JP2016095266A - Device, system, method, and program for measuring current - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable correction of minute current measured by a usual current sensor for an effect of electromagnetic induction by large current flowing through an adjacent current path.SOLUTION: A current measurement device is connected to current sensors for measuring current flowing through respective current paths, and includes correction means configured to correct a value of current for a first current path to zero when the value of current for the first current path is less than a first threshold value and a value of current for a second current path adjacent to the first current path is greater than a second threshold value that is greater than the first threshold value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a current measurement device, a current measurement system, a current measurement method, and a current measurement program that measure current with high accuracy.

  In recent years, power measurement has been performed using a clamp-type current sensor to measure the AC power of a plurality of branch wire paths (hereinafter referred to as “branch circuit”. Also referred to as “electric circuit”) in a distribution board. Equipment may be used. In the power measuring apparatus, it is required to measure the power consumption for each branch electric circuit with high accuracy.

  An example of a technique for measuring the power consumption of each branch circuit in the distribution board with high accuracy is disclosed in Patent Document 1.

  The distribution board of Patent Document 1 includes a current sensor unit that includes a current sensor that detects a current flowing through each branch circuit, and a communication measurement unit that calculates power consumption for each branch circuit. The current sensor unit stores, as a correction value, the ratio of the current detected by the current sensor to the reference current passed through each branch circuit, measured before factory shipment. The communication measurement unit corrects the measurement value for each branch circuit based on the correction value stored in advance in the current sensor unit, and calculates the power consumption for each branch circuit based on the correction value.

  As a result of the above operation, when the current sensor unit is replaced, the distribution board of Patent Document 1 measures the power consumption with high accuracy without adjusting the error for each current sensor after the replacement.

  Another example of a technique for measuring the power consumption of each branch circuit in the distribution board with high accuracy is disclosed in Patent Document 2.

  The distribution board of Patent Document 2 includes a sensor unit and a measurement unit. The sensor unit detects the voltage and current of the main trunk that is supplied with external power and the current of each branch circuit that branches and outputs the power supplied to the main trunk. The measurement unit first calculates the total amount of power supplied from the main trunk to the branch circuit based on the detection results of the main trunk voltage and current. Next, the measurement unit calculates a current distribution ratio indicating the ratio of the current for each branch electric circuit to the total amount of current flowing through the plurality of branch lines based on the detection result of the current flowing through each branch electric line. Subsequently, the measurement unit calculates the electric energy for each branch electric circuit based on the total electric energy and the current distribution ratio.

  As a result of the above operation, the distribution board of Patent Document 2 calculates the total amount of power in consideration of the phase difference between the main trunk voltage and current. That is, the total amount of power calculated by the distribution board has a smaller error than the amount of power calculated using the rated voltage with the power factor fixed at 1. Therefore, the distribution board of patent document 2 measures the electric energy for every branch electric circuit branched from the main trunk road with high precision.

  In general, in a power measuring apparatus, when a plurality of branch circuits are wired in parallel in the distribution board, if there is a branch circuit where a large current flows, a magnetic field is generated in another adjacent branch circuit. Leakage current occurs due to the influence.

  In the power measuring device, it is desirable to measure the power consumption of each branch circuit with high accuracy by removing the influence of the magnetic field from another adjacent branch circuit.

  An example of a current sensor technique that is not easily influenced by an external magnetic field is disclosed in Patent Document 3.

  The current sensor of Patent Document 3 includes a magnetic core through which a current bar passes, a current detection coil wound around the magnetic core, and a compensation coil installed in the vicinity of the magnetic core. The compensation coil cancels an error voltage generated in the current detection coil by the external magnetic field.

  As a result of the above operation, the current sensor disclosed in Patent Document 3 is not easily affected by the external magnetic field and accurately measures the current.

JP 2014-193102 A JP2014-096923A JP2008-101914A

  The distribution board of Patent Document 1 and the distribution board of Patent Document 2 have a problem that a minute current affected by electromagnetic induction due to a large current flowing in an adjacent branch circuit cannot be corrected.

On the other hand, the current sensor of Patent Document 3 has a problem that the cost of the current sensor increases because it has a compensation coil.
(Object of invention)
A main object of the present invention is to provide a current measuring device and a current measuring system capable of correcting a minute current affected by electromagnetic induction due to a large current flowing in an adjacent electric circuit in a minute current measured using a normal current sensor. And providing a current measurement method and a current measurement program.

