JP2004015165A - Repeater for power line carrier, optical/power line carrier apparatus for power line carrier, and power line carrier system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive communication system capable of increasing a transmission capacity. <P>SOLUTION: The communication system is provided with: optical branching devices 15a, 15b for branching optical signals transmitted through an optical fiber 14; optical/power line carrier apparatuses 16a, 16b connected to low voltage power lines 4a to 4d to supply power to a plurality of users 8a to 8d, for superimposing an electric signal obtained by converting the optical signals outputted from the optical branching devices 15a, 15b on the power sent from the low voltage power lines 4a to 4d and transmitting the result to users 8a to 8d through power line carrier; and repeaters 9b to 9d connected to power service lines 6c to 6h and amplifying a communication signal for the power line carrier. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power line carrier repeater, an optical / power line carrier device, and a power line carrier system for transmitting information between users such as individuals and companies.
[0002]
[Prior art]
In recent years, a large amount of information has been transmitted between companies and individuals via a communication network represented by the Internet. With the increase in the amount of information to be transmitted, there is a demand for an improvement in the transmission capacity (transmission speed) of a communication path. As communication means, there are optical fiber communication, wireless communication, ADSL, power line carrier, and the like. In any case, high-speed communication is required. An example of power line carrier communication using a power line as a communication path is disclosed in, for example, JP-A-2001-156873, in which a master station device (master) installed at a pole transformer and a child device installed in each home are provided. It is shown that communication is performed between station devices (slaves) using a low-voltage distribution line that is a secondary side of a pole transformer.
[0003]
[Problems to be solved by the invention]
However, the distance of the low-voltage distribution line drawn from the pole transformer to each home is several tens to several hundreds of meters, and a plurality of homes are connected to this low-voltage distribution line (also referred to as a distribution line). For this reason, high-frequency electric noise from home appliances and other appliances (eg, personal computers, printers, etc.) used in each home, particularly inverter appliances and IH (induction heating) cookers, which have become widespread in recent years, is generated by household appliances. It is superimposed on this low-voltage distribution line via the power supply line.
[0004]
In addition, the distance of the low-voltage distribution line is relatively long, from several tens of meters to several hundreds of meters, and the low-voltage distribution line has poor communication characteristics unlike communication cables. When communication is performed by power line carrier between slave stations installed in a home, a communication signal is attenuated, and the signal-to-noise (S / N) ratio of a signal received by the master station or the slave station is used. However, there is a problem that the communication speed cannot be increased as a result.
[0005]
Further, in the case of an apartment house, it is conceivable that an optical fiber is laid to the entrance of the apartment house or an ADSL station is installed. In this case, the master station device is installed at the entrance of the apartment house, and the slave station device is installed in each home, but the distance of the distribution line between the master station device and each home is several tens of meters or more. . In addition, high-frequency electric noise from home electric appliances is superimposed on distribution lines. Therefore, even in this case, when communication is performed by power line carrier between the master station device and the slave station devices installed in each home, the communication signal is attenuated, and the reception signal at the master station device and the slave station device is reduced. S / N, which is the signal-to-noise ratio, cannot be sufficiently secured, resulting in a problem that the communication speed cannot be increased. In other words, in an environment where the distance between the power lines between the master station and the slave stations is several tens of meters or more and home appliances and other devices are connected to the power lines, the signal-to-noise ratio of the signals received by the master station device and the slave station device is reduced. However, there is a problem that the S / N ratio cannot be sufficiently secured, and as a result, the communication speed cannot be increased.
[0006]
Therefore, a main object of the present invention is to provide a power line carrier repeater, an optical / power line carrier device, and a power line carrier system capable of increasing the transmission speed (transmission capacity) between a master station device and a slave station device. It is in.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a method for communicating between a power line carrier device corresponding to a master station device and a power line carrier device corresponding to a slave station device when performing communication by power line carrier in which a communication signal is superimposed on a power line. And a power line carrier repeater for amplifying the power line carrier signal during this time. Further, an optical / power line carrier connected to the transformer with an impedance equal to or higher than a predetermined value is used. Further, the power line carrier system includes the repeater and / or the optical / power line carrier device.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments of the present invention include (1) the first embodiment in which the communication system uses a power line carrier signal via a repeater that amplifies the power line carrier signal, and (2) a single-phase three-wire power line in which a low-voltage power line is used. The second embodiment, which is a communication system using a carrier signal, and (3) the third embodiment, which is a communication system using a power line carrier signal in an apartment house, will be described.
[0009]
[First Embodiment]
First Embodiment A mobile communication system will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration of a power line carrier system according to a preferred embodiment to which the communication system according to the first embodiment is applied.
