JP6331453B2 - Voltage measuring device and voltage measuring method - Google Patents

Description

  The present invention relates to a voltage measuring device and a voltage measuring method for measuring an alternating voltage applied to a conductor covered with an insulator.

  Conventionally, as disclosed in Patent Documents 1 and 2, a technique for measuring a voltage applied to an insulated wire without bringing a measurement electrode into contact with a conductor of the insulated wire is known.

  The configurations described in Patent Documents 1 and 2 output a detection probe having a detection electrode capable of covering a part of the surface of the insulation coating of the insulated wire and a shield electrode covering the detection electrode, and a signal having a predetermined frequency. Using an oscillator. Specifically, a signal having a predetermined frequency is output from the oscillator, the signal is supplied to the detection electrode of the detection probe, and the impedance between the detection electrode and the conductor is measured. Further, the current flowing out from the detection electrode due to the voltage applied to the conductor of the insulated wire is measured, and the voltage applied to the conductor is measured from this current and the impedance.

Japanese Patent Laid-Open No. 10-206468 (published August 7, 1998) JP 2002-365315 A (released on December 18, 2002)

  Here, the characteristic of each insulation coating of an insulated wire (measurement wire) varies greatly depending on temperature and humidity. For example, as shown in FIG. 10, the measurement voltage of the measurement wire having a frequency of 60 Hz and a specified voltage of AC200V is about three times as high as about 200V to about 600V when the humidity changes from about 45% to about 100%. Change. That is, the measurement voltage of the measurement wire varies greatly with humidity.

  Similarly to the above, the measurement voltage of the measurement wire having a frequency of 60 Hz and a specified voltage of AC 200 V is about 155 V to about 250 V when the temperature changes from about −5 ° C. to about 60 ° C. as shown in FIG. Until about 1.6 times. That is, the measurement voltage of the measurement wire varies greatly with temperature.

  Further, the relative dielectric constant of the insulation coating of the measurement wire has frequency characteristics, and the frequency characteristics vary depending on the material of the insulation coating as shown in FIG. In particular, PVC (polyvinyl chloride), which is frequently used as an insulating coating, has a remarkable difference in relative dielectric constant with respect to a difference in frequency.

  In a situation where the measurement voltage of the measurement wire is greatly influenced by the factors as described above, in the conventional configuration, as shown in FIG. 13, the frequency is greatly different from the measurement voltage (for example, frequency 60 Hz) of the measurement wire. By applying a signal (for example, a frequency of 6 kHz) to the measurement wire, the impedance between the conductor of the measurement wire and the detection electrode is measured, and the voltage (measurement voltage) of the conductor is obtained based on the impedance. For this reason, in the said conventional structure, it has the problem that the voltage of a measurement electric wire cannot be measured correctly.

  Therefore, an object of the present invention is to provide a voltage measurement device and a voltage measurement method that can accurately measure the voltage of a measurement electric wire that is a covered electric wire to be measured.

  The voltage measuring device of the present invention is a voltage measuring device that measures an AC voltage of a wire in a non-contact manner with a conductor constituting the wire, and a first capacitance that forms a first capacitance with the wire. A second electrode forming a second capacitance whose relation to the first capacitance is known between the electrode and the electric wire, and one end electrically connected to the first electrode A voltage applying means for applying to the other end of the resistor an applied voltage obtained by shifting the phase of the induced voltage generated in the second electrode by the AC voltage of the wire; and the AC voltage of the wire; Voltage separating means for separating the voltage generated in the first electrode by the applied voltage from the mixed voltage generated in the first electrode by the applied voltage by referring to the induced voltage; and the applied voltage Caused in the first electrode by the applied voltage The first capacitance is obtained based on the pressure, the second capacitance is obtained from the first capacitance using the known relationship, and the second capacitance and the induction are obtained. And an arithmetic means for obtaining an AC voltage of the electric wire based on the voltage.

  According to said structure, in the state by which the 1st and 2nd electrode was opposingly arranged by the electric wire, the 1st electrostatic capacity produced between a 1st electrode and an electric wire, a 2nd electrode, and an electric wire The second capacitance generated between the two and the second capacitor has a known relationship. For this purpose, the first and second electrodes are manufactured so that the above-described known relationship occurs.

  The voltage applying means applies an applied voltage obtained by shifting the phase of the induced voltage induced in the second electrode by the AC voltage of the electric wire to the other end of the resistor whose one end is electrically connected to the first electrode. . The voltage separation means refers to the voltage generated in the first electrode by the applied voltage and the induced voltage of the second electrode from the mixed voltage generated in the first electrode by the AC voltage of the electric wire and the applied voltage. To separate. The calculation means obtains the first capacitance based on the separated voltage generated in the first electrode by the applied voltage and the applied voltage. Next, the second capacitance is obtained from the obtained first capacitance using a known relationship between the first capacitance and the second capacitance. Further, the AC voltage of the electric wire is obtained based on the obtained second capacitance and the induced voltage of the second electrode.

  As described above, in the voltage measuring device, a voltage having the same frequency as that of the electric wire is supplied as an applied voltage from the second electrode to the first electrode, and the first electrode between the core of the electric wire and the first electrode is supplied. I'm looking for capacitance. Furthermore, the second capacitance is obtained by using a known relationship between the first capacitance and the second capacitance, and the voltage of the electric wire is obtained. Therefore, it is not affected by the difference in the relative dielectric constant of the insulation coating of the electric wire due to the difference in frequency, and the voltage of the electric wire can be accurately measured without being affected by changes in temperature and humidity.

  The voltage measurement method of the present invention is a voltage measurement method for measuring an AC voltage of an electric wire in a non-contact manner with a conductor constituting the electric wire, wherein a first capacitance is formed between the electric wire and the electric wire. A step of disposing an electrode, disposing a second electrode forming a second capacitance between the electric wire and the first electrostatic capacitance, and an AC voltage of the electric wire Applying a voltage applied to the other end of the resistor, one end of which is electrically connected to the first electrode, and an alternating current of the electric wire. A voltage separation step of separating a voltage generated in the first electrode by the applied voltage by referring to the induced voltage from a mixed voltage generated in the first electrode by the voltage and the applied voltage; and the application The first electrode according to the voltage and the applied voltage. The first capacitance is obtained based on the generated voltage, the second capacitance is obtained from the first capacitance using the known relationship, and the second capacitance A calculation step of obtaining an AC voltage of the electric wire based on the induced voltage.

