TW201817178A - Communication system, terminating device and communication subsystem - Google Patents

Abstract

In order to improve the reliability of power-line communication, a communication system (1) includes power-line communication devices (3) and two terminating devices (2). The power-line communication devices (3) superpose a communication signal (S1) on AC power supplied to two power conductors (9). The two terminating devices (2) terminate a transmission line of the communication signal (S1). The two terminating devices (2) cause impedance between the two power conductors (9) in a frequency band of the communication signal (S1) to be smaller than impedance between the two power conductors (9) at a frequency of AC voltage (V1) applied across the two power conductors (9).

Description

Communication system, termination device and communication subsystem

The present invention relates to communication systems, termination devices, and communication subsystems, and more particularly to a communication system configured to perform power line communication, a configuration configured to attach to a power conductor for the power line communication Termination device and a communication subsystem configured in the communication system to perform power line communication.

In the configuration of an associated power line carrier communication system, it is known to realize mutual communication between power line carrier devices via a power line as one communication channel (for example, JP 2009-194782 A (hereinafter referred to as "File 1")). The power line carrier communication system described in Document 1 comprises: a communication signal conductor; an electromagnetic coupler attached by inserting the communication signal conductor and the power line into the device; and two metal parts, And the like are connected to each other, wherein the two metal parts individually cover the incoming and outgoing channels of the power line outside the power line carrier device on both ends. The metal component is attached to the power line, wherein the metal component partially covers the entire circumference of the respective wires of the power line. The attached metal component increases the capacitance between each metal component and a conductor corresponding to one of the power lines, thereby increasing the capacitance between the incoming and outgoing channels of the power line. The metal component increases the capacitance between the incoming and outgoing channels of the power line covered by the metal component, thereby reducing the power line relative to one of the communication signals on the communication signal conductor transmitted from the power line carrier communication system. The impedance between the incoming and outgoing channels. By means of the power line carrier communication system described in the document 1, for example, a space between the respective metal parts and the conductor corresponding to one of the power lines, a dielectric constant of the conductor covering the conductor, and an area of the metal part covering the conductor Determine the capacitance between the incoming and outgoing channels of the power line. For example, there is a possibility that the thickness of the respective wire insulation of the power line varies between the regions of the power line and the respective dielectric constants of the power lines vary between the regions of the power line. In this case, even if the metal parts are attached to the respective wire insulation of the power line, the capacitance between the metal parts and the corresponding conductor of one of the power lines may deviate from a prescribed value, and the power line of the high frequency signal with respect to the communication signal The impedance between the two conductors can also deviate from a specified value. With power line communication, it is difficult to superimpose a communication signal on the AC power supplied through the power line with a large impedance between the conductors of the power line with respect to the high frequency signal of the communication signal. Therefore, the reliability of power line communication is apt to reduce.

The present invention has been achieved in view of the above circumstances, and an object of the present invention is to provide a communication system, a termination device, and a communication subsystem capable of improving the reliability of power line communication. A communication system in accordance with an aspect of the present invention includes a power line communication device and two termination devices. The power line communication devices are configured to superimpose a communication signal on AC power supplied to the two power conductors. The two termination devices are configured to terminate one of the communication signal transmission lines on the two power conductors. Each of the power line communication devices has two cores corresponding to the two power conductors and one of the respective through holes inserted in the two cores. Each of the power line communication devices has a first function for transmitting the communication signal through the signal wire and a communication signal for transmitting a communication signal from another power line communication device of the power line communication device through the signal wire. A second function. The respective cores of the power line communication devices are disposed between the two termination devices along the two power conductors. The two termination devices are configured such that an impedance between the two power conductors in a frequency band of the communication signal is less than the two power conductors at a frequency of one of the AC voltages applied across the two power conductors Impedance between. A termination device in accordance with one aspect of the present invention is employed as a termination device in the communication system. A communication subsystem in accordance with an aspect of the present invention includes at least one power line communication device of the power line communication devices and the termination device.

A communication system, a termination device, and a communication subsystem according to an embodiment of the present invention will be explained below. Note that each of Embodiments 1 and 2 (including modified examples) explained below is only one of various embodiments of the present invention. The following embodiments may be modified according to design requirements as long as the object of the present invention can be attained. (Embodiment 1) Overview of Communication System A communication system 1 according to the present embodiment will be explained with reference to a specific example of the present embodiment described later. The communication system 1 comprises a power line communication device 3 (two power line communication devices 3 in the example of Fig. 1) and two termination devices 2. Each of the power line communication devices 3 has two cores 4 having respective through holes 41 allowing the two power conductors 9 to be individually inserted, and a signal wire 6 inserted into the respective through holes 41 of the two cores 4. And a communication circuit 30. In the example of FIG. 1, each of the two cores 4 is a ring core, and the signal conductors 6 are electrically coupled to the communication circuit 30 to form a loop. The communication circuit 30 is configured to: superimpose one communication signal to be transmitted on the AC power passing through the two power conductors 9 via the signal conductor 6 and the two cores 4; and receive the superposition on the AC via the signal conductor 6 and the two cores 4 One of the power is transmitted to the communication signal. Each of the two termination devices (terminating device 2 in the example of Figure 1) is electrically connected to two power conductors 9 such that the respective cores 4 of the power line communication device 3 are disposed between the terminating devices. Each of the two termination devices is, for example, a data machine for performing power line communication. The communication system 1 thus enables the power line communication device 3 to perform power line communication with each other via the two power conductors 9. Each of the two termination devices 2 is configured such that the impedance between the two power conductors 9 in one of the frequency bands of the communication signal S1 superimposed on the AC power is less than the AC voltage applied across the two power conductors 9. The impedance between two power conductors 9 at one of the frequencies of V1. Here, "[the frequency band of the communication signal S1" means a frequency band of the carrier of the communication signal S1. The two termination devices 2 terminate the transmission line of one of the communication signals S1 on the two power conductors 9, thereby forming a closed loop transmission line. The two termination devices 2 make the impedance of the transmission line less than the impedance between the two power conductors 9 at the frequency of the AC voltage V1 applied across the two power conductors 9. A specific example of this embodiment will be explained hereinafter with reference to FIG. 1. A communication system 1 is installed in a consumer facility including a power supply 100, a