JP2008271507A - Method and apparatus for preventing signal leakage in power line communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more surely prevent a signal from being leaked or interfered when performing power line communication. <P>SOLUTION: The present invention relates to a signal leakage prevention method for communication performed between power line modems connected to a plurality of pull-in lines branched from a predetermined branching point, wherein each of the pull-in lines to which the power line modems are connected, comprises a low-pass filter, each of the pull-in lines comprises an RC serial circuit connected at a downstream side rather than a position where the low-pass filter is provided, a power frequency cutoff element is provided of which one end is connected at a downstream side rather than a position at which the RC serial circuit of the first pull-in line is connected, and of which another end is connected at a downstream side rather than a position at which the RC serial circuit of the second pull-in line is connected, and the power line modems are connected at a downstream side rather than a position where the RC serial circuits of the pull-in lines are connected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a signal leakage prevention method and a signal leakage prevention apparatus for reliably preventing signal leakage and interference when performing power line communication.

In recent years, development of a power line communication system that performs communication using a power line has been promoted. In a power line communication system, a technique for providing a blocking filter on a power line has been developed in order to prevent signal interference and leakage. For example, Patent Document 1 discloses a configuration in which a blocking filter that blocks high-frequency signals generated by power line communication is configured by a combination of a reactor and a capacitor circuit. Patent Document 2 discloses a data transmission method using an optical fiber and a power line extended from a power transmission line. A first demultiplexing filter is provided at the end of the optical fiber, and a second power line is provided on the customer-side power line. A demultiplexing filter is provided. Further, Patent Document 3 discloses a blocking filter provided between an indoor power line and an outdoor power line of a power line communication system. For example, an inductor provided in series with each conductive line, and between the conductive lines on the indoor power line side, is disclosed. A connected RC series circuit; and a capacitor connected between the conductive wires on the outdoor power line side of the inductor.
JP 2005-203915 A JP 2002-353864 A JP 2003-218754 A

  By the way, since noise leakage prevention processing or the like is not normally performed on the power line, a technique for more reliably preventing signal leakage and interference is required in the power line communication system. For this purpose, it is required to arrange a circuit element such as a filter having an appropriate configuration at an appropriate position on the power line constituting the power line communication system.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a signal leakage prevention method and a signal leakage prevention apparatus that more reliably prevent signal leakage and interference when performing power line communication. And

  In order to solve the above and other problems, one aspect of the present invention is a signal leakage prevention method for communication performed between power line modems connected to each of a plurality of service lines that branch from a predetermined branch point. , A low pass filter is provided for each of the lead-in lines to which the power line modem is connected, and an RC series circuit connected to a downstream side of the position where the low-pass filter is provided is provided for each of the lead-in lines, one end of which Electric power connected to the downstream side of the first lead-in line from the position where the RC series circuit is connected, and connected to the downstream side of the second lead-in line from the position where the RC series circuit is connected. A frequency cutoff element is provided, and each power line modem is connected to a downstream side of a position where the RC series circuit of each lead-in line is connected.

  By such an aspect, it becomes possible to more reliably prevent signal leakage and interference when performing power line communication. That is, in the signal leakage prevention method according to the present invention, as a blocking filter provided to prevent signal interference and leakage, a low-pass filter and an RC series circuit are respectively provided on a service line to which a power line modem is connected, and A power line modem is connected downstream of the position where the RC series circuit is connected, and the first service line and the second service line are connected downstream of the position where the RC series circuit is connected by a power frequency cutoff element. Connecting. This makes it possible to more reliably prevent signal leakage and interference while using the downstream side of the blocking filter of the lead-in line for power line communication.

  In the signal leakage prevention method, the lead-in wire includes a first electric wire and a second electric wire, and the low-pass filter includes a first coil on the first electric wire, and the second electric wire. Provided with a second coil, and the first electric wire and the second electric wire are connected via a first capacitor on the upstream side of the first coil and the second coil. The RC series circuit may be configured by connecting the first electric wire and the second electric wire to a second capacitor and a resistor in series.

  According to such an aspect, an LC low-pass filter and an RC series circuit can be configured using coils and capacitors that are available in large quantities at a low price in the market. Therefore, a blocking filter can be inexpensively provided for all incoming lines in the power supply area. Can be installed.