  According to said structure, there exists an effect similar to the said voltage measuring device.

  The voltage measuring device of the present invention is a voltage measuring device that measures an AC voltage of a wire in a non-contact manner with a conductor constituting the wire, and a first capacitance that forms a first capacitance with the wire. A second electrode forming a second capacitance between the electrode and the electric wire; a resistor having one end electrically connected to the first electrode; and an AC voltage of the electric wire A voltage applying means for applying to the other end of the resistor an applied voltage obtained by shifting the phase of the second induced voltage generated in the electrode of the first electrode, and an AC voltage of the wire and the applied voltage generated on the first electrode. Voltage separating means for separating, from the mixed voltage, a first induced voltage generated by the AC voltage of the electric wire and a third induced voltage generated by the applied voltage by referring to the second induced voltage; Based on the applied voltage and the third induced voltage Calculating means for obtaining the first capacitance and obtaining an AC voltage of the electric wire based on the first capacitance and the first induced voltage or the second induced voltage. It is characterized by that.

  According to said structure, in the state by which the 1st and 2nd electrode was opposingly arranged by the electric wire, the 1st and 2nd electrode was respectively provided via the insulation coating by the voltage of the electric wire. Is induced. The voltage applying means applies an applied voltage obtained by shifting the phase of the second induced voltage generated in the second electrode by the AC voltage of the electric wire to the other end of the resistor whose one end is electrically connected to the first electrode. Apply. The voltage separating means includes a first induced voltage generated by the AC voltage of the electric wire and a third induced voltage generated by the applied voltage from the mixed voltage generated in the first electrode by the AC voltage of the electric wire and the applied voltage. Are separated by referring to the second induced voltage. The calculation means obtains a first capacitance based on the applied voltage and the third induced voltage, and based on the first capacitance and the first induced voltage or the second induced voltage, Find AC voltage.

  As described above, in the voltage measuring apparatus, a voltage having the same frequency as that of the electric wire is supplied as an applied voltage from the second electrode to the first electrode, and the capacitance between the core of the electric wire and the first electrode is supplied. The voltage of the electric wire is obtained. Therefore, it is not affected by the difference in the relative dielectric constant of the insulation coating of the electric wire due to the difference in frequency, and the voltage of the electric wire can be accurately measured without being affected by changes in temperature and humidity.

  The voltage measurement method of the present invention is a voltage measurement method for measuring an AC voltage of an electric wire in a non-contact manner with a conductor constituting the electric wire, and a step of disposing the first electrode and the second electrode opposite to the electric wire; And applying an applied voltage obtained by shifting the phase of the second induced voltage generated in the second electrode by the AC voltage of the electric wire to the other end of the resistor electrically connected to the first electrode at one end. From the voltage application step, the AC voltage of the electric wire and the mixed voltage generated in the first electrode by the applied voltage, the first induced voltage generated by the AC voltage of the electric wire and the third voltage generated by the applied voltage A voltage separation step of separating an induced voltage by referring to the second induced voltage; and determining the first capacitance based on the applied voltage and the third induced voltage; and Capacitance and the first induced current Or it is characterized in that it comprises a and a calculation step of obtaining an AC voltage of the electric wire based on said second induced voltage.

  According to said structure, there exists an effect similar to the said voltage measuring device.

  In the voltage measuring apparatus, the voltage applying means includes phase shift means for generating the applied voltage by causing the voltage applying means to shift the phase of the second induced voltage by 90 °, and the voltage separating means includes: First and second integrating means, wherein the first integrating means performs an integration operation so that only the third induced voltage remains from the mixed voltage, and the second integrating means comprises the mixed voltage The integration unit performs an integration operation so that only the first induced voltage remains, and the calculation unit obtains the first capacitance based on the applied voltage and the output voltage of the first integration unit, It is good also as a structure which calculates | requires the alternating voltage of the said electric wire based on the 1st electrostatic capacitance and the output voltage of the said 2nd integration means.

  According to said structure, the phase shift means of a voltage application means changes the phase of a 2nd induced voltage 90 degree | times, and produces | generates the said applied voltage. The first integration means of the voltage separation means performs an integration operation so that only the third induced voltage remains from the mixed voltage generated at the first electrode, and the second integration means of the voltage separation means The integration operation is performed so that only the first induced voltage remains from the mixed voltage generated at the electrode. The calculating means obtains a first capacitance formed between the electric wire and the first electrode based on the applied voltage and the output voltage of the first integrating means. Furthermore, the calculation means obtains the AC voltage of the electric wire based on the first capacitance and the output voltage of the second integration means.

  Therefore, the voltage of the electric wire can be easily and accurately obtained with a simple configuration.

  In the voltage measuring apparatus, the voltage applying means includes phase shift means for generating the applied voltage by causing the phase of the second induced voltage to shift by 90 °, and the voltage separating means includes first and second voltage separators. Peak voltage acquisition means, wherein the first peak voltage acquisition means acquires and outputs the peak voltage of the first induced voltage from the mixed voltage, and the second peak voltage acquisition means includes the mixed voltage. The calculation means obtains the first capacitance based on the applied voltage and the output voltage of the second peak voltage acquisition means. The AC voltage of the electric wire may be obtained based on the first capacitance and the output voltage of the first peak voltage acquisition means.

  According to said structure, the phase shift means of a voltage application means changes the phase of a 2nd induced voltage 90 degree | times, and produces | generates the said applied voltage. The first peak voltage acquisition means of the voltage separation means acquires and outputs the peak voltage of the first induced voltage from the mixed voltage generated at the first electrode, and the second peak voltage acquisition means of the voltage separation means is The peak voltage of the third induced voltage is acquired from the mixed voltage generated at the first electrode and output. The calculation means obtains a first capacitance formed between the electric wire and the first electrode based on the applied voltage and the output voltage of the second peak voltage acquisition means. Further, the calculation means obtains the AC voltage of the electric wire based on the first capacitance and the output voltage of the first peak voltage acquisition means.

  Therefore, the voltage of the electric wire can be easily and accurately obtained with a simple configuration.

