JP6492256B2 - Power line communication system and watt-hour meter used therefor - Google Patents

Description

  The present invention relates to a power line communication system, and more particularly, to a power line communication system suitable for monitoring power consumption and a power meter used therefor.

  In recent years, the number of cases where nuclear power plants cannot be operated due to the effects of the earthquake has increased, and there has been no margin for power supply. In response to this, the introduction of a remote power metering system and a monitoring system that visualizes the power consumption of consumers and promotes power saving (hereinafter referred to as “home system”) has been studied at a rapid pace (see Patent Documents 1 to 3).

JP 2007-019696 A JP 2010-288287 A JP 2011-199909 A

  The remote meter reading system operated by the electric power company and the customer premises system cannot be made the same system due to security problems, and therefore need to be constructed as separate systems. There are two types of power line communications that can be used in Japan, one that uses a low frequency band of 10k to 450kHz and one that uses a wide frequency band of 2M to 30MHz. Only indoor use is allowed due to regulatory restrictions. Since the remote meter reading system communicates using a power line drawn from the outdoors, the low frequency band is inevitably used. As for the in-home system, it is desirable to use the low frequency band for the purpose of avoiding interference with indoor LAN products using the high frequency band.

  However, when the low frequency band is used in both the remote meter reading system and the home system, there will be two systems that use the same frequency band on the same power line, and interference between each other can be avoided. There is no problem. In order to avoid this problem, it is conceivable to divide the frequency of 10 kHz to 450 kHz. However, since the band is originally narrow, problems such as a decrease in transmission speed and a decrease in noise resistance occur when the frequency is divided. Also, there is a plan to divide both, but it is necessary to synchronize the modem of the remote meter reading system and the modem of the home system, and there is a problem that the system becomes complicated.

  The present invention has been made to solve the above problems, and an object of the present invention is to allow both a remote meter reading system and a home system to coexist using a low frequency band on a common power line. An object of the present invention is to provide a power line communication system. Another object of the present invention is to provide a watt-hour meter for realizing such a power line communication system.

  In order to solve the above problems, a power line communication system according to the present invention is a single-phase three-wire low-voltage distribution line comprising a ground line extending from a transformer to a consumer, a first non-ground line, and a second non-ground line. And a power line communication system installed in a distribution facility having a watt-hour meter connected to the low-voltage distribution line and measuring the power consumption of the consumer, and connected to the low-voltage distribution line near the transformer The first power line modem, the second power line modem connected to the low voltage distribution line closer to the consumer than the watt hour meter, and the closer to the consumer than the connection point of the first power line modem A third power line modem connected to a low voltage distribution line and performing power line communication with the first and second power line modems, and the third power line modem on the low voltage distribution line; A first bypass capacitor that connects the ground line and the first non-ground line; and a third power line modem on the low-voltage distribution line, provided at a connection point of the low-voltage distribution line; A second bypass capacitor for connecting to a second non-ground line, wherein the first power line modem is connected to the ground line of the low-voltage distribution line by an inductive coupling method, and the second power line The modem is connected to at least two of the ground line, the first non-ground line, and the second non-ground line of the low-voltage distribution line by a capacitive coupling method, and the third power line modem has one end The first lead line connected to the ground line is connected by an inductive coupling method, and the other end of the first lead line is connected to the first lead line via the first bypass capacitor and the second lead line. 1 ungrounded Is connected to, and, characterized in that via said second bypass capacitors and the third lead wire is connected to the second non-grounding wire.

  According to the present invention, a communication route (A route) between the first power line modem and the third power line modem, a communication route (B route) between the second power line modem and the third power line modem, and Can be separated by first and second bypass capacitors. Therefore, it is possible to prevent mutual interference between the power line communication of the A route constituting the remote meter reading system and the power line communication of the B route constituting the in-home system, and using the same frequency band on the common power line, two different Power line communication can coexist.

  Further, according to the present invention, the third power line modem serves as both the A-route and B-route power line modems, so that the entire system can be reduced in size. In addition, when the signal injection point is provided near the bypass capacitor, positively utilizing the characteristic of the capacitive coupling method that the signal injection efficiency is poor, the power line communication of the A route and the power line communication of the B route can be reliably performed. Can be separated.

  In the present invention, it is preferable that the third power line modem is provided in the watt-hour meter. As described above, the third power line modem serves as both the A-route and B-route power line modems and is small in size. Therefore, when the third power line modem is incorporated in the watt-hour meter, the watt-hour meter itself is used. It can be downsized. Therefore, a system can be constructed using a small and high-performance watt-hour meter that can be installed in a narrow space.

  The power line communication system according to the present invention further includes a distribution board for branching the low-voltage distribution line closer to the consumer than the watt-hour meter, and the second power line modem is connected to the home wiring branched from the distribution board. It is preferable that they are connected. According to this configuration, since the distance between the second power line modem and the third power line modem is short, even if a capacitive coupling method with poor signal injection efficiency is adopted, communication can be sufficiently performed, and the remote meter reading system side is reached. Interference can be prevented.