[0010]
In FIG. 1, a high-voltage power line 1 is installed on utility poles 2a and 2b, and transmits high-voltage (6.6 KV in this embodiment) power. The primary sides of transformers 3a and 3b are connected to the high-voltage power line 1, and the transformers 3a and 3b convert high-voltage power transmitted through the high-voltage power line 1 to low voltages (100V and 200V in this embodiment). The voltage is transformed and output from the secondary side. As shown in the figure, a transformer 3a is installed on the utility pole 2a, and a transformer 3b is installed on the utility pole 2b. The low voltage power lines 4a and 4b are connected to the secondary side of the transformer 3a, and the low voltage power lines 4c and 4d are connected to the secondary side of the transformer 3b.
[0011]
The low-voltage power lines 4a, 4b are installed on the utility poles 5a, 5b, 5c, and transmit the low-voltage power output from the transformer 3a. On the other hand, the low-voltage power lines 4c and 4d are installed on the utility poles 5d and 5e, and transmit the low-voltage power output from the transformer 3b. In the present embodiment, two electric poles on which the high-voltage power line 1 is installed and two transformers are shown, but actually more electric poles and transformers are provided.
[0012]
The low-voltage power lines 4a and 4b are connected to power service lines 6a and 6b at the utility pole 5a, the power service lines 6c and 6d are connected to the utility pole 5b, and the power service lines 6e and 6f are connected to the utility pole 5c. The power drop lines 6a and 6b are drawn into the user's home 8a via the power meter 7a, and supply low-voltage power transmitted through the low-voltage power lines 4a and 4b to the home power line 12a in the user's home 8a. With respect to the power service lines 6c, 6d, 6e, 6f, low-voltage power is supplied to the home power lines 12b, 12c in the user homes 8b, 8c via repeaters 9b, 9c and power meters 7b, 7c, which will be described later. On the other hand, the low-voltage power lines 4c and 4d are connected to the power service lines 6g and 6h via the power poles 5d and 5e, and the power service lines 6g and 6h are drawn into the user's house 8d via the repeater 9d and the power meter 7d. The low-voltage power transmitted through the low-voltage power lines 4c and 4d is supplied to the home power line 12d in the user home 8d.
[0013]
As described above, after the high-voltage power transmitted through the high-voltage power line 1 is transformed into a low voltage, it is supplied to the user homes 8a to 8d. The wattmeters 7a to 7d provided for each of the user homes 8a to 8d measure the amount of power used in the user homes 8a to 8d. In FIG. 1, three user houses to which power is supplied via the low-voltage power lines 4a and 4b are shown, and one user house to which power is supplied via the low-voltage power lines 4c and 4d is shown. In general, about 10 user houses receive power supply via the same low-voltage power line.
[0014]
In FIG. 1, a service provider 13 is connected to the Internet 11 as an example, and an optical fiber 14 is connected. The optical fiber 14 is laid on utility poles 2 a and 2 b like the high-voltage power line 1. The optical fiber 14 serves as a communication path between the user homes 8a to 8d and the service provider 13. The optical fiber 14 is split by optical splitters 15a and 15b, and is connected to optical / power line carriers 16a and 16b provided on utility poles 2a and 2b. The optical fibers may be branched by fusing together without using the optical splitters 15a and 15b. The optical / power line carrier 16a is also connected to the low-voltage power lines 4a and 4b, and outputs information transmitted by the optical fiber 14 to the low-voltage power lines 4a and 4b, while transmitting information transmitted by the low-voltage power lines 4a and 4b. Is output to the optical fiber 14. Here, there are two types of information transmitted by the low-voltage power lines 4a and 4b: an upstream signal and a downstream signal as follows.
[0015]
First, home power lines 12a, 12b, 12c and power service lines 6a to 6f output from power line carriers 10a, 10b, 10c provided in user houses 8a, 8b, 8c and connected to power line carriers 10a, 10b, 10c. Is input to the optical / power line carrier 16a via the low-voltage power lines 4a and 4b (up signal).
[0016]
On the other hand, the user homes 8a, 8b are output from the optical / power line carrier 16a and connected to the optical / power line carrier 16a via the low-voltage power lines 4a, 4b, the power drop lines 6a to 6f, and the home power lines 12a, 12b, 12c. , 8c provided to the power line carriers 10a, 10b, 10c. The power line carriers 10a, 10b, 10c are connected to a personal computer (not shown in FIG. 1) disposed in the user's house 8a, 8b, 8c as an example, and information and light output from the personal computer are output. / A device for transmitting and receiving information output from the power line carrier device 16a by power line carrier (downlink signal).
[0017]
The power line carrier 10d is connected to the power service lines 6g and 6h, and transmits and receives information between a personal computer in the user's home 8d and the optical / power line carrier 16b, like the power line carriers 10a, 10b and 10c. Do.
