WO2015178051A1 - Voltage measurement device and voltage measurement method - Google Patents

Voltage measurement device and voltage measurement method Download PDF

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Publication number
WO2015178051A1
WO2015178051A1 PCT/JP2015/054927 JP2015054927W WO2015178051A1 WO 2015178051 A1 WO2015178051 A1 WO 2015178051A1 JP 2015054927 W JP2015054927 W JP 2015054927W WO 2015178051 A1 WO2015178051 A1 WO 2015178051A1
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voltage
measurement
reference electrode
measurement electrode
electrode voltage
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PCT/JP2015/054927
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French (fr)
Japanese (ja)
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悟郎 川上
公平 冨田
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オムロン株式会社
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/16—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using capacitive devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof

Definitions

  • the present invention relates to a voltage measuring device and a voltage measuring method for measuring an alternating voltage applied to a conductor of an insulated wire.
  • Patent Documents 1 to 3 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.
  • 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.
  • 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.
  • the characteristics of each insulation coating of insulated wires vary greatly depending on temperature and humidity. For this reason, the measurement voltage of a measurement electric wire changes a lot with temperature and humidity.
  • the relative dielectric constant of the insulation coating of the measuring wire has frequency characteristics, and the frequency characteristics vary depending on the material of the insulation coating.
  • PVC polyvinyl chloride
  • a high-frequency signal (frequency is significantly different from the measurement voltage of the measurement wire (for example, frequency 60 Hz)
  • the impedance between the conductor of the measurement wire and the detection electrode is measured by applying a frequency of 6 kHz to the measurement wire, and the voltage (measurement voltage) of the conductor is obtained based on the impedance. For this reason, the voltage of a measurement electric wire cannot be measured correctly.
  • the coupling capacity between the conductor of the wire and the electrode is obtained from the input signal from the electrode arranged on the insulator of the wire, and the AC voltage is obtained based on the value of this coupling capacity.
  • a reference alternating current advanced by 90 ° with respect to the alternating voltage is detected through an insulator.
  • the dielectric loss current accompanying the dielectric loss of the insulator is detected through the insulator.
  • the phase difference between these reference AC current (reference AC voltage) and dielectric loss current (dielectric loss voltage) is obtained, and the dielectric loss tangent of the insulator is calculated from this phase difference.
  • the previously obtained AC voltage value is corrected based on the value of the dielectric loss tangent. Therefore, according to such a configuration of Patent Document 3, the above-described problem of the configurations of Patent Documents 1 and 2 can be avoided.
  • Patent Document 3 requires a circuit for obtaining a phase difference between two AC voltages (reference AC voltage and dielectric loss voltage) and obtaining a dielectric loss tangent from the obtained phase difference.
  • capacitance between the conductor of an electric wire and an electrode the two capacitors with a known capacity
  • an object of the present invention is to provide a voltage measuring device and a voltage measuring method capable of accurately measuring the voltage of a measuring wire as a measuring object with a simple configuration.
  • the voltage measuring device of the present invention is a voltage measuring device that measures an AC voltage of an electric wire through an insulating coating of the electric wire, and a measurement electrode and a reference electrode arranged around the insulating coating, A measurement electrode voltage acquisition circuit that acquires a measurement electrode voltage generated at the measurement electrode by the AC voltage, and a reference electrode voltage that is generated at the reference electrode by the AC voltage and is out of phase by a certain amount from the phase of the AC voltage.
  • a reference electrode voltage acquisition circuit for acquiring the reference electrode voltage, and a phase difference between the measurement electrode voltage and the reference electrode voltage to obtain a coupling capacitance between the core of the wire and the measurement electrode, and the obtained coupling capacitance and the measurement
  • an arithmetic unit for obtaining the AC voltage from the electrode voltage.
  • FIG. 2 is a circuit diagram including a measurement electrode voltage acquisition circuit and a reference electrode voltage acquisition circuit from the measurement wire in FIG. 1 to the preceding stage of both comparators. It is a wave form diagram which shows the relationship of the phase of measurement voltage VL, measurement electrode voltage V1, and reference electrode voltage V2 which were shown in FIG. 2 is a timing chart of a measurement electrode voltage V1, a reference electrode voltage V2, a comparator output signal COMP1, 2 and a phase difference signal Vpd shown in FIG. It is explanatory drawing which shows the relationship of the phase of the measurement voltage VL shown in FIG. 1, the measurement electrode voltage V1, and the reference electrode voltage V2.
  • FIG. 2 is a circuit diagram including a measurement electrode voltage acquisition circuit and a reference electrode voltage acquisition circuit from the measurement wire in FIG. 1 to the preceding stage of both comparators.
  • FIG. 6 is a circuit diagram showing another example of the measurement electrode voltage acquisition circuit and the reference electrode voltage acquisition circuit shown in FIG. 1. 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.
  • FIG. 1 is a circuit diagram showing a configuration of a voltage measuring apparatus 1 according to an embodiment of the present invention.
  • the voltage measuring device 1 measures an alternating voltage of a measuring wire (electric wire) 11 that is a covered electric wire to be subjected to voltage measurement.
  • the voltage measurement apparatus 1 includes a measurement electrode 21, a reference electrode 22, a calculation unit 23, and a circuit that supplies the measurement electrode voltage V1 and the phase difference signal Vpd to the calculation unit 23.
  • the measurement electrode 21 and the reference electrode 22 have an arc shape having a predetermined width in the direction of the measurement electric wire 11 so that the measurement electrode 21 and the reference electrode 22 can be arranged on the outer periphery of the measurement electric wire 11.
  • the shape of the measurement electrode 21 and the reference electrode 22 is not limited to this, For example, what is necessary is just the shape which can contact
  • the calculation unit 23 is connected to an output terminal of an XOR (exclusive OR, phase difference signal output circuit) 24.
  • XOR exclusive OR, phase difference signal output circuit
  • a resistor (resistor) R1 Between the measurement electrode 21 and the first input terminal 24a of the XOR 24, a resistor (resistor) R1, an operational amplifier 25 and a resistor R2, and a comparator (comparator, first pulse wave output circuit) 26 are provided in series. It has been.
  • the resistor R1, the operational amplifier (first operational amplifier) 25, and the resistor R2 constitute a measurement electrode voltage acquisition circuit 31.
  • the resistor R1 is connected to the inverting input terminal of the operational amplifier 25, and the resistor R2 is connected between the inverting input terminal and the output terminal of the operational amplifier 25.
  • the operational amplifier 25 has a non-inverting input terminal grounded and an output terminal connected to the inverting input terminal of the comparator 26.
  • the output terminal of the operational amplifier 25 is connected to the calculation unit 23, whereby the measurement electrode voltage V ⁇ b> 1 is input to the calculation unit 23.
  • the comparator 26 has a non-inverting input terminal grounded via the resistor R11 and an output terminal connected to the first input terminal 24a of the XOR 24.
  • An operational amplifier (second operational amplifier) 27, a resistor R0, and a comparator (comparator, second pulse wave output circuit) 28 are provided in series between the reference electrode 22 and the second input terminal 24b of the XOR 24. ing. Among these, the operational amplifier 27 and the resistor R 0 constitute a reference electrode voltage acquisition circuit 32.
  • the resistor R0 is connected between the inverting input terminal and the output terminal of the operational amplifier 27.
  • the operational amplifier 27 has a non-inverting input terminal grounded and an output terminal connected to the inverting input terminal of the comparator 28.
  • the comparator 28 has a non-inverting input terminal grounded via the resistor R12 and an output terminal connected to the second input terminal 24b of the XOR 24.
  • the power supply voltage Vcc is supplied to the first input terminal 24a of the XOR 24 through the resistor R13, and the power supply voltage Vcc is supplied to the second input terminal 24b of the XOR 24 through the resistor R14.
  • a phase difference signal Vpd is output from the XOR 24 to the calculator 23.
  • the comparators 26 and 28, the resistors R11 and R12, the XOR 24, and the calculation unit 23 constitute an arithmetic unit.
  • FIG. 2 is a circuit diagram including the measurement electrode voltage acquisition circuit 31 and the reference electrode voltage acquisition circuit 32 from the measurement wire 11 to the preceding stage of the comparators 26 and 28 in FIG.
  • the measurement electrode 21 and the reference electrode 22 are arranged on the outer peripheral surface of the insulation coating of the measurement wire 11.
  • the coupling capacitance between the core wire of the measurement electric wire 11 and the measurement electrode 21 is defined as a coupling capacitance CL1
  • the coupling capacitance between the core wire of the measurement electric wire 11 and the reference electrode 22 is defined as a coupling capacitance CL2.
  • the coupling capacitance CL1 and the coupling capacitance CL2 do not need to match.
  • the measurement electrode voltage V1 is obtained from the measurement electrode 21 and the reference electrode voltage V2 is obtained from the reference electrode 22 by arranging the measurement electrode 21 and the reference electrode 22 around the measurement electric wire 11.
  • the circuit on the measurement electrode 21 side including the measurement electrode voltage acquisition circuit 31 includes a coupling capacitor CL1 and a resistor R1 in series, and an inverting amplification including these coupling capacitor CL1, resistor R1, operational amplifier 25, and resistor R2. Circuit. Therefore, the measurement electrode voltage V1 is represented by the following formula (1).
  • the phase ⁇ of the measurement electrode voltage V1 is expressed by the following formula (2)
  • the amplitude (absolute value) of the measurement electrode voltage V1 is expressed by the following formula (3).
  • Equation (2) the phase ⁇ of the measurement electrode voltage V1 varies depending on the value of the coupling capacitance CL1. That is, the phase ⁇ of the measurement electrode voltage V1 is shifted from the phase of the measurement voltage VL that is the voltage of the measurement wire 11.
  • FIG. 3 shows the phase relationship of the measurement voltage VL, the measurement electrode voltage V1, and the reference electrode voltage V2.
  • FIG. 3 is a waveform diagram showing the phase relationship between the measurement voltage VL, the measurement electrode voltage V1, and the reference electrode voltage V2.
  • FIG. 4 is a timing chart of the measurement electrode voltage V1, the reference electrode voltage V2, the output signal COMP1 of the comparator 26, the output signal COMP2 of the comparator 28, and the phase difference signal Vpd output from the XOR 24.
  • phase difference ⁇ T (corresponding to the phase difference ⁇ ) between the measurement electrode voltage V1 and the reference electrode voltage V2.
  • the comparator 26 receives the measurement electrode voltage V1 and outputs a pulse wave output signal COMP1 to the XOR 24.
  • the comparator 28 receives the reference electrode voltage V2 and outputs the pulse wave output signal COMP2 to the XOR 24.
  • the output signal COMP1 is a signal in which the measurement electrode voltage is binarized at the zero cross point
  • the output signal COMP2 is a signal in which the reference electrode voltage is binarized at the zero cross point.
  • the rising level of these output signals COMP1 and COMP2 is the power supply voltage Vcc.
