIG. 1;
FIG. 4 is a cross-sectional view of the ferrite core of FIG.
FIG. 5 is a configuration diagram of a distribution line carrier communication power line according to a second embodiment of the present invention.
FIG. 6 is a structural diagram showing the structure of the ferrite core winding unit of FIG. 5;
FIG. 7 is a configuration diagram of a power line for distribution line carrier communication according to Embodiment 3 of the present invention.
FIG. 8 is a structural diagram showing a structure of an impedance upper in FIG. 7;
FIG. 9 is a connection explanatory view of a live-line construction impedance unit according to Embodiment 4 of the present invention.
FIG. 10 is a structural view showing the structure of the impedance unit for live-line work in FIG. 9;
FIG. 11 is a partial detailed structural view of FIG. 10;
FIG. 12 is a configuration diagram of an impedance unit for live wire work according to a fifth embodiment of the present invention.
FIG. 13 is a structural view of the live-line work impedance unit shown in FIG.
[Explanation of symbols]
1a, 1b ungrounded wire, 2 neutral wire, 3 grounded wire,
4 impedance element, 5a, 5b power supply,
6a, 6b coupling circuit, 7a, 7b power line carrier communication device,
14 ferrite core, 14a, 14b partial core,
17 adhesive tape, 24 ferrite core winding unit,
29a, 29b connection part, 30 ferrite core, 31 winding,
35 impedance upper, 41 coil,
45 Ferrite core winding unit for live wire construction,
50a first caulking part, 50b second caulking part,
53a, 53b clamp, 56 needles, 60 movable ferrite core,
61 Impedance upper for live line construction.

Claims (9)

A neutral line connected to one end of an output terminal of the power line communication device that is grounded by a ground line and uses a high frequency signal as a carrier wave, and a non-ground line connected to the other end of the output terminal of the power line communication device. And power lines, including
An impedance element having a predetermined impedance at a frequency of the high-frequency signal, which is connected in series along the ground line,
A power line for distribution line carrier communication, wherein the high-frequency impedance of the ground line is increased to increase the balance between the neutral line and the ungrounded line. The power line according to claim 1, wherein the impedance element includes a cylindrical ferrite core having the ground wire penetrating therethrough. The impedance element is characterized in that a hollow cylindrical ferrite core is formed by arranging a plurality of partial cores divided by a plane parallel to the axis of the cylinder around the ground line. The power line for distribution line carrier communication according to claim 1. The power line for distribution line carrier communication according to claim 1, wherein the impedance element includes a ring-shaped ferrite core in which the ground wire passes through at least twice. The power line for distribution line carrier communication according to claim 1, wherein the impedance element includes a coil. An impedance element having a predetermined impedance at the power line carrier communication frequency,
A terminal is provided on each of the two poles of the impedance element and is attached to a ground line for grounding a neutral line of a distribution line, and is provided with a terminal that can be electrically connected to the ground line. The terminal is connected in the middle of the ground line. Then, the impedance element can be connected in series to the ground line without disconnecting the grounding state of the neutral line by cutting the ground line between the terminals of the two poles. For impedance unit. The impedance unit according to claim 6, wherein the impedance element includes a ring-shaped ferrite core in which the ground wire passes through at least twice. The impedance unit according to claim 6, wherein the impedance element is a coil. The impedance unit for live-line work according to claim 8, further comprising a movable ferrite core attached so as to be able to be inserted into and removed from the coil.

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