JP2016219994A - Power line communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power line communication system capable of improving communication quality in power line communication with a high voltage distribution line as a transmission path.SOLUTION: A power line communication system 1 includes: a high voltage distribution line 4 extended from a secondary side of a transformer 3S in a substation 2; a first power line modem 6S connected to a first connection point on the high voltage distribution line 4; power line modems 6A, 6B connected to a second connection point on the high voltage distribution line 4 positioned more on a downstream side than the first connection point when viewed from the substation 2, which communicate via the high voltage distribution line with the first power line modem 6S; and a signal regulator 15 provided on the high voltage distribution line 4, which includes magnetic cores 15a, 15b, 15c provided more on an upstream side than the first connection point. When a phase advance capacitor 11 is provided in the substation 2, an impedance at the substation 2 side to which the phase advance capacitor 11 is connected becomes low, and the impedance at the substation 2 side is increased by the signal regulator 15. Thus, it is possible to suppress the attenuation of a signal flowing to the downstream side of the high voltage distribution line 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power line communication system, and more particularly, to a power line communication system suitable for a power distribution control system for controlling a switch on a high voltage distribution line and using the high voltage distribution line as a communication medium.

  Electricity is indispensable not only for ordinary households, but also for industrial fields such as factories and offices, and social infrastructure such as hospitals and transportation, and damage due to power outages is immeasurable. The shorter the time required from power failure to recovery, the less loss society suffers, so electric power companies have attempted to advance the power distribution system (see, for example, Patent Document 1). Centralized control of distribution routes is one part of this, and high-voltage distribution lines that are supplied by electric power companies are able to distribute multiple power distributions with the aim of minimizing the occurrence of power outages in other areas. Designed to be the root. A switch (route switch) is provided at the branch point of each distribution route, and the power failure area can be minimized by switching the distribution route.

  FIG. 5 is a block diagram showing a distribution system of the high-voltage distribution line.

  As shown in FIG. 5, the high-voltage distribution line 22 extends from the substation 21 while branching to a plurality of systems and supplies power to consumers. Since the high-voltage distribution line 22 is an important infrastructure, the wiring route is duplicated and looped for the purpose of redundancy, and even if a short circuit or ground fault occurs, the necessary minimum is achieved by switching the distribution system. It can be done with a power outage in the area. The switch 23 for connecting / disconnecting the distribution system is remotely controlled from the monitoring center of the electric power company. As a means for transmitting the control signal, a PLC (Power Line Communication) for superimposing a high-frequency signal on the high-voltage distribution line is used. Used.

  The high voltage of 6600 V of the high-voltage distribution line 22 is reduced to 200/100 V by the transformer 24, and the small consumer 26 such as a detached house is 200/100 V through the low-voltage distribution line 25 connected to the secondary side of the transformer 24. Power is supplied. On the other hand, high-voltage consumers 27 such as apartment houses and factories are supplied with high voltage as they are, and are supplied with electric power through step-down transformers installed in electric rooms or cubicles.

JP-A-9-23583

  Since the high-voltage distribution line is not designed as a communication medium, there are the following problems for ensuring stable communication. That is, when there is an electrical facility using a motor such as an elevator or a pump in the substation, a phase advance capacitor for compensating the phase may be provided in the high voltage distribution line in order to improve the power factor. Since the phase-advancing capacitor appears to be low impedance at the frequency of the PLC signal, the impedance on the substation side is lower when viewed from the power line modem connected to the high-voltage distribution line near the substation, and the PLC that flows downstream of the high-voltage distribution line The signal level is attenuated. Therefore, there is a problem in that a sufficient level of PLC signal cannot be delivered to the counterpart power line modem on the high-voltage distribution line, and communication quality deteriorates.

  In order to cover the attenuation of the PLC signal, for example, it is possible to provide a repeater device that relays the PLC signal in the middle of the communication path. Since there is a danger, it is necessary to make a power outage when performing installation work, and there are also problems such as increased installation costs and high hurdles in installation.

  Therefore, the objective of this invention is providing the power line communication system which can improve the communication quality of the power line modem which performs power line communication via a high voltage distribution line.

  In order to solve the above problems, a power line communication system according to the present invention includes a high voltage distribution line extending from a secondary side of a transformer in a substation, and a first power line modem connected to a first connection point on the high voltage distribution line. , Connected to a second connection point on the high-voltage distribution line located downstream from the first connection point when viewed from the substation, and the first power line modem and power line communication via the high-voltage distribution line And a signal conditioner including at least one magnetic core provided on an upstream side of the first connection point on the high-voltage distribution line.

