JP6164989B2 - Power line communication system and power line communication method - Google Patents

Description

  The present invention relates to a power line communication system and a power line communication method for a plurality of consumers who receive power supply from a common transformer.

  In recent years, interest in the amount of electric power used in ordinary households has increased, and attention has been focused on an energy management system (HEMS: Home Energy Management System) that performs energy management in the household. In this system, the energy management device installed in the home can monitor the power consumption of the electrical devices in the home and perform control such as power saving as necessary.

  Moreover, introduction of what is called a smart meter (registered trademark) having a communication function capable of automatic meter reading is progressing as a watt-hour meter of each house. Such a watt-hour meter can provide meter reading data not only to a power supply source such as a power company but also to energy management equipment in the house. As a result, the energy management device can monitor power consumption and perform control such as power saving as necessary as described above.

  For mutual communication between the energy management device and the watt hour meter, for example, power line communication (PLC) that does not require a dedicated communication line is suitable. Particularly in apartment houses such as apartments, electricity meters are provided in meter boxes surrounded by thick concrete walls and metal doors. On the other hand, the energy management device is provided in the house. In such a situation, wireless communication is often difficult, and power line communication is also preferable in this respect.

  Communication between the watt-hour meter and the energy management device can basically be performed freely. For example, the meter reading data is randomly obtained from the energy management device and the watt-hour meter responds to this. In some cases, the energy meter randomly sends meter reading data to the energy management device.

  On the other hand, since power line communication uses a power line, there is a case where communication of one house leaks (sounds) to another house via the main distribution line in the apartment house. In such a state, if communication is performed randomly at each door, there may be cases where signals collide. Therefore, for example, a CSMA (Carrier Sense Multiple Access) system can be adopted for communication. According to the CSMA method, free communication can be performed while avoiding signal collision (see, for example, Patent Document 1).

JP 2005-73240 A

  However, when the CSMA method is adopted for power line communication in an apartment house, communication is performed in many homes. Therefore, when communication is attempted in one house, communication may already be performed in another house. Become more. In this case, communication is tried again after a random delay time (back-off time). This random delay time is to avoid conflicting again when there are multiple houses waiting to communicate. However, if the total number of apartments increases, it may be forced to try again after the back-off time.

  FIG. 10 is a diagram illustrating an example of data transmission by the CSMA method. For example, when any one of a plurality (n) of energy meters SM1 to SMn intends to transmit a signal to an energy management device, transmission is executed when a carrier of a transmission signal by another energy meter is not detected. To do. For example, when the watt-hour meter SM1 is attempting to transmit while the watt-hour meter SM1 is transmitting, retry is made after the back-off time by carrier detection. When another transmission is performed after the back-off time, the transmission cannot be performed again, and another retry must be made after the second back-off time. As the total number of apartments increases, the number of such two or more trials increases, and when the waiting time increases, the overall communication efficiency decreases.

  In view of such a conventional problem, the present invention provides a power line communication system and a power line communication method for a plurality of consumers who receive power supply from a common transformer. The purpose is to improve the efficiency of communication between the two and to enable reliable communication to be executed.

  (1) The present invention is a power line communication system for a plurality of consumers who receive power supply from a common transformer, and is provided in each of the plurality of consumers and has a power line communication function. A data aggregating device having a function of communicating with the watt-hour meter by a power line communication of a first route using a power line connecting the transformer and the watt-hour meter, and each of the plurality of consumers Provided with an energy management device having a function of communicating with the watt-hour meter by power line communication of a second route using a power line connected to the watt-hour meter, the watt-hour meter from the data aggregation device Communication with the energy management device is executed with the timing of receiving sequential polling as a timing reference.

  The first route is generally referred to as the A route, and the second route is generally referred to as the B route. In the power line communication system as described above, the watt-hour meter uses the timing of receiving polling (for example, polling for metering of electric energy) as the timing reference, and the B-route communication is performed with the energy management device. Run between. Here, polling is performed periodically. Therefore, the B route communication is periodically executed. As a result, it is possible to improve communication efficiency and realize reliable communication of the B route, particularly in the case of the B route, as compared with the case where the CSMA method is used.

