JPH10206466A - Voltage-measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a voltage detecting electrode difficult to have temperature effect due to dust or the like attached to a sensor by covering the voltage detecting electrode with an insulating film. SOLUTION: A hook-like electrode 1 is formed of a U-shaped electrode 2 with approximately U-shaped cross section and the U-shaped electrode 2 is covered with an insulating coating 3. The insulating coating 3 is formed of the insulating coating of an insulator, preferably resin, almite or the like having a drainage property for example. Also, the insulating coating 3 is formed while the U-shaped electrode 2 is provided with a hole, so that the adhesion of both electrode and coating can be increased. An electric wire for measuring voltage is mounted on the inside of the insulating coating 3 as an electric wire wiring part 4. Since the electric wire is disposed thus on the electric wire wiring part 6, and voltage shared by the U-shaped electrode 2 is supplied to a sensor part, the voltage applied to the electric wire can be measured. Then, the U-shaped electrode 2 is covered with the insulating coating 3, so that the insulating resistance due to the insulating coating 3 is equivalently connected in series to the insulating resistance of the sensor part. Thus, the sensor part can be made difficult to be affected by temperature effect due to dust or the like attached to the sensor part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage measuring device capable of measuring a voltage of an electric wire in a non-contact manner.

[0002]

2. Description of the Related Art A voltage measuring device for measuring the voltage of a covered electric wire in a non-contact manner using a high impedance voltage measuring means has
Generally known. FIG. 3 is a schematic diagram showing the principle of such a voltage measuring device. The illustrated voltage measuring device is a coated electric wire 40 in which a core wire 40a is covered with an insulating coating 40b.
(Shown in cross-section). That is, the voltage measuring device includes a hook-shaped electrode 41 serving as a voltage detecting electrode on which the insulated wire 40 is placed, a sensor unit 42 constituted by, for example, a high-impedance voltage detecting means such as a Pockels effect element, The sensor unit 42 includes a measuring unit 43 that measures a phase difference between the intrinsic polarizations.

The Pockels effect is a phenomenon (electro-optic effect) in which the birefringence induced in the Pockels element, that is, the phase difference between the intrinsic polarizations is proportional to the strength of the electric field applied to the Pockels element. The principle of this voltage measuring device is
For example, the capacitance C between the covered wire 40 and the hook-shaped electrode 41
1 and the capacitance Cs of the sensor section 42 divide the voltage V1 of the covered electric wire 40. At this time, the voltage Vs shared by the sensor unit 42 is

(Equation 1) Becomes Here, for example, if C1≫Cs,

(Equation 2) And Vs ≒ V1. By the way, since the capacitance Cs of the sensor unit 42 is smaller than the capacitance C1, a voltage Vs substantially equal to the voltage V1 is applied to the sensor unit 42.
Is applied to Then, in the sensor section 42, the voltage V
A phase difference between the intrinsic polarizations according to the magnitude of 1 is generated. Thereby, the voltage V1 applied to the coated electric wire 40 can be measured by measuring the phase difference between the intrinsic polarized lights in the measuring unit 43. In this case, if C1≫Cs, even if the value of the capacitance C1 slightly changes, there is almost no effect on the measured voltage value.

[0004]

FIG. 4 is a diagram showing an equivalent circuit of the voltage measuring device shown in FIG. Resistance R
1 corresponds to the insulation resistance of the insulation coating 40b of the insulated wire 40 and is an extremely large value, so that it does not cause a measurement error. Further, the capacitance C2 in the sensor unit 42
Can be reduced depending on installation conditions and the like. However, the insulation resistance Rs of the hook-shaped electrode 41
When the humidity is increased due to dust or the like due to dew condensation or the like when used for a long period of time, the resistance value of the insulation resistance Rs becomes small depending on the measurement condition, which causes a measurement error. Therefore, it is difficult to perform stable voltage measurement.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and includes a voltage detecting electrode arranged close to an electric wire and a voltage shared by the voltage detecting electrode. In a voltage measuring device including a sensor unit for detecting, the voltage detecting electrode is covered with insulating means to constitute a voltage measuring device.