  In the present invention, it is preferable that the third power line modem transmits meter reading data of the power consumption measured by the watt hour meter to the first or second power line modem. According to this configuration, both the remote meter reading system and the home system can coexist on a common low-voltage distribution line.

  In the present invention, the watt-hour meter includes a metering unit that actually measures the power consumption, a first printed circuit board on which the metering unit is mounted, and a second module on which the third power line modem is mounted. A part of the ground line, a part of the first non-ground line, and a part of the second non-ground line are provided on the first printed board, The first and second bypass capacitors, the first to third lead lines, and the inductive coupler are provided on the second printed circuit board, and one end of the first lead line has a connector. Is connected to a part of the ground line on the first printed circuit board, and one end of the first bypass capacitor is connected to the first printed circuit board via the second lead line and the connector. Connected to a portion of the first ungrounded wire; One end of the second bypass capacitor is connected to a part of the second ungrounded line on the first printed circuit board via the third lead line and the connector, and the first and second It is preferable that the other end of each of the bypass capacitors is connected to the other end of the first lead line.

  In the present invention, the operating frequency of the first to fourth power line modems is preferably 10 k to 450 kHz. According to this configuration, two different power line communications can coexist using the lower frequency band.

  The watt-hour meter according to the present invention is also close to the consumer of a single-phase three-wire low-voltage distribution line composed of a ground wire extending from the transformer to the consumer, a first non-ground wire, and a second non-ground wire. A watt-hour meter for measuring power consumption of the consumer, connected to the low-voltage distribution line, and for measuring the power usage, and closer to the transformer than the weighing unit A power line modem connected to the low-voltage distribution line and a first line that is provided at a connection point of the power line modem on the low-voltage distribution line and connects the ground line and the first non-ground line of the low-voltage distribution line. A power supply line comprising: a bypass capacitor; and a second bypass capacitor provided at a connection point of the power line modem on the low-voltage distribution line and connecting the ground line of the low-voltage distribution line and the second non-ground line. The modem is connected to the weighing unit. In addition, one end is connected to the first lead line connected to the ground line by an inductive coupling method, and the other end of the first lead line is connected to the first bypass capacitor and the second lead line. And connected to the first non-grounded line via a line, and connected to the second non-grounded line via the second bypass capacitor and a third lead line. To do.

  ADVANTAGE OF THE INVENTION According to this invention, the small watt-hour meter which enables coexistence of a remote meter-reading system and a home system can be provided at low cost using the low frequency band on a common power line.

  ADVANTAGE OF THE INVENTION According to this invention, the power line communication system which can coexist both a remote meter-reading system and an in-home system using the low frequency band (10k-450kHz) on a common power line can be provided. . Moreover, according to this invention, the watt-hour meter for implement | achieving such a power line communication system can be provided.

1 is a configuration diagram of a power line communication system according to a first embodiment of the present invention. It is a block diagram of the connection of the home system between adjacent doors in 1st Embodiment. 3 is a schematic plan view showing an example of a specific configuration of the watt-hour meter 11. FIG. It is a measurement circuit diagram of a remote meter reading system (A route), (a) is a measurement circuit diagram of an example, and (b) is a measurement circuit diagram of a comparative example. It is a graph which shows the measurement result of the transmission characteristic of the PLC test signal in an Example and a comparative example. It is a measurement circuit diagram of a home system (B route), (a) is a measurement circuit diagram of an example, (b) is a measurement circuit diagram of a comparative example. It is a graph which shows the measurement result of the transmission characteristic of the PLC test signal in an Example and a comparative example. It is a measurement circuit diagram of the home system between the adjacent doors by an Example. It is a graph which shows the measurement result of the transmission characteristic of the PLC test signal in an Example. It is a measurement circuit diagram of the in-home system between adjacent doors by a comparative example. It is a graph which shows the measurement result of the transmission characteristic of the PLC test signal in a comparative example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram of a power line communication system according to a first embodiment of the present invention.

  As shown in FIG. 1, the power line communication system 1 includes a distribution board 4 connected to the end of a single-phase three-wire low-voltage distribution line 2 and a plurality of in-home wirings 2 t extending from the distribution board 4. Home appliances 7A to 7E, power line modems 10A, 10D, 10E, and 10J connected to the low-voltage distribution line 2, and a watt hour meter 11 that measures the amount of power used by consumers who use the home appliances 7A to 7E ing.