  In the voltage measuring apparatus, the voltage applying unit includes a phase adjusting unit that shifts the phase of the applied voltage supplied to the first electrode so as to coincide with the phase of the second induced voltage, The voltage separating means includes subtracting means for subtracting the second induced voltage from the mixed voltage and outputting the third induced voltage, and the computing means includes the applied voltage and the output voltage of the subtracting means. It is good also as a structure which calculates | requires said 1st electrostatic capacitance based on 1st, and calculates | requires the alternating voltage of the said electric wire based on said 1st electrostatic capacitance and said 2nd induced voltage.

  According to said structure, the phase adjustment means of a voltage application means is changed so that the phase of the said applied voltage supplied to a 1st electrode may correspond with the phase of a 2nd induced voltage. The subtracting means of the voltage separating means subtracts the second induced voltage, that is, the first induced voltage from the voltage of the first electrode, and outputs a third induced voltage. The calculation means obtains a first capacitance formed between the electric wire and the first electrode based on the applied voltage and the output voltage of the subtraction means. Further, the calculation means obtains an AC voltage of the electric wire based on the first electrostatic capacity and the second induced voltage.

  Therefore, the voltage of the electric wire can be easily and accurately obtained with a simple configuration.

  According to the configuration of the present invention, it is not affected by the difference in the relative dielectric constant of the insulation coating of the wire due to the difference in frequency, and the voltage of the wire is accurately measured without being affected by changes in temperature and humidity. There is an effect that can be.

It is a block diagram which shows the structure of the voltage measuring device which measures the voltage of a measurement electric wire using the integration method in embodiment of this invention. It is explanatory drawing which shows the voltage waveform and phase of each part of the voltage measuring device shown in FIG. It is a circuit diagram which shows the equivalent circuit of the circuit G shown in FIG. It is a longitudinal cross-sectional view which shows the substantive example of the voltage measuring device shown in FIG. It is a perspective view of the detection unit shown in FIG. It is a block diagram which shows the structure of the voltage measurement apparatus which measures the voltage of a measurement electric wire using the peak hold method in other embodiment of this invention. It is explanatory drawing which shows the voltage waveform and phase of each part of the voltage measuring device shown in FIG. It is a block diagram which shows the structure of the voltage measuring device which measures the voltage of a measurement electric wire using the subtraction method in other embodiment of this invention. It is explanatory drawing which shows the voltage waveform and phase of each part of the voltage measuring device shown in FIG. It is a graph which shows the relationship between the measurement voltage of a measurement electric wire, time, and humidity. It is a graph which shows the relationship between the measurement voltage of a measurement electric wire, time, and temperature. It is a graph which shows the relationship between the dielectric constant and frequency characteristic of various insulating resin. It is a graph which shows the relationship between the dielectric constant of the insulation coating of a measurement wire, the frequency of the voltage of a measurement wire, and the impedance measurement frequency in the prior art.

[Embodiment 1]
Embodiments of the present invention will be described below with reference to the drawings. In the voltage measuring apparatus 1 of this Embodiment, the integration method is used for the process of the signal for calculating | requiring the voltage of the measurement electric wire 11. FIG.

(Configuration of voltage measuring device 1)
FIG. 1 is a block diagram illustrating a configuration of a voltage measuring apparatus 1 that measures a measurement voltage (alternating voltage) VL using an integration method. As shown in FIG. 1, the voltage measuring device 1 measures the voltage of a measuring wire (electric wire) 11 that is a covered electric wire to be subjected to voltage measurement.

  For this purpose, the voltage measuring apparatus 1 includes a first electrode (first electrode) 21, a second electrode (second electrode) 22, a first resistor R1, a second resistor R2, a first buffer 23, and a second buffer. 24, a first integration circuit (first integration means, voltage separation means) 25, a second integration circuit (second integration means, voltage separation means) 26, a phase shift circuit (phase shift means, voltage application means) 27, A first comparator 28, a second comparator 29, and a calculation unit (calculation means) 30 are provided.

  The 1st electrode 21 has a function as a probe for applying a voltage to the measurement electric wire 11, and detecting the voltage according to the voltage of the measurement electric wire 11, ie, the voltage according to the measurement voltage VL. Note that the coupling capacitance (first capacitance) between the core of the measuring wire 11 and the first electrode 21 is Cs.

  The first electrode 21 is connected to the output part of the phase shift circuit 27 via the first resistor R1. The first electrode 21 is connected to the input unit of the first buffer 23, and the output unit of the first buffer 23 is connected to the input unit of the first integration circuit 25 and the input unit of the second integration circuit 26. . The output units of the first and second integration circuits 25 and 26 are connected to the input unit of the calculation unit 30.

  The second electrode 22 has a function as a probe for detecting a voltage corresponding to the measurement voltage VL of the measurement wire 11. The coupling capacitance (second capacitance) between the core wire of the measurement wire 11 and the second electrode 22 is Cs, as in the case of the first electrode 21. In the present embodiment, the coupling capacities of the first electrode 21 and the second electrode 22 do not have to be the same, and a predetermined level of signal is applied to the first electrode 21 and the second electrode 22 due to the presence of the coupling capacitance. If it is obtained.

  The second electrode 22 is grounded via the second resistor R2. The second electrode 22 is connected to the input unit of the second buffer 24, and the output unit of the second buffer 24 is connected to the input unit of the second integration circuit 26 via the second comparator 29. The output unit of the second buffer 24 is connected to the input unit of the phase shift circuit 27. The output unit of the phase shift circuit 27 is connected to the input unit of the calculation unit 30. The output section of the phase shift circuit 27 is connected to the input section of the first integration circuit 26 via the first comparator 28. The first electrode 21 and the second electrode 22 are arranged around the measurement wire 11 so as to face the measurement wire 11.

  The phase shift circuit 27 shifts the phase of the voltage input from the second buffer 24 to generate a phase shift voltage (applied voltage, voltage Vin) 34, and the generated phase shift voltage 34 is used as the first comparator 28 and the calculation unit. Output to 30. In the present embodiment, the phase shift circuit 27 advances the phase of the input voltage by 90 °.

  Based on the voltage V1 output from the first integration circuit 25, the voltage V2 output from the second integration circuit 26, and the phase shift voltage 34 output from the phase shift circuit 27, the calculating unit 30 The voltage (measurement voltage VL) is calculated.

