JP2010121985A - Measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure power measurement errors of a wattmeter, without causing increase in the device cost. <P>SOLUTION: A processing section 5 performs: processing for outputting an inspection voltage Vt1 and acquiring a predetermined magnification α and a voltage value Vmv from the wattmeter 50, and calculating the value Vmu of multiplication of the predetermined magnification α with the inspection voltage Vt1; processing for outputting an inspection voltage Vt2 and acquiring a predetermined conversion rate β and a current value Imv from the wattmeter 50, and calculating the value Imu of multiplication of the conversion rate β with the inspection voltage Vt2; processing for outputting the inspection voltage Vt1 and a divided voltage Vd to a first and second input terminals 51 and 52 of the wattmeter 50 and acquiring a phase difference ϕ from the wattmeter 50; and power-error calculation processing for calculating an actual measurement value W1 of a power Wm that is an object of measurement by the wattmeter 50 on the basis of the voltage value Vmv, current value Imv, and phase difference ϕ, calculating a theoretical value W2 of the power Wm, by multiplying the multiplied value Vmu by the multiplied value Imu, and calculating the power measurement error We of the wattmeter 50. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a measuring apparatus for measuring a power measurement error of a power meter.

As a measuring device (calibration system) for measuring a power measurement error, a calibration system disclosed in Patent Document 1 below is known. This calibration system includes a power generation unit having a two-phase oscillator, a voltage generator and a current generator, and a standard power measuring instrument. In this calibration system, the AC voltage output from the voltage generator and the AC current output from the current generator are input to the power meter to be calibrated and the standard power measuring device to measure the power respectively. In this case, the power measurement error for the power measured by the calibrated power meter is measured as a difference from the power measured by the standard power meter. According to this calibration system, calibration that satisfies the stability is possible by calibrating the calibrated power meter so that the power measured by the calibrated power meter is equal to the power measured by the standard power meter. It has become.
JP-A-5-72311 (page 2-3, FIG. 5)

  However, the measurement apparatus (calibration system) has the following problems to be solved. In other words, this measuring apparatus requires three devices, ie, a two-phase oscillator, a voltage generator, and a current generator, so that there is a problem that the apparatus becomes expensive. Also, there are two types of wattmeters: one that directly measures current as in the above measuring device, and one that converts current into voltage using a current detection probe and inputs the latter. In some cases, the power measurement error may be measured with the current detection probe removed. However, in this case, there is a problem that calibration cannot be performed using the above-described measurement apparatus.

  The present invention has been made in view of such a problem, and mainly provides a measuring apparatus that can measure a power measurement error of a power meter that converts current into voltage and inputs the voltage without increasing the apparatus price. Objective.

  In order to achieve the above object, the measuring apparatus according to claim 1, a voltage calculation process for calculating a voltage value of the voltage to be measured by multiplying the first voltage input to the first voltage input terminal by a predetermined magnification, A current calculation process for calculating a current value of the current to be measured by multiplying the second voltage input to the two-voltage input terminal by a predetermined conversion rate, and detecting a phase difference between the first voltage and the second voltage A phase difference detection process, a power calculation process for calculating a measurement target power based on a voltage value of the measurement target voltage, a current value of the measurement target current, and the phase difference, the predetermined magnification, the predetermined conversion rate, and the measurement A measuring apparatus for measuring a measurement error of a wattmeter configured to be able to execute a data output process for outputting information indicating a voltage value of a target voltage, a current value of the current to be measured, and the phase difference to the outside. , Equipped with a processing unit The processing unit outputs a predetermined first inspection voltage to the first voltage input terminal, and acquires the voltage value of the predetermined magnification and the voltage to be measured included in the information output from the wattmeter. And a voltage value acquisition process for calculating a first multiplication value by multiplying the predetermined magnification and the first inspection voltage, and outputting a predetermined second inspection voltage to the second voltage input terminal from the wattmeter. The predetermined conversion rate and the current value of the current to be measured included in the output information are acquired, and a second multiplication value is calculated by multiplying the predetermined conversion rate and the second inspection voltage. Current value acquisition processing and outputting a predetermined third inspection voltage to the first voltage input terminal and outputting a fourth inspection voltage generated by dividing the third inspection voltage by resistance to the second voltage input terminal Output from the power meter A phase difference acquisition process for acquiring the phase difference included in the report, the voltage value of the acquired measurement target voltage, the current value of the acquired measurement target current, and the acquired phase difference And calculating an actual value of the measurement target power measured by the power meter, multiplying the first multiplication value and the second multiplication value to calculate a theoretical value of the measurement target power, and calculating the actual measurement value. And a power error calculation process for calculating a power measurement error for the measurement target power of the power meter based on the value and the theoretical value.