  The low voltage distribution line 2 includes three power lines 2a connected to the secondary side (low voltage side) of the pole transformer (transformer) 3 that steps down the voltage (6600V) of the high voltage distribution line to the commercial voltage (100V or 200V). , 2b, 2c. Of these power lines, the power lines 2a and 2c (red phase and black phase) connected to one end and the other end of the secondary side of the pole transformer 3 are ungrounded lines and are connected to the midpoint of the secondary side. The power line 2b (white phase) is a ground line (neutral line). The voltage between the power lines 2a and 2c (red and black phase) is 200V, and the voltage between the power lines 2a and 2b (red and white phase) and between the power lines 2c and 2b (black and white phase) is 100V.

  The power line modem 10 </ b> A (first power line modem) is connected to the low voltage distribution line 2 near the pole transformer 3. The power line modem 10A is connected to the white phase power line 2b of the low-voltage distribution line 2 by an inductive coupling method. An inductive coupler 5A is coupled to the power line 2b, and the signal line 6A connected to the signal input / output terminal of the power line modem 10A is coupled to the power line 2b via the inductive coupler 5A. The inductive coupler 5A is, for example, a toroidal core, and the power line 2b and the signal line 6A pass through the hollow portion of the toroidal core.

  The power line modem 10 </ b> A is connected to the server 9 </ b> A via a communication line installed near the pole transformer 3, for example, an optical fiber line 8. In order to facilitate connection with the optical fiber line 8, the power line modem 10 </ b> A is preferably mounted on the utility pole together with the pole transformer 3.

  A plurality of home appliances 7 </ b> A to 7 </ b> E are connected to the low-voltage distribution line 2 extending from the pole transformer 3 via the distribution board 4 and the home wiring 2 t. The home appliances 7A and 7B are devices that are connected between the ground line and one non-ground line (red and white phase) and are supplied with AC 100V power. The home appliances 7D and 7E are the ground line and the other non-ground line. It is a device connected to the ground line (black and white phase) and supplied with AC 100V power. Furthermore, the household electrical appliance 7C is a device that is connected between two ungrounded wires (red and black phase) and is supplied with AC200V power. Note that the type and number of home appliances are not particularly limited. The power consumption of these home appliances is measured by a watt hour meter 11.

  In the present embodiment, power line modems 10D and 10E (second power line modems) are incorporated in home appliances 7A and 7E, respectively. The power line modem 10D is connected to the red phase power line 2a and the white phase power line 2b of the low voltage distribution line 2 by a capacitive coupling method. That is, a pair of signal input / output terminals of the power line modem 10D are connected to the power line 2a and the power line 2b via the coupling capacitors 14a and 14b, respectively. The power line modem 10E is connected to both the black phase power line 2c and the white phase power line 2b of the low voltage distribution line 2 by a capacitive coupling method. That is, the signal input / output terminal of the power line modem 10E is connected to the power lines 2c and 2b via the coupling capacitors 14a and 14b, respectively.

  The home appliance 7A is a device having a power display function, for example, and receives meter-reading data from the watt hour meter 11, and displays (visualizes) the power usage status on the display to promote power saving. Further, the home appliance 7 </ b> A may have a function of controlling its own power usage based on the meter reading data from the watt hour meter 11. The power line modem 10D communicates with the power line modem 10J.

  The home appliance 7E is, for example, a HEMS (Home Energy Management System) server. The HEMS server is a device that manages the power usage of the other home appliances 7A to 7D in an integrated manner, obtains the power usage measured by the watt hour meter 11, and based on this acquires the power usage of each home appliance. Control individually. Short-distance wireless communication such as Zigbee (registered trademark) may be used for communication between the HEMS server and each of the home appliances 7A to 7D, or power line communication may be used. For example, power line communication can be performed between the home appliance 7A having the power line modem 10D and the HEMS server.

  In the present embodiment, the power line modem 10J (third power line modem) is incorporated in the watt hour meter 11. The watt-hour meter 11 is provided on the low-voltage distribution line 2 upstream of the weighing unit 12, the power line modem 10 </ b> J connected to the low-voltage distribution line 2, and the measurement unit 12 that actually measures the power consumption of the consumer. First and second bypass capacitors 13a and 13b. The watt hour meter 11 is connected to the low voltage distribution line 2 near the distribution board 4 and closer to the pole transformer 3 than the distribution board 4.

  One end of the power line modem 10J in the watt hour meter 11 is connected by an inductive coupling method to a lead wire 2e connected to the white phase power line 2b of the low voltage distribution line 2. The other end of the lead line 2e is connected to the red phase power line 2a via the bypass capacitor 13a and the lead line 2d, and is connected to the black phase power line 2c via the bypass capacitor 13b and the lead line 2f. An inductive coupler 5J is coupled to the lead wire 2e, and the signal line 6J connected to the signal input / output terminal of the power line modem 10J is coupled to the lead wire 2e via the inductive coupler 5J. The inductive coupler 5J is, for example, a toroidal core, and the lead wire 2e and the signal line 6B penetrate the hollow portion of the toroidal core.