first distribution board 101, and a second distribution board 102 (distribution board). An example of a consumer facility is an office building, but examples thereof may further include buildings such as commercial facilities, factories, and hospitals. In one example, power supply 100 is a power receiving facility (such as a small compartment (stand-alone terminal service desk) facility that includes a transformer (distribution transformer) and the like). In one example in Japan, the power supply 100 is mounted on the roof of one of the consumer facilities, in one of the electrical rooms or the like. The transformer of the power supply 100 is configured to convert an AC voltage of 6600 [V] supplied from a power station via a [一] substation to an AC voltage of 200 [V] (or 100 [V]). The AC voltage distribution system is, for example, a single phase three-wire system. The two power conductors 9 are electrically connected to the first switchboard 101 and the second switchboard 102. An AC voltage of L1 phase is applied across one of the first power conductor 9 and one N phase conductor (neutral conductor) of the two power conductors 9. An AC voltage of L2 phase is applied across one of the two power conductors 9 and the N-phase conductor. The AC voltage V1 applied across the two power conductors 9 has an amplitude that is twice as large as the amplitude of the AC voltage of, for example, the L1 phase. The frequency of the AC voltage V1 is equal to the mains frequency and is, for example, 50 [Hz] or 60 [Hz]. In the following explanation, the N-phase conductor is omitted therefrom and the electrical connection relationship with the N-phase conductor is also omitted therefrom. The first switchboard 101 includes a main breaker and a branch breaker. The first distribution board 101 has three input terminals on one of its primary sides, which allow electrical connection to the power supply 100. One of the branch circuit breakers of the first switchboard 101 has three output terminals on one of its secondary sides, and the two output terminals of the three output terminals allow electrical connection to the two power conductors 9. The second switchboard 102 includes a cabinet 103 and a switchboard internal device. The cabinet 103 has a body that is configured to attach to a building structural component (such as, for example, a wall), and a cover that is configured to cover the body at a side of the body opposite the wall. The cabinet 103 is made of a non-conductive material. The switchboard internals are disposed in the interior of one of the cabinets 130 (between the body and the cover). An example of a switchboard internal device includes a main breaker 110 (circuit breaker) and a branch breaker 120 (only one branch breaker 120 is shown in Figure 1). That is, the second switchboard 102 includes the main breaker 110 and the branch breaker 120. The main breaker 110 has three primary terminals and three secondary terminals. Hereinafter, the two primary terminals of the three primary terminals electrically connected to the two power conductors 9 are referred to as "two primary terminals 111". The two secondary terminals of the three secondary terminals corresponding to the two primary terminals 111 are referred to as "two secondary terminals 112". The two secondary terminals 112 will be electrically connected to the two power conductors 9. The main breaker 110 includes two primary terminals 111 that are electrically connected to the first ends of the two power conductors 9. The branch circuit breaker in the first switchboard 101 has two output terminals on the secondary side that are electrically connected to the second ends of the two power conductors 9. Main breaker 110 includes two secondary terminals 112 that are each electrically coupled to load 300 via branch circuit breaker 120 (only one load 300 is shown in FIG. 1). The main breaker 110 is, for example, a residual current circuit breaker (residual current operated circuit breaker) and is configured to electrically connect two secondary terminals 112 to two primary terminals 111 and to have two secondary The terminal 112 is disconnected from the two primary terminals 111. That is, main breaker 110 is configured to make and disconnect electrical connections for supplying AC power to branch circuit breaker 120. Each of the branch circuit breakers 120 is, for example, an overcurrent circuit breaker (overcurrent protection circuit breaker). Each of the branch circuit breakers 120 is configured to make and break an electrical connection for supplying AC power to a load 300 that is electrically connected to one of the two output terminals. The power supply 100 is configured to supply the AC voltage V1 and the AC current I1 to the two power conductors 9 via the first distribution board 101. One of the L1 phase output terminals of the branch circuit breaker in the first switchboard 101 is electrically connected to the first power conductor 9 of the two power conductors 9. One of the L2 phase output terminals of the branch circuit breaker in the first switchboard 101 is electrically connected to the second power conductors 9 of the two power conductors 9. (2) Details (2. 1) Power Line Communication Apparatus Each of the power line communication apparatuses 3 has two cores individually corresponding to two power conductors 9, a signal conductor 6 and a communication circuit 30. Each of the two cores 4 is provided with a circular through hole 41 in one of its centers to allow the signal wire 6 to be inserted. The two cores 4 and the signal conductors 6 form a coupler 5. The signal conductor 6 is electrically connected to a communication circuit 30 of a corresponding power line communication device 3. Each of the two cores 4 of the coupler 5 has a ring shape and is made of a magnetic material such as, for example, ferrite. The first power conductor 9 (L1 phase) of the two power conductors 9 is inserted into the through holes 41 of the first core 4 of one of the two cores 4. The second power conductor 9 (L2 phase) of the two power conductors 9 is inserted into the through holes 41 of the second core 4 of one of the two cores 4. The signal wires 6 are inserted into the through holes 41 of both the cores 4. The coupler 5 is configured to superimpose respective communication signals S1 (which are transmitted from the power line communication device 3 via the signal wires 6) on the AC power supplied from the power supply 100 through the two power conductors 9. Each of the couplers 5 has an inductive coupling device of two cores 4. Each of the power line communication devices 3 has a first function for transmitting a communication signal S1 via the signal conductor 6. When the communication circuit 30 of each power line communication device 3 transmits the communication signal S1 through the signal conductor 6, the magnetic flux appears in the core 4 when the communication signal S1 passes through the core 4 of the coupler 5. The communication signal S1 is superimposed on the AC current I1 flowing through the power conductor 9 by the magnetic flux appearing in the core 4. Therefore, the communication signal S1 is superimposed on the AC power supplied through the two power conductors 9. In short, the first function of each power line communication device 3 is for superimposing the communication signal S1 on one of the AC powers supplied through the power conductor 9. Each power line communication device 3 has a second function for receiving one of the communication signals S1 transmitted from another power line communication device 3 of the power line communication device 3 via the signal line 6. When the communication signal S1 superimposed on the AC current I1 passes through the core 4 of the coupler 5, a magnetic flux appears in the core 4. The communication signal S1 is transmitted to the signal conductor 6 by the magnetic flux appearing in the core 4. The communication circuit 30 of the power line communication device 3 can receive the communication signal S1 via the signal line 6. In short, the second function of the power line communication device 3 is for receiving a function of the communication signal S1 superimposed on the AC power supplied through the power conductor 9. The two power line communication devices 3 are referred to as power line communication devices 31 and 32 to distinguish between them. In addition, the communication circuit 30 of the power line communication device 31 is referred to as a communication circuit 301, and the communication circuit 30 of the power line communication device 32 is referred to as a communication circuit 302. The two couplers 5 (when distinguishing them etc.) are referred to as couplers 51 and 52. In addition, the signal conductor 6 in the coupler 51 is referred to as a signal conductor 61, and the signal conductor 6 in the coupler 52 is referred to as a signal conductor 62. The power line communication devices 31 and 32 can perform power line communication with each other through the two power conductors 9 by the first and second functions. The communication circuit 301 of the power line communication device 31 is electrically connected to the signal wire 61. The communication circuit 301 is configured to vary the intensity of the current supplied to the signal conductor 61, thereby providing a communication signal S1 