  The first comparator 28 and the second comparator 29 shape the input signals into rectangular waves and output them as COMP1 and COMP2, respectively.

  In the above configuration, the operation of the voltage measuring apparatus 1 will be described below. FIG. 2 is an explanatory diagram showing voltage waveforms and phases of each part of the voltage measuring apparatus 1 shown in FIG.

  When the first electrode 21 is arranged around the measurement electric wire 11, a signal corresponding to the measurement voltage VL is induced in the first electrode 21 by the coupling capacitance Cs between the core of the measurement electric wire 11 and the first electrode 21. The current Ix1 flows through the first resistor R1. As a result, a first induced voltage 31 (see FIG. 2C) is generated at both ends of the first resistor R1. The first induced voltage 31 has a phase advanced by 90 ° with respect to the phase of the measurement voltage VL by setting the first resistor R1 to a value sufficiently smaller than the impedance of the coupling capacitor Cs.

  When the second electrode 22 is arranged around the measurement electric wire 11, a signal corresponding to the measurement voltage VL is induced in the second electrode 22 by the coupling capacitance Cs between the core wire of the measurement electric wire 11 and the second electrode 22. The current Ix2 flows through the second resistor R2. Thereby, the 2nd induced voltage 32 (refer FIG. 1) arises in the both ends of 2nd resistance R2. As in the case of the first induced voltage 31, the second induced voltage 32 is set to a value sufficiently smaller than the impedance of the coupling capacitor Cs by setting the second resistor R2 to a value that is smaller than the phase of the measurement voltage VL. 90 ° advanced.

  The second induced voltage 32 is input to the phase shift circuit 27 via the second buffer 24. The phase shift circuit 27 outputs a phase shift voltage (applied voltage, voltage Vin) 34 having a phase advanced by approximately 180 ° with respect to the measurement voltage VL by advancing the phase of the input second induced voltage 32 by 90 °. To do.

  When the phase shift voltage 34 is applied to the first electrode 21 via the first resistor R1, the first electrode 21 has a coupling capacitance Cs between the first electrode 21 and the measuring wire 11 core. A signal corresponding to the phase shift voltage is induced, and a current Is flows through the first resistor R1. As a result, a third induced voltage 33 (see FIG. 2C) is generated at both ends of the first resistor R1. The third induced voltage 33 has substantially the same phase as the phase shift voltage by setting the first resistor R1 to a value sufficiently smaller than the impedance of the coupling capacitor Cs. That is, the phase of the third induced voltage 33 advances by approximately 180 ° with respect to the measurement voltage VL, and the phase advances by 90 ° with respect to the first induced voltage 31.

  Accordingly, the voltage at the point A on the input side of the first electrode 21, that is, the first buffer 23 (hereinafter referred to as the first electrode voltage) is equal to the first induced voltage 31 and the first induced voltage 31 as shown in FIG. 3 and the induced voltage 33 are mixed. The first electrode voltage is input to the first integration circuit 25 and the second integration circuit 26 via the first buffer 23.

  The phase shift voltage 34 output from the phase shift circuit 27 is input to the first integration circuit 25 as COMP <b> 1 through the first comparator 28. The second induced voltage 32 is input to the second integrating circuit 26 as COMP <b> 2 through the second buffer 24 and the second comparator 29. COMP1 and COMP2 are shown in FIGS. 2A and 2B, respectively.

  The first integrating circuit 25 integrates the first electrode voltage for the ON period of COMP1 to extract only the third induced voltage 33 from the first electrode voltage, and a voltage that is an integrated value of the third induced voltage 33. The value V1 is output to the calculation unit 30.

  The second integrating circuit 26 integrates the first electrode voltage for the period of ON of COMP2 to extract only the first induced voltage 31 from the first electrode voltage, and a voltage that is an integrated value of the first induced voltage 31. The value V2 is output to the calculation unit 30.

  Next, how to determine the voltage value V2 in the second integration circuit 26 and how to determine the voltage value V1 in the first integration circuit 25 will be described.

When the first electrode voltage ((c) in FIG. 2) is V11,
V11 = A · sin (ωt) + B · cos (ωt) (1)
A · sin (ωt): third induced voltage 33
B · cos (ωt): first induced voltage 31
It becomes.

  Here, in the first electrode voltage V11, the first induced voltage 31 is erased if the first electrode voltage V11 is integrated for the ON period of COMP1. Thereby, only the third induced voltage 33 can be extracted.

  Further, in the first electrode voltage V11, the third induced voltage 33 is erased by integrating the first electrode voltage V11 for the ON period of COMP2. As a result, only the first induced voltage 31 can be extracted.

  Therefore, V11 (first electrode voltage) is integrated from 0 to π as in the following equation (3) to obtain voltage V1, and V11 (first electrode voltage) is obtained as in the following equation (4). Is integrated to π / 2 to 3π / 2 to obtain the voltage V2. In this case, the voltages V1 and V2 have only amplitude.

  Next, how to calculate the measurement voltage VL in the calculation unit 30 will be described. When the circuit G of FIG. 1 is shown by an equivalent circuit, it is as shown in FIG. From FIG. 3, the voltage V1 is obtained by dividing the voltage Vin (applied voltage) by the coupling capacitor Cs and the first resistor R1.

  In Expression (5), when jωCs is applied to the denominator and numerator of the fractional part, Expression (6) is obtained.

  If the amplitude of V1 is calculated | required from Formula (6), it will become Formula (7).

  When Expression (7) is solved for the coupling capacitance Cs, Expression (8) is obtained.

  In Expression (8), since the right side is all known variables in the calculation unit 30, the coupling capacitance Cs can be calculated.

  Furthermore, Formula (9) is materialized regarding measurement voltage VL from voltage V2 calculated | required separately.

  Therefore, the measurement voltage VL can be obtained by substituting Cs in the equation (8) for Cs in the equation (9).

(Substantial form example of the voltage measuring device 1)
FIG. 4 is a longitudinal sectional view showing a substantial form of the voltage measuring apparatus 1, and FIG. 5 is a perspective view of the detection unit shown in FIG. The configurations shown in FIGS. 4 and 5 are the same for the voltage measuring devices of the other embodiments.

