JP2015135319A - Power measurement device, and power measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power measurement device easy to be mounted, which is a non-contact measurement device and does not require power source equipment.SOLUTION: A power measurement device comprises clamp type detectors each comprising: a magnetic core disposed so as to surround an outer periphery of a power line; a current detection coil wound around the magnetic core; and electrodes for detecting voltage, which is attached to an inner periphery of the magnetic core, for detecting a current and a voltage of the power line and calculating a power. The power measurement device comprises: two clamp type detectors respectively being attached to a voltage line and a ground line of a single phase two line type; and a power measurement circuit for multiplying a difference voltage between the voltage detected by the voltage line side clamp type detector and the voltage detected by the ground line side clamp type detector by the current detected by the voltage line side clamp type detector, to calculate the power.

Description

  The present invention relates to a power measurement device and a power measurement system, and more specifically, a power measurement device capable of measuring AC voltage, current, and power of a commercial power supply in a contactless manner with respect to a measurement target, and a plurality of powers The present invention relates to a power measurement system that acquires and processes a power value from a measurement device.

  In recent years, various research and development for practical application of smart grids have been conducted. Developments such as a supervisory control system for optimizing the supply and demand balance in the grid power network, power reception in ordinary households, control of power generation, and HEMS (Home Energy Management System) for power saving are being promoted. In such a system, it is necessary to accurately grasp the power consumption of the consumer, and a power measuring device called a smart meter is known. Unlike conventional analog watt-hour meters, smart meters are equipped with a digital measurement function and a communication function for transmitting measurement values to the monitoring control system and receiving control signals from the monitoring control system. It is a feature.

  There are a contact type and a non-contact type as a method of measuring voltage and current in the power measuring apparatus. A contact-type measuring device inserts a measuring device into the power line to be measured (conventional analog watt-hour meter), measures current and power, or branches from the power line (for example, from an outlet) Connect to a measuring device and measure the voltage. The non-contact type measuring device that can measure from the outside of the power line coating does not require any work on the power line and can be measured in the live line state. Widely used for As a non-contact type current measuring device, a clamp-type current detecting device including a magnetic core disposed so as to surround an outer periphery of a power line and a current detecting coil wound around the magnetic core is well known. . Moreover, although there are few examples, as a non-contact type voltage measuring device, a variable capacitance type (for example, see Patent Document 1), a resistance type (for example, see Patent Document 2) voltage measuring device, and the like are known.

  On the other hand, in configuring the power measuring device, it is necessary to separately provide the non-contact type current measuring device and the non-contact type voltage measuring device described above, which increases the size of the measuring device and complicates the measurement work. There was a problem that there was. Therefore, an integrated voltage / current measuring device as described in Patent Document 3 has been proposed.

Japanese Patent No. 5106816 JP 2012-177571 A Japanese Patent No. 4995663

  However, the clamp-type sensor described in Patent Document 3 is based on the premise that the voltage between the single-phase two-wire voltage line and the ground is measured, and the clamp-type sensor needs to be grounded for the measurement. . The power measuring device for grasping the power usage status is installed not only in large-scale consumers such as commercial facilities and factories, but also in ordinary households. Therefore, it is not preferable to require construction for the power line and grounding work for installation, as in conventional watt-hour meters and smart meters. In particular, when a power measuring device is retrofitted to an existing power distribution facility, it is desirable that a person who is not qualified for electrical work installs the power line without performing work on the power line and grounding work.

  In addition, since the stationary smart meter receives power supply from the grid power network, it requires electrical work for connecting the power lines. On the other hand, a portable measuring device such as a clamp-type sensor described in Patent Document 3 has a built-in battery as a power source. However, since a measuring device having a communication function such as a smart meter consumes a large amount of power, when a battery is used as a power source, battery replacement work frequently occurs.

  An object of the present invention is to provide a non-contact type power measuring device that is easy to attach to an existing power distribution facility, does not require a power supply facility that receives power supply from a system power network, and does not require grounding work. It is another object of the present invention to provide a power measurement system that acquires and processes power values from a plurality of power measurement devices.

  In order to achieve such an object, the first embodiment provides a magnetic core disposed so as to surround an outer periphery of a power line, a current detection coil wound around the magnetic core, and the magnetic In a power measuring device that detects the current and voltage of the power line by a clamp type detector having a voltage detection electrode attached to the inner periphery of the core and calculates the power, a single-phase two-wire voltage A voltage line to a differential voltage between two clamp type detectors attached to each of the line and the ground line, and a voltage detected by the clamp type detector of the voltage line and a voltage detected by the clamp type detector of the ground line. And a power measurement circuit for calculating power by multiplying the current detected by the clamp type detector.

