JP7220500B2 - Isolated voltage measuring device - Google Patents

Description

The present invention relates to an insulated voltage measuring device that measures voltage applied to a voltage measurement target object.

As a device for measuring the voltage applied to a voltage measurement target object, there is a non-contact voltage detection device that measures the voltage applied to the conductor of an insulation-coated electric wire without contacting the conductor (for example, see Patent Document 1). This has a first electrode on the wire side and a second electrode for voltage detection in an insulating member, the second electrode is arranged on a part of the first electrode with a gap therebetween, and the outer surface of the insulating coating of the wire is It has a flexible detection probe that can be wound in close contact with the body.

In this detection probe, the capacitance Ca of the auxiliary capacitor formed between the first electrode and the second electrode is sufficiently smaller than the capacitance Cs between the conductor of the electric wire and the first electrode, and the detection probe A detection capacitor and a voltage detection circuit are connected to the auxiliary capacitor portion of , and the AC voltage V applied to the conductor of the electric wire is measured.

In other words, the input voltage Vin of the voltage detection circuit is Vin ≈ (Ca/Cin) V (Cin is the capacitance of the detection capacitor, V is the voltage to be measured), so the voltage to be measured (AC voltage of the wire conductor) Since V is represented by the ratio of the capacitance Ca of the auxiliary capacitor portion and the capacitance Cin of the detection capacitor, V is not affected by the capacitance Cs between the conductor of the electric wire and the first electrode. , the voltage measurement of the AC voltage of the electric wire conductor can be performed with high accuracy.

In addition, the applicant has filed Japanese Patent Application No. 2018-569076 (hereinafter referred to as the prior application) to suppress the influence of the floating capacitance of the electrode of the detection probe, and even if the type of the wire to be measured is different, the AC voltage of the conductor Developed and applied for a patent on an insulated voltage measuring device that can measure voltage with high accuracy. This insulated voltage measuring device has a conductor-side electrode that is arranged close to the outer surface of the voltage measurement target, and an output-side electrode that has a smaller area than the conductor-side electrode and is arranged to face the conductor-side electrode while maintaining a gap. and a detection probe provided between the conductor-side electrode and the output-side electrode and having a dielectric having a large insulation resistance and a small dielectric constant, and a voltage composed of an I / V conversion circuit (current-voltage conversion circuit) The current of the output side electrode is inputted by the detection section, and an output voltage Vout proportional to the current of the output side electrode is obtained.

JP 2012-163394 A

However, in Patent Document 1 and the previous application, the voltage of the conductor of the electric wire covered with insulation as the voltage measurement object is measured through the capacitance, so if there is another conductor nearby, The voltage component of another nearby conductor mixes in as a voltage noise component through the electrostatic capacitance generated between the conductor to be measured and the measurement electrode of the detection probe, resulting in an error, making highly accurate voltage measurement of the conductor impossible. Can not.

Also, if the conductor for voltage measurement is an insulated wire, the diameter of the conductor and the thickness of the insulation coating of the conductor will vary depending on the type of wire. The capacitance between the conductor and the measuring electrode changes. For this reason, it is necessary to take countermeasures when the types of electric wires to be measured are different.

FIG. 8 is an explanatory diagram of the insulated voltage measuring device of Patent Document 1. As shown in FIG. 8(a) is a schematic configuration diagram thereof, FIG. 8(b) is an equivalent circuit of FIG. 8(a), and FIG. 8(c) is a floating electrostatic capacitance Cs1 of the first electrode and a floating electrostatic This is an equivalent circuit considering the capacitance Ca1. As shown in FIG. 8, in measuring the AC voltage applied to the conductor 12 of the electric wire 11 to be measured for voltage (hereinafter referred to as the conductor 12 to be measured), a detection probe 13 is attached to the outer surface of the insulation coating of the electric wire 11 to be measured. Install. The detection probe 13 includes a large-area first electrode 14 on the side of the electric wire 11 to be measured and a part of the first electrode 14 in a flexible insulating member that can be wound in close contact with the outer surface of the insulating coating. It has a second electrode 15 with a small area for voltage detection that faces each other. A large-capacity detection capacitor Cin is connected after the second electrode 15, and the voltage of the detection capacitor Cin is measured by the voltage detection circuit 16, thereby measuring the AC voltage applied to the conductor 12 to be measured.

As shown in FIG. 8B, the capacitance Cs between the conductor of the electric wire and the first electrode 14 and the capacitance of the auxiliary capacitor formed between the first electrode 14 and the second electrode 15 A combined capacitance Cp with Ca is connected in series to the detection capacitor Cin. The detection capacitor Cin is a detection capacitor that is so large that the stray capacitance of the wire 11 to be measured can be ignored. Even if the stray capacitance Ca1 exists, it is designed not to be affected by the stray capacitances Cs1 and Ca1.

That is, the current from the second electrode 15, which has a low capacitance, is converted into the voltage Vin of the large-capacity detection capacitor Cin so that the stray capacitance of the cable can be ignored. For this reason, the current from the second electrode 15, which has a low capacitance, is very small, and the capacitance of the large-capacity capacitor Cin is large. susceptible to

Therefore, the applicant developed the isolated voltage measuring device of the previous application. FIG. 9 is an explanatory diagram of the insulated voltage measuring device of the previous application. In FIG. 9, a test voltage V1 is applied from an AC power supply 17 to the conductor 12 to be measured coated with an insulating coating 26, and the AC voltage V1 applied from the AC power supply 17 is the voltage of the conductor 12 to be measured. Become. In measuring the voltage of the conductor 12 to be measured, the detection probe 13 is attached to the outer surface of the insulating coating 26 of the wire 11 to be measured. The detection probe 13 is arranged to face the conductor-side electrode 18 which is arranged in contact with the outer surface of the insulating coating 26 of the electric wire 11 to be measured, and which has a smaller area than the conductor-side electrode 18 and is spaced apart from the conductor-side electrode 18 . and a dielectric 20 between the conductor-side electrode 18 and the output-side electrode 19 .