  As shown in FIG. 4, the voltage measuring apparatus 1 includes a detection unit 41 and a calculation unit 30. The detection unit 41 includes a housing part 42 that is separated into an upper housing part 43 and a lower housing part 44. The upper housing part 43 and the lower housing part 44 are connected by a hinge 45, and the upper housing part 43 can be opened and closed with respect to the lower housing part 44. A shield plate 46 is provided on the inner surface of the housing portion 42.

  The second electrode 22 is disposed on the upper surface portion of the lower housing portion 44, and the first electrode 21 is disposed on the lower surface portion of the upper housing portion 43 so as to face the second electrode 22. The first electrode 21 and the second electrode 22 are formed in a semi-cylindrical shape obtained by vertically dividing a cylinder. Therefore, when the upper housing portion 43 is closed with respect to the lower housing portion 44, a cylinder is formed by the first electrode 21 and the second electrode 22, and the first electrode 21 and the second electrode 22 are interposed between them. The measuring wire 11 can be arranged. In FIG. 4, reference numeral 12 denotes a core wire of the measurement electric wire 11, and reference numeral 13 denotes an insulation coating of the measurement electric wire 11.

  A detection circuit board 47 is disposed inside the lower housing part 44. The detection circuit board 47 is provided with circuits other than the first electrode 21, the second electrode 22, and the calculation unit 30 in the voltage measurement device 1 shown in FIG. 1. The detection circuit board 47 is connected to the calculation unit 30 disposed outside the housing unit 42 via a connector 48 provided in the lower housing unit 44 and a cable 49.

  The voltage measuring device 1 shown in FIGS. 1 and 4 uses one set when the measuring wire 11 is a single-layer two-wire. Moreover, when the measurement electric wire 11 is a three-phase three-wire, you may use 3 sets. This also applies to voltage measuring devices according to other embodiments described below.

  As described above, in the voltage measurement device 1, by applying a signal acquired from the measurement wire 11 by the second electrode 22, that is, a signal having the same voltage and frequency as the measurement wire 11, from the first electrode 21 to the measurement wire 11, The coupling capacitance Cs between the core wire 12 of the measurement electric wire 11 and the first electrode 21 is obtained, and the voltage of the measurement electric wire 11, that is, the measurement voltage VL is obtained. As a result, the measurement voltage VL can be accurately measured without being influenced by changes in temperature and humidity without being affected by the difference in relative dielectric constant of the insulation coating 13 of the measurement wire 11 due to the difference in frequency. it can.

[Embodiment 2]
Another embodiment of the present invention will be described below with reference to the drawings. In the voltage measuring apparatus 101 of the present embodiment, the peak hold method is used for processing a signal for obtaining the voltage (measured voltage VL) of the measuring wire 11. In addition, the same code | symbol is attached | subjected to the means which has the same function as the means shown to the said embodiment, and description is abbreviate | omitted.

(Configuration of Voltage Measuring Device 101)
FIG. 6 is a block diagram illustrating a configuration of the voltage measurement apparatus 101 that measures the measurement voltage VL using the peak hold method. As shown in FIG. 6, the voltage measuring apparatus 101 includes a first electrode 21, a second electrode 22, a first resistor R1, a second resistor R2, a first buffer 23, a second buffer 24, a phase shift circuit 27, a first A sample hold circuit (first peak voltage acquisition means, voltage separation means) 111, a second sample hold circuit (second peak voltage acquisition means, voltage separation means) 112 and a calculation unit (calculation means) 30 are provided.

  The first electrode 21 is connected to the output part of the phase shift circuit 27 via the first resistor R1. The first electrode 21 is connected to the input section of the first buffer 23, and the output section of the first buffer 23 is connected to the input sections of the first sample hold circuit 111 and the second sample hold circuit 112. Output units of the first sample hold circuit 111 and the second sample hold circuit 112 are connected to an input unit of the calculation unit 30.

  The second electrode 22 is grounded via the second resistor R2. The second electrode 22 is connected to the input section of the second buffer 24, and the output section of the second buffer 24 is connected to the input section of the second sample and hold circuit 112. The output unit of the second buffer 24 is connected to the input unit of the phase shift circuit 27. The output unit of the phase shift circuit 27 is connected to the input unit of the calculation unit 30 and the input unit of the first sample hold circuit 111.

  The phase shift circuit 27 advances the phase of the voltage input from the second buffer 24 by 90 ° to obtain a phase shift voltage (applied voltage). This phase shift voltage is input to the first sample hold circuit 111 and the calculation unit 30 as the voltage Vin.

  The calculation unit 30 includes a voltage V2 output from the first sample hold circuit 111, a voltage V1 output from the second sample hold circuit 112, and a phase shift voltage (voltage Vin, applied voltage) output from the phase shift circuit 27. Based on the above, the voltage (measurement voltage VL) of the measurement wire 11 is calculated. In addition, the coupling capacity between the core wire of the measurement electric wire 11 and the first electrode 21 and the second electrode 22 is similarly Cs. In the present embodiment, the coupling capacities of the first electrode 21 and the second electrode 22 do not have to be the same, and a predetermined level of signal is applied to the first electrode 21 and the second electrode 22 due to the presence of the coupling capacitance. If it is obtained.

  In the above configuration, the operation of the voltage measuring apparatus 101 will be described below. FIG. 7 is an explanatory diagram showing voltage waveforms and phases of each part of the voltage measuring apparatus 101 shown in FIG.

  When the first electrode 21 is arranged around the measurement electric wire 11, a signal corresponding to the measurement voltage VL is induced in the first electrode 21 by the coupling capacitance Cs between the core of the measurement electric wire 11 and the first electrode 21. The current Ix1 flows through the first resistor R1. As a result, a first induced voltage 31 (see FIG. 7C) is generated at both ends of the first resistor R1. The first induced voltage 31 has a phase advanced by 90 ° with respect to the phase of the measurement voltage VL by setting the first resistor R1 to a value sufficiently smaller than the impedance of the coupling capacitor Cs.

  When the second electrode 22 is arranged around the measurement electric wire 11, a signal corresponding to the measurement voltage VL is induced in the second electrode 22 by the coupling capacitance Cs between the core wire of the measurement electric wire 11 and the second electrode 22. The current Ix2 flows through the second resistor R2. As a result, a second induced voltage 32 (see (a1) in FIG. 7) is generated at both ends of the second resistor R2. As in the case of the first induced voltage 31, the second induced voltage 32 is set to a value sufficiently smaller than the impedance of the coupling capacitor Cs by setting the second resistor R2 to a value that is smaller than the phase of the measurement voltage VL. 90 ° advanced.

