JP2001027653A - Capacitor potential divider - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive and compact capacitor potential divider that can eliminate the need for providing a plurality of capacitors with a large withstand voltage being provided in a transformer for preventing electrostatic breakdown due to steep surge penetration, and can stabilize secondary-side capacitance. SOLUTION: In the capacitor potential divider, a floating electrode 23 is provided while the floating electrode opposes a high-voltage conductor 22 being accommodated coaxially with a ground container 21, and a dielectric film 25b is provided at a part of a ground electrode 24 being mounted to the ground container 21. In the dielectric film 25b, conductive films 25e and 25f being conductively brought into contact with the ground and floating electrodes 24 and 23 at least at one place are formed on both surfaces. A lead wire 28 is provided between a floating electrode 23 and a voltage detection terminal in a transformer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor voltage divider mounted on a gas-insulated electric device.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing the structure of a conventional capacitor voltage divider.
-75795. In FIG. 4, 1
Is a high-voltage conductor accommodated along the axis of the ground container, 2 is a high-voltage conductor, and 2 is a high-voltage conductor.
And a plurality of through holes formed in the center of the floating electrode 3 in the thickness direction, and 5 are provided at both ends of the through hole 4 of the floating electrode 3. Insulated member, 6 is ground container 1
And 7 are end electrodes provided to face the mounting bracket 4.

Reference numeral 8 denotes a tightening screw, which penetrates through the end electrode 7, the insulating member 5, the floating electrode 3, and the insulating member 5 and is fastened to the mounting bracket 6. Since the insulating member 5 is interposed between the floating electrode 3 and the grounding container 1, the floating electrode 3 is held electrically floating. Reference numeral 9 denotes a connection port provided at a predetermined position of the grounded container, and 10 denotes a transformer provided outside the grounded container 1. A lead wire 11 is connected to the floating electrode 3 and the transformer 10. A capacitor (not shown) is provided inside the transformer 10, and one of the capacitors is connected to the lead wire 11 and the other is connected to the grounded container of the transformer 9.

In the capacitor voltage divider configured as described above, the capacitance formed between the high-voltage conductor 2 and the floating electrode 3 (hereinafter referred to as the primary-side capacitance) and the floating electrode 3 This is a state in which the capacitance between the grounded transformer 10 and the grounded container (hereinafter referred to as the secondary-side capacitance) is in series. For this reason, the voltage applied between the grounding container 1 and the high-voltage conductor 2 is divided by the primary-side capacitance and the secondary-side capacitance, and a divided voltage is induced in the floating electrode 3. Is done. In order to improve the accuracy of the divided voltage, it is necessary to stabilize the primary-side capacitance and the secondary-side capacitance.

FIG. 5 is a cross-sectional view showing the configuration of another conventional capacitor voltage divider. A similar configuration is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-134573. In FIG. 5, 1 is a grounded container, 2 is a high voltage conductor accommodated along the axis of the grounded container, and 12 is a ground electrode provided on the grounded container. Reference numeral 13 denotes an insulator provided in contact with the ground electrode 12, and reference numeral 14 denotes a floating electrode provided so as to sandwich the insulator 13, and forms a secondary-side capacitance with the ground electrode 12. Also in this case, in order to obtain a divided voltage value with good detection accuracy, it is necessary to stabilize the primary-side capacitance and the secondary-side capacitance between the high-voltage conductor 2 and the floating electrode 13.

[0006]

In the conventional capacitor voltage divider shown in FIG. 4 as described above, since the secondary capacitance and the floating electrode 3 are connected by the lead 11, Inductance is formed,
Further, an inductance structurally formed by a lead wire or the like of the secondary capacitance intervenes in series. For this reason,
When a steep surge is applied, a high voltage is generated between both ends of the lead wire, that is, between the floating electrode 3 and the grounding container 1 and between the secondary-side capacitance and the container of the transformer 10, and dielectric breakdown occurs. There was a problem. In order to avoid this dielectric breakdown, a plurality of capacitors having a large withstand voltage value may be connected in parallel to the transformer 10 to reduce the inductance. However, in this case, the installation cost of the capacitors is increased, and a large installation space is required. There was a problem that it became necessary.