[0018]
In addition, a power line carrier technology for transmitting information by superimposing information on a power line is generally well known, and thus detailed description is omitted, but a transmission method is briefly described. In general, when performing power line carrier, an analog communication system such as a frequency modulation system, a phase modulation system, a spread spectrum system, and an orthogonal frequency division multiplexing (OFDM) system is used. Of these, the spread spectrum method is a method of transmitting data by spreading it on the frequency axis, and therefore has the advantage of being resistant to interference waves, and is less likely to be affected by electric noise generated from equipment connected to the power line. However, a wide frequency band is required to spread the spectrum. Therefore, when there is a restriction on the communication bandwidth to be used, a restriction is imposed on the data communication speed. On the other hand, the OFDM system is a multi-carrier modulation system using a plurality of carriers (subcarriers), and each carrier has an orthogonal relationship. For this reason, the frequency components of each carrier may overlap each other, and much more carriers can be used as compared with a normal frequency division multiplexing system. Therefore, when the frequency utilization efficiency is high and information must be transmitted in a limited frequency band such as power line carrier, it is effective for transmitting a large amount of data at high speed.
[0019]
FIG. 10 shows the result of actually measuring the electric noise in the low-voltage power lines 4a and 4b, which is the secondary side of the transformer 3a. As shown in the figure, it is understood that the noise level at a low frequency is high below about 500 KHz. This electric noise is electric noise emitted from the user's homes 8a to 8c. Therefore, the S / N, which is the ratio between the communication signal level as the power line carrier and the noise level, decreases. When the S / N ratio decreases, a communication error easily occurs, and high-speed communication becomes difficult. However, since the noise level is low above about 500 KHz, the S / N is high and high-speed communication is possible. Therefore, high-speed data communication of several tens Mbps or more can be performed by power line carrier using a band of several MHz to several tens MHz. Therefore, at least between the optical / power line carrier devices 16a and 16b and the power line carrier devices 10a to 10d, power line carrier using a frequency band of several MHz to several tens MHz is performed. As a result, the occurrence of communication errors is reduced, and the frequency of occurrence of coding rate reduction and retransmission due to error correction is significantly reduced, so that higher-speed data communication is possible.
[0020]
Again, in FIG. 1, the repeaters 9b and 9c amplify the communication signal of the power line carrier communication transmitted by the power line carrier device or the optical / power line carrier device, but do not hinder the power supply to the user's home via the power drop line. . Although no repeater is connected to the user home 8a, this is because the communication signal of the power line carrier communication between the optical / power line carrier 16a and the power line carrier 10a in the user home 8a is not greatly attenuated and is stable. High-speed communication is possible, and amplification of a communication signal is not required. The reason is that the distance of the power line between the optical / power line carrier 16a and the power line carrier 10a in the user's home 8a is relatively short, about 10 m, and the communication signal of the power line carrier is not greatly attenuated. This is because there is no need to amplify this communication signal.
[0021]
On the other hand, the distance of the power line between the optical / power line carrier 16a and the power line carrier 10b in the user home 8b and the distance of the power line between the optical / power line carrier 16a and the power line carrier 10c in the user home 8c are Since the distance is from several tens of meters to one hundred and several tens of meters, the communication signal of power line carrier is attenuated, and stable high-speed communication cannot be realized. For this purpose, repeaters 9b and 9c are installed to amplify the communication signal of the power line carrier communication to compensate for the signal attenuation. In particular, the wiring length of the power line is not so long in the user's premises, but since the power line has a large number of branches, if several MHz to several tens of MHz are used as the communication band, the effect of the reflection of the communication signal will increase because of the high frequency. In addition, attenuation at a plurality of frequencies in the communication band increases. Therefore, the attenuation inside the user's house and the attenuation outside the user's house become almost equal near the wattmeters 7b and 7c, and when the repeaters 9b and 9c are installed there, the optical / power line carrier 16a Since the communication signal is similarly amplified from any direction for the power line carrier communication between the power line carrier devices 10b and 10c in the user homes 8b and 8c, stable high-speed communication can be realized.
The same applies to the user house 8d. By installing the repeater 9d near the wattmeter 7d, the power / line carrier communication between the optical / power line carrier 16b and the power line carrier 10d in the user house 8d can be prevented. Since the communication signal is similarly amplified from either direction, stable high-speed communication can be realized.
As described above, the repeaters 9b and 9c control the optical / power line carrier 16a and the power line carriers 10b and 10c based on the attenuation of the power line carrier signal between the optical / power line carrier 16a and the power line carriers 10b and 10c. Stable high-speed communication can be realized by installing the power line at a substantially intermediate position (corresponding to the vicinity of the watt meters 7b, 7c) of the power line to be connected.
[0022]
Even if the repeaters 9b, 9c, 9d are installed inside the house to some extent than the watt-hour meters 7b, 7c, 7d, there is no difference in the communication speed, but in that case, the power consumption of the repeaters 9b, 9c, 9d is It is added to each household's power usage, and the individual's power usage fee increases slightly. By installing the repeaters 9b, 9c, 9d closer to the power service lines 6c to 6h than the wattmeters 7b, 7c, 7d, it is possible to suppress an increase in the power consumption of individuals.
