JP7804274B2 - Power line communication system and cubicle - Google Patents

Description

This disclosure relates to power line communication systems and cubicles.

Power line communication (PLC), which transmits signals by superimposing them on power lines, has been known for some time. Patent Document 1 discloses a power line communication device consisting of one or more communication devices connected to a power line and capable of communicating via the power line. Patent Document 1 discloses a printer main body that connects to a power line and performs power line communication, and a PC main body that performs power line communication with the printer main body via the power line. The printer main body is connected to a power line communication unit that performs power line communication with the PC main body, and sends and receives signals via the power line communication unit and control lines. The PC main body is equipped with a PCI board. The power line communication unit and PCI board each have a driver receiver that sends and receives power line communication signals.

Japanese Patent Application Laid-Open No. 2004-165950

In power line communications, when a signal is transmitted from a transmitter to a receiver, some of the signal may be transmitted from the transmitter to the power supply side, opposite the receiver, making it difficult for the signal to be transmitted from the transmitter to the receiver. For example, with the configuration described in Patent Document 1, there is a risk that a signal output from a PC to a printer may not be transmitted properly to the printer. In this case, it becomes difficult for the signal from the transmitter to reach the receiver, making it impossible to ensure proper communication quality.

The purpose of this disclosure is to provide a power line communication system and cubicle that can ensure appropriate communication quality in narrowband power line communication.

A power line communication system according to one aspect of the present disclosure includes a transmitter electrically connected to a voltage-changing transformer by a first electrical circuit and transmitting a signal in narrowband power line communication; a receiver electrically connected to the transmitter and receiving the signal; and a promoter provided directly below the transformer on the first electrical circuit and promoting the flow of the signal from the transmitter to the receiver.

In this power line communication system, the transformer and the transmitter are electrically connected, and the transmitter and receiver are electrically connected. Because the promoter is located directly below the transformer, it can promote the flow of signals from the transmitter to the receiver in the first electrical path upstream of the transmitter. This allows the receiver to properly acquire signals from the transmitter. Therefore, this power line communication system can ensure appropriate communication quality.

In one embodiment of the power line communication system, the receiving unit is electrically connected to the transmitting unit via a second electrical circuit, and the promoting unit may adjust the impedance of the first electrical circuit so that it is greater than the impedance of the second electrical circuit. In this case, adjustment by the promoting unit causes the impedance of the first electrical circuit to be greater than the impedance of the second electrical circuit, making it easier for signals from the transmitting unit to flow through the second electrical circuit than through the first electrical circuit. Therefore, the promoting unit can promote the flow of signals from the transmitting unit to the receiving unit, ensuring appropriate communication quality.

In one embodiment, the power line communication system further includes a distribution board that houses a main breaker installed in the first electrical circuit between the transformer and the transmitter, and the facilitating unit may be installed outside the distribution board, in the first electrical circuit between the transformer and the distribution board. In this case, the facilitating unit is installed outside the distribution board, directly below the transformer. This power line communication system reduces the labor required to install a facilitating unit for each distribution board, and can simultaneously promote the flow of signals to each distribution board.

In one embodiment of the power line communication system, the signal frequency may be greater than or equal to 10 kHz and less than or equal to 450 kHz.

In one embodiment of the power line communication system, the facilitating unit may be provided in at least one of the three-phase first electrical circuits. In this case, for example, if the facilitating unit is provided in the electrical circuit to which at least the transmitting unit and receiving unit are connected, it can facilitate the flow of signals. Therefore, this power line communication system can minimize the number of facilitating units installed, making installation and maintenance of the facilitating units easier.

According to another aspect of the present disclosure, a cubicle is provided. The cubicle is connected to a power line communication system that includes a transmitter that transmits signals in narrowband power line communication and a receiver that receives the signals. The cubicle also includes a transformer that is electrically connected to the power line communication system by a first electrical path and changes voltage, and a promoter that is provided directly below the transformer and promotes signal flow to the opposite side of the transformer.

In this cubicle, the transformer and power line communication system are electrically connected by a first electrical path. Because the acceleration unit is installed directly below the transformer, it can accelerate the flow of signals from the transmitting unit to the receiving unit in the cubicle upstream of the transmitting unit. This allows the receiving unit to properly acquire signals from the transmitting unit. This allows this cubicle to ensure appropriate communication quality. Furthermore, for example, there is no need to install an acceleration unit in each distribution board connected to the cubicle. The acceleration unit installed in the cubicle can collectively accelerate the flow of signals in the electrical paths downstream of the cubicle.

In one embodiment of the cubicle, the cubicle has multiple breakers electrically connected to the transformer by a first electrical circuit and installed between the transformer and the transmitting unit, and the accelerating unit may be installed between the transformer and the breaker. In this case, installing the accelerating unit between the transformer and the breaker can reduce the labor required to install and maintain the accelerating unit compared to installing and maintaining the accelerating unit downstream of each breaker.

The power line communication system and cubicle disclosed herein can ensure appropriate communication quality in narrowband power line communications.

1 is a block diagram illustrating a power line communication system according to an embodiment. FIG. 2(a) is a block diagram of the detection slave unit, FIG. 2(b) is a block diagram of the receiving unit, and FIG. 2(c) is a block diagram of the transmitting unit. 1 is a schematic configuration diagram illustrating an example of a power line communication system and a cubicle according to an embodiment. FIG. 2 is a schematic diagram illustrating the configuration of a distribution board. FIG. 1 is a schematic diagram illustrating a configuration of a cubicle according to an embodiment. FIG. 10 is a schematic diagram showing the configuration of a cubicle according to a modified example. FIG. 10 is a schematic configuration diagram showing a power line communication system according to a modified example. 8A is a circuit diagram of a power line communication system according to a comparative example before a transformer and a facilitating unit are installed, and FIG. 8B is a graph of experimental results showing a signal spectrum at a receiving unit before the transformer and the facilitating unit are installed. 9A is a circuit diagram of a power line communication system according to a comparative example after a transformer is installed but before a facilitating unit is installed, and FIG. 9B is a graph of experimental results showing a signal spectrum at a receiving unit after a transformer is installed but before a facilitating unit is installed. 10A is a circuit diagram of the power line communication system according to the embodiment after the transformer and the acceleration unit are installed, and FIG. 10B is a graph of experimental results showing the signal spectrum at the receiving unit after the transformer and the acceleration unit are installed.

Embodiments of the present disclosure will now be described with reference to the drawings. In the following description, identical or equivalent elements will be designated by the same reference numerals, and redundant explanations will not be repeated. The dimensional proportions of the drawings do not necessarily match those in the description. The terms "upper," "lower," "left," and "right" are used for convenience and are based on the state shown in the illustrations.