  In the present embodiment, the power line modem 10J is connected to the measuring unit 12, and the metering data of the power usage by the measuring unit 12 is output to the power line modem 10J. The power line modem 10J injects a PLC (Power Line Communication) signal, which is a modulation signal of meter-reading data, into the lead-out line 2e (power line 2b) and transmits it to one of the power line modems 10A, 10D, and 10E.

  The first bypass capacitor 13a connects the red phase power line 2a and the white phase power line 2b, and the second bypass capacitor 13b connects the black phase power line 2c and the white phase power line 2b. . The first and second bypass capacitors 13a and 13b have a low impedance with respect to the operating frequency of the power line modems 10A, 10D, 10E, and 10J, and a high impedance with respect to the commercial frequency (50 Hz or 60 Hz).

  The remote meter reading system is realized by communication between the power line modem 10A and the power line modem 10J. The power line modem 10J incorporated in the watt hour meter 11 transmits meter reading data to the power line modem 10A via the power line 2b. The power line modem 10A also transmits meter reading data to the power line modem 10J via the power line 2b. Thus, the communication route (A route) between the power line modem 10A and the power line modem 10J in the watt hour meter 11 is a route for providing meter reading data of the watt hour meter 11 to the power company.

  On the other hand, the home system is realized by communication between the power line modem 10D or 10E and the power line modem 10J. The power line modem 10J incorporated in the watt hour meter 11 transmits meter reading data to the power line modems 10D and 10E via the power line 2b. On the other hand, the power line modem 10D incorporated in the home appliance 7A transmits meter reading data via the power lines 2a and 2b. The power line modem 10E incorporated in the home appliance 7E transmits meter reading data via the power lines 2c and 2b. Thus, the communication route (B route) between the power line modems 10D and 10E and the power line modem 10J in the watt hour meter 11 is a route for providing meter reading data of the watt hour meter 11 to the power consumer.

  In the present embodiment, bypass capacitors 13 a and 13 b are provided in the watt hour meter 11. The first bypass capacitor 13a is mounted on a lead wire 2d connected at one end to the red phase power line 2a, and the second bypass capacitor 13b is connected at the lead wire connected to the black phase power line 2c. It is mounted on 2f. The first and second bypass capacitors 13a and 13b have the effect of reflecting the PLC signal used in the A route to the A route side and reflecting the PLC signal used in the B route to the B route side. Attenuation can be ensured. Accordingly, a communication route (A route) configured between the power line modem 10A and the power line modem 10J and a communication route (B route) configured between the power line modem 10J and the power line modem 10D or the power line modem 10E are obtained. Since they are separated, it is possible to prevent the A-line power line communication and the B-route power line communication from interfering with each other, thereby improving communication quality.

  Furthermore, since the phase used for power line communication is changed between the A route and the B route, further attenuation of the PLC signal entering the other route from one route can be expected. The power line used in the A route and the power line used in the B route communication are different, the communication using the power line 2b (ground line) is performed in the A route, and the power lines 2a and 2c (ungrounded line) are used in the B route. Since communication is performed, communication between the A route and the B route can be prevented from interfering with each other, and communication quality can be improved.

  In the present embodiment, since the power line modem 10J in the watt hour meter 11 is commonly used for A route communication and B route communication, only one power line modem needs to be installed. The total size can be reduced.

  FIG. 2 is a configuration diagram of connection of a home system between adjacent doors in the first embodiment.

  As shown in FIG. 2, the in-home system on the in-house A side and the in-home system on the in-house B side are connected to each other via a low voltage distribution line 2. The PLC signal of A route from the power line modem 10J in the watt-hour meter 11 in the home A to the power line modem 10A (see FIG. 1) is transmitted to the home B via the power line 2b, and the power line in the watt-hour meter 11 in the home B The modem 10J is reached. At this time, since the bypass capacitors 13a and 13b in the watt-hour meter 11 in the home B reflect the PLC signal used in the A route toward the A route, interference with the communication on the B route in the home B can be prevented. . Furthermore, since the bypass capacitors 13a and 13b in the watt-hour meter 11 reflect the PLC signal of the B route used in the home system to the B route side, mutual interference of the home system between adjacent doors can be prevented.

  FIG. 3 is a schematic plan view showing an example of a specific configuration of the watt-hour meter 11.

  As shown in FIG. 3, the watt hour meter 11 includes a metering unit 12 that actually measures the power usage, and a power line modem that modulates the meter usage data of the power usage measured by the metering unit 12 and sends the data on the power line 10J, a display unit 16 that displays the meter reading data and the operation state of the watt hour meter 11, and a control unit 17 that controls the metering unit 12, the power line modem 10J, and the display unit 16. The weighing unit 12, the display unit 16, and the control unit 17 are mounted on the main printed circuit board 18A, and the power line modem 10J is mounted on the sub printed circuit board 18B.