[0023]
Next, the power line carrier 10a will be described with reference to FIG.
A case where an electronic mail is sent from a personal computer in the user home 8a to the user home 8d will be described. As shown in FIG. 2, a personal computer 81 is installed in the user's home 8a, and the personal computer 81 is used to send an e-mail. Note that the personal computer 81 is supplied with power from the home power line 12a drawn into the user home 8a. When an electronic mail is sent by the personal computer 81, the mail address of the destination and its own mail address (sending mail address) are input together with the mail text.
[0024]
The mail text, the destination mail address and the source mail address (hereinafter referred to as the mail text, the destination mail address and the source mail address) input to the personal computer 81 are referred to as the protocol conversion circuit 103 of the power line carrier 10a. Is input to The personal computer 81 and the protocol conversion circuit 103 are connected by, for example, Ethernet (registered trademark).
[0025]
The protocol conversion circuit 103 converts the input mail information into a data format shown in FIG. 3A and outputs it to the power line communication circuit 102. Specifically, the address of the power line carrier 10a is assigned to the source address SA, the address of the optical / power line carrier 16a is assigned to the destination address DA, and the mail information is assigned to the transmission data DATA, and is output to the power line communication circuit 102. When there are a plurality of pieces of information to be transmitted, the protocol conversion circuit 103 determines the order of the plurality of pieces of information to be transmitted and arranges and outputs the pieces of information as shown in FIG.
[0026]
After converting the input information from digital to analog, the power line communication circuit 102 multiplexes the home power line 12a with the transmitted power via the coupling circuit 101. The power line carrier communication signal superimposed on the home power line 12a is transmitted to the optical / power line carrier device 16a via the power service lines 6a, 6b and the low voltage power lines 4a, 4b. The coupling circuit 101 includes a transformer Tr1 and a capacitor C1 so that the commercial frequency power applied to the home power line 12a is not applied to the power line communication circuit 102 and the power line carrier communication signal is passed as it is. I have to.
[0027]
Next, the optical / power line carrier 16a will be described with reference to FIG.
In the optical / power line carrier 16a shown in FIG. 4, the power line communication circuit 164 fetches information superimposed on the power transmitted through the power service lines 6a and 6b via the low voltage power lines 4a and 4b and the coupling circuit 165, and Is confirmed to be the address of the optical / power line carrier 16a. If DA is not the address of the light / power line carrier 16a, it is ignored. If DA is the address of the light / power line carrier 16a, the power line communication circuit 164 outputs the mail information to the protocol conversion circuit 163. The protocol conversion circuit 163 converts the input mail information from analog to digital and outputs it to the communication circuit 162. The communication circuit 162 adds the address of the service provider 13 to the input mail information, converts the information into a predetermined format for transmission by the optical fiber 14, and outputs the information to the optical / electrical conversion circuit 161. . The optical / electrical conversion circuit 161 converts the information of the input electric signal into an optical signal and outputs the optical signal to the optical splitter 15a. The information input to the optical splitter 15a is input to the service provider 13 whose address is specified via the optical fiber 14 and the Internet 11. The service provider 11 has a mail server (not shown), and stores the input mail information in the mail server.
[0028]
A personal computer is installed in the user's home 8d similarly to the user's home 8a, and it is possible to check the mail server of the service provider 13 for e-mail sent to the user using the personal computer. Specifically, it transmits its own mail address and mail confirmation request to the service provider 13 via the power line carrier 10d and the optical / power line carrier 16b. Since the configuration and operation of the power line carrier 10d and the optical / power line carrier 16b are the same as the operations of the power line carrier 10a and the optical / power line carrier 16a, a detailed description is omitted, but the user home 8d and the power A repeater 9d is provided between the service lines 6g and 6h, and amplifies the communication signal attenuated by the repeater 9d to perform communication. When a mail confirmation request is given from the user home 8d to the service provider 11, the service provider 11 extracts information in which the mail address assigned to the user home 8d is the destination mail address, and includes the information in the information. The mail body and the mail address of the sender are transmitted to the personal computer installed at the user's home 8d. The transmission and reception of the e-mail are performed as described above.
[0029]
In the present embodiment, it is also possible to directly exchange information between the power line carriers. For example, when information is transmitted from the personal computer at the user's home 8a to the personal computer at the user's home 8b, the information can be transmitted using only the power line carrier via the power service lines 6a to 6d and the low-voltage power lines 4a and 4b. In this case, information is transmitted from the power line carrier 10a using the destination address DA as the address of the power line carrier 10b. This is generally called N-to-N communication. By the way, when performing N-to-N communication, there is a possibility that a communication collision occurs due to asynchronous communication. In such a case, performing one-to-N communication has better communication efficiency. That is, in this case, information transmission between the power line carriers is preferably performed via the optical / power line carrier.
