JP2007298414A - Electric power measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power measuring instrument having an exchangeable electric current detector, which reducing the work for individually setting conversion information specific to each electric current detector. <P>SOLUTION: In the electric current detector 121 of the electric power measuring instrument comprising the body 100 of the electric power measuring instrument and the replaceable electric current detector 121, a means of showing conversion information of the electric current detector is provided, and the conversion information is made detectable by a controller 170 in the body 100. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power measuring apparatus that measures the amount of power used in a system under measurement.

2. Description of the Related Art Conventionally, power measuring devices that measure the amount of power used and the power used in general households, factories, and offices have become widespread. The power measuring apparatus includes a power detection unit that measures the power used and the amount of power used in the system to be measured, a control unit that edits the power used detected by the power detection unit, and data edited by the control unit. And a display unit for displaying. (For example, Patent Document 1)
JP 2004-85413 A (Page 4, FIG. 2)

  2. Description of the Related Art Conventionally, power measuring devices that measure the amount of power used and power used by ordinary households, factories, and offices have become widespread. The power measurement device detects the voltage and current of the system under measurement, and multiplies the detected voltage value and current value to create measurement data related to the power amount and power. Usually, a current transformer or the like is used as a current sensor for current detection.

In addition, there is a power measuring device that can exchange current sensors having different rated currents according to the amount of current used in the system to be measured for the purpose of enabling measurement of a wide range of current values.

  However, in a power measuring device in which the current sensor can be replaced, conversion information such as a conversion ratio, a ratio error, and a phase angle error must be input to the power measuring device main body with a key switch or the like. It was. Such an input operation is troublesome for an operator and causes an input error.

  An object of the present invention is to provide a power measuring device that does not require a user to input conversion information for each current sensor into the main body of the power measuring device.

To achieve the above object, a power measuring apparatus according to the present invention includes a current sensor for detecting a current of a system under measurement, a first connector connected to the current sensor, and an electrode of the first connector. A current detector connected to and connected to the current sensor in accordance with conversion information; voltage input means for inputting a voltage of the system under measurement; and a first connector provided in the current detector. A second connector that engages with, a power calculating means for calculating a voltage input to the voltage input means and a signal from the current sensor from the second connector;
A power measuring instrument main body comprising a control unit that edits data according to a result calculated by the power calculating means and conversion information of the current sensor of the current detector obtained via the second connector; It is characterized by having.

  According to the present invention, it is possible to provide a power measuring device that does not require a user to input conversion information for each current transformer into the power measuring device main body.

  Examples of the present invention will be described below.

  A first embodiment of a measuring instrument according to the present invention will be described with reference to FIGS.

  In FIG. 1, reference numeral 100 denotes a power measuring device main body, which incorporates internal circuits and the like of each part constituting the power measuring device.

  Reference numeral 110 denotes a voltage input line made of a copper wire or the like, and inputs a voltage between lines of the system under measurement to the power measuring apparatus main body 100.

  Reference numerals 121, 122, and 123 denote current detectors, 121 for current measurement of a maximum of 120A, 122 for current measurement of a maximum of 30A, and 123 for current measurement of a maximum of 5A. One corresponding current detector is combined with the power measuring apparatus main body 100. It should be noted that the maximum current that can be measured by the current detector is an example, and it is of course possible to deal with other maximum currents. FIG. 2 shows a usage state of the power measuring device in which the current detector 121 is attached to the power measuring device main body 100.

Reference numerals 131, 132, and 133 are current sensors, each of which includes a current transformer or the like, and converts the current of the system under measurement into a low-level current. Reference numeral 131 denotes a current sensor for measuring a maximum current of 120 A, 132 a current sensor for measuring a maximum current of 30 A, and 133 a current sensor for measuring a maximum current of 5 A.

Reference numerals 141, 142, and 143 are connector portions made of resin or the like with a built-in metallic electrode, and engaged with a connector portion 150 on the power measuring device main body 100 side, which will be described later, from the current sensors 131, 132, and 133, respectively. The signal is transmitted to the power measuring apparatus main body 100.

