JP5814132B2 - Automatic meter reading system - Google Patents

Description

  According to the present invention, a watt-hour meter installed at each consumer has a wireless communication function to be a wireless communication terminal, and the wireless communication terminal forms a network, and meter reading data is set at predetermined time intervals (periodic meter reading). The present invention relates to an automatic meter reading system that transmits and collects data to an aggregation device by hop wireless communication.

  Currently, in the multi-hop wireless network system, as the number of wireless communication terminals participating in the network increases, there is a problem that wireless resource usage areas in the network overlap and communication collisions frequently occur.

  For this reason, for example, in the technique of Patent Document 1, the occurrence of a collision is suppressed by prescribing transmission timing specific to each wireless communication terminal in advance.

JP 2008-228176 A

  Since the communication collision avoidance technique described above is uniquely defined in advance, the maximum number of hops is defined in advance, and therefore exists within a certain range of distance from the wireless communication terminal capable of multi-hop data communication with the aggregation device. Must-have. Since the installation distribution of watt-hour meters installed at each consumer differs between urban areas and county areas, there is a large variation in the number of data collected by each aggregation device.

  Moreover, in patent document 1, it does not consider installing the watt hour meter newly in a system. In view of this, it is desirable to be able to connect to a wireless network at the discretion of the watt-hour meter and to contribute to the improvement of the variation in the number of data.

  In order to solve the above-described problems, the present invention can easily perform additional installation, and furthermore, can uniform the number of data collected by each aggregation device, and can minimize the number of aggregation devices installed. The present invention relates to an automatic meter reading system.

  To solve the above problems, the present invention provides an automatic meter reading system in which a plurality of instruments having a wireless communication function and an aggregation device are formed in a tree shape and connected by a multi-hop wireless network. Transmits the upper limit of the number of hops of the multi-hop wireless network, the number of hops to which the self belongs, the upper limit of the number of instruments, and the number of connected devices in its own communication data.

  The meter also checks the upper limit of the number of hops of the multi-hop wireless network included in the communication data transmitted by other instruments, the number of hops to which it belongs, the upper limit of the number of instruments and the number of connected devices, Determine the instrument or aggregation device.

  Further, in determining the partner instrument or aggregation device with which it communicates, the partner that does not exceed the upper limit of the number of hops and the upper limit of the number of connected devices is selected.

  In addition, for communication between the meter and the aggregation device, a time slot is set for performing communication between them in a predetermined time zone.

  In addition, the time slot is provided with the same number of communication frames as the upper limit of the number of hops when a communication frame required for bidirectional communication is one set.

  In order to solve the above problems, the present invention forms a tree between a plurality of instruments having a wireless communication function and a plurality of aggregation devices, and is connected by a multi-hop wireless network in which each aggregation device has a different radio frequency. In the automatic meter reading system, the instrument and the aggregation device transmit the upper limit of the number of hops of the multi-hop wireless network, the number of hops to which the instrument belongs, the upper limit of the number of instruments and the number of connected devices in its own communication data.

  In addition, the meter switches the frequency used by itself and confirms the communication contents of other meters or aggregation devices, and the upper limit of the number of hops of the multi-hop wireless network included in the communication data transmitted by the other meter and the self Using the number of hops to which the device belongs, the upper limit of the number of instruments and the number of connected instruments, the partner instrument or aggregation device with which it communicates is determined.

  In addition, the upper limit of the number of hops and the upper limit of the number of instruments are changed according to the area where the automatic meter reading system is installed.

  Moreover, when installing an automatic meter-reading system in an urban area, the upper limit of the number of hops is made smaller than when installed in a county.

  According to the present invention, additional installation can be easily performed, and further, the number of data collection of the wireless communication terminal according to the installation location of the aggregation device can be maximized, and the number of aggregation device installation can be minimized. Cost reduction can be realized.