FIG. 1 is a block diagram illustrating a power line communication system 100 according to an embodiment of the present invention. As shown in FIG. 1, the power line communication system 100 transmits information between devices using power line communication (PLC), which superimposes signals onto power lines. Power line communication is a communication method for transmitting and receiving communication signals using power lines, for example, by superimposing a communication signal at a frequency different from the commercial frequency onto a commercial frequency power waveform and transmitting it, and then separating and receiving the communication signal at the different frequency from the power waveform. Note that power line communication may be subject to the Radio Law depending on the frequency band. However, the power line communication system 100 according to this embodiment is capable of performing narrowband power line communication (low-speed PLC), which transmits signals in the frequency band of 10 kHz to 450 kHz by superimposing them onto power lines. The power line communication system 100 uses narrowband power line communication to enable indoor and outdoor use and to achieve a certain level of data transfer capacity. Hereinafter, signals transmitted via narrowband power line communications will be simply referred to as "signals." Furthermore, when narrowband power line communications are used, the modulation method is not particularly limited; either OFDM or DCSK may be used.

The power line communication system 100 includes a detector 1, a detection slave unit 2, a controlled facility 3, a receiver 4, and a transmitter 6. For example, the power line communication system 100 may be applied to a building BD1 having multiple floors F1 to F3 (see Figure 3).

In the power line communication system 100, the detector 1 and the detector slave unit 2 are connected by wiring W1. The detector slave unit 2 and the transmitter unit 6 are connected by power line W2. The controlled equipment 3 and the receiver unit 4 are connected by wiring W3. The receiver unit 4 and the transmitter unit 6 are connected by power line W4. The main purpose of the power line is to supply commercial frequency AC power, and it serves as the transmission path for power line communication. Specifically, power line communication takes place between the detector slave unit 2 and the receiver unit 4 and the transmitter unit 6. Power line communication takes place between the detector 1 and the detector slave unit 2, and between the controlled equipment 3 and the receiver unit 4. In power line communication, communication signals can not only be superimposed on AC power distribution such as AC 100V or AC 200V, but communication signals can also be superimposed on DC power distribution in the same way as AC. If the detector 1 is, for example, a motion sensor or an illuminance meter, the signal from the detector 1 may first pass through the transmitter 6 and then, depending on the decision of the transmitter 6, be transmitted over the power line to the receiver 4. However, depending on the program of the transmitter 6, the detector slave 2 may also be able to use power line communication to send commands to the receiver 4 without passing through the transmitter 6.

Detector 1 is a device that detects various types of information and is composed of measuring instruments, sensors, etc. Examples of detector 1 include a motion sensor that detects the presence of a person, a light meter that detects the brightness of a room, and an ammeter that detects current values. Detector 1 outputs the detected information to detector slave unit 2 via wiring W1. Note that detector 1 is not limited to the above-mentioned devices, and other measuring instruments and sensors may also be used. For example, detector 1 may be a measuring instrument that monitors the amount of power generated by renewable energy sources such as solar cells. Detector 1 may also be a battery remaining capacity data output unit installed in a power controller for a fixed storage battery or an on-board storage battery. Detector 1 may also be a carbon dioxide detector, carbon monoxide detector, dust detector, etc.

The detector sub-unit 2 is a sub-unit provided for the detector 1. The detector sub-unit 2 converts the detection information received from the detector 1 into a power line communication signal and outputs it to the transmitter 6 via the power line W2. The detector sub-unit 2 is provided in a one-to-one correspondence with each detector 1. For example, if there are multiple detectors 1 on a floor, one detector sub-unit 2 is provided for each detector 1. For example, a dedicated detector sub-unit 2 is provided for an ammeter, a dedicated detector sub-unit 2 is provided for a motion sensor, and a dedicated detector sub-unit 2 is provided for a luminance meter. If there are multiple motion sensors, one dedicated detector sub-unit 2 is provided for each motion sensor. The detector sub-unit 2 is provided in close proximity to the target detector 1. The detector sub-unit 2 is provided on the power line connected to the target detector 1, thereby establishing a physical one-to-one relationship with the target detector 1. The detector sub-unit 2 and the detector 1 may be constructed as a single device. In this case, one device contains a unit that functions as a detector slave unit 2 and a unit that functions as a detector 1. The two are connected by wiring W1 within the device. The wiring W1 that connects the detector 1 and the detector slave unit 2 is composed of a signal line. Note that the detector slave units 2 and the detector 1 do not necessarily have to be in a one-to-one relationship; for example, a configuration in which information is sent from multiple detectors 1 to one detector slave unit 2 may be used.

Referring to Figure 2(a), the detailed block configuration of the detection slave unit 2 will be described. Figure 2(a) is a block configuration diagram of the detection slave unit. The detection slave unit 2 comprises a communication unit 11, a processing unit 12, and a memory unit 13. The communication unit 11 is a unit that communicates with the transmitter 6 and the detector 1. The communication unit 11 has a circuit that receives detection information from the detector 1. The communication unit 11 also has a circuit that converts the detection information from the detector 1 into a power line communication signal for the transmitter 6. The processing unit 12 is a unit that controls the operation of the entire detection slave unit 2. The processing unit 12 is configured to include a microprocessor and its peripheral circuits, etc.

The memory unit 13 is a unit that stores programs and information necessary for the operation of the detection slave unit 2. The memory unit 13 is configured with a non-volatile memory element such as a ROM (Read Only Memory), a rewritable non-volatile memory element such as an EEPROM (Electrically Erasable Programmable Read Only Memory), and a volatile memory element that serves as working memory, such as a RAM (Random Access Memory). For example, the memory unit 13 stores an address indicating the location of the detection slave unit 2 within building BD1.

The controlled equipment 3 shown in FIG. 1 is equipment that is subject to control by the power line communication system 100. Examples of the controlled equipment 3 include lighting (such as LED lighting) that can adjust the illuminance in a room, air conditioning that adjusts the temperature in a room, or a storage battery that adjusts the discharge and charge. The controlled equipment 3 receives control information from the receiver 4 via wiring W3. Note that the controlled equipment 3 is not limited to the above-mentioned devices, and other equipment may also be used.