(2) In the power line communication system of (1) above, communication between the watt hour meter and the energy management device may be executed following the order and timing of polling for metering of the electric energy.
In this case, if polling goes around, communication between the watt-hour meter and the energy management device is executed for all customers.

(3) In the power line communication system of (1) or (2) above, the watt hour meter may execute communication with the energy management device of the same consumer after completing the response to the polling addressed to itself. Good.
In this case, since the response from the watt hour meter to the data aggregation device for polling addressed to itself and the communication between the watt hour meter and the energy management device at the same consumer are not performed simultaneously in time, the A route, In the B route, the same frequency band can be used.

(4) In the power line communication system of (1) or (2), the watt-hour meter performs a response to polling addressed to itself using the first frequency band, and at the same time, what is the first frequency band? You may make it perform communication with the said energy management apparatus of the same consumer using a different 2nd frequency band.
In this case, interference between signals does not occur even if communication is performed simultaneously because of different frequency bands. Therefore, the limited time between polling can be utilized more effectively.

(5) Moreover, in the power line communication system according to any one of the above (1) to (4), the watt-hour meter completes a response to polling addressed to itself and communicates with the energy management device of the same consumer After completing the above, communication between a plurality of sets of watt hour meters and the energy management device may be executed in a time-sharing manner during the idle time until the next polling.
In this case, the B route can be further communicated by using the idle time between polling.

(6) In the power line communication system of (5) above, communication between a plurality of sets of watt hour meters and energy management devices in idle time is executed in a time-sharing manner in an order based on the polling order of the first route. You may be made to do.
In this case, since the order becomes clear, it is possible to more reliably perform the B route communication using the free time.

(7) In the power line communication system of (1), communication is simultaneously performed between a plurality of sets of watt hour meters and energy management devices for one polling, and the frequency bands are different in each set. May be.
In this case, interference between signals does not occur even if communication is performed simultaneously because of different frequency bands. Therefore, communication of a large number of B routes can be performed in a limited time between polling.

(8) In the power line communication system according to any one of (1) to (4) and (7), the watt-hour meter completes a response to polling addressed to itself and After the communication is completed, communication between a plurality of sets of watt hour meters and corresponding energy management devices is executed in a time-sharing manner in the idle time until the next polling, and the plurality of sets that are simultaneously executed are different from each other. You may make it use a frequency band.
In this case, the B route can be further communicated by using the idle time between polling. Moreover, even if it communicates simultaneously about several sets because it is a different frequency band, interference between signals does not arise. Therefore, communication of a large number of B routes can be performed in a limited time between polling.

  (9) On the other hand, this invention is provided in each of the some consumers who receive electric power supply from a common transformer, and connects the watt-hour meter which has a function of power line communication, and the said transformer and the said watt-hour meter. By using the power line communication of the first route using the power line, the data aggregation device having a function of communicating with the watt hour meter and the first using the power line connected to the watt hour meter provided in each of the plurality of consumers A power line communication method in a power line communication system including an energy management device having a function of performing communication with the watt hour meter by two-route power line communication, wherein: (a) the watt hour meter is sequentially transmitted from the data aggregation device. (B) The watt-hour meter performs communication with the energy management device using the timing at which the polling is received as a timing reference. A.

  The first route is generally referred to as the A route, and the second route is generally referred to as the B route. In the power line communication system as described above, the watt-hour meter uses the timing of receiving polling (for example, polling for metering of electric energy) as the timing reference, and the B-route communication is performed with the energy management device. Run between. Here, polling is performed periodically. Therefore, the B route communication is periodically executed. As a result, it is possible to improve communication efficiency and realize reliable communication of the B route, particularly in the case of the B route, as compared with the case where the CSMA method is used.

  ADVANTAGE OF THE INVENTION According to this invention, efficiency can be improved about communication between a consumer's electricity meter and energy management apparatus, and reliable communication can be performed.