  The current measuring device according to the present invention is a current measuring device connected to a current sensor for measuring a current flowing through each electric circuit, wherein the current value of the first electric circuit is smaller than the first threshold value, and the first And a correction unit that corrects the current value of the first electric circuit to zero when the current value of the second electric circuit adjacent to the electric circuit is larger than the second threshold value that is larger than the first threshold value. Features.

  A current measurement system according to the present invention includes a distribution board including a main trunk that receives external power and a plurality of electric circuits branched from the main trunk, a current sensor that measures a current flowing through each electric circuit, and a first electric circuit. Is smaller than the first threshold value and the current value of the second electric circuit adjacent to the first electric circuit is larger than the second threshold value larger than the first threshold value, And a current measuring device including correction means for correcting the current value of one electric circuit to zero.

  In the current measurement method of the present invention, in a current measurement device connected to a current sensor that measures a current flowing through each electric circuit, the current value of the first electric circuit is smaller than the first threshold value, and the first electric circuit The current value of the first electric circuit is corrected to zero when the current value of the adjacent second electric circuit is larger than the second threshold value that is larger than the first threshold value.

  The current measurement program of the present invention is a current measurement device connected to a current sensor that measures a current flowing through each electric circuit, wherein the current value of the first electric circuit is smaller than the first threshold value and the first When the current value of the second electric circuit adjacent to the electric circuit is larger than the second threshold value that is larger than the first threshold value, the computer executes a correction process for correcting the current value of the first electric circuit to zero. It is characterized by making it.

  According to the present invention, there is an effect that in a minute current measured using a normal current sensor, a minute current affected by electromagnetic induction due to a large current flowing in an adjacent electric circuit can be corrected.

It is a block diagram showing an example of composition of current measuring device 100 in a 1st embodiment of the present invention. It is a flowchart which shows operation | movement of the electric current measurement apparatus 100 in the 1st Embodiment of this invention. It is a figure for demonstrating the specific example of the operating conditions of the electric current measurement apparatus 100 in the 1st Embodiment of this invention. It is a figure for demonstrating the specific example of operation | movement of the electric current measurement apparatus 100 in the 1st Embodiment of this invention. It is a block diagram which shows an example of a structure of the current measurement apparatus 110 in the 2nd Embodiment of this invention. It is a block diagram which shows an example of a data structure of the current measurement apparatus 110 in the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the electric current measurement apparatus 110 in the 2nd Embodiment of this invention. It is a block diagram which shows an example of a data structure of the current measurement apparatus 130 in the 3rd Embodiment of this invention. It is a figure for demonstrating the structure of the electricity distribution panel 300 in the 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, equivalent components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
(First embodiment)
A configuration in the present embodiment will be described.

  FIG. 1 is a block diagram showing an example of the configuration of the current measuring apparatus 100 according to the first embodiment of the present invention. The current measuring device 100 is connected to a current sensor 201 and a current sensor 202.

  The current sensor 201 and the current sensor 202 detect currents flowing through the electric circuit 301 (electric circuit A) and the electric circuit 302 (electric circuit B), respectively. The current sensor 201 and the current sensor 202 are, for example, clamped AC current sensors. The current sensor 201 and the current sensor 202 do not need to have a compensation coil or the like for canceling an error voltage generated by an external magnetic field.

  The current measuring apparatus 100 includes a measured current holding unit 102 and an induced current correcting unit 101.

  The measurement current holding unit 102 holds the current value for each electric circuit measured by the current sensor 201 and the current sensor 202.

  In the following, a current having a magnitude that may generate a minute current having a magnitude that cannot be ignored by a magnetic field in an “adjacent” circuit is referred to as a “large current”. “Proximity” between electric circuits means that the current value generated in another electric circuit due to electromagnetic induction generated by a large current flowing in the electric circuit is a distance that is an error that cannot be ignored for the other electric circuit. Whether or not a certain current is a large current is determined by whether or not the magnitude of the current is equal to or greater than a “large current threshold”.

  In the following, a current having a magnitude that may cause an error of a magnitude that cannot be ignored due to the influence of a magnetic field caused by a large current flowing in an adjacent circuit is called a “small current”. . Whether or not a certain current is a small current is determined by whether or not the magnitude of the current is equal to or smaller than a “small current threshold”.