  • the XOR 24 receives the output signal COMP1 and the output signal COMP2, and generates a phase difference signal Vpd that is an exclusive OR of the output signals COMP1 and COMP2, and outputs the phase difference signal Vpd to the calculation unit 23.
  • the phase difference signal Vpd is a pulse signal including a pulse having a width (time ⁇ T) corresponding to the phase difference ⁇ between the measurement electrode voltage V1 and the reference electrode voltage V2.
  • the phase difference between the measurement voltage VL and the reference electrode voltage V2 is 90 °
  • the phase difference between the measurement electrode voltage V1 and the reference electrode voltage V2 is ⁇
  • the phase difference between the measurement voltage VL and the measurement electrode voltage V1 is 90 ° ⁇ . ⁇ . Therefore, referring to equation (4), the relationship among the phases of the measurement voltage VL, the measurement electrode voltage V1, and the reference electrode voltage V2 is arranged as shown in FIG.
  • the calculation unit 23 obtains the phase difference ⁇ from the phase difference signal Vpd input from the XOR 24 by the equation (5).
  • f is the frequency of the measurement voltage VL.
  • the calculation unit 23 obtains an unknown coupling capacitance CL1 from Expression (4) using the obtained phase difference ⁇ . Further, the calculation unit 23 obtains the measurement voltage VL using the obtained coupling capacitance CL1.
  • the phase of the measurement electrode voltage V1 is Equation (2)
  • the amplitude of the measurement electrode voltage V1 is Equation (3).
  • the calculation unit 23 performs A / D conversion on the measurement electrode voltage V1 input from the output terminal of the operational amplifier 25 to obtain the value of the measurement electrode voltage V1.
  • formula (3) is arranged for the measurement voltage VL
  • formula (6) is obtained.
  • the coupling capacitance CL1 and the measurement electrode voltage V1 are known. Therefore, the calculation unit 23 can calculate the measurement voltage VL from Expression (6).
  • the measurement electrode voltage acquisition circuit 31 acquires the reference electrode voltage V2 whose phase is deviated from the phase of the measurement voltage VL by a certain value (for example, 90 °). Further, the comparators 26 and 28 and the XOR 24 obtain the phase difference ⁇ between the measurement electrode voltage V1 obtained from the measurement electrode voltage acquisition circuit 31 and the reference electrode voltage V2. Next, the coupling capacitance CL1 generated between the core wire of the measurement wire 11 and the measurement electrode 21 is obtained from the obtained phase difference ⁇ . Further, the calculation unit 23 obtains the value of the measurement electrode voltage V ⁇ b> 1 input from the measurement electrode voltage acquisition circuit 31. Further, the calculation unit 23 obtains the measurement voltage VL from the known coupling capacitance CL1 and measurement electrode voltage V1.
  • a configuration for obtaining the dielectric loss tangent a configuration for applying a voltage to the electrode arranged on the outer peripheral surface of the measuring wire 11, a configuration for acquiring a voltage generated in the electrode by the voltage applied to the electrode, and a plurality of voltages generated in the electrode
  • separate are unnecessary. Therefore, the circuit configuration is simplified and the circuit board can be reduced in size. Thereby, the measurement voltage VL can be accurately measured with a simple configuration.
  • the measurement electrode 21 is arranged in contact with the outer peripheral surface of the insulation coating of the measurement electric wire 11, while the reference electrode 22 is not brought into contact with the outer peripheral surface of the measurement electric wire 11. It is preferably arranged in a floating state of 1 to 2 mm. That is, when the reference electrode 22 is floated from the surface of the insulation coating of the measurement electric wire 11 so that a space exists between the insulation coating and the reference electrode 22, the electricity between the insulation coating and the reference electrode 22 is Resistance becomes infinite. As a result, it is possible to prevent the phase of the reference electrode voltage V2 from changing due to a change in the resistance value of the surface of the insulating coating due to the influence of the environmental change. It becomes easy to fix the shift amount.
  • the voltage measuring apparatus 1 uses the operational amplifiers 25 and 27 and the XOR 24 in order to easily obtain the phase difference ⁇ , that is, ⁇ T from the measurement electrode voltage V1 and the reference electrode voltage V2.
  • the voltage measuring apparatus 1 includes the operational amplifiers 25 and 27 and the XOR 24, so that the burden on the CPU constituting the calculation unit 23 can be reduced and high-speed processing can be performed in order to obtain the phase difference ⁇ , that is, ⁇ T.
  • the calculation unit 23 can be configured by an inexpensive CPU instead of an expensive CPU.
  • the voltage measuring apparatus 1 does not include the operational amplifiers 25 and 27 and the XOR 24, and the calculation unit 23 performs A / D conversion on the measurement electrode voltage V1 and the reference electrode voltage V2 to measure the measurement electrode voltage V1 and the reference electrode voltage V2.
  • the phase difference ⁇ that is, ⁇ T may be calculated from the time difference between the zero cross points.
  • FIG. 6 is a circuit diagram showing another example of the measurement electrode voltage acquisition circuit 31 and the reference electrode voltage acquisition circuit 32 shown in FIG.
  • the operational amplifiers 25 and 27 are used as inverting amplifier circuits, whereas in the measurement electrode voltage acquisition circuit 41 shown in FIG. 6, the operational amplifiers 25 and 27 are not inverted. Used as an amplifier circuit. Even in such a circuit, the measurement electrode voltage V1 and the reference electrode voltage V2 can be obtained similarly.
  • the measurement electrode voltage V1 is expressed by the following equation (7).
  • the phase ⁇ of the measurement electrode voltage V1 is expressed by the following formula (8)
  • the amplitude (absolute value) of the measurement electrode voltage V1 is expressed by the following formula (9).
  • the equation (8) (provided that the phase difference between the phase of the measurement voltage VL and the phase of the reference electrode voltage V2 is 90 ° (the phase of the reference electrode voltage V2 is advanced by 90 °)).
  • the expression R21 is read as R22), and the value of the resistor R22 is set.
  • the value of the resistor R22 is set to a level that can be ignored (for example, about 1 M ⁇ ), and is set to tan ⁇ 1 ⁇ in Equation (8).
  • the resistance R21 is set to a large value (for example, the impedance of the coupling capacitance CL2 (for example, 300 to 500 M ⁇ )) Set to about 500 M ⁇ ).
  • increasing the resistance R1 increases the voltage at the point A (for example, a voltage about 1/2 of the measurement voltage VL is applied). For this reason, when the measurement voltage VL is high and the voltage at the point A exceeds the power supply voltage of the operational amplifier 25, this circuit is difficult to use.
  • FIG. 7 is a longitudinal sectional view showing a substantial form of the voltage measuring apparatus 1
  • FIG. 8 is a perspective view of the detection unit shown in FIG.
  • the voltage measurement device 1 includes a detection unit 141 and a calculation unit 23.
  • the detection unit 141 includes a housing part 142 separated into an upper housing part 143 and a lower housing part 144.
  • the upper housing part 143 and the lower housing part 144 are connected by a hinge 145, and the upper housing part 143 can be opened and closed with respect to the lower housing part 144.
  • a shield plate 146 is provided on the inner surface of the housing 142.
  • the reference electrode 22 is disposed on the upper surface portion of the lower housing portion 144, and the measurement electrode 21 is disposed on the lower surface portion of the upper housing portion 143 so as to face the reference electrode 22.
  • the measurement electrode 21 and the reference electrode 22 are formed in a semi-cylindrical shape obtained by vertically dividing a cylinder. Therefore, when the upper housing part 143 is closed with respect to the lower housing part 144, a cylinder is formed by the measurement electrode 21 and the reference electrode 22, and the first and second electrodes 21, 22 around the measurement electric wire 11. Can be placed.
  • reference numeral 12 denotes a core wire of the measurement electric wire 11
  • reference numeral 13 denotes an insulation coating of the measurement electric wire 11.
  • a detection circuit board 147 is arranged inside the lower housing part 144.
  • the detection circuit board 147 is provided with circuits other than the first and second electrodes 21 and 22 and the calculation unit 23 in the voltage measurement apparatus 1 shown in FIG.
  • the detection circuit board 147 is connected to the calculation unit 23 disposed outside the housing unit 142 via the connector 148 provided in the lower housing unit 144 and the cable 149.
  • the voltage measuring device 1 shown in FIGS. 1 and 7 is used in 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, three sets are used.
  • the voltage measuring device is a voltage measuring device that measures an AC voltage of an electric wire through an insulating coating of the electric wire, and is generated in the measuring electrode by the measurement electrode and the reference electrode arranged around the insulating coating and the AC voltage.
  • the measurement electrode voltage acquisition circuit acquires the measurement electrode voltage induced in the measurement electrode by the AC voltage of the electric wire.
  • the reference electrode voltage acquisition circuit acquires a reference electrode voltage that is induced in the reference electrode by the AC voltage of the electric wire and whose phase is shifted by a certain amount with respect to the phase of the AC voltage.
  • the calculation unit obtains the coupling capacity between the core wire of the electric wire and the measurement electrode from the phase difference between the measurement electrode voltage and the reference electrode voltage, and obtains the AC voltage based on the obtained coupling capacity and the measurement electrode voltage.
  • a configuration for acquiring a voltage generated in the electrode by a voltage applied to the electrode, a configuration for separating a plurality of voltages generated in the electrode, and the like become unnecessary. Thereby, a circuit structure becomes simple and a circuit board can be reduced in size. As a result, the voltage of the electric wire can be accurately measured with a simple configuration.
  • the reference electrode voltage acquisition circuit may acquire the reference electrode voltage whose phase is shifted by 90 ° with respect to the phase of the AC voltage.
  • the reference electrode voltage acquisition circuit acquires the reference electrode voltage whose phase is shifted by 90 ° with respect to the phase of the AC voltage, signal processing using the reference electrode voltage in the subsequent circuit is performed. It becomes easy. Further, the reference electrode voltage acquisition circuit can have a simple circuit configuration excluding elements such as resistors that affect the phase of the reference electrode voltage.
  • the measurement electrode voltage acquisition circuit is an inverting amplifier circuit that includes a first operational amplifier, and the measurement electrode is connected to an inverting input terminal of the first operational amplifier via a resistor.
  • the reference electrode voltage acquisition circuit may include a second operational amplifier, and the reference electrode may be an inverting amplifier circuit that is directly connected to an inverting input terminal of the second operational amplifier.
  • the measurement electrode voltage acquisition circuit and the reference electrode voltage acquisition circuit can have a simple configuration using an operational amplifier.
  • the calculation unit includes a first pulse wave output circuit that outputs a first pulse wave that is a signal obtained by binarizing the measurement electrode voltage at a zero cross point, and zero crossing the reference electrode voltage.
  • a second pulse wave output circuit that outputs a second pulse wave that is a signal binarized at a point; the measurement electrode voltage and the reference electrode voltage from the first pulse wave and the second pulse wave;
  • a phase difference signal output circuit that outputs a phase difference signal indicating a phase difference of the signal, a coupling capacitance between the core of the wire and the measurement electrode is obtained from the phase difference signal, and the obtained coupling capacitance and the measurement electrode voltage It is good also as a structure provided with the calculation part which calculates
  • the first pulse wave output circuit outputs the first pulse wave that is a signal obtained by binarizing the measurement electrode voltage at the zero cross point.
