JP5905255B2 - Energy meter for automatic meter reading - Google Patents

Description

The present invention relates to an automatic meter reading watt equipped with a radio communications device you wireless communication power amount data metered by the power meter.

  Conventionally, in order to communicate data measured by a measuring instrument, a watt-hour meter which is a kind of measuring instrument may use a power line communication (PLC) method. The watt-hour meter installed in the power distribution system and supplied with commercial power uses a clock pulse synchronized with the commercial power frequency when measuring time. Since the frequency of the commercial power supply is accurately controlled, a highly accurate clock can be easily obtained by using a clock pulse generated from the commercial power supply. On the other hand, when a wireless communication method is used to communicate data measured by the measuring instrument and communication is performed using a wireless communication device to which no commercial power is supplied, the time measurement pulse is generated from the output waveform of the crystal resonator.

  Conventionally, there is a timepiece disclosed in Patent Document 1 as a technique for obtaining a clock pulse from a commercial power source. This watch detects the radiated electromagnetic field of a commercial power source that is induced in the space where we live, by means of a coil with an iron core. The AC signal of the commercial power supply frequency detected by the coil containing the iron core is amplified by the amplifier circuit, and is input to the timer circuit and divided. The digital display is driven by this divided signal and displays time.

JP-A-10-282269

  However, the above-described conventional wireless communication device that communicates the measurement data by the wireless communication method is inferior to the case of using the commercial power supply frequency because the time measurement accuracy depends on the oscillation frequency accuracy of the crystal resonator. To avoid this, when a wireless communication device is connected to a commercial power supply, a power supply circuit such as a transformer is newly required inside the wireless communication device, and it is necessary to secure an insulation distance in the circuit board. Will become larger.

  Moreover, although the timepiece disclosed in Patent Document 1 uses a radiated electromagnetic field of a commercial power source induced in a living space, electromagnetic waves of the commercial power source are extremely small except under a high-voltage power transmission line or in the vicinity of a power line. For this reason, in order to detect such a weak electromagnetic wave, a large iron-core coil at least larger than a power transformer is required. The electromagnetic wave of the commercial power supply frequency component in the living space is a combination of electromagnetic waves from various sources such as electromagnetic waves from many power lines and spontaneously phase differences such as reflected waves. For this reason, it is difficult to detect a highly accurate commercial power supply frequency waveform from the living space.

The present invention has been made to solve such problems,
A watt hour meter is connected to the power supply side terminal to which the power supply side power supply line that receives the supply of the commercial power supply is connected, and the load side power supply line to supply the commercial power supply to a plurality of load devices in the house. A load-side terminal connected to the power-side terminal, an energy metering unit that is connected to the internal power supply line by an internal wire and measures the amount of power consumed by multiple load devices in the house, and energy metering Automatic measurement of total electricity consumption data for each house and automatic meter reading for each house, comprising a wireless communication device that wirelessly transmits electricity measurement data measured by the unit to the outside In the watt-hour meter for automatic meter reading used in the meter reading system,
A sensor that detects at least one of an electric field or a magnetic field of a commercial power supply generated in the internal power supply line, the internal electric wire, or the power supply side power supply line
Radios, comprises a timing pulse generating means to generate at least one detection signal or al meter Pulse of detected electric or magnetic field by the sensor, is provided inside or outside the power meter power meter, timekeeping Time is measured using the time-measurement pulse generated by the pulse generation means.