  The induced current correction unit 101 holds in advance the large current threshold and the small current threshold and the “proximity relationship” between the electric circuits. The “proximity relationship” between each electric circuit is information indicating whether any two electric circuits are close to each other. The induced current correction means 101 is based on the large current flowing through the adjacent electric circuit that is a small current in the current value for each electric circuit measured by the current sensor based on the large current threshold, the small current threshold, and the proximity relationship. The current value that caused an error that cannot be ignored due to the magnetic field is corrected. Specifically, the induced current correction means 101 corrects the current value of a circuit that is a small current and a large current flows through an adjacent circuit to zero.

  Next, the operation in this embodiment will be described.

  FIG. 2 is a flowchart showing the operation of the current measuring apparatus 100 according to the first embodiment of the present invention. FIG. 2 shows the operation of the current measuring apparatus 100 when processing one current value detected by one current sensor. Further, the flowchart shown in FIG. 2 and the following description are examples, and the processing order and the like may be changed, the processing may be returned, or the processing may be repeated according to the processing that is appropriately obtained.

  The induced current correcting means 101 of the current measuring apparatus 100 determines whether or not the current value measured by the current sensor and held by the measured current holding means 102 is less than or equal to the small current threshold for a specific electric circuit (step S101). ). If the current value held by the measured current holding means 102 is not less than or equal to the small current threshold (step S101: No), the induced current correcting means 101 ends the process. If the current value held by the measured current holding unit 102 is equal to or smaller than the small current threshold (step S101: Yes), the induced current correcting unit 101 proceeds to the process of step S102.

  The induced current correcting unit 101 of the current measuring apparatus 100 has another electric circuit that is close to the specific electric circuit, which is measured by the current sensor and the current value held by the measured current holding unit 102 is equal to or larger than the large current threshold. Whether or not (step S102). If there is no other electric circuit (step S102: No), the induced current correction unit 101 ends the process. If another electric circuit exists (step S102: Yes), the induced current correction unit 101 corrects the current value measured by the current sensor to zero for the specific electric circuit (step S103).

  Next, a specific example of processing according to the first embodiment of this invention will be described.

  FIG. 3 is a diagram for explaining a specific example of operating conditions of the current measuring apparatus 100 according to the first embodiment of the present invention. The current measuring device 100 measures the currents of the four electric circuits. Specifically, the current sensor 201, the current sensor 202, the current sensor 203, and the current sensor 204 are the electric circuit 301 (electric circuit A), the electric circuit 302 (electric circuit B), the electric circuit 303 (electric circuit C), and the electric circuit 304 (electric circuit D), respectively. ) Is detected.

  FIG. 4 is a diagram for explaining a specific example of the operation of the current measuring apparatus 100 according to the first embodiment of the present invention. 4A shows the proximity relationship between the electric circuit A, the electric circuit B, the electric circuit C, and the electric circuit D held by the induced current correction unit 101 of the current measuring device 100. FIG. In FIG. 4A, the electric circuits are arranged in the order of electric circuit A, electric circuit B, electric circuit C, and electric circuit D, and adjacent electric circuits are close to each other. FIG. 4B shows the large current threshold and the small current threshold held by the induced current correction unit 101 of the current measuring apparatus 100. In FIG. 4B, the large current threshold is “10 A” and the small current threshold is “0.5 A”. The small current threshold is, for example, an intermediate current value between the standby current of the load connected to each electric circuit and the current during operation. The values of the standby current and the current during operation are determined based on load specifications or experiments. The large current threshold is, for example, a current value of one circuit that causes a current of one circuit to generate a predetermined ratio of an induced current to a small current of the other circuit when the circuits are separated by a certain average distance. As determined. The magnitude of the induced current is determined based on electric circuit specifications or experiments. FIG. 4C shows the measured current for each electric circuit held by the measured current holding means 102 of the current measuring device 100. In FIG. 4C, the measured current of the electric circuit A is “0.2 A”, the measured current of the electric circuit B is “20 A”, the measured current of the electric circuit C is “1 A”, and the measured current of the electric circuit D is “0.1 A”. It is. FIG. 4D shows the current value for each electric circuit corrected by the induced current correcting unit 101 of the current measuring device 100.