  The sub printed circuit board 18B is mounted on the main printed circuit board 18A, and the connector 20B on the sub printed circuit board 18B is connected to the connector 20A on the main printed circuit board 18A. A broken line U indicates an overlapping position of the sub printed circuit board 18B. The power line modem 10J is connected to the control unit 17 via the connectors 20A and 20B. Thus, since the power line modem 10J is provided on a separate substrate from the metering unit 12, the power line modem 10J can be easily mounted on the watt hour meter 11.

  On one main surface (front surface) of the main printed circuit board 18A, three printed wirings 19a, 19b, and 19c are provided so as to run in parallel with each other. The printed wirings 19a, 19b, and 19c constitute a part of the three power lines 2a, 2b, and 2c of the low-voltage distribution line 2 in FIG. Specifically, the printed wiring 19a is a red phase power line 2a, the printed wiring 19b is a white power line (neutral line) 2b, and the printed wiring 19c is a black phase power line 2c. One end side of the printed wirings 19a, 19b, 19c is connected to the low voltage distribution line 2 on the pole transformer 3 side, and the other end side is connected to the low voltage distribution line 2 on the distribution board 4 side.

  The power line modem 10J is connected to the printed wiring 19e on the sub printed circuit board 18B by an inductive coupling method. The toroidal core loop constituting the inductive coupler 5J surrounds the printed wiring 19e through two openings 18h and 18h penetrating the sub printed circuit board 18B formed on both sides of the printed wiring 19e. It is installed as follows. That is, the printed wiring 19e passes through the hollow portion of the toroidal core.

  Further, it is a region of the other main surface (back surface) of the sub printed circuit board 18B sandwiched between the openings 18h and 18h, and a position overlapping the printed wiring 19b in a plan view (shown intentionally slightly shifted in FIG. 3). Are printed wirings 19J which are signal lines extending from the signal input / output terminals of the power line modem 10J, and the printed wirings 19J also penetrate through the hollow portion of the toroidal core. A broken line in the figure indicates that the printed wiring 19J is a wiring on the back surface.

  One ends of the printed wirings 19d, 19e, and 19f on the sub printed circuit board 18B corresponding to the lead lines 2d, 2e, and 2f are respectively connected to the printed wirings 19a, 19b, and 19c on the main printed circuit board 18A through the pair of connectors 20A and 20B. Are connected to each. One end of the printed wiring 19d is connected to the printed wiring 19a via the connector connectors 20A and 20B, and the other end of the printed wiring 19d is connected to the other end of the printed wiring 19e. One end of the printed wiring 19f is connected to the printed wiring 19c via the connector connectors 20A and 20B, and the other end of the printed wiring 19f is connected to the other end of the printed wiring 19e. A bypass capacitor 13a is provided on the printed wiring 19d, and a bypass capacitor 13b is provided on the printed wiring 19f.

  As described above, in the present embodiment, since the bypass capacitors 13a and 13b are provided, communication between the A route and the B route can be separated, and mutual interference can be suppressed. Therefore, it is possible to reduce the influence of household appliance noise in the home on the communication of the A route, and it is possible to prevent the interference of the PLC signal between the B routes of the adjacent doors (between the HEMS of the adjacent doors).

  In the present embodiment, since only one power line modem on the watt-hour meter side is required, the communication unit can be downsized. Further, since the PLC signal injection / extraction unit of the power line modem is provided in the lead-out line instead of the main line of the power line, the circuit configuration can be easily realized even when the metering unit and the communication unit of the watt-hour meter are separated. In particular, since the power line modem 10J is provided on the sub-printed circuit board 18B different from the main printed circuit board 18A on which the watt-hour meter (metering unit) is mounted and connected via the connectors 20A and 20B, the watt-hour meter It is possible to facilitate the implementation of a power line modem.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

  For example, in the said embodiment, although the case where the transformer connected to the one end side of the low voltage distribution line 2 was the pole top transformer 3 was mentioned as an example, this invention is not limited to the pole top transformer 3. For example, it may be a transformer installed in a substation room of an apartment house. In large housing complexes and condominiums, there are cases where high voltage distribution lines are directly drawn into the site for transformation, and a transformer is installed in one room of the building on the site. It can also be.

Example 1
The transmission characteristics of the remote meter reading system (A route) according to the example and the comparative example were evaluated. FIG. 4A is a measurement circuit diagram of the example, and FIG. 4B is a measurement circuit diagram of the comparative example.

  As shown in FIGS. 4A and 4B, an equivalent circuit of a pole transformer (impedance 0Ω (short circuit)) is provided on one end side (upstream side) of each power line 2a, 2b, 2c of the low-voltage distribution line. . A 12Ω termination resistor 25 was inserted between the red and white phases on the other end side (downstream side) of each power line 2a, 2b and 2c and between the black and white phases.