  The power measurement device of the second embodiment includes a single-phase three-wire first-phase wire, three clamp-type detectors attached to the second-phase wire, and the neutral wire, and a first-phase-wire clamp-type The differential voltage between the voltage detected by the detector and the voltage detected by the neutral wire clamp type detector is multiplied by the current detected by the first phase line clamp type detector to obtain the first power. The differential voltage between the voltage detected by the neutral wire clamp type detector and the voltage detected by the second phase line clamp type detector is detected by the second phase line clamp type detector. And a power measurement circuit that calculates a second power by multiplying the current and calculates the power by adding the first and second powers.

  A power measurement device according to a third embodiment includes a magnetic core disposed so as to surround an outer periphery of a power line, a current detection coil wound around the magnetic core, and a voltage detection attached to the inner periphery of the magnetic core. In a power measuring device that detects the current and voltage of the power line by a clamp type detector including an electrode for calculating the power, a three-phase three-wire type or a three-phase four-wire first phase line, Three clamp-type detectors attached to each of the second and third phase wires, and the voltage detected by each clamp-type detector is multiplied by the current detected by each clamp-type detector to obtain power. And a power measuring circuit for calculation.

  As described above, according to the present invention, since the power measurement circuit is grounded to the neutral line via the electrostatic capacitance, it is not necessary to ground the power measurement device during measurement. Moreover, since the clamp type detector is used for the measurement of voltage and current, it is not necessary to perform grounding work even when it is attached to the existing power distribution equipment. Furthermore, since power is supplied from the power line via the clamp type detector, no power supply facility is required, and no electrical work for connecting the power line is required.

  In addition, since the power measuring device has a communication means to the outside, it can function as one sensor for remote sensing in the power measuring system.

It is a figure for demonstrating the measurement principle of the single phase two-wire system in the electric power measurement apparatus concerning the 1st Embodiment of this invention. It is a figure for demonstrating the measurement principle of the single-phase three-wire system in the electric power measurement apparatus concerning the 1st Embodiment of this invention. It is a figure for demonstrating the principle which measures a voltage. It is a figure which shows the structure of the electric power measurement apparatus concerning the 1st Embodiment of this invention. It is a figure for demonstrating the measurement method of the single phase two-wire system in an electric power measurement apparatus. It is a figure for demonstrating the measuring method of the single phase three-wire system in an electric power measuring apparatus. It is a figure which shows the time schedule in an electric power measurement apparatus. It is a figure which shows the structure of the electric power measurement system concerning the 1st Embodiment of this invention. It is a figure for demonstrating the measurement principle of the three-phase three-wire system (star-shaped connection) in the electric power measurement apparatus concerning the 2nd Embodiment of this invention. It is a figure for demonstrating the measurement principle of the three-phase four-wire system in the electric power measurement apparatus concerning the 3rd Embodiment of this invention. It is a figure for demonstrating the measurement principle of the three-phase three-wire system (delta connection) in the electric power measurement apparatus concerning the 4th Embodiment of this invention. It is a figure which shows the structure of the electric power measurement apparatus concerning the 5th Embodiment of this invention. It is a figure for demonstrating the voltage measurement method in the electric power measurement apparatus of 5th Embodiment. It is a figure which shows an example of the power fingerprint in 6th Embodiment.

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

(First embodiment)
With reference to FIG. 1, the measurement principle of the single-phase two-wire system in the power measuring device according to the first embodiment of the present invention will be described. And power is supplied to the load Z ₀ from the power source PS via the power distribution equipment of the single-phase two-wire. Clamp type detectors DET1 and DET2 for detecting voltage and current are disposed on the voltage line side and the ground line side of the power distribution facility. The clamp type detector includes an electrode for detecting a voltage and a coil for detecting a current, and each is connected to the power measurement circuit MES.

The power measurement circuit MES acquires the voltages v ₁ and I ₁ from the detector DET1, and acquires the voltages v ₂ and I ₂ from the detector DET2. The measured power P = V ₀ · I ₁ is
P = V ₀ · I ₁ = (v ₁ −v ₂ ) I ₁
As required. At this time, the leakage current IL = I ₁ −I ₂ can also be obtained simultaneously.

With reference to FIG. 2, the measurement principle of the single-phase three-wire system in the power measuring apparatus according to the first embodiment of the present invention will be described. Electric power is supplied from the power supply PS to the loads Z ₁ , Z ₂ , and Z ₃ through a single-phase three-wire distribution facility. Clamp-type detectors DET1, DET2, and DET3 for detecting voltage and current are disposed on the first phase line, the second phase line, and the neutral line of the power distribution facility. Power measurement circuit MES acquires a voltage _v 1, _{I 1} from the detector DET1, obtains the voltage _v 2, _{I 2} from the detector DET2, acquires the voltage _v n, _{I n} from the detector DET3. The power to be measured P = V ₁ · I ₁ + V ₂ · I ₂ is
P = V ₁ · I ₁ + V ₂ · I ₂ = (v ₁ −v _n ) I ₁ + (v _n −v ₂ ) I ₂
As required. In this case, it is possible to obtain the leakage current _{IL = I 1 -I 2 + I} n at the same time.