The figure which showed the example which additionally installed the electricity meter 3i in the network 5. FIG. The figure which showed the allocation of the time slot which communicates for interference prevention. The figure which showed the communication example of transmission of the meter-reading data from the watt-hour meter 3 to the aggregation apparatus 2. FIG. The schematic diagram which shows the whole structure of an automatic meter-reading system. The flowchart which selects a parent node from the received own node information. The figure which shows the specific example of self-node information Mg, Mh, Mc, and Md. The bird's-eye view which showed the communication range by the upper limit (D2) of the hop number under an aggregation apparatus. The figure which showed the example of the transmission timing of meter-reading data.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 4 is a schematic diagram showing the overall configuration of an automatic meter reading system to which the present invention is applied.
This automatic meter-reading system is a system that automatically collects meter-reading data of power usage from each power consumer, and includes a plurality of watt-hour meters 3, an aggregation device 2 that collects data of a plurality of watt-hour meters, and a plurality of watt-hour meters. And a management server 1 that manages a plurality of watt-hour meters 3. In the case of the present invention, the watt-hour meter 3 has a wireless communication function that enables wireless communication with the aggregation device 2 and the other watt-hour meters 3, and the metering data on the power consumption is periodically collected by the aggregation device 2. Send to.

  The watt-hour meter 3 is composed of a plurality of hierarchies, and is connected by a wireless network 5 in a tree shape with the aggregation device 2 as the highest level. The management server 1 is installed in, for example, a business office of an electric power company, and performs device management of the aggregation device 2 and the watt-hour meter 3. The aggregation device 2 is a device that is connected to the management server 1 via a network 4 by an optical fiber network, and connects the wireless communication network 5 with the watt-hour meter 3 and the optical fiber network 4 with the management server 1.

  The wireless communication network 5 between the aggregation device 2 and the electricity meter 3 is based on a multi-hop wireless network system. For example, when the aggregation device 2 has a hop number 1, the electricity meters 3a to 3e have a hop number 2. The watt hour meters 3f to 3g are in the order of 3 hops, and the watt hour meter 3h is 4 hops.

  Further, in this multi-hop wireless network system, the radio frequency f1 used by the electricity meters 3a, 3b, 3f, 3g, and 3h communicating with the aggregation device 2A and the wireless used by the electricity meter 3c communicating with the aggregation device 2B. The frequency f2 and the radio frequency f3 used by the watt-hour meters 3d and 3e communicating with the aggregation device 2C are different from each other. For this reason, it is necessary to prevent interference (communication collision) between the aggregation device 2 and the watt hour meter 3 that perform communication using the same radio frequency.

  FIG. 2 is a diagram showing allocation of time slots in which each person communicates in order to prevent interference in a wireless communication network. The data transmission time in the wireless communication network is time-divided, and the upstream communication time zone T1 for collecting meter reading data from each watt-hour meter 3 and the downstream communication for setting from the management server 1 to the watt-hour meter 3 The time periods T2 are repeated alternately. Thereby, it becomes possible to interrupt the downlink communication without causing a communication collision even during the meter reading data collection.

  FIG. 3 is a diagram illustrating a communication example of meter reading data transmission from the watt-hour meter 3 of FIG. 1 to the aggregation device 2. Here, an example is shown in which uplink communication is performed between the aggregation device 2 of FIG. 1 and 3h via the electricity meters 3a and 3g. The watt-hour meter 3h transmits meter-reading data to the watt-hour meter 3g, which is the parent node, in a predetermined upstream communication frame T1. The watt hour meter 3g that has received the meter reading data transmitted from the watt hour meter 3h transfers it to the watt hour meter 3a that is its parent node in the latest upstream communication frame T1. Furthermore, the watt-hour meter 3a that has received the meter reading data transmitted from the watt-hour meter 3g transfers it to the aggregation device 2A that is its parent node in the latest upstream communication frame T1. In this way, the meter reading data is transmitted by the specified upstream communication frame, and the meter reading data received from other watt-hour meters is transferred by the latest upstream communication frame, thereby delivering the meter reading data to the aggregation device.