  According to the present invention, since the impedance of the high-voltage distribution line on the substation side is increased by the signal conditioner as viewed from the signal injection point of the first power line modem, the PLC signal sent to the downstream side of the high-voltage distribution line Signal level attenuation can be suppressed. Therefore, the communication quality between a pair of power line modems on the high voltage distribution line can be ensured.

  Preferably, the power line communication system according to the present invention further includes a switch provided on the high-voltage distribution line, and the second power line modem transmits and receives a control signal for controlling the switch. According to this configuration, in the power distribution control system that controls the switch on the high-voltage distribution line, the communication quality between the pair of power line modems that transmit and receive the control signal of the switch can be ensured.

  The power line communication system according to the present invention further includes a high voltage lead line provided in the substation, one end of which is connected to the high voltage distribution line, and a phase advance capacitor connected to the high voltage lead line, It is preferable that it is provided downstream from the connection point of the high-voltage lead-in wire. When a phase advance capacitor is connected to the high-voltage lead-in wire connected to the high-voltage distribution line, the impedance of the high-voltage distribution line on the substation side is low as viewed from the signal injection point of the first power line modem. Thus, the signal level of the PLC signal sent to the downstream side of the high-voltage distribution line is attenuated. In contrast, by providing a signal conditioner, the impedance on the substation side can be increased, and the communication quality of the power line modem on the high-voltage distribution line can be ensured.

  In the present invention, the high-voltage distribution line has first to third distribution lines, and the signal conditioner is provided to the first to third magnetic cores provided on the first to third distribution lines, respectively. It is preferable to contain. According to this configuration, the effect of the signal conditioner can be exhibited regardless of which of the first to third distribution lines is used as the transmission line for power line communication, and the flexibility in constructing the power line network is increased. be able to.

  ADVANTAGE OF THE INVENTION According to this invention, the power line communication system which can improve the communication quality in the power line communication which uses a high voltage distribution line as a transmission line can be provided.

FIG. 1 is a block diagram showing a configuration of a power line communication system according to a preferred embodiment of the present invention. FIG. 2 is a schematic perspective view showing an example of the structure of the magnetic cores 15a, 15b, and 15c. FIG. 3 is a diagram for explaining the operation of the signal conditioner, and shows a case where there is no signal conditioner. FIG. 4 is a diagram for explaining the operation of the signal conditioner, and shows a case where the signal conditioner is provided. FIG. 5 is a block diagram showing a distribution system of the high-voltage distribution line.

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

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

  As shown in FIG. 1, the power line communication system 1 includes a high-voltage distribution line 4 extending from a transformer 3S in a substation 2, switches 5A and 5B provided at appropriate positions on the high-voltage distribution line 4, respectively, Power line modems 6 </ b> A, 6 </ b> B, and 6 </ b> S that transmit and receive PLC signals via the electric wires 4 are provided.

  The high-voltage distribution line 4 is a three-phase three-wire distribution line having a line voltage of 6600 V, and includes first to third distribution lines 4a to 4c. Small consumer homes 9A and 9B such as detached houses are supplied with a low voltage of 200V or 100V obtained by stepping down a high voltage of 6600V by transformers 3A and 3B through low voltage distribution lines 8A and 8B. Although not shown, a high voltage of 6600 V is directly supplied to large-scale customer facilities such as apartment houses. The transformers 3A and 3B are, for example, pole-mounted transformers installed on a power pole on which the high-voltage distribution line 4 is wired, and the primary terminal thereof is any two of the three distribution lines 4a, 4b, and 4c. Each is connected to a book.

  The power line modems 6 </ b> A, 6 </ b> B, 6 </ b> S are connected to the high voltage distribution line 4 via the coupler 7, and can communicate with each other via the high voltage distribution line 4. The power line modem 6S (first power line modem) is installed, for example, in the monitoring center of the substation 2, and the connection points (first connection points) with the high voltage distribution lines 4 are the power line modems 6A, 6B ( It is on the upstream side (substation 2 side) of the connection point (second connection point) with the high-voltage distribution line 4 of the second power line modem). For example, a PLC signal transmitted from the power line modem 6S in the monitoring center of the substation 2 is sent to the power line modems 6A and 6B as a control signal for controlling the switches 5A and 5B. In power line communication, a frequency band of 10 k to 450 kHz is used. The configuration of the coupler 7 is not particularly limited, and may be a capacitive coupling method or an inductive coupling method (clamp coupler).