  In the measurement circuit of the embodiment shown in FIG. 4A, a signal transmission unit 31 corresponding to the power line modem 10A is provided beside the equivalent circuit of the pole transformer, and a signal reception corresponding to the power line modem 10J is adjacent to the termination resistor 25. A portion 32 is provided. In the connection of the signal transmission unit 31, the signal line 6A was connected to the power line 2b via the inductive coupler 5A, and the signal line 6A was connected to the output terminal of the network analyzer 22 via the balun 23. In connection with the signal receiving unit 32, one end of the lead wire 2e is connected to the power line 2b, the signal line 6J is connected to the lead wire 2e via the inductive coupler 5J, and the signal line 6J is connected to the network via the balun 24. The input terminal of the analyzer 22 was connected. Furthermore, the other end of the lead line 2e was connected to the power line 2a via the bypass capacitor 13a and the lead line 2d, and connected to the power line 2c via the bypass capacitor 13b and the lead line 2f.

In the measurement circuit of the comparative example shown in FIG. 4B, a signal transmission unit 31 corresponding to the power line modem 10A is provided beside the equivalent circuit of the pole transformer, and a signal reception corresponding to the power line modem 10J is adjacent to the termination resistor 25. The point which provided the part 32 is the same as the Example. In the connection of the signal transmission unit 31, signal lines 6A ₁ and 6A ₂ are connected to the power lines 2a and 2c via coupling capacitors 14a and 14b, respectively, and a network analyzer is connected to the signal lines 6A ₁ and 6A ₂ via a balun 23. 22 output terminals were connected. Similarly, the signal receiver 32 is connected to the power lines 2a and 2c through the coupling capacitors 14a and 14b, respectively, and the signal lines 6B ₁ and 6B ₂ are connected to the signal lines 6B ₁ and 6B ₂ , respectively. The input terminal of the network analyzer 22 was connected via The capacitances of the coupling capacitors 14a and 14b were both 0.47 μF.

  In the above configuration, a test signal is output from the network analyzer 22, and the test signal is superimposed on the power line. The frequency of the test signal was 50 to 450 kHz, which is the carrier frequency band of the power line modem. Then, the test signal transmitted from one end side to the other end side of the power line was received by the network analyzer 22, and the gain of the test signal was obtained.

  FIG. 5 is a graph showing the measurement results of the example (improved method) and the comparative example (conventional method). In the comparative example, the transmission characteristic of the A route, that is, the transmission characteristic of the signal from the power line modem 10A to the power line modem 10J is about −62 dB or more. On the other hand, in the example, the transmission characteristic of the A route is about −12 dB or more. From the above results, it was found that the transmission characteristics of the example were better than the comparative example.

(Example 2)
Next, the transmission characteristics of the home system (B route) according to the example and the comparative example were evaluated. FIG. 6A is a measurement circuit diagram of the example, and FIG. 6B is a measurement circuit diagram of the comparative example. Moreover, FIG. 7 is a graph which shows the measurement result of an Example and a comparative example.

  In the measurement circuit of the embodiment shown in FIG. 6A, a signal transmission unit 31 corresponding to the power line modem 10J is provided next to the termination resistor 25, and a signal corresponding to the power line modem 10E is provided at a connection point (termination position) of the termination resistor. A receiving unit 32 is provided, and a pseudo modem circuit 29 is provided beside the equivalent circuit of the pole transformer. The connection configuration of the signal transmission unit 31 is the same as the connection configuration of the signal reception unit 31 in FIG. Further, the connection configuration of the signal receiving unit 32 is a capacitive coupling method similar to that of the signal transmitting unit 31 in FIG. 4B, and is connected to the power lines 2b and 2c using the coupling capacitors 14a and 14b, respectively.

  In the measurement circuit of the comparative example shown in FIG. 6B, a signal transmission unit 31 corresponding to the power line modem 10J is provided next to the termination resistor 25, and a signal corresponding to the power line modem 10E is connected to the connection point (termination position) of the termination resistor. A receiving unit 32 is provided. The connection configuration of the signal transmission unit 31 and the signal reception unit 32 is a capacitive coupling method similar to the signal transmission unit 31 in FIG. 4B, and the signal transmission unit 31 is connected to the power lines 2a and 2c using the coupling capacitors 14a and 14b. The signal receiving unit 32 is connected to the power lines 2b and 2c.

  FIG. 7 is a graph showing the measurement results of the example (improved method) and the comparative example (conventional method). In the comparative example, the transmission characteristic of the B route, that is, the transmission characteristic of the signal from the power line modem 10J in the watt hour meter 11 to the power line modem 10E of the home electrical appliance 7E is about −27 dB or more. On the other hand, in the example, the transmission characteristic of the B route is about −24 dB. From the above results, it was found that the transmission characteristics of the B route according to the example and the comparative example are generally good.