  According to a second aspect of the present invention, there is provided the measuring apparatus according to the first aspect, wherein a voltage output unit that generates and outputs a test voltage having a voltage value set by the processing unit, and the test voltage is divided into a predetermined amount. A resistance voltage dividing unit that divides the voltage by a voltage ratio and outputs the divided voltage, and a voltage selection that inputs the inspection voltage and the divided voltage and outputs one of the voltages designated by the processing unit And the processing unit sets the voltage value of the test voltage to a predetermined voltage value and outputs the voltage as the first test voltage in the voltage value acquisition process, In the current value acquisition process, the voltage value of the test voltage is set to a predetermined voltage value for the voltage output unit, and the test voltage is specified to the voltage selection unit and output as the second test voltage. Let In the phase difference acquisition process, the voltage output unit sets the voltage value of the inspection voltage to a predetermined voltage value and outputs the voltage as the third inspection voltage, and the voltage selection unit outputs the divided voltage. A voltage is designated and output as the fourth inspection voltage.

  In the measuring apparatus according to claim 1, the processing unit outputs a predetermined first inspection voltage to the first voltage input terminal to acquire a predetermined magnification and a voltage value of the voltage to be measured from the wattmeter, and the predetermined magnification and the first A voltage value acquisition process for calculating a first multiplication value by multiplying by one inspection voltage, a predetermined second inspection voltage is output to the second voltage input terminal, and a predetermined conversion rate and a current value of the current to be measured are output from the wattmeter Current value acquisition processing for calculating the second multiplication value by multiplying the predetermined conversion rate and the second inspection voltage, and outputting a predetermined third inspection voltage to the first voltage input terminal and performing the third inspection A fourth test voltage generated by resistance-dividing the voltage to the second voltage input terminal, a phase difference acquisition process for acquiring a phase difference output from the power meter, and a voltage value of the acquired measurement target voltage; Wattmeter based on current value and phase difference of current to be measured The measured value of the measured power to be measured is calculated, and the theoretical value of the measured power is calculated by multiplying the first multiplied value and the second multiplied value, and the power meter is measured based on the measured value and the theoretical value. A power error calculation process for calculating a power measurement error for the target power is executed.

  Therefore, according to this measuring apparatus, unlike the conventional measuring apparatus that requires three devices, ie, a two-phase oscillator, a voltage generator, and a current generator, the two-phase oscillator and the current generator can be eliminated. Therefore, the apparatus can be configured at low cost. Moreover, according to this measuring apparatus, since the 4th test voltage produced | generated by resistance-dividing this 3rd test voltage together with a 3rd test voltage can be output to a wattmeter, the structure which uses a current detection probe The power measurement error for the wattmeters can be measured without using a current detection probe.

  According to the measuring device of claim 2, in the voltage value acquisition process, the test voltage of the predetermined voltage value is applied to the first power meter without manually changing the wiring between the measuring device and the power meter. In the current value acquisition process, a test voltage having a predetermined voltage value is output to the second voltage input terminal of the wattmeter as a second test voltage, and in the phase difference acquisition process. Automatically outputs a test voltage of a predetermined voltage value to the first voltage input terminal of the wattmeter as the third test voltage and also outputs a divided voltage of the test voltage to the second voltage input terminal as the fourth test voltage. Therefore, the power measurement error of the power meter can be measured easily and in a short time.

  Hereinafter, the best mode of a measuring apparatus according to the present invention will be described with reference to the accompanying drawings.

  First, a calibration target wattmeter (hereinafter also simply referred to as “wattmeter”) 50 calibrated using the measuring apparatus 1 according to the present invention shown in FIG. 1 will be described with reference to FIG.