  When there is an electrical facility using a motor such as an elevator or a pump in the substation 2, a phase advance capacitor 11 is connected to the high-voltage lead-in wire 10 branched from the high-voltage distribution line 4 in order to improve the power factor of the motor. Since the phase advance capacitor 11 looks like a low impedance at the frequency of the PLC signal, it is as described above that power line communication is adversely affected.

  In the present embodiment, a signal conditioner 15 is provided on the high-voltage distribution line 4. The signal conditioner 15 is provided on the transformer 3S side of the substation 2 with respect to the connection point CP of the power line modem 6S. The signal conditioner 15 includes first to third magnetic cores 15a, 15b, and 15c installed on the distribution lines 4a, 4b, and 4c, respectively. That is, the first magnetic core 15a is provided in the distribution line 4a, the second magnetic core 15b is provided in the distribution line 4b, and the third magnetic core 15c is provided in the distribution line 4c. As described above, the reason why the magnetic cores are provided in all the three distribution lines 4a, 4b, 4c constituting the high-voltage distribution line 4 is that the pair of signal terminals of the power line modems 6A, 6B, 6S constitute the high-voltage distribution line 4. This is because the PLC signal can be picked up even if connected to any of the three distribution lines 4a to 4c.

  FIG. 2 is a schematic perspective view showing an example of the structure of the magnetic cores 15a, 15b, and 15c.

  As shown in FIG. 2, the magnetic cores 15a, 15b, and 15c are so-called two-divided toroidal cores, and are divided in half by a plane including a cylindrical (annular) central axis (Y-axis). The first core portion 16a and the second core portion 16b include a through hole 16c through which a power line (cable) can be inserted in the Y-axis direction. The material of the magnetic core is not particularly limited, but is preferably made of a magnetic material such as ferrite. The 1st core part 16a and the 2nd core part 16b are accommodated in the resin case etc. which are not illustrated, and are fixed to a cylindrical shape. And only a power line is inserted in the hollow part of each magnetic core 15a, 15b, 15c. Thus, the installation of the magnetic core for the lead-in wires 10a to 10c is very simple.

  The magnetic cores 15a, 15b, and 15c may be the same as the coupler 7 (clamping coupler) for connecting the pair of signal terminals of the power line modems 6A, 6B, and 6S to the high-voltage distribution line 4. That is, the same product as the coupler 7 can be used as the magnetic cores 15a, 15b, and 15c. According to this, the cost of the whole system can also be reduced by unifying parts.

  3 and 4 are diagrams for explaining the operation of the signal conditioner 15. FIG. 3 shows a case where the signal conditioner 15 is not provided, and FIG. 4 shows a case where the signal conditioner 15 is provided. 3 and 4 show only the power line modem 6B, and the illustration of the power line modem 6A is omitted.

  As shown in FIG. 3, when the phase advance capacitor 11 is connected to the high voltage lead-in wire 10, the phase advance capacitor 11 appears to have a low impedance at the frequency of the PLC signal, so that the substation is viewed from the connection point CP of the power line modem 6S. The impedance of the high-voltage distribution line 4 on the second side becomes lower, and most of the PLC signal flows into the substation 2 side, and the level of the PLC signal flowing downstream of the high-voltage distribution line 4 is attenuated. Therefore, for example, when a PLC signal is transmitted from the power line modem 6S to the power line modem 6B through the high-voltage distribution line 4, a sufficient level of PLC signal cannot be delivered from the power line modem 6S to the power line modem 6B, and communication quality deteriorates.

  On the other hand, as shown in FIG. 4, when the signal conditioner 15 including the magnetic cores 15a to 15c is provided on the high voltage distribution line 4 at the illustrated position, the magnetic core has high impedance with respect to the frequency of the PLC signal. When viewed from the connection point CP of the power line modem 6S, the impedance of the high voltage distribution line 4 on the substation 2 side is increased, the PLC signal flowing upstream of the high voltage distribution line 4 is suppressed, and conversely the PLC signal flowing downstream is strong. Become. Thereby, since the PLC signal reaches the power line modem 6B from the power line modem 6S, the communication quality between the power line modem 6S and the power line modem 6B can be ensured.