  In the multi-hop wireless network system, wireless communication is performed while avoiding a communication collision by executing the network use of FIGS. 2 and 3 in the configuration of FIG. With reference to FIG. 1, the introduction of a new wireless terminal (electricity meter) and addition to the system due to the construction of a new house at the stage where the above-described power meter reading system has already been constructed will be described with reference to FIG. 1. .

  FIG. 1 is a diagram showing an example in which a watt hour meter 3 i is additionally installed in the network 5. The additionally installed watt-hour meter 3i needs to start wireless communication with one of the neighboring watt-hour meters 3 (or the aggregation device 2), and in this case, it is necessary to select an appropriate partner at its own judgment. . When the watt-hour meter 3i is installed in the house, it is possible for the builder to set an appropriate communication partner, but in the present invention, the watt-hour meter 3i itself determines.

  In order to enable this, the watt-hour meter 3 includes a receiver that switches and receives a plurality of frequencies (f1, f2, and f3 in the example of FIG. 1) used in the multi-hop wireless network system. In addition, a frequency higher than a predetermined reception sensitivity is selected. In the case of FIG. 1, the additionally installed watt-hour meter 3i can receive the frequencies f1, f2, and f3 with high sensitivity. In this example, the watt-hour meters 3g, 3h, 3c, and 3d can be intercepted. Suppose there is.

  On the other hand, the installed watt-hour meter 3 (or the aggregation device 2) includes its own node information M in the communication data communicated in the uplink / downlink communication time zone. Here, the self-node information M is self-advertisement information, and the contents included in the self-node information include the number of affiliated hops (D1), the upper limit of the number of hops under the aggregation device (D2), and belonging to the aggregation device The number of watt-hour meters (D3), and the upper limit (D4) of the number of watt-hour meters that can belong to the aggregation device.

  The watt-hour meter 3i newly installed in the consumer determines the optimum parent node by receiving the own node information periodically transmitted by the aggregation device 2 and each watt-hour meter 3. FIG. 5 shows a parent node determination program of the newly installed energy meter 3i.

  In the processing program of FIG. 5, first, in step S100, the watt-hour meter 3i of FIG. 1 receives its own node information transmitted by surrounding nodes for a specified time. Thereby, the own node information Mg, Mh, Mc, Md emitted from the watt-hour meters 3g, 3h, 3c, 3d is obtained. FIG. 6 shows an example of specific contents of the own node information Mg, Mh, Mc, and Md obtained at this time.

  In step S101, for the received local node information Mg, Mh, Mc, Md, the number of watt-hour meters (D3) under the aggregation device to which each watt-hour meter 3g, 3h, 3c, 3d belongs, and the aggregation device The upper limit (D4) of the number of watt-hour meters that can belong to the subordinates is compared, and it is determined whether to exclude from the parent node candidates. In the example of FIG. 6, since D3 (20) = D4 (29) is set for Mc, no further watt-hour meter 3 can be added to the aggregation device 2B, so connection to the watt-hour meter 3c is possible. Is eliminated.

  Furthermore, in step S102, the number of hops (D1) to which each watt-hour meter 3 belongs is compared with the upper limit (D2) of the number of hops under the aggregation device, and it is determined whether to exclude from the parent node candidates. In the example of FIG. 6, since D1 (4) = D2 (4) is set for Mh, the watt-hour meter 3 cannot be added to the aggregation device 2A at the position where the number of hops is four. Connection to 3h is eliminated.

  If no parent node candidate remains in step S103 (all connection destinations are denied in the above two conditions check), the process returns from NO to step S100, and again receives information on the surrounding local nodes for a specified time. Process.