  The wattmeter 50 multiplies the voltage value V1v of the first voltage V1 inputted to the first voltage input terminals (hereinafter also simply referred to as “first input terminals”) 51, 51 by a predetermined magnification α to measure the voltage to be measured. Voltage calculation processing for calculating the voltage value Vmv of Vm and predetermined conversion into the voltage value V2v of the second voltage V2 input to the second voltage input terminal (hereinafter also simply referred to as “second input terminal”) 52, 52 A current calculation process for calculating the current value Imv of the measurement target current Im by multiplying by the rate β, a phase difference detection process for detecting the phase difference φ between the first voltage V1 and the second voltage V2, and a measurement target voltage Vm Power calculation processing for calculating the measurement target power Wm from a predetermined arithmetic expression (Vmv × Imv × cos φ) based on the voltage value Vmv, the current value Imv of the measurement target current Im, and the phase difference φ, a predetermined magnification α, and a predetermined conversion rate β, voltage value of the measurement target voltage Vm mv, is configured to be able to execute a data output process of outputting the current value Imv, and (information in the present invention) power meter data including a phase difference phi D1 from the data output terminal 53 to the outside of the measured current Im. In this example, as an example, in the wattmeter 50, a voltage detection probe with a magnification of 1 is connected to the first input terminals 51 and 51, and a current detection with a conversion magnification of 25 is connected to the second input terminals 52 and 52. A configuration in which a probe is connected is adopted. Therefore, corresponding to this configuration, the predetermined magnification α is defined as a numerical value “1”, and the predetermined conversion rate β is defined as a numerical value “25”.

  Next, the configuration of the measuring apparatus 1 will be described with reference to the drawings.

  1 includes a voltage output unit 2, a resistance voltage dividing unit 3, a voltage selection unit 4, a processing unit 5, a storage unit 6, a display unit 7, a first voltage output terminal (hereinafter simply referred to as “first output”). 8), a second voltage output terminal (hereinafter also simply referred to as “second output terminal”) 9, 9, and a data input terminal 10, and measures a power measurement error We for the wattmeter 50. And can be displayed.

  The voltage output unit 2 is composed of an AC voltage generator capable of arbitrarily setting an output voltage value, and as shown in FIG. 1, the voltage value set by the processing unit 5 (for example, two voltage values Vta and Vtb). A test voltage Vt1 (which is an AC voltage having a constant frequency and is a first test voltage according to the present invention) of the control data Ds1 output from the processing unit 5 (<Vta) is generated to generate a first voltage. Output from output terminals 8 and 8. In this example, as an example, the voltage value Vta is defined in advance as 600 volts and the voltage value Vtb is defined as 2 volts. The resistance voltage dividing unit 3 is configured by only a resistor, and divides the inspection voltage Vt1 into the divided voltage Vd at a predetermined voltage dividing ratio (in this example, 600: 2 as an example). In this example, the resistance voltage dividing unit 3 includes two resistors 3 a and 3 b connected in series as an example, and is disposed between the first output terminals 8 and 8. With this configuration, the resistance voltage divider 3 uses the voltage generated across the resistor 3b as the divided voltage Vd (= Vta (or Vtb) × 2/600), and the phase difference from the inspection voltage Vt1 is zero. Output in the state of.

  As shown in FIG. 1, the voltage selection unit 4 receives the inspection voltage Vt1 and the divided voltage Vd, and among the inspection voltage Vt1 and the divided voltage Vd specified by the control signal S1 output from the processing unit 5. Is output as the inspection voltage Vt2 (second inspection voltage in the present invention). As an example, the voltage selection unit 4 includes two on / off switches (hereinafter also simply referred to as “switches”) 4a and 4b, and two selection switches (hereinafter also simply referred to as “switches”) 4c and 4d. Each switch 4a-4d is connected and configured as follows. Specifically, the switch 4a is arranged between one first output terminal 8 of the two first output terminals 8 and 8 and one contact a of the switch 4c, and the switch 4b It is disposed between the first output terminal 8 and one contact a of the switch 4d. The switch 4c has a contact b connected to a connection point of the resistors 3a and 3b in the resistance voltage dividing section 3, and a common contact c connected to one of the second output terminals 9 and 9. 9 is connected. The switch 4d has a contact b connected to an end of the resistor 3b (the other first output terminal 8) in the resistance voltage dividing unit 3, and a common contact c connected to the other second output terminal 9. ing.