The receiver 4 is a slave unit provided for the controlled equipment 3. The receiver 4 is electrically connected to the transmitter 6 and receives signals. The receiver 4 converts the control information received from the transmitter 6 via power line communication signals into a signal that can be processed by the controlled equipment 3 and outputs it to the controlled equipment 3 via wiring W3. The receiver 4 is provided in a one-to-one correspondence with each controlled equipment 3. For example, if there are multiple controlled equipment 3 on a floor, one receiver 4 is provided for each controlled equipment 3. In the example shown in Figure 3, one dedicated receiver 4 is provided for each of the multiple lights. The receiver 4 is provided in a location close to the target controlled equipment 3. The receiver 4 is provided on the power line connected to the target controlled equipment 3, thereby establishing a physical one-to-one relationship with the target controlled equipment 3. The receiver 4 and the controlled equipment 3 may be constructed as a single device. For example, an LED light with a slave unit may be used. In this case, a single device contains a unit that functions as the receiver 4 and a unit that functions as the controlled equipment 3. The two are connected by wiring W3 within the device. The receiver 4 may be installed on the same power line as the target controlled equipment, in which case the wiring W3 is made up of a power line. Alternatively, the receiver 4 may be connected to a power line separate from the target controlled equipment, in which case the wiring W3 is made up of a signal line. Note that the receiver 4 and the controlled equipment 3 do not necessarily have to have a one-to-one relationship; for example, a configuration may be adopted in which multiple controlled equipment 3 receive control information from a single receiver 4.

The receiving unit 4 adjusts the output strength of the controlled equipment 3 based on the control information from the transmitting unit 6. For example, the receiving unit 4 can generate a command signal for lighting to adjust the intensity of the lighting. The receiving unit 4 can generate a command signal for air conditioning to adjust the intensity of the air conditioning output.

Referring to Figure 2(b), the detailed block configuration of the receiver 4 will be described. Figure 2(b) is a block configuration diagram of the receiver. The receiver 4 includes a communication unit 14, a processing unit 16, and a memory unit 17. The communication unit 14 is a unit that communicates with the transmitter 6 and the controlled equipment 3. The communication unit 14 has a circuit that receives control information via power line communication signals from the transmitter 6. The communication unit 14 also has a circuit that converts the power line communication signals from the transmitter 6 into signals that can be processed by the controlled equipment 3. The processing unit 16 is a unit that controls the operation of the receiver 4 as a whole. The processing unit 16 is configured with a microprocessor and its peripheral circuits, etc. The memory unit 17 is a unit that stores programs and information required for the operation of the receiver 4. The memory unit 17 may include memory elements similar to those exemplified for the memory unit 13. For example, the memory unit 17 stores an address indicating the location of the receiver 4 within building BD1.

The transmitter 6 shown in FIG. 1 is a device that receives detection information from the detector 2 and transmits control information (control signals) to the receiver 4 based on the detection information. The transmitter 6 is a parent device for the detector 2 and the receiver 4. The transmitter 6 receives detection information in the form of power line communication signals from the detector 2 via power line W2. The transmitter 6 transmits signals in narrowband power line communication. The transmitter 6 outputs control information in the form of power line communication signals to the receiver 4 via power line W4. The transmitter 6 calculates control information for each controlled facility 3 based on at least one of preset settings and the detection information detected by the detector 1.

Referring to Figure 2(c), the detailed block configuration of the transmitter unit 6 will be described. Figure 2(c) is a block configuration diagram of the transmitter unit. The transmitter unit 6 includes a communication unit 21, a processing unit 22, and a memory unit 23. The communication unit 21 is a unit that communicates with the detector unit 2 and the receiver unit 4. The communication unit 21 has circuits that perform power line communication with the detector unit 2 and the receiver unit 4. The communication unit 21 also has circuits that perform remote communication with external communication devices using the cloud. That is, the communication unit 21 of the transmitter unit 6 includes a PLC communication unit that handles power line communication between the detector unit 2 and the receiver unit 4, and a wireless communication unit such as LTE that handles network communication with the cloud. The processing unit 22 is a unit that controls the overall operation of the transmitter unit 6. The processing unit 22 is configured with a microprocessor and its peripheral circuits, etc. The processing unit 22 calculates control information for controlling the ON/OFF switching of each light and air conditioning unit, adjustment of output strength, etc.

The memory unit 23 is a unit that stores programs and information necessary for the operation of the transmitter unit 6. The memory unit 23 may include memory elements similar to those exemplified for the memory unit 13. For example, the memory unit 23 stores addresses indicating the locations of the transmitter unit 6, each detection slave unit 2, and each receiver unit 4 within the building BD1, linked to one another.

Here, the transmitter 6 shown in FIG. 1 is installed in a power distribution facility 50 that serves as the base point of the electrical path to the multiple receivers 4 and detectors 2 within the control range of the transmitter 6. The distribution facility 50 distributes and supplies power to the multiple receivers 4 and detectors 2 that exist within the control range of the transmitter 6. The distribution facility 50 has a power supply unit 51 that supplies power to the multiple receivers 4 and detectors 2. The power supply unit 51 of the distribution facility 50 corresponds to the power supply unit that serves as the base point of the electrical path to the multiple receivers 4 and detectors 2 within the control range of the transmitter 6. The transmitter 6 is provided for the power supply unit 51. The transmitter 6 is provided closer to the power supply unit 51 than the detectors 2 and receivers 4. Such distribution facility 50 is, for example, a distribution board provided for building BD1. Another example of such a power supply unit 51 is the main breaker of the distribution board. The origin of the electrical circuit is the most upstream point in the flow of power in the power line wiring network containing multiple receivers 4 and detectors 2 within the control range. In other words, even if another distribution board is located midway in the wiring network, that distribution board does not qualify as the origin of the electrical circuit.

When the transmitter 6 is installed in the power distribution equipment 50, it means that the transmitter 6 is incorporated into the power line wiring structure of the power distribution equipment 50. Furthermore, when the transmitter 6 is provided in the power supply unit 51, it means that the transmitter 6 is electrically connected to the power line drawn from the power supply unit 51. If the power distribution equipment 50 has multiple branched power lines drawn from the housing to the outside, the transmitter 6 is connected to each power line in a manner that allows the power line communication signal to be superimposed on each branched power line. When such an electrical connection relationship is established, the location of the transmitter unit 6's transmitter body is not particularly limited. Specifically, the transmitter unit 6's transmitter body may be located inside the housing of the power distribution equipment 50 (e.g., the housing of the distribution board 10 described below), and the transmitter 6 may be connected to the wiring structure inside the housing of the power distribution equipment 50. Alternatively, the transmitter unit 6 may be located outside the housing of the power distribution equipment 50, and the transmitter unit 6 may be connected to the wiring structure inside the housing of the power distribution equipment 50. In this case, the transmitter unit 6 may be attached to the outside of a door or side of the power distribution equipment 50, and wiring may be inserted through a hole formed in the housing and connected to the wiring structure inside the housing of the power distribution equipment 50.