  First, the electric circuit A will be described. The induced current correcting means 101 of the current measuring apparatus 100 has the measured current of the electric circuit A being “0.2 A” and is not more than the small current threshold value “0.5 A” (step S101: Yes), so the process proceeds to step S102. move on. The induced current correcting unit 101 corrects the current value measured by the current sensor to zero because there is an adjacent electric circuit B having a current value equal to or greater than the large current threshold “10A” for the electric circuit A (step S102: Yes). (Step S103).

  Next, the electric circuit B will be described. The induced current correcting means 101 of the current measuring apparatus 100 ends the process because the measured current of the electric circuit B is “20 A” and is not less than the small current threshold “0.5 A” (step S101: No).

  Next, the electric circuit C will be described. The induced current correcting unit 101 of the current measuring apparatus 100 ends the process because the measured current of the electric circuit C is “1A” and is not less than the small current threshold value “0.5 A” (step S101: No).

  Subsequently, the electric circuit D will be described. The induced current correcting means 101 of the current measuring apparatus 100 has the measured current of the electric circuit D being “0.1 A” and is not more than the small current threshold value “0.5 A” (step S101: Yes), so the process proceeds to step S102. move on. The induced current correction unit 101 ends the process for the electric circuit D because there is no adjacent electric circuit having a current value equal to or greater than the large current threshold “10A” (step S102: No).

  As a result of the above operation, the current value for each electric circuit is corrected as shown in FIG. That is, the current value of the electric circuit A is corrected from “0.2 A” to “0 A”, and the electric current values of the electric circuit B, the electric circuit C, and the electric circuit D are not corrected.

As described above, the current measuring apparatus 100 according to the present embodiment is a small current that is greatly influenced by the current flowing through the adjacent electric circuit, and the large current flows through the adjacent electric circuit. The current value of the electric circuit that is greatly affected by is corrected to zero. On the other hand, the current measuring apparatus 100 does not correct the current value of the electric circuit in which the current flowing through the adjacent electric circuit is small and the current larger than the small current flows. In addition, the current measuring device 100 does not correct the current value regardless of the magnitude of the current flowing through the electric circuit because the influence of electromagnetic induction from the adjacent electric circuit is small for the electric circuit in which a large current does not flow through the adjacent electric circuit. . Therefore, the current measuring apparatus 100 can correct only a minute current that is affected by electromagnetic induction due to a large current flowing in an adjacent electric circuit in a minute current measured using a normal current sensor.
(Second Embodiment)
Next, in the first embodiment described above, a second embodiment of the present invention will be described in which a correction value of a current flowing through each electric circuit is displayed on an external monitor device. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  A configuration in the present embodiment will be described.

  FIG. 5 is a block diagram showing an example of the configuration of the current measuring device 110 according to the second embodiment of the present invention. The current measuring device 110 is connected to the alternating current sensors 308, 309, 310 and the like installed in the distribution board 300 and the monitor device 400.

  The monitor device 400 displays current data measured by the current measurement device 110 on the screen by communicating with the current measurement device 110 through a specific low-power radio or the like. The user can check the current consumption of the loads 311, 312, 313 and the like supplied with power from the distribution board 300 via the monitor device 400.

  The distribution board 300 includes a main circuit breaker 304 connected to the main AC circuit, branch breakers 305, 306, 307 connected to the main circuit breaker 304, and the like. The electric circuit “L1” and the electric circuit “L2” indicate an electric circuit to which an alternating current of 100 volts is supplied, and the electric circuit “N” indicates a neutral line. The branch breakers 305, 306, 307, etc. are connected to loads 311, 312, 313, etc. via branch electric circuits 317, 318, 319, etc., respectively.

  The alternating current sensors 308, 309, 310, etc. connected to the current measuring device 110 detect the currents flowing through the branch electric circuits 317, 318, 319, etc., respectively. The alternating current sensors 308, 309, 310, etc. output the detected current as a voltage signal. The alternating current sensors 308, 309, 310, etc. are, for example, clamped alternating current sensors. The alternating current sensors 308, 309, 310 and the like do not need to have a compensation coil or the like for canceling an error voltage generated by an external magnetic field.

  The current measurement device 110 includes an AD (Analog to Digital) conversion unit 115, a memory 116, and a CPU (Central_Processing_Unit) 114.