  The second induced voltage 32 is input to the input unit of the phase shift circuit 27 and the input unit of the second sample hold circuit 112 via the second buffer 24.

  The phase shift circuit 27 outputs a phase shift voltage (applied voltage, voltage Vin) 34 having a phase advanced by approximately 180 ° with respect to the measurement voltage VL by advancing the phase of the input second induced voltage 32 by 90 °. (Refer to (b1) in FIG. 7). This phase shift voltage 34 is input to the first sample hold circuit 111 and also input to the calculation unit 30 as the voltage Vin.

  When the phase shift voltage 34 is applied to the first electrode 21 via the first resistor R1, the phase shift is applied to the first electrode 21 due to the coupling capacitance Cs between the first electrode 21 and the core wire of the measuring wire 11. A signal corresponding to the voltage 34 is induced, and a current Is flows through the first resistor R1. As a result, a third induced voltage 33 (see FIG. 7C) is generated at both ends of the first resistor R1. The third induced voltage 33 has substantially the same phase as the phase shift voltage 34 by setting the first resistor R1 to a value sufficiently smaller than the impedance of the coupling capacitor Cs. Therefore, the phase of the third induced voltage 33 is advanced by approximately 180 ° with respect to the measurement voltage VL, and is advanced by 90 ° with respect to the first induced voltage 31.

  Accordingly, the voltage at the point A on the input side of the first electrode 21, that is, the first buffer 23 (first electrode voltage) is, as shown in FIG. 7C, the first induced voltage 31 and the third induced voltage. 33 is a mixed voltage. The first electrode voltage is input to the first sample hold circuit 111 and the second sample hold circuit 112 via the first buffer 23.

  The first sample hold circuit 111 generates a sample timing signal (see (b2) in FIG. 7) corresponding to the zero cross point of the phase shift voltage 34 from the phase shift voltage 34 ((b1) in FIG. 7). Further, the first sample hold circuit 111 samples the first electrode voltage ((c) in FIG. 7) with the generated sample timing signal. As a result, the first sample hold circuit 111 acquires the peak-to-peak voltage of the first induced voltage 31 and outputs the voltage to the calculator 30 as the voltage V2.

  Similarly, the second sample-and-hold circuit 112 receives a sample timing signal corresponding to the zero cross point of the second induced voltage 32 from the second induced voltage 32 ((a1) in FIG. 7) (see (a2) in FIG. 7). Is generated. Further, the second sample hold circuit 112 samples the first electrode voltage ((c) in FIG. 7) with the generated sample timing signal. As a result, the second sample and hold circuit 112 acquires the peak-to-peak voltage of the third induced voltage 33 and outputs the voltage to the calculator 30 as the voltage V1.

  Since the input voltage V1, V2, Vin is known in the calculation unit 30, the measured voltage VL is calculated from the voltages V1, V2, Vin and the above equations (5) to (9) as described above. Calculate

As described above, in the voltage measurement device 101, by applying a signal acquired from the measurement wire 11 by the second electrode 22, that is, a voltage having the same frequency as the voltage of the measurement wire 11, from the first electrode 21 to the measurement wire 11, The coupling capacitance Cs between the core wire 12 of the measurement electric wire 11 and the first electrode 21 is obtained, and the voltage of the measurement electric wire 11, that is, the measurement voltage VL is obtained. As a result, the measurement voltage VL can be accurately measured without being influenced by changes in temperature and humidity without being affected by the difference in relative dielectric constant of the insulation coating 13 of the measurement wire 11 due to the difference in frequency. it can.
[Embodiment 3]
Still another embodiment of the present invention will be described below with reference to the drawings. In the voltage measuring apparatus 102 of the present embodiment, the subtraction method is used for processing a signal for obtaining the voltage of the measuring wire 11 (measured voltage VL). In addition, the same code | symbol is attached | subjected to the means which has the same function as the means shown to the said embodiment, and description is abbreviate | omitted.

(Configuration of voltage measuring device 102)
FIG. 8 is a block diagram illustrating a configuration of the voltage measuring apparatus 102 that measures the measurement voltage VL using the subtraction method. As shown in FIG. 8, the voltage measuring apparatus 102 includes a first electrode 21, a second electrode 22, a first resistor R1, a second resistor R2, a first buffer 23, a second buffer 24, a phase adjustment circuit (phase adjustment means). , A voltage applying unit) 121, a subtracting circuit (subtracting unit, voltage separating unit) 122, and a calculating unit (calculating unit) 30. In the present embodiment, the coupling capacitance (first capacitance) between the core wire of the measurement electric wire 11 and the first electrode 21, and between the core wire of the measurement electric wire 11 and the second electrode 22. The coupling capacitance (second capacitance) is the same value Cs. Further, the first resistor R1 and the second resistor R2 have the same value.

  The first electrode 21 is connected to the output unit of the phase adjustment circuit 121 via the first resistor R1. The first electrode 21 is connected to the input unit of the first buffer 23, and the output unit of the first buffer 23 is connected to the input unit of the subtraction circuit 122. The output unit of the subtraction circuit 122 is connected to the input unit of the calculation unit 30.

  The second electrode 22 is grounded via the second resistor R2. The second electrode 22 is connected to an input unit of the second buffer 24, and an output unit of the second buffer 24 includes an input unit of the phase adjustment circuit 121, an input unit of the subtraction circuit 122, and an input unit of the calculation unit 30. It is connected.

  The phase adjustment circuit 121 adjusts the phase of the voltage input from the second buffer 24 so as to match the phase of the first induced voltage 31 (see FIG. 9B), and adjusts the phase-adjusted voltage (applied voltage). ) 51 (see FIG. 8). The phase adjusted voltage 51 is input to the calculation unit 30 as the voltage Vin.

  Note that the phase adjustment circuit 121 returns the original phase when the phase of the signal (second induced voltage 32) of the second electrode 22 is shifted in the path from the second electrode 22 to the output unit of the phase adjustment circuit 121. It adjusts so that it may return to this phase. The phase adjustment amount (phase shift amount) in the phase adjustment circuit 121 is adjusted and set, for example, when the voltage measurement device 102 is shipped from the factory.