Next, an example of a power line communication system 100 will be described with reference to FIG. 3. FIG. 3 is a schematic configuration diagram showing an example of a power line communication system and a cubicle according to one embodiment. FIG. 3 shows an example in which the power line communication system 100 is adopted for an equipment system 101 in a building BD1 having multiple floors F1 to F3. Note that the detector 1 and the detector sub-unit 2 are omitted from FIG. 3. The building BD1 to which the power line communication system 100 is applied is, for example, an apartment building, an office, a store, a factory, a hospital, or other facility. The power line communication system 100 includes a receiving unit 4 and a transmitting unit 6. The power line communication system 100 further includes a promoting unit 33. The power line communication system 100 further includes a power source 7, distribution boards 10A, 10B, and 10C, and a cubicle 20. The power source 7 is a source of high-voltage current, such as a power plant. The equipment system 101 shown in FIG. 3 includes a cubicle 20 outside the building BD1. The equipment system 101 also includes distribution boards 10A, 10B, and 10C on each of the floors F1, F2, and F3.

Cubicle 20 is connected to a transmitter 6 that transmits narrowband power line communication signals and a receiver 4 that receives the signals via power line W7. Cubicle 20 is a facility that houses equipment that converts high voltage from the power plant into voltage usable within the facility. Cubicle 20 is composed of a transformer 31 that converts voltage, multiple (three in this case) breakers 32 that cut off overcurrent, an acceleration unit 33 installed between the transformer 31 and the multiple breakers 32, and other equipment. Transformer 31 is connected to power line W5, through which high-voltage current from power source 7 flows. Furthermore, within the cubicle 20 housing, transformer 31 is connected to one acceleration unit 33 and three breakers 32 via power lines W6. The three power lines W6 connected to the three breakers 32 are each pulled out of the cubicle 20 housing, extended into building BD1, and connected to distribution boards 10A, 10B, and 10C on each floor. The breaker 32 for the first floor is connected to the distribution board 10A on floor F1 via power line W7. The breaker 32 for the second floor is connected to the distribution board 10B on floor F2 via power line W7. The breaker 32 for the third floor is connected to the distribution board 10C on floor F3 via power line W7. The transformer 31 is electrically connected to the transmitter 6 via power line W6 and power line W7 (an example of a first electrical circuit).

Distribution boards 10A, 10B, and 10C are electrical equipment that distribute power transmitted via power line W7 to load circuits installed within the floor. Distribution boards 10A, 10B, and 10C have a wiring structure in which a collection of circuit breakers, earth leakage circuit breakers, and other devices are installed internally. Distribution board 10A on the first floor distributes power by branching it into multiple (here, two) power lines W8. Multiple receivers 4 and controlled equipment 3 (lighting in Figure 3) are connected to each power line W8. Note that some power lines W8 may be connected to load equipment that does not have a receiver 4. Levels F2 and F3 have a wiring structure for power lines W8, receivers 4, controlled equipment 3, and load equipment similar to that of level F1.

In the example shown in FIG. 3, the transmitter 6 has a control range that includes the receiver 4 installed on a specific floor (here, floor F1) of building BD1. Here, the distribution board 10A for floor F1 of building BD1 is the origin of the electrical circuit. That is, the distribution board 10A corresponds to the power distribution equipment 50 that is the origin of the electrical circuit, and the main breaker 52 installed on the distribution board 10A corresponds to the power supply unit 51 that is the origin of the electrical circuit. Therefore, the transmitter 6 is installed in the power supply unit 51 that is the origin of the electrical circuit. The transmitter 6 is installed, for example, downstream of the main breaker 52. Here, downstream refers to the side of the power line W8 that is connected to the controlled equipment 3 to which power is supplied, as viewed from the power line W5 close to the power source 7. As described above, the transmitter 6 is electrically connected to the transformer 31 of the cubicle 20 via the power lines W6 and W7 (an example of a first electrical circuit). In addition, the receiver 4 and the controlled equipment 3 are electrically connected to the transmitter 6 and the power line W8 (an example of a second electrical path).

Next, the internal configuration of distribution board 10A will be described with reference to Figure 4. As shown in Figure 4, distribution board 10A is provided with a main breaker 52, branch breakers 53A and 53B, and a transmitter 6. Figure 4 shows the structure for controlling lighting as the controlled equipment 3, among the components of distribution board 10A. Distribution boards 10B and 10C have the same configuration as distribution board 10A.

The main breaker 52 supplies power to the branch breakers 53A and 53B. The main breaker 52 also monitors the current value and cuts off the power supply when the current value exceeds a predetermined value. The main breaker 52 is a single-phase, three-wire breaker, with power line W20A connected to the L1-phase terminal, power line W20B connected to the L2-phase terminal, and power line W20C connected to the N-phase terminal on the ground side. The branch breaker 53A is connected to the L1-phase power line W20A and the N-phase power line W20C. The branch breaker 53B is connected to the L2-phase power line W20B and the N-phase power line W20C. The branch breaker 53A supplies power to each receiver 4 and controlled equipment 3 connected to power line W8A in the hierarchy F1 (see Figure 3). Branch breaker 53B supplies power to each receiver 4 and controlled equipment 3 connected to power line W8B within floor F1 (see Figure 3). As a result, main breaker 52 supplies power to the receiver 4 and controlled equipment 3 via three power lines W20A, W20B, and W20C.

In contrast, the transmitter 6 is provided in the main breaker 52 by being connected to the power lines W20B and W20C associated with the "L2 phase-N phase" combination (first combination) in the main breaker 52. Specifically, the transmitter main body 25 of the transmitter 6 is connected to the L2 phase power line W20B via the electric wire W30, and to the N phase power line W20C via the electric wire W31. This allows the signal from the transmitter 6 to pass through the power lines W20B and W20C associated with the "L2 phase-N phase" combination.

The configuration and function of the facilitating unit 33 provided within the cubicle 20 shown in FIG. 3 will now be described. The facilitating unit 33 is, for example, a ferrite core or a filter. The facilitating unit 33 according to this embodiment has two ferrite cores. The facilitating unit 33 is provided directly below the transformer 31 on the power line W6. The facilitating unit 33 being provided directly below the transformer 31 means that the facilitating unit 33 is provided on the power line between the transformer 31 and the transmitting unit 6, and that there is no configuration that increases the impedance by more than a predetermined value in the power line connecting the transformer 31 and the facilitating unit 33. The predetermined value is, for example, 0.01 Ω. The predetermined value may be between 0.01 Ω and 0.1 Ω. The predetermined value is not limited to the impedance value described above. The facilitating unit 33 being provided directly below the transformer 31 may mean, for example, that there is no electrically intervening configuration in the power line connecting the transformer 31 and the facilitating unit 33.