  If the parent node candidate remains in step S103, in step S104, the node with the smallest number of affiliation hops is selected as the parent node from the remaining parent node candidates that are not excluded. In the example of FIG. 6, the own node information Mg and Md remain, but since the number of hops is (3) and (2), respectively, the watt hour meter 3d of Md is finally determined as the parent node. To do. At this time, the affiliation hop of the watt-hour meter 3i is (3), which is the number of hops obtained by adding (1) to the number of hops (2) of the parent node 3d.

  When the parent node is selected by the procedure of FIG. 5, the additional watt-hour meter 3i transmits a participation request to the watt-hour meter 3d selected as the parent node, and the watt-hour meter 3d that receives the participation request transfers it to the aggregation device 2C. . The aggregation device 2C allocates meter reading data transmission timing not to overlap with other watt meters 3 in response to the participation request from the watt hour meter 3d, and transmits the meter reading data transmission timing to the watt hour meter 3i.

Thereafter, the watt-hour meter 3i transmits its own meter reading data based on the assigned meter reading data transmission timing. Thereafter, the own node information Mi oscillated by the additional watt-hour meter 3i is D1 (3), D2 (5), D3 (16), and D4 (25).
In addition, even after the parent node is selected, information on the surrounding local node is periodically received, and the parent node is changed to the optimum parent node.

  As is apparent from the parent node determination logic of the additional watt-hour meter 3 described with reference to FIG. 6, whether or not connection is possible is determined according to the upper limits of D2 and D4. That is, whether to connect is determined by the upper limit of the number of hops and the number of connected devices. This determinant is changed depending on whether the automatic meter reading system is installed in an urban area or a district.

  FIG. 7 is an overhead view showing a communication range based on the upper limit (D2) of the number of hops under the aggregation device. The upper limit of the number of hops is set for each aggregation device 2 according to the installation location when the aggregation device 2 is installed. When the upper limit (D2) of the number of hops is large, the subordinate network range managed by one aggregation device becomes large, and when the upper limit (D2) of the hop number is small, the network range under the aggregation device becomes small. . For example, if the communicable distance between each node is 100 meters and the upper limit (D2) of the number of hops under the aggregation device is 3, the meter reading data of the watt-hour meter 3 within the radius of 300 meters from the aggregation device 2 is collected. It becomes possible. However, if the network range is large, the number of watt-hour meters 3 that can belong to the aggregation device 2 may exceed the upper limit (D4), so an appropriate upper limit (D2) of the number of hops is set. It is necessary.

  Based on this, in urban areas where electricity meters 3 are densely populated, the upper limit (D2) of the number of hops under the aggregation device is set small, and in counties where electricity meters are scattered, the number of hops under the aggregation device When the upper limit (D2) is set to be large, it is possible to optimally arrange the aggregation devices, and to minimize the number of aggregation devices installed.

  FIG. 8 is a diagram showing an example of the transmission timing of meter reading data transmitted from each watt-hour meter 3 under the aggregation device 2A shown in FIG. Here, the upper limit (D2) of the number of hops set in the aggregation device 2A is assumed to be 3. Each watt-hour meter 3 under the aggregation device 2A has a time slot for meter reading data transmission in advance, and the watt-hour meter 3a receives its meter reading data at a specified timing that does not overlap with other watt-hour meters 3. Transmit to the parent node 2A.

  Here, if communication between the aggregation device 2A and the watt-hour meter 3a is taken into consideration, one set of uplink and downlink communication frames may be prepared, but here, three sets of uplink and downlink communication frames are prepared. Prepare. In addition, other communication is not performed in the 3 time slots that are the meter reading data transmission time of the watt-hour meter 3a reserved in advance.

  Similarly, the watt-hour meter 3b transmits its meter reading data to the parent node at a specified timing that does not overlap with other watt-hour meters. Again, three sets of uplink and downlink communication frames are prepared. In this way, the same number of continuous uplink communication frames as the upper limit (D2) of the number of hops is secured for all watt-hour meters 3 under the aggregation device.