Reference numeral 150 denotes a connector part of the power measuring apparatus main body 100, which is made of a resin or the like with a built-in metallic electrode, and engages with the connector part 141, 142, or 143 to transmit an electric signal to an internal circuit of the power measuring apparatus main body 100. To do.

Reference numeral 160 denotes a power calculation unit which is composed of a circuit combining an analog-digital converter and a multiplication circuit, and the like. The voltage of the system under test input from the voltage input line 110 and the low level from the current detector 121, 122 or 123. Is multiplied by the signal converted into the current of the current and converted into calculation data that is directly proportional to the power used by the system under measurement.

Reference numeral 170 denotes a control unit configured by a microcomputer or the like, which receives calculation data from the used power detection unit 160, edits it as power data, and controls storage and display. Here, the power data refers to data relating to the usage status of the consumer, such as power consumption, total accumulated power consumption, and power consumption for each time period.

A display unit 180 includes a liquid crystal display or the like, and displays the edited power data under the control of the control unit 170.

A communication unit 190 includes an interface circuit such as a current loop, and is connected to a telephone line or a network via an external transmission control device. Under the control of the control unit 170, the edited power data is transmitted to the outside.

The current detectors 121, 122, and 123 have connector portions 141, 142, and 143, respectively. Furthermore, the connector part 141 has electrodes 141a, 141b, 141c, 141d, 141e, and 141f, and the electrodes are electrodes 150a, 150b, 150c, 150d, 150e of the connector part 150 on the power measuring device main body 100 side. 150f is electrically engaged with each other. Similarly, when the current detector 122 is attached to the power measuring apparatus main body 100, the electrodes 142a, 142b, 142c, 142d, 142e, and 142f of the connector portion 142 are similarly attached. When the current detector 123 is attached, the electrode 143a of the connector portion 143 is attached. , 143b, 143c, 143d, 143e, and 143f are electrically engaged with the electrodes 150a, 150b, 150c, 150d, 150e, and 150f of the connector unit 150 on the power measuring device main body 100 side, respectively.

The electrodes 141a and 141b of the connector part 141 transmit signals from the current sensor 131 to the electrodes 150a and 150b of the connector part 150. The current sensor 131 is for measuring the maximum current 120A, and converts the current of the system under measurement into a low level current at a conversion ratio of 1/12000, for example. The current sensor 132 is for measuring the maximum current 30A, for example, at a conversion ratio of 1/3000, and the current sensor 133 is for measuring the maximum current 5A, for example, the current of the system under measurement at a conversion ratio of 1/500. Is converted to a low level current.

The power usage detector 160 performs analog-to-digital conversion on the voltage of the system under test input from the voltage input line 110 and the low-level current converted by the current detector 121, further multiplies them, and uses the system under test. Convert to calculation data that is directly proportional to power.

For example, when the voltage of the system to be measured is AC 100 V, the current is AC 120 A, and the power factor is 1.0, the current detector 121 is combined with the power measuring apparatus main body 100 to perform measurement. The ratio is 1/12000, and the current of the system under measurement of 120 A is converted to 10 mA, so the power calculation unit 160 outputs calculation data equivalent to 100 V × 10 mA = 1 W.

The electrode 141e of the connector part 141 of the 120A current detector 121 is electrically connected to 141f through a conducting wire 141g. Therefore, when the current detector 121 is attached to the power measuring device main body 100 by engaging the connector unit 141 with the connector unit 150, the control unit 170 has the electrodes 150e and 150f of the connector unit 150 in a conductive state. And the current detector 121 for 120A measurement is recognized as being connected to the power measuring apparatus 100. When the electrodes 150d and 150f of the connector part 150 are in a conductive state, the 30A current detector 122 is connected. When the electrodes 150c and 150f of the connector part 150 are in a conductive state, a current detector for 5A. It is recognized that 123 is connected.

  The control unit 170 receives the calculation data from the power calculation unit 160 and edits the power data. Here, the power data refers to data relating to the usage status of the consumer, such as power consumption, total accumulated power consumption, and power consumption for each time period.