The accelerating unit 33 is provided outside the distribution boards 10A, 10B, and 10C, and is provided in the electrical path (either the power line W6 or the power line W7) between the transformer 31 and the distribution boards 10A, 10B, and 10C. For example, the accelerating unit 33 is provided on the power line W6 between the transformer 31 and the breaker 32. Specifically, the accelerating unit 33 may be disposed inside the housing of the cubicle 20, and the accelerating unit 33 may be connected to the wiring structure (power line W6) inside the housing of the cubicle 20. Alternatively, the accelerating unit 33 may be disposed outside the housing of the cubicle 20, and the accelerating unit 33 may be connected to the wiring structure (power line W6) inside the housing of the cubicle 20. In this case, the facilitating unit 33 may be attached to the outside of the door surface or side surface of the cubicle 20, and wiring may be inserted through a hole formed in the housing of the cubicle 20 and connected to the wiring structure (power line W6) inside the housing of the cubicle 20. Also, the facilitating unit 33 does not have to be attached to the outer surface of the housing of the cubicle 20, and may be connected to the wiring structure (power line W6) inside the housing of the cubicle 20.

Figure 5 is a schematic diagram showing the configuration of a cubicle according to one embodiment. As shown in Figure 5, the transformer 31 of the cubicle 20 is a single-phase three-wire type, with a power line W60A connected to the L1-phase terminal, a power line W60B connected to the L2-phase terminal, and a power line W60C connected to the N-phase terminal on the ground side. Each breaker 32 is connected to the L1-phase power line W60A and the N-phase power line W60C. Each breaker 32 is connected to each of the power lines W60A, W60B, and W60C. As a result, each breaker 32 supplies power to the distribution boards 10A, 10B, and 10C via the three power lines W60A, W60B, and W60C.

The facilitating unit 33 is provided according to the power line (phase) to which the receiving unit 4 for which the signal flow from the transmitting unit 6 is to be promoted is connected. For example, if the purpose is to promote the signal flow from the transmitting unit 6 to the receiving unit 4 provided on each power line extending from the L2 phase and the N phase, the facilitating unit 33 is provided on the power lines W60B and W60C related to the "L2 phase-N phase" combination (fourth combination) in the transformer 31, and is provided directly below the transformer 31. In this case, the transmitting unit 6 is provided, for example, on each power line W20B and W20C extending from the L2 phase and the N phase (see Figure 4). One ferrite core of the facilitating unit 33 is provided along the extension direction of the L2 phase power line W60B. The other ferrite core of the facilitating unit 33 is provided along the extension direction of the N phase power line W60C. These ferrite cores are arranged, for example, radially outside the power lines W60B, W60C, surrounding the periphery of each power line W60B, W60C.

The facilitating unit 33 facilitates the flow of signals from the transmitting unit 6 to the receiving unit 4 (see Figure 3). In other words, the facilitating unit 33 facilitates the flow of signals in the opposite direction (downstream) from the transformer 31. The facilitating unit 33 suppresses not only high-frequency noise but also signals at communication frequencies from flowing toward the transformer 31 (upstream).

To promote the above-described signal flow, the promotion unit 33 adjusts the impedance of power lines W6 and W7 so that it is greater than the impedance of power line W8. In this embodiment, the promotion unit 33 adjusts the impedance of power line W6 between the transformer 31 and the promotion unit 33 so that it is greater than the impedance of power line W8 between the transmitter 6 and the receiver 4. The difference between the impedance value of power line W6 and the impedance value of power line W8 may be, for example, 0.01 Ω, or may be 0.01 Ω or greater and 0.1 Ω or less. The difference in impedance value is not limited to the above-described value. This allows the impedance to be increased in a circuit including a power line connected to the promotion unit 33 by using at least one of the fourth, fifth, and sixth combinations of power line W6. By making the impedance of power line W6 greater than the impedance of power line W8, it is possible to prevent the signal output from transmitter 6 from flowing upstream of transmitter 6. In other words, it is possible to promote a signal that was intended to flow upstream to flow downstream of transmitter 6. Here, the upstream side refers to the power line W5 side closer to the power source 7, as viewed from the power line W8 connected to the controlled equipment 3 to which power is supplied.

Next, we will explain the operation and effects of the power line communication system 100 according to this embodiment.

In the power line communication system 100 according to this embodiment, the transformer 31 and the transmitter 6 are electrically connected, and the transmitter 6 and the receiver 4 are electrically connected. The facilitating unit 33 is provided directly below the transformer 31, and thus can facilitate signal flow on the power line W8 from the transmitter 6 to the receiver 4 in the power line W6 (an example of a first electrical path) upstream of the transmitter 6. In conventional power line communication systems, signals do not flow sufficiently downstream (toward the receiver) from the transmitter, and some or all of the signals flow upstream (toward the power source), potentially preventing the receiver from acquiring sufficient information and resulting in loss of some or all of the information that should have been acquired. In the power line communication system 100 according to this embodiment, signal flow can be facilitated between the transmitter and receiver connected to the power line to which the facilitating unit 33 is connected directly below the transformer 31. This allows the receiver 4 to properly acquire signals from the transmitter 6. Therefore, this power line communication system 100 can ensure appropriate communication quality. Furthermore, by providing the acceleration unit 33 directly below the transformer 31, there is no need to provide an acceleration unit outside each of the distribution boards 10A, 10B, and 10C, and the flow of signals can be accelerated collectively in the power lines connected to the transformer 31.

In the power line communication system 100, the receiver 4 is electrically connected to the transmitter 6 via power line W8 (an example of a second electrical path), and the promoter 33 adjusts the impedance of power line W6 so that it is greater than the impedance of power line W8. In this case, the adjustment by the promoter 33 makes the impedance of power line W6 greater than the impedance of power line W8, making it easier for signals from the transmitter 6 to flow to power line W8 than to power line W6. In other words, the flow of signals from the transmitter 6 toward the upstream power lines W6 and W7 can be suppressed. Therefore, the promoter 33 can promote the flow of signals from the transmitter 6 to the receiver 4, ensuring appropriate communication quality.