  The voltage selection unit 4 configured as described above is in a first output state in which the inspection voltage Vt1 specified by the control signal S1 is output as the inspection voltage Vt2 (the switches 4a and 4b are in the on state and the switches 4c and 4d). And the second output state in which the divided voltage Vd designated by the control signal S1 is output as the inspection voltage Vt2 (the switches 4a and 4b are in the off state, and The switch 4c, 4d shifts to one of the output states of the common contact c of the switch 4c, 4d connected to the contact b.

  The processing unit 5 includes a CPU (not shown) as an example, and based on an operation program stored in the storage unit 6, a voltage value acquisition process, a current value acquisition process, a phase difference acquisition process, and a power error calculation process Execute. The processing unit 5 outputs the control data Ds1 to the voltage output unit 2 to set the voltage value of the inspection voltage Vt1, and outputs the control signal S1 to the voltage selection unit 4 as the inspection voltage Vt2. A process for designating the output voltage and a display process for displaying the calculated power measurement error We on the display unit 7 are also executed. The storage unit 6 includes a semiconductor memory such as a ROM or a RAM, and stores an operation program for the processing unit 5 in advance. The storage unit 6 is also used as a work memory by the processing unit 5. The display unit 7 is configured by a display device, for example, and displays the power measurement error We input from the processing unit 5 on the screen.

  Next, the measurement operation for the power measurement error We of the wattmeter 50 by the measurement apparatus 1 will be described. As shown in FIG. 1, the first output terminals 8, 8, the second output terminals 9, 9 and the data input terminal 10 of the measuring device 1 are connected to the corresponding first input terminals 51, 51, It is assumed that the two input terminals 52 and 52 and the data output terminal 53 are electrically connected in advance one-on-one. In addition, the wattmeter 50 is in an operating state, and constantly executes a voltage calculation process, a current calculation process, a phase difference detection process, and a power calculation process. The data output process for outputting the wattmeter data D1 including the voltage value Vmv of the measured voltage Vm, the current value Imv of the measured current Im, and the phase difference φ from the data output terminal 53 to the outside is always executed. To do.

  In the measurement apparatus 1, in the operating state, first, the processing unit 5 executes a voltage value acquisition process. In this process, the processing unit 5 outputs the control data Ds1 to the voltage output unit 2 to output the inspection voltage Vt1 having the voltage value Vta (600 volts). As a result, the test voltage Vt1 is input to the first input terminals 51 and 51 of the wattmeter 50 as the first voltage V1. At this time, the wattmeter 50 measures the voltage value Vmv of the measurement target voltage Vm by measuring the voltage value of the first voltage V1 and multiplying the measured voltage value by a predetermined magnification α in the voltage calculation process. Is calculated. In this example, since the predetermined magnification α is the numerical value “1” as described above, the inspection voltage Vt1 itself becomes the measurement target voltage Vm. However, when the predetermined magnification α is the numerical value “2”, the inspection voltage Vt1 is doubled. The voltage obtained in this way becomes the measurement target voltage Vm. In this case, in the wattmeter 50, 600 volts obtained by multiplying the voltage value Vta (600 volts) by α (= 1) should be calculated if it is originally. The voltage value Vmv is calculated as 600.6 volts. Accordingly, the wattmeter data D1 including the voltage value Vmv (600.6 volts) of the measurement target voltage Vm is output from the wattmeter 50 to the measurement apparatus 1.

  The processing unit 5 acquires the wattmeter data D1 from the wattmeter 50 and stores the calculated voltage value Vmv (600.6 volts) for the measurement target voltage Vm included in the wattmeter data D1 in the storage unit 6. Remember. Further, the processing unit 5 multiplies a predetermined value α (= 1) included in the wattmeter data D1 and a voltage value Vta (600 volts) of the inspection voltage Vt1 output from the voltage output unit 2 by a value Vmu ( The first multiplication value in the present invention (600 volts in this example) is calculated and stored in the storage unit 6. Finally, the processing unit 5 calculates a voltage measurement error Ve for the wattmeter 50 from the voltage value Vmv (600.6 volts) and the multiplication value Vmu (600 volts) stored in the storage unit 6. Specifically, the voltage value of the first voltage V1 to be measured by the wattmeter 50 is the multiplication value Vmu (600 volts), while the voltage of the measurement target voltage Vm that is actually measured by the wattmeter 50. The value Vmv is 600.6 volts. For this reason, the processing unit 5 divides the difference (0.6 volts) of the voltage value Vmv (600.6 volts) from the multiplication value Vmu (600 volts) by the multiplication value Vmu (600 volts), thereby obtaining a wattmeter 50. A voltage measurement error Ve (0.1% in this example) is calculated and stored in the storage unit 6. Thereby, the voltage value acquisition process is completed.