A capacitance C12 is generated between the conductor 12 to be measured and the output electrode 19 by the insulating coating 26 of the conductor 12 to be measured and the dielectric 20 . The voltage V1 of the conductor to be measured generates a current I1 due to the capacitance C12, and the current I1 is input to the voltage detector 21. FIG. The voltage detection unit 21 is formed by an I/V conversion circuit with small impedance. Also, a shield line 25 is arranged from the immediate vicinity of the output side electrode 19 to the negative input terminal of the operational amplifier 22 of the voltage detection section 21 to reduce the influence of the capacitance of the wiring from the output side electrode 19 to the voltage detection section 21. ing.

The current I1 from the output electrode 19 passes through the core wire of the shield wire 25 and is input to the negative terminal of the operational amplifier 22 of the voltage detection section 21, and the output voltage Vout of the voltage detection section 21 becomes Vout=-I1·Z. This is because the positive terminal of the operational amplifier 22 is grounded (GND), and the operational amplifier 22 operates so that the negative terminal has the same potential as the positive terminal. As a result, an output voltage Vout proportional to the current I1 from the output electrode 19 is obtained. Since the voltage V1 of the conductor 12 to be measured and the output voltage Vout of the measurement result have a proportional relationship with a specific proportional coefficient, the voltage V1 of the conductor 12 to be measured can be obtained from the output voltage Vout of the measurement result.

FIG. 10 shows the case in FIG. 9 when there is a conductor 29x of a first neighboring electric wire 28x coated with an insulating coating 26x (hereinafter referred to as first neighboring conductor 29x) in the vicinity of the conductor 12 to be measured coated with an insulating coating 26. It is explanatory drawing of the shown insulation type voltage measuring apparatus. In FIG. 10, the measured conductor 12 coated with the insulating coating 26 and the first neighboring conductor 29x coated with the insulating coating 26x are viewed from above.

A test voltage Vx is applied from the AC power supply 17x to the first neighboring conductor 29x coated with the insulating coating 26x, and the AC voltage Vx applied from the AC power supply 17x becomes the voltage of the first neighboring conductor 29x.

When the first neighboring conductor 29x is in the vicinity of the conductor 12 to be measured, a capacitance Cx1 is generated between the first neighboring conductor 29x and the output side electrode 19 of the detection probe 13 . Voltage Vx on first neighboring conductor 29x produces current Ix due to capacitance Cx1 between first neighboring conductor 29x and output electrode 19 . Therefore, a current (I1+Ix) in which the current I1 from the conductor 12 to be measured and the current Ix from the neighboring conductor 29 are mixed flows through the core wire of the shield wire 25. (I1+Ix) is input. Therefore, an error corresponding to the current Ix from the neighboring conductor 29 is generated in the output voltage Vout of the measurement result.

In other words, the isolated voltage measuring device of the prior application is effective when there is no other first neighboring conductor 29x in the vicinity of the conductor 12 to be measured, but the first neighboring conductor 29x , an error corresponding to the current Ix from the first neighboring conductor 29x occurs in the measured output voltage Vout.

Since an electric circuit transmits electrical energy by having forward and return conductors, there is usually a return conductor in the vicinity of the conductor to be measured. Also, when the conductor 12 to be measured is related to electric power, there are many three phases, and the number of wires in the electric circuit is often three. Moreover, various types of wiring, single-phase and three-phase, coexist in switchboards where measurements are often performed.

Thus, in Patent Document 1 and the prior application, if there is a conductor other than the conductor to be measured nearby, a A voltage component of another nearby conductor is mixed in through the capacitance, resulting in an error in the output voltage Vout of the measurement result, and highly accurate voltage measurement of the conductor cannot be performed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an insulated voltage measuring device capable of measuring the voltage of a conductor to be measured with high precision even when another conductor is placed in the vicinity of the conductor to be measured for voltage.

The insulated voltage measuring device according to the invention of claim 1 is arranged on the outer surface of a voltage measurement object and includes a voltage noise component due to a conductor of a nearby electric wire existing in the vicinity of the voltage measurement object. a detection probe that detects a voltage component to be measured of a conductor as a current; a voltage noise detection electrode that is arranged near the conductor of the neighboring electric wire and detects the voltage noise component containing the voltage component to be measured as a current; a current input calculation unit for inputting a current detected by a probe through a shielded wire and converting it into a voltage, and inputting a current detected by the voltage noise detection electrode through a shielded wire and converting it into a voltage; a correction voltage calculation unit for obtaining a measured voltage of the conductor of the voltage measurement object by removing the voltage noise component from the detected voltage in which the conductor measurement target voltage component and the voltage noise component are mixed and converted into a voltage by the calculation unit; characterized by comprising

The insulated voltage measuring apparatus according to the invention of claim 2 is arranged on the outer surface of a voltage measurement object and includes a voltage noise component due to a conductor of a nearby wire existing in the vicinity of the voltage measurement object. A detection probe for detecting a voltage component to be measured of a conductor as a current, and a shielded wire for extracting the current detected by the detection probe are further shielded to form a double shielded wire, which extends from the outer shield portion of the double shielded wire to the shielded wire. a voltage noise collective detection unit formed by exposing an end of a shield portion to the detection probe side and detecting, as a current, the voltage noise component containing the voltage component to be measured; The current detected by the voltage noise collective detection unit is input to the current-voltage conversion circuit from the core wire of the shielded wire and converted into a voltage. A current input calculation unit that converts the current detected by the voltage noise batch detection unit into a voltage, and a detection voltage that is a mixture of the conductor measurement target voltage component converted into a voltage by the current input calculation unit and the voltage noise component. and a correction voltage calculator that removes the voltage noise component and obtains the measured voltage of the conductor of the voltage measurement object.

According to the invention of claim 1, the detection probes arranged on the outer surface of the voltage measurement object measure the conductor of the voltage measurement object including the voltage noise component due to the conductors of the neighboring electric wires existing in the vicinity of the voltage measurement object. The target voltage component is detected by current, the voltage noise component including the target voltage component to be measured is detected by current by the voltage noise detection electrode installed near the conductor of the nearby electric wire, and the current and voltage noise detected by the detection probe are detected. The current detected by the electrodes is converted to voltage by the current input calculator, and the correction voltage calculator is used to extract the voltage noise from the detected voltage, which is a mixture of the conductor voltage component to be measured and the voltage noise component converted to voltage by the current input calculator. Since the measured voltage of the conductor of the object of voltage measurement is obtained by removing the component, the voltage of the conductor of object of measurement can be measured with high accuracy even when another conductor is arranged in the vicinity of the conductor of object of measurement.