  • the second pulse wave output circuit outputs a second pulse wave that is a signal obtained by binarizing the reference electrode voltage at the zero cross point.
  • the phase difference signal output circuit outputs a phase difference signal indicating the phase difference between the measurement electrode voltage and the reference electrode voltage from the first pulse wave and the second pulse wave.
  • a calculation part calculates
  • the calculation unit since the calculation unit includes the first pulse wave output circuit, the second pulse wave output circuit, the phase difference signal output circuit, and the calculation unit, the calculation unit is configured by a relatively inexpensive CPU. In addition, a general-purpose inexpensive circuit other than the calculation unit can be configured. As a result, when the entire arithmetic unit is configured by a CPU, an expensive CPU capable of high-speed processing is required, and the arithmetic unit becomes an expensive configuration, whereas the arithmetic unit can be configured at a low price. .
  • the voltage measuring method of the present invention is a voltage measuring method for measuring an AC voltage of an electric wire through an insulating coating of the electric wire, wherein a measuring electrode is arranged around the insulating coating of the electric wire, and the measuring electrode generated at the measuring electrode by the AC voltage
  • a coupling capacitance between the core of the wire and the measurement electrode is obtained, and the obtained coupling capacitance And a calculation step of obtaining the AC voltage from the measurement electrode voltage.
  • the voltage of the wire to be measured can be accurately measured with a simple configuration, similar to the above voltage measuring device.
  • the reference electrode may be arranged so as not to contact the insulating coating of the electric wire and to have a space between the insulating coating.
  • the electrical resistance between the insulating coating and the reference electrode is infinite by arranging the reference electrode so as not to contact the insulating coating of the electric wire and having a space between the insulating coating and the insulating coating. Become big. Therefore, it is possible to prevent the phase of the reference electrode voltage from changing due to the resistance value of the surface of the insulation coating being affected by the environmental change, and the amount of deviation of the phase of the reference electrode voltage from the phase of the AC voltage of the wire It becomes easy to fix.
  • the present invention can be used as an AC voltage measuring device such as a commercial power source supplied to various devices.

Abstract

A voltage measurement device (1) is provided with a measurement-electrode-voltage acquisition circuit (31), a reference-electrode-voltage acquisition circuit (32), and a calculation unit for determining the capacitive coupling between a core wire of an electric wire (11) and a measurement electrode (21) from the phase difference between a measurement electrode voltage and a reference electrode voltage that has a phase that is offset by a certain amount from an AC voltage.

Description

電圧計測装置および電圧計測方法Voltage measuring device and voltage measuring method
　本発明は、絶縁被覆されている電線の導体に印加されている交流の電圧を計測する電圧計測装置および電圧計測方法に関する。 The present invention relates to a voltage measuring device and a voltage measuring method for measuring an alternating voltage applied to a conductor of an insulated wire.
　従来、特許文献１～３に示されているように、計測電極を絶縁電線の導体に接触させることなく、絶縁電線に印加されている電圧を計測する技術が知られている。 Conventionally, as disclosed in Patent Documents 1 to 3, 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.
　特許文献１，２に記載の構成は、絶縁電線の絶縁被覆の一部の表面を覆うことが可能な検出電極および検出電極を覆うシールド電極を備えた検出プローブと、所定の周波数の信号を出力する発振器とを用いている。具体的には、発振器から所定の周波数の信号を出力し、その信号を検出プローブの検出電極に供給し、検出電極と導体との間のインピーダンスを計測している。さらに、絶縁電線の導体に印加された電圧に起因して検出電極から流出する電流を計測し、この電流と上記インピーダンスとから導体に印加されている電圧を計測している。 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.
　ここで、絶縁電線（計測電線）の各絶縁被覆の特性は、温度および湿度によって大きく変化する。このため、計測電線の計測電圧は温度および湿度によって大幅に変化する。また、計測電線の絶縁被覆の比誘電率は周波数特性を有し、しかも周波数特性は、絶縁被覆の材質によって異なる。特に、絶縁被覆として多用されているＰＶＣ（ポリ塩化ビニル）は、周波数の違いに対する比誘電率の違いが顕著である。 Here, the characteristics of each insulation coating of insulated wires (measurement wires) vary greatly depending on temperature and humidity. For this reason, the measurement voltage of a measurement electric wire changes a lot with temperature and humidity. Moreover, the relative dielectric constant of the insulation coating of the measuring wire has frequency characteristics, and the frequency characteristics vary depending on the material of the insulation coating. 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.
　上記のような要因によって計測電線の計測電圧が大きく左右される状況下において、特許文献１，２に記載の構成では、計測電線の計測電圧（例えば周波数６０Ｈｚ）とは周波数が大きく異なる高周波信号（例えば周波数６ｋＨｚ）を計測電線に印加することにより、計測電線の導体と検出電極との間のインピーダンスを計測し、そのインピーダンスに基づいて、導体の電圧（計測電圧）を求めている。このため、計測電線の電圧を正確に計測することができない。 Under the circumstances where the measurement voltage of the measurement wire is greatly influenced by the factors as described above, in the configurations described in Patent Documents 1 and 2, a high-frequency signal (frequency is significantly different from the measurement voltage of the measurement wire (for example, frequency 60 Hz) For example, the impedance between the conductor of the measurement wire and the detection electrode is measured by applying a frequency of 6 kHz to the measurement wire, and the voltage (measurement voltage) of the conductor is obtained based on the impedance. For this reason, the voltage of a measurement electric wire cannot be measured correctly.
　一方、特許文献３に記載の構成では、電線の交流電圧を求め、基準交流電流と誘電損失電流との位相差から、電線を被覆する絶縁体の誘電正接を求め、この誘電正接の値により、先に求めた交流電圧を補正するようにしている。 On the other hand, in the configuration described in Patent Document 3, the AC voltage of the electric wire is obtained, and the dielectric loss tangent of the insulator covering the electric wire is obtained from the phase difference between the reference alternating current and the dielectric loss current. The AC voltage obtained previously is corrected.
　具体的には、電線の絶縁体に配した電極からの入力信号により、電線の導体と電極との間の結合容量を求め、この結合容量の値に基づき交流電圧を求めている。また、交流電圧に対して９０°進んだ基準交流電流を絶縁体を通して検出している。また、絶縁体の誘電損失に伴う誘電損失電流を絶縁体を通して検出している。次に、これら基準交流電流（基準交流電圧）と誘電損失電流（誘電損失電圧）との位相差を求め、この位相差から絶縁体の誘電正接を算出している。さらに、誘電正接の値に基づき、先に求めた交流電圧値を補正している。したがって、このような特許文献３の構成によれば、特許文献１，２の構成が有する上記問題を回避できるようになっている。 Specifically, the coupling capacity between the conductor of the wire and the electrode is obtained from the input signal from the electrode arranged on the insulator of the wire, and the AC voltage is obtained based on the value of this coupling capacity. Further, a reference alternating current advanced by 90 ° with respect to the alternating voltage is detected through an insulator. In addition, the dielectric loss current accompanying the dielectric loss of the insulator is detected through the insulator. Next, the phase difference between these reference AC current (reference AC voltage) and dielectric loss current (dielectric loss voltage) is obtained, and the dielectric loss tangent of the insulator is calculated from this phase difference. Further, the previously obtained AC voltage value is corrected based on the value of the dielectric loss tangent. Therefore, according to such a configuration of Patent Document 3, the above-described problem of the configurations of Patent Documents 1 and 2 can be avoided.
日本国公開特許公報「特開平１０－２０６４６８号公報（１９９８年８月７日公開）」Japanese Patent Publication “Japanese Patent Laid-Open No. 10-206468 (published on August 7, 1998)” 日本国公開特許公報「特開２００２－３６５３１５号公報（２００２年１２月１８日公開）」Japanese Patent Publication “Japanese Patent Laid-Open No. 2002-365315 (published on Dec. 18, 2002)” 日本国公開特許公報「特開２００４－１７７３１０号公報（２００４年６月２４日公開）」Japanese Patent Publication “Japanese Patent Laid-Open No. 2004-177310 (published on June 24, 2004)”
　しかしながら、特許文献３の構成では、二つの交流電圧（基準交流電圧、誘電損失電圧）の位相差を求め、求めた位相差から誘電正接を求める回路が必要となる。また、電線の導体と電極との間の結合容量を求めるために、容量が既知の２個のコンデンサ、およびこれらコンデンサを切り替えるスイッチを備えている。このため、回路構成が複雑になるという問題点を有している。 However, the configuration of Patent Document 3 requires a circuit for obtaining a phase difference between two AC voltages (reference AC voltage and dielectric loss voltage) and obtaining a dielectric loss tangent from the obtained phase difference. Moreover, in order to obtain | require the coupling capacity | capacitance between the conductor of an electric wire and an electrode, the two capacitors with a known capacity | capacitance and the switch which switches these capacitors are provided. For this reason, there is a problem that the circuit configuration becomes complicated.
　したがって、本発明は、簡単な構成により計測対象である計測電線の電圧を正確に計測することができる電圧計測装置および電圧計測方法の提供を目的としている。 Therefore, an object of the present invention is to provide a voltage measuring device and a voltage measuring method capable of accurately measuring the voltage of a measuring wire as a measuring object with a simple configuration.
　上記の課題を解決するために、本発明の電圧計測装置は、電線の交流電圧を電線の絶縁被覆を通して計測する電圧計測装置において、前記絶縁被覆の周りに配置される計測電極および基準電極と、前記交流電圧により前記計測電極に生じる計測電極電圧を取得する計測電極電圧取得回路と、前記交流電圧により前記基準電極に生じる、前記交流電圧の位相に対して位相が一定量ずれている基準電極電圧を取得する基準電極電圧取得回路と、前記計測電極電圧と前記基準電極電圧との位相差から、前記電線の心線と前記計測電極との間の結合容量を求め、求めた結合容量および前記計測電極電圧により前記交流電圧を求める演算部とを備えていることを特徴としている。 In order to solve the above problems, the voltage measuring device of the present invention is a voltage measuring device that measures an AC voltage of an electric wire through an insulating coating of the electric wire, and a measurement electrode and a reference electrode arranged around the insulating coating, A measurement electrode voltage acquisition circuit that acquires a measurement electrode voltage generated at the measurement electrode by the AC voltage, and a reference electrode voltage that is generated at the reference electrode by the AC voltage and is out of phase by a certain amount from the phase of the AC voltage. A reference electrode voltage acquisition circuit for acquiring the reference electrode voltage, and a phase difference between the measurement electrode voltage and the reference electrode voltage to obtain a coupling capacitance between the core of the wire and the measurement electrode, and the obtained coupling capacitance and the measurement And an arithmetic unit for obtaining the AC voltage from the electrode voltage.
　本発明の構成によれば、簡単な構成により計測対象である電線の電圧を正確に計測することができる。 According to the configuration of the present invention, it is possible to accurately measure the voltage of the wire to be measured with a simple configuration.