  Since the influence of the low impedance due to the phase advance capacitor 11 increases as the connection point of the power line modem 6S approaches the substation 2, in the configuration of FIG. 3 in which the signal conditioner 15 is not provided, the power line is suppressed in order to suppress the influence of the low impedance. The connection point of the modem 6S needs to be installed sufficiently far from the substation 2, and it is necessary to provide a dedicated line for controlling the power line modem 6S far from the substation 2. However, when the signal conditioner 15 is provided on the high-voltage distribution line 4 on the substation 2 side from the connection point CP of the power line modem 6S, the distance from the substation 2 to the connection point CP of the power line modem 6S may be reduced. This is possible, and a dedicated line for controlling the power line modem 6S is unnecessary, and a monitoring center in which the power line modem 6S is installed can be provided in the substation 2.

  As described above, a blocking filter is also known as a device for attenuating a signal on a power line. However, the blocking filter is a device for sufficiently attenuating (substantially blocking) the signal of the power line modem installed in the consumer so that it is not transmitted to other systems or neighbors. Is to be installed. On the other hand, the signal conditioner 15 according to the present embodiment is installed in the same network, and rather than attenuating the signal, the direction opposite to the installation position of the signal conditioner 15 as viewed from the signal injection point. The purpose is to make it easy for signals to travel as far as possible over a network that spreads over the network, and the installation is easy with a very simple structure. Thus, the signal conditioner 15 differs from the blocking filter in its intended purpose, installation location, and operational effect.

  As described above, in the power line communication system 1 according to the present embodiment, the signal conditioner 15 in which the impedance of the high-voltage distribution line 4 on the substation 2 side from the signal injection point of the power line modem 6S includes the magnetic cores 15a, 15b, 15c. Therefore, the attenuation of the PLC signal flowing on the high voltage distribution line 4 can be suppressed. Therefore, the communication quality between a pair of power line modems on the high voltage distribution line 4 can be ensured.

  In addition, since the signal conditioner 15 is simple (passive element), it is highly reliable and can be installed without a power outage. Therefore, it is easier to install than conventional repeater devices and blocking filters. It is easy to obtain approval and the introduction cost can be kept low.

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

  For example, in the above embodiment, the magnetic core is provided in all of the distribution lines 4a, 4b, 4c constituting the high-voltage distribution line 4. However, the present invention is not limited to such a configuration. For example, in FIG. The magnetic cores 15a and 15b may be provided in the distribution lines 4a and 4b used as the signal transmission path, and the magnetic core 15c on the distribution line 4c may be omitted. Or any one of magnetic core 15a, 15b may be sufficient, and also only magnetic core 15c may be sufficient. That is, it is only necessary that at least one distribution line is provided with a magnetic core.

  Moreover, in the said embodiment, although the case where the element which reduces the impedance of the high voltage distribution line 4 was the phase-advancing capacitor 11 was mentioned as an example, this invention is not limited to this and targets various elements. Can do.

DESCRIPTION OF SYMBOLS 1 Power line communication system 2 Substation 3A, 3B, 3S Transformer 4 High voltage distribution line 4a 1st distribution line 4b 2nd distribution line 4c 3rd distribution line 5A, 5B Switch 6A Power line modem 6B Power line modem 6S Power line modem 7 Coupler 8A, 8B Low voltage distribution line 9A, 9B Customer's house 10 High voltage service line 10a-10c Service line 11 Phase advance capacitor 15 Signal conditioner 15a, 15b, 15c Magnetic core 16a First core part 16b Second core part 16c Through hole 21 Substation 22 High voltage distribution line 23 Switch 24 Transformer 25 Low voltage distribution line 26 Small customer 27 Large customer CP Connection point

Claims (4)

A high-voltage distribution line extending from the secondary side of the transformer in the substation;
A first power line modem connected to a first connection point on the high voltage distribution line;
Connected to a second connection point on the high-voltage distribution line located downstream from the first connection point when viewed from the substation, and performs power line communication with the first power line modem via the high-voltage distribution line. A second power line modem to perform;
A power line communication system comprising: a signal conditioner including at least one magnetic core provided on the high-voltage distribution line and upstream of the first connection point. A switch provided on the high-voltage distribution line;
The power line communication system according to claim 1, wherein the second power line modem transmits and receives a control signal for controlling the switch. A high-voltage lead wire provided in the substation, one end of which is connected to the high-voltage distribution line, and a phase advance capacitor connected to the high-voltage lead wire;
The power signal communication system according to claim 1, wherein the signal conditioner is provided on a downstream side of a connection point of the high-voltage lead-in line.   The high-voltage distribution line includes first to third distribution lines, and the signal conditioner includes first to third magnetic cores provided on the first to third distribution lines, respectively. Item 4. The power line communication system according to any one of Items 1 to 3.