Here, the case where the variable capacitance type non-contact voltage measuring device described in Patent Document 1 is applied will be considered. With reference to FIG. 3, the principle of measuring the voltage in the power measurement circuit MES will be described. The variable capacitance circuit _Cv1 is connected to the electrode of the clamp type detector DET1, and is controlled by the control circuit CNT1. The control circuit CNT1 periodically changes the capacitance of the variable capacitance circuit _Cv1 , so that the voltage V _m1 of the first phase line and the reference voltage V _ref become equal, that is, the current _im1 becomes zero. Control (the same applies to the control circuit CNT2). At this time,
i _m1 = C (V ₁ − (V _m1 −V _m0 ))
i _m2 = C (V ₂ − (V _m2 −V _m0 ))
i _m1 + i _m2 = i _m0
When the control circuits CNT1 and CNT2 are controlled so that i _m1 = i _m2 = 0,
V ₁ − (V _m1 −V _m0 ) = 0, V ₂ − (V _m2 −V _m0 ) = 0
i _m1 + i _m2 = i _m0 = 0
Therefore, since V _m0 = V _ref = 0,
V ₁ = V _m1 , V ₂ = V _m2
Can be obtained. As shown in FIG. 3, since the neutral line is grounded in the system power network, by connecting the power measurement circuit MES to the neutral line, the neutral line is grounded via the capacitance, and the first phase The voltage of the line and the second phase line can be measured. Therefore, it is not necessary to ground the power measuring device at the time of measurement, and there is no need to perform a new grounding work when retrofitting to an existing distribution facility.

Even when the neutral line is not grounded in the system power network, the control circuit CNT3 (not shown) is connected to the clamp-type detector DET3, and the control is performed so that i _m1 = i _m2 = i _m0 = 0. If
V ₁ = V _m1 −V _m0 , V ₂ = V _m0 −V _m2
Can be obtained.

  FIG. 4 shows the configuration of the power measuring apparatus according to the first embodiment of the present invention. FIG. 4A is an external view of the entire apparatus. The power measuring device includes three clamp-type detectors 1a to 1c that can be attached to a three-wire power line, and a power measuring circuit 2 connected thereto.

  FIG. 4B shows the configuration of the clamp type detector of the power measuring device. The clamp type detector 1 is divided into two casings 1X and 1Y so that the power line can be clamped along the circumference. Each housing includes magnetic cores 11a and 11b disposed so as to surround the outer periphery of the power line, and a current detection coil wound around the magnetic core is connected to the terminals 13a and 13b. Electrodes 12 a and 12 b for voltage detection are attached to the inner circumferences of the magnetic cores 11 a and 11 b and connected to the terminal 14. When the magnetic cores 11a and 11b are conductors, the terminal 14 may be connected to either or both of the magnetic cores 11a and 11b instead of the electrodes for voltage detection.

  FIG. 4C shows the configuration of the power measurement circuit of the power measurement device. The power measurement circuit 2 calculates power from the voltage / current detection circuit 21 connected to each of the terminals 13a, 13b, and 14 of the three clamp-type detectors 1a-1c and the detection result of the voltage / current detection circuit 21. And a processing circuit 22. The processing circuit 22 includes a microcomputer, a DSP (Digital Signal Processor), an ASIC (Application Specific IC), and the like. The processing circuit 22 is connected to a memory 23 for storing the measured voltage, current, and power, and a communication circuit 24 for communicating with a server of the power measurement system.

  The communication circuit 24 can apply either wireless communication via the antenna 25, wired communication via the connector 26, or both. As will be described later, in order to communicate with the server, a user ID, a sensor ID, an address, and the like are assigned to each power measurement device and associated with the user and the installation location.

  The power supply circuit 31 is connected to the terminals 13a and 13b of the clamp type detector attached to either or both of the first phase line and the second phase line of the power line. The power supply circuit 31 takes out electric power from the current detection coil of the clamp type detector. The power supply control circuit 32 charges the storage battery 33 with the power from the power supply circuit 31 or the power from the external terminal 34, or supplies the power stored in the storage battery 33 to each circuit inside the power measurement circuit 2. The power supply circuit 31 can generate electric power from the terminal 14 of the clamp type detector, that is, the electrode for voltage detection, but the terminals 13a and 13b are more desirable from the viewpoint of efficiency.

  In this way, the power source of the power measuring device can be taken out from the power line in a non-contact manner, so that no electrical work is required for connecting the power source line when the power measuring device is attached.

  Further, by incorporating the storage battery 33, as will be described later, by repeating the measurement mode and the charging mode according to the time schedule, it is possible to operate autonomously without requiring external power supply. By shortening the interval of the measurement mode, it is possible to detect the disconnection of the power line, detect the leakage current, and notify the outside.