to the signal conductor 61. The communication circuit 301 provides, for example, a communication signal S1 to the signal conductor 61 having an amplitude modulated carrier having a frequency of about 2 [MHz] to 30 [MHz]. One of the frequency bands of the communication signal S1 is, for example, one of the frequencies including one of 2 [MHz] to 30 [MHz]. One of the frequency bands of the communication signal S1 is higher than the frequency of the AC voltage V1. Note that the aforementioned frequency band of the communication signal S1 is only an example, and it is desirable that the frequency band of the communication signal S1 is limited to the aforementioned frequency band. When the communication circuit 301 supplies the communication signal S1 to the signal conductor 61, the magnetic flux appears in each of the cores 4 in accordance with the communication signal S1. The communication circuit 301 supplies the signal line 61 with a communication signal S1 to change the magnetic flux in each of the cores 4 in the coupler 51, thereby superimposing the communication signal S1 on the AC power supplied through the two power conductors 9. The communication circuit 302 of the power line communication device 32 is electrically connected to the signal conductor 62. When the communication signal S1 superimposed on the AC current I1 passes through each of the cores 4 in the coupler 52 of the power line communication device 32, a magnetic flux occurs in each of the cores 4, and a communication signal S1 is supplied to the signal wires 62 in accordance with the magnetic flux. . Communication circuit 302 receives communication signal S1 that is provided to signal conductor 62. In this context, the frequency of the AC current I1 is the mains frequency and is, for example, 50 [Hz] or 60 [Hz]. Each of the AC current I1 and the communication signal S1 is an AC signal, and thus the direction of the AC current I1 and the communication signal S1 shown in FIG. 1 is an example. Although an example in which the power line communication device 31 transmits the communication signal S1 to the power line communication device 32 is explained, the power line communication device 32 can also transmit a communication signal S1 to the power line communication device 31. In this case, the power line communication device 32, the communication circuit 302, the signal wire 62, and the coupler 52 must be used instead of the power line communication device 31, the communication circuit 301, the signal wire 61, and the coupler 51, respectively. (2. 2) Termination device Each of the two termination devices 2 has two connection terminals 200 and a capacitor 7. The capacitor 7 is electrically connected between the two connection terminals 200. Each of the two termination devices 2 is attached to two power conductors 9 such that their respective two connection terminals 200 are electrically connected to the two power conductors 9. The capacitor 7 has a frequency characteristic such that the impedance between the two power conductors 9 in the frequency band of the communication signal S1 is relatively smaller than the impedance between the two power conductors 9 at the frequency of the AC voltage V1. Therefore, the terminating means 2 causes the impedance between the two power conductors 9 in the frequency band of the communication signal S1 to be smaller than the impedance between the two power conductors 9 at the frequency of the AC voltage V1. In other words, the two termination devices 2 terminate the transmission line of one of the communication signals S1 on the two power conductors 9. Therefore, the transmission line of the communication signal S1 is a closed loop transmission line composed of two termination devices 2 and two power conductors 9. Since the impedance between the two power conductors 9 in the frequency band of the communication signal S1 becomes smaller than the impedance between the two power conductors 9 at the frequency of the AC voltage V1, the transmission line facilitates superimposing the communication signal S1 thereon. Each of the two termination devices 2 further includes a pressure limiting device 71. The two ends of the voltage limiting device 71 are electrically connected to the two connection terminals 200, respectively. An example of the pressure limiting device 71 includes a varistor and the like. When receiving a surge voltage exceeding a prescribed voltage between the two power conductors 9 due to, for example, a lightning strike, the voltage limiting device 71 conducts and then allows the surge voltage to flow therethrough, thereby preventing the application across the capacitor 7 from exceeding the regulation. The voltage of the voltage. In other words, if a surge voltage exceeding a predetermined voltage is applied across the two power conductors 9, the voltage limiting device 71 limits the voltage across the two power conductors 9 to a predetermined voltage or less. One of the two termination devices 2 is electrically connected to the two power conductors 9 between the first distribution board 101 and the coupler 51 of the power line communication device 31. The other of the two termination devices 2 is electrically connected to the two power conductors 9 between the second distribution board 102 and the coupler 52 of the power line communication unit 32. Therefore, the power line communication device 3 is disposed between the two termination devices 2 along the two power conductors 9. The two termination devices 2 and the two power conductors 9 form a closed loop transmission line that allows AC current, which is the carrier of the communication signal S1, to flow through the core 4 of the power line communication device 3. (2. 3) Communication Subsystem According to one embodiment, the communication subsystem 10 includes a power line communication device 3 and a termination device 2. The communication system 1 according to the present embodiment includes two communication subsystems 10. In the communication system 1 according to the present embodiment, the first communication subsystem 10 of one of the two communication subsystems 10 includes the power line communication device 31 and the termination device 2 of the two termination devices 2 closer to the first distribution board 101. The second communication subsystem 10 of one of the two communication subsystems 10 comprises a power line communication device 32 and a termination device 2 of the two termination devices 2 closer to the second distribution board 102. (3) Advantages of Termination Device The two termination devices 2 make the impedance between the two power conductors 9 in the frequency band of the communication signal S1 smaller than the impedance between the two power conductors 9 at the frequency of the AC voltage V1. Therefore, the AC current as the carrier of the communication signal S1 superimposed on the AC current I1 will easily flow between the two power conductors 9 via the two termination devices 2. In other words, the two termination devices 2 transmit a communication signal S1 superimposed on the AC power between the two power conductors 9. Since the AC current as the carrier of the communication signal S1 flows relatively easily through the closed loop transmission line composed of the two termination means 2 and the two power conductors 9, the attenuation of the communication signal S1 is suppressed. In other words, the two termination devices 2 are electrically connected to the two power conductors 9, and the closed loop transmission line has a smaller impedance in the frequency band of the communication signal S1 and thus suppresses the attenuation of the communication signal S1. Therefore, the loss of the communication signal S1 is reduced. Therefore, the reliability of the power line communication can be improved when the power line communication device 3 transmits and receives the communication signal S1 by power line communication. Note that each of the two termination devices 2 includes a capacitor 7, but is not limited thereto. Each of the two termination devices 2 may comprise a suitable electronic circuit that causes the impedance between the two power conductors 9 in the frequency band of the communication signal S1 to be less than the impedance between the two power conductors 9 at the frequency of the AC voltage V1. . Each of the two termination devices 2 may comprise an electronic circuit electrically coupled in series with the capacitor 7, and may comprise an electronic circuit in place of the capacitor 7. The communication system 1 can include three or more power line communication devices 3. For example, the communication system 1 can include an additional power line communication device 3 between two communication subsystems 10 disposed along two power conductors 9. The communication system 1 performs power line communication by electrically connecting the two power conductors 9 of the first switchboard 101 and the second switchboard 102, but is not limited thereto. Two power conductors 9 can be electrically connected to two suitable devices. In this case, the power line communication device 3 needs to be electrically connected to the two power conductors 9 so as to be disposed between the two termination devices 2 along the two power conductors 9. The communication system 1 can be used in a power