1 is a schematic configuration diagram of a power line communication system according to an embodiment of the present invention for a plurality of consumers who receive power supply from a common transformer. FIG. 2 is a connection diagram focusing on power line communication of A route and B route in FIG. 1. It is a figure which shows an example of the order of the data transmission in 1st Embodiment. The horizontal direction in the figure represents the passage of time, the upper part of the horizontal line represents the A route signal, and the lower part represents the B route signal. FIG. 2 is a connection diagram focusing on power line communication of A route and B route in FIG. 1. It is a figure which shows an example of distribution of the frequency band allocated to A route and B route. It is a figure which shows an example of the order of the data transmission in 2nd Embodiment. It is a figure which shows an example when there is idle time when the same data transmission as 1st Embodiment is performed. It is a figure which shows an example of the order of the data transmission in 3rd Embodiment. It is a figure which shows an example of the data transmission at the time of using both TDMA / FDMA in idle time. It is a figure which shows an example of the data transmission by a CMSA system.

<Overall configuration>
FIG. 1 is a schematic configuration diagram of a power line communication system according to an embodiment of the present invention for a plurality of consumers who receive power supply from a common transformer. In the figure, the power line communication signals from the watt-hour meter 5 and the energy management device 7 are attenuated in the electric circuit (L2, L3, L4) and reach the transformer 3, and further the secondary side of the transformer 3 that handles the commercial frequency. / Because the attenuation between the primary sides is large, even if different transformers are connected via the common electric circuit L1 (6.6 kV), the signal is transmitted to the electric circuit L2 (100/200 V) under the different transformers. Is difficult to pass. Accordingly, a power line communication network can be locally configured for a plurality of consumers under the common transformer.

  In FIG. 1, the plurality of consumers is an apartment house 1 such as an apartment. In the housing complex 1, for example, 6.6 kV is received on the electric circuit L <b> 1 in the electric room 2 provided on the premises, and the transformer 3 transforms the single-phase three-wire 100/200 V. The output voltage of the transformer 3 is provided to each house by the electric circuit L2. In each house, the distribution board 6 is connected from the electric circuit L2 through the watt-hour meter 5 and the electric circuit L3.

On the secondary side of the transformer 3, a data aggregation device (hereinafter referred to as a concentrator) 4 is provided, and power line communication signals can be injected / extracted to / from the electric circuit L2. The concentrator 4 is connected to a power supply source via, for example, an optical fiber F, and is a device that is controlled and managed by the power supply source.
In each house, an energy management device (indicated as HEMS) 7 is connected to a distribution board 6 via an electric circuit L4. In addition, although indoor wiring is connected to the distribution board 6 and many household appliances etc. are connected, illustration is abbreviate | omitted here.

  The watt-hour meter 5 has a function of power line communication, and can communicate with the concentrator 4 by power line communication. A first route of power line communication performed by the concentrator 4 and the watt-hour meter 5 through the electric circuit L2 is referred to as an A route, for example. The energy management device 7 has a function of power line communication, and can communicate with the watt hour meter 5 by power line communication. The second route of power line communication performed by the energy management device 7 and the watt-hour meter 5 via the electric paths L3 and L4 is referred to as, for example, the B route in distinction from the A route. The A-route power line communication and the B-route power line communication are logically isolated from each other. However, the energy management device 7 of the B route can listen (listen) to the power line communication of the A route.

<< First Embodiment >>
The power line communication system (including the method, the same applies hereinafter) according to the first embodiment uses TDMA (Time Division Multiple Access).
FIG. 2 is a connection diagram focusing on power line communication of the A route and the B route in FIG. In the figure, n houses constituting the apartment house 1 are designated as rooms (houses) 1-1, 1-2,. The concentrator 4 polls the watt-hour meter 5 (or SM1 to SMn) in the frequency band f in order of, for example, SM1 to SMn, for example, in the order of SM1 to SMn. The period of meter reading (polling) for the same watt-hour meter 5 is, for example, once every 30 minutes.

  As a response to polling, the watt-hour meter 5 returns meter reading data to the concentrator 4. The concentrator 4 receives and aggregates the meter reading data and provides information to the power supply source. In this way, polling can be performed for all connected watt-hour meters 5 within a predetermined time, and responses to the polling can be obtained. Therefore, the concentrator 4 always knows the number of connected watt-hour meters 5. For example, when a reply does not come after waiting for a certain time, it may be called again or polled for the next watt-hour meter 5.