The power line communication system 100 further includes distribution boards 10A, 10B, and 10C that house a main breaker 52 installed on the power line W7 between the transformer 31 and the transmitter 6. The accelerating unit 33 is installed outside the distribution boards 10A, 10B, and 10C on the power line W6 or W7 between the transformer 31 and the distribution boards 10A, 10B, and 10C. In this case, the accelerating unit 33 is installed outside the distribution boards 10A, 10B, and 10C directly below the transformer 31. If an accelerating unit is installed in each distribution board 10A, 10B, and 10C, it would be time-consuming to determine the impedance on the transformer side and then adjust the impedance in each distribution board accordingly. For example, while installing an accelerating unit within the distribution board can prevent signals from flowing outside the distribution board, installing an accelerating unit in each distribution board requires additional work and effort. Unlike broadband power line communication (power line communication using a frequency band between 2 MHz and 30 MHz), narrowband power line communication does not require adjustments to prevent signal leakage from the transmitter outside the distribution board under Radio Law regulations. In other words, there are no restrictions on the location of the facilitating unit in narrowband power line communication. Therefore, in this power line communication system 100, there is no need to provide a facilitating unit in each of the distribution boards 10A, 10B, and 10C. By providing the facilitating unit 33 directly below the transformer 31, the signal flow can be promoted collectively. When the facilitating units 33 are provided outside the distribution boards 10A, 10B, and 10C as described above, they can be installed and adjusted collectively once the impedance of the power line W6 (or power line W7), which is part of the circuit upstream of the transmitting unit 6, is determined. Furthermore, when the impedance of power line W6 is adjusted to be greater than the impedance of power line W8, the flow of signals downstream from the transmitter 6 can be promoted, preventing signals from flowing outside the upstream of distribution boards 10A, 10B, and 10C. Therefore, this power line communication system 100 allows for easy installation and maintenance of the facilitating unit 33 depending on the type, connection status, and number of equipment downstream of transformer 31. This power line communication system 100 reduces the labor required to install and maintain a facilitating unit in each of distribution boards 10A, 10B, and 10C, and can promote signal flow collectively for each of distribution boards 10A, 10B, and 10C.

In the power line communication system 100, the signal frequency is between 10 kHz and 450 kHz.

In the power line communication system 100, the facilitating unit 33 is provided in at least one of the three-phase electrical circuits of the power line W6. In this embodiment, the facilitating unit 33 functions to facilitate signal flow in the receivers 4 and transmitters 6 connected to at least the L2 and N phases. The location of the facilitating unit 33 can be changed or expanded depending on the phase of the power line to which the receivers 4 and transmitters 6 are connected. Therefore, this power line communication system 100 can minimize the number of facilitating units 33 installed, facilitating the installation and maintenance of the facilitating units 33. Furthermore, compared to when a ferrite core is provided for one phase, when a ferrite core is provided for two phases as in this embodiment, the power line communication system 100 can more strongly facilitate signal flow in the receivers 4 and transmitters 6 connected to those two phases.

In the cubicle 20, the transformer 31 and the power line communication system 100 having the receiving unit 4 and transmitting unit 6 are electrically connected by power lines W6 and W7. The accelerating unit 33 is provided directly below the transformer 31, and therefore can accelerate the flow of signals from the transmitting unit 6 to the receiving unit 4 in the cubicle 20 upstream of the transmitting unit 6. This allows the receiving unit 4 to properly acquire signals from the transmitting unit 6. This allows the cubicle 20 to ensure appropriate communication quality. Furthermore, there is no need to provide an accelerating unit in each of the distribution boards 10A, 10B, and 10C connected to the cubicle 20. The accelerating unit 33 provided in the cubicle 20 can collectively accelerate the flow of signals in the electrical circuit (power line W8) downstream of the cubicle 20.

The cubicle 20 is electrically connected to the transformer 31 by a power line W6 and has multiple breakers 32 installed between the transformer 31 and the transmitting unit 6, and the accelerating unit 33 is installed between the transformer 31 and the breakers 32. In this case, if the accelerating unit is installed and maintained downstream of each breaker, the labor required to install and maintain the accelerating unit increases or decreases depending on the number of breakers. On the other hand, in this embodiment, the accelerating unit 33 is installed between the transformer 31 and the multiple breakers 32, upstream before branching into the multiple breakers 32, so the labor required to install and maintain the accelerating unit 33 can be reduced compared to installing it downstream of each breaker.

The present invention is not limited to the above-described embodiments.

For example, the arrangement, positions, and number of the controlled equipment 3, receiving unit 4, transmitting unit 6, facilitating unit 33, and load equipment on each floor shown in Figure 3 are not particularly limited and may be changed as appropriate.

For example, the combination of power lines to which the transmitter 6 is connected is not limited. The transmitter 6 may be provided in the main breaker 52 by being connected to the power lines W20A and W20C associated with the "L1 phase-N phase" combination (second combination) in the main breaker 52. This allows the signal from the transmitter 6 to pass through the power lines W20A and W20C associated with the "L1 phase-N phase" combination. The transmitter 6 may be provided in the main breaker 52 by being connected to the power lines W20A and W20B associated with the "L1 phase-L2 phase" combination (third combination) in the main breaker 52. This allows the signal from the transmitter 6 to pass through the power lines W20A and W20B associated with the "L1 phase-L2 phase" combination.

Furthermore, the number of transmitter units 25 of the transmitter unit 6 is not limited. Multiple transmitter units 25 may be provided within the distribution board 10A, and each may be connected to the power lines associated with multiple combinations of the first, second, and third combinations described above. This allows the signal output from the transmitter unit 6 to be transmitted to the receiver unit 4 connected to each power line.

Furthermore, the combination of power lines to which the facilitating unit 33 is connected is not limited. For example, if the purpose is to promote the flow of signals from the transmitting unit 6 to the receiving units 4 provided on each power line extending from the L1 phase and the N phase, the facilitating unit 33 may be provided on the power lines W60A, W60C related to the "L1 phase-N phase" combination (fifth combination) in the transformer 31, and may be provided directly below the transformer 31. In this case, the transmitting unit 6 is provided on each power line extending from the L1 phase and the N phase, for example. One ferrite core of the facilitating unit 33 is provided along the extension direction of the L1 phase power line W60A. The other ferrite core of the facilitating unit 33 is provided along the extension direction of the N phase power line W60C.

For example, if the purpose is to promote the flow of signals from the transmitter 6 to the receivers 4 provided on each power line extending from the L1 and L2 phases, the promoter 33 may be provided on the power lines W60A and W60B associated with the "L1-L2 phase" combination (sixth combination) in the transformer 31, and may be provided directly below the transformer 31. In this case, the transmitter 6 is provided on each power line extending from the L1 and L2 phases, for example. One ferrite core of the promoter 33 is provided along the extension direction of the L1-phase power line W60A. The other ferrite core of the promoter 33 is provided along the extension direction of the L2-phase power line W60B.

Furthermore, the number of ferrite cores in the accelerating unit 33 is not limited. The number of ferrite cores in the accelerating unit 33 may be set according to the number of power lines extending from each phase of the transformer 31. For example, one ferrite core may be provided in the cubicle 20 for each of the three phases, L1, L2, and N (a total of three). This makes it possible to accommodate the fourth, fifth, and sixth combinations described above. That is, the accelerating unit 33 may include a ferrite core provided along the extension direction of the L1-phase power line W60A, a ferrite core provided along the extension direction of the L2-phase power line W60B, and a ferrite core provided along the extension direction of the N-phase power line W60C. In this case, the flow of signals can be collectively promoted to the receiving unit 4 and the transmitting unit 6 connected to any of the L1, L2, and N phases.