distribution system in which AC power is supplied by a single-phase two-wire system. (Modified Example 1 in Embodiment 1) A communication system 1a which is a modified example 1 of Embodiment 1 will be explained with reference to FIG. In the communication system 1a shown as modified example 1 in FIG. 2, a first switchboard 101 (see FIG. 1) and one of the two communication subsystems 10 closer to the first switchboard 101 are not shown. (see picture 1). The communication system 1a as the modified example 1 of the embodiment 1 is different from the communication system 1 of the embodiment 1 in that one termination device 2 of two termination devices 2 is provided in a second distribution board 102 (distribution board). The other configuration of the communication system 1a is the same as that of the communication system 1 of the first embodiment. The same elements are assigned the same as the element symbols depicted in Embodiment 1, and the description thereof is omitted as appropriate. In the communication system 1a as a modification example 1, the distribution board 102 (distribution board) is connected to the first end of the power conductor 9. One of the two termination devices 2 is provided in a main breaker 110 (distributor internal device), and the main breaker 110 is disposed inside the cabinet 103 of one of the second switchboards 102 (distribution panels). In the communication system 1a as the modified example 1, the switchboard internal device includes the main breaker 110 (circuit breaker), and the termination device 2 is electrically connected to the main breaker 110 (circuit breaker). Specifically, in the communication system 1a as the modified example 1, one of the two termination devices 2 is terminated in the main breaker 110 (circuit breaker) built in the distribution board 102 (distribution board). In the following, one of the two termination devices 2 will be explained. The terminating device 2 is housed in a cladding of one of the main breakers 110. The terminating device 2 is electrically connected to the two primary terminals 111 of the main breaker 110. The main breaker 110 includes two primary terminals 111 that are electrically connected to the two power conductors 9, respectively. That is, the terminating device 2 is electrically connected to the two power conductors 9 via the two primary terminals 111 of the main breaker 110. For example, the termination device 2 maintains electrical connection with the two power conductors 9 even if the main breaker 110 is turned off and the branch breaker 120 is disconnected from the two power conductors 9. Therefore, even if the main breaker 110 is turned off, the termination device 2 can maintain electrical connection with the two power conductors 9. As explained above, the terminating device 2 is provided in the main breaker 110 (distributor internal device) disposed inside the cabinet 103 of the second switchboard 102. If the main breaker 110 is housed in the second switchboard 102 and then electrically connected to the two power conductors 9, the termination device 2 is housed in the cabinet 103 of the second switchboard 102 and electrically connected to the two power conductors 9 . Preferably, the terminating device 2 is electrically connected to the main breaker 110 in the second switchboard 102. With the aforementioned configuration, the main breaker 110 in which the termination device 2 is built is electrically connected to the two power conductors 9, and by this, the termination device 2 is electrically connected to the two through the two primary terminals 111 of the main breaker 110. Power conductor 9. Therefore, the termination device 2 can be electrically connected to the two power conductors 9 without attaching the termination device 2 to the two power conductors 9. The terminating device 2 is preferably built into the main circuit breaker 110 of the second switchboard 102. In this case, even if one of the spaces for accommodating the termination device 2 is not fixed in the second distribution board 102, the main breaker 110 is still housed in the second distribution board 102 and thereby the termination device 2 is accommodated. In the cabinet 103 of the second distribution board 102. Note that the termination device 2 is electrically connected to the two primary terminals 111 of the main breaker 110, but is not limited thereto. The terminating device 2 can be electrically connected to the two secondary terminals 112 of the main breaker 110. In this case, the terminating device 2 can be electrically connected to the two secondary terminals 112 of the closed main breaker 110. A worker closes the main breaker 110, and thereby the termination device 2 can be electrically connected to the two secondary terminals 112 of the main breaker 110 without power being supplied to the two secondary terminals 112. In the above explanation, the internal device of the switchboard is the main circuit breaker, but is not limited thereto. An example of a switchboard internal device may further include a branch circuit breaker 120, and another switchboard internal device for the second switchboard 102 that is electrically coupled to the two secondary terminals 112 of the main breaker 110. The second switchboard 102 can have a current limiting circuit breaker as an internal device of a switchboard configured to limit the maximum value of one of the AC currents I1 through the two power conductors 9 to a specified current value or less. value. For example, the current limiting circuit breaker is electrically connected to the two power conductors 9 and the main breaker 110. When the maximum value of the AC current I1 reaches a prescribed current value, the current limiting circuit breaker disconnects the main circuit breaker 110 from the two power conductors 9 electrically. The terminating device 2 can be built into the current limiting circuit breaker or electrically connected to the current limiting circuit breaker to be electrically connected to the two power conductors 9. (Modified Example 2 in Embodiment 1) A communication system 1b which is a modified example 2 of Embodiment 1 will be explained with reference to FIG. In the communication system 1b of the modified example 2 shown in Fig. 3, a first switchboard 101 (see Fig. 1) and a communication subsystem 10 (see Fig. 1) closer to the first switchboard 101 are not shown. The communication system 1b as a modified example 2 is composed of the communication subsystem 10 and a communication subsystem 10b in the first embodiment. The communication subsystem 10b includes a power line communication device 3 and a termination device 2a. The communication system 1b as the modified example 2 of the embodiment 1 includes the termination device 2a provided inside the cabinet 103 of one of the second distribution boards 102, and is distinguished from the communication system 1a as the modified example 1 by the termination The device 2a is not built into a main breaker 110. The other configuration of the communication system 1b is the same as that of the communication system 1 in the first embodiment. The same elements are assigned the same as the element symbols depicted in Embodiment 1, and the description thereof is omitted as appropriate. In the communication system 1b as a modified example 2, the main breaker 110 (circuit breaker) includes two primary terminals 111 and two secondary terminals 112 that allow electrical connection to the two power conductors 9. The termination device 2a includes two first terminals 201 that permit electrical connection to the two secondary terminals 112, and two second terminals 202 that permit electrical connection to the two first terminals 201 and a load 300. The termination device 2a is configured to be disposed inside the cabinet 103 of the second distribution board 102 (distribution panel). The two primary terminals 111 and the two secondary terminals 112 of the main breaker 110 are disposed inside the cabinet 103 of the second switchboard 102. The termination device 2a includes two second terminals 202 that are electrically connected to the two input terminals of the one-way breaker 120. The branch circuit breaker 120 includes two output terminals that allow electrical connection to the load 300. Therefore, the two secondary terminals 112 of the main breaker 110 will be electrically connected to the load 300 through the termination device 2a and the branch breaker 120. The terminating device 2a is electrically connected to the two secondary terminals 112 of the main breaker 110. When the main breaker 110 is electrically connected between the two primary terminals 111 and the two secondary terminals 112, the terminating device 2a is electrically connected to the two power conductors 9. With the aforementioned configuration, the two first terminals 201 of the terminating device 2a are electrically connected to the two secondary terminals 112 of the main breaker 110, and thereby the terminating device 2a is electrically connected to the power conductor 9. Since each of the two first terminals 201 and the two secondary terminals 112 is a terminal, the direct electrical and mechanical connection between each of the two terminals facilitates maintaining contact reliability between each of the two terminals. Therefore, the reliability of the electrical connection