[0030]
Next, the positional relationship between the transformer 3a and the power lines 4a, 4b, 6a, 6b of the optical / power line carrier 16a will be described.
As a result of repeating and examining various experiments, it became clear that the transformer 3a has a capacitor component, and this capacitor component greatly attenuates the signal. The optical / power line carrier 16a is preferably connected at a position extended from the transformer 3a by at least 10 m by the power lines 4a, 4b, 6a, 6b.
The impedance of the power line can be expressed by ωL = 2πfL, where ω is an angular frequency, L is an inductance, and f is a frequency. L is ωL = 0.6Ω / m when a signal having a frequency of 0.1 μH (microhenry) and a frequency of 1 MHz flows through the power line 1m.
Therefore, the length of 10 m or more corresponds to 6 Ω (0.6 Ω / m) or more in impedance of the power lines 4 a, 4 b, 6 a, and 6 b. In other words, the provision of the signal attenuation preventing means having an impedance of 6Ω or more is equivalent to the installation of the cable at a length of 10 m or more. That is, if the signal attenuation preventing means is provided, the optical / power line carrier 16a is connected to a power line equivalent to extending the power line by 10 m or more even if the power line is not actually extended by 10 m or more from the transformer 3a. . The signal attenuating means can be constituted by a normal LCR, and the signal attenuating preventing means may be inside or outside the optical / power line carrier 16a.
On the other hand, the upper limit is not particularly limited. Even if the distance between the power lines 4a and 4b is lengthened, it is a part unrelated to communication, and the power line carrier signal is not attenuated by the lengthening. However, when the upper limit of the power line to be extended is increased, the length of the optical fiber extended from the optical branching device 15a tends to increase accordingly. The main optical fiber 14 does not pass through all the poles, and if the length of the power line extending from the transformer 15a is increased, the distance of the optical fiber that branches off from the main optical fiber 14 and extends is also increased. Tend to be. Branching and extending the optical fiber from the main optical fiber 14 is costly and time-consuming. Therefore, considering these factors, it is better that the power line extending from the transformer 3a to the optical / power line carrier 16a is shorter, and if there is no other factor, the connection should be made approximately 10 m.
[0031]
Next, the repeater 9d will be described with reference to FIG.
FIG. 5 shows the configuration of the repeater 9d as a representative. A repeater 9d is provided between the power service lines 6g and 6h and the power meter 7d of the user's house 8d. The repeater 9d is provided with a blocking filter 96. The blocking filter 96 has a high impedance with respect to the communication frequency, passes the power of the band commercial frequency as it is, and blocks high-frequency signals including the communication frequency band. Therefore, it is possible to prevent high-frequency electrical noise generated in the home power line from going out of the home from devices such as home appliances used in the home, and, as will be described later, a signal amplified and output by the repeater is input to the input of the amplifying means. It is provided in order to prevent return, further amplification, and ultimately oscillation or saturation.
[0032]
The repeater 9d has a bidirectional amplification function. The communication signal transmitted from the optical / power line carrier 16b is input to the filter 92 via the coupling circuit 91a. The filter 92 is a band-pass filter that allows only the frequency band of the communication signal from the optical / power line carrier 16b to pass and blocks the other bands. For example, as shown in FIG. 6, the communication signal from the optical / power line carrier 16b is a communication signal in the band (downlink communication band) from the frequency f3 to f4, and the communication signal in this band is output by the filter 92. Signals in other bands are suppressed. The signal output by the filter 92 is amplified by the amplifier 93 and is superimposed on the home power line 12d via the coupling circuit 91b. Since the output signal of the amplifier 93 superimposed on the home power line 12d by the blocking filter 96 is not re-input to the filter 92, the amplified signal does not finally oscillate or saturate.
[0033]
Also, as shown in FIG. 6, the filter 94 is a band-pass filter that allows communication signals in a band (uplink communication band) from frequency f1 to f2 to pass, and suppresses signals in other bands. Is not re-input to the filter 92 via the filter 94 and the amplifier 95, so that also in this case, the amplified signal does not eventually oscillate or saturate.
[0034]
On the other hand, a communication signal transmitted from the power line carrier 10d in the user's house 8d is input to the filter 94 via the coupling circuit 91b. The filter 94 is a filter that allows only the frequency band of the communication signal from the power line carrier 10d to pass and blocks the other bands. That is, communication signals in the band from frequency f1 to f2 in FIG. 6 are output by the filter 94, and signals in other bands are suppressed. The signal output by the filter 94 is amplified by the amplifier 95 and is superimposed on the power drop lines 6g and 6h via the coupling circuit 91a. Since the output signal of the amplifier 95 is not re-input to the filter 94 by the blocking filter 96 and the filter 92, the amplified signal does not eventually oscillate or saturate.