Further, the conventional capacitor voltage divider shown in FIG. 5 has a structure in which an insulator 13 is interposed between a ground electrode 12 and a floating electrode 14, and the two
A secondary capacitance is formed. For this reason, as shown in FIG. 6, which is a cross-sectional view showing a main part of FIG. 5, when the assembly accuracy and the processing accuracy are poor, a gap is formed between the ground electrode 12 and the insulator 13. When a gap is formed, a new capacitance is generated in the gap, and the secondary-side capacitance between the floating electrode 3 and the ground electrode 12 changes, so that there is a problem that an accurate divided voltage cannot be obtained. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a plurality of capacitors having a large withstand voltage provided in a transformer for preventing electrostatic breakdown due to a sharp surge intrusion. It is an object of the present invention to provide a capacitor voltage divider which can eliminate the necessity of providing a capacitor, is inexpensive, and can be reduced in size. Another object of the present invention is to provide a capacitor voltage divider capable of stabilizing the secondary-side capacitance.

[0009]

In a capacitor voltage divider according to the present invention, a high-voltage conductor accommodated along the axis of a grounded container, a floating electrode provided opposite to the high-voltage conductor, and a grounded container. A dielectric film is provided between the ground electrode and the floating electrode connected thereto, and has a conductive film formed on both surfaces thereof in conductive contact with the ground container and the floating electrode at at least one place.

[0010] Further, a grounding container in a pipe portion of the gas insulated switchgear, a high-voltage conductor accommodated along an axis of the grounding container,
A floating electrode provided between the high-voltage conductor and the grounding container facing the high-voltage conductor, provided between the grounding electrode and the floating electrode attached to the grounding container,
A dielectric film formed on both sides with a conductive film that is in conductive contact with the ground electrode and the floating electrode at at least one location, respectively; a capacitance between the high-voltage conductor and the floating electrode; And a deriving means for deriving a divided voltage induced in the floating electrode by being divided by the capacitance between the floating electrodes.

[0011] Also, a ground container in a pipe section of the gas insulated switchgear, a high-voltage conductor housed along the axis of the ground container,
A concave portion provided in the grounding container, a floating electrode provided in the concave portion and provided at substantially the same height as the grounding container facing the high-voltage conductor, and between the ground electrode and the floating electrode attached to the concave portion. A dielectric film having a conductive film formed on both sides thereof, the conductive film being in conductive contact with the ground electrode and the floating electrode at at least one position, a capacitance between the high-voltage conductor and the floating electrode, and a floating electrode and the ground. And a deriving means for deriving a divided voltage induced in the floating electrode by being divided by the capacitance between the electrode and the electrode.

Still further, the dielectric film has an opening, and conductive films formed on both sides of the dielectric film are provided in a region between an outer peripheral end of the dielectric film and a periphery of the opening. It is.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a sectional view showing a configuration of a capacitor voltage divider according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 21 denotes a grounded container in which a pipe portion of the gas insulated switchgear is grounded; 22, a high-voltage conductor made of aluminum or the like accommodated along the axis of the grounded container 21;
Reference numeral 23 denotes a cylindrical floating electrode made of aluminum or the like, which is provided between the grounding container 21 and the high-voltage conductor 22 so as to face the high-voltage conductor 22 and is attached to the grounding container 21 via an insulating member (not shown). I have. Reference numeral 24 denotes a plate-like ground electrode, which has the same width as the floating electrode 23 and is attached by a fastener (not shown) or welding (not shown) so as to face the floating electrode 23 and closely adhere along the inner peripheral surface of the ground container 21. .

Reference numeral 25 denotes an intermediate member provided between the floating electrode 23 and the ground electrode 24, which is made of polyethylene terephthalate, fluorine resin or the like, has an outer diameter larger than that of the floating electrode, and has an opening through which a lead wire 28 described later passes. Dielectric film 25b having a portion 25a, an outer peripheral end 25c of the dielectric film 25b, and an opening peripheral portion 25c.
d, conductive films 25e and 25f made of aluminum or the like formed on both surfaces of the region by vapor deposition or the like.
The conductive films 25e and 25f are formed so as to make conductive contact with the floating electrode 23 or the ground electrode 24 at at least one place. However, the floating electrode 23 is formed by the dielectric film 25b interposed therebetween. 21 and is electrically floating. Reference numeral 26 denotes a connection port provided in the grounding container 21, and reference numeral 27 denotes a transformer provided outside the grounding container 21 so as to face the floating electrode 23. Reference numeral 28 denotes a lead wire which is connected to a floating electrode 23 and a voltage detection terminal (not shown) provided on the transformer 27.