  The AD conversion unit 115 receives the voltage signal output from the AC current sensors 308, 309, 310, etc., converts the analog value into a digital value, and outputs the digital value.

  The memory 116 stores data relating to the measured current converted into a digital value.

  The CPU 114 controls processing in the current measuring device 110. Note that the CPU 114 may include an AD conversion unit 115 and a memory 116.

  FIG. 6 is a block diagram showing an example of the data configuration of the current measuring device 110 according to the second embodiment of the present invention. The memory 116 includes a data area 120 that is an area for storing current measurement data, current correction data, “large current flag”, and “small current flag” information for each branch circuit. The “large current flag” is information indicating whether or not the measured current of a specific electric circuit is a large current. The “small current flag” is information indicating whether or not the measured current of a specific electric circuit is a small current. The memory 116 includes a parameter area 121 that is an area for storing information on a large current threshold and a small current threshold.

  For example, the case where the alternating current sensors 308, 309, 310, etc. are clamped alternating current sensors and power is consumed in the load 312 will be described.

  The current supplied from the main AC circuit flows to the branch breaker 306 and the branch circuit 318 via the main circuit breaker 304.

  The magnetic field generated in the branch circuit 318 generates an output current (secondary current) in the secondary winding wound around the inner core of the AC current sensor 309. The secondary current is converted into a voltage signal by flowing through the load resistance. As a result, the alternating current sensor 309 outputs a voltage signal indicating the current flowing through the branch circuit 318 to the current measuring device 110.

  The AD conversion means 115 converts the input voltage signal from an analog value to a digital value and stores it in the measurement data B in the data area 120 of the memory 116.

  On the other hand, the magnetic field generated in the branch circuit 318 generates a minute secondary current also in the secondary windings of the adjacent AC current sensor 308 and AC current sensor 310. The minute secondary current is converted into a voltage signal by flowing through the load resistance. As a result, the alternating current sensor 308 and the alternating current sensor 310 output a voltage signal indicating an error caused by the current flowing through the branch circuit 318 to the current measuring device 110.

  The AD conversion means 115 converts the input voltage signal from an analog value to a digital value and stores it in “measurement data A” and “measurement data C” in the data area 120 of the memory 116.

  In this case, “measurement data A” and “measurement data C” are not current values flowing through the branch circuit 317 and branch circuit 319, but current values generated by electromagnetic induction from the adjacent branch circuit 318. is there. That is, the current values stored in “measurement data A” and “measurement data C” are erroneous current values that are generated even though the load 311 and the load 313 do not consume power.

  Next, the operation in this embodiment will be described.

  FIG. 7 is a flowchart showing the operation of the current measuring device 110 according to the second embodiment of the present invention. FIG. 7 shows the operation of the current measuring device 110 when processing one current value detected by one AC current sensor. Further, the flowchart shown in FIG. 7 and the following description are examples, and the processing order and the like may be changed, the processing may be returned, or the processing may be repeated depending on the processing that is appropriately obtained.

  Prior to the processing, the value of the large current flag of the branch circuit selected as the processing target is deleted in advance.

  In the following processing, it is assumed that processing is performed in order from the branch electric circuit with the largest measurement data value. When the current measurement interval is sufficiently smaller than the time constant of the current change, when executing a process related to a certain branch circuit, the value of the large current flag related to the other branch circuit is used as the value of the other branch circuit. The latest value of the large current flag may be used. In this case, the processing order of the branch circuit is not limited.

  The AD conversion means 115 of the current measuring device 110 converts the current value measured by the AC current sensor for the specific branch circuit from an analog value to a digital value, and “measurement data” and “correction data” in the data area 120. (Step S201).

  The CPU 114 of the current measuring device 110 determines whether or not “measurement data” held by the memory 116 is greater than the large current threshold for a specific branch circuit (step S202). If the “measurement data” is not greater than the large current threshold (step S202: No), the CPU 114 proceeds to the process of step S204. If the “measurement data” is larger than the large current threshold (step S202: Yes), the CPU 114 writes a value indicating a large current in the large current flag for the specific branch circuit (step S203), and proceeds to the process of step S208.

  The CPU 114 of the current measuring device 110 determines whether or not the “measurement data” held by the memory 116 is smaller than the small current threshold for a specific branch circuit (step S204). If the “measurement data” is not smaller than the small current threshold (step S204: No), the CPU 114 proceeds to the process of step S208. If the “measurement data” is smaller than the small current threshold (step S204: Yes), the CPU 114 proceeds to the process of step S206.