  On the other hand, the watt-hour meter 5 that has received the poll uses this as a trigger, and then transmits meter reading data to the energy management device 7 via the B route. At this time, the same frequency band f as the A route can be used.

FIG. 3 is a diagram illustrating an example of an order of data transmission in the first embodiment. The horizontal direction in the figure represents the passage of time, the horizontal line represents the A route signal, and the lower line represents the B route signal (the same applies hereinafter). As described above, if polling for meter reading of electric energy is performed in the order of SM1 to SMn, first, polling of meter reading data request (SMA1 request) arrives from the concentrator 4 to the electric energy meter SM1 via the A route. . In response, the watt-hour meter SM1 provides meter reading data (SMA1 response) to the concentrator 4 as a response to the A route. Subsequently, the watt-hour meter SM1 transmits meter reading data and the like to the energy management device 7 through the B route (SMB1 transmission). Since the SMA1 request, the SMA1 response, and the SMB1 transmission are not simultaneous in time, as described above, the same frequency band f can be used.
In addition, each transmission of SMB1 to SMBn in FIG. 3 means both bidirectional communication (request and response) between the watt-hour meter 5 and the energy management device 7, or transmission of data from the watt-hour meter 5. (The same shall apply hereinafter.)

  In the same manner, for each polling, the B route, that is, the watt hour meter 5 (SM1 to SMn) and the energy management device 7 with the polling of the A route in the order of the watt hour meters SM2, SM3,. Meter reading data is transmitted to and from. When the communication of the A route / B route for the energy meters SM1 to SMn is completed, the communication of the A route / B route is performed again in order from the energy meter SM1.

  As described above, the watt-hour meter 5 performs the B route communication with the energy management device 7 with the timing of receiving the polling for the meter reading of the electric energy as the A route communication as a timing reference. Here, polling for meter reading is performed periodically. Therefore, the B route communication is periodically executed. As a result, it is possible to improve communication efficiency and realize reliable communication of the B route, particularly in the case of the B route, as compared with the case where the CSMA method is used.

In addition, since communication between the watt hour meter 5 and the energy management device 7 is executed following the order and timing of polling, communication between the watt hour meter 5 and the energy management device 7 can be performed once the polling is completed. It is executed for all customers.
More specifically, the watt-hour meter 5 executes communication with the energy management device 7 of the same consumer after completing the response to the polling addressed to itself (FIG. 3). To the concentrator 4 and communication between the watt-hour meter 5 and the energy management device 7 at the same consumer are not performed simultaneously in time. Thus, the same frequency band (f) can be used for the A route and the B route.

  As described above, the energy management device 7 can hear (detect) that the corresponding watt-hour meter 5 has received the polling. It is also possible to request meter reading data.

  In the case of performing DR (demand response) or the like, for example, the same applies to a case where a DR signal from a host (power supply source) is transmitted to the B route via the watt-hour meter 5. In this case, as soon as the DR signal from the A route is received, the watt-hour meter 5 may transfer it to the B route. Conversely, the response signal from the energy management device 7 may be stored in the watt-hour meter 5 once after the response from the energy management device 7 is returned to the concentrator 4 at the next polling timing (DR The response is not required to be so quick except for the initial DR response.) Usually, these signals are exchanged sequentially for requests and responses to n watt-hour meters, so that n communications should be completed within a minimum of 30 minutes. When the message does not reach directly from the concentrator 4 to the watt hour meter 5 in the A route (when hop transmission is performed), the middle watt hour meter relays the signal. As soon as the meter receives the signal, the B route may be communicated.

<< Second Embodiment >>
The power line communication system according to the second embodiment uses FDMA (Frequency Division Multiple Access) in addition to TDMA.
FIG. 4 is a connection diagram focusing on the power line communication of the A route and the B route in FIG. The difference from FIG. 2 is in how to use the frequency band. The frequency band fA is used for A route communication. Frequency bands fB1, fB2,..., FBn are used for B route communication. For example, OFDM (Orthogonal Frequency Division Multiplexing) can be employed as a modulation method for power line communication. As the use band, for example, 10 to 450 kHz can be used.