本発明の実施の形態の電圧計測装置の構成を示す回路図である。It is a circuit diagram which shows the structure of the voltage measuring device of embodiment of this invention. 図１における計測電線から両比較器の前段までの、計測電極電圧取得回路および基準電極電圧取得回路を含む回路図である。FIG. 2 is a circuit diagram including a measurement electrode voltage acquisition circuit and a reference electrode voltage acquisition circuit from the measurement wire in FIG. 1 to the preceding stage of both comparators. 図１に示した計測電圧ＶＬ、計測電極電圧Ｖ１および基準電極電圧Ｖ２の位相の関係を示す波形図である。It is a wave form diagram which shows the relationship of the phase of measurement voltage VL, measurement electrode voltage V1, and reference electrode voltage V2 which were shown in FIG. 図１に示した計測電極電圧Ｖ１、基準電極電圧Ｖ２、比較器の出力信号ＣＯＭＰ１，２および位相差信号Ｖｐｄのタイミングチャートである。2 is a timing chart of a measurement electrode voltage V1, a reference electrode voltage V2, a comparator output signal COMP1, 2 and a phase difference signal Vpd shown in FIG. 図１に示した計測電圧ＶＬと計測電極電圧Ｖ１と基準電極電圧Ｖ２との位相の関係を示す説明図である。It is explanatory drawing which shows the relationship of the phase of the measurement voltage VL shown in FIG. 1, the measurement electrode voltage V1, and the reference electrode voltage V2. 図１に示した計測電極電圧取得回路および基準電極電圧取得回路の他の例を示す回路図である。FIG. 6 is a circuit diagram showing another example of the measurement electrode voltage acquisition circuit and the reference electrode voltage acquisition circuit shown in FIG. 1. 図１に示した電圧計測装置の実体的な形態例を示す縦断面図である。It is a longitudinal cross-sectional view which shows the substantive example of the voltage measuring device shown in FIG. 図７に示した検出ユニットの斜視図である。It is a perspective view of the detection unit shown in FIG.
　本発明の実施の形態を図面に基づいて以下に説明する。図１は、本発明の実施の形態の電圧計測装置１の構成を示す回路図である。 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of a voltage measuring apparatus 1 according to an embodiment of the present invention.
　（電圧計測装置１の構成）
　電圧計測装置１は、電圧計測対象の被覆電線である計測電線（電線）１１の交流電圧を計測するものである。図１に示すように、電圧計測装置１は、計測電極２１、基準電極２２、計算部２３、および計算部２３へ計測電極電圧Ｖ１および位相差信号Ｖｐｄを供給する回路を備えている。計測電極２１および基準電極２２は計測電線１１の外周に配置できるように、計測電線１１の方向に所定幅を有する円弧形状となっている。なお、計測電極２１および基準電極２２の形状は、これに限定されず、例えば平板状など、計測電線１１に接することができる形状であればよい。 (Configuration of voltage measuring device 1)
The voltage measuring device 1 measures an alternating voltage of a measuring wire (electric wire) 11 that is a covered electric wire to be subjected to voltage measurement. As shown in FIG. 1, the voltage measurement apparatus 1 includes a measurement electrode 21, a reference electrode 22, a calculation unit 23, and a circuit that supplies the measurement electrode voltage V1 and the phase difference signal Vpd to the calculation unit 23. The measurement electrode 21 and the reference electrode 22 have an arc shape having a predetermined width in the direction of the measurement electric wire 11 so that the measurement electrode 21 and the reference electrode 22 can be arranged on the outer periphery of the measurement electric wire 11. In addition, the shape of the measurement electrode 21 and the reference electrode 22 is not limited to this, For example, what is necessary is just the shape which can contact | connect the measurement electric wire 11, such as flat form.
　計算部２３には、ＸＯＲ（排他的論理和、位相差信号出力回路）２４の出力端子が接続されている。計測電極２１とＸＯＲ２４の第１入力端子２４ａとの間には、抵抗（抵抗器）Ｒ１、演算増幅器２５および抵抗Ｒ２、並びに比較器（コンパレータ、第１のパルス波出力回路）２６が直列に設けられている。このうち、抵抗Ｒ１、演算増幅器（第１演算増幅器）２５および抵抗Ｒ２は計測電極電圧取得回路３１を構成している。 The calculation unit 23 is connected to an output terminal of an XOR (exclusive OR, phase difference signal output circuit) 24. Between the measurement electrode 21 and the first input terminal 24a of the XOR 24, a resistor (resistor) R1, an operational amplifier 25 and a resistor R2, and a comparator (comparator, first pulse wave output circuit) 26 are provided in series. It has been. Among these, the resistor R1, the operational amplifier (first operational amplifier) 25, and the resistor R2 constitute a measurement electrode voltage acquisition circuit 31.
　抵抗Ｒ１は、演算増幅器２５の反転入力端子に接続され、抵抗Ｒ２は、演算増幅器２５の反転入力端子と出力端子との間に接続されている。演算増幅器２５は、非反転入力端子が接地され、出力端子が比較器２６の反転入力端子に接続されている。また、演算増幅器２５の出力端子は計算部２３と接続され、これにより、計算部２３には計測電極電圧Ｖ１が入力されるようになっている。比較器２６は、非反転入力端子が抵抗Ｒ１１を介して接地され、出力端子がＸＯＲ２４の第１入力端子２４ａと接続されている。 The resistor R1 is connected to the inverting input terminal of the operational amplifier 25, and the resistor R2 is connected between the inverting input terminal and the output terminal of the operational amplifier 25. The operational amplifier 25 has a non-inverting input terminal grounded and an output terminal connected to the inverting input terminal of the comparator 26. In addition, the output terminal of the operational amplifier 25 is connected to the calculation unit 23, whereby the measurement electrode voltage V <b> 1 is input to the calculation unit 23. The comparator 26 has a non-inverting input terminal grounded via the resistor R11 and an output terminal connected to the first input terminal 24a of the XOR 24.
　基準電極２２とＸＯＲ２４の第２入力端子２４ｂとの間には、演算増幅器（第２演算増幅器）２７および抵抗Ｒ０、並びに比較器（コンパレータ、第２のパルス波出力回路）２８が直列に設けられている。このうち、演算増幅器２７および抵抗Ｒ０は、基準電極電圧取得回路３２を構成している。 An operational amplifier (second operational amplifier) 27, a resistor R0, and a comparator (comparator, second pulse wave output circuit) 28 are provided in series between the reference electrode 22 and the second input terminal 24b of the XOR 24. ing. Among these, the operational amplifier 27 and the resistor R 0 constitute a reference electrode voltage acquisition circuit 32.
　抵抗Ｒ０は、演算増幅器２７の反転入力端子と出力端子との間に接続されている。演算増幅器２７は、非反転入力端子が接地され、出力端子が比較器２８の反転入力端子に接続されている。比較器２８は、非反転入力端子が抵抗Ｒ１２を介して接地され、出力端子がＸＯＲ２４の第２入力端子２４ｂと接続されている。 The resistor R0 is connected between the inverting input terminal and the output terminal of the operational amplifier 27. The operational amplifier 27 has a non-inverting input terminal grounded and an output terminal connected to the inverting input terminal of the comparator 28. The comparator 28 has a non-inverting input terminal grounded via the resistor R12 and an output terminal connected to the second input terminal 24b of the XOR 24.
　ＸＯＲ２４の第１入力端子２４ａには抵抗Ｒ１３を介して電源電圧Ｖｃｃが供給され、ＸＯＲ２４の第２入力端子２４ｂには抵抗Ｒ１４を介して電源電圧Ｖｃｃが供給されている。ＸＯＲ２４から計算部２３へは位相差信号Ｖｐｄが出力される。上記比較器２６，２８、抵抗Ｒ１１，１２、ＸＯＲ２４および計算部２３は、演算部を構成している。 The power supply voltage Vcc is supplied to the first input terminal 24a of the XOR 24 through the resistor R13, and the power supply voltage Vcc is supplied to the second input terminal 24b of the XOR 24 through the resistor R14. A phase difference signal Vpd is output from the XOR 24 to the calculator 23. The comparators 26 and 28, the resistors R11 and R12, the XOR 24, and the calculation unit 23 constitute an arithmetic unit.
　（電圧計測装置１の動作）
　上記の構成において、電圧計測装置１の動作について以下に説明する。図２は、図１における計測電線１１から比較器２６，２８の前段までの、計測電極電圧取得回路３１および基準電極電圧取得回路３２を含む回路図である。 (Operation of voltage measuring device 1)
In the above configuration, the operation of the voltage measuring apparatus 1 will be described below. FIG. 2 is a circuit diagram including the measurement electrode voltage acquisition circuit 31 and the reference electrode voltage acquisition circuit 32 from the measurement wire 11 to the preceding stage of the comparators 26 and 28 in FIG.
　電圧計測装置１により計測電圧ＶＬを計測する場合には、計測電極２１および基準電極２２を計測電線１１の絶縁被覆の外周面に配置する。この場合の計測電線１１の心線と計測電極２１との間の結合容量を結合容量ＣＬ１、計測電線１１の心線と基準電極２２との間の結合容量を結合容量ＣＬ２とする。なお、結合容量ＣＬ１と結合容量ＣＬ２とは一致している必要はない。 When measuring the measurement voltage VL with the voltage measurement device 1, the measurement electrode 21 and the reference electrode 22 are arranged on the outer peripheral surface of the insulation coating of the measurement wire 11. In this case, the coupling capacitance between the core wire of the measurement electric wire 11 and the measurement electrode 21 is defined as a coupling capacitance CL1, and the coupling capacitance between the core wire of the measurement electric wire 11 and the reference electrode 22 is defined as a coupling capacitance CL2. Note that the coupling capacitance CL1 and the coupling capacitance CL2 do not need to match.
　計測電線１１の周りに計測電極２１および基準電極２２を配置することにより、計測電極２１から計測電極電圧Ｖ１が得られ、基準電極２２から基準電極電圧Ｖ２が得られる。 The measurement electrode voltage V1 is obtained from the measurement electrode 21 and the reference electrode voltage V2 is obtained from the reference electrode 22 by arranging the measurement electrode 21 and the reference electrode 22 around the measurement electric wire 11.
　図２において、計測電極電圧取得回路３１を含む計測電極２１側の回路は、結合容量ＣＬ１と抵抗Ｒ１とが直列であり、これら結合容量ＣＬ１、抵抗Ｒ１、演算増幅器２５および抵抗Ｒ２を含む反転増幅回路である。したがって、計測電極電圧Ｖ１は、下記の式（１）のようになる。
Figure JPOXMLDOC01-appb-M000001
 　この場合、計測電極電圧Ｖ１の位相αは下記の式（２）となり、計測電極電圧Ｖ１の振幅（絶対値）は下記の式（３）となる。
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000003
 　式（２）から分かるように、計測電極電圧Ｖ１の位相αは、結合容量ＣＬ１の値によって変化する。すなわち、計測電極電圧Ｖ１の位相αは、計測電線１１の電圧である計測電圧ＶＬの位相に対してずれた状態となる。 In FIG. 2, the circuit on the measurement electrode 21 side including the measurement electrode voltage acquisition circuit 31 includes a coupling capacitor CL1 and a resistor R1 in series, and an inverting amplification including these coupling capacitor CL1, resistor R1, operational amplifier 25, and resistor R2. Circuit. Therefore, the measurement electrode voltage V1 is represented by the following formula (1).