FIG. 2A is a radial sectional view of a main part of FIG. 1, and FIG. 2B is an explanatory view of a main part of FIG. 2A. This shows a case where a gap is formed between them. Since at least one conductive contact is formed between the ground electrode 24 and the conductive film 25f and between the floating electrode 23 and the conductive film 25e, they have the same potential. Therefore, the floating electrode 23 and the grounding container 2
1 between the conductive film 25e and the conductive film 2e.
5f, which is determined only by the thickness of the dielectric film 25b and the areas of the conductive films 25e and 25f, and the gap does not change the secondary-side capacitance.
Similarly, when a gap is formed between the floating electrode 23 and the conductive film 25e, the secondary-side capacitance does not change due to the gap. Therefore, a stable secondary-side capacitance can be obtained without depending on the processing accuracy and the assembly accuracy of the electrode.

The ground electrode 24 may be a thin film made of aluminum or the like, or may be provided partially along the inner peripheral surface of the ground container 21, and a conductive contact is formed at at least one place with the ground container 21. If so, the same operation and effect as described above can be obtained.

High voltage conductor 22 and floating electrode 23
And the secondary-side capacitance between the floating electrode 21 and the ground electrode 24 is in series. Therefore, the voltage applied between the high-voltage conductor 22 and the grounding container 21 is divided by the primary-side capacitance and the secondary-side capacitance, and a divided voltage is induced on the floating electrode 23. You. The induced divided voltage is led by a lead wire 28 to a voltage detection terminal (not shown) in the transformer 27.

The secondary-side capacitance is the floating electrode 2
3 and the ground electrode 24 at least at one place, respectively, are formed without passing through a lead wire on the dielectric film 25b formed on both surfaces of the dielectric film 25b, so that the floating electrode 23 and the ground electrode 24 are grounded. No inductance is formed with the electrode 24. Therefore, when a steep surge is applied, it is possible to prevent a high voltage from being generated between both ends of the lead wire 28, that is, between the floating electrode 23 and the ground electrode 24 and the container of the transformer 27. It is possible to eliminate the need for a plurality of capacitors connected in parallel and having a large withstand voltage as secondary capacitances configured to reduce the inductance of the device 10 as much as possible. Can be.

The outer peripheral end 2 of the dielectric film 25b
The conductive film 25 is formed in a region between the opening 5c and the opening peripheral portion 25d.
Since e and 25f are formed, the insulation distance between the conductive films 25e and 25f in the outer peripheral end portion 25c and the opening peripheral portion 25d can be increased.

Embodiment 2 FIG. 3 is a sectional view showing a configuration of a capacitor voltage divider according to Embodiment 2 of the present invention.
3, the same reference numerals as those shown in FIG. 1 denote the same or equivalent parts, and a description thereof will be omitted.
Reference numeral 29 denotes a concave portion provided in the grounding container 21. A transformer 27 is mounted on the outside, and a floating electrode 30, an intermediate member 32, and a ground electrode 31 described later are accommodated on the inside. Three
Numeral 0 denotes a disk-shaped floating electrode made of aluminum or the like, which is provided at substantially the same height as the inner surface of the ground container 21 so as to face the high-voltage conductor 22 and is attached to a ground electrode 31 described later via an insulating member (not shown). Have been. Reference numeral 31 denotes a ground electrode attached to the concave portion 29, which is attached by a fastener (not shown) or welding.