  Thereby, since a communication collision does not occur, meter reading data can be reliably collected. Further, even if the parent node is changed, it is not necessary to reset the meter reading data transmission timing, and communication traffic can be reduced.

  In addition, although the above description was introduced by the example which applied this invention to the automatic measurement of electric energy, it can apply similarly to the meter-reading of water supply besides electric energy. In the case of water supply, there are the same problems in building a system.

1: Management server 2: Aggregation device 3: Electricity meter 4: Network by optical fiber network 5: Wireless communication network T1: Up-communication time zone T2: Down-communication time zone f: Radio frequency M: Own node information

Claims (7)

In an automatic meter reading system connected between a plurality of meters having a wireless communication function and an aggregation device in a tree shape and connected by a multi-hop wireless network that communicates the meter or aggregation device on the aggregation device side as a parent node,
The instrument and the aggregation device transmit the upper limit of the number of hops of the multi-hop wireless network, the number of hops to which the instrument belongs, and the upper limit of the number of instruments and the number of connections included in its own communication data . In order to communicate between them, a time slot for performing communication between them in a predetermined time zone is set, and this time slot is a set of communication frames required for bidirectional communication performed continuously in time. Sometimes, for communication between the aggregation device and the instrument with the highest number of hops communicating with the aggregation device, the same number of communication frames as the upper limit of the hop number is provided,
After the meter or aggregation device with which it communicates is defined as a parent node, the meter periodically receives the communication data transmitted by the surrounding meter or aggregation device and changes the parent node. A featured automatic meter reading system. The automatic meter reading system according to claim 1,
The meter confirms the upper limit of the number of hops of the multi-hop wireless network included in the communication data transmitted by other instruments, the number of hops to which the instrument belongs, the upper limit of the number of instruments and the number of connected devices, An automatic meter reading system, wherein the meter or the aggregation device is determined as a parent node. The automatic meter reading system according to claim 2,
An automatic meter-reading system characterized by selecting a partner that does not exceed the upper limit of the number of hops and the upper limit of the number of connected devices when determining the parent node of the meter or aggregation device of the partner with which it communicates. Multi-hop communication between a plurality of instruments having a wireless communication function and a plurality of aggregation devices formed in a tree shape, with different radio frequencies for each aggregation device, and communicating the instruments or aggregation devices on the aggregation device side as a parent node In an automatic meter reading system connected by a wireless network,
The instrument and the aggregation device transmit the upper limit of the number of hops of the multi-hop wireless network, the number of hops to which the instrument belongs, and the upper limit of the number of instruments and the number of connections included in its own communication data . In order to communicate between them, a time slot for performing communication between them in a predetermined time zone is set, and this time slot is a set of communication frames required for bidirectional communication performed continuously in time. Sometimes, for communication between the aggregation device and the instrument with the highest number of hops communicating with the aggregation device, the same number of communication frames as the upper limit of the hop number is provided,
After the meter or aggregation device with which it communicates is defined as a parent node, the meter periodically receives the communication data transmitted by the surrounding meter or aggregation device and changes the parent node. A featured automatic meter reading system. The automatic meter reading system according to claim 4 ,
The meter switches the frequency used by itself and confirms the communication content of another meter or aggregation device, and determines the upper limit of the number of hops of the multi-hop wireless network included in the communication data transmitted by the other meter and the self. An automatic meter-reading system characterized in that, by using the number of connected hops, the upper limit of the number of instruments, and the number of connected instruments, the instrument or aggregation device with which the other communicates is determined as a parent node. An automatic meter reading system according to any one of claims 1 to 5,
An automatic meter reading system, wherein the upper limit of the number of hops and the upper limit of the number of instruments are changed according to a region where the automatic meter reading system is installed. The automatic meter reading system according to claim 6 ,
The automatic meter-reading system is characterized in that when the automatic meter-reading system is installed in an urban area, the upper limit of the number of hops is reduced compared to when the automatic meter-reading system is installed in a county.

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