For example, one ferrite core may be provided within the cubicle 20 for three phases: L1, L2, and N. In this case, the ferrite core of the facilitating unit 33 is provided for one of the two power lines (two phases) connected to the receiving unit 4 for which the signal flow from the transmitting unit 6 is to be promoted. This configuration is applied, for example, when the phases to which the receiving unit 4 and transmitting unit 6 are connected have already been determined. In this case, the facilitating unit 33 can be provided more easily than when ferrite cores are provided for multiple phases, making it easier to promote signal flow.

Figure 6 is a schematic diagram showing the configuration of a cubicle related to a modified example. As shown in Figure 6, the cubicle 20 may be provided with a terminal block 34. The L1-phase power line W60A of the transformer 31 is connected to terminal 35A of the terminal block 34, the L2-phase power line W60B is connected to terminal 35B of the terminal block 34, and the grounded N-phase power line W60C is connected to terminal 35C of the terminal block 34. The breakers 32 for each of the levels F1, F2, and F3 are connected to the L1-phase terminal 35A, the L2-phase terminal 35B, and the N-phase terminal 35C, respectively. As a result, the transformer 31 supplies power to the controlled equipment 3 and the receiving unit 4 on each of the levels F1, F2, and F3 via the three power lines W60A, W60B, and W60C. The connection targets of the facilitating unit 33A for each of the power lines W60A, W60B, and W60C are the same as those shown in FIG. 5. The facilitating unit 33A is provided, for example, between the transformer 31 and the terminal block 34. In this case, the number of power lines on which the facilitating unit 33A can be installed can be reduced compared to when the facilitating unit is provided downstream of the terminal block or downstream of multiple breakers, thereby reducing the installation and maintenance man-hours. Note that the facilitating unit 33A may also be provided, for example, between the terminal block 34 and multiple breakers 32. In this case, the number of power lines on which the facilitating unit 33A can be installed can be reduced compared to when the facilitating unit is provided downstream of multiple breakers, thereby reducing the installation and maintenance man-hours.

The transmitting unit 6 may be provided in the cubicle 20. In this case, the facilitating unit 33 is provided between the transformer 31 and the transmitting unit 6.

Figure 7 is a schematic diagram showing a power line communication system according to a modified example. As shown in Figure 7, the power line communication system 100A does not need to include a cubicle. The power line communication system 100A includes a transmitter 6A electrically connected to a voltage-changing transformer 31A via power lines W6 and W7 and transmitting signals for narrowband power line communication; a receiver 4A electrically connected to the transmitter 6A via power line W8 and receiving the signals; and a promotion unit 33A located directly below the transformer 31A on the power line W6 and promoting the flow of signals from the transmitter 6A to the receiver 4A. The receiver 4A is a slave unit provided for the controlled equipment 3A (lighting in Figure 7). The transformer 31A is electrically connected to the power source 7 via power line W5. The transmitter 6A is provided in a distribution board 10D electrically connected to the transformer 31A. The promotion unit 33A is provided between the transformer 31A and the distribution board 10D. That is, the acceleration unit 33A is provided immediately below the transformer 31A and upstream of the distribution board 10D. In this modified example, devices and configurations with the same names as those in the above-described embodiment, but with different reference numerals, exhibit the same functions and effects.

The building BD2 to which the power line communication system 100A shown in FIG. 7 is applied may be, for example, a facility such as a detached house. If the building BD2 in which the receiving unit 4 and transmitting unit 6 are installed is a detached house, for example, the transformer 31A is not installed in a cubicle. The transformer 31A is installed, for example, on a utility pole outside the building BD2. The transformer 31A is electrically connected to the distribution board 10D in the building BD1 via the power line W7. A power line communication system 100A having such a configuration can still achieve the same functions and effects as the power line communication system 100.

The signal strength of the receiving unit was measured by installing the booster directly below the transformer, and the function and effectiveness of the booster were verified.

[Comparative Example 1]
FIG. 8A is a circuit diagram of a power line communication system according to a comparative example before the installation of a transformer and a promotion unit. As shown in FIG. 8A, a power line communication system 100P according to comparative example 1 includes a controlled facility 3P, a receiving unit 4P, and a transmitting unit 6P. The controlled facility 3P, the receiving unit 4P, and the transmitting unit 6P are electrically connected in parallel. Each component is operated by a power source (not shown). The transmitting unit 6P continuously outputs a power line communication signal (PLC signal) of 100 kHz to 400 kHz to the controlled facility 3P and the receiving unit 4P. The controlled facility 3P is an example of a load. The receiving unit 4P is, for example, a spectrum analyzer. The receiving unit 4P has a resistance value of 50 Ω and is connected to the end of the circuit. The receiving unit 4P detects a signal from the transmitting unit 6P.

Figure 8(b) is a graph of experimental results showing the signal spectrum at the receiving unit before the installation of the transformer and acceleration unit. As shown in Figure 8(b), the receiving unit 4P detected signals of approximately -20 dBm in the frequency range of 100 kHz to 400 kHz. It was also shown that the receiving unit 4P detected signals with approximately constant strength in the frequency range of 100 kHz to 400 kHz, which is the frequency band of the signal output from the transmitting unit 6P. Furthermore, signals of approximately -70 dBm were detected in other frequency bands not output from the transmitting unit 6P, such as 50 kHz to less than 100 kHz and greater than 400 kHz to less than 1000 kHz.

[Comparative Example 2]
9A is a circuit diagram of a power line communication system according to a comparative example after a transformer is installed but before a promotion unit is installed. As shown in FIG. 9A, a power line communication system 100Q according to comparative example 2 includes a controlled facility 3Q, a receiving unit 4Q, and a transmitting unit 6Q. The power line communication system 100Q further includes a transformer 31Q. The controlled facility 3Q, the receiving unit 4Q, the transmitting unit 6Q, and the transformer 31Q are electrically connected in parallel. The transmitting unit 6Q is provided between the transformer 31Q and the controlled facility 3Q and the receiving unit 4Q. The controlled facility 3Q, the receiving unit 4Q, and the transmitting unit 6Q operate using power supplied via the transformer 31Q. The transformer 31Q receives power from a power source (not shown). The transmitting unit 6Q continuously outputs a power line communication signal of 100 kHz or more and 400 kHz or less to the controlled facility 3Q and the receiving unit 4Q. The controlled facility 3Q is an example of a load. The receiver 4Q is, for example, a spectrum analyzer. The receiver 4Q has a resistance value of 50 Ω and is connected to the end of the circuit. The receiver 4Q detects a signal from the transmitter 6Q. The transformer 31Q has the same function as the transformer 31 in the above embodiment.