The control unit 170 that recognizes that the current detector 121 is connected multiplies the stored conversion multiplier “12000” by the calculation data from the power calculation unit to create power data. The conversion multiplier is the reciprocal of the conversion ratio of the current converter, and the conversion multipliers of the replaceable current detectors 121, 122, and 123 are stored in the storage unit in the control unit 170 at the time of manufacture. In the case of the 30 A current detector 122, the conversion multiplier is “3000” which is the inverse of the conversion ratio 1/3000, and in the case of the 5 A current detector 123, “500” which is the inverse of the conversion ratio 1/500. .

In this way, in a power measurement device having a current detector that can be exchanged depending on the magnitude of the measurement current, in order to determine the type of current detector to which the control unit 170 is connected, currents having different current conversion ratios are used. Even when the detector is replaced, it is not necessary for the user to input data such as a conversion multiplier to the power measuring apparatus main body.

  As described above, by using this embodiment, it is possible to provide a power measuring device that does not require the user to input conversion information to the power measuring device main body.

  A second embodiment of the measuring instrument according to the present invention will be described with reference to FIG. About each part of this Example 2, the same part as each part of the measuring instrument of Example 1 shown in FIG. 1 is shown with the same code | symbol.

  The difference between the second embodiment and the first embodiment is that, in the first embodiment, the connector 141 of the current detector 121 is provided with a conducting wire 141g representing the conversion information of the current detector. 320 is provided with switches 342c, 342d, and 342e representing the conversion information of the current detector in the connector section 340. The switches 342c, 342d, and 342e are provided between the electrodes 341c, 341d, and 341e and the electrode 341f, respectively, and represent 3-bit information of 0 to 7 by their conduction.

The conduction and non-conduction of the switches 342c, 342d, and 342e are detected by the control unit 170 in the power measurement apparatus main body 300. For example, when the switch 342c is conductive and the switches 342d and 342e are non-conductive, the control unit 170 detects the code “100”. The 3-bit code is used as information representing “conversion multiplier”, “ratio error”, “phase angle error”, etc., which are conversion information of the current detector.

  When the 3-bit code represents “conversion multiplier” which is one of the conversion information, the control multiplier 170 in the power measuring apparatus main body 300 stores the conversion multiplier as shown in FIG. The current detector 321 includes a 120A current sensor 131, and the conversion ratio is 1/12000. The switches 342c, 342d, and 342e are “conductive”, “non-conductive”, and “non-conductive”, respectively, and the control unit 370 detects the code “100”. The controller 170 detecting the code “100” recognizes that the conversion multiplier is “12000”. Accordingly, the control unit 170 multiplies the conversion data “12000” by the calculation data from the power calculation unit 160 to calculate power data.

  When the 3-bit code represents the “ratio error” of the current detector 321 which is one of the conversion information, the controller 170 in the power measuring apparatus main body 300 stores the ratio error as shown in FIG. . Here, the ratio error means an error related to the current conversion ratio of the current sensor 131. For example, when the current of the system under measurement is 120A, the current sensor 131 outputs only 9.9mA even though it is designed to output 10mA. If not, the ratio error is -1%. The current detector 321 is inspected at the time of factory shipment, and the ratio error of the current sensor 131 is set by the switches 342c, 342d, and 342e. For example, when the ratio error is −0.2%, the code is “010”, so the switches 342c, 342d, and 342e are “non-conductive”, “conductive”, and “non-conductive”, respectively, and the ratio error is −0.6%. In this case, since the code is “110”, the switches 342c, 342d, and 342e are set to “conductive”, “conductive”, and “non-conductive”, respectively.

For example, when the switches 342c, 342d, and 342e are “conductive”, “conductive”, and “non-conductive”, the control unit 370 detects the code “110”. The control unit 170 detecting the code “110” recognizes that the ratio error is “−0.6%”. However, the control unit 170 considers that the ratio error of the current sensor 131 is “−0.6%” and divides the calculation data from the power calculation unit 160 by “0.994” to calculate the power data.

