JP5857583B2 - Electric energy measurement system and electric energy meter - Google Patents

Description

  The present invention relates to a system and a watt hour meter that measure the amount of power of a consumer.

  In the electric power system, it is monitored whether the voltage of each part of the system is normal. For such monitoring, a technology of power line communication (PLC) is used. In recent years, in order to automate the metering of electric energy, a technique (for example, refer to Patent Document 1) in which the watt hour meter itself performs “meter reading” and transmits electric energy measurement data has been partially introduced. .

JP 2001-281269 A

However, when a plurality of power line communications are mixed, mutual interference of signals occurs, and it is expected that each communication will be hindered.
In view of such a problem, an object of the present invention is to provide an electric energy measuring system and an electric energy meter in consideration of mutual interference of signals of power line communication.

(1) A power amount measurement system of the present invention is provided in a communication master unit capable of injecting and extracting signals for power line communication via a main power line that distributes power to a plurality of power lines; A communication slave that can communicate with the master by power line communication, comprising a watt hour meter that measures a power amount related to the consumer and transmits a measurement data signal to the communication master, the communication master and the communication device The watt hour meter is characterized in that it communicates with each other while avoiding the time when power line communication for other purposes than the measurement of the electric energy is performed.
More precisely, the scope of the present invention is indicated by the claims.

  In the above power amount measurement system, a special communication line is not required, and power line communication related to power amount measurement can be performed while preventing mutual interference with signals of other target power line communication.

(2) In the electric energy measurement system of (1), the communication master unit instructs the watt hour meter to transmit a measurement data signal, and the watt hour meter transmits the measurement data signal in response to the instruction. You may make it transmit to a communication main | base station.
In this case, the communication master unit can acquire the measurement data signal whenever necessary.

(3) Moreover, in the electric energy measurement system of the above (1), the electric energy meter may transmit a measurement data signal to the communication base unit when a predetermined time comes.
In this case, even if there is no command from the communication base unit, the measurement data signal can be transmitted periodically.

(4) In the power measurement system according to (1) or (2), when the communication master detects an accident in the connected power system, power line communication with the watt hour meter is interrupted. It is preferable.
In this case, even when an open / close control signal is transmitted by power line communication, the signal and a signal related to power amount measurement do not interfere with each other.

  (5) On the other hand, the present invention is a communication slave that can communicate with a communication master by power line communication, and is provided in a consumer, and measures the amount of power related to the consumer and transmits a measurement data signal. The meter is characterized in that a measurement data signal is transmitted to the communication base unit while avoiding a time when power line communication for purposes other than the measurement of electric energy is performed.

  In the watt-hour meter described above, no special communication line is required, and power line communication related to power amount measurement can be performed while preventing mutual interference with other target power line communication signals.

  According to the power amount measurement system or the power meter of the present invention, it is possible to perform power line communication related to power amount measurement while preventing mutual interference of signals of power line communication.

It is a block circuit diagram which shows the electric energy measurement system which concerns on one Embodiment of this invention, and the watt-hour meter used for this with an electric power system diagram. It is a figure which shows the example of the timing which transmits the signal regarding electric energy measurement.

  FIG. 1 is a block circuit diagram showing an electric energy measuring system and an electric energy meter used therefor according to an embodiment of the present invention together with an electric power system diagram. This electric energy measurement system is installed for consumers, such as a general household, a store, and a building, for example. Here, it is typically described as a system used in a general household.

  In FIG. 1, a watt hour meter 2 and a distribution board 3 are provided in each of a plurality (two shown) of consumers 1 as viewed from the power supply side. A load such as a home appliance is connected to the lower part of the distribution board 3 via an indoor wiring. The watt-hour meter 2 is installed under the eaves or on a pole in the premises of the house. The watt-hour meter 2 incorporates a function as a PLC modem (function as a communication slave unit) that performs power line communication with the communication base unit 52 described later, in addition to a digital power amount measurement function. Each watt-hour meter 2 has a unique identification number, and the communication master device 52 can communicate with each watt-hour meter individually.