between the terminating device 2a and the main breaker 110 can be enhanced. The termination device 2a can be electrically connected to the two power conductors 9 by electrically connecting the termination device 2a between the main breaker 110 and the branch breaker 120, wherein the termination device 2a is disposed inside the cabinet 103. For example, even in the case where a switchboard internal device such as the main breaker 110 cannot be built in the terminating device 2a, the terminating device 2a can be electrically connected to the two power conductors 9, wherein the terminating device 2a is disposed in the cabinet 103 internal. Note that in the communication system 1b which is the modified example 2 of the embodiment 1, the terminating means 2a can be disposed outside the cabinet 103 of the second distribution board 102. In the communication system 1b as the modified example 2, the main breaker 110 (circuit breaker) in the second distribution board 102 (distribution board) is electrically connected to both ends of the two power conductors 9. The terminating device 2a disposed outside the second switchboard 102 (distribution board) may include two first terminals 201 that allow electrical connection to the main breaker 110 (circuit breaker), and two allowable electrical connections to the load 300 Two terminals 202. In particular, the two first terminals 201 of the termination device 2a can be electrically connected to the two output terminals of the branch circuit breaker 120. In this case, the terminating device 2a is electrically connected to the two power conductors 9 through the branch circuit breaker 120 and the main breaker 110. The two second terminals 202 of the termination device 2a can also be electrically connected to the load 300. In this case, the terminating device 2a can electrically connect one of the output terminals electrically connected to the output terminal of the branch circuit breaker 120 to one of the power lines electrically connected to the load 300. With the foregoing configuration, even in the case where the terminating device 2a is disposed outside the cabinet 103 of the second switchboard 102 (distribution board), the terminating device 2a is still electrically connected to the main breaker 110 (circuit breaker), and thereby Electrically connected to two power conductors 9. Therefore, even in the case where it is impossible to secure a space for storing the terminating device 2a inside the cabinet 103 of the second switchboard 102, the terminating device 2a can be electrically connected to the two power conductors 9. (Modified Example 3 of Embodiment 1) A terminating device 2b in one communication system as a modified example 3 of Embodiment 1 will be explained with reference to Figs. 4A and 4B. 4A and 4B are perspective views of the terminating device 2b. The communication system as the modified example 3 is composed of the communication subsystem 10 (see FIG. 1) in the embodiment 1, and a communication subsystem including a power line communication device (see FIG. 1) and the terminating device 2b. The terminating device 2b is provided with two conductive portions 21 instead of the two connection terminals 200 of the terminating device 2 (see Fig. 1). In the communication system as a modified example 3, one of the main switchboards 110 (circuit breakers) (see FIG. 1) of a second switchboard 102 (distribution board) (see FIG. 1) is electrically connected to two power conductors. 9. The other configuration of the communication system as the modification example 3 is the same as that of the communication system 1 of the first embodiment. The same elements are assigned the same as the element symbols depicted in Embodiment 1, and the description thereof is omitted as appropriate. As shown in FIGS. 4A and 4B, the terminating device 2b includes two conductive portions 21 (contacts) and one of the non-conductive claddings 22. The cladding 22 of the termination device 2b has, for example, a rectangular cube shape. The cladding 22 houses a capacitor and a voltage limiting device. Two conductive portions 21 protrude from the surface of one of the claddings 22. A socket 12 (power socket) is attached to a building structural component such as, for example, a wall. The socket 12 has, for example, two pairs of insertion holes (socket holes) 13. A conductive member corresponding to the insertion hole 13 is provided in the cladding of the socket 12. The conductive portion 21 of the terminating device 2b (inserted into the two insertion holes 13) is in contact with the corresponding conductive member. The conductive member corresponding to the first insertion hole 13 of the pair of insertion holes 13 of the socket 12 is electrically connected to one of the output terminals of the two output terminals of the one-way breaker 120 via a power line. The conductive members corresponding to the second insertion holes 13 of the pair of insertion holes 13 of the socket 12 are electrically connected to the other output terminal of the two output terminals of the branch circuit breaker 120 via the power line. Since the two conductive portions 21 are inserted into the pair of insertion holes 13 of the socket 12, the terminating device 2b can be detachably connected to the socket 12. In the communication system as a modified example 3, the terminating device 2b is configured to be electrically connected to the socket 12 in a detachable manner, and the socket 12 is electrically connected to the main breaker 110 (circuit breaker). The two conductive portions 21 of the terminating device 2b are inserted into one of the pair of sockets 12 into the insertion hole 13 and then contact the corresponding conductive member, so that the terminating device 2b is electrically connected to the main breaker 110. In short, the termination device 2b in the communication system as the modification example 3 can be electrically connected to the two output terminals of the branch circuit breaker 120 in the second distribution board 102. With the aforementioned configuration, when the terminating device 2b is electrically connected to the socket 12, the terminating device 2b can be electrically connected to the two power conductors 9, thereby enabling a worker to easily electrically connect the terminating device 2b to two powers Conductor 9. Note that in the communication system as the modified example 3, the terminating means 2b can be built in the socket 12 by omitting the two conductive portions 21 of the terminating means 2b. In the communication system as the modified example 3, the main breaker 110 (circuit breaker) in the second distribution board 102 (distribution board) can be electrically connected to one end of the two power conductors 9. The terminating device 2b in the communication system as the modified example 3 can be built in the socket 12 electrically connected to the main breaker 110 (circuit breaker). In this case, the cladding 22 of the termination device 2b can be omitted. The terminating device 2b in the communication system as the modified example 3 can be accommodated, for example, in a case of the socket 12. For example, in the case where the terminating device 2b is housed in the casing of the socket 12, the terminating device 2b needs to be electrically connected to the conductive member corresponding to the insertion hole 13 of one of the sockets 12. The terminating device 2b is electrically connected to the main breaker 110 through two output terminals of the branch circuit breaker 120 (see Fig. 1). With the foregoing configuration, since the terminating device 2b is built into the socket 12, it is not necessary to provide the terminating means 2b outside the socket 12 when the terminating device 2b is electrically connected to the two power conductors 9 through the socket 12. In the communication system as the modified examples 1 and 2 of the first embodiment, the respective terminating devices are disposed inside the cabinet 103 of the second power board 102, but are not limited thereto. One of the two termination devices closer to the first distribution board 101 may be disposed inside the cabinet of the first distribution board 101 or disposed inside one of the cabinets accommodated in the first distribution board 101. in. (Embodiment 2) A communication system 1c according to Embodiment 2 will be explained with reference to FIG. The communication system 1c includes two communication subsystems 10c, each of which includes a power line communication device 3 and a termination device 2c in the communication system 1 according to the first embodiment. In the communication system 1c, the configuration of the terminating device 2c is different from the configuration of the terminating device 2 in the communication system 1 according to the embodiment 1. The other configuration of the communication system 1c is the same as that of the communication system 1 according to the embodiment 1. The same elements are assigned the same as the element symbols depicted in Embodiment 1, and the description thereof is omitted as appropriate. Each of the two termination devices 2c has two cores 8 (two second cores) corresponding to two power conductors 9 and a conductor wire 82. Each of the two cores 8 has a ring shape and is made of a magnetic material such as, for example, ferrite. One of