  Next, the processing unit 5 executes a current value acquisition process. In this process, the processing unit 5 outputs the control data Ds1 to the voltage output unit 2 to output the inspection voltage Vt1 having the voltage value Vtb (2 volts). Further, the processing unit 5 outputs the control signal S1 to the voltage selection unit 4 to shift to the first output state in which the inspection voltage Vt1 is output as the inspection voltage Vt2. Thereby, the test voltage Vt1 is input to the second input terminals 52 and 52 of the wattmeter 50 as the second voltage V2. At this time, the wattmeter 50 measures the voltage value of the second voltage V2 in the current calculation process, and multiplies the measured voltage value by a predetermined conversion rate β to thereby obtain the current value of the measurement target current Im. Imv is calculated. In this example, since the predetermined conversion rate β is the numerical value “25” as described above, the current value Imv is obtained by multiplying the voltage value of the second voltage V2 (that is, the voltage value Vtb of the inspection voltage Vt1) by 25 times. In this case, the wattmeter 50 should calculate 50 amperes, which is obtained by multiplying the voltage value Vtb (2 volts) by β (= 25), if the current value Imv is 50 Suppose that it is calculated as .5 amperes. Thereby, the wattmeter data D1 including the current value Imv (50.5 amperes) of the measurement target current Im is output from the wattmeter 50 to the measurement apparatus 1.

  The processing unit 5 acquires the wattmeter data D1 from the wattmeter 50 and causes the storage unit 6 to store the current value Imv (50.5) included in the wattmeter data D1. Further, the processing unit 5 multiplies the predetermined conversion rate β (= 25) included in the wattmeter data D1 by the voltage value Vtb (2 volts) of the test voltage Vt1 output from the voltage output unit 2. (Second multiplication value in the present invention, 50 amps in this example) is calculated and stored in the storage unit 6. Finally, the processing unit 5 calculates a current measurement error Ie for the wattmeter 50 from the current value Imv (50.5 amperes) and the multiplication value Imu (50 amperes) stored in the storage unit 6. Specifically, the current value Imv to be measured in the wattmeter 50 is the multiplication value Imu (50 amperes), while the current value Imv actually measured in the wattmeter 50 is 50.5 amperes. . Therefore, the processing unit 5 divides the difference (0.5 ampere) of the current value Imv (50.5 amperes) from the multiplication value Imu (50 amperes) by the multiplication value Imu (50 amperes), thereby obtaining the power meter 50. Current measurement error Ie (1% in this example) is calculated and stored in the storage unit 6. Thereby, the current value acquisition process is completed.

  Subsequently, the processing unit 5 executes a phase difference acquisition process. In this process, the processing unit 5 outputs the control data Ds1 to the voltage output unit 2 to output the inspection voltage Vt1 having the voltage value Vta (600 volts). Further, the processing unit 5 outputs the control signal S1 to the voltage selection unit 4 to shift to the second output state in which the divided voltage Vd is output as the inspection voltage Vt2. As a result, the test voltage Vt1 having the voltage value Vta (600 volts) is input as the first voltage V1 to the first input terminals 51 and 51 of the wattmeter 50, and the divided voltage Vd is applied to the second input terminals 52 and 52. (2 volts = 600 × 2/600) is input as the second voltage V2. In this state, the wattmeter 50 executes the phase difference detection process to detect the phase difference φ between the first voltage V1 and the second voltage V2. In this example, it is assumed that 2 ° is detected as the phase difference φ. As a result, the wattmeter data D1 including the phase difference φ (2 °) is output from the wattmeter 50 to the measuring apparatus 1. The processing unit 5 acquires the wattmeter data D1 from the wattmeter 50 and causes the storage unit 6 to store the phase difference φ included in the wattmeter data D1. Thereby, the phase difference acquisition process is completed.