  The subtraction circuit 122 outputs the third induced voltage 33 obtained by subtracting the second induced voltage 32 from the first electrode voltage of the first electrode 21 to the calculating unit 30 as the voltage V1.

  The calculation unit 30 is based on the voltage V1 output from the subtraction circuit 122, the voltage V2 output from the second buffer 24, and the first phase adjusted voltage (voltage Vin) 51 output from the phase adjustment circuit 121. The voltage of the measurement wire 11 (measurement voltage VL) is calculated.

  In the above configuration, the operation of the voltage measuring apparatus 102 will be described below. FIG. 9 is an explanatory diagram showing voltage waveforms and phases of each part of the voltage measuring apparatus 102 shown in FIG.

  When the first electrode 21 is arranged around the measurement electric wire 11, a signal corresponding to the measurement voltage VL is induced in the first electrode 21 by the coupling capacitance Cs between the core of the measurement electric wire 11 and the first electrode 21. The current Ix1 flows through the first resistor R1. As a result, a first induced voltage 31 (see FIG. 9B) is generated at both ends of the first resistor R1. The first induced voltage 31 is advanced by 90 ° with respect to the phase of the measurement voltage VL by setting the first resistor R1 to a value sufficiently smaller than the impedance of the coupling capacitor Cs.

  When the second electrode 22 is arranged around the measurement electric wire 11, a signal corresponding to the measurement voltage VL is induced in the second electrode 22 by the coupling capacitance Cs between the core wire of the measurement electric wire 11 and the second electrode 22. The current Ix2 flows through the second resistor R2. As a result, a second induced voltage 32 shown in FIG. 9A is generated at both ends of the second resistor R2. As in the case of the first electrode 21, the second induced voltage 32 is advanced by 90 ° with respect to the phase of the measurement voltage VL by setting the second resistance R2 to a value sufficiently smaller than the impedance of the coupling capacitor Cs. It will be a thing. In the present embodiment, since the coupling capacitances of the first electrode 21 and the second electrode 22 are the same, and the first resistance R1 and the second resistance R2 have the same value, The amplitude with the second induced voltage 32 is equal.

  The second induced voltage 32 is input to the input unit of the phase adjustment circuit 121 and the input unit of the subtraction circuit 122 via the second buffer 24. The second induced voltage 32 is input to the input unit of the calculation unit 30 as the voltage V2.

  When the phase of the second induced voltage 32 is deviated from the original phase of the second induced voltage 32 when induced by the second electrode 22, the phase adjustment circuit 121 matches the original phase. Adjust and output as phase adjusted voltage 51. The phase-adjusted voltage 51 is input to the calculation unit 30 as the voltage Vin.

  When the phase-adjusted voltage 51 is applied to the first electrode 21 via the first resistor R1, the phase is applied to the first electrode 21 due to the coupling capacitance Cs between the first electrode 21 and the core of the measuring wire 11. A signal corresponding to the adjusted voltage 51 is induced, and the current Is flows through the first resistor R1. As a result, a third induced voltage 33 (see FIG. 9B) is generated at both ends of the first resistor R1. The third induced voltage 33 has substantially the same phase as the phase-adjusted voltage 51 by setting the first resistor R1 to a value sufficiently smaller than the impedance of the coupling capacitor Cs, and the phase is substantially the same as the measured voltage VL. The phase advances by 90 ° and is almost in phase with the first induced voltage 31.

  Therefore, the voltage at the point A on the input side of the first electrode 21, that is, the first buffer 23 (first electrode voltage) is, as shown in FIG. 9B, the first induced voltage 31 and the third induced voltage. 33 is a mixed voltage. This first electrode voltage is input to the subtraction circuit 122 via the first buffer 23.

  The subtraction circuit 122 subtracts the second induced voltage 32 (the voltage equal to the first induced voltage 31 in FIG. 9A) from the first electrode voltage (FIG. 9B), thereby 9 is output, and the subtractor output voltage (third induced voltage 33) shown in FIG. 9C is output to the calculation unit 30 as the voltage V1.

  Since the input voltage V1, V2, Vin is known in the calculation unit 30, the measured voltage VL is calculated from the voltages V1, V2, Vin and the above equations (5) to (9) as described above. Calculate

  As described above, in the voltage measuring device 102, by applying a signal acquired from the measurement wire 11 by the second electrode 22, that is, a signal having the same voltage and frequency as the measurement wire 11, from the first electrode 21 to the measurement wire 11, The coupling capacitance Cs between the core wire 12 of the measurement electric wire 11 and the first electrode 21 is obtained, and the voltage of the measurement electric wire 11, that is, the measurement voltage VL is obtained. As a result, the measurement voltage VL can be accurately measured without being influenced by changes in temperature and humidity without being affected by the difference in relative dielectric constant of the insulation coating 13 of the measurement wire 11 due to the difference in frequency. it can.

  In the above embodiment, the first capacitance formed between the measurement electric wire 11 and the first electrode 21 and the second capacitance formed between the measurement electric wire 11 and the second electrode 22. Although the case where the capacitance is the same has been described, both capacitances may be different from each other. In this case, the first capacitance and the second capacitance have a known relationship. For this purpose, the first and second electrodes are manufactured so that the above-described known relationship occurs.

  In addition, the configuration of the voltage measuring device 1 in this case includes the first resistor R1 having one end electrically connected to the first electrode 21 in addition to the first electrode 21 and the second electrode 22, and the alternating current of the measuring wire 11. Voltage application means for applying an applied voltage, which is caused to shift the phase of the induced voltage generated in the second electrode 22 by the voltage, to the other end of the first resistor R1, and the first electrode 21 by the AC voltage of the measuring wire 11 and the applied voltage. Voltage separating means for separating the voltage generated in the first electrode 21 by the applied voltage by referring to the induced voltage, the applied voltage, and the applied voltage to the first electrode 21 by the applied voltage. A first capacitance is obtained based on the generated voltage, a second capacitance is obtained from the first capacitance using the known relationship, and the second capacitance and the induced voltage are obtained. Based on the AC voltage of the wire It can be configured to include a Mel calculating means.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can be used as an AC voltage measuring device such as a commercial power source supplied to various devices.