According to this configuration, the sensor is different from the case of detecting a weak electromagnetic wave of the commercial power supply frequency component in the living space, and the power-side power supply line or the internal power supply line or the internal electric wire that supplies the commercial power to the load device . Ensure electromagnetic coupling. For this reason, the sensor does not require a large iron-core coil or the like, and suppresses interference from other electromagnetic waves that become noise, and at least one of the electric field or magnetic field of the commercial power supply is connected to the internal power supply line or the internal It can be reliably detected from the electric wire or the power supply line on the power source side . Therefore, high accuracy of the commercial power frequency waveform is obtained, clocking pulse generating means may generate a total time of pulse with high accuracy based on this waveform. As a result, unnecessary to the internal power supply circuit wireless communication device of the transformer or the like, there is no need to ensure an insulation distance at the circuit board, an automatic meter reading with a radio communications device count the time in small and high precision An electricity meter is provided. In addition, the power consumption measuring unit that measures the amount of power has a stable power consumption, and a drive current that drives the power measurement unit stably flows through the internal electric wire that supplies the commercial power to the power measurement unit. For this reason, when the sensor detects the magnetic field of the commercial power generated in the internal electric wire, the sensor detects the stable magnetic field formed by the drive current that stably flows in the internal electric wire. A frequency waveform can be detected.

Further, the present invention, the sensor, characterized in that the electrically insulated from the internal power supply line or the inner wires or power-side power supply line is installed in or out of the housing for accommodating the radio communications device And

According to this construction, since the sensor is electrically insulated from the internal power supply line or the inner wires or power-side power supply line, a wireless communication device occurs in internal power supply line or the inner wires or power-side power supply line Not affected by lightning strikes. In addition, since the sensor is installed in a housing that houses the wireless communication device, handling of the wireless communication device is facilitated. In addition, by installing the sensor outside the housing that houses the wireless communication device, the sensor can be brought closer to the internal power supply line , the internal electric wire, or the power supply side power supply line. Alternatively, the commercial power supply frequency can be obtained more reliably by further strengthening the electromagnetic coupling with the power supply side power supply line .

Further, the present invention is characterized in that the sensor detects a magnetic field generated in a coil formed in a part of the internal electric wire.

According to this configuration, the magnetic field formed on the internal electric wire by the drive current is increased by the coil formed on a part of the internal electric wire. For this reason, since the sensor detects the magnetic field enlarged by the coil, it becomes possible to efficiently detect the magnetic field of the commercial power supply, and to detect the commercial power supply frequency waveform more accurately.

Further, the present invention is characterized in that the sensor detects the electric field of the commercial power supply by dividing the commercial power supply voltage applied to the internal power supply line or the power supply side power supply line with a capacitor.

According to this configuration, the sensor does not detect the electromagnetic wave of the commercial power supply propagating in the space, but directly from the capacitor that divides the commercial power supply voltage applied to the internal power supply line or the power supply side power supply line . Detect the electric field. For this reason, it is possible to reliably and accurately detect the commercial power supply frequency waveform without receiving interference from noise electromagnetic waves propagating in space.

According to the present invention, as described above, unnecessary to the internal power supply circuit wireless communication device of the transformer or the like, there is no need to ensure an insulation distance at the circuit board, no line you count the time in small and high precision An watt-hour meter for automatic meter reading provided with a communication device is provided .

It is a schematic block diagram of the watt-hour wireless communication apparatus by one embodiment of this invention. (A) is a block diagram which shows the structure of the time-measurement pulse production | generation means in the radio | wireless communication apparatus shown in FIG. 1, (b) is a block diagram which shows the structure of the time-measurement pulse production | generation means in the conventional watt-hour meter. 1 shows a modification of the sensor constituting the wireless communication device shown in FIG. 1, (a) is a modification of the sensor installed in the vicinity of the power supply line, and (b) is installed connected to the power supply line. It is a figure which shows the modification of a sensor. It is a system block diagram of the automatic meter-reading (AMR) using the watt-hour meter with which the radio | wireless communication apparatus shown in FIG. 1 is attached. It is a block diagram which shows the example of a cooperation with AMR and a home energy management system (HEMS). It is a timing chart figure of each signal in the example of cooperation of AMR and HEMS shown in FIG.

  Next, an embodiment in which the wireless communication device for measuring instrument according to the present invention is applied to the wireless communication device for watt hour meter will be described.

  FIG. 1 is a schematic configuration diagram of a watt-hour wireless communication device according to the present embodiment.