  The CPU 114 of the current measuring device 110 determines whether or not a large current flag is set for an adjacent branch circuit for a specific branch circuit (step S206). If the large current flag is not set in the adjacent branch circuit (step S206: No), the CPU 114 proceeds to the process of step S208. If the large current flag is set in the adjacent branch circuit (step S206: Yes), the CPU 114 corrects the current value held by the “correction data” in the memory 116 to zero for the specific branch circuit ( The process proceeds to step S207) and step S208.

  The CPU 114 of the current measuring device 110 displays “correction data” on the monitor device 400 for the specific branch electric circuit (step S208).

  Next, a specific example of processing according to the second embodiment of the present invention will be described.

  The current measuring device 110 stores the current values detected by the current sensors 308, 309, and 310 in “measurement data A”, “measurement data B”, and “measurement data C” in the data area 120 of the memory 116, respectively. (Step S201). The current measuring device 110 stores the current data detected by the current sensors 308, 309, and 310 in “correction data A”, “correction data B”, and “correction data C” in the data area 120 of the memory 116, respectively. (Step S201).

  In the following, it is assumed that “50 mA” is set in the “small current threshold” of the parameter area 121 and “10 A” is preset in the “large current threshold”.

  Assume that the “measurement data A” of the branch circuit 317 is “40 mA”, the “measurement data B” of the branch circuit 318 is “15 A”, and the “current data C” of the branch circuit 319 is “60 mA”. At this time, the “correction data” is set to the same value as the “measurement data” of the corresponding branch circuit.

  Since the “measurement data” of the branch circuit 318 is “15A” and larger than the “large current threshold” “10A” (step S202: Yes), the CPU 114 indicates that the “large current flag B” has a large current. The value to be expressed is stored (step S203), and the process proceeds to step S208. The CPU 114 displays the value “15A” of the “correction data B” on the monitor device 400 (step S208).

  Since the “measurement data” of the branch circuit 319 is “60 mA” and is smaller than the “large current threshold” “10 A” (step S202: No), the CPU 114 proceeds to the process of step S204. The CPU 114 proceeds to the process of step S208 because the “measurement data” of the branch circuit 319 is “60 mA” and is larger than the “small current threshold” “50 mA” (step S204: No). The CPU 114 displays the value “60 mA” of the “correction data C” on the monitor device 400 (step S208).

  Since the “measurement data” of the branch circuit 317 is “40 mA” and smaller than the “large current threshold value” “10 A” (step S202: No), the CPU 114 proceeds to the process of step S204. The CPU 114 proceeds to the process of step S206 because “measurement data” of the branch circuit 317 is “40 mA” and is smaller than “small current threshold” “50 mA” (step S204: Yes). The CPU 114 checks the “large current flag B” of the adjacent branch circuit 318 (step S206). Since the CPU 114 stores a value indicating a large current in the “large current flag B” (step S206: Yes), the CPU 114 writes zero in the “correction data A” of the branch circuit 317 (step S207). The process proceeds to S208. The CPU 114 displays the value “0A” of “correction data A” on the monitor device 400 (step S208).

  As described above, in the current measuring apparatus 110 of the present embodiment, an appropriate range of a large current value and a small current are set by setting an appropriate “large current threshold” and an appropriate “small current threshold”. The appropriate range of the current value can be adjusted. Therefore, the current measuring device 110 can correct a minute current that is affected by electromagnetic induction due to a large current flowing in an adjacent electric circuit in the measured minute current. In the current measuring device 110, a special current sensor having a compensation coil or the like for canceling an error voltage generated by an external magnetic field is not always necessary. Therefore, the current measuring device 110 can correct a minute current that is affected by electromagnetic induction due to a large current flowing in an adjacent electric circuit in a minute current measured using a normal current sensor.

  Moreover, since the current measuring device 110 of the present embodiment displays the measured current consumption on the external monitoring device 400, the user can easily monitor the current measurement value.