According to the invention of claim 2, the shielded wire for taking out the current detected by the detection probe is a double shielded wire that is further shielded, and the end of the shielded part of the shielded wire is extended from the outer shield part of the double shielded wire to the detection probe. A voltage noise collective detection unit formed to be exposed to the side detects a voltage noise component including a voltage component to be measured as a current. Therefore, the current detected by the detection probe or the voltage noise batch detection section can be input to the current input calculation section regardless of the capacitance of the shield line or the double shield line or the change in capacitance due to routing.

The voltage noise batch detector has a circular structure with the end of the shielded wire exposed to the detection probe, so voltage noise due to the conductors of all neighboring wires that exist near the voltage measurement object is detected. components can be detected. The current input operation unit inputs the current detected by the voltage noise batch detection unit to the current-voltage conversion circuit through the shield portion of the shield wire, which can be regarded as being grounded. Then, the correction voltage calculation section removes the voltage noise component from the detected voltage, which is a mixture of the conductor measurement target voltage component and the voltage noise component converted into voltage by the current input calculation section, and obtains the measured voltage of the conductor of the voltage measurement target. Therefore, the voltage of the conductor to be measured can be measured with high accuracy even when another conductor is placed in the vicinity of the conductor to be measured for voltage.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows an example of the insulated voltage measuring device concerning 1st Embodiment of this invention. FIG. 2 is a circuit diagram of an equivalent circuit of the insulated voltage detection device shown in FIG. 1; FIG. 2 is a configuration diagram showing another example of the insulated voltage measuring device according to the first embodiment of the present invention; FIG. 4 is a configuration diagram showing another example of the insulated voltage measuring device according to the first embodiment of the present invention; The block diagram which shows an example of the insulation type voltage measuring device concerning 2nd Embodiment of this invention. FIG. 6 is a circuit diagram of an equivalent circuit of the insulated voltage detection device shown in FIG. 5; The block diagram which shows another example of the insulation type voltage measuring apparatus concerning 2nd Embodiment of this invention. FIG. 2 is an explanatory diagram of the insulated voltage measuring device of Patent Document 1; Explanatory drawing of the insulation type voltage measuring device of the prior application. FIG. 10 is an explanatory diagram of the insulated voltage measuring device shown in FIG. 9 when there is a conductor of an adjacent electric wire in the vicinity of the conductor of the electric wire to be measured;

Embodiments of the present invention will be described below. FIG. 1 is a configuration diagram showing an example of an insulated voltage measuring device according to a first embodiment of the present invention. FIG. 1 shows the case where two neighboring conductors 29, ie, a first neighboring conductor 29x and a second neighboring conductor 29y, exist in the vicinity of the conductor 12 to be measured. In the case of electric power, there are many three phases, so one of the three phases is the conductor 12 to be measured, and the first neighboring conductor 29x and the second neighboring conductor 29y are located on both sides of the conductor 12 to be measured. show.

A test voltage V 1 is applied from an AC power supply 17 to the conductor 12 to be measured covered with the insulating coating 26 , and the AC voltage V 1 applied from the AC power supply 17 becomes the voltage of the conductor 12 to be measured. On the other hand, the test voltage Vx is applied from the AC power supply 17x to the first neighboring conductor 29x coated with the insulating coating 26x, and the AC voltage Vx applied from the AC power supply 17x is the voltage of the first neighboring conductor 29x. Become. Similarly, a test voltage Vy is applied from the AC power supply 17y to the second neighboring conductor 29y coated with the insulating coating 26y, and the AC voltage Vy applied from the AC power supply 17y is the voltage of the second neighboring conductor 29y. becomes.

In measuring the voltage of the conductor 12 to be measured, the detection probe 13 is arranged on the outer surface of the insulating coating 26 of the electric wire 11 to be measured. The detection probe 13 has a dielectric 20A arranged in contact with the outer surface of the insulating coating 26 of the wire 11 to be measured and an output electrode 19 .

A capacitance Cm is generated between the conductor 12 to be measured and the output electrode 19 by the insulating coating 26 of the conductor 12 to be measured and the dielectric 20A. Due to this capacitance Cm, the voltage V1 on the conductor 12 to be measured produces a current I1. The current I1 is the current of the voltage component to be measured from the conductor 12 to be measured. Also, a capacitance Cx1 is generated between the first neighboring conductor 29x and the output side electrode 19 of the detection probe 13 . Voltage Vx on first neighboring conductor 29x produces current Ix due to capacitance Cx1 between first neighboring conductor 29x and output electrode 19 . Current Ix is the current of the voltage noise component from first neighboring conductor 29x. Similarly, a capacitance Cy1 is generated between the second neighboring conductor 29y and the output side electrode 19 of the detection probe 13. As shown in FIG. The voltage Vy on the second neighboring conductor 29y produces a current Iy due to the capacitance Cy1 between the first neighboring conductor 29x and the output electrode 19. FIG. Current Iy is the current of the voltage noise component from second neighboring conductor 29y.

Therefore, in the core wire of the shielded wire 25, current Im (=I1 +Ix+Iy) flows, and the current Im is input to the voltage detection section 21 of the current input calculation section 30 . That is, the current Im includes the current I1 of the voltage component to be measured of the conductor 12 to be measured, the current Ix of the voltage noise component due to the first neighboring conductor 29x existing near the conductor 12 to be measured, and the current Ix due to the second neighboring conductor 29y. A voltage noise component current Iy is included. This current Im is input to the negative terminal of the operational amplifier 22 of the voltage detection unit 21 of the current input calculation unit 30 through the core wire of the shield wire 25, and the output voltage Voutm of the voltage detection unit 21 becomes Voutm=-Im·Z. . As a result, the voltage detector 21 of the current input calculator 30 obtains the detected voltage Voutm proportional to the current Im. The detected voltage Voutm of the conductor 12 to be measured includes a voltage noise component corresponding to the current (Ix+Iy) from the nearby conductor 29 in addition to the voltage component to be measured corresponding to the current I1 from the conductor 12 to be measured. .