  The wireless communication device 1 is built in the watt hour meter 2 and attached to the watt hour meter 2. Power supply lines 3a, 3b, 3c are connected to the power supply side terminals 1S, 2S, 3S of the watt hour meter 2, and commercial power is supplied to the watt hour meter 2 through the power supply lines 3a, 3b, 3c. The In addition, power supply lines 4a, 4b, 4c are connected to the load side terminals 1L, 2L, 3L of the watt-hour meter 2, and power is supplied to load devices (not shown) via the power supply lines 4a, 4b, 4c. Is done. The power supply side terminals 1S, 2S, 3S and the load side terminals 1L, 2L, 3L are connected to each other by the power supply lines 5a, 5b, 5c inside the watt hour meter 2.

  The watt hour meter 2 includes a power amount measuring unit 6. The electric energy metering unit 6 is supplied with commercial power from the electric wires 7a, 7b, 7c connected to the power supply lines 5a, 5b, 5c, and is consumed by the load equipment connected to the power supply lines 4a, 4b, 4c. Measure the amount of electric power. The power amount measuring unit 6 outputs the measured power amount data to the wireless communication device 1. The wireless communication device 1 is not supplied with commercial power and has a built-in battery. The wireless communication device 1 operates using the built-in battery as a drive source, and wirelessly communicates the energy data measured by the energy meter 6 with the outside. In the present embodiment, the wireless communication device 1 is provided with a sensor 8 composed of a high-impedance coil L outside the casing that houses the wireless communication device 1. The sensor 8 is electrically insulated and separated from the power supply line 5a and is installed in the vicinity of the power supply line 5a, and detects the magnetic field of the commercial power generated in the power supply line 5a. In addition, the wireless communication device 1 is provided with a time pulse generation means 9 for generating a time pulse of a commercial power frequency from a magnetic field detection signal detected by the sensor 8.

  FIG. 2A is a block diagram showing the configuration of the time-measurement pulse generating means 9. The time pulse generation means 9 includes a waveform shaping circuit 9a, a low pass filter (LPF) 9b, and a clock pulse circuit 9c. The waveform shaping circuit 9a shapes the waveform of the magnetic field detection signal output from the sensor 8 using a high impedance amplifier circuit, and outputs the waveform to the low pass filter 9b. The low-pass filter 9b extracts a commercial frequency component from the signal shaped by the waveform shaping circuit 9a and outputs it to the clock pulse circuit 9c. The clock pulsing circuit 9c uses a comparator or the like to generate a time measuring pulse from the commercial power supply frequency component extracted by the low pass filter 9b. The watt-hour meter 2 performs an operation based on the time using the time pulse generated by the time pulse generation means 9.

  FIG. 2 (b) is a block diagram showing a configuration of a time pulse generating means in a conventional watt hour meter that communicates measurement data by the PLC method. Conventionally, the commercial frequency power supply 11 of the watt-hour meter is stepped down by the step-down circuit 12 and a clock pulse is generated from the stepped-down commercial frequency voltage signal by the clock pulsing circuit 13.

  According to the watt-hour wireless communication device 1 according to this embodiment, the sensor 8 is different from the conventional case in which a weak electromagnetic wave of the commercial power supply frequency component in the living space is detected. It is surely electromagnetically coupled to the power supply line 5a for supplying commercial power. For this reason, the sensor 8 does not require a large iron-cored coil as used in the timepiece disclosed in Patent Document 1, and further suppresses interference from other electromagnetic waves that become noise, thereby reducing the commercial power supply. The magnetic field can be reliably detected from the power supply line 5a. Therefore, a highly accurate commercial power supply frequency waveform can be obtained by the waveform shaping circuit 9a, and the clock pulsing circuit 9c can generate a clock pulse of the commercial power supply frequency with high precision based on this waveform. As a result, there is provided a watt-hour wireless communication device 1 that does not require a power supply circuit such as a transformer inside the device and does not need to secure an insulation distance in the circuit board, and that measures time with high accuracy.