  FIG. 4D shows the configuration of the voltage / current detection circuit of the power measurement circuit. Current detection circuits 41a-41c are connected to the terminals 13a, 13b of the three clamp type detectors 1a-1c, and voltage detection circuits 42a-42c are connected to the terminals 14. The outputs of the current detection circuits 41a-41c are converted into digital signals by the A / D converters 44a-44c, respectively, and output to the processing circuit 22. The differential voltage between the clamp detector 1a for the first phase line and the clamp detector 1b for the neutral wire is calculated by the differential amplifier 43a, converted into a digital signal by the A / D converter 44d, and processed. 22 to output. The differential voltage between the second phase line clamp type detector 1c and the neutral line clamp type detector 1b is calculated by the differential amplifier 43b, converted into a digital signal by the A / D converter 44e, and processed by the processing circuit 22. Output to.

With reference to FIG. 5, a single-phase two-wire measurement method in the power measurement apparatus will be described. The processing circuit 22 includes (1) a current I ₁ on the voltage line side from the A / D converter 44a, (2) a current I ₂ on the ground line side from the A / D converter 44b, and (3) A / A A differential voltage (v ₁ −v ₂ ) between the voltage v ₁ on the voltage line side and the voltage v ₂ on the ground line side from the D converter 44 d is acquired.

The processing circuit 22 multiplies (1) and (3) to calculate power P = V ₀ · I ₁ = (v ₁ −v ₂ ) I ₁ , and subtracts (1) and (2). The leakage current IL = I ₁ −I ₂ is calculated. The processing circuit 22 stores the measured voltage, current, and power in the memory 23.

With reference to FIG. 6, a single-phase three-wire measurement method in the power measurement apparatus will be described. The processing circuit 22 includes (1) a current I ₁ on the first phase line side from the A / D converter 44a and (2) a voltage v ₁ on the first phase line side from the A / D converter 44d and neutrality. and it obtains the difference voltage between the voltage _{v n} line side _{(v 1 -v n), (} 3) by integrating both seek _{(v 1 -v n) I 1} . Next, the processing circuit 22 (4) the current I ₂ on the second phase line side from the A / D converter 44c and (5) the voltage v ₂ on the second phase line side from the A / D converter 44e. and it obtains the difference voltage _(v n -v ₂₎ of the voltage _{v n} neutral line side, (6) by integrating both seek _{(v n} -v 2) _{I 2.} (3) and (6) are added together to calculate electric power P = V ₁ · I ₁ + V ₂ · I ₂ = (v ₁ −v _n ) I ₁ + (v _n −v ₂ ) I ₂ .

Furthermore, (1) and (4), (7) and a current _{I n} of the neutral line side of the A / D converter 44b, and calculates the leakage current _{IL = I 1 -I 2 + I} n. The processing circuit 22 stores the measured voltage, current, and power in the memory 23.

  FIG. 7 shows an example of a time schedule in the power measuring apparatus. For example, as shown in FIG. 7A, the power measuring apparatus measures the power of the power line every 10 minutes and the processing circuit 22 stores it in the memory 23 (DET). While measurement is not being performed, the power supply control circuit 32 charges the storage battery 33 with power from the power line (POW). Also, as shown in FIG. 7B, the power measurement device transmits the measurement results stored at midnight and noon to the server of the power measurement system via the communication circuit 24.

  Such a time schedule can be defined in advance as a part of the program of the processing circuit 22. Alternatively, the processing circuit 22 may be activated in accordance with a time schedule by programming the power supply control circuit 32 in advance.

  As another example, the power measuring device can measure the power of the power line every minute, and the processing circuit 22 can store the integrated power in the memory 23. The power supply control circuit 32 may charge the storage battery 33 with power from the power line in parallel, and the power measurement device may transmit the measurement result to the server of the power measurement system at a fixed time.

  FIG. 8 shows the configuration of the power measurement system according to the first embodiment of the present invention. The power measuring apparatus 51 shown in FIG. 4A is installed in each home. In the power measuring apparatus shown in FIG. 4A, a relay power measuring apparatus 52 having a function of a relay station for multi-hop wireless communication is placed for each predetermined area, and further serves as a master station for these relay power measuring apparatuses. The relay power measuring device 53 is positioned for each predetermined area. For example, a 920 MHz band specific low power radio, a wireless LAN (Wi-Fi), or the like can be applied to the multi-hop wireless communication.

  The integrated relay power measurement device 53 is connected to the Internet network 55 via the wireless communication network 54 or the wired communication network 57 and can communicate with the server 56 of the power measurement system.

The server 56 of the power measurement system collects the measurement results of the power measurement devices installed in each home at regular times. The server 56 is, for example,
1) Aggregate the measurement results, grasp the power consumption trend for each specific range (post transformer, substation, region, etc.) and use it for demand forecasting.
2) Report to the maintenance department in response to detection of overcurrent and leakage.
3) Create data for billing according to the integrated power.
Functions such as can be implemented.