Next, voltage noise detection electrodes 27 are provided in the vicinity of the two first neighboring wires 28x and second neighboring wires 28y. FIG. 1 shows the case where two voltage noise detection electrodes 27x and 27y are provided, and shows the case where the two voltage noise detection electrodes 27x and 27y are attached to the dielectric 20A of the detection probe 13. Alternatively, another dielectric may be provided instead of the dielectric 20A, and the voltage noise detection electrodes 27x and 27y may be provided on the other dielectric. In that case, it is desirable that another dielectric to which the voltage noise detection electrodes 27x and 27y are attached is integrally attached to the detection probe 13. FIG. This is because when the detection probe 13 is placed on the wire 11 to be measured, the voltage noise detection electrode 27x is located at a position where the voltage of the first neighboring conductor 29x of the first neighboring wire 28x can be detected, and the voltage noise detection electrode 27y This is because it is located at a position where the voltage of the second neighboring conductor 29y of the second neighboring electric wire 28y can be detected.

Here, the output side electrode 19 of the conductor 12 to be measured is arranged as close as possible to the conductor 12 to be measured, and voltage noise detection electrodes 27x and 27y for detecting the voltages Vx and Vy of the first neighboring conductor 29x and the second neighboring conductor 29y. are positioned away from the conductor 12 to be measured.

The voltage noise detection electrode 27x is the total current Ix1 (=Ix2+Ix3) of the current Ix2 flowing in the capacitance Cx2 between the first neighboring conductor 29x and the current Ix3 flowing in the capacitance Cx3 between the conductor 12 to be measured. is detected and input to the voltage detection section 21x of the current input calculation section 30 as the detection current Ix1 (=Ix2+Ix3) of the voltage noise detection electrode 27x. Current Ix2 is the voltage noise component from first neighboring conductor 29x, and current Ix3 is the current of the voltage component to be measured from conductor 12 to be measured. That is, the current Ix1 includes the current Ix3 of the voltage component to be measured from the conductor 12 to be measured in addition to the current Ix2 of the voltage noise component from the first neighboring conductor 29x. This current Ix1 passes through the core wire of the shield wire 25 and is input to the negative terminal of the operational amplifier 22x of the voltage detection section 21x of the current input calculation section 30, and the output voltage Voutx of the voltage detection section 21x becomes Voutx=-Ix1Z. . As a result, the voltage detector 21x of the current input calculator 30 obtains the detected voltage Voutx proportional to the current Ix1 (=Ix2+Ix3).

The detected voltage Voutx of the voltage noise detection electrode 27x is applied to the current Ix2 (voltage noise component current) flowing through the capacitance Cx2 between the first neighboring conductor 29x and the capacitance Cx3 between the conductor 12 to be measured. It is a mixed voltage of the voltage component to be measured and the voltage noise component due to the flowing current Ix3 (the current of the voltage component to be measured).

Similarly, the voltage noise detection electrode 27y is the total current Iy1 ( =Iy2+Iy3) is detected and input to the voltage detection unit 21y of the current input calculation unit 30 as the detected current Iy1 (=Iy2+Iy3) of the voltage noise detection electrode 27y. Current Iy2 is the voltage noise component from second neighboring conductor 29y, and current Iy3 is the current of the voltage component to be measured from conductor 12 to be measured. That is, the current Iy1 includes the current Iy3 of the voltage component to be measured from the conductor 12 to be measured in addition to the current Iy2 of the voltage noise component from the second neighboring conductor 29y. The current Ix1 and the current Iy1 are input to the negative terminal of the operational amplifier 22y of the voltage detection unit 21y of the current input calculation unit 30 through the core wire of the shield wire 25, and the output voltage Vouty of the voltage detection unit 21y is Vouty=-Iy1Z becomes. As a result, the voltage detector 21y of the current input calculator 30 obtains the detected voltage Vouty proportional to the current Iy1 (=Iy2+Iy3).

The detected voltage Vouty of the voltage noise detection electrode 27y is applied to the current Iy2 (voltage noise component current) flowing through the capacitance Cy2 between the second neighboring conductor 29y and the capacitance Cy3 between the conductor 12 to be measured. It is a mixed voltage of the voltage component to be measured and the voltage noise component due to the flowing current Iy3 (current of the voltage component to be measured).

The detected voltage Voutm of the voltage detector 21 of the current input calculator 30, the detected voltage Voutx of the voltage detector 21x of the current input calculator 30, and the detected voltage Vouty of the voltage detector 21y of the current input calculator 30 are corrected voltage calculations. It is input to the part 31 . In the correction voltage calculator 31, the voltage noise component corresponding to the current (Ix+Iy) from the neighboring conductor 29 from the detected voltage Voutm of the conductor 12 to be measured, and the current Ix2 from the neighboring conductor 29x from the detected voltage Voutx of the voltage noise detection electrode 27x. and the voltage noise component corresponding to the current Iy2 from the neighboring conductor 29y are removed from the detected voltage Vouty of the voltage noise detection electrode 27y, and the measured voltage of the conductor 12 to be measured is output as the output voltage Vout. That is, the correction voltage calculation unit 31 obtains the measured voltage value of the voltage to be measured V1, for example, by the calculation formula shown in (1) below, and outputs it as the output voltage Vout.

Vout= K1×(Voutm−(K2×Voutx+K3×Vouty)) … (1)
In equation (1), K1 is a coefficient for determining the correspondence between the output voltage Vout and the voltage of the conductor 12 to be measured (voltage to be measured) V1 so as to be 1 V at 100 Vrms. K2 is a coefficient that makes the voltage noise component included in Voutx the same level as the voltage noise component included in Voutm, and K3 makes the voltage noise component included in Vouty the same level as the voltage noise component included in Voutm. is a coefficient such as As a result, voltage noise components due to neighboring voltages Vx and Vy can be removed, and the value of the voltage V1 to be measured can be accurately obtained.