1 Voltage measuring device 11 Measuring wire (wire)
12 Core wires 13 Insulation coating 21 First electrode (first electrode)
22 Second electrode (second electrode)
23 1st buffer 24 2nd buffer 25 1st integration circuit (1st integration means, voltage separation means)
26 Second integration circuit (second integration means, voltage separation means)
27 Phase shift circuit (phase shift means, voltage application means)
28 1st comparator 29 2nd comparator 30 Calculation part (calculation means)
31 First induced voltage 32 Second induced voltage 33 Third induced voltage 34 Phase shift voltage (applied voltage)
41 detection unit 42 housing part 43 upper housing part 44 lower housing part 51 phase adjusted voltage 101 voltage measuring device 102 voltage measuring device 111 first sample hold circuit (first peak voltage obtaining means, voltage separating means)
112 Second sample hold circuit (second peak voltage acquisition means, voltage separation means)
121 Phase adjustment circuit (phase adjustment means, voltage separation means)
122 Subtraction circuit (subtraction means, voltage application means)

Claims (7)

A voltage measuring device that measures an AC voltage of a wire in a non-contact manner with a conductor constituting the wire,
A first electrode forming a first capacitance with the electric wire;
A second electrode that forms a second capacitance between the wire and a known relationship with the first capacitance;
A resistor having one end electrically connected to the first electrode;
Voltage application means for applying to the other end of the resistor an applied voltage obtained by shifting the phase of the induced voltage generated in the second electrode by the AC voltage of the wire;
Voltage separation means for separating the voltage generated in the first electrode by the applied voltage from the mixed voltage generated in the first electrode by the AC voltage of the wire and the applied voltage by referring to the induced voltage When,
The first capacitance is obtained based on the applied voltage and the voltage generated in the first electrode by the applied voltage, and the second capacitance is obtained from the first capacitance using the known relationship. Computing means for obtaining an AC voltage of the electric wire based on the second capacitance and the induced voltage;
A voltage measuring device comprising: A voltage measuring device that measures an AC voltage of a wire in a non-contact manner with a conductor constituting the wire,
A first electrode forming a first capacitance with the electric wire;
A second electrode forming a second capacitance with the electric wire;
A resistor having one end electrically connected to the first electrode;
Voltage application means for applying to the other end of the resistor an applied voltage obtained by shifting the phase of the second induced voltage generated in the second electrode by the AC voltage of the wire;
From the mixed voltage generated in the first electrode by the AC voltage of the wire and the applied voltage, the first induced voltage generated by the AC voltage of the wire and the third induced voltage generated by the applied voltage are Voltage separating means for separating by referring to the second induced voltage;
The first capacitance is obtained based on the applied voltage and the third induced voltage, and based on the first capacitance and the first induced voltage or the second induced voltage, the first capacitance is obtained. An arithmetic means for obtaining the AC voltage of the electric wire;
A voltage measuring device comprising: The voltage application means includes phase shift means for generating the applied voltage by causing the phase of the second induced voltage to shift by 90 °,
The voltage separating means comprises first and second integrating means;
The first integration means performs an integration operation so that only the third induced voltage remains from the mixed voltage,
The second integration means performs an integration operation so that only the first induced voltage remains from the mixed voltage,
The calculation means obtains the first capacitance based on the applied voltage and the output voltage of the first integration means, and the first capacitance and the output voltage of the second integration means Obtaining the AC voltage of the wire based on
The voltage measuring device according to claim 2, wherein The voltage application means includes phase shift means for generating the applied voltage by causing the phase of the second induced voltage to shift by 90 °,
The voltage separation means includes first and second peak voltage acquisition means,
The first peak voltage obtaining unit obtains and outputs the peak voltage of the first induced voltage from the mixed voltage,
The second peak voltage acquisition means acquires and outputs the peak voltage of the third induced voltage from the mixed voltage,
The calculation means obtains the first capacitance based on the applied voltage and the output voltage of the second peak voltage acquisition means, and the first capacitance and the first peak voltage acquisition means. Obtaining the AC voltage of the wire based on the output voltage of
The voltage measuring device according to claim 2 , wherein The voltage applying means includes phase adjusting means for making a transition so that the phase of the applied voltage supplied to the first electrode matches the phase of the second induced voltage,
The voltage separating means includes subtracting means for subtracting the second induced voltage from the mixed voltage and outputting the third induced voltage,
The computing means obtains the first capacitance based on the applied voltage and the output voltage of the subtracting means, and based on the first capacitance and the second induced voltage, Find AC voltage,
The voltage measuring device according to claim 2 , wherein A voltage measurement method for measuring an AC voltage of a wire in a non-contact manner with a conductor constituting the wire,
A first electrode that forms a first capacitance between the electric wire and a second capacitance that has a known relationship with the first capacitance between the electric wire and the electric wire. Disposing a second electrode to form
A voltage applying step of applying an applied voltage obtained by shifting the phase of the induced voltage generated in the second electrode by the AC voltage of the electric wire to the other end of the resistor electrically connected to the first electrode at one end; ,
A voltage separation step of separating a voltage generated in the first electrode by the applied voltage by referring to the induced voltage from a mixed voltage generated in the first electrode by the AC voltage of the wire and the applied voltage. When,
The first capacitance is obtained based on the applied voltage and the voltage generated in the first electrode by the applied voltage, and the second capacitance is obtained from the first capacitance using the known relationship. And calculating the AC voltage of the wire based on the second capacitance and the induced voltage;
A voltage measurement method comprising: A voltage measurement method for measuring an AC voltage of a wire in a non-contact manner with a conductor constituting the wire,
Arranging the first electrode and the second electrode opposite to the electric wire;
Voltage applied to the other end of the resistor, one end of which is electrically connected to the first electrode, by applying a phase shift of the second induced voltage generated in the second electrode by the AC voltage of the electric wire Applying step;
From the mixed voltage generated in the first electrode by the AC voltage of the wire and the applied voltage, the first induced voltage generated by the AC voltage of the wire and the third induced voltage generated by the applied voltage are A voltage separation step of separating by referring to the second induced voltage;
A first capacitance formed between the electric wire and the first electrode is obtained based on the applied voltage and the third induced voltage, and the first capacitance and the first capacitance are obtained. A calculation step of obtaining an AC voltage of the electric wire based on an induced voltage or the second induced voltage;
A voltage measurement method comprising:

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