  Further, in the present embodiment, since the sensor 8 is electrically insulated and separated from the power supply line 5a, the wireless communication device 1 is not adversely affected by a lightning strike or the like generated on the power supply line 5a. Further, since the sensor 8 is installed outside the casing that houses the wireless communication device 1, the sensor 8 can be brought closer to the power supply line 5a, and the electromagnetic coupling with the power supply line 5a can be further strengthened. The commercial power supply frequency can be obtained with certainty.

  In the above-described embodiment, the case where the sensor 8 is configured by the coil L and is installed close to the power supply line 5a has been described. However, the sensor 8 need not be limited to the coil L, and may detect at least one of an electric field or a magnetic field generated in the power supply line 5a. The high-impedance capacitor C or the coil L shown in FIG. It may be configured like an antenna by a composite element F of a capacitor C. The sensor 8 detects the electric field of the commercial power source when it is configured by the capacitor C, and detects the electromagnetic field of the commercial power source when it is configured by the composite element F. In this case, the time pulse generation means 9 generates a time pulse of the commercial power frequency from the detection signal of at least one of the electric field or magnetic field detected by the sensor 8.

  In the above-described embodiment, the case where the sensor 8 is installed outside the casing that houses the wireless communication device 1 has been described. However, the sensor 8 may be configured to be installed in a casing that houses the wireless communication device 1. According to this configuration, since the sensor 8 is installed in the housing that houses the wireless communication device 1, the wireless communication device 1 can be easily handled.

  In the above embodiment, the case where the sensor 8 is installed in the vicinity of the power supply line 5a has been described. However, as shown in FIG. 3B, the sensor 8 divides the commercial power supply voltage applied between the power supply line 5a and the ground line 10 with the capacitors C1 and C2, and drops the commercial power supply voltage with the capacitor C2. You may comprise so that an electric field may be detected. In this case, the sensor 8 is composed of capacitors C 1 and C 2, and both ends of the capacitor C 2 are connected to a signal line exiting from the wireless communication device 1. According to this configuration, the sensor 8 does not detect the electromagnetic wave of the commercial power supply propagating in the space, but detects the electric field of the commercial power supply directly from the capacitor C2 that divides the commercial power supply voltage applied to the power supply line 5a. . For this reason, it is possible to reliably and accurately detect the commercial power supply frequency waveform without receiving interference from noise electromagnetic waves propagating in space.

  Further, in the above embodiment and the modification, the case where the electric field or magnetic field formed by the capacitor C or the coil L installed around the power supply line 5a is detected has been described. However, you may comprise so that the electric field or magnetic field formed with the capacitor | condenser C or the coil L installed around the electric power supply lines 5b and 5c may be detected.

  Moreover, you may comprise so that the magnetic field which generate | occur | produces in electric wire 7a, 7b, 7c which supplies a commercial power supply to the electric energy metering part 6 instead of electric power supply line 5a, 5b, 5c may be detected. A load current corresponding to the load amount flows through the power supply lines 4a, 4b, and 4c on the load side of the watt hour meter 2, and the magnitude of the load current constantly changes. However, the power consumption measuring unit 6 that measures and displays the electric energy has stable power consumption, and the electric energy measuring unit 6 is connected to the electric wires 7a, 7b, and 7c that supply commercial power to the electric energy measuring unit 6. The driving current for driving flows stably. For this reason, according to said structure, the sensor 8 will detect the stable magnetic field which the drive current which flows into the electric wires 7a, 7b, and 7c stably forms, and can detect a commercial power supply frequency waveform exactly. I can do it.

  In the above configuration for detecting the magnetic field generated in the electric wires 7a, 7b, and 7c, the sensor 8 is configured to detect the magnetic field generated in a coil formed in a part of the electric wires 7a, 7b, and 7c. Also good. In this case, the sensor 8 is configured by a coil or the like that is electromagnetically coupled to a coil formed in a part of the electric wires 7a, 7b, and 7c. According to this configuration, the magnetic field formed in the electric wires 7a, 7b, and 7c by the drive current is increased by the coil formed in a part of the electric wires 7a, 7b, and 7c. For this reason, since the sensor 8 detects the magnetic field enlarged by this coil, it becomes possible to detect the magnetic field of a commercial power supply efficiently, and to detect a commercial power supply frequency waveform more accurately. .