  When the 3-bit code represents the “phase angle error” of the current detector 321 which is one of the conversion information, the phase angle error as shown in FIG. Keep it. Here, the phase angle error refers to an error related to the phase angle generated during current conversion of the current sensor 131. For example, when the phase angle of the output current of the current sensor 131 matches the current of the system under measurement, the phase angle error is When the angle is 0 ° but is advanced by 0.5 °, the phase angle error is −0.5 °. The current detector 321 is inspected at the time of shipment from the factory, and the phase angle error of the current sensor 131 is set by the switches 342c, 342d, and 342e. For example, when the phase angle error is −0.3 °, the code is “011”, so that the switches 342c, 342d, and 342e are “non-conductive”, “conductive”, and “conductive”, respectively, and the ratio error is −0.7 °. In this case, since the code is “111”, the switches 342c, 342d, and 342e are set to “conductive”, “conductive”, and “conductive”, respectively.

For example, when the switches 342c, 342d, and 342e are “conductive”, “conductive”, and “conductive”, the control unit 370 detects the code “111”. The control unit 170 that has detected the code “111” recognizes that the phase angle error is “−0.7 °”. However, the control unit 170 calculates the power data based on the calculation data from the power calculation unit 160 in consideration that the phase angle error of the current sensor 131 is “−0.7 °”.

In this way, even when the current detector is replaced with respect to the power meter main body, the control unit 170 acquires information on the current detector from the current detector. It is not necessary for the user to input data such as “conversion multiplier”, “ratio error”, and “phase angle error” to the power measurement apparatus main body. Further, since the conversion information is expressed by a combination of a plurality of switches, it is possible to acquire more detailed information from the current detector.

  As described above, by using this embodiment, it is possible to provide a high-accuracy power measurement device that does not require the user to input conversion information to the power measurement device main body.

  Embodiment 3 of a measuring instrument according to the present invention will be described with reference to FIG. About each part of this Example 3, the same part as each part of the measuring instrument of Example 1 shown in FIG. 1 is shown with the same code | symbol.

  The difference between the third embodiment and the first embodiment is that, in the first embodiment, the connector 141 of the current detector 121 is provided with the conductor 141g representing the conversion information of the current detector. 720 is provided with a resistor 742 representing the conversion information of the current detector in the connector portion 740, and the control portion 770 includes an analog-digital converter. The resistor 742 is provided between the electrodes 741c and 741d, and represents the conversion information such as “conversion multiplier”, “ratio error”, “phase angle error”, etc. of the current sensor 131 by its resistance value. The control unit 770 includes an analog-digital converter that can measure a resistance value.

When the current detector 720 is attached to the power measuring apparatus main body 700 with the connector portions 740 and 750, the resistance value of the resistor 742 is in the power measuring apparatus main body 700 via the electrodes 750c and 741c and 750d and 741d. It is detected by the control unit 770. The resistance value represents conversion information such as “conversion multiplier”, “ratio error”, and “phase angle error” of the current detector 720.

  When the resistance value of the resistor 742 represents the “conversion multiplier” of the current detector 720, which is one of the conversion information, the relationship between the resistance value and the conversion multiplier is as shown in FIG. The information is stored in the control unit 770 in 700 at the time of factory shipment.

When the current detector 720 is shipped from the factory, a resistor 742 having a resistance value corresponding to the conversion multiplier of the current sensor 131 is attached between the electrodes 741c and 741d of the connector portion 740. For example, in the case of the 120 A current sensor 131, the conversion ratio is 1/12000, and thus the resistance value of the resistor 742 is 14.0 kΩ, which is a resistance value corresponding to the conversion multiplier “12000”. The resistor 742 may be a variable resistor, and the resistance value may be set by adjustment at the time of shipment from the factory.

For example, when the resistance value of the resistor 742 is 14.0 kΩ, the control unit 770 detects that the resistance value of the resistor 742 is 14.0 kΩ through the electrodes 750 c and 741 c and 750 d and 741 d of the connector units 750 and 740. To do. The control unit 770 that detects '14 .0 kΩ 'recognizes that the conversion ratio is “12000” from the relationship of FIG. However, considering that the conversion ratio of the current sensor 131 is “12000”, the control unit 770 calculates, as power data, a value obtained by multiplying the calculation data from the power calculation unit 160 by the conversion multiplier “12000”.