As power line communication for measuring electric energy, there are one using a signal having a frequency of 1 kHz or more and one using a signal having a frequency of less than 1 kHz. The lower frequency is suitable for long-distance transportation such as a power system.
For example, a TWACS (Two-Way Automatic Communications System) that superimposes a 1 or 0 digital signal in the vicinity of the zero cross of a commercial AC waveform is suitable as a method of low-frequency power line communication.

  The plurality of consumers 1 as described above are connected to the low piezoelectric path L2. A general household is usually supplied with 200V / 100V as a commercial AC voltage via a single-phase three-wire low piezoelectric path L2 (only two wires are shown for simplicity). In the case of a detached house, this voltage is generally supplied from a pole transformer 4 that transforms a high voltage of 6.6 kV to a low voltage of 200/100 V. A plurality of pole transformers 4 are installed in each district (only two are shown), and each has a plurality of customers.

  There is a substation 5 above the pole transformer 4. In the substation 5, for example, a distribution transformer 51 for transforming a special high voltage of 77 kV to a high voltage of 6.6 kV is installed. A voltage is applied from the distribution transformer 51 to the pole transformer 4 through a high piezoelectric path L1 (usually three-phase three-wire or four-wire but two wires are shown for simplification). That is, the high piezoelectric path L1 is a main power line that distributes power to a plurality of low-voltage power lines via the pole transformer 4.

In the substation 5, a communication master device 52, which is a PLC modem, is installed. The communication master unit 52 injects a power line communication signal into the high piezoelectric path L1 or extracts a signal from the high piezoelectric path L1 by the signal superimposing method described above, so that the communication of each house is performed via the pole transformer 4 and the low piezoelectric path L2. It is possible to perform power line communication with the watt-hour meter 2 as a slave unit.
The communication master unit 52 is connected to the monitoring device 6 that monitors the power system and collects information through a communication cable. Such a monitoring device 6 is typically installed in a central command room of an electric power company or the like.

Next, an electric energy measurement system in the electric power system configured as described above will be described.
The measurement of the electric energy can be performed based on, for example, a command given from the communication master device 52 to each watt hour meter 2. That is, the communication master device 52 transmits a command signal for measuring the electric energy to each watt-hour meter 2 when necessary. For example, transmission is performed in order at different timings for each watt-hour meter. The watt-hour meter 2 that has received the command signal measures an instruction value of the current power amount, and transmits the measurement data signal to the communication master unit 52 together with its own identification number. The communication master device 52 transmits the received measurement data signal to the monitoring device 6. By performing such a procedure for each watt-hour meter, it is possible to measure the power amount without requiring a special communication line. Further, the communication master device 52 can acquire a measurement data signal whenever necessary.

  There may be various methods other than the above for the communication procedure related to the measurement of the electric energy. For example, a measurement command signal is transmitted from the communication base unit 52 to all watt-hour meters under the control of the substation 5 in a broadcast manner, and each watt-hour meter is sequentially transmitted according to the order of responses assigned to itself. The measurement data signal may be transmitted to the communication base unit 52.

  In addition, the measurement data signal may be transmitted spontaneously from each watt-hour meter 2 without depending on the command from the communication master device 52. For example, the time for measuring the electric energy is determined in advance for each watt-hour meter 2, and the time is stored in each watt-hour meter. Each watt-hour meter 2 measures the amount of electric power when a predetermined time comes, and transmits the measurement data to the communication master unit 52. By shifting the determined time by each watt-hour meter, it is possible to prevent the measurement data from being simultaneously transmitted from a plurality of watt-hour meters. In this case, the measurement data signal can be periodically transmitted from each watt-hour meter 2 even if there is no specific command from the communication master device 52.

On the other hand, in the electric power system, power line communication is performed in addition to power amount measurement. For example, a signal for checking whether or not the voltage of each part below the substation 5 is normal, and an open / close signal such as shut-off and re-injection in the event of a power system failure are transmitted and received by power line communication. These are superimposed on the commercial alternating current as, for example, a sine wave signal having a minute amplitude with a frequency higher than that of the commercial power supply.
Therefore, it is necessary to measure the amount of electric power in consideration of other power line communication situations.