As described above, the output side electrode 19 of the conductor 12 to be measured is arranged as close as possible to the conductor 12 to be measured, and the voltage noise detection electrode 27x for detecting the voltages Vx and Vy of the first neighboring conductor 29x and the second neighboring conductor 29y. , 27y are located away from the conductor 12 to be measured, so the following equations (2a), (2b), and (2c) hold.

Cm>Cx1, Cy1 (2a)
Cm>Cx2, Cy2 (2b)
Cm>Cy3, Cx3 (2c)
however,
Cm: the capacitance between the conductor 12 to be measured and the output electrode 19 Cx1: the capacitance between the first neighboring conductor 29x and the output electrode 19 Cy1: the second neighboring conductor 29y and the output electrode 19 Capacitance Cx2 between: Capacitance Cy2 between the first neighboring conductor 29x and the voltage noise detection electrode 27x: Capacitance Cx3 between the second neighboring conductor 29y and the voltage noise detection electrode 27y: Object to be measured Capacitance Cy3 between conductor 12 and voltage noise detection electrode 27x: Capacitance between conductor 12 to be measured and voltage noise detection electrode 27y.

FIG. 2 is a circuit diagram of an equivalent circuit of the insulated voltage detection device shown in FIG. The output electrode 19 of the conductor 12 to be measured has a capacitance Cx1 to the first neighboring conductor 29x and an electrostatic capacitance Cx1 to the second neighboring conductor 29y in addition to the capacitance Cm to the conductor 12 to be measured. A capacitance Cy1 is generated. Therefore, the currents Ix and Iy due to the components of the neighboring voltages Vx and Vy are mixed into the current I1 due to the components of the voltage V1 of the conductor 12 to be measured. Further, a current Ix1 is generated by the voltage V1 component of the conductor 12 to be measured and the nearby voltage Vx component, and similarly, a current Iy1 is generated by the voltage V1 component of the measured conductor 12 and the nearby voltage Vy component.

The current I1 in FIG. 2 is the current (current from the output side electrode 19) flowing through the capacitance Cm due to the voltage V1 of the conductor to be measured, and is the current of the voltage component to be measured. The current Ix is the current that flows through the capacitance Cx1 due to the voltage Vx of the first neighboring conductor 29x, and is the current of the voltage noise component. The current Iy is the current that flows through the capacitance Cy1 due to the voltage Vy of the second neighboring conductor 29y, and is the current of the voltage noise component. The current Ix1 is the current that flows through the capacitance Cx2 due to the voltage Vx of the first neighboring conductor 29x (current of the voltage noise component) and the current that flows through the capacitance Cx3 due to the voltage V1 of the conductor to be measured (current of the voltage component to be measured). is the total current of The current Iy1 is a current (voltage noise component current) flowing through the capacitance Cy2 due to the voltage Vy of the second neighboring conductor 29y and a current flowing through the capacitance Cy3 (measurement voltage component current) due to the voltage V1 of the conductor to be measured. is the total current of

As shown in the above formulas (2a) to (2c), the capacitance Cm between the output side electrode 19 of the conductor 12 to be measured is equal to the other capacitances Cx1, Cy1, Cx2, Cy2, Cy3, Cx3 Therefore, the current I1 from the output side electrode 19 contains more components of the voltage V1 to be measured than the currents Ix1 and Iy1.

Further, from the positional relationship between the detection target conductor 12, the first neighboring conductor 29x, the second neighboring conductor 29y, the detection probe 13 (the output side electrode 19), and the voltage noise detection electrodes 27x, 27y, the following (3a), ( 3b) Formula holds.

Cx2> Cx1 (3a)
Cy2>Cy1 (3b)
Therefore, the current Ix1 from the voltage noise detection electrode 27x contains many components of the neighboring voltage Vx. The current Iy1 from the voltage noise detection electrode 27y contains many components of the neighboring voltage Vy.

Also, a capacitance Cx3 is generated between the voltage noise detection electrode 27x and the conductor 12 to be measured. , the current Ix1 flowing from the voltage noise detection electrode 27x has a smaller component of the voltage V1 to be measured than the current I1 from the output electrode 19x. Similarly, a capacitance Cy3 is generated between the voltage noise detection electrode 27y and the conductor 12 to be measured. In the current Iy1 flowing from the electrode 27y, the component of the voltage V1 to be measured is smaller than the current I1 from the output side electrode 19. FIG.

Then, as described above, in the current input calculation unit 30, the detection voltage Voutm proportional to the current I1 from the output side electrode 19, the detection voltage Voutx proportional to the current Ix1 flowing from the voltage noise detection electrode 27x, and the voltage noise detection electrode A detection voltage Vouty proportional to the current Iy1 flowing from 27y is obtained and output to the correction voltage calculation unit 31. FIG.

In the correction voltage calculator 31, the voltage noise component corresponding to the current (Ix+Iy) from the neighboring conductor 29 from the detected voltage Voutm of the conductor 12 to be measured, and the current Ix2 from the neighboring conductor 29x from the detected voltage Voutx of the voltage noise detection electrode 27x. and the voltage noise component corresponding to the current Iy2 from the neighboring conductor 29y are removed from the detected voltage Vouty of the voltage noise detection electrode 27y, and the measured voltage of the conductor 12 to be measured is output as the output voltage Vout.

According to the first embodiment, the voltage noise detection electrodes 27x and 27y are provided for the neighboring electric wires 28x and 28y existing in the vicinity of the voltage measurement object 11, and the voltage of the neighboring conductors 29x and 29y is the detection voltage of the measurement object conductor 12. Detect voltage noise components that affect Then, the current input calculator 30 obtains the detected voltage Voutm of the conductor 12 to be measured detected by the detection probe 13 and the detected voltages Voutx and Vouty detected by the voltage noise detection electrodes 27x and 27y. Since the measured voltage of the conductor 12 to be measured is obtained as the output voltage Vout by removing the voltage noise components due to the neighboring voltages Vx and Vy from Voutx and Vouty, the measurement can be performed even when the neighboring conductors 29x and 29y are arranged in the vicinity of the conductor 12 to be measured. The voltage of the target conductor 12 can be measured with high accuracy.