  When the resistance value of the resistor 742 represents the “ratio error” of the current detector 720, which is one of the conversion information, the relationship between the resistance value and the ratio error is a proportional relationship as shown in FIG. The information is stored in the control unit 770 in the main body 700 at the time of factory shipment. Here, the ratio error means an error related to the current conversion ratio of the current sensor 131. For example, when the current of the system under measurement is 120A, the current sensor 131 outputs only 9.9mA even though it is designed to output 10mA. If not, the ratio error is -1%. The current detector 721 is inspected at the time of shipment from the factory, and a resistor 742 having a resistance value corresponding to the ratio error of the current sensor 131 is attached between the electrodes 741c and 741d of the connector portion 740. The resistance value of the resistor 742 is, for example, 8.8 kΩ when the ratio error is −1.2%, and 12.6 kΩ when the ratio error is + 2.6%. The resistor 742 may be a variable resistor, and the resistance value may be set by adjustment at the time of shipment from the factory.

For example, when the resistance value of the resistor 742 is 12.6 kΩ, the control unit 770 determines that the resistance value of the resistor 742 is 12.6 kΩ via the electrodes 750 c and 741 c and 750 d and 741 d of the connector units 750 and 740. To detect. The control unit 770 that detects '12 .6 kΩ 'recognizes that the ratio error is “+ 2.6%” from the proportional relationship of FIG. However, the control unit 770 considers that the ratio error of the current sensor 131 is “+ 2.6%” and calculates a value obtained by dividing the calculation data from the power calculation unit 160 by “1.026” as power data.

  When the resistance value of the resistor 742 represents the “phase angle error” of the current detector 720 that is one of the conversion information, the relationship between the resistance value and the phase angle error is a proportional relationship as shown in FIG. The information is stored in the control unit 770 in the measuring apparatus main body 700 at the time of factory shipment. Here, the phase angle error refers to an error related to the phase angle generated during current conversion of the current sensor 131. For example, when the phase angle of the output current of the current sensor 131 matches the current of the system under measurement, the phase angle error is When the angle is 0 ° but is advanced by 0.5 °, the phase angle error is −0.5 °. The current detector 721 is inspected at the time of shipment from the factory, and a resistor 742 having a resistance value corresponding to the phase angle error of the current sensor 131 is attached between the electrodes 741c and 741d of the connector portion 740. The resistance value of the resistor 742 is, for example, 11.4 kΩ when the phase angle error is + 1.4 °, and 9.3 kΩ when the phase angle error is −0.7 °. The resistor 742 may be a variable resistor, and the resistance value may be set by adjustment at the time of shipment from the factory.

For example, when the resistance value of the resistor 742 is 9.3 kΩ, the control unit 770 detects that the resistance value of the resistor 742 is 9.3 kΩ via the electrodes 750 c and 741 c and 750 d and 741 d of the connector units 750 and 740. To do. The control unit 770 that detects '9.3 kΩ' recognizes that the phase angle error is “−0.7 °” from the proportional relationship of FIG. However, the control unit 770 calculates the power data based on the calculation data from the power calculation unit 160 taking into account that the phase angle error of the current sensor 131 is “−0.7 °”.

In this way, even when the current detector is replaced with respect to the power meter main body, the control unit 170 acquires information on the current detector from the current detector. It is not necessary for the user to input data such as “conversion multiplier”, “ratio error”, and “phase angle error” to the power measurement apparatus main body. Moreover, since conversion information such as continuous “ratio error” and “phase angle error” can be set by the resistor, a highly accurate power measuring device can be provided.

  As described above, by using this embodiment, it is possible to provide a high-accuracy power measurement device that does not require the user to input conversion information to the power measurement device main body.