According to the present invention, since the voltage detecting electrode is covered with the insulating film, when measuring the voltage, the insulating resistance of the insulating means covering the voltage detecting electrode is equivalently connected in series with the insulating resistance of the sensor. Is connected to the sensor, it is possible to make the sensor less susceptible to humidity due to dust adhering to the sensor and dew condensation and the like. Thus, stable voltage measurement can be performed regardless of the environment in which the voltage measurement is performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the voltage measuring device according to the present invention will be described below. FIG. 1 is a perspective view showing an example of a hook-shaped electrode for voltage measurement provided in the power supply measuring device according to the present embodiment, FIG. 2A is a front view of the hook-shaped electrode shown in FIG. 1, and FIG. FIG. 2 is a sectional view taken along the line AA shown in FIG. 1.

As shown in FIG. 2B, the hook-shaped electrode 1 is formed by a U-shaped electrode 2 having a substantially U-shaped cross section.
Is covered with an insulating coating 3. The U-shaped electrode 2 corresponds to the hook-shaped electrode 41 described above with reference to FIG. The insulating coating 3 is formed of, for example, a resin having an insulating property, preferably a water-repellent property, or an insulating coating made of alumite or the like. Alternatively, insulating coating 3 made of ceramic or the like
May be formed. Also, by forming the insulating coating 3 in a state where the U-shaped electrode 2 is provided with a hole, the adhesive force between the U-shaped electrode 2 and the insulating coating 3 can be increased.
The inside of the insulating coating 3 is an electric wire arrangement portion 4, which is arranged close to the electric wire for measuring the voltage by placing the electric wire. The connection terminal 5 is a terminal for connecting to a voltage measuring device. A voltage, which is arranged in the electric wire arrangement section 4 and is shared by the U-shaped electrode 2, is not shown in the figure, for example, a sensor section composed of a Pockels effect element or the like (corresponding to the sensor section 42 shown in FIG. 3). , It is possible to measure the voltage applied to the electric wire. This measurement principle is the same as the conventional one.

By covering the U-shaped electrode 2 with the insulating coating 3, the insulation resistance of the insulating coating 3 is equivalently connected in series to the insulation resistance of the sensor section. It is possible to reduce the influence of humidity due to dust and dew. Therefore, the resistance value of the resistor Rs described above with reference to the equivalent circuit of FIG. Further, in the present invention, since the insulating coating 3 is provided on the U-shaped electrode 2, even when a bare wire is arranged in the wire placement section 4, the insulating coating 3 can safely perform voltage measurement on the bare wire. Become. Also, by forming the insulating coating 3 in a state where the U-shaped electrode 2 is provided with a hole, the adhesive force between the U-shaped electrode 2 and the insulating coating 3 can be increased.

[0010]

As described above, in the voltage measuring device of the present invention, the voltage detecting electrode is covered with the insulating film, so that when measuring the voltage, the voltage detecting electrode is covered with the insulation resistance of the sensor. Since the insulation resistance of the insulation means is connected in series equivalently, dust attached to the sensor as in the past,
It is possible to reduce the influence of humidity due to condensation or the like. As a result, regardless of the environment in which the voltage is measured,
Stable voltage measurement can be performed. Further, by covering the voltage detection electrode with an insulating coating, there is an advantage that voltage measurement can be performed safely even on a bare electric wire.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a hook-shaped electrode serving as a voltage detecting electrode of a voltage measuring device according to an embodiment of the present invention.

FIG. 2 is a front view and a cross-sectional view of a voltage detection electrode according to the present embodiment.

FIG. 3 is an explanatory diagram illustrating the principle of a conventional voltage measuring device.

FIG. 4 is a diagram showing an equivalent circuit of the voltage measuring device shown in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hook-shaped electrode 2 U-shaped electrode 3 Insulation coating 4 Electric wire arrangement part

Claims (1)

[Claims] 1. A voltage measuring device comprising: a voltage detection electrode arranged close to an electric wire; and a sensor unit for detecting a voltage shared by the voltage detection electrode, wherein the voltage detection electrode is covered with insulating means. A voltage measuring device characterized by the above-mentioned.