  In this example, in this phase difference acquisition process, the inspection voltage Vt1 output in the voltage value acquisition process is output to the first input terminals 51 and 51 of the wattmeter 50 as the third inspection voltage in the present invention. A configuration is adopted in which the divided voltage Vd output from the resistance voltage divider 3 based on the voltage Vt1 is output to the second input terminals 52 and 52 of the wattmeter 50 as the fourth inspection voltage in the present invention. A test voltage having a voltage value different from Vt1 is output to the first input terminals 51 and 51 of the wattmeter 50 as the third test voltage in the present invention, and the divided voltage output from the resistance voltage dividing unit 3 based on this test voltage. A configuration in which Vd is output to the second input terminals 52 and 52 of the wattmeter 50 as the fourth inspection voltage in the present invention may be employed.

  Next, the processing unit 5 executes a power error calculation process. In this process, first, the processing unit 5 determines the wattmeter based on the voltage value Vmv (600.6 volts), the current value Imv (50.5) and the phase difference φ (2 °) stored in the storage unit 6. The measurement target power Wm measured by the wattmeter 50 is calculated from the same predetermined arithmetic expression (Vmv × Imv × cosφ) used in the above 50 and stored in the storage unit 6 as the actual measurement value W1 of the wattmeter 50. Let In this example, 30311.8 (= 600.6 × 50.5 × cos (2 °)) is calculated and stored in the storage unit 6 as the actual measurement value W1 based on the arithmetic expression. Next, the processing unit 5 calculates the multiplication value Vmu (multiplication value (600 volts) of the predetermined magnification α (= 1) and the voltage value Vta (600 volts) of the inspection voltage Vt1) calculated in the voltage value acquisition process) and the current value. Measured by the wattmeter 50 by multiplying the multiplication value Imu calculated in the acquisition process (the predetermined conversion rate β (= 25) and the multiplication value (50 amperes) of the voltage value Vtb (2 volts) of the inspection voltage Vt1). The theoretical value W2 of the power to be measured Wm to be calculated is calculated and stored in the storage unit 6. In this example, 30000 (= 600 volts × 50 amps) is calculated as the theoretical value W 2 and stored in the storage unit 6. Subsequently, the processing unit 5 determines the power measurement error We (= (W1-W2) for the measurement target power Wm measured by the wattmeter 50 based on the actual measurement value W1 and the theoretical value W2 stored in the storage unit 6. ) × 100 / W2) is calculated and stored in the storage unit 6. Thereby, the power error calculation process is completed.

  Finally, the processing unit 5 executes display processing for causing the display unit 7 to display the calculated voltage measurement error Ve, current measurement error Ie, and power measurement error We for the wattmeter 50. As a result, the voltage measurement error Ve, the current measurement error Ie, and the power measurement error We are displayed on the display unit 7, so that the measurement error for the wattmeter 50 can be confirmed. Further, calibration for the voltage measurement of the wattmeter 50 based on the voltage measurement error Ve, calibration for the current measurement of the wattmeter 50 based on the current measurement error Ie, and calibration for the power measurement of the wattmeter 50 based on the power measurement error We are performed. It is also possible to do.

  As described above, in this measurement apparatus 1, the processing unit 5 includes the predetermined power voltage data D <b> 1 output from the power meter 50 when the predetermined test voltage Vt <b> 1 is output to the first input terminals 51 and 51. The process obtains the magnification α and the voltage value Vmv of the measurement target voltage Vm, calculates a multiplication value Vmu of the predetermined magnification α and the inspection voltage Vt1, and outputs the predetermined inspection voltage Vt2 to the second input terminals 52 and 52. Sometimes, the predetermined conversion rate β and the current value Imv of the measurement target current Im included in the wattmeter data D1 output from the wattmeter 50 are acquired, and the multiplication value Imu of the predetermined conversion rate β and the inspection voltage Vt2 is obtained. The calculated voltage and the test voltage Vt1 are output to the first input terminals 51 and 51 of the wattmeter 50 as the third test voltage and the divided voltage Vd generated by dividing the test voltage Vt1 by the resistance voltage divider 3. A process of acquiring the phase difference φ included in the wattmeter data D1 output from the wattmeter 50 when the fourth test voltage is output to the second input terminals 52, 52 of the wattmeter 50, and each of these processes The actual measurement value W1 of the measurement target power Wm measured by the wattmeter 50 is calculated based on the voltage value Vmv of the measurement target voltage Vm, the current value Imv of the measurement target current Im, and the phase difference φ acquired in step S3, and the multiplication value Vmu. Power value for calculating a power measurement error We for the measurement target power Wm of the wattmeter 50 based on the actual measurement value W1 and the theoretical value W2 The calculation process is executed.