Figure JPOXMLDOC01-appb-M000001
 In this case, the phase α of the measurement electrode voltage V1 is expressed by the following formula (2), and the amplitude (absolute value) of the measurement electrode voltage V1 is expressed by the following formula (3).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000003
 As can be seen from Equation (2), the phase α of the measurement electrode voltage V1 varies depending on the value of the coupling capacitance CL1. That is, the phase α of the measurement electrode voltage V1 is shifted from the phase of the measurement voltage VL that is the voltage of the measurement wire 11.
　一方、基準電極電圧取得回路４２を含む基準電極２２側の回路には、抵抗Ｒ１に相当する抵抗Ｒが存在しない。したがって、基準電極電圧Ｖ２の位相βは、式（２）において抵抗Ｒ１＝０であるから、ｔａｎ－１∞となり、９０°に漸近する。これにより、基準電極電圧Ｖ２の位相βは、結合容量ＣＬ２の影響を受けず、計測電圧ＶＬの位相に対して９０°（一定量）進んだ状態に固定される。
　上記の計測電圧ＶＬ、計測電極電圧Ｖ１および基準電極電圧Ｖ２の位相の関係を示すと図３のようになる。図３は、計測電圧ＶＬ、計測電極電圧Ｖ１および基準電極電圧Ｖ２の位相の関係を示す波形図である。 On the other hand, the circuit on the reference electrode 22 side including the reference electrode voltage acquisition circuit 42 does not have the resistor R corresponding to the resistor R1. Therefore, the phase β of the reference electrode voltage V2 is tan −1 ∞ as the resistance R1 = 0 in the equation (2), and asymptotically approaches 90 °. As a result, the phase β of the reference electrode voltage V2 is not affected by the coupling capacitance CL2, and is fixed at a state advanced by 90 ° (a constant amount) with respect to the phase of the measurement voltage VL.
FIG. 3 shows the phase relationship of the measurement voltage VL, the measurement electrode voltage V1, and the reference electrode voltage V2. FIG. 3 is a waveform diagram showing the phase relationship between the measurement voltage VL, the measurement electrode voltage V1, and the reference electrode voltage V2.
　図３において、Δαは、計測電極電圧Ｖ１と基準電極電圧Ｖ２との位相差を示している。そこで、基準電極電圧Ｖ２の位相が計測電圧ＶＬの位相から９０°進んでいることを加味し、位相差Δαを結合容量ＣＬ１および抵抗Ｒ１によって表すと、式（４）のようになる。
Figure JPOXMLDOC01-appb-M000004
 　図４は、計測電極電圧Ｖ１、基準電極電圧Ｖ２、比較器２６の出力信号ＣＯＭＰ１、比較器２８の出力信号ＣＯＭＰ２およびＸＯＲ２４から出力される位相差信号Ｖｐｄのタイミングチャートである。 In FIG. 3, Δα represents the phase difference between the measurement electrode voltage V1 and the reference electrode voltage V2. Therefore, taking into account that the phase of the reference electrode voltage V2 is advanced by 90 ° from the phase of the measurement voltage VL, and expressing the phase difference Δα by the coupling capacitance CL1 and the resistor R1, the following equation (4) is obtained.
Figure JPOXMLDOC01-appb-M000004
 FIG. 4 is a timing chart of the measurement electrode voltage V1, the reference electrode voltage V2, the output signal COMP1 of the comparator 26, the output signal COMP2 of the comparator 28, and the phase difference signal Vpd output from the XOR 24.
　図４に示すように、計測電極電圧Ｖ１と基準電極電圧Ｖ２との間には、位相差ΔＴ（位相差Δαに相当）が存在する。比較器２６は、計測電極電圧Ｖ１が入力されることにより、パルス波の出力信号ＣＯＭＰ１をＸＯＲ２４へ出力する。同様に、比較器２８は、基準電極電圧Ｖ２が入力されることにより、パルス波の出力信号ＣＯＭＰ２をＸＯＲ２４へ出力する。 As shown in FIG. 4, there is a phase difference ΔT (corresponding to the phase difference Δα) between the measurement electrode voltage V1 and the reference electrode voltage V2. The comparator 26 receives the measurement electrode voltage V1 and outputs a pulse wave output signal COMP1 to the XOR 24. Similarly, the comparator 28 receives the reference electrode voltage V2 and outputs the pulse wave output signal COMP2 to the XOR 24.
　なお、出力信号ＣＯＭＰ１は、計測電極電圧がゼロクロス点で二値化された信号であり、出力信号ＣＯＭＰ２は、基準電極電圧がゼロクロス点で二値化された信号である。また、これら出力信号ＣＯＭＰ１，ＣＯＭＰ２における立ち上がりのレベルは、電源電圧Ｖｃｃである。 The output signal COMP1 is a signal in which the measurement electrode voltage is binarized at the zero cross point, and the output signal COMP2 is a signal in which the reference electrode voltage is binarized at the zero cross point. The rising level of these output signals COMP1 and COMP2 is the power supply voltage Vcc.
　ＸＯＲ２４は、出力信号ＣＯＭＰ１と出力信号ＣＯＭＰ２とが入力されることにより、これら出力信号ＣＯＭＰ１，ＣＯＭＰ２の排他的論理和である位相差信号Ｖｐｄを生成し、計算部２３へ出力する。位相差信号Ｖｐｄは、計測電極電圧Ｖ１と基準電極電圧Ｖ２との位相差Δαに相当する幅（時間ΔＴ）のパルスを含むパルス信号である。 The XOR 24 receives the output signal COMP1 and the output signal COMP2, and generates a phase difference signal Vpd that is an exclusive OR of the output signals COMP1 and COMP2, and outputs the phase difference signal Vpd to the calculation unit 23. The phase difference signal Vpd is a pulse signal including a pulse having a width (time ΔT) corresponding to the phase difference Δα between the measurement electrode voltage V1 and the reference electrode voltage V2.
　ここで、計測電圧ＶＬと基準電極電圧Ｖ２との位相差は９０°、計測電極電圧Ｖ１と基準電極電圧Ｖ２の位相差はΔα、計測電圧ＶＬと計測電極電圧Ｖ１との位相差は９０°－Δαである。したがって、式（４）を参照し、計測電圧ＶＬと計測電極電圧Ｖ１と基準電極電圧Ｖ２との位相の関係を整理すると、図５のようになる。 Here, the phase difference between the measurement voltage VL and the reference electrode voltage V2 is 90 °, the phase difference between the measurement electrode voltage V1 and the reference electrode voltage V2 is Δα, and the phase difference between the measurement voltage VL and the measurement electrode voltage V1 is 90 ° −. Δα. Therefore, referring to equation (4), the relationship among the phases of the measurement voltage VL, the measurement electrode voltage V1, and the reference electrode voltage V2 is arranged as shown in FIG.
　計算部２３は、まず、ＸＯＲ２４から入力された位相差信号Ｖｐｄから、式（５）によって位相差Δαを求める。なお、ｆは計測電圧ＶＬの周波数である。 First, the calculation unit 23 obtains the phase difference Δα from the phase difference signal Vpd input from the XOR 24 by the equation (5). Note that f is the frequency of the measurement voltage VL.
　　Δα＝ΔＴ×ｆ×３６０　……　（５）
　次に、計算部２３は、求めた位相差Δαを用いて、式（４）から、未知の結合容量ＣＬ１を求める。さらに、計算部２３は、求めた結合容量ＣＬ１を用いて、計測電圧ＶＬを求める。 Δα = ΔT × f × 360 (5)
Next, the calculation unit 23 obtains an unknown coupling capacitance CL1 from Expression (4) using the obtained phase difference Δα. Further, the calculation unit 23 obtains the measurement voltage VL using the obtained coupling capacitance CL1.
　この場合、計測電極電圧Ｖ１の位相は式（２）、計測電極電圧Ｖ１の振幅は式（３）である。また、計算部２３は、演算増幅器２５の出力端子から入力された計測電極電圧Ｖ１をＡ／Ｄ変換して、計測電極電圧Ｖ１の値を求める。 In this case, the phase of the measurement electrode voltage V1 is Equation (2), and the amplitude of the measurement electrode voltage V1 is Equation (3). Further, the calculation unit 23 performs A / D conversion on the measurement electrode voltage V1 input from the output terminal of the operational amplifier 25 to obtain the value of the measurement electrode voltage V1.
　また、式（３）を計測電圧ＶＬについて整理すると、式（６）になる。
Figure JPOXMLDOC01-appb-M000005
 　式（６）において、結合容量ＣＬ１および計測電極電圧Ｖ１は既知となっている。したがって、計算部２３は、式（６）から計測電圧ＶＬを算出することができる。 Further, when formula (3) is arranged for the measurement voltage VL, formula (6) is obtained.
Figure JPOXMLDOC01-appb-M000005
 In equation (6), the coupling capacitance CL1 and the measurement electrode voltage V1 are known. Therefore, the calculation unit 23 can calculate the measurement voltage VL from Expression (6).
　以上のように、電圧計測装置１では、計測電極電圧取得回路３１により計測電圧ＶＬの位相に対して位相が一定値（例えば９０°）ずれた基準電極電圧Ｖ２を取得している。また、比較器２６，２８およびＸＯＲ２４により、計測電極電圧取得回路３１から得られる計測電極電圧Ｖ１と基準電極電圧Ｖ２との位相差Δαを求めている。次に、求めた位相差Δαから計測電線１１の心線と計測電極２１との間に生じる結合容量ＣＬ１を求めている。また、計算部２３により、計測電極電圧取得回路３１から入力した計測電極電圧Ｖ１の値を求めている。さらに、計算部２３により、既知となった結合容量ＣＬ１および計測電極電圧Ｖ１から計測電圧ＶＬを求めている。 As described above, in the voltage measuring device 1, the measurement electrode voltage acquisition circuit 31 acquires the reference electrode voltage V2 whose phase is deviated from the phase of the measurement voltage VL by a certain value (for example, 90 °). Further, the comparators 26 and 28 and the XOR 24 obtain the phase difference Δα between the measurement electrode voltage V1 obtained from the measurement electrode voltage acquisition circuit 31 and the reference electrode voltage V2. Next, the coupling capacitance CL1 generated between the core wire of the measurement wire 11 and the measurement electrode 21 is obtained from the obtained phase difference Δα. Further, the calculation unit 23 obtains the value of the measurement electrode voltage V <b> 1 input from the measurement electrode voltage acquisition circuit 31. Further, the calculation unit 23 obtains the measurement voltage VL from the known coupling capacitance CL1 and measurement electrode voltage V1.