[0035]
Further, the repeater 9d includes band-pass filters of a filter 92 and a filter 94, and amplifies only communication signals in a band from frequency f1 to f2 (uplink communication band) and a band from frequency f3 to f4 (downlink communication band). Since the communication is performed and the signal is not amplified outside the band, the amplified communication signal propagates through the power line and the leaked electric field emitted from the power line is only the leaked electric field due to the amplified signal. In other words, out-of-band noise is amplified and propagates through the power line, so that no leaked electric field is generated. Instead, a leaked electric field is generated only for the signal in the communication band amplified by the repeater 9d. In this case, no leakage electric field is generated, so that there is an effect that the leakage electric field can be suppressed. By suppressing the leaked electric field, it is possible to reduce the influence on other communication such as wireless communication and broadcast reception and the radio interference affecting other things.
Furthermore, the repeater 9d can divide the amplification degree stepwise. FIG. 13 shows a part related to the amplification of the amplifiers 93 and 95 provided in the repeater 9d. The amplification degree can be expressed by amplification degree = R2 / R1, where the resistances are R1 and R2. The amplification degree can be changed by changing the value of R2. That is, a resistor is arranged in parallel with the amplifiers 93 and 95, and a switch is provided on the resistor. By operating this switch, the degree of amplification of the input and output can be changed step by step. When divided in stages, an additional configuration can be made by the dotted line in the figure, but it is actually whether R2 is on or off.
When the repeater 9d amplifies the communication signal and the signal may be saturated, the saturation can be prevented by operating the switch mechanically, and the amplification is adjusted by the switch by simply attaching the repeater 9d. The method can also be used.
[0036]
Next, the blocking filter 96 will be described with reference to FIG.
FIG. 7 shows a configuration of the blocking filter 96. As illustrated, the blocking filter 96 is configured by an LCR circuit. Note that L is a coil, C is a capacitor, and R is a resistor. ZL is a surge absorber that absorbs large electric noise such as lightning noise. In FIG. 7, the surge absorber is provided on the power service lines 6g and 6h, which are easily affected by lightning noise. May be. FIG. 7 shows the configuration of a single-phase three-wire blocking filter. The single-phase two-wire blocking filter can be configured by a portion surrounded by a dotted line in the drawing.
[0037]
By configuring the repeater 9d as described above, a communication signal by power line carrier is amplified in real time, so that communication can be performed without impairing the high-speed communication speed of power line carrier.
[0038]
Further, the optical fiber 14 and the low-voltage power lines 4a to 4d are connected via optical / power line carriers 16a and 16b, and the optical fiber 14 and the user's homes 8a to 8d are connected via repeaters 9b to 9d as necessary. Since communication is performed by transport, it is not necessary to lay an optical fiber in the user's house, and an inexpensive communication system can be constructed.
[0039]
In the present embodiment, a plurality of power line carriers are provided for one optical / power line carrier, and therefore, compared with a case where one power line carrier is provided for one optical / power line carrier. Since the number of optical / power line carriers may be small, the cost of the communication system is reduced.
[0040]
[Second embodiment]
Next, a communication system according to a second embodiment will be described with reference to the drawings.
8 differs from FIG. 1 in that the power line carrier 10a and the power line carrier 10b 'are not connected between the same lines. Hereinafter, points different from FIG. 1 will be described. A case where a repeater is unnecessary for the power line carrier 10b 'is shown, and a case where a repeater is necessary is shown in FIG.
[0041]
As shown in FIG. 8, the transformer 3a 'of this embodiment is provided with two systems of a line voltage of 100 V by connecting the low-voltage power line 4b, which is the neutral point on the secondary side, to the ground. Thus, a single-phase 200V is supplied to the user's house. The reason why the ground is provided is to prevent primary high voltage 6.6 KV electricity from flowing to the user's house when the transformer 3a 'has an accident. As shown in the figure, in this embodiment, the optical / power line carrier 16a is connected to the low voltage power lines 4a, 4b, and the power line carrier 10a is similarly connected to the low voltage power lines 4a, 4b. On the other hand, the power line carrier 10b 'is connected to the low-voltage power lines 4b and 4g.
[0042]
As described above, in this embodiment, since the power line carrier 10b 'is connected between lines different from the optical / power line carrier 16a, the bridge circuit 17 is connected between the lines as shown in FIG. Provided. In other words, the bridge circuit 17 generates the signal V1 also between the low-voltage power lines 4b and 4g when the signal V1 is output from the optical / power line carrier 16a to the 100V line between the low-voltage power lines 4a and 4b. Is a role of the bridge circuit 17, and is constituted by the transformer Tr and the capacitor C so as to induce the signal V1 between the low-voltage power lines 4b and 4g.