  According to the first embodiment, since the power measurement circuit is grounded to the neutral line via the capacitance, it is not necessary to ground the power measurement device during measurement. Moreover, since the clamp type detector is used for the measurement of voltage and current, it is not necessary to perform grounding work even when it is attached to the existing power distribution equipment. Furthermore, since power is supplied from the power line via the clamp-type detector, no electrical work is required for connecting the power line.

  Since the power measuring apparatus has a communication means to the outside, it can function as one sensor for remote sensing in the power measuring system. Further, by constantly measuring with the power measuring device, it is possible to detect an overcurrent and a leakage and control the circuit breaker. Further, a sensor that measures the temperature, humidity, atmospheric pressure, illuminance, and the like may be connected to the processing circuit 22 and transmitted to the server 56 together with a measurement result such as power. Information on these sensors is useful as a parameter for improving the accuracy of demand prediction described above.

(Second Embodiment)
In the first embodiment, a single-phase two-wire system or a single-phase three-wire system is taken as an example as a distribution system for a house in Japan. The present invention can be applied not only to a three-phase three-wire system (star connection), which is an industrial power distribution facility in Japan, but also to a three-phase three-wire system (delta connection) and a three-phase four-wire system. Hereinafter, it demonstrates in order.

With reference to FIG. 9, the measurement principle of the three-phase three-wire system (star connection) in the power measurement apparatus according to the second embodiment of the present invention will be described. In the case of a three-phase three-wire system (star connection), a clamp type detector and a control circuit are connected to each of the first, second, and third phase lines, and the reference potentials of the three control circuits are shared. To do. The variable capacitance circuits C _v1 -C _v3 are connected to the electrodes of the clamp type detectors DET1-DET3, respectively, and are controlled by the control circuits CNT1-CNT3. The control circuit CNT1 periodically changes the capacitance of the variable capacitance circuit _Cv1 so that the voltage V _m1 of the first phase line and the reference voltage V _N become equal, that is, the current i _m1 becomes zero. Control (the same applies to the control circuits CNT2 and CNT3). At this time,
i _m1 = C (V _G1 − (V _m1 −V _N ))
i _m2 = C (V _G2 − (V _m2 −V _N ))
i _m3 = C (V _G3 − (V _m3 −V _N ))
And V _G1 = V _G * exp (jθ): θ = 0,
V _G2 = V _G * exp (j2 / 3π)
V _G3 = V _G * exp (−j2 / 3π)
It becomes. Therefore, VG1 + VG2 + VG3 = 0.

Similarly, when V _m1 = V _m * exp (jθ): θ = 0,
V _m2 = V _m * exp (j2 / 3π)
V _m3 = V _m * exp (−j2 / 3π)
It becomes. These potentials are the floating potential, in the above formula plus a common reference potential V _N, V _N is one of the voltage values common to each expression. In such a case, it will be shown below that V _N becomes 0.

When the control circuits CNT1 to CNT3 are controlled so that i _m1 = i _m2 = i _m3 = 0,
V _G1 − (V _m1 −V _N ) = 0
V _G2 − (V _m2 −V _N ) = 0
V _G3 − (V _m3 −V _N ) = 0
Is obtained. Since i _m1 + i _m2 + i _m3 = 0,
V _G1 + V _G2 + V _G3 − (V _m1 + V _m2 + V _m3 ) + 3V _N = 0
Thus, V _m1 + V _m2 + V _m3 = 3V _N is obtained.

Therefore,
_{V m * exp (j0) +} V m * exp (j2 / 3π) + V m * exp (-j2 / 3π) = 0 = VN
It can be seen that V _N = 0. As described above, the control circuits CNT1 to CNT3 can acquire the phase voltages of the first phase line, the second phase line, and the third phase line. Even if one of the power lines is not grounded or the power measuring device is not grounded, the instantaneous voltage of the power line can always be measured accurately.

  Even in a three-phase three-wire system (star connection), which is an industrial power distribution facility in Japan, a clamp-type detector is a three-wire system using the power measurement device according to the first embodiment shown in FIG. Measurement results such as power can be obtained simply by attaching to the power line.

(Third embodiment)
With reference to FIG. 10, the measurement principle of the three-phase four-wire system in the power measuring device according to the third embodiment of the present invention will be described. The three-phase four-wire system is a configuration in which a grounded neutral wire is added to the three-phase three-wire system (star connection), and the first, second, and third phases are the same as in the second embodiment. A clamp type detector and a control circuit are connected to each of the lines, and the reference potentials of the three control circuits are made common.

The variable capacitance circuits C _v1 -C _v3 are connected to the electrodes of the clamp type detectors DET1-DET3, respectively, and are controlled by the control circuits CNT1-CNT3. The control circuit CNT1 periodically changes the capacitance of the variable capacitance circuit _Cv1 so that the voltage V _m1 of the first phase line and the reference voltage V _N become equal, that is, the current i _m1 becomes zero. Control (the same applies to the control circuits CNT2 and CNT3). Since the neutral point of the first to third phase lines and the reference potentials of the three control circuits are fixed to V _GN = V _N = 0, the control circuits CNT 1 to CNT 3 are the same as in the second embodiment. Each phase voltage of the -3 phase line can be acquired.