  Furthermore, in the signal leakage prevention method, the low-pass filter, the RC series circuit, and the power frequency cutoff element may be accommodated in an outer case of the power line modem.

  By such an aspect, it is possible to protect the above devices and components from wind and rain. The blocking filter and the power frequency cutoff element can be installed together with the power line modem.

  At this time, if the power line modem is connected to a communication network constituted by the lead-in line and a communication network different from the communication network so as to be able to communicate with each other, the power line modem is accommodated in the outer case. A blocking filter and a power frequency cutoff element can be installed together.

  Another aspect of the present invention is configured to include a power line modem connected to each of a plurality of service lines that branch from a predetermined branch point, and each of the service lines to which the power line modem is connected is provided with a low-pass filter, An RC series circuit connected downstream of the position where the low-pass filter is provided is provided for each of the service lines, and one end of the RC circuit is connected downstream of the position where the RC series circuit of the first service line is connected. And a power frequency cutoff element having the other end connected downstream of the position where the RC series circuit of the second service line is connected, and each power line modem is connected to the RC series of each service line. A signal leakage prevention apparatus for use in a power line communication system connected downstream of a position where a circuit is connected, the low pass filter, the RC series circuit, and the power frequency Characterized in that it comprises a blocking element.

  By such an aspect, it becomes possible to more reliably prevent signal leakage and interference when performing power line communication.

  In addition, the problems disclosed by the present application and the solutions thereof will be clarified by the column of the best mode for carrying out the invention and the drawings.

  It is possible to more reliably prevent signal leakage and interference when performing power line communication.

[First embodiment]
=== Overall structure ===
FIG. 1 shows a first embodiment of a signal leakage prevention method and a power line communication system according to the present invention.
The power line communication system 1000 according to the present embodiment includes a main station side PLC (externally installed on a service line 800 for supplying power from the pole transformer 200 to the power consuming apparatus 500 in the customer 600's home. Power line communication) modem 300 and slave station side PLC modem 310 installed in the house are connected.
The master station side PLC modem 300 and the slave station side PLC modem 310 correspond to the power line modem described in the claims.

  The pole transformer 200 converts a voltage of 6600 V supplied through the distribution line 700 into a voltage of 200 V or 100 V and supplies the converted voltage to the lead-in wire 800.

  The lead-in line 800 is drawn into the home of each customer 600 and supplies power to the power consumption device 500 in the home. In the present embodiment, the lead-in line 800 refers to a power line from the pole transformer 200 to the in-house power consumption device 500 and may include indoor wiring. The lead-in wire 800 is constituted by two or three electric wires. When power is supplied to each customer 600 by a single-phase three-wire system, the lead-in wire 800 is constituted by three electric wires, and when it is carried out by a single-phase two-wire type, the lead-in wire 800 is provided by two electric wires. Consists of. The power consuming apparatus 500 is a home appliance such as a television, a refrigerator, or a lighting fixture.

  In each customer 600, a power generation device 510 is also connected to the service line 800. The power generation device 510 is configured by, for example, a solar power generation system or a cogeneration system. The electric power generated by the power generation device 510 is supplied to the power consuming device 500 through the service line 800 in the home of each customer 600.

  Further, one or more branch lines 810 branch from the service line 800, and the master station side PLC modem 300 and the slave station side PLC modem 310 are connected to the branch line 810. These PLC modems 300 and 310 superimpose and separate signals on the AC power flowing through the lead-in line 800. As a result, the master station PLC modem 300 and the slave station PLC modem 310 can exchange signals via the lead-in line 800.

  The master station PLC modem 300 is communicably connected to the master station communication device 400 via a communication cable 900. The communication cable 900 is configured using, for example, an optical fiber or metal as a signal transmission medium. The communication cable 900 configures, for example, the Internet or a LAN (Local Area Network).

  The master station side PLC modem 300 is accommodated in the exterior case 301 and installed near the pole transformer 200 on the utility pole. The exterior case 301 also houses a blocking filter 100 described later. By accommodating the master station PLC modem 300 and the blocking filter 100 in the outer case 301, these devices can be protected from wind and rain. Also, the installation work of the blocking filter 100 can be performed simultaneously with the installation work of the master station PLC modem 300.

  The master station side communication device 400 is configured by, for example, a computer installed at a sales office of an electric power company. The master station side communication device 400 is communicably connected to a computer (not shown) installed in the power plant or substation, and receives various information such as the operating status of the power plant or substation, failure or accident. can do.