　したがって、誘電正接を求める構成、計測電線１１の外周面に配置した電極に電圧を与える構成、前記電極に与えた電圧によって前記電極に生じる電圧を取得する構成、並びに前記電極に生じた複数の電圧を分離する構成等が不要となっている。したがって、回路構成が簡素となり、回路基板を小型化することができる。これにより、簡単な構成にて計測電圧ＶＬを正確に計測することができる。 Therefore, a configuration for obtaining the dielectric loss tangent, a configuration for applying a voltage to the electrode arranged on the outer peripheral surface of the measuring wire 11, a configuration for acquiring a voltage generated in the electrode by the voltage applied to the electrode, and a plurality of voltages generated in the electrode The structure etc. which isolate | separate are unnecessary. Therefore, the circuit configuration is simplified and the circuit board can be reduced in size. Thereby, the measurement voltage VL can be accurately measured with a simple configuration.
　なお、電圧計測装置１では、計測電極２１は計測電線１１の絶縁被覆の外周面に接触させて配置する一方、基準電極２２は、計測電線１１の外周面に接触させず、計測電線１１から例えば１～２ｍｍ浮いた状態に配置されることが好ましい。すなわち、計測電線１１の絶縁被覆の表面から基準電極２２を浮かせて、絶縁被覆と基準電極２２との間に空間が存在するようにした場合には、絶縁被覆と基準電極２２との間の電気抵抗が無限大となる。これにより、絶縁被覆の表面の抵抗値が環境の変化の影響を受けて変化することにより基準電極電圧Ｖ２の位相が変化することを防止し、計測電圧ＶＬの位相に対する基準電極電圧Ｖ２の位相のずれ量を固定し易くなる。 In the voltage measuring device 1, the measurement electrode 21 is arranged in contact with the outer peripheral surface of the insulation coating of the measurement electric wire 11, while the reference electrode 22 is not brought into contact with the outer peripheral surface of the measurement electric wire 11. It is preferably arranged in a floating state of 1 to 2 mm. That is, when the reference electrode 22 is floated from the surface of the insulation coating of the measurement electric wire 11 so that a space exists between the insulation coating and the reference electrode 22, the electricity between the insulation coating and the reference electrode 22 is Resistance becomes infinite. As a result, it is possible to prevent the phase of the reference electrode voltage V2 from changing due to a change in the resistance value of the surface of the insulating coating due to the influence of the environmental change. It becomes easy to fix the shift amount.
　また、電圧計測装置１では、計測電極電圧Ｖ１および基準電極電圧Ｖ２から、位相差ΔαすなわちΔＴを容易に求めるために、演算増幅器２５，２７およびＸＯＲ２４を使用している。すなわち、電圧計測装置１では、演算増幅器２５，２７およびＸＯＲ２４を備えていることにより、位相差ΔαすなわちΔＴを求めるために、計算部２３を構成するＣＰＵの負担を軽減し、高速処理が可能かつ高価なＣＰＵではなく、廉価なＣＰＵにて計算部２３を構成可能としている。 The voltage measuring apparatus 1 uses the operational amplifiers 25 and 27 and the XOR 24 in order to easily obtain the phase difference Δα, that is, ΔT from the measurement electrode voltage V1 and the reference electrode voltage V2. In other words, the voltage measuring apparatus 1 includes the operational amplifiers 25 and 27 and the XOR 24, so that the burden on the CPU constituting the calculation unit 23 can be reduced and high-speed processing can be performed in order to obtain the phase difference Δα, that is, ΔT. The calculation unit 23 can be configured by an inexpensive CPU instead of an expensive CPU.
　一方、電圧計測装置１は、演算増幅器２５，２７およびＸＯＲ２４を備えず、計算部２３にて、計測電極電圧Ｖ１および基準電極電圧Ｖ２をＡ／Ｄ変換し、計測電極電圧Ｖ１と基準電極電圧Ｖ２とのゼロクロス点の時間差から、位相差ΔαすなわちΔＴを演算して求める構成としてもよい。 On the other hand, the voltage measuring apparatus 1 does not include the operational amplifiers 25 and 27 and the XOR 24, and the calculation unit 23 performs A / D conversion on the measurement electrode voltage V1 and the reference electrode voltage V2 to measure the measurement electrode voltage V1 and the reference electrode voltage V2. Alternatively, the phase difference Δα, that is, ΔT may be calculated from the time difference between the zero cross points.
　（変形例）
　電圧計測装置１において、計測電極２１から計測電極電圧Ｖ１を取得する計測電極電圧取得回路３１、および基準電極２２から基準電極電圧Ｖ２を取得する基準電極電圧取得回路３２は、それぞれ図６に示す計測電極電圧取得回路４１および基準電極電圧取得回路４２であってもよい。図６は、図１に示した計測電極電圧取得回路３１および基準電極電圧取得回路３２の他の例を示す回路図である。 (Modification)
In the voltage measuring apparatus 1, the measurement electrode voltage acquisition circuit 31 that acquires the measurement electrode voltage V1 from the measurement electrode 21 and the reference electrode voltage acquisition circuit 32 that acquires the reference electrode voltage V2 from the reference electrode 22 are shown in FIG. The electrode voltage acquisition circuit 41 and the reference electrode voltage acquisition circuit 42 may be used. FIG. 6 is a circuit diagram showing another example of the measurement electrode voltage acquisition circuit 31 and the reference electrode voltage acquisition circuit 32 shown in FIG.
　図１に示す計測電極電圧取得回路３１では、演算増幅器２５，２７を反転増幅回路として使用していたのに対し、図６に示す計測電極電圧取得回路４１では、演算増幅器２５，２７を非反転増幅回路として使用している。このような回路であっても、同様に、計測電極電圧Ｖ１および基準電極電圧Ｖ２を取得することができる。 In the measurement electrode voltage acquisition circuit 31 shown in FIG. 1, the operational amplifiers 25 and 27 are used as inverting amplifier circuits, whereas in the measurement electrode voltage acquisition circuit 41 shown in FIG. 6, the operational amplifiers 25 and 27 are not inverted. Used as an amplifier circuit. Even in such a circuit, the measurement electrode voltage V1 and the reference electrode voltage V2 can be obtained similarly.
　計測電極電圧取得回路４１において、計測電極電圧Ｖ１は、下記の式（７）のようになる。
Figure JPOXMLDOC01-appb-M000006
 　この場合、計測電極電圧Ｖ１の位相αは下記の式（８）となり、計測電極電圧Ｖ１の振幅（絶対値）は下記の式（９）となる。
Figure JPOXMLDOC01-appb-M000007
Figure JPOXMLDOC01-appb-M000008
 　基準電極電圧取得回路４２では、計測電圧ＶＬの位相と基準電極電圧Ｖ２の位相との位相差が９０°となる（基準電極電圧Ｖ２の位相が９０°進む）ように、式（８）（但し、式Ｒ２１はＲ２２と読み替える）において抵抗Ｒ２２の値を設定する。具体的には、結合容量ＣＬ２のインピーダンス（例えば３００～５００ＭΩ）に対して、抵抗Ｒ２２の値を無視できる程度（例えば１ＭΩ程度）に設定し、式（８）においてｔａｎ－１∞とする。 In the measurement electrode voltage acquisition circuit 41, the measurement electrode voltage V1 is expressed by the following equation (7).
Figure JPOXMLDOC01-appb-M000006
 In this case, the phase α of the measurement electrode voltage V1 is expressed by the following formula (8), and the amplitude (absolute value) of the measurement electrode voltage V1 is expressed by the following formula (9).
Figure JPOXMLDOC01-appb-M000007
Figure JPOXMLDOC01-appb-M000008
 In the reference electrode voltage acquisition circuit 42, the equation (8) (provided that the phase difference between the phase of the measurement voltage VL and the phase of the reference electrode voltage V2 is 90 ° (the phase of the reference electrode voltage V2 is advanced by 90 °)). The expression R21 is read as R22), and the value of the resistor R22 is set. Specifically, with respect to the impedance (for example, 300 to 500 MΩ) of the coupling capacitor CL2, the value of the resistor R22 is set to a level that can be ignored (for example, about 1 MΩ), and is set to tan −1 ∞ in Equation (8).
　一方、計測電極電圧取得回路４１では、結合容量ＣＬ１の値によって計測電極電圧Ｖ１の位相を変化させたいので、結合容量ＣＬ２のインピーダンス（例えば３００～５００ＭΩ）に対して、抵抗Ｒ２１を大きい値（例えば５００ＭΩ程度）に設定する。 On the other hand, since the measurement electrode voltage acquisition circuit 41 wants to change the phase of the measurement electrode voltage V1 according to the value of the coupling capacitance CL1, the resistance R21 is set to a large value (for example, the impedance of the coupling capacitance CL2 (for example, 300 to 500 MΩ)) Set to about 500 MΩ).
　但し、結合容量ＣＬ１は通常１０ＰＦ程度（＝３００ＭΩ程度）であるので、抵抗Ｒ１を大きくすると、Ａ点の電圧が高くなる（例えば、計測電圧ＶＬの１／２程度の電圧がかかる）。このため、計測電圧ＶＬが高く、Ａ点の電圧が演算増幅器２５の電源電圧を超える場合には、この回路は使用し難い。 However, since the coupling capacitance CL1 is normally about 10 PF (= about 300 MΩ), increasing the resistance R1 increases the voltage at the point A (for example, a voltage about 1/2 of the measurement voltage VL is applied). For this reason, when the measurement voltage VL is high and the voltage at the point A exceeds the power supply voltage of the operational amplifier 25, this circuit is difficult to use.
　（電圧計測装置１の実体的な形態例）
　図７は、電圧計測装置１の実体的な形態例を示す縦断面図、図８は図７に示した検出ユニットの斜視図である。 (Substantial form example of the voltage measuring device 1)
FIG. 7 is a longitudinal sectional view showing a substantial form of the voltage measuring apparatus 1, and FIG. 8 is a perspective view of the detection unit shown in FIG.
　図７に示すように、電圧計測装置１は、検出ユニット１４１と計算部２３とを備えている。検出ユニット１４１は、上筐体部１４３と下筐体部１４４とに分離された筐体部１４２を備えている。上筐体部１４３と下筐体部１４４とはヒンジ１４５によって連結され、上筐体部１４３は下筐体部１４４に対して開閉可能となっている。また、筐体部１４２の内面には、シールド板１４６が設けられている。 As shown in FIG. 7, the voltage measurement device 1 includes a detection unit 141 and a calculation unit 23. The detection unit 141 includes a housing part 142 separated into an upper housing part 143 and a lower housing part 144. The upper housing part 143 and the lower housing part 144 are connected by a hinge 145, and the upper housing part 143 can be opened and closed with respect to the lower housing part 144. A shield plate 146 is provided on the inner surface of the housing 142.