  As a result, power can be calculated from the measured phase voltage and the phase current detected by the current detection circuit. As in the case of the single-phase three-wire system of the first embodiment, a leakage current can also be measured by attaching a clamp type detector to the neutral wire and connecting it to a current detection circuit and a voltage detection circuit. it can.

(Fourth embodiment)
With reference to FIG. 11, the measurement principle of the three-phase three-wire system (delta connection) in the power measuring device according to the fourth embodiment of the present invention will be described. Also in the case of delta connection, a clamp type detector and a control circuit are connected to each of the first, second, and third phase lines, and the reference potentials of the three control circuits are made common. The variable capacitance circuits C _v1 -C _v3 are connected to the electrodes of the clamp type detectors DET1-DET3, respectively, and are controlled by the control circuits CNT1-CNT3. The control circuit CNT1 periodically changes the capacitance of the variable capacitance circuit _Cv1 so that the voltage V _m1 of the first phase line and the reference voltage V _N become equal, that is, the current i _m1 becomes zero. Control (the same applies to the control circuits CNT2 and CNT3).

  In the case of the delta connection, since there is no point corresponding to the neutral point of the star connection, one of the first to third phase lines is grounded (in FIG. 11, the second phase line is grounded). According to this configuration, the control circuit CNT1 can acquire the line voltage between the first phase line and the second phase line (neutral line), that is, the phase voltage of the first phase line. In the control circuit CNT3, The line voltage between the third phase line and the second phase line (neutral line), that is, the phase voltage of the third phase line can be acquired. This is the same as in the case of the single-phase three-wire system of the first embodiment (see FIG. 3).

  According to the first to fourth embodiments, the power measuring device shown in FIG. 4 can be used for any connection system regardless of whether in Japan, overseas, residential use, industrial use, etc. Etc. can be obtained.

(Fifth embodiment)
FIG. 12 shows a configuration of a power measuring apparatus according to the fifth embodiment of the present invention. FIG. 5A is an external view of the entire apparatus. The power measuring apparatus includes three clamp-type detectors 101a to 101c that can be attached to a three-wire power line, and a power measuring circuit 102 connected thereto.

  FIG. 12B shows the configuration of the clamp type detector of the power measuring device. The clamp type detector 101 is divided into two casings 101X and 101Y so that the power line can be clamped along the circumference. Each housing includes magnetic cores 111a and 111b disposed so as to surround the outer periphery of the power line, and a current detection coil wound around the magnetic core is connected to the terminals 113a and 113b. Unlike the power measurement device of the first embodiment, no electrode for voltage detection is provided.

  FIG. 12C shows the configuration of the power measurement circuit of the power measurement device. The power measurement circuit 102 includes a voltage / current detection circuit 121 connected to each of the terminals 113a and 113b of the three clamp-type detectors 101a to 101c, and a processing circuit that calculates power from the detection result of the voltage / current detection circuit 121. 122. The processing circuit 122 is connected to a memory 123 that stores the measured voltage, current, and power, and a communication circuit 124 that communicates with a server of the power measurement system.

  The communication circuit 124 can apply either wireless communication via the antenna 125, wired communication via the connector 126, or both. A power supply circuit 131 is connected to the terminals 113a and 113b of the clamp-type detector attached to either or both of the first phase line and the second phase line of the power line. The power supply circuit 131 takes out electric power from the current detection coil of the clamp type detector. The power supply control circuit 132 charges the storage battery 133 with the power from the power supply circuit 131 or the power from the external terminal 134, and supplies the power stored in the storage battery 133 to each circuit inside the power measurement circuit 102.

  FIG. 12D shows the configuration of the voltage / current detection circuit of the power measurement circuit. Current detection circuits 141a-141c and voltage detection circuits 142a-142c are connected to terminals 113a, 113b of the three clamp type detectors 101a-101c, respectively. Outputs of the current detection circuits 141a to 141c are converted into digital signals by the A / D converters 144a to 144c, respectively, and output to the processing circuit 122. A differential voltage between the first phase line clamp type detector 101a and the neutral line clamp type detector 101b is calculated by the differential amplifier 143a, converted into a digital signal by the A / D converter 144d, and processed. It outputs to 122. The differential voltage between the second phase line clamp type detector 101c and the neutral line clamp type detector 101b is calculated by the differential amplifier 143b, converted into a digital signal by the A / D converter 144e, and processed by the processing circuit 122. Output to.

With reference to FIG. 13, a voltage measurement method in the power measurement apparatus of the fifth embodiment will be described. A voltage e ₁ proportional to the current I ₁ flowing through the electric wire W is generated at both ends ac of the coil DET for detecting the current. The voltage detection circuit includes a variable capacitance element C ₁ connected to one terminal a of the coil DET and a control circuit CNT connected to the other terminal of the variable capacitance element C ₁ .