  FIG. 5 is a diagram illustrating an example of the distribution of OFDM carrier frequency bands assigned to the A route and the B route. The frequency on the horizontal axis is higher toward the right. In this case, first, the frequency band is different between the A route and the B route. Moreover, as the frequency band of the B route, for example, the same frequency band can be assigned to all. Further, the same carrier frequency band may be assigned to each small group, and different carrier frequency bands may be assigned to different groups. When the total number of houses is small, it is possible to assign different carrier frequency bands for each house.

FIG. 6 is a diagram illustrating an example of the order of data transmission in the second embodiment.
As described above, if polling for meter reading of electric energy is performed in the order of SM1 to SMn, first, polling of meter reading data request (SMA1 request) arrives from the concentrator 4 to the electric energy meter SM1 via the A route. . In response, the watt-hour meter SM1 provides meter reading data (SMA1 response) to the concentrator 4 as a response to the A route. At the same time, the watt-hour meter SM1 transmits meter reading data to the energy management device 7 through the B route (SMB1 transmission). Transmission is possible simultaneously because the A route and the B route have different frequency bands.

  Similarly, for each polling, the B route, that is, the watt hour meter 5 (SM2, SM3,..., SMn, with the polling of the A route as a timing reference in the order of the watt hour meters SM2, SM3,. ) To transmit the meter reading data to the energy management device 7. When the A route / B route communication for the watt hour meters SM1 to SMn is completed, the A route / B route communication is performed again in order from the watt hour meter SM1.

  According to the second embodiment, in addition to the same effects as the first embodiment, the A route and the B route have different frequency bands, so that interference between signals does not occur even if they are simultaneously communicated. Therefore, the limited time between polling can be utilized more effectively.

<< Third Embodiment >>
FIG. 7 is a diagram illustrating an example when there is a free time when data transmission similar to that of the first embodiment is performed. In the figure, meter reading data from the electricity meter 5 in the A route is normally collected every 30 minutes, so depending on the total number of houses, meter reading data is transmitted via the B route from the electricity meter SM1 (SMB1 transmission). After that, there is a corresponding free time before the next polling, and the free time can be used as a TDMA area to perform B route signal transmission. That is, it is possible to perform communication by sequentially assigning B route communication to the TDMA area. In signal transmission, time slots may be equally divided into n slots, and B-route communication in the next order may be performed as soon as one signal transmission is completed.

  FIG. 8 is a diagram showing an example of the order of data transmission in the third embodiment according to the above procedure. In the figure, in the TDMA area of the idle time, for example, B slot communication can be assigned as B1, B2,. In this case, the B route can be further communicated by using the idle time between polling.

  In order to perform the communication of the B route more reliably using the free time, it is necessary to clearly identify the order in which data is transmitted. It is conceivable to determine the order of time slots for transmitting data in the idle time from the polling order by the A route and transmit the data. Alternatively, when transmitting the own station, the transmission may be performed as soon as the signal transmission of the other station in the previous order ends. In addition, when transmission of the other station immediately before is not performed, transmission may be performed after waiting for a certain time. When the polling cycle by the next A route is reached or when polling is detected, signal transmission may be resumed using the next idle time.

As means for more reliably recognizing that another station (other house) is communicating, for example, the following means can be considered.
The devices on the B-route side (the watt-hour meter 5 and the energy management device 7) listen to the communication of other stations, schedule the transmission order of the devices on the B-route side of the own station from the polling order of the A route. If the transmission status of the local station is predicted in advance while performing signal transmission while monitoring the transmission status of other stations, transmission timing control becomes easy. Furthermore, in PLC transmission, the watt-hour meter 5 has a higher accuracy in grasping the signal transmission status of the A route and the other B route signal transmission status than the energy management device 7. When the energy management device 7 transmits a signal to the watt hour meter 5 via the B route, the watt hour meter 5 grasps the transmission status of the other station, flags the transmission status of the other station, and notifies the energy management device 7 of the flag. It is considered that the transmission timing can be taught and signal transmission can be performed without waste. By providing the above recognition means, it is possible to control the signal transmission timing more reliably.