  FIG. 2 is a diagram illustrating an example of the timing at which the command signal So for measuring the electric energy is transmitted. When there is a signal that is periodically transmitted, such as the voltage check signal Sx (t1 to t2, t3 to t4) shown in FIG. 2 (a), it is between the times t2 and t3 that are in between. The communication master device 52 transmits a command signal So. The communication base unit 52 constantly monitors the signal of the power line communication, and when there is a possibility that the other power line communication is performed, the signal is transmitted at a time when the target signal is not transmitted. . Similarly, the watt-hour meter 2 on the handset side monitors the signal of the power line communication, and when there is a possibility that another target power line communication is performed, the measurement is performed at the time when the target signal is not transmitted. The data signal Sm is transmitted. In this way, it is possible to measure the electric energy while reliably preventing mutual interference with other power line communication signals.

  In addition, in FIG. 2B, when a power system accident (for example, ground fault) occurs at time t11, the associated switch is once opened and sequentially reapplied. If the location of the cause of the accident can be identified in the process of recharging, control such as energizing the system that can be energized by another route while avoiding energization to that location is performed. The time zone Δt (t11 to t12) in which such a switching control signal Sy may be transmitted as power line communication is empirically and statistically known.

  Therefore, the power line communication for measuring the electric energy is interrupted during such a time zone Δt. When the return from the accident is confirmed at time t12, power line communication for measuring the electric energy is resumed at a time t13 after a predetermined time, and a measurement command signal So (or measurement data signal Sm) is transmitted. Even when the opening / closing control signal Sy is transmitted by power line communication due to such interruption of the predetermined time, the signal Sy and the signal related to the power amount measurement do not interfere with each other.

  For example, when the communication master device 52 (or the watt-hour meter 2) detects the recovery from the accident at time t12, the command signal So (or the measurement data signal Sm) at time t13 after a certain time has elapsed since the recovery. ) Is transmitted more reliably, while avoiding mutual interference with other power line communication signal Sy.

  Since the other power line communication signals (Sx, Sy) and the power amount measurement command signal So (or measurement data signal Sm) have different signal superposition methods as described above, the communication master unit 52 And each electric energy meter 2 can selectively receive only the signal (So, Sm) regarding electric energy measurement.

  According to the electric energy measurement system and the electric energy meter 2 as described above, the power line communication related to the measurement of the electric energy can be performed while preventing the mutual interference with the signal of the other power line communication. Further, it is not necessary to newly provide a communication line for measuring the electric energy by using the power lines (L1, L2).

  In addition, in the said embodiment, although the place where the communication main | base station 52 is installed in the substation 5 is suitable at the point which inject | pours the signal for power line communication with respect to the main power line which distributes to a several power line, it does not necessarily have substation. It is not necessarily limited to the place 5.

  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 Consumer 2 Electricity meter (Communication cordless handset)
52 Communication Master L1 Low Piezoelectric Road (Power Line)
L2 High piezoelectric road (main power line)

Claims (5)

A communication master unit capable of signal injection and signal extraction for power line communication via a main power line that distributes power to a plurality of power lines,
A communication slave unit provided in each of a plurality of consumers and capable of communicating with the communication master unit by power line communication, and measuring a power amount related to the consumer and transmitting a measurement data signal to the communication master unit With a meter,
The communication base unit and each watt hour meter monitor a signal of power line communication, avoid a time when there is a possibility that power line communication for purposes other than the measurement of power amount is performed, and each watt hour meter A power amount measurement system characterized in that the communication is performed with respect to the measurement of the power amount with each other at different timings .   The communication master unit commands the watt-hour meter to transmit the measurement data signal, and the watt-hour meter transmits the measurement data signal to the communication master unit in response to the command. Electric energy measurement system.   The electric energy measurement system according to claim 1, wherein the electric energy meter transmits the measurement data signal to the communication master unit when a predetermined time comes.   The electric energy measurement system according to any one of claims 1 to 3, wherein when the communication base unit detects an accident in a connected electric power system, electric power line communication with the electric energy meter is interrupted. It is a communication slave that can communicate with a communication parent device by power line communication, and is a watt-hour meter that is provided in a consumer and measures a power amount related to the consumer and transmits a measurement data signal.
Monitor the signal of the power line communication, avoid the time when the power line communication for other purposes other than the measurement of the electric energy may be performed, and at the timing given to the watt hour meter , A watt-hour meter that transmits a measurement data signal.

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