(Example 3)
Next, the transmission characteristic between the adjacent doors of the home system by an Example and a comparative example was evaluated. 8A to 8C are measurement circuit diagrams of the example, and FIG. 9 is a graph showing measurement results of the example. Moreover, Fig.10 (a)-(c) is a measurement circuit diagram of a comparative example, and FIG. 11 is a graph which shows the measurement result of a comparative example.

  The measurement circuit diagram of the embodiment shown in FIGS. 8A to 8C is configured such that one end side of each of the power lines 2a, 2b, and 2c of the low-voltage distribution line is a customer premises A, and the other end side is a customer premises B, A 12Ω termination resistor 25 was inserted between the red and white phases at both ends of each power line 2a, 2b and 2c and between the black and white phases. 8A, a signal transmission unit 31 corresponding to the power line modem 10J in the watt hour meter 11 on the home A side is provided, and a connection point (termination position) of the termination resistor 25 on the other end side of each power line is provided. Provided a signal receiving unit 32 corresponding to the power line modem 10E in the home appliance 7E in the house B. Further, a pseudo modem circuit 29 corresponding to the power line modem 10J in the watt-hour meter 11 on the home B side is provided between the signal transmission unit 31 and the signal reception unit 32. The connection configuration of the signal transmission unit 31 is an inductive coupling method, similar to the signal reception unit 32 in FIG. The connection configuration of the signal receiving unit 32 is a capacitive coupling method similar to that of the signal receiving unit 32 in FIG. 4B, and the signal transmitting unit 31 is connected to the power lines 2a, 2b, and 2c using the coupling capacitors 14a and 14b. The signal receiving unit 32 is connected to the power lines 2b and 2c.

  8B and 8C, a signal transmission unit 31 corresponding to the power line modem 10E in the home appliance 7E in the home A is provided at the connection point (termination position) of the termination resistor 25 on one end side of each power line. The signal receiving unit 32 corresponding to the power line modem 10E in the home appliance 7E in the house B is provided at the connection point (terminal position) of the terminal resistor 25 on the other end side. In particular, in FIG. 8B, both the signal transmitting unit 31 and the signal receiving unit 32 are connected in a black and white phase, and in FIG. 8C, the signal transmitting unit 31 is connected in a red and white phase, and the signal receiving unit 32 is connected. The connection was black and white.

  As shown in FIG. 9, the signal transmission characteristic in the measurement circuit of FIG. 8A is about −28 dB or more. Further, the signal transmission characteristics in the measurement circuits of FIGS. 8B and 8C were −40 dB or more, and it was found that signal interference between adjacent doors was suppressed.

  In the measurement circuit diagram of the comparative example shown in FIGS. 10A to 10C, one end side of each of the power lines 2a, 2b, and 2c of the low-voltage distribution line is the customer premises A, and the other end side is the customer premises B, A 12Ω termination resistor 25 was inserted between the red and white phases at both ends of each power line 2a, 2b and 2c and between the black and white phases. 10A, a signal transmission unit 31 corresponding to the power line modem 10J in the watt hour meter 11 on the home A side is provided, and a connection point (termination position) of the termination resistor 25 on one end side of each power line is provided. A signal receiving unit 32 corresponding to the power line modem 10E in the home appliance of the house B is provided. The connection configuration of the signal transmission unit 31 and the signal reception unit 32 is a capacitive coupling method similar to the signal transmission unit 31 in FIG. 4B, and the signal transmission unit 31 is connected to the power lines 2a and 2c using the coupling capacitors 14a and 14b. The signal receiving unit 32 is connected to the power lines 2b and 2c.

  10 (b) and 10 (c), a signal transmission unit 31 corresponding to the power line modem 10E in the home appliance in the house A is provided at the connection point (termination position) of the termination resistor on one end side of each power line. A signal receiving unit 32 corresponding to the power line modem 10E in the home appliance B in the house B is provided at a connection point (terminal position) of the terminal resistor 25 on the end side. In particular, in FIG. 10B, both the signal transmitting unit 31 and the signal receiving unit 32 are connected in black and white phase, and in FIG. 10C, the signal transmitting unit 31 is connected in red and white phase, and the signal receiving unit 32 is connected. The connection was black and white.

  As shown in FIG. 11, the signal transmission characteristic in FIG. 10A is about −28 dB or more. Further, the signal transmission characteristic in FIG. 10B was −22 dB, and it was found that signal interference occurred between adjacent doors. Furthermore, the signal transmission characteristic in FIG. 10C was −52 dB, and it was found that there was no signal interference between adjacent doors when the phases were different between the transmission side and the reception side.