the two power conductors 9 of the first power conductor 9 (L1 phase) is inserted into one of the through holes 81 of one of the first cores 8 of the two cores 8. The second power conductor 9 (L2 phase) of one of the two power conductors 9 is inserted into one of the through holes 81 of one of the two cores 8 of the second core 8. The conductor wires 82 are inserted into the through holes 81 of both the cores 8. Portions of the two cores 8 and conductor wires 82 are housed in, for example, one of the non-conducting housings, with the two power conductors 9 being inserted into the through holes 81 of the two cores 8. In the present embodiment, two of the two cores of the two power line communication devices 3 are two first cores. Each of the two termination devices 2c serves as an inductive coupling coupler for transmitting a communication signal S1 as an AC current between the two power conductors 9. For example, when the AC current for transmitting the communication signal S1 is superimposed on the AC current I1 passing through one of the two power conductors 9 (L1 phase), the induced current is transmitted through one of the two cores 8 of the first core 8 Flow through the conductor wires 82. An induced field occurs from the second core 8 of the two cores 8 by the induced current through the conductor wires 82, and the AC current for transmitting the communication signal S1 is superimposed on the second core 8 through one of the two power conductors 9 The second current I1 of the power conductor 9 (L2 phase). That is, each of the two termination devices 2c magnetically couples the two power conductors 9 by inductive coupling, thereby reducing the impedance between the two power conductors 9 in one of the frequency bands of the communication signal S1. In particular, the two termination means 2c cause the impedance between the two power conductors 9 in the frequency band of the communication signal S1 to be less than the impedance between the two power conductors 9 at one of the frequencies of the AC voltage V1. When the terminating device 2c magnetically couples the two power conductors 9 by inductive coupling, a worker can attach the terminating devices 2c only by inserting the power conductors 9 and a conductor wire 82 into the through holes 81 of the core 8. To two power conductors 9. Therefore, the operation time of attaching the terminating device 2c to one of the two power conductors 9 can be shortened. When each core 8 is specifically a split core, the worker can easily attach the core 8 to the two power conductors 9 that are installed. In this case, there is an advantage that the worker does not have to stop the supply of power to the two power conductors 9 when the terminating device 2c is attached to the two power conductors 9. (Modified Example of Embodiment 2) A communication system 1d which is one of the modified examples of Embodiment 2 will be explained with reference to FIG. In Fig. 6, the first switchboard 101 (see Fig. 5) and the communication subsystem 10c (see Fig. 5) on one side of the first switchboard 101 are not shown. The communication system 1d as a modified example further includes a case 11 enclosing two cores 8 (two second cores). The other configuration of the communication system 1d is the same as that of the communication system 1c according to the embodiment 2. The same elements are assigned the same as the element symbols depicted in Embodiment 2, and the description thereof is omitted as appropriate. The cladding 11 is made of, for example, a non-conductive synthetic resin material. The cladding 11 has a rectangular box shape and accommodates two cores 8. The cladding 11 further houses a conductor wire 82. The two cores 8 will be attached to two power conductors 9, two of which are housed in the cladding 11. With the configuration of the communication system 1d as a modified example, since the two cores 8 are housed in the casing 11, the two cores 8 are attached as compared with the case where two of the cores 8 are housed in the respective casings. The number of components required to the two power conductors 9 is reduced. The conductor wires 82 are preferably housed in the cladding 11 and are thereby protected. Note that the enclosure 11 can be configured to accommodate two cores 8, conductor wires 82, two cores 4, and portions of a signal conductor 6. With this configuration, the cladding 11 can accommodate two cores 8, conductor wires 82, two cores 4, and portions of signal conductors 6. Compared to the case where two cores 8 and conductor wires 82 are housed in one housing and portions of the two cores 4 and signal wires 6 are accommodated in the other housing, the two are reduced by the cladding 11 The number of components required for the core 8 and the two cores 4 to be attached to the two power conductors 9. Note that Embodiments 1 and 2 (including modified examples) can be combined as appropriate. For example, the termination device 2c for inductive coupling in the communication system 1c according to Embodiment 2 may be disposed inside the cabinet 103 of the second switchboard 102 (see FIG. 6), or built into a switchboard internal device (such as In a main breaker 110) (see Figure 1). The terminating means 2c for inductive coupling can be connected to two output terminals or two input terminals (see Fig. 1) of a switchboard internal device such as a branch circuit breaker 120. The termination device 2c for inductive coupling can be connected to a socket 12 (see Figure 4B). (Brief) As understood from the foregoing embodiments, the communication system 1, 1a, 1b, 1c, 1d according to a first aspect comprises a power line communication device 3 and two termination devices 2, 2a, 2b, 2c. The power line communication device 3 is configured to superimpose a communication signal S1 on the AC power supplied to the two power conductors 9. The two termination devices 2, 2a, 2b, 2c are configured to terminate a transmission line of the communication signal S1 on the two power conductors 9. Each of the power line communication devices 3 has two cores 4 corresponding to the two power conductors 9 and one of the signal wires 6 inserted into the respective through holes 41 of the two cores 4. Each of the power line communication devices 3 has a first function for transmitting a communication signal S1 through the signal conductor 6 and a communication signal S1 for transmitting a communication signal from the other power line communication device 3 of the power line communication device 3 through the signal conductor 6. A second function. The respective cores 4 of the power line communication devices 3 are arranged between the two termination devices 2 along two power conductors 9. The two termination devices 2 are configured such that the impedance between the two power conductors 9 in one of the frequency bands of the communication signal S1 is less than the two power conductors 9 at a frequency of one of the AC voltages applied across the two power conductors 9. Impedance between. By virtue of the first aspect, the two termination means 2, 2a, 2b, 2c can make the impedance between the two power conductors 9 in the frequency band of the communication signal S1 smaller than the impedance at the frequency of the AC voltage. The two termination devices 2, 2a, 2b, 2c can suppress the attenuation of the communication signal S1 to reduce the impedance of the transmission line of the communication signal S1 by terminating the transmission line of the communication signal S1 on the two power conductors 9. The communication systems 1, 1a, 1b, 1c, 1d can thus improve the reliability of power line communication. In the communication system 1, 1a, 1b, 1c, 1d in the first aspect, each of the two termination devices comprises a capacitor 7 configured to be electrically connected between the two power conductors 9 (hereinafter Called a "second state"). By virtue of the second aspect, the capacitor 7 in the termination means 2, 2a, 2b, 2c allows the impedance between the two power conductors 9 in the frequency band of the communication signal S1 to be less than the impedance at the frequency of the AC voltage V1. In the communication system 1, 1a, 1b, 1c, 1d in the first or second aspect, each of the two termination devices 2, 2a, 2b, 2c includes a pressure limiting device 71. The voltage limiting device 71 is configured to limit the voltage across the two power conductors 9 to a prescribed voltage or less when a surge voltage exceeding a prescribed voltage is applied across the two power conductors 9 (hereinafter referred to as a "third Aspect"). By virtue of the third aspect, even if a surge voltage exceeding a prescribed voltage is applied across the two power conductors 9 by an electric shock or the like, the voltage limiting device 71 limits the voltage across the two power conductors 9 to a prescribed voltage or less. Voltage. Therefore, the voltage limiting device 71 can prevent the surge voltage across the prescribed voltage from being applied across the capacitor 7 (or the electronic circuit or the like) electrically connected to the two power conductors 9. When a surge voltage exceeding a prescribed voltage is applied across two power conductors 9 by an electric shock or the like, the voltage limiting device 71 can suppress the occurrence of dielectric collapse between the