Depending on the position of the electrodes and the area of the voltage noise detection electrode 27 and the output side electrode 19, the equations (3a) and (3b) may not hold. If so, the current Im contains many components of the voltage V1 to be measured. Therefore, either change the I/V conversion coefficients K2 and K3 that convert the voltage noise detection currents Iy1 and Ix1 into Vouty and Voutx, or change the correction voltage By adjusting K2 and K3 in the arithmetic expression (1) in the arithmetic unit, it is possible to obtain the detection voltage Vout, which is the component output of the voltage V1 to be measured.

In the above description, the case of two adjacent conductors 29x and 29y has been described, but the case where m voltage noise detection electrodes 27 are provided for n adjacent conductors 29 is similarly applicable. Each of the m voltage noise detection electrodes 27 will detect voltage noise due to the measured voltage component of the conductor under test 12 and all n neighboring conductors 29, but not voltage noise due to the nearest neighboring conductors 29. Mainly to detect.

Further, in the above description, the detection probe 13 has the dielectric 20A and the output side electrode 19 arranged in contact with the outer surface of the insulating coating 26 of the electric wire 11 to be measured. Thus, the conductor-side electrode 18 may be provided on the side of the electric wire 11 to be measured of the dielectric 20A. Thereby, the conductor-side electrode 18 is arranged in contact with the outer surface of the insulating coating 26 of the electric wire 11 to be measured. The conductor-side electrode 18 is larger than the output-side electrode 19 and is formed so that the dielectric 20A is positioned between the conductor-side electrode 18 and the output-side electrode 19 . By providing the conductor-side electrode 18, it is possible to reduce the influence of the wire diameter (diameter of the thickness of the insulating coating) of the wire 11 to be measured and the diameter of the conductor. Since other configurations are the same as those of the insulated voltage measuring apparatus shown in FIG. 1, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

In the above description, as shown in FIGS. 1 and 3, the dielectric 20A of the detection probe 13 is brought into contact with the outer surface of the insulating coating 26 of the wire 11 to be measured, and the detection probe 13 is arranged on the wire 11 to be measured. However, in contrast to the example shown in FIG. 1, as shown in FIG. 4, a distance is maintained so that the detection probe 13 and the dielectric 20A do not come into contact with the outer surface of the insulating coating 26 of the electric wire 11 to be measured. It is also possible to place FIG. 4 shows the case where the output side electrode 19 is embedded in the dielectric 20A. In the other example shown in FIG. 3, similarly, it is possible to arrange the detection probe 13 and the dielectric 20A at intervals so that they do not come into contact with the outer surface of the insulating coating 26 of the electric wire 11 to be measured. be.

Next, a second embodiment of the invention will be described. FIG. 5 is a configuration diagram showing an example of an insulated voltage measuring device according to a second embodiment of the present invention. This second embodiment differs from the first embodiment shown in FIG. 1 in that the shielded wire 25 for taking out the current from the output side electrode 19 of the detection probe 13 is further shielded by a double shielded wire 32 . The end portion of the shield portion of the shield wire 25 (the inner shield portion of the double shield wire 32) exposed from the outer shield portion of 32 to the detection probe 13 side serves as a voltage noise collective detection portion 33. FIG. The voltage noise collective detection unit 33 can collectively detect the voltage noise components of each of the plurality of adjacent conductors 29, and even if the positional relationship between the measurement object wire 11 and the adjacent wire 28 is not constant, the adjacent wire 28 can be detected in a general manner. It is designed to be able to reduce the influence of The same elements as those in FIG. 1 are denoted by the same reference numerals, and overlapping descriptions are omitted.

In FIG. 5, the double shielded wire 32 has a double shield structure, and the end of the shielded portion of the shielded wire 25 exposed from the outer shield portion of the double shielded wire 32 serves as the voltage noise collective detection portion 33. . Since the voltage noise collective detection portion 33 is the end portion of the shield portion of the shield wire 25 exposed from the outer shield of the double shield wire 32, it has a circular structure and a circular cross section. Therefore, since the electric field from the neighboring conductor 29 can be captured regardless of the positional relationship of the neighboring conductors 29x and 29y, the voltage noise component of the voltage of the neighboring conductor 19 affecting the detected voltage of the conductor 12 to be measured can be detected. .

In addition, since the voltage noise collective detection section 33 is positioned perpendicular to the output side electrode 19 that detects the voltage V1 of the measurement target conductor 12, the voltage noise collective detection section 33 detects the The capacitance Cxy with respect to it becomes smaller. In addition, since the voltage noise collective detection section 33 is close to the output side electrode 19 in terms of distance, it can detect an equivalent component to the electric field component applied to the output side electrode 19 by the neighboring conductor 29 . That is, the voltage noise component in which the voltage of the neighboring conductor 19 affects the detected voltage of the conductor 12 to be measured can be detected with high accuracy.

A capacitance Cm is generated between the conductor 12 to be measured and the output electrode 19 by the insulating coating 26 of the conductor 12 to be measured and the dielectric 20 . Due to this capacitance Cm, the voltage V1 on the conductor 12 to be measured produces a current I1. The current I1 is the current of the voltage component to be measured from the conductor 12 to be measured. Also, a capacitance Cx1 is generated between the first neighboring conductor 29x and the output side electrode 19 of the detection probe 13 . A voltage Vx on the first neighboring conductor 29x produces a current Ix due to this capacitance Cx1. Current Ix is the current of the voltage noise component from first neighboring conductor 29x. Similarly, a capacitance Cy1 is generated between the second neighboring conductor 29y and the output side electrode 19 of the detection probe 13. As shown in FIG. The voltage Vy on the second neighboring conductor 29y produces a current Iy due to this capacitance Cy1. Current Iy is the current of the voltage noise component from second neighboring conductor 29y.