Figure 9(b) is a graph of experimental results showing the signal spectrum at the receiving unit after the transformer was installed but before the promotion unit was installed. As shown in Figure 9(b), receiving unit 4Q detected signals in the range of -80 dBm to -55 dBm in the frequency range of 100 kHz to 400 kHz. It was also confirmed that the higher the frequency in the frequency range of 100 kHz to 400 kHz, the higher the detected strength. Furthermore, in other frequency bands not output from transmitting unit 6Q, such as 50 kHz to less than 100 kHz and greater than 400 kHz to less than 1000 kHz, signals of approximately -90 dBm were detected.

[Example]
FIG. 10A is a circuit diagram of a power line communication system according to an embodiment after a transformer and a promotion unit are installed. As shown in FIG. 10A, a power line communication system 100R according to the embodiment includes a controlled facility 3R, a receiving unit 4R, a transmitting unit 6R, and a promotion unit 33R. The power line communication system 100R further includes a transformer 31R. The controlled facility 3R, the receiving unit 4R, the transmitting unit 6R, and the transformer 31R are electrically connected in parallel. The transmitting unit 6R is provided between the transformer 31R and the controlled facility 3R and the receiving unit 4R. The controlled facility 3R, the receiving unit 4R, and the transmitting unit 6R operate using power supplied via the transformer 31R. The transformer 31R receives power from a power source (not shown). The transmitting unit 6R continuously outputs a power line communication signal of 100 kHz or more and 400 kHz or less to the controlled facility 3R and the receiving unit 4R. The controlled equipment 3R is an example of a load. The receiver 4R is, for example, a spectrum analyzer. The receiver 4R has a resistance value of 50 Ω and is connected to the end of the circuit. The receiver 4R detects a signal from the transmitter 6R. The transformer 31R has the same function as the transformer 31 in the above-mentioned embodiment. The accelerator 33R is provided on each of the two power lines connected to the transmitter 6R. The accelerator 33R is, for example, a ferrite core.

Figure 10(b) is a graph of experimental results showing the signal spectrum at the receiving unit after the transformer and acceleration unit were installed. As shown in Figure 10(b), the receiving unit 4R detected signals in the range of approximately -20 dBm in the frequency range of 100 kHz to 400 kHz. It was also shown that the receiving unit 4P detected signals with approximately constant strength in the range of 100 kHz to 400 kHz, which is the frequency band of the signal output from the transmitting unit 6P. Furthermore, signals of approximately -70 dBm were detected in other frequency bands not output from the transmitting unit 6R, for example, from 50 kHz to less than 100 kHz and from more than 400 kHz to less than 1000 kHz.

Comparing the results of Comparative Example 1 with those of the Example revealed that even when transformer 31R is connected to power line communication system 100P, the signal strength detected by receivers 4P and 4R is substantially the same regardless of the frequency band. Comparing the results of Comparative Example 1 and Comparative Example 2, on the other hand, revealed that when transformer 31Q is connected to power line communication system 100P, the signal strength detected by receivers 4P and 4Q decreases in each frequency band. Furthermore, in Comparative Example 1 and the Example, within the frequency range of 100 kHz to 400 kHz, which is the frequency band of the signals output from transmitters 6P, 6Q, and 6R, the signal strength detected by receivers 4P and 4R is constant regardless of frequency. However, within this frequency band, in Comparative Example 2, the signal strength detected by receiver 4Q varies by frequency. These results demonstrate that, even when a transformer is connected to the circuits of the controlled equipment, receiver, and transmitter, providing a promotion unit enables the receiver to properly detect signals from the transmitter.

When the transformer 31Q is connected directly to the transmitter 6Q as shown in (a) of FIG. 9, the signal output from the transmitter 6Q flows not only to the receiver 4Q (downstream) but also to the transformer 31Q (upstream), which is presumably why the signal strength detected by the receiver 4Q in Comparative Example 2 is reduced. On the other hand, when the transformer 31R is connected to the transmitter 6R via the accelerator 33R as shown in (a) of FIG. 10, the signal output from the transmitter 6R is prevented from flowing to the transformer 31R (upstream) and is accelerated to flow to the receiver 4Q (downstream). Therefore, it is presumed that the signal strength detected by the receiver 4R is similar to the signal strength detected by the receiver 4P in the embodiment. Therefore, by providing an accelerator between the transformer and the transmitter, the power line communication system can ensure appropriate communication quality between the transmitter and receiver.

3, 3P, 3Q, 3R...controlled equipment, 4, 4A, 4P, 4Q, 4R...receiving unit, 6, 6A, 6P, 6Q, 6R...transmitting unit, 7...power supply, 10A, 10B, 10C, 10D...distribution board (power distribution equipment), 20...cubicle (power distribution equipment), 31, 31A, 31Q, 31R...transformer (power supply unit), 32...breaker, 33...promotion unit, 50...power distribution equipment, 51...power supply unit, 52...main breaker, 100...power line communication system.

Claims (6)

a transmitter electrically connected to the transformer that converts a voltage from high to low by a first electric path , the transmitter transmitting a signal in a frequency band of 10 kHz to 450 kHz in power line communication;
a receiving unit electrically connected to the transmitting unit and receiving the signal;
a distribution board accommodating a main breaker provided on the first electric circuit between the transformer and the transmitting unit;
a promotion unit that is provided directly below the transformer on the first electric path, outside the distribution board, on the first electric path between the transformer and the distribution board, and that promotes the flow of the signal from the transmitting unit to the receiving unit and suppresses the flow of the signal from the transmitting unit to the transformer side ;
A power line communication system comprising: the receiving unit is electrically connected to the transmitting unit by a second electrical path,
The power line communication system according to claim 1 , wherein the promoting unit adjusts the impedance of the first electrical path so that it is greater than the impedance of the second electrical path. 3. The power line communication system according to claim 1, wherein the power line communication is performed in a DCSK system. The power line communication system according to claim 1 , wherein the facilitating unit is provided in at least one of the first electric circuits, which are divided into three phases. A cubicle connected to a power line communication system including a distribution board that houses a main breaker, and a transmitter that transmits a signal in a frequency band of 10 kHz to 450 kHz in power line communication and a receiver that receives the signal,
a transformer electrically connected to the power line communication system by a first electric path, the transformer changing a voltage from a high voltage to a low voltage ;
a promotion unit provided in the first electric path between the distribution board and the transformer immediately below the transformer, the promotion unit promoting the flow of the signal toward the downstream side, which is the direction in which power is supplied , and suppressing the flow of the signal toward the upstream side, which is opposite to the downstream side ;
Equipped with a cubicle. the cubicle has a plurality of breakers electrically connected to the transformer by the first electric path and provided between the transformer and the transmitting unit,
The cubicle according to claim 5 , wherein the facilitating section is provided between the transformer and the breaker.