two power conductors 9. The voltage limiting device 71 prevents a surge voltage exceeding a prescribed voltage from being applied to the first switchboard 101 and the second switchboard 102. In the communication system 1c, 1d in the first or second aspect, each of the two termination devices 2c includes: two termination cores 8, which are different from the core 4 of the power line communication device 3; and a conductor wire 82. It is inserted into the respective through holes 81 of the termination core 8 (hereinafter referred to as a "fourth aspect"). In one example, the conductor wires 82 form a closed loop separately, and each of the termination cores 8 is a ring core. By virtue of the fourth aspect, the two termination means 2c can reduce the impedance between the two power conductors 9 in the frequency band of the communication signal S1 by magnetically coupling the two power conductors 9 by means of the two termination cores 8 and conductor wires 82. Therefore, the impedance between the two power conductors 9 in the frequency band of the communication signal can be reduced without attaching the termination device 2 to the two power conductors 9. When each termination core 8 is a split core, the termination core 8 can be attached to the installed two power conductors 9, and thus the operating time for insertion of the two power conductors 9 can be omitted. In the communication system 1d in the fourth aspect, each of the two terminating means 2c further includes a casing 11 accommodated for the two terminating cores 8 (hereinafter referred to as a "fifth aspect"). By way of the fifth aspect, since the two termination cores 8 can be housed in the cladding 11, the two termination cores 8 are attached to the case where two of the termination cores 8 are housed in the respective housings. The number of components required for the two power conductors 9 is reduced. In the communication systems 1a, 1b of any of the first to fourth aspects, one of the two termination devices 2, 2a, 2b, 2c terminates in the second distribution board 102 (distribution) One of the panels 103 inside the cabinet). The second distribution board 102 (distribution board) is connected to one end of the two power conductors 9 (hereinafter referred to as a "sixth aspect"). By virtue of the sixth aspect, the terminating means 2, 2a can be electrically connected to the two power conductors 9 without attaching the terminating means 2, 2a to the two power conductors 9. In the communication systems 1a, 1b in the sixth aspect, the terminating means 2, 2a disposed inside the cabinet 103 allow electrical connection to a main breaker 110 (circuit breaker). The main breaker 110 (circuit breaker) is included in the switchboard 102 as a switchboard internal device. This configuration is hereinafter referred to as a "seventh aspect". By virtue of the seventh aspect, the termination devices 2, 2a can be electrically connected to the two power conductors 9 without attaching the termination devices 2, 2a to the two power conductors 9. In the communication system 1a in the seventh aspect, the terminating device 2 disposed inside the cabinet 103 is built in the main breaker 110 (circuit breaker) (hereinafter referred to as an "eighth aspect"). By way of the eighth aspect, even if the second switchboard 102 is not provided with a space for accommodating the termination device 2, the main breaker 110 is still housed in the second switchboard 102, and thereby the termination device 2 is accommodated In the cabinet 103 of the second distribution board 102. In the communication system 1b in the seventh aspect, the terminating device 2a disposed inside the cabinet 103 has two first terminals 201 that allow electrical connection to the two secondary terminals 112 of the main breaker 110 (circuit breaker), And allowing the second terminal 202 to be electrically connected to the two first terminals 201 and one load 300. The main breaker 110 (circuit breaker) further has two primary terminals 111 that are electrically connected to the two power conductors 9. Hereinafter, this configuration is hereinafter referred to as a "ninth aspect". By way of the ninth aspect, the termination device 2a can be electrically connected to the two power conductors 9 even when the termination device 2a cannot be built into a switchboard internal device, such as a main breaker 110, wherein the termination device 2a It is disposed inside the cabinet 103. In the communication system of any of the first to fourth aspects, one of the two termination devices (configured to be disposed outside the cabinet 103 of one of the second distribution boards 102 (distribution boards)) has Allowing electrical connection to two first terminals 201 of one of the main circuit breakers 110 (circuit breakers) of the second switchboard 102 (distribution board), and allowing electrical connection to the two first terminals 201 and one of the loads 300 Second terminals 202. The main breaker 110 (circuit breaker) is electrically connected to one end of the two power conductors 9. This configuration is hereinafter referred to as a "tenth aspect". By virtue of the tenth aspect, even when the cabinet 103 of the second switchboard 102 cannot have a space therein for accommodating the terminating device, the terminating device can be electrically connected to the two power conductors 9. In the communication system of any of the first to fourth aspects, one of the two termination devices 2, 2a, 2b, 2c is configured to be electrically connected to a socket 12 in a detachable manner. The socket 12 is electrically connected to one of the main breakers 110 (circuit breakers) in a second switchboard 102 (distribution panel). The main breaker 110 (circuit breaker) is electrically connected to one end of the two power conductors 9. This configuration is hereinafter referred to as an "eleventh aspect". By way of the eleventh aspect, when the terminating device 2b is electrically connected to the socket 12, the terminating device 2b can be electrically connected to the two power conductors 9, thereby enabling a worker to easily electrically connect the terminating device 2b to two Power conductors 9. In the communication system of any of the first to fourth aspects, one of the two termination devices 2, 2a, 2b, 2c is built into a socket 12, and the socket 12 allows electrical connection to a One of the main circuit breakers 110 (circuit breakers) in the distribution board 102 (distribution board). The main breaker 110 (circuit breaker) is electrically connected to one end of the two power conductors 9. This configuration is hereinafter referred to as a "twelfth aspect". With the twelfth aspect, since the terminating device is built into the socket 12, it is not necessary to provide the terminating means outside the socket 12 when the terminating device is electrically connected to the power conductor 9 through the socket 12. The terminating means 2, 2a, 2b, 2c are terminated as one of the thirteenth aspects as the terminating means in the communication system 1. The terminating means 2, 2a, 2b, 2c are configured to terminate a transmission line of one of the communication signals S1 superimposed on the AC power passing through the two power conductors 9 by each of the power line communication means 3. The terminating means 2, 2a, 2b, 2c are also configured such that the impedance between the two power conductors 9 in one of the frequency bands of the communication signal S1 is less than the frequency of one of the AC voltages applied across the two power conductors 9. The impedance between the power conductors 9. With the thirteenth aspect, the termination devices 2, 2a, 2b, 2c can improve the reliability of power line communication. According to a fourteenth aspect, the communication subsystems 10, 10b, 10c comprise a power line communication device 3 and termination devices 2, 2a, 2b, 2c. The power line communication device 3 is configured to superimpose one communication signal S1 to be transmitted on the AC power passing through the two power conductors 9 through a signal conductor 6 and two cores 4; and also through the signal conductor 6 and the two cores 4 receiving an incoming communication signal S1 superimposed on the AC power. The terminating means 2, 2a, 2b, 2c are electrically connected to the two power conductors 9 to terminate one of the communication lines S1 superimposed on the AC power. The terminating means 2, 2a, 2b, 2c are configured such that the impedance between the two power conductors 9 in one of the frequency bands of the communication signal S1 is less than the frequency of one of the AC voltages applied across the two power conductors 9. The impedance between the power conductors 9. With the fourteenth aspect, the termination devices 10, 10b, 10c can improve the reliability of power line communication. While the foregoing has been described in terms of the preferred embodiments and/or other examples, it is understood that various modifications can be made therein and the subject matter disclosed herein can be implemented in various forms and examples, and the like can be applied to many applications. I have only described some of them in this article. The following claims are intended to cover any and all modifications and variations that fall within the true scope of the invention.