[0043]
The dashed line in FIG. 8 indicates the transmission path of the signal V1 output from the optical / power line carrier 16a between the low-voltage power lines 4a and 4b. As shown in the figure, the signal V1 output between the low-voltage power lines 4a and 4b from the optical / power line carrier 16a is induced between the low-voltage power lines 4b and 4g by the transformer Tr of the bridge circuit 17 and transmitted to the power line carrier 10b '. Is done.
[0044]
As described above, according to the present embodiment, by providing the bridge circuit 17 so as to be connected between the respective lines, the low-voltage power line on the secondary side is a single-phase three-wire type like the transformer 3a '. Therefore, even if the power service lines 6a, 6b and the power service lines 6c, 6d are connected between different lines, the signal output from the optical / power line carrier 16a is transmitted to both the power line carrier 10a, 10b '. Information can be reliably transmitted to each user's home.
[0045]
In FIG. 9, the bridge circuit 17 is connected between the low-voltage power lines 4a, 4b, and 4g as described above (not shown), and the light / power line is connected between the low-voltage power lines 4a and 4b and between the low-voltage power lines 4b and 4g. The communication signal from the transport device 16a is induced. However, a blocking filter 96 'is provided in the repeater 9b', and the blocking filter 96 'directly transmits communication signals induced between the low-voltage power lines 4a and 4b and between the low-voltage power lines 4b and 4g, respectively. , 4b 'and between the low-voltage power lines 4b', 4g '. In this case, the communication signals between low-voltage power lines 4b and 4g are output between low-voltage power lines 4b 'and 4g' by coupling circuits 91a and 91b, and the communication signals between low-voltage power lines 4b 'and 4g' are output from low-voltage power lines 4b and 4g '. It will be output between 4g.
[0046]
Here, by providing the same bridge circuit 97 as bridge circuit 17 in FIG. 8, a communication signal between low-voltage power lines 4b 'and 4g' is induced between low-voltage power lines 4a 'and 4b'. Therefore, even if the power line carrier is connected between the low voltage power lines 4a 'and 4b' or between the low voltage power lines 4b 'and 4g' in the house, communication with the optical / power line carrier becomes possible. The configuration of the blocking filter for a single-phase three-wire system is the entire circuit configuration shown in FIG. As described above, even when a single-phase three-wire low-voltage power line is used and a repeater is required, communication between the optical / power line carrier and the home power line carrier can be performed by providing the repeater with a bridge circuit.
Note that the bridge circuit 97 may be included in the repeater 9b 'or may be provided externally.
[0047]
9 shows that the communication circuit between the low-voltage power lines 4b 'and 4g' is induced between the low-voltage power lines 4a 'and 4b' by providing the bridge circuit 97, but FIG. By providing the coupling circuit 91b ', communication signals can flow between 4a' and 4b 'and between 4b' and 4g '.
Therefore, even if the power line carrier is connected between the low voltage power lines 4a 'and 4b' or between the low voltage power lines 4b 'and 4g' in the house, communication with the optical / power line carrier becomes possible.
[0048]
[Third embodiment]
Next, the case of an apartment house according to the third embodiment will be described with reference to the drawings.
FIG. 12 shows a positional relationship between the transformer 3a and the optical / power line carrier 16a in the apartment house 20 in terms of the length of the power line. As described above, it has been found that the transformer 3a has a capacitor component, and this capacitor component greatly attenuates the signal. The optical / power line carrier 16a is preferably connected at a position extended by at least 10 m from the transformer 3a by the power line 4a. For this reason, the optical fiber 14 is pulled to the entrance of the apartment house 20, and the optical / power line carrier is provided. 16a is installed near the distribution board of the apartment house 20. Electric power is supplied between the distribution board and each household in the apartment house by the power line 4a '.
Further, in each home in the apartment house, the power line carrier signal is attenuated by 4 dB at 10 m due to the distance between the optical / power line carrier device 16a and the power line carrier device in each home in the apartment house. When the distance is 50 m from the optical / power line carrier 16a, the attenuation is 20 dB, and the repeater 9b is required. Therefore, in the apartment house 20, each home remote from the optical / power line carrier device 16a is provided with the repeater 9b, and communication is performed by the power line carrier signal via the repeater 9b.
As in the case of FTTH, in the case of an apartment house 20 compared to installing the optical / power line carrier 16a near each home (comparing to drawing optical fiber to individual homes) It can be said that the labor and cost required for branching the optical fiber and bringing the optical fiber to the vicinity of the distribution board of the apartment house are small.
[0049]
The present invention described above can be widely modified without being limited to the above embodiment.
[0050]
【The invention's effect】
In a power line carrier communication system, it is possible to increase the signal-to-noise ratio and increase the transmission speed (transmission capacity) with an inexpensive configuration.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a communication system according to a preferred embodiment of the present invention.
FIG. 2 is a configuration diagram of a power line carrier 10a.
FIG. 3 is a diagram showing a data format of information transmitted by power line carrier.
FIG. 4 is a configuration diagram of an optical / power line carrier device 16a.