The voltage detection circuit connected to the terminal a of the coil DET, the capacitance _{C 0} between the wire W- coils DET, current flows _{i m1} through a variable capacitance element _{C 1.}

Here, the control circuit CNT periodically changes the capacitance of the variable capacitance circuit C ₁ so that the voltage of the electric wire W, that is, the voltage V _m1 of the terminal a of the coil DET and the voltage of the terminal b are equal. That is, the current _im1 is controlled to be zero. That is, V ₀ is set as the reference potential of the control circuit CNT, and the voltage V _ref applied from the control circuit CNT to the terminal b is adjusted so that the current _{im 1} becomes zero. At this time, a ground potential indicated by the voltmeter VM is equal to V _1.

i _m1 = 0, V ₁ − (V _ref + V ₀ ) = 0
That is, V ₁ = V _m1 = V _ref + V ₀ .

In the single-phase two-wire voltage measurement method, the differential voltage (v ₁ −v ₂ ) between the voltage V ₁ on the voltage line side and the voltage V ₂ on the ground line side is calculated in the same manner as shown in FIG. That's fine. That is, the voltage detection circuit adjusts the voltages V _ref1 and V _ref2 so that the currents i _m1 and i _m2 become zero.

V _ref1 = V ₁ −V ₀ , V _ref2 = V ₂ −V ₀
Since the voltage of the ground wire is V ₂ = 0,
V _ref1 −V _ref2 = (V ₁ −V ₀ ) − (V ₂ −V ₀ ) = V ₁
Can be obtained. The voltage between the first phase line-neutral line and the second phase line-neutral line of the single-phase three-wire system can be obtained in the same manner.

In addition, the voltage between the first phase line and the second phase line of the single-phase three-wire system, the three-phase three-wire line voltage,
V _ref1 −V _ref2 = (V ₁ −V ₀ ) − (V ₂ −V ₀ ) = V ₁ −V ₂
Can be obtained as

A shunt resistor may be used as a current detection method in the current detection circuit. In this case, a shunt resistor is connected between the terminals ac of the coil DET. At this time, the induced current circulates between the coil DET and the shunt resistor, and thus does not affect the current I ₁ for voltage detection.

  According to the fifth embodiment, the clamp type detector includes only the magnetic core and the current detection coil, and the connection line between the electrode, the terminal, and the power measurement circuit for voltage detection can be omitted. it can. Needless to say, the configuration of the power measurement apparatus of the fifth embodiment can be applied to the power measurement apparatus of the first to fourth embodiments.

(Sixth embodiment)
A method in which the power measurement system performs power fingerprint authentication using the power measurement devices according to the first to fifth embodiments will be described. A power fingerprint is identification information for identifying a power device. A characteristic waveform of power consumption peculiar to an electric device is derived from a time-series change in power, voltage or current consumed by the electric device during operation. Extracted. There are various types of electrical equipment connected to power distribution facilities in consumers, and various modes of power consumption. For example, on a macro basis, the power consumption waveform varies depending on the load, such as a device that can be regarded as a resistive load such as an incandescent lamp or a heating wire, a device that includes an electric motor or an inverter, or a device that performs periodic operation. Further, microscopically, the voltage waveform, current waveform, and phase relationship between AC cycles from the grid power network differ depending on the load.

  Therefore, a macroscopic power consumption waveform, a microscopic voltage waveform and a current waveform are measured in advance for each electrical device and stored as a power fingerprint in the server 56 of the power measurement system shown in FIG. deep. The server 56 collects the measurement results of the power measurement devices installed in each home and compares them with the power fingerprint, thereby making it possible to grasp the power consumption tendency for each home in more detail.

  The server 56 collects measurement results such as the power of the power line measured by a power measurement device at a predetermined time interval (for example, about 1 second to about 1 minute) from a certain household for a predetermined time (for example, 60 minutes). To do. For example, as shown in FIG. 14A, when the amount of power consumed changes at a constant time interval and the same pattern is repeated, the server 56 stores a macro-like power consumption waveform stored in advance. Compared with, identify the electrical equipment used. When a plurality of electric devices are used at the same time, the plurality of electric devices are specified by superimposing and comparing power fingerprints of the plurality of electric devices assumed.

  In addition, the processing circuit 22 of the power measuring device measures the power of the power line and the like in a memory 23 at a predetermined time interval (for example, 0.01 ms) for a predetermined time (for example, 10 ms for 50 Hz AC half cycle). Store it. For example, as shown in FIG. 14B, a voltage waveform and a current waveform for one AC cycle are created. The processing circuit 22 transmits a voltage waveform and a current waveform created every predetermined time (for example, 1 second) to the server 56, and the server 56 is used in comparison with the power fingerprint stored in advance. Identify the electrical equipment.