  Therefore, according to this measuring apparatus 1, unlike the conventional measuring apparatus that requires three devices, ie, a two-phase oscillator, a voltage generator, and a current generator, the two-phase oscillator and the current generator can be made unnecessary. Therefore, the apparatus can be configured at a low cost. Further, according to this measuring apparatus 1, since the divided voltage Vd obtained by dividing the inspection voltage Vt1 can be output to the wattmeter 50 as the inspection voltage Vt2 together with the inspection voltage Vt1, the current detection probe is used. The power measurement error We for the wattmeter 50 can be measured without using a current detection probe.

  Further, in the measurement apparatus 1, the processing unit 5 causes the voltage output unit 2 to output the inspection voltage Vt1 having the predetermined voltage value Vta in the voltage value acquisition process, and the voltage output unit 2 in the current value acquisition process. The test voltage Vt1 having a predetermined voltage value Vtb is output to the voltage selector 4, the test voltage Vt1 is output as the test voltage Vt2 to the voltage selection unit 4, and the voltage output unit 2 is predetermined for the phase difference acquisition process. Is output, and the voltage selection unit 4 is caused to select the divided voltage Vd of the inspection voltage Vt1 output from the resistance voltage dividing unit 3 and output it as the inspection voltage Vt2.

  Therefore, according to this measuring apparatus 1, the inspection voltage Vt1 of the predetermined voltage value Vta is applied to the wattmeter 50 in the voltage value acquisition process without manually changing the wiring between the measuring apparatus 1 and the wattmeter 50. In the current value acquisition process, the test voltage Vt1 having a predetermined voltage value Vtb is output as the test voltage Vt2 to the second input terminals 52 and 52 of the wattmeter 50, and the phase difference is output. In the acquisition process, the test voltage Vt1 having a predetermined voltage value Vta is output to the first input terminals 51 and 51 of the wattmeter 50, and the divided voltage Vd of the test voltage Vt1 is set as the test voltage Vt2 to the second input terminals 52 and 52. Can be automatically executed, so that the measurement error (voltage measurement error Ve, current measurement error Ie, and power measurement error We) of the wattmeter 50 is simple and short. It can be measured.

  In addition, this invention is not limited to said structure. For example, instead of the configuration for measuring the voltage measurement error Ve, the current measurement error Ie, and the power measurement error We for the power meter 50, the voltage measurement error Ve and the power measurement error We, the current measurement error Ie and the power measurement error We, or It may be configured to measure only the power measurement error We.

  In addition, since the resistance voltage dividing unit 3 is composed of only a resistor, the phase difference between the test voltage Vt1 and the divided voltage Vd output by the resistor voltage dividing unit 3 by dividing the test voltage Vt1 is zero. As described above, the example in which this phase difference is not taken into account has been described above. However, the inside of the resistance voltage dividing unit 3, the wiring between the voltage output unit 2 and the resistance voltage dividing unit 3, the voltage dividing unit 3 and the voltage Even if the resistance voltage dividing unit 3 is composed of only a resistor due to the stray capacitance existing between the wiring lines to the selection unit 4, the phase difference φ1 between the test voltage Vt1 and the divided voltage Vd May occur. In this case, when the phase difference φ1 cannot be ignored, the phase difference φ1 generated in the measuring apparatus 1 is measured in advance, and the actual measurement value W1 of the measurement target power Wm for the wattmeter 50 in the power error calculation process is calculated. At this time, the phase difference φ1 may be taken into account. Thereby, the power measurement error We for the wattmeter 50 can be measured more accurately.

  In addition, when the switches 4a and 4b are provided in the voltage selection unit 4 and the divided voltage Vd is output as the inspection voltage Vt2, the switches 4a and 4b are turned off to minimize the influence of the inspection voltage Vt1 on the inspection voltage Vt2. In the case where this influence can be ignored, the switches 4a and 4b are omitted, the contact a of the switch 4c is connected to the first input terminal 51, and the contact a of the switch 4d. Can be connected to the other first input terminal 51. According to this configuration, since the configuration of the voltage selection unit 4 can be simplified, it is possible to further reduce the cost of the voltage selection unit 4 and consequently the product cost of the measuring apparatus 1.