  Further, the frequency band of the OFDM signal band may be divided and the frequency used by each B route may be designated from the concentrator 4. At this time, the bandwidth used by each B route may be different in the communication environment depending on the environment of the power line in the house. A good frequency band can be assigned by negotiating with the concentrator 4 and the watt-hour meter 5, and the order of transmission can be determined in advance. If different frequency bands are efficiently allocated, a plurality of B routes can communicate at the same time, so that transmission can be performed efficiently.

  FIG. 9 shows a case where both TDMA / FDMA are used (for example, when three types of frequency bands are used). In this case, the free time is used as a TDMA / FDMA area. B slot timeslots using the frequency band f1 are B1, B4,..., Bn-2. Time slots using the frequency band f2 are B2, B5,..., Bn-1. Time slots using the frequency band f3 are B3, B6,..., Bn. The three types of B route communication (for example, B1, B2, and B3) performed at the same time do not cause interference between signals even if they are simultaneously communicated because they are in different frequency bands. Therefore, communication of a large number of B routes can be performed in a limited time between polling.

<Others>
In addition, although the whole structure of FIG. 1 assumes an apartment house, application of this invention is not limited to this for the power line communication system of each embodiment. For example, the present invention can be similarly applied to a plurality of detached houses under the umbrella of a common distribution transformer (for example, a pole transformer).

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1-1, 1-2, 1-n rooms (customers)
2 Electrical room 3 Transformer 4 Concentrator (data aggregation equipment)
5 Electricity meter 6 Distribution board 7 Energy management equipment (HEMS)

Claims (9)

A power line communication system for a plurality of consumers who receive power supply from a common transformer,
A watt-hour meter provided in each of the plurality of consumers and having a function of power line communication;
A data aggregation device having a function of communicating with the watt-hour meter by power line communication of a first route using a power line connecting the transformer and the watt-hour meter;
An energy management device provided in each of the plurality of consumers and having a function of communicating with the watt-hour meter by power line communication of a second route using a power line connected to the watt-hour meter,
Each time the watt-hour meter receives the polling at a predetermined timing between the time when the polling is received and the time when the next polling is received, with the timing of receiving the sequential polling from the data aggregation device as a timing reference. A power line communication system for executing communication with the energy management device.   The power line communication system according to claim 1, wherein communication between the watt-hour meter and the energy management device is executed following the order and timing of the polling for metering the amount of power.   3. The power line communication system according to claim 1, wherein the watt-hour meter executes communication with the energy management device of the same consumer after completion of a response to polling addressed to itself. The electricity meter can have rows using a first frequency band the response to the polling addressed to, simultaneously with the response to the polling of the self-addressed, using a second frequency band different from the first frequency band The power line communication system according to claim 1, wherein communication with the energy management device of the same consumer is executed.   After the watt-hour meter completes the response to the polling addressed to itself and completes communication with the energy management device of the same consumer, a plurality of sets of the watt-hour meters are set in the idle time until the next polling. The power line communication system according to any one of claims 1 to 4, wherein communication with the energy management device is performed in a time division manner.   6. The power line communication system according to claim 5, wherein communication between the plurality of sets of watt hour meters and the energy management device in the idle time is performed in a time-sharing manner in an order based on a polling order of the first route. .   The power line communication system according to claim 1, wherein communication is simultaneously performed between a plurality of sets of the watt hour meter and the energy management device with respect to one polling, and a frequency band is different in each set.   The watt hour meter completes a response to the poll addressed to itself, and after completing communication with the corresponding energy management device, a plurality of sets of the watt hour meters in an idle time until the next polling, and 8. The power line communication according to claim 1, wherein communication with the corresponding energy management device is performed in a time-sharing manner, and a plurality of sets that are simultaneously executed use different frequency bands. system. A power line of a first route that is provided in each of a plurality of consumers that receive power supply from a common transformer and has a power line communication function, and a power line that connects the transformer and the power meter The data aggregation device having a function of communicating with the watt-hour meter by communication and the power line communication of the second route provided in each of the plurality of consumers and using a power line connected to the watt-hour meter. A power line communication method in a power line communication system comprising an energy management device having a function of communicating with a meter,
The watt-hour meter receives sequential polling from the data aggregation device,
The watt-hour meter receives the polling at a predetermined timing from when the polling is received until the next polling is received with the timing when the polling is received as a timing reference. Perform communication with the device,
Power line communication method.

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