  According to the power measuring apparatus according to the first to fifth embodiments, it is possible to easily measure a macro power consumption waveform, a micro voltage waveform, and a current waveform. It is possible to grasp the power consumption trend in more detail.

DESCRIPTION OF SYMBOLS 1,100 Clamp type detector 2,200 Electric power measurement circuit 11, 211 Magnetic core 12 Electrode 13, 14, 213, 214 Terminal

Claims (14)

Clamp-type detection comprising a magnetic core arranged to surround the outer periphery of the power line, a current detection coil wound around the magnetic core, and an electrode for voltage detection attached to the inner periphery of the magnetic core In a power measuring device that detects the current and voltage of the power line by means of a device and calculates power,
Two clamp-type detectors attached to each of a single-phase two-wire voltage line and a ground line;
The difference voltage between the voltage detected by the voltage line clamp type detector and the voltage detected by the ground line clamp type detector is multiplied by the current detected by the voltage line clamp type detector to A power measuring device comprising: a power measuring circuit for calculating.   The power measurement circuit calculates a leakage current from a difference between a current detected by a clamp type detector of a voltage line and a current detected by a clamp type detector of a ground line. Power measuring device.   The power measuring apparatus according to claim 1, further comprising a power supply circuit that extracts power from a current detection coil of a clamp detector of a voltage line. Clamp-type detection comprising a magnetic core arranged to surround the outer periphery of the power line, a current detection coil wound around the magnetic core, and an electrode for voltage detection attached to the inner periphery of the magnetic core In a power measuring device that detects the current and voltage of the power line by means of a device and calculates power,
Three clamp-type detectors attached to each of the first phase wire, the second phase wire and the neutral wire of the single-phase three-wire system;
The differential voltage between the voltage detected by the clamp detector of the first phase line and the voltage detected by the clamp detector of the neutral wire is multiplied by the current detected by the clamp detector of the first phase wire. Then, the first power is calculated, and the second phase line is clamped to the differential voltage between the voltage detected by the neutral line clamp type detector and the voltage detected by the second phase line clamp type detector. A power measurement circuit comprising: a power measurement circuit that calculates a second power by multiplying a current detected by a type detector, and calculates the power by adding the first and second powers apparatus.   The power measurement circuit detects the difference between the current detected by the first phase line clamp type detector and the current detected by the second phase line clamp type detector by the neutral line clamp type detector. The power measurement device according to claim 4, wherein the leakage current is calculated by adding the measured currents.   6. The power measurement according to claim 4, further comprising a power supply circuit that extracts power from a current detection coil of the clamp detector of the first phase line and / or the clamp detector of the second phase line. apparatus. Clamp-type detection comprising a magnetic core arranged to surround the outer periphery of the power line, a current detection coil wound around the magnetic core, and an electrode for voltage detection attached to the inner periphery of the magnetic core In a power measuring device that detects the current and voltage of the power line by means of a device and calculates power,
Three clamp-type detectors attached to each of the first phase line, the second and third phase lines of the three-phase three-wire type or the three-phase four-wire type;
A power measurement device comprising: a power measurement circuit that calculates power by multiplying a voltage detected by each clamp type detector by a current detected by each clamp type detector.   The power measuring circuit calculates a leakage current from a difference between a current detected by each clamp type detector and a current detected by a neutral type clamp type detector. The power measuring device described.   The power measuring device according to claim 7 or 8, further comprising a power supply circuit that extracts power from a current detection coil of at least one clamp type detector. The power measurement circuit includes:
An A / D converter for converting the detected current and the detected voltage into a digital signal;
A processing circuit for calculating power from the current and voltage converted into a digital signal;
A memory for storing the measured voltage, current, and power;
The power measurement device according to claim 1, further comprising: a communication circuit that transmits the measured voltage, current, and power values. A plurality of power measuring devices according to claim 10;
And a server for receiving the measured voltage, current, and power values from each of the power measuring devices.   The server stores time-series changes in power consumed during operation of the electric device as voltage, current, and power waveforms, and stores waveforms obtained from the measured voltage, current, and power as stored waveforms. The electric power measurement system according to claim 11, wherein the electric device is specified by comparison.   The power measurement system according to claim 11 or 12, wherein the plurality of power measurement devices include a communication circuit capable of multi-hop wireless communication. In a power measurement device that calculates a current of the power line by a clamp type detector including a magnetic core disposed so as to surround an outer periphery of the power line and a current detection coil wound around the magnetic core.
A variable capacitance element having one terminal connected to one end of the current detection coil;
A control circuit connected to the other terminal of the variable capacitance element,
By adjusting the current flowing through the variable capacitance element to be zero, the ground voltage of the other terminal of the variable capacitance element is detected by the current detection coil so as to be equal to the ground voltage of the power line. And a power measuring circuit for calculating power by multiplying the ground current by the ground voltage.