  In the above example, the divided voltage Vd output from the resistance voltage divider 3 when the inspection voltage Vt1 (600 volts) in the voltage value acquisition process is divided by the resistance voltage divider 3 is the current value acquisition process. The voltage dividing ratio of the resistance voltage dividing unit 3 is defined so as to be the same as the voltage value of the inspection voltage Vt1 (2 volts in the above example), but is not limited thereto. That is, the divided voltage Vd obtained by dividing the inspection voltage Vt1 may be any voltage as long as it is within the input rated voltage range for the second input terminals 52 and 52 of the wattmeter 50. Therefore, the divided voltage Vd is The voltage dividing ratio of the resistance voltage dividing unit 3 can be arbitrarily set within a range that falls within the input rated voltage range.

1 is a block diagram showing a configuration of a measuring device 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measuring apparatus 2 Voltage output part 3 Resistance voltage dividing part 4 Voltage selection part 5 Processing part 50 Wattmeter 51 1st input terminal 52 2nd input terminal 53 Data output terminal alpha Predetermined magnification beta Predetermined conversion rate φ Phase difference Ie Current measurement error Im Current to be measured Imu Multiplication value (second multiplication value)
V1 first voltage V2 second voltage Vd divided voltage Ve voltage measurement error Vm voltage to be measured Vmu multiplication value (first multiplication value)
Vt1, Vt2 Inspection voltage We Power measurement error Wm Power to be measured

Claims (2)

Voltage calculation processing for calculating the voltage value of the voltage to be measured by multiplying the first voltage input to the first voltage input terminal by a predetermined magnification, and predetermined conversion to the second voltage input to the second voltage input terminal A current calculation process for calculating a current value of a current to be measured by multiplying a rate; a phase difference detection process for detecting a phase difference between the first voltage and the second voltage; a voltage value of the voltage to be measured; Power calculation processing for calculating power to be measured based on the current value of the current to be measured and the phase difference, the predetermined magnification, the predetermined conversion rate, the voltage value of the voltage to be measured, the current value of the current to be measured, and the current A measurement device that measures a measurement error of a wattmeter configured to be able to execute data output processing that outputs information indicating a phase difference to the outside,
With a processing unit,
The processing unit
A predetermined first inspection voltage is output to the first voltage input terminal to obtain the predetermined magnification and the voltage value of the voltage to be measured included in the information output from the power meter, and the predetermined voltage A voltage value acquisition process for calculating a first multiplication value by multiplying the magnification by the first inspection voltage;
Obtaining the predetermined conversion rate and the current value of the current to be measured included in the information output from the power meter by outputting a predetermined second inspection voltage to the second voltage input terminal, and A current value acquisition process for calculating a second multiplication value by multiplying a predetermined conversion rate and the second inspection voltage;
A predetermined third inspection voltage is output to the first voltage input terminal, and a fourth inspection voltage generated by resistance-dividing the third inspection voltage is output to the second voltage input terminal. A phase difference acquisition process for acquiring the phase difference included in the output information;
Based on the acquired voltage value of the acquired measurement target voltage, the acquired current value of the measured current, and the acquired phase difference, an actual measurement value of the measurement target power measured by the power meter is calculated. And calculating a theoretical value of the measurement target power by multiplying the first multiplication value and the second multiplication value, and based on the actual measurement value and the theoretical value, for the measurement target power of the wattmeter A measurement apparatus that executes a power error calculation process for calculating a power measurement error. A voltage output unit that generates and outputs a test voltage having a voltage value set by the processing unit;
A resistance voltage dividing unit that divides the inspection voltage by a predetermined voltage dividing ratio and outputs the divided voltage;
A voltage selection unit that inputs the inspection voltage and the divided voltage and outputs one of the voltages specified by the processing unit;
The processor is
In the voltage value acquisition process, the voltage output unit is set to the voltage value of the inspection voltage to a predetermined voltage value and output as the first inspection voltage,
In the current value acquisition process, the voltage value of the test voltage is set to a predetermined voltage value for the voltage output unit, and the test voltage is specified to the voltage selection unit to be used as the second test voltage. Output
In the phase difference acquisition process, the voltage output unit sets the voltage value of the inspection voltage to a predetermined voltage value and outputs the voltage as the third inspection voltage, and the voltage selection unit outputs the divided voltage. The measuring apparatus according to claim 1, wherein a voltage is designated and output as the fourth inspection voltage.

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