In the above description, the case where the current measuring device 110 measures the current consumption for each electric circuit has been described. However, the object measured by the current measuring device of the present embodiment is not limited to the current consumption. An object to be measured by the current measurement device of the present embodiment may be power consumption. For example, the current measuring device of the present embodiment may calculate the power consumption by multiplying the current consumption of each electric circuit by the voltage supplied to each electric circuit.
(Third embodiment)
Next, a third embodiment of the present invention in which the installation position of the alternating current sensor is made variable in the second embodiment described above will be described. In the following description, only differences from the second embodiment will be described, the same components as those in the second embodiment will be denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  A configuration in the present embodiment will be described.

  The configuration of the current measurement device 130 of the present embodiment is the same as that of the current measurement device 110 of the second embodiment, but the data configuration of the current measurement device 130 is different from that of the second embodiment.

  FIG. 8 is a block diagram illustrating an example of a data configuration of the current measurement device 130 according to the third embodiment of the present invention. In addition to the configuration of the data area 120 in the second embodiment of the present invention, the data area 122 of the memory 116 includes information on “installation position” to which the AC current sensor is attached and “adjacent to the AC current sensor on the right side”. It includes an area for storing “distance”. In addition to the configuration of the parameter area 121 in the second embodiment of the present invention, the parameter area 123 of the memory 116 stores an “adjacent distance threshold” that represents the maximum distance affected by the magnetic field due to the adjacent electric circuit. This area is further included.

  Next, the operation in this embodiment will be described.

  FIG. 9 is a diagram for explaining the configuration of a distribution board 300 according to the third embodiment of the present invention. The installation positions 323, 324, 325 and the like indicate positions where the alternating current sensor can be installed on the distribution board 300. For example, the alternating current sensor 308 is initially installed at the installation position 323, the alternating current sensor 309 is installed at the installation position 324, and the alternating current sensor 310 is installed at the installation position 325, but may be changed after that. There is. In order to be able to cope with a change in the installation position of the alternating current sensor, an area for storing the “installation position” of the alternating current sensor is added to the data area 122.

  Since the “installation position” is added to the data area 122, the current measuring device 130 determines whether or not the two branch circuits are adjacent even when the installation position of the AC current sensor is switched in the process of step S206 of FIG. Can be determined. For example, a serial number is assigned to each installation position 308, 309, 310, etc. in the distribution board 300 from the left, and when the value of “installation position” is an adjacent numerical value, it is determined that the alternating current sensor is adjacent. Is possible.

  In addition, “adjacent distance” is added to the data area 122, and “adjacent distance threshold” is added to the parameter area 123. Therefore, when the “adjacent distance” is longer than the “adjacent distance threshold”, the current measuring device 130 is not affected by the magnetic field, and when the “adjacent distance” is shorter than the “adjacent distance threshold” It can be determined that the electric paths are affected by the magnetic field. That is, the current measuring device 130 obtains the distance between adjacent electric circuits from the “adjacent distance” and compares it with the “adjacent distance threshold” in the process of step S206 of FIG. Even so, the presence or absence of the influence of the magnetic field between the electric paths can be determined. For example, the current measuring device 130 acquires the adjacent distance between the AC current sensors based on the “adjacent distance”, and determines that the adjacent distance is shorter than the “adjacent distance threshold” and is affected by the magnetic field. The process proceeds to step S207. On the other hand, if the adjacent distance is longer than the “adjacent distance threshold”, the current measuring device 130 determines that the current measuring apparatus 130 is not affected by the magnetic field, and proceeds to the process of step S208.

  As described above, the current measuring device 130 of the present embodiment holds information on the installation position of the AC current sensor. Therefore, in addition to the effect of the second embodiment of the present invention, the current measuring device 130 of the present embodiment has an effect that it can be used even when the installation position of the AC current sensor is changed.

  In addition, the current measurement device 130 according to the present embodiment holds information on an adjacent distance threshold indicating an adjacent distance between AC current sensors and a maximum distance affected by magnetism. Therefore, in addition to the effect of the second embodiment of the present invention, the current measuring device 130 of the present embodiment has an effect that it can be used even when the installation interval of the AC current sensor is not constant.