1 Power Line Communication System 2 Low Voltage Distribution Line 2a Power Line (First Ungrounded Line)
2b Power line (ground line, neutral line)
2c Power line (second ungrounded line)
2t terminal wiring 3 poster transformer 4 minutes board 5A inductive coupler 5J inductive coupler 6A, 6B signal lines _6A 1, 6A ₂ signal lines _6B 1, 6B ₂ signal line 6J signal line 7A~7E Appliances 8 optical fiber line 9A Server 10A Power line modem (first power line modem)
10D, 10E power line modem (second power line modem)
10J power line modem (third power line modem)
DESCRIPTION OF SYMBOLS 11 Electricity meter 12 Metering part 13a, 13b Bypass capacitor 14a, 14b Coupling capacitor 16 Display part 17 Control part 18A Main printed circuit board 18B Sub printed circuit board 18h Sub printed circuit board opening 19a-19f Printed wiring 20A, 20B Connector 22 Network analyzer 23 balun 24 balun 25 termination resistor 29 pseudo-modem circuit 31 signal transmission unit 32 signal reception unit

Claims (7)

A single-phase three-wire low-voltage distribution line composed of a ground wire extending from the transformer to the consumer, a first non-ground wire and a second non-ground wire, and power consumption of the consumer connected to the low-voltage distribution wire A power line communication system installed in a distribution facility having a watt-hour meter for measuring the amount,
A first power line modem connected to the low voltage distribution line near the transformer;
A second power line modem connected to the low voltage distribution line closer to the consumer than the electricity meter;
A third power line modem connected to the low voltage distribution line closer to the customer than a connection point of the first power line modem and performing power line communication with the first and second power line modems;
A first bypass capacitor provided at a connection point of the third power line modem on the low-voltage distribution line and connecting the ground line of the low-voltage distribution line and the first non-ground line;
A second bypass capacitor provided at a connection point of the third power line modem on the low-voltage distribution line and connecting the ground line of the low-voltage distribution line and the second non-ground line;
The first power line modem is connected to the ground line of the low-voltage distribution line by an inductive coupling method,
The second power line modem is connected to at least two of the ground line, the first non-ground line, and the second non-ground line of the low-voltage distribution line by a capacitive coupling method,
The third power line modem is connected by an inductive coupling method to a first lead wire having one end connected to the ground line,
The other end of the first lead line is connected to the first non-ground line via the first bypass capacitor and the second lead line, and the second bypass capacitor and the third lead line are connected to the first non-ground line. A power line communication system, wherein the power line communication system is connected to the second ungrounded line via a lead wire.   The power line communication system according to claim 1, wherein the third power line modem is provided in the watt-hour meter. Further comprising a distribution board for branching the low-voltage distribution line closer to the consumer than the electricity meter,
The power line communication system according to claim 1 or 2, wherein the second power line modem is connected to a home wiring branched from the distribution board.   The said 3rd power line modem transmits the meter-reading data of the said power consumption measured by the said watt-hour meter to the said 1st or 2nd power line modem. Power line communication system. The watt-hour meter includes a metering unit that actually measures the power consumption, a first printed circuit board on which the metering unit is mounted, and a second printed circuit board on which the third power line modem is mounted. Including
A part of the ground line, a part of the first non-ground line, and a part of the second non-ground line are provided on the first printed circuit board;
The first and second bypass capacitors, the first to third lead wires, and the inductive coupler are provided on the second printed circuit board,
One end of the first lead line is connected to a part of the ground line on the first printed circuit board via a connector,
One end of the first bypass capacitor is connected to a part of the first ungrounded line on the first printed circuit board via the second lead line and the connector,
One end of the second bypass capacitor is connected to a part of the second ungrounded line on the first printed circuit board via the third lead line and the connector,
The power line communication system according to claim 4, wherein the other end of each of the first and second bypass capacitors is connected to the other end of the first lead line.   The power line communication system according to any one of claims 1 to 5, wherein a use frequency of the first to fourth power line modems is 10k to 450kHz. A single-phase three-wire low-voltage distribution line composed of a ground wire extending from the transformer to the customer, a first non-ground wire, and a second non-ground wire is installed near the customer, and uses the customer's power A watt-hour meter for measuring the quantity,
A measuring unit connected to the low-voltage distribution line and measuring the power consumption;
A power line modem connected to the low voltage distribution line closer to the transformer than the metering unit;
A first bypass capacitor provided at a connection point of the power line modem on the low-voltage distribution line, and connecting the ground line and the first non-ground line of the low-voltage distribution line;
A second bypass capacitor provided at a connection point of the power line modem on the low-voltage distribution line, and connecting the ground line of the low-voltage distribution line and the second non-ground line;
The power line modem is connected to the weighing unit and connected to the first lead wire connected at one end to the ground line by an inductive coupling method.
The other end of the first lead line is connected to the first non-ground line via the first bypass capacitor and the second lead line, and the second bypass capacitor and the third lead line are connected to the first non-ground line. The watt hour meter is connected to the second non-grounded wire via a lead wire.