  The slave station side PLC modem 310 is communicably connected to the slave station side communication device 410 via the communication cable 900. The slave station side communication device 410 is connected to the power generation device 510 and outputs various control signals for controlling the power generation device 510. The slave station side PLC modem 310 and the slave station side communication device 410 may be accommodated in a meter box of each house, for example. Further, the slave station side PLC modem 310 and the slave station side communication device 410 may be configured as one unit configured integrally. The slave station side communication device 410 may be configured in the power generation device 510. Further, the slave station side communication device 410 may be constituted by a personal computer.

=== Signal Leakage Prevention Method ===
Next, a signal leakage prevention method according to this embodiment will be described.
As shown in FIG. 1, in the power line communication system 1000 according to the present embodiment, the pole transformer 200 is the most among the branch points where the branch line 810 connected to the PLC modems 300 and 310 branches from the service line 800. Blocking filter 100 on lead-in line 800 closer to pole transformer 200 than the branch point near (in the example shown in FIG. 1, the branch point where branch line 810 to which master station PLC modem 300 is connected branches from lead-in line 800). Is provided. Thereby, it is possible to prevent signal leakage and interference when communication is performed between the master station side communication device 400 and the slave station side communication device 410.

  Here, the blocking filter 100 according to the present embodiment includes an attenuation characteristic improving circuit 120 in addition to the LC low-pass filter 110. An example of the blocking filter 100 is shown in FIG.

  In the example shown in FIG. 2, the LC low-pass filter 110 is provided on the coil 111 provided on the electric wire (first electric wire) 801 constituting the lead-in wire 800 and on the electric wire (second electric wire) 802 constituting the lead-in wire 800. And a capacitor 112 that connects the electric wires 801 and 802 between the coils 111 and the pole transformer 200.

  Of course, the LC low-pass filter is not limited to the configuration shown in FIG. 2. For example, the coil 111 shown in FIG. 2 can be configured by appropriately connecting a plurality of coils in series or in parallel. Similarly, the capacitor 112 shown in FIG. 2 can be configured by appropriately connecting a plurality of capacitors in series or in parallel.

  The attenuation characteristic improvement circuit 120 is an RC series circuit in which a capacitor 121 and a resistor 122 are connected in series. The branch point where the branch line 810 to which the master station PLC modem 300 is connected branches, the LC low-pass filter 110, and the like. The two electric wires 801 and 802 constituting the lead-in wire 800 are connected in between.

  In this way, between the branch point closest to the pole transformer 200 and the pole transformer 200, the LC low-pass filter 110 is provided in series on the electric wires 801 and 802 constituting the lead-in wire 800, and the LC low-pass filter 110 And the branch station, the wires 801 and 802 are connected by an attenuation characteristic improving circuit 120 in which a capacitor 121 and a resistor 122 are connected in series, whereby the master station side PLC modem 300 and the slave station side are connected. It is possible to more reliably reduce signal interference and leakage when signals are exchanged with the PLC modem 310. The experimental results are shown in FIGS.

  FIG. 3 is a graph showing the attenuation characteristics when the blocking filter 100 having only the LC low-pass filter 110 and not including the attenuation characteristic improving circuit 120 is used. FIG. 4 is a graph showing the attenuation characteristics of the LC low-pass filter 110 and the attenuation characteristic improvement. It is a graph which shows the attenuation | damping characteristic at the time of using the blocking filter 100 of the structure based on a present Example provided with the circuit 120. FIG.

  As shown in FIG. 3, when the blocking filter 100 having no attenuation characteristic improvement circuit 120 is used, the attenuation characteristic is only about −42 dB, whereas the attenuation characteristic improvement circuit 120 is provided. When the blocking filter 100 is used, an attenuation characteristic of about −50 dB can be obtained.

  In this manner, by inserting the blocking filter 100 having the attenuation characteristic improving circuit 120 according to the present embodiment into the lead-in line 800, it is possible to more reliably prevent signal leakage and interference when performing power line communication. It becomes.

  By the way, in the power line communication system 1000 according to the present embodiment, the master station side communication device 400 and the slave station side communication device 410 are communicably connected. Here, for example, when a power failure occurs due to an accident or the like in a power distribution facility, it is necessary to stop the power generation device 510 installed in the home of each customer 600. The device 400 transmits a power generation stop request for stopping the power generation by the power generation device 510 installed in the home of each customer 600 to each slave station side communication device 410, whereby each customer 600 The power generation device 510 can be stopped.