  In addition, although the electric current measurement apparatus in each embodiment mentioned above may be implement | achieved by a dedicated apparatus, it is realizable also with a computer (information processing apparatus). In this case, the computer reads a software program stored in a memory (not shown) to a CPU (not shown), and executes the read software program on the CPU, thereby obtaining an execution result, for example, a user interface. Output to. In the case of each of the above-described embodiments and modifications, the software program includes functions of the units of the current measuring device 100 shown in FIG. 1 and the units of the current measuring device 110 shown in FIG. It is only necessary that a description capable of realizing is provided. However, it is assumed that the measurement current holding unit 102 of the current measurement apparatus 100, the AD conversion unit 115 of the current measurement apparatus 110, and the memory 116 appropriately include hardware. In such a case, the software program (computer program) can be regarded as constituting the present invention. Furthermore, a computer-readable storage medium storing such a software program can also be understood as constituting the present invention.

  The present invention has been exemplarily described with the above-described embodiments and modifications thereof. However, the technical scope of the present invention is not limited to the scope described in the above-described embodiments and modifications thereof. It will be apparent to those skilled in the art that various modifications and improvements can be made to such embodiments. In such a case, new embodiments to which such changes or improvements are added can also be included in the technical scope of the present invention. This is clear from the matters described in the claims.

  INDUSTRIAL APPLICABILITY The present invention can be used in applications for monitoring current consumption or power consumption of electrical equipment connected to each branch circuit in distribution boards, power supply devices, power generation devices, and the like.

DESCRIPTION OF SYMBOLS 100 Current measuring apparatus 101 Inductive current correction means 102 Measuring current holding means 201, 202, 203, 204 Current sensor 301, 302, 303, 304 Electric circuit 110 Current measuring apparatus 114 CPU
115 AD conversion means 116 Memory 300 Distribution board 304 Main breaker 305, 306, 307 Branch breaker 308, 309, 310 AC current sensor 311, 312, 313 Load 317, 318, 319 Branch circuit 400 Monitor device 130 Current measurement device

Claims (10)

A current measuring device connected to a current sensor for measuring a current flowing in each circuit;
The current value of the first electric circuit is smaller than the first threshold value, and the current value of the second electric circuit adjacent to the first electric circuit is larger than the second threshold value, which is larger than the first threshold value. And a correction means for correcting the current value of the first electric circuit to zero when the current value is large.   The correction means holds information on the installation position of each current sensor, and determines whether or not the first electric circuit is close to the second electric circuit based on the information. Item 2. The current measuring device according to Item 1.   The information is a number indicating the order of arrangement of the current sensors, and the first current sensor that measures the current of the first electric circuit is the second current sensor that measures the current of the second electric circuit. 3. The current measuring device according to claim 2, wherein, when adjacent to each other, it is determined that the first electric circuit is close to the second electric circuit.   The information is a numerical value indicating a distance between the current sensors, and a first current sensor that measures a current of the first electric circuit, a second current sensor that measures a current of the second electric circuit, 3. The current measuring device according to claim 2, wherein when the distance between the first electric circuit and the second electric circuit is smaller than a third threshold value, the first electric circuit is determined to be close to the second electric circuit.   5. The current measuring device according to claim 1, further comprising: a power calculating unit that calculates power consumption in each of the electric paths based on the corrected current value. 6.   The current measuring apparatus according to claim 5, further comprising a display unit configured to display the power consumption on an external monitor device.   The current measuring device according to any one of claims 1 to 6, wherein each of the electric circuits is an electric circuit in which a main road that receives external power supply is branched in a distribution board. A main trunk receiving external power supply,
A distribution board comprising: a plurality of electric circuits branched from the main trunk line;
A current sensor for measuring a current flowing in each electric circuit; and a current value of a second electric circuit adjacent to the first electric circuit, wherein a current value of the first electric circuit is smaller than a first threshold value, A current measuring system comprising: a current measuring device including a correcting unit that corrects the current value of the first electric circuit to zero when the second threshold value is larger than the second threshold value. In the current measuring device connected to the current sensor that measures the current flowing in each circuit,
The current value of the first electric circuit is smaller than the first threshold value, and the current value of the second electric circuit adjacent to the first electric circuit is larger than the second threshold value, which is larger than the first threshold value. If the current is large, the current value of the first electric circuit is corrected to zero. A current measuring device connected to a current sensor for measuring a current flowing in each circuit;
The current value of the first electric circuit is smaller than the first threshold value, and the current value of the second electric circuit adjacent to the first electric circuit is larger than the second threshold value, which is larger than the first threshold value. A current measurement program for causing a computer to execute a correction process for correcting the current value of the first electric circuit to zero.

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