FIG. 5 is a configuration diagram of a repeater.
FIG. 6 is an explanatory diagram of a communication band.
FIG. 7 is a circuit diagram of a blocking filter in a repeater.
FIG. 8 shows a low-voltage power line and a bridge circuit of a communication system according to another embodiment of the present invention.
FIG. 6 is a diagram showing a connection relationship with the STA.
FIG. 9 shows the relationship between a low-voltage power line and a bridge circuit of a communication system when there is a repeater
It is a figure showing a connection relation.
FIG. 10 is a diagram showing the power supply on the low-voltage power lines 4a and 4b which are the secondary side of the transformer 3a in FIG.
It is a figure showing the result of having measured qi noise.
FIG. 11 is a diagram showing a connection relationship between a low-voltage power line and a coupling circuit in a single-phase three-wire communication system.
FIG.
FIG. 12 is a connection diagram of an optical / power line carrier and a repeater in an apartment house.
FIG. 13 is a configuration diagram of a switch that divides amplification of a repeater in stages.
[Brief description of reference numerals]
1 High voltage power line, 2a, 2b, 5a to 5e Power pole, 3a, 3b Transformer, 4a to 4d Low voltage power line, 6a to 6h Power incoming line, 7a to 7d Power meter, 8a to 8d User home, 9b to 9d: repeater, 10a to 10d: power line carrier, 12a to 12d: home power line, 13: service provider, 14: optical fiber, 15a, 15b: optical splitter, 16a, 16b: optical / power line carrier. 20: Apartment house, 91a, 91b: Coupling circuit, 92, 94: Filter, 93, 95: Amplifier, 96: Blocking filter, 97: Bridge circuit

Claims (11)

A repeater used in power line carrier communication for communicating by a power line carrier signal in which a communication signal is superimposed on a power line,
An optical / power line carrier device for mutually converting the optical signal as the communication signal and the power line carrier signal, and a power line carrier transmitted and received between the power line carrier device for mutually converting the power line carrier signal and the communication signal A power line carrier repeater, comprising: amplification means for amplifying a signal. The repeater is installed at a substantially intermediate position of a power line connecting the optical / power line carrier and the power line carrier with reference to the attenuation of the power line carrier signal between the optical / power line carrier and the power line carrier. That
The power line carrier repeater according to claim 1, wherein: The repeater is arranged in the vicinity of a watt hour meter at the user home where the power line carrier is installed,
The power line carrier repeater according to claim 1, wherein: The repeater includes a blocking filter that blocks a power line carrier signal superimposed on the power,
The amplification means is provided in parallel with the blocking filter,
The power line carrier repeater according to any one of claims 1 to 3, characterized in that: Amplifying means of the repeater has a switch function, and the degree of amplification can be divided into at least two stages of ON and OFF by opening and closing the switch function;
The power line carrier repeater according to any one of claims 1 to 4, characterized in that: When the power line is a single-phase three-wire system, a bridge circuit that generates a signal on the other two single-phase three-wire lines when a signal is output between two of the single-phase three-wire lines of the power line. Having prepared,
The power line carrier repeater according to any one of claims 1 to 5, characterized in that: When the power line is a single-phase three-wire system, when a signal is output between two of the single-phase three-wire lines of the power line, the signal is generated in the other two single-phase three-wire lines by a coupling circuit. The power line carrier repeater according to any one of claims 1 to 5, characterized in that: An optical / power line carrier device used for power line carrier communication for communicating by a power line carrier signal in which a communication signal is superimposed on a power line and mutually converting an optical signal as the communication signal and the power line carrier signal,
While an optical fiber through which an optical signal as a communication signal is transmitted is branched from the optical branching device and connected,
A power line that is stepped down by the transformer and heads toward the user's house, having a signal attenuation prevention means having an impedance of a predetermined value or more, and having a configuration connected at a downstream position of the signal attenuation prevention means;
An optical / power line carrier device for power line carrier, characterized in that: An optical / power line carrier device that is used for power line carrier communication for communicating by a power line carrier signal in which a communication signal is superimposed on a power line, and that mutually converts an optical signal as the communication signal and the power line carrier signal,
While an optical fiber through which an optical signal as a communication signal is transmitted is branched from the optical branching device and connected,
Having a configuration connected to a power line that is stepped down by a transformer and heads toward a user's house at a position extended from the transformer by 10 m or more;
An optical / power line carrier device for power line carrier, characterized in that: The optical / power line carrier device is installed near a distribution board of an apartment house;
The optical / power line carrier device for power line carrier according to claim 8 or 9, wherein: A power line carrier system for communicating by a power line carrier signal in which a communication signal is superimposed on a power line,
A repeater according to any one of claims 1 to 7, and / or an optical / power line carrier according to any one of claims 8 to 10.
Power line carrier system characterized by the above-mentioned.

Images