The internal block diagram which shows the structure of Example 1 of the electric power measuring apparatus by this invention The block diagram which shows the attachment state of the power measuring device by this invention The internal block diagram which shows the structure of Example 2 of the electric power measuring apparatus by this invention Storage contents of control unit according to embodiment 2 of power measuring apparatus according to the present invention Storage contents of control unit according to embodiment 2 of power measuring apparatus according to the present invention Storage contents of control unit according to embodiment 2 of power measuring apparatus according to the present invention The internal block diagram which shows the structure of Example 3 of the power measuring device by this invention. Storage contents of control unit according to embodiment 3 of power measuring apparatus according to the present invention Storage contents of control unit according to embodiment 3 of power measuring apparatus according to the present invention Storage contents of control unit according to embodiment 3 of power measuring apparatus according to the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Power measuring device main body 110 Voltage input line 121 Current detector 122 Current detector 123 Current detector 131 Current sensor 132 Current sensor 133 Current sensor 141 Connector part 141a Electrode 141b Electrode 141c Electrode 141d Electrode 141e Electrode 141f Electrode 141g Conductor 142 Connector part 142a Electrode 142b Electrode 142c Electrode 142d Electrode 142e Electrode 142f Electrode 142g Conductor 143 Connector 143a Electrode 143b Electrode 143c Electrode 143d Electrode 143e Electrode 143f Electrode 143g Conductor 150 Connector 150a Electrode 150b Electrode 150c Electrode 150d Electrode 150f Electrode 150f Electrode 150f Electrode 150f Electrode 150f Electrode 170 Control Unit 180 Display Unit 190 Communication Unit 300 Power Measurement Device Main Body 320 Current Detector 340 Connector Unit 341a Electrode 341b Electrode 341c Electrode 341d Electrode 341e Electrode 341f Electrode 342c Switch 342d Switch 342e Switch 700 Power measuring device body 720 Current detector 740 Connector 741a Electrode 741b Electrode 741c Electrode 741d Electrode 742 Resistor 750 Connector 750a Electrode 750b Electrode 750c Electrode 770 controller

Claims (6)

A current sensor for detecting the current of the system under measurement;
A first connector connected to the current sensor;
A current detector comprising conduction means connected between the electrodes of the first connector and conducting according to conversion information of the current sensor;
Voltage input means for inputting the voltage of the system under measurement;
A second connector engaged with a first connector provided in the current detector;
Power calculating means for calculating a voltage input to the voltage input means and a signal from the current sensor from the second connector;
A power measuring instrument main body comprising a control unit that edits data according to a result calculated by the power calculating means and conversion information of the current sensor of the current detector obtained via the second connector; A power measuring device comprising: A current sensor for detecting the current of the system under measurement;
A first connector connected to the current sensor;
A current detector comprising a plurality of switches connected between the electrodes of the first connector and opened and closed corresponding to conversion information of the current sensor;
Voltage input means for inputting the voltage of the system under measurement;
A second connector engaged with a first connector provided in the current detector;
Power calculating means for calculating a voltage input to the voltage input means and a signal from the current sensor from the second connector;
A power meter main body comprising a control unit that edits data according to conversion results corresponding to opening / closing information of the plurality of switches obtained through the second connector and the result calculated by the power calculation means And a power measuring device. A current sensor for detecting the current of the system under measurement;
A first connector connected to the current sensor;
A current detector comprising a resistor connected between the electrodes of the first connector and having a resistance value corresponding to conversion information of the current sensor;
Voltage input means for inputting the voltage of the system under measurement;
A second connector engaged with a first connector provided in the current detector;
Power calculating means for calculating a voltage input to the voltage input means and a signal from the current sensor from the second connector;
A power measuring instrument main body comprising a control unit that edits data in accordance with the result calculated by the power calculating means and the conversion information corresponding to the resistance value of the resistor obtained through the second connector; A power measuring apparatus comprising: 4. The power measuring apparatus according to claim 1, wherein the conversion information is a conversion multiplier of the current sensor. 5. 4. The power measuring apparatus according to claim 2, wherein the conversion information is a ratio error of the current sensor. The power measurement apparatus according to claim 1, wherein the conversion information is a phase angle error of the current sensor.

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