　下筐体部１４４の上面部には、基準電極２２が配置され、上筐体部１４３の下面部には、基準電極２２と対向して計測電極２１が配置されている。これら計測電極２１および基準電極２２は、円筒を縦割りした形状の半円筒形に形成されている。したがって、下筐体部１４４に対して上筐体部１４３を閉じた場合に、計測電極２１と基準電極２２とにより円筒が形成され、計測電線１１の周りに第１および第２電極２１，２２を配置できるようになっている。なお、図８において、符号１２は計測電線１１の心線、符号１３は計測電線１１の絶縁被覆を示している。 The reference electrode 22 is disposed on the upper surface portion of the lower housing portion 144, and the measurement electrode 21 is disposed on the lower surface portion of the upper housing portion 143 so as to face the reference electrode 22. The measurement electrode 21 and the reference electrode 22 are formed in a semi-cylindrical shape obtained by vertically dividing a cylinder. Therefore, when the upper housing part 143 is closed with respect to the lower housing part 144, a cylinder is formed by the measurement electrode 21 and the reference electrode 22, and the first and second electrodes 21, 22 around the measurement electric wire 11. Can be placed. In FIG. 8, 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.
　下筐体部１４４の内部には、検出回路基板１４７が配置されている。検出回路基板１４７には、図１に示した電圧計測装置１における第１および第２電極２１，２２および計算部２３以外の回路が設けられている。検出回路基板１４７は、下筐体部１４４に設けられたコネクタ１４８、およびケーブル１４９を介して筐体部１４２の外部に配置される計算部２３と接続されている。 A detection circuit board 147 is arranged inside the lower housing part 144. The detection circuit board 147 is provided with circuits other than the first and second electrodes 21 and 22 and the calculation unit 23 in the voltage measurement apparatus 1 shown in FIG. The detection circuit board 147 is connected to the calculation unit 23 disposed outside the housing unit 142 via the connector 148 provided in the lower housing unit 144 and the cable 149.
　なお、図１および図７に示した電圧計測装置１は、計測電線１１が単層２線の場合には１セット使用される。また、計測電線１１が三相３線の場合には３セット使用される。 The voltage measuring device 1 shown in FIGS. 1 and 7 is used in 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, three sets are used.
　〔まとめ〕
　本発明の電圧計測装置は、電線の交流電圧を電線の絶縁被覆を通して計測する電圧計測装置において、前記絶縁被覆の周りに配置される計測電極および基準電極と、前記交流電圧により前記計測電極に生じる計測電極電圧を取得する計測電極電圧取得回路と、前記交流電圧により前記基準電極に生じる、前記交流電圧の位相に対して位相が一定量ずれている基準電極電圧を取得する基準電極電圧取得回路と、前記計測電極電圧と前記基準電極電圧との位相差から、前記電線の心線と前記計測電極との間の結合容量を求め、求めた結合容量および前記計測電極電圧により前記交流電圧を求める演算部とを備えている構成である。 [Summary]
The voltage measuring device according to the present invention is a voltage measuring device that measures an AC voltage of an electric wire through an insulating coating of the electric wire, and is generated in the measuring electrode by the measurement electrode and the reference electrode arranged around the insulating coating and the AC voltage. A measurement electrode voltage acquisition circuit for acquiring a measurement electrode voltage, and a reference electrode voltage acquisition circuit for acquiring a reference electrode voltage generated in the reference electrode by the AC voltage and having a phase shifted by a certain amount with respect to the phase of the AC voltage; The calculation of obtaining the coupling capacity between the core wire of the wire and the measurement electrode from the phase difference between the measurement electrode voltage and the reference electrode voltage, and obtaining the AC voltage from the obtained coupling capacity and the measurement electrode voltage. Part.
　上記の構成によれば、計測電極電圧取得回路は、電線の交流電圧によって計測電極に誘起される計測電極電圧を取得する。基準電極電圧取得回路は、電線の交流電圧によって基準電極に誘起される、交流電圧の位相に対して位相が一定量ずれている基準電極電圧を取得する。演算部は、計測電極電圧と基準電極電圧との位相差から、電線の心線と計測電極との間の結合容量を求め、求めた結合容量および計測電極電圧により交流電圧を求める。 According to the above configuration, the measurement electrode voltage acquisition circuit acquires the measurement electrode voltage induced in the measurement electrode by the AC voltage of the electric wire. The reference electrode voltage acquisition circuit acquires a reference electrode voltage that is induced in the reference electrode by the AC voltage of the electric wire and whose phase is shifted by a certain amount with respect to the phase of the AC voltage. The calculation unit obtains the coupling capacity between the core wire of the electric wire and the measurement electrode from the phase difference between the measurement electrode voltage and the reference electrode voltage, and obtains the AC voltage based on the obtained coupling capacity and the measurement electrode voltage.
　したがって、電極に与えた電圧によって電極に生じる電圧を取得する構成、さらには電極に生じた複数の電圧を分離する構成等が不要となる。これにより、回路構成が簡素となり、回路基板を小型化することができる。この結果、簡単な構成にて電線の電圧を正確に計測することができる。 Therefore, a configuration for acquiring a voltage generated in the electrode by a voltage applied to the electrode, a configuration for separating a plurality of voltages generated in the electrode, and the like become unnecessary. Thereby, a circuit structure becomes simple and a circuit board can be reduced in size. As a result, the voltage of the electric wire can be accurately measured with a simple configuration.
　上記の電圧計測装置において、前記基準電極電圧取得回路は、前記交流電圧の位相に対して位相が９０°ずれている前記基準電極電圧を取得する構成としてもよい。 In the voltage measuring apparatus, the reference electrode voltage acquisition circuit may acquire the reference electrode voltage whose phase is shifted by 90 ° with respect to the phase of the AC voltage.
　上記の構成によれば、基準電極電圧取得回路は、交流電圧の位相に対して位相が９０°ずれている基準電極電圧を取得するので、後段の回路での基準電極電圧を使用する信号処理が容易となる。また、基準電極電圧取得回路は、抵抗など、基準電極電圧の位相に影響する素子を除いた簡単な回路構成とすることができる。 According to the above configuration, since the reference electrode voltage acquisition circuit acquires the reference electrode voltage whose phase is shifted by 90 ° with respect to the phase of the AC voltage, signal processing using the reference electrode voltage in the subsequent circuit is performed. It becomes easy. Further, the reference electrode voltage acquisition circuit can have a simple circuit configuration excluding elements such as resistors that affect the phase of the reference electrode voltage.
　上記の電圧計測装置において、前記計測電極電圧取得回路は、第１演算増幅器を備え、前記計測電極が抵抗器を介して前記第１演算増幅器の反転入力端子に接続されている反転増幅回路であり、前記基準電極電圧取得回路は、第２演算増幅器を備え、前記基準電極が前記第２演算増幅器の反転入力端子に直接接続されている反転増幅回路である構成としてもよい。 In the voltage measurement apparatus, the measurement electrode voltage acquisition circuit is an inverting amplifier circuit that includes a first operational amplifier, and the measurement electrode is connected to an inverting input terminal of the first operational amplifier via a resistor. The reference electrode voltage acquisition circuit may include a second operational amplifier, and the reference electrode may be an inverting amplifier circuit that is directly connected to an inverting input terminal of the second operational amplifier.
　上記の構成によれば、計測電極電圧取得回路および基準電極電圧取得回路は、演算増幅器を使用した簡単な構成とすることができる。 According to the above configuration, the measurement electrode voltage acquisition circuit and the reference electrode voltage acquisition circuit can have a simple configuration using an operational amplifier.
　上記の電圧計測装置において、前記演算部は、前記計測電極電圧をゼロクロス点で二値化した信号である第１のパルス波を出力する第１のパルス波出力回路と、前記基準電極電圧をゼロクロス点で二値化した信号である第２のパルス波を出力する第２のパルス波出力回路と、前記第１のパルス波および前記第２のパルス波から前記計測電極電圧と前記基準電極電圧との位相差を示す位相差信号を出力する位相差信号出力回路と、前記位相差信号から前記電線の心線と前記計測電極との間の結合容量を求め、求めた結合容量および前記計測電極電圧により交流電圧を求める計算部とを備えている構成としてもよい。 In the voltage measurement device, the calculation unit includes a first pulse wave output circuit that outputs a first pulse wave that is a signal obtained by binarizing the measurement electrode voltage at a zero cross point, and zero crossing the reference electrode voltage. A second pulse wave output circuit that outputs a second pulse wave that is a signal binarized at a point; the measurement electrode voltage and the reference electrode voltage from the first pulse wave and the second pulse wave; A phase difference signal output circuit that outputs a phase difference signal indicating a phase difference of the signal, a coupling capacitance between the core of the wire and the measurement electrode is obtained from the phase difference signal, and the obtained coupling capacitance and the measurement electrode voltage It is good also as a structure provided with the calculation part which calculates | requires alternating voltage by.
　上記の構成によれば、第１のパルス波出力回路は、計測電極電圧をゼロクロス点で二値化した信号である第１のパルス波を出力する。第２のパルス波出力回路は、基準電極電圧をゼロクロス点で二値化した信号である第２のパルス波を出力する。位相差信号出力回路は、第１のパルス波および第２のパルス波から計測電極電圧と基準電極電圧との位相差を示す位相差信号を出力する。計算部は、位相差信号から電線の心線と計測電極との間の結合容量を求め、求めた結合容量および計測電極電圧により交流電圧を求める。 According to the above configuration, the first pulse wave output circuit outputs the first pulse wave that is a signal obtained by binarizing the measurement electrode voltage at the zero cross point. The second pulse wave output circuit outputs a second pulse wave that is a signal obtained by binarizing the reference electrode voltage at the zero cross point. The phase difference signal output circuit outputs a phase difference signal indicating the phase difference between the measurement electrode voltage and the reference electrode voltage from the first pulse wave and the second pulse wave. A calculation part calculates | requires the coupling capacity between the core wire of an electric wire and a measurement electrode from a phase difference signal, and calculates | requires alternating voltage by the calculated | required coupling capacity and measurement electrode voltage.
　上記のように、演算部は、第１のパルス波出力回路、第２のパルス波出力回路、位相差信号出力回路および計算部を備えているので、計算部を比較的廉価なＣＰＵにて構成し、かつ計算部以外を汎用の廉価な回路にて構成することができる。これにより、演算部全体をＣＰＵにて構成する場合に高速処理が可能な高価なＣＰＵが必要となって演算部が高価な構成となるのに対し、演算部を廉価な構成とすることができる。 As described above, since the calculation unit includes the first pulse wave output circuit, the second pulse wave output circuit, the phase difference signal output circuit, and the calculation unit, the calculation unit is configured by a relatively inexpensive CPU. In addition, a general-purpose inexpensive circuit other than the calculation unit can be configured. As a result, when the entire arithmetic unit is configured by a CPU, an expensive CPU capable of high-speed processing is required, and the arithmetic unit becomes an expensive configuration, whereas the arithmetic unit can be configured at a low price. .