  In the above embodiment, the case where the wireless communication device 1 is built in the watt hour meter 2 and attached to the watt hour meter 2 has been described. However, the wireless communication device 1 may be configured to be installed outside the watt hour meter 2 and attached to the watt hour meter 2. In this case, the sensor 8 can detect an electric field or a magnetic field formed by the capacitor C or the coil L installed around the external power supply lines 3a, 3b, 3c. Further, it is also possible to detect the electric field of the commercial power source obtained by dividing the commercial power supply voltage applied between the power supply lines 3a, 3b, 3c and the ground line 10 by the capacitors C1 and C2 and reducing the voltage by the capacitor C2.

  Automatic meter reading (AMR: Automatic Meter Reading) using the watt-hour meter 2 to which the wireless communication device 1 is attached is performed by, for example, a system shown in FIG.

  In this system, hundreds of watt-hour meters 2 installed in each house 31a, 31b,... Are connected to one concentrator 21, and power measurement data is aggregated by multi-hop transmission. When data transmission is performed by wireless communication of the wireless communication device 1 in such a network constituted by a large number of terminals of the watt-hour meter 2, the available channel (ch) is confirmed by carrier sense in order to avoid interference. Weighing data will be transmitted later, but problems such as hidden terminal problems and prolonged carrier sense time still remain. In order to solve these problems, methods such as designation of a transmission terminal by polling and allocation of data transmission time can be considered, but since the specification of the former transmission terminal leads to an increase in communication traffic, the method of allocating the latter data transmission time Seems desirable. However, when this method is used, if the times of the wireless communication devices 1 in all watt-hour meters 2 are not synchronized, an unintended communication collision occurs, and the time division effect cannot be obtained.

  FIG. 5 is a block diagram illustrating an example of cooperation between the above-described AMR and a home energy management system (HEMS). In the figure, the same or corresponding parts as in FIG.

  HEMS connects multiple devices such as air conditioner / lighting 32, TV / refrigerator 33, solar cell (PV) 34, electric vehicle (EV) 35, etc., which are energy consuming devices in a house 31, through a home sensor network, and a control device 36 automatically controls. Further, the amount of power used by each device and the operation of each device are measured and displayed on the home display 37. The watt-hour meter 2 transmits the integrated power amount and the used power amount to the home display 37 and the control device 36 during a time period when AMR is not performed. At that time, real-time characteristics are lacking in information transmission at intervals of 30 minutes such as AMR. For example, even if the air conditioner / lighting 32 is stopped, the power consumption display on the home display 37 is not immediately reduced. For this reason, in HEMS, information is transmitted at intervals of several seconds. Signal transmission for HEMS control must be performed during this information transmission, and in order to perform transmission accurately in a short time, accurate time synchronization between devices is generated by the above-described time-measurement pulse generation in the wireless communication device 1. This is performed based on the time-measurement pulse generated by the means 9.

  FIG. 6 is a timing chart of each signal in the above example of cooperation between AMR and HEMS.

  The figure (a)-(c) has shown the signal transmission timing performed with the watt-hour meter 2 for each house 31a, 31b, ..., 31h. FIG. 4D shows a time zone in which AMR is performed and a time zone in which HEMS is performed. FIG. 4E shows the signal transmission timing in each house 31 in the HEMS time zone. As shown in FIGS. 5A to 5C, in the signal transmission in the AMR time zone, each watt-hour meter 2 transmits its own data D after confirming the vacant channel used by carrier sense C. . Further, as shown in FIG. 4E, in the HEMS time zone, the control device 36 in the house 31 receives the power amount data D from the watt hour meter 2 at intervals T of several seconds. The control data S for HEMS control is performed during the transmission of information at intervals of several seconds T.