Therefore, in the core wire of the shielded wire 25, current Im (=I1 +Ix+Iy) flows, and the current Im is input to the voltage detection section 21m of the current input calculation section 30 . That is, the current Im includes the current I1 of the voltage component to be measured of the conductor 12 to be measured, the current Ix of the voltage noise component due to the first neighboring conductor 29x existing near the conductor 12 to be measured, and the current Ix due to the second neighboring conductor 29y. A voltage noise component current Iy is included. This current Im is input to the negative terminal of the operational amplifier 22 of the voltage detection unit 21m of the current input calculation unit 30 through the core wire of the shield wire 25, and the output voltage Vo1 of the voltage detection unit 21m becomes Vo1=-Im·Z. . As a result, the voltage detector 21m of the current input calculator 30 obtains the detected voltage Vo1 proportional to the current Im (=I1+Ix+Iy). The detected voltage Vo1 of the conductor 12 to be measured includes a voltage noise component corresponding to the current (Ix+Iy) from the nearby conductor 29 in addition to the voltage component to be measured corresponding to the current I1 from the conductor 12 to be measured.

Next, since the voltage V1 of the conductor 12 to be measured is applied to the voltage noise batch detector 33, a current Ixy is generated through the capacitance Cxy between the voltage noise batch detector 33 and the conductor 12 to be measured. The current Ixy is the current of the voltage component to be measured from the conductor 12 to be measured. In addition, since the voltage Vx of the first neighboring conductor 29x is applied to the voltage noise collective detection unit 33, the current Ix1 is generated through the capacitance Cx2 between the voltage noise collective detection unit 33 and the first neighboring conductor 29x. occur. Current Ix1 is the current of the voltage noise component from first neighboring conductor 29x. Similarly, since voltage Vy of the second neighboring conductor 29y is applied to the voltage noise collective detection unit 33, the current Iy1 is generated through the capacitance Cy2 between the voltage noise collective detection unit 33 and the second neighboring conductor 29y. occurs. Current Iy1 is the current of the voltage noise component from second neighboring conductor 29y.

Therefore, a current Ik (=Ixy+Ix1+Iy1) flows through the shield portion of the shield wire 25 and is input to the voltage detection portion 21k of the current input calculation portion 30 . That is, the current Ik includes the current Ix1 of the voltage noise component from the first neighboring conductor 29x and the current Iy1 of the voltage noise component from the second neighboring conductor 29y, and the current Ixy of the voltage component to be measured from the conductor 12 to be measured. ing. This current Ik passes through the shield portion of the shield wire 25 and is input to the negative terminal of the operational amplifier 22k of the voltage detection portion 21k of the current input calculation portion 30, and the output voltage Vo2 of the voltage detection portion 21 is Vo2=-Ik·Z. Become. As a result, the voltage detector 21k of the current input calculator 30 obtains the detected voltage Vo2 proportional to the current Ik (=Ixy+Ix1+Iy1). In the detected voltage Vo2 of the conductor 12 to be measured, a voltage noise component corresponding to the current (Ixy) from the conductor 12 to be measured and a voltage noise component corresponding to the current (Ix1+Iy1) from the adjacent conductor 29 are mixed.

The detected voltage Vo<b>1 of the voltage detector 21 of the current input calculator 30 and the detected voltage Vo<b>2 of the voltage detector 21 k of the current input calculator 30 are input to the correction voltage calculator 31 . In the correction voltage calculation unit 31, the voltage noise component corresponding to the current (Ix+Iy) from the neighboring conductor 29 from the detected voltage Vo1 of the conductor 12 to be measured, the neighboring conductor 29 (first neighboring conductor 29x, second neighboring conductor 29y) The voltage noise component corresponding to the current (Ix1+Iy1) from the adjacent conductor 29 is removed from the detected voltage Vo2, and the measured voltage of the conductor 12 to be measured is output as the output voltage Vout. That is, the correction voltage calculation unit 31 obtains the measured voltage value of the voltage V1 to be measured by the following calculation formula (4), for example, and outputs it as the output voltage Vout.

Vout=K11×(Vo1−(K12×Vo2)) … (4)
In the equation (4), K11 is a coefficient for setting the correspondence between the output voltage Vout and the voltage (voltage to be measured) V1 of the conductor 12 to be measured so as to be 1 V at 100 Vrms. K12 is a coefficient such that the voltage noise component contained in V02 is at the same level as the voltage noise component contained in V01. As a result, voltage noise components due to neighboring voltages Vx and Vy can be removed, and the value of the voltage V1 to be measured can be accurately obtained.

FIG. 6 is an equivalent circuit of the insulated voltage detector shown in FIG. Since the voltage V1 of the conductor 12 to be measured is applied to the output side electrode 19 of the detection probe 13 through the capacitance Cm, a current I1 is generated. Current I1 is the current of the voltage component to be measured. Also, since the voltages Vx and Vy of the first neighboring conductor 29x and the second neighboring conductor 29y are applied to the output side electrode 19 of the detection probe 13 through the capacitances Cx1 and Cy1, currents Ix and Iy are generated. Current Ix is the current of the voltage noise component due to the first neighboring conductor 29x, and current Iy is the current of the voltage noise component due to the second neighboring conductor 29y. Therefore, a current Im (=I1+Ix+Iy) flows through the core wire of the shield wire 25 . The current Im includes the current I1 (current of the voltage component to be measured) due to the voltage V1 of the conductor to be measured, and the currents Ix and Iy (current of voltage noise components) due to the voltages Vx and Vy of the first neighboring conductor 29x and the second neighboring conductor 29y. ) are mixed.

On the other hand, since the voltage V1 of the conductor 12 to be measured is applied to the voltage noise collective detection unit 33 through the capacitance Cxy, a current Ixy is generated. The current Ixy is the current of the voltage component to be measured from the conductor 12 to be measured. In addition, since the voltages Vx and Vy of the first neighboring conductor 29x and the second neighboring conductor 29y are applied to the voltage noise collective detection unit 33 through the capacitances Cx2 and Cy2, currents Ix1 and Iy1 are generated. Current Ix1 is the voltage noise component from the first neighboring conductor 29x, and current Iy1 is the voltage noise component current from the second neighboring conductor 29y. Therefore, a current Ik (=Ixy+Ix1+Iy1) flows through the shield portion of the shield wire 25 . The current Ik includes the current Ixy (current of the voltage component to be measured) due to the voltage V1 of the conductor to be measured and the currents Ix1 and Iy1 due to the voltages Vx and Vy of the first neighboring conductor 29x and the second neighboring conductor 29y (voltage noise component currents) are mixed.