　本発明の電圧計測方法は、電線の交流電圧を電線の絶縁被覆を通して計測する電圧計測方法において、前記電線の絶縁被覆の周りに計測電極を配置し、前記交流電圧により前記計測電極に生じる計測電極電圧を取得する計測電極電圧取得工程と、前記電線の絶縁被覆の周りに基準電極を配置し、前記交流電圧により前記基準電極に生じる、前記交流電圧の位相に対して位相が一定量ずれている基準電極電圧を取得する基準電極電圧取得工程と、前記計測電極電圧と前記基準電極電圧との位相差から、前記電線の心線と前記計測電極との間の結合容量を求め、求めた結合容量および前記計測電極電圧により前記交流電圧を求める演算工程とを備えている構成である。 The voltage measuring method of the present invention is a voltage measuring method for measuring an AC voltage of an electric wire through an insulating coating of the electric wire, wherein a measuring electrode is arranged around the insulating coating of the electric wire, and the measuring electrode generated at the measuring electrode by the AC voltage A measurement electrode voltage acquisition step for acquiring a voltage, and a reference electrode is arranged around the insulation coating of the electric wire, and the phase is shifted by a certain amount with respect to the phase of the AC voltage generated in the reference electrode by the AC voltage. Based on a reference electrode voltage acquisition step for acquiring a reference electrode voltage, and a phase difference between the measurement electrode voltage and the reference electrode voltage, a coupling capacitance between the core of the wire and the measurement electrode is obtained, and the obtained coupling capacitance And a calculation step of obtaining the AC voltage from the measurement electrode voltage.
　上記の構成によれば、上記の電圧計測装置と同様に、簡単な構成により計測対象である電線の電圧を正確に計測することができる。 According to the above configuration, the voltage of the wire to be measured can be accurately measured with a simple configuration, similar to the above voltage measuring device.
　上記の電圧計測方法において、前記基準電極は、前記電線の絶縁被覆に対して接触せず、前記絶縁被覆との間に空間を有するように配置する構成としてもよい。 In the voltage measurement method described above, the reference electrode may be arranged so as not to contact the insulating coating of the electric wire and to have a space between the insulating coating.
　上記の構成によれば、基準電極を電線の絶縁被覆に対して接触せず、絶縁被覆との間に空間を有するように配置することにより、絶縁被覆と基準電極との間の電気抵抗が無限大となる。したがって、絶縁被覆の表面の抵抗値が環境の変化の影響を受けて変化することにより基準電極電圧の位相が変化する事態を防止し、電線の交流電圧の位相に対する基準電極電圧の位相のずれ量を固定し易くなる。 According to the above configuration, the electrical resistance between the insulating coating and the reference electrode is infinite by arranging the reference electrode so as not to contact the insulating coating of the electric wire and having a space between the insulating coating and the insulating coating. Become big. Therefore, it is possible to prevent the phase of the reference electrode voltage from changing due to the resistance value of the surface of the insulation coating being affected by the environmental change, and the amount of deviation of the phase of the reference electrode voltage from the phase of the AC voltage of the wire It becomes easy to fix.
　本発明は上述した実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、実施形態に開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。 The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope shown in the claims, and the present invention is also applied to an embodiment obtained by appropriately combining technical means disclosed in the embodiment. It is included in the technical scope of the invention.
　本発明は、各種機器に供給されている商用電源等の交流電圧の測定機器として利用することができる。 The present invention can be used as an AC voltage measuring device such as a commercial power source supplied to various devices.
　　１　　電圧計測装置
　１１　　計測電線
　２１　　計測電極
　２２　　基準電極
　２３　　計算部（演算部）
　２４　　ＸＯＲ（位相差信号出力回路、演算部）
　２５　　演算増幅器（第１演算増幅器）
　２６　　比較器（第１のパルス波出力回路、演算部）
　２７　　演算増幅器（第２演算増幅器）
　２８　　比較器（第２のパルス波出力回路、演算部）
　３１　　計測電極電圧取得回路
　３２　　基準電極電圧取得回路
　４１　　計測電極電圧取得回路
　４２　　基準電極電圧取得回路
ＣＬ１　　結合容量
ＣＬ２　　結合容量
　Ｒ０　　抵抗
　Ｒ１　　抵抗（抵抗器）
　Ｒ２　　抵抗
Ｒ１１　　抵抗（演算部）
Ｒ１２　　抵抗（演算部） DESCRIPTION OF SYMBOLS 1 Voltage measuring device 11 Measuring wire 21 Measuring electrode 22 Reference electrode 23 Calculation part (calculation part)
24 XOR (phase difference signal output circuit, arithmetic unit)
25 operational amplifier (first operational amplifier)
26 comparator (first pulse wave output circuit, arithmetic unit)
27 Operational amplifier (second operational amplifier)
28 comparator (second pulse wave output circuit, arithmetic unit)
31 measurement electrode voltage acquisition circuit 32 reference electrode voltage acquisition circuit 41 measurement electrode voltage acquisition circuit 42 reference electrode voltage acquisition circuit CL1 coupling capacitance CL2 coupling capacitance R0 resistance R1 resistance (resistor)
R2 resistor R11 resistor (calculation unit)
R12 resistance (calculation unit)

Claims (6)

  1. 　電線の交流電圧を電線の絶縁被覆を通して計測する電圧計測装置において、
    　前記絶縁被覆の周りに配置される計測電極および基準電極と、
    　前記交流電圧により前記計測電極に生じる計測電極電圧を取得する計測電極電圧取得回路と、
    　前記交流電圧により前記基準電極に生じる、前記交流電圧の位相に対して位相が一定量ずれている基準電極電圧を取得する基準電極電圧取得回路と、
    　前記計測電極電圧と前記基準電極電圧との位相差から、前記電線の心線と前記計測電極との間の結合容量を求め、求めた結合容量および前記計測電極電圧により前記交流電圧を求める演算部とを備えていることを特徴とする電圧計測装置。     In a voltage measuring device that measures the AC voltage of a wire through the insulation of the wire,
    A measurement electrode and a reference electrode disposed around the insulating coating;
    A measurement electrode voltage acquisition circuit for acquiring a measurement electrode voltage generated in the measurement electrode by the alternating voltage;
    A reference electrode voltage acquisition circuit that acquires a reference electrode voltage that is generated in the reference electrode by the AC voltage and that is out of phase by a certain amount with respect to the phase of the AC voltage;
    An arithmetic unit that obtains a coupling capacity between the core of the electric wire and the measurement electrode from a phase difference between the measurement electrode voltage and the reference electrode voltage, and obtains the AC voltage from the obtained coupling capacity and the measurement electrode voltage. And a voltage measuring device.
  2. 　前記基準電極電圧取得回路は、前記交流電圧の位相に対して位相が９０°ずれている前記基準電極電圧を取得することを特徴とする請求項１に記載の電圧計測装置。 The voltage measurement apparatus according to claim 1, wherein the reference electrode voltage acquisition circuit acquires the reference electrode voltage whose phase is shifted by 90 ° with respect to the phase of the AC voltage.
  3. 　前記計測電極電圧取得回路は、第１演算増幅器を備え、前記計測電極が抵抗器を介して前記第１演算増幅器の反転入力端子に接続されている反転増幅回路であり、
    　前記基準電極電圧取得回路は、第２演算増幅器を備え、前記基準電極が前記第２演算増幅器の反転入力端子に直接接続されている反転増幅回路であることを特徴とする請求項２に記載の電圧計測装置。     The measurement electrode voltage acquisition circuit is an inverting amplification circuit including a first operational amplifier, and the measurement electrode is connected to an inverting input terminal of the first operational amplifier via a resistor.
    3. The inverting amplifier circuit according to claim 2, wherein the reference electrode voltage acquisition circuit is an inverting amplifier circuit including a second operational amplifier, and the reference electrode is directly connected to an inverting input terminal of the second operational amplifier. Voltage measuring device.
  4. 　前記演算部は、前記計測電極電圧をゼロクロス点で二値化した信号である第１のパルス波を出力する第１のパルス波出力回路と、
    　前記基準電極電圧をゼロクロス点で二値化した信号である第２のパルス波を出力する第２のパルス波出力回路と、
    　前記第１のパルス波および前記第２のパルス波から前記計測電極電圧と前記基準電極電圧との位相差を示す位相差信号を出力する位相差信号出力回路と、
    　前記位相差信号から前記電線の心線と前記計測電極との間の結合容量を求め、求めた結合容量および前記計測電極電圧により交流電圧を求める計算部とを備えていることを特徴とする請求項１から３のいずれか１項に記載の電圧計測装置。     The calculation unit outputs a first pulse wave output circuit that outputs a first pulse wave that is a signal obtained by binarizing the measurement electrode voltage at a zero cross point;
    A second pulse wave output circuit that outputs a second pulse wave that is a signal obtained by binarizing the reference electrode voltage at a zero cross point;
    A phase difference signal output circuit that outputs a phase difference signal indicating a phase difference between the measurement electrode voltage and the reference electrode voltage from the first pulse wave and the second pulse wave;
    And a calculation unit that obtains a coupling capacity between the core of the electric wire and the measurement electrode from the phase difference signal, and obtains an AC voltage from the obtained coupling capacity and the measurement electrode voltage. Item 4. The voltage measuring device according to any one of Items 1 to 3.
  5. 　電線の交流電圧を電線の絶縁被覆を通して計測する電圧計測方法において、
    　前記電線の絶縁被覆の周りに計測電極を配置し、前記交流電圧により前記計測電極に生じる計測電極電圧を取得する計測電極電圧取得工程と、
    　前記電線の絶縁被覆の周りに基準電極を配置し、前記交流電圧により前記基準電極に生じる、前記交流電圧の位相に対して位相が一定量ずれている基準電極電圧を取得する基準電極電圧取得工程と、
    　前記計測電極電圧と前記基準電極電圧との位相差から、前記電線の心線と前記計測電極との間の結合容量を求め、求めた結合容量および前記計測電極電圧により前記交流電圧を求める演算工程とを備えていることを特徴とする電圧計測方法。     In the voltage measurement method that measures the AC voltage of the wire through the insulation of the wire,
    A measurement electrode is disposed around the insulation coating of the electric wire, and a measurement electrode voltage acquisition step of acquiring a measurement electrode voltage generated in the measurement electrode by the alternating voltage;
    A reference electrode voltage acquisition step of arranging a reference electrode around the insulation coating of the electric wire and acquiring a reference electrode voltage that is generated in the reference electrode by the AC voltage and whose phase is shifted by a certain amount with respect to the phase of the AC voltage. When,
    A calculation step of obtaining a coupling capacity between the core of the electric wire and the measurement electrode from a phase difference between the measurement electrode voltage and the reference electrode voltage, and obtaining the AC voltage from the obtained coupling capacity and the measurement electrode voltage. And a voltage measuring method.
  6. 　前記基準電極は、前記電線の絶縁被覆に対して接触せず、前記絶縁被覆との間に空間を有するように配置することを特徴とする請求項５に記載の電圧計測方法。 6. The voltage measuring method according to claim 5, wherein the reference electrode is arranged so as not to contact the insulating coating of the electric wire and to have a space between the insulating coating and the insulating coating.
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