  That is, the slave station side communication device 410 outputs a control signal for stopping the power generation device 510 in response to the power generation stop request, and when this control signal is input to the power generation device 510, the power generation device of each consumer 600 Power generation by 510 stops.

  At this time, in the present embodiment, since the blocking filter 100 having the attenuation characteristic improving circuit 120 is inserted into the lead-in line 800, there is no signal leakage or interference, and the master station side communication device 400 to the slave station side communication device. The power generation stop request can be reliably transmitted to 410. For this reason, it becomes possible to stop a power generator reliably.

[Second Embodiment]
Next, a signal leakage prevention method and a power line communication system according to a second embodiment of the present invention will be described with reference to FIGS. In order to simplify the description, the same components as those in the first embodiment are denoted by the same reference numerals, the description thereof will be omitted as appropriate, and differences will be mainly described.

  Also in the present embodiment, the lead-in line 800 refers to a power line from the pole transformer 200 to the in-house power consumption device 500 and may include indoor wiring. The lead-in wire 800 is constituted by two or three electric wires including the first electric wire and the second electric wire.

  In the present embodiment, unlike the first embodiment, a lead-in wire 800 (first lead-in wire and first lead-in wire and the lead-in wire 800) branched from the predetermined branch point on the secondary side of the pole transformer 200 into each customer 600 home. Including the second lead-in wire). The configuration of each blocking filter 100 can be, for example, the configuration shown in FIG. 2 of the first embodiment, and is a combination of the LC low-pass filter 110 and the attenuation characteristic improving circuit 120.

  The master station side PLC modem 300 and the slave station side PLC modem 310 are connected to the downstream side of the blocking filter 100 (the power consuming apparatus 500 side) of one of the branched service lines 800. Further, the slave station side PLC modem 310 is connected to the downstream side of the blocking filter 100 of the other lead-in line 800. The master station side PLC modem 300 and each slave station side PLC modem 310 are connected to the service line 800 via a branch line 810 provided by branching from the branch point of each service line 800.

  Further, the service line 800 or the branch line 810 to which the master station side PLC modem 300 is connected and each of the other service line 800 or the branch line 810 to which the slave station side PLC modem 310 is connected are arranged downstream of the blocking filter 100. Each is connected by a power frequency cutoff element 130.

  In the case of the present embodiment, each lead-in line 800 and each branch line 810 on the downstream side of each blocking filter 100 constitute a PLC communication line, and upstream of each blocking filter 100 (secondary side of the pole transformer 200). The high frequency signal of the PLC does not flow to On the other hand, between the branch line 810 to which the master station side PLC modem 300 is connected and the branch line 810 to which the slave station side PLC modem 310 is connected, the power frequency cutoff element 130 blocks the low frequency power frequency while blocking the high frequency. Only the PLC signal is exchanged, and the PLC can function as a communication line.

  As the power frequency cutoff element, for example, a capacitor having an appropriate capacity selected according to required characteristics as a PLC communication line can be used. As shown in FIG. 6, if the lead-in wire 800 is a two-wire type, each power frequency cutoff element 130 includes the first electric wire 801 and the second electric wire 802 of one lead-in wire 800 and the first of the other lead-in wires 800. What is necessary is just to comprise from the capacitor 131 which each connects between the electric wire 801 and the 2nd electric wire 802.

  Generally, the blocking filter 100 needs to be configured by including an LC low-pass filter 110 having a coil 111 having a current capacity exceeding the design maximum value of the passing current. When the blocking filter 100 is provided in the lead-in line 800 directly below the pole transformer 200 as in the first embodiment, the passing current is 100A depending on the number of downstream customers 600 and the power usage state there. In some cases, it may not always be a good idea to provide one blocking filter 100 under such current conditions.

  In such a case, with the configuration as described above, the coil 111 of the LC low-pass filter 110 may be designed with the contracted current capacity of each customer 600 as an upper limit, and the size of each blocking filter 100 can be reduced. , It will be possible to reduce the cost.