1‧‧‧Communication system
1a‧‧‧Communication system
1b‧‧‧Communication system
1c‧‧‧Communication system
1d‧‧‧Communication system
2‧‧‧ termination device
2a‧‧‧ Termination device
2b‧‧‧ termination device
2c‧‧‧ Termination device
3‧‧‧Power line communication device
4‧‧‧ core
5‧‧‧ Coupler
6‧‧‧Signal wires
7‧‧‧ capacitor
8‧‧‧ core (terminating core)
9‧‧‧Power conductors (two power conductors)
10‧‧‧Communication subsystem
10b‧‧‧Communication subsystem
10c‧‧‧Communication subsystem
11‧‧‧Encasement
12‧‧‧ socket
13‧‧‧Insert hole
21‧‧‧Electrical part
22‧‧‧Encasement
30‧‧‧Communication circuit
31‧‧‧Power line communication device
32‧‧‧Power line communication device
41‧‧‧through hole
51‧‧‧ Coupler
52‧‧‧ Coupler
61‧‧‧Signal wires
62‧‧‧Signal wires
71‧‧‧Limiting device
81‧‧‧through hole
82‧‧‧Conductor wire
100‧‧‧Power supply
101‧‧‧First switchboard
102‧‧‧Second switchboard (distribution board)
103‧‧‧ cabinet
110‧‧‧Main circuit breaker (internal switchboard, circuit breaker)
111‧‧‧Primary terminal
112‧‧‧Secondary terminals
120‧‧‧ branch circuit breaker
200‧‧‧Connecting terminal
201‧‧‧First terminal
202‧‧‧second terminal
300‧‧‧load
301‧‧‧Communication circuit
302‧‧‧Communication circuit
I1‧‧‧ Current
L1‧‧‧ phase
L2‧‧‧ phase
S1‧‧‧ communication signal
V1‧‧‧ voltage

1 is a communication system according to Embodiment 1 of the present invention; FIG. 2 is a part of a communication system as a modified example 1 according to Embodiment 1 of the present invention; FIG. 3 is a view showing Embodiment 1 according to the present invention; FIG. 4A is a perspective view of one of the termination devices of the communication system according to Embodiment 1 of the present invention, and FIG. 4B is a communication system. 1 is a perspective view of a termination device connected to a socket; FIG. 5 illustrates a communication system according to Embodiment 2 of the present invention; and FIG. 6 illustrates a communication system as a modified example of Embodiment 2 of the present invention. section.

Claims (14)

A communication system comprising: a power line communication device configured to superimpose a communication signal on AC power supplied to two power conductors, two termination devices, etc. configured to communicate the communication signal a transmission line terminating on the two power conductors, wherein each of the power line communication devices has two cores corresponding to the two power conductors, and one of the signal wires of the respective through holes of the two cores Each of the power line communication devices has a first function for transmitting the communication signal through the signal conductor and a communication signal for transmitting another power line communication device from the power line communication device through the signal conductor a second function, wherein the respective cores of the power line communication devices are disposed between the two termination devices along the two power conductors, and the two termination devices are configured to be in one of the communication signals The impedance between the two power conductors in the frequency band is less than the impedance between the two power conductors at a frequency across one of the AC voltages applied by the two power conductors. The communication system of claim 1, wherein each of the two termination devices comprises a capacitor configured to electrically connect between the two power conductors. The communication system of claim 1 or 2, wherein each of the two termination devices includes a voltage limiting device configured to span the two when a surge voltage exceeding a prescribed voltage is applied across the two power conductors The voltage of the power conductors is limited to the specified voltage or less. The communication system of claim 1 or 2, wherein each of the two termination devices comprises: two termination cores, which are different from the cores of the power line communication devices; and a conductor wire inserted into the Wait for the core to be in the respective through hole. The communication system of claim 4, wherein each of the two termination devices further comprises a cladding housing the corresponding two termination cores. The communication system of any one of claims 1 or 2, wherein one of the two termination devices is disposed within a cabinet of a power distribution panel that is coupled to one of the two power conductors. The communication system of claim 6, wherein the terminating means disposed inside the cabinet allows electrical connection to a circuit breaker, the circuit breaker being included as a switchboard internal device in the switchboard. The communication system of claim 7, wherein the terminating device disposed inside the cabinet is built in the circuit breaker. The communication system of claim 7, wherein the termination device disposed inside the cabinet has two first terminals that allow electrical connection to two secondary terminals of the circuit breaker and allow electrical connection to the two first terminals And two second terminals of a load, the circuit breaker further having two primary terminals electrically connected to the two power conductors. The communication system of any one of claims 1 or 2, wherein one of the two termination devices configured to be disposed outside a cabinet of a power distribution panel has a termination device that allows electrical connection to one of the power distribution boards Two first terminals of the circuit breaker and two second terminals that are electrically connected to the two first terminals and a load, the circuit breaker being electrically connected to one end of the two power conductors. The communication system of any one of claims 1 or 2, wherein one of the two termination devices is configured to be electrically connected to a socket in a detachable manner, the socket being electrically connected to a switchboard A circuit breaker electrically connected to one end of the two power conductors. The communication system of any one of claims 1 or 2, wherein one of the two termination devices is built into a socket that allows electrical connection to one of the circuit breakers of a switchboard, the circuit breaker One end of the two power conductors is electrically connected. A termination device for use as a termination device in a communication system according to any one of claims 1 to 12. A communication subsystem comprising at least one power line communication device of a power line communication device in a communication system of claim 1 and a termination device as claimed in claim 13.