Therefore, in the equation (4), the current Ik flowing through the shield portion of the shield wire 25 is set to the coefficient K12 so that the voltage noise components of the neighboring voltages Vx and Vy contained in the current Im flowing through the core wire of the shield wire 25 have the same level. Multiply. As described above, the coefficient K11 is a coefficient for making the correspondence between the output voltage Vout and the voltage (voltage to be measured) V1 of the conductor 12 to be measured 1 V at 100 Vrms. As a result, the output voltage Vout corresponds only to the voltage V1 to be measured.

Here, in FIG. 5, the shield part of the shield wire 25 constituting the voltage noise collective detection part 33 is not connected to the ground (GND), but the negative voltage of the operational amplifier 22k of the voltage detection part 21k of the current input calculation part 30 is Connected to the input terminal, the voltage detector 21k constitutes an I/V conversion circuit. Since the negative input terminal of the I/V conversion circuit has the same potential as the GND potential of the operational amplifier 22k, the electrical relationship of the shielded wire 25 viewed from the output side electrode 19 is the shielded wire 25 shown in FIG. It becomes the same as the shielded wire 25).

Therefore, the current Im from the output side electrode 19 is sent to the voltage detection section 21m of the current input calculation section 30 as the current Im regardless of the capacitance of the shield wire 25 or the double shield wire 32 and the capacitance change due to routing. is entered. Furthermore, as described above, since the voltage noise collective detection section 33 has a circular structure, it does not require a plurality of voltage noise detection electrodes 27 unlike the first embodiment shown in FIG. In addition, since the parts other than the voltage noise collective detection part 33 of the shield line 25 are covered with GND by the outer shield part of the double shield line 32, they are not affected by the external electric field of the part where the double shield line 32 is routed.

Further, in the above description, the detection probe 13 has the dielectric 20A and the output side electrode 19 arranged in contact with the outer surface of the insulating coating 26 of the electric wire 11 to be measured. Thus, the conductor-side electrode 18 may be provided on the side of the electric wire 11 to be measured of the dielectric 20A. Thereby, the conductor-side electrode 18 is arranged in contact with the outer surface of the insulating coating 26 of the electric wire 11 to be measured. The conductor-side electrode 18 is larger than the output-side electrode 19 and is formed so that the dielectric 20A is positioned between the conductor-side electrode 18 and the output-side electrode 19 . By providing the conductor-side electrode 18, it is possible to reduce the influence of the wire diameter (diameter of the thickness of the insulating coating) of the wire 11 to be measured and the diameter of the conductor. Other configurations are the same as those of the insulated voltage measuring device shown in FIG. The shielded wire 25 for extracting the current from the output side electrode 19 of 13 is further shielded by a double shielded wire 32, and the end of the shielded portion of the shielded wire 25 exposed from the outer shield of the double shielded wire 32 to the detection probe 13 side. is used as the voltage noise batch detector 33, the output side electrode 19 of the detection probe 13 remains the same as the structure of the output side electrode 19 in FIG. It is possible to realize an insulated voltage measuring device that can be used even in a field with small-diameter electric wires. In addition, even when the positional relationship between the wire 11 to be measured and the adjacent wire 29 is not constant, it is possible to realize an insulated voltage measuring device that can be used.

Although several embodiments of the invention have been described above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 11... Wire to be measured, 12... Conductor to be measured, 13... Detection probe, 14... First electrode, 15... Second electrode, 16... Voltage detection circuit, 17... AC power supply, 18... Conductor side electrode, 19... Output side Electrodes 20, 20A Dielectric 21 Voltage detection part 22 Operational amplifier 23 Detection probe holding part 24 Recess 25 Shield wire 26 Insulation coating 27 Voltage noise detection electrode 28 Neighborhood Electric wire 29 Proximity conductor 30 Current input calculation unit 31 Correction voltage calculation unit 32 Double shielded wire 33 Voltage noise batch detection unit

Claims (2)

a detection probe that is arranged on the outer surface of a voltage measurement object and detects, by means of a current, a voltage component to be measured of a conductor of the voltage measurement object that includes a voltage noise component due to a conductor of a nearby electric wire that exists in the vicinity of the voltage measurement object; ,
a voltage noise detection electrode that is arranged near the conductor of the neighboring electric wire and detects the voltage noise component containing the voltage component to be measured as a current;
a current input calculation unit that inputs the current detected by the detection probe through a shielded wire and converts it into a voltage, and inputs the current detected by the voltage noise detection electrode through a shielded wire and converts it into a voltage;
A correction voltage for obtaining a measured voltage of the conductor of the voltage measurement object by removing the voltage noise component from the detected voltage in which the conductor measurement object voltage component and the voltage noise component are mixed and converted into a voltage by the current input calculation unit. An insulated voltage measuring device, comprising: a computing unit. a detection probe that is arranged on the outer surface of a voltage measurement object and detects, by means of a current, a voltage component to be measured of a conductor of the voltage measurement object that includes a voltage noise component due to a conductor of a nearby electric wire that exists in the vicinity of the voltage measurement object; ,
The shielded wire for taking out the current detected by the detection probe is formed as a double shielded wire that is further shielded so that the end of the shield part of the shielded wire is exposed from the outer shield part of the double shielded wire to the detection probe side. a voltage noise batch detection unit that detects the voltage noise component including the voltage component to be measured as a current;
a shield portion of the shield line that inputs the current detected by the detection probe from the core wire of the shield line to a current-voltage conversion circuit and converts it into a voltage, and that can regard the current detected by the voltage noise collective detection portion as being grounded; a current input calculation unit for converting the current detected by the voltage noise collective detection unit into a voltage by inputting the current to the current-voltage conversion circuit via the
A correction voltage for obtaining a measured voltage of the conductor of the voltage measurement object by removing the voltage noise component from the detected voltage in which the conductor measurement object voltage component and the voltage noise component are mixed and converted into a voltage by the current input calculation unit. An insulated voltage measuring device, comprising: a computing unit.

Images