  As in the first embodiment, the master station side PLC modem 300 and the blocking filter 100 can be accommodated in one outer case 301. In this case, the master station side PLC modem 300 and the blocking filter 100 are installed in the rain or the like. Can be protected from. Also, the installation work of the blocking filter 100 can be performed simultaneously with the installation work of the master station PLC modem 300.

  Further, the blocking filter 100 and the power frequency cutoff element 130 may be accommodated together in the outer case 302. In this case, the blocking filter 100 and the power frequency cutoff element 130 (that is, the capacitor 131 constituting the blocking filter 100 and the capacitor 131) are protected from wind and rain. Can be protected. Furthermore, each blocking filter 100 and each power frequency cutoff element 130 may be accommodated together in the outer case 301 of the master station PLC modem 300. Such an exterior case can be installed in the vicinity of the pole transformer 200, for example.

  The power line communication system 1000 according to the present embodiment has been described above. However, according to the power line communication system 1000 according to the present embodiment, it is possible to more reliably prevent signal leakage and interference when performing power line communication. It becomes.

  The above embodiment is for facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

It is a figure which shows the whole structure of the power line communication system which concerns on 1st Example of this invention. It is a figure which shows the blocking filter which concerns on this Embodiment. It is a figure which shows the attenuation characteristic at the time of using the blocking filter which is not provided with an attenuation characteristic improvement circuit. It is a figure which shows the attenuation | damping characteristic at the time of using the blocking filter provided with the attenuation | damping characteristic improvement circuit which concerns on this Embodiment. It is a figure which shows the whole structure of the power line communication system which concerns on 2nd Example of this invention. FIG. 6 is a schematic circuit diagram showing a part of FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Blocking filter 110 LC low pass filter 111 Coil 112, 121, 131 Capacitor 120 Attenuation characteristic improvement circuit 122 Resistance 130 Power frequency cutoff element 200 Pillar transformer 300 Master station side PLC modem 301, 302 Outer case 310 Slave station side PLC modem 400 Master station side communication device 410 Slave station side communication device 500 Power consuming device 510 Power generation device 600 Customer 700 Distribution line 800 Service line 801, 802 Electric wire 810 Branch line 900 Communication cable 1000 Power line communication system

Claims (5)

A signal leakage prevention method for communication performed between power line modems connected to each of a plurality of service lines branching from a predetermined branch point,
A low pass filter is provided for each of the service lines to which the power line modem is connected,
An RC series circuit connected to the downstream side of the position where the low-pass filter is provided is provided for each of the lead-in lines,
One end of the first lead-in wire is connected to the downstream side of the position where the RC series circuit is connected, and the other end is connected to the downstream side of the second lead-in line to which the RC series circuit is connected. Power frequency cutoff element to be provided,
A signal leakage prevention method, wherein each power line modem is connected to a downstream side of a position where the RC series circuit of each lead-in line is connected. The signal leakage prevention method according to claim 1,
The lead-in wire is configured to include a first electric wire and a second electric wire,
The low-pass filter includes a first coil provided on the first electric wire, a second coil provided on the second electric wire, and the first coil and the second electric wire connected to the first coil. And by connecting via a first capacitor upstream of the second coil,
The RC series circuit is constituted by connecting the first electric wire and the second electric wire with a second capacitor and a resistor in series, and the signal leakage preventing method. The signal leakage prevention method according to claim 1,
The signal leakage prevention method, wherein the low-pass filter, the RC series circuit, and the power frequency cutoff element are accommodated in an outer case of the power line modem. The signal leakage prevention method according to claim 3,
A signal leakage prevention method, wherein a power line modem accommodated in the exterior case connects a communication network constituted by the lead-in line and another communication network so as to communicate with each other. A power line modem connected to each of a plurality of service lines branched from a predetermined branch point;
A low pass filter is provided for each of the service lines to which the power line modem is connected,
An RC series circuit connected to the downstream side of the position where the low-pass filter is provided is provided for each of the lead-in lines,
One end of the first lead-in wire is connected to the downstream side of the position where the RC series circuit is connected, and the other end is connected to the downstream side of the second lead-in line to which the RC series circuit is connected. Power frequency cutoff element to be provided,
A signal leakage prevention apparatus used in a power line communication system for connecting each power line modem to a downstream side of a position where the RC series circuit of each lead-in line is connected,
An apparatus for preventing signal leakage, comprising: the low-pass filter, the RC series circuit, and the power frequency cutoff element.

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