  Here, for example, it seems that the watt-hour meter 2 in the house 31a may move to HEMS after performing its own AMR. However, since there is a possibility of collision with other AMR communication, it is not possible to shift to HEMS communication. For this reason, information cannot be provided to the HEMS during AMR, and the above-mentioned lack of real time occurs. In order to avoid this, methods such as separation of AMR and HEMS use channels, time division of AMR, and use of multiple channels can be considered. These also require time synchronization by ch change timing (ch control) and time division control. According to the watt-hour meter 2 of the present embodiment, accurate time synchronization can be performed based on the time pulse generated by the time pulse generation means 9 described above in the wireless communication device 1 as described above.

  As a wireless network time synchronization method, NTP (Network Time Protocol), which is a synchronization method considering the transmission time between a server and a client, is generally used, but this requires a plurality of time-synchronized servers. In addition, in a wireless sensor network such as AMR, the transmission timing cannot be accurately determined in advance, so that a certain amount of error occurs. Currently, as a time synchronization method with improved accuracy, a method such as RBS (Reference Broadcast Synchronization) which obtains time synchronization by time broadcast and time correction between adjacent terminals has been proposed. RBS is a method that can be expected to have synchronization accuracy on the order of microseconds, but has a disadvantage that communication traffic for correction cannot be ignored in a large-scale network. At present, the NTP that considers the adjacent watt-hour meter that is in operation as a server at the time of installation of the watt-hour meter and that maintains it with a high-accuracy clock is proposed as a feasible way to reduce communication traffic However, there is a possibility that the accuracy of RBS may be required as information traffic increases in the future.

  As described above, as AMR expands in the future and cooperation between AMR and HEMS advances, highly accurate time synchronization and its maintenance are indispensable for improving system quality. This requires an environment in which each device can use accurate timing pulses. Therefore, the present invention that can provide an accurate timing pulse contributes to an improvement in system quality.

DESCRIPTION OF SYMBOLS 1 ... Wireless communication device 2 ... Electricity meter 3a, 3b, 3c, 4a, 4b, 4c, 5a, 5b, 5c ... Electric power supply line 6 ... Electric energy metering part 7a, 7b, 7c ... Electric wire 8 ... Sensor 9 ... Timekeeping Pulse generation means 9a ... Waveform shaping circuit 9b ... Low pass filter (LPF)
9c: Clock pulse circuit

Claims (4)

A watt hour meter is connected to the power supply side terminal to which the power supply side power supply line that receives the supply of the commercial power supply is connected, and the load side power supply line to supply the commercial power supply to a plurality of load devices in the house. A load side terminal connected to the power source side terminal, an electric energy measuring unit connected to the internal power supply line by an internal wire, and measuring the amount of power consumed by a plurality of load devices in a house, Comprised of a wireless communicator that wirelessly transmits power measurement data measured by the power meter to the outside. In the watt-hour meter for automatic meter reading used in the automatic meter reading system for meter reading,
A sensor that detects at least one of an electric field or a magnetic field of a commercial power supply generated in the internal power supply line or the internal electric wire or the power supply side power supply line ;
The wireless communication device is provided with a timing pulse generating means to generate at least one detection signal or al meter Pulse of detected electric or magnetic field by the sensor is disposed in or outside the power meter wattmeter An automatic meter-reading watt-hour meter characterized in that the time is measured using the time-measurement pulse generated by the time-measurement pulse generation means. The sensor wherein the internal power supply line or the inner wire or the the power-side power supply line and electrically insulated and separated, is placed into or out of the housing for accommodating the front quinic line communicator The watt-hour meter for automatic meter reading according to claim 1 . The watt-hour meter for automatic meter reading according to claim 2 , wherein the sensor detects a magnetic field generated in a coil formed in a part of the internal electric wire. 2. The electric power for automatic meter reading according to claim 1, wherein the sensor detects an electric field of a commercial power source by dividing a commercial power source voltage applied to the internal power supply line or the power supply side power supply line with a capacitor. Total .

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