Reference numeral 32 denotes an intermediate member provided between the floating electrode 30 and the ground electrode 31. The intermediate member 32 has an outer diameter larger than the floating electrode made of polyethylene terephthalate, fluororesin, or the like, and an opening 32a through which a lead wire 33 described later passes. And a conductive film 32e and 32f made of aluminum or the like formed on both surfaces of a region between the outer peripheral end portion 32c and the opening peripheral portion 32d of the dielectric film 32b by vapor deposition or the like. . In addition, each of the conductive films 32e and 32f is a floating electrode 3
Although the conductive contact is formed at least at one position with the zero or the ground electrode 31, the floating electrode 30 is electrically floating from the ground container 21 by the interposition of the dielectric film 32b. Reference numeral 33 denotes a lead wire for deriving a divided voltage induced in the floating electrode, which is connected to the floating electrode 30 and a voltage detection terminal (not shown) provided on the transformer 27.

In the capacitor voltage divider constructed as described above, the conductive film 32 is formed on both surfaces of the dielectric film 32f.
e and 32f, when a gap is formed between the ground electrode 31 and the conductive film 32e, the space between the ground electrode 31 and the conductive film 32e and the space between the floating electrode 30 and the conductive film 32f are respectively formed. Since at least one conductive contact is formed, the potential is equal. For this reason, the secondary-side capacitance between the floating electrode 30 and the grounding container 21 becomes the capacitance formed between the conductive films 32e and 32f, and the thickness of the dielectric film 32b and the conductive film 3
It depends only on the area of 2e, 32f, and 2
The secondary capacitance does not change. Similarly, when a gap is formed between the floating electrode 30 and the conductive film 32f, the secondary-side capacitance due to the gap does not change. Therefore, a stable secondary-side capacitance can be obtained without depending on the processing accuracy and the assembly accuracy of the electrode.

High voltage conductor 22 and floating electrode 30
And the secondary-side capacitance between the floating electrode 30 and the ground electrode 31 is in series. Therefore, the voltage applied between the high-voltage conductor 22 and the grounding container 21 is divided by the primary-side capacitance and the secondary-side capacitance, and a divided voltage is induced in the floating electrode 30. You. The induced divided voltage is led to a voltage detection terminal (not shown) in the transformer 27 by the lead wire 33.

The secondary-side capacitance is equal to the floating electrode 3
The conductive film 32e, 32f, which is in conductive contact with at least one of each of the conductive film 32 and the ground electrode 31, is formed on the dielectric film 32b formed on both surfaces without a lead wire. No inductance is formed with the electrode 31. Therefore, when a steep surge is applied, it is possible to prevent a high voltage from being generated between both ends of the lead wire 33, that is, between the floating electrode 30 and the ground electrode 31 and the container of the transformer 27. It is possible to eliminate the need for a plurality of capacitors connected in parallel and having a large withstand voltage as secondary capacitances configured to reduce the inductance of the device 10 as much as possible. Can be.

The outer peripheral end 3 of the dielectric film 32b
The conductive film 32 is formed in a region between the opening 2c and the periphery 32d of the opening.
Since e and 32f are formed, the insulation distance between the conductive films 32e and 32f in the outer peripheral end portion 32c and the opening peripheral portion 32d can be increased.

Further, in the second embodiment, since the floating electrode is provided in the concave portion provided in the grounded container, it is possible to obtain a capacitor voltage divider which can be easily attached and detached as compared with the first embodiment. The high-voltage conductor may be a three-phase high-voltage conductor, and has the same operation and effect as described above.

[0027]

Since the present invention is configured as described above, it has the following effects.

Between the ground container and the floating electrode,
By providing a dielectric film having conductive films formed on both sides thereof in at least one place in contact with the grounding container and the floating electrode, the distance between the grounding container and the conductive film and between the floating electrode and the conductive film are respectively increased. The potential on the secondary side between the floating electrode and the grounded container can be equal to the capacitance formed between the two conductive films. Even when a gap is formed between the conductive film or the floating electrode and the conductive film, a stable secondary-side capacitance can be obtained.

A floating electrode is provided between the high-voltage conductor and the grounding container facing the high-voltage conductor housed along the axis of the grounding container, and between the ground electrode attached to the grounding container and the floating electrode. A dielectric film having conductive films formed on both sides thereof in at least one place in contact with the ground electrode and the floating electrode; providing a capacitance between the high-voltage conductor and the floating electrode; By providing a deriving means for deriving a divided voltage induced on the floating electrode by being divided by the capacitance between the floating electrode and the ground electrode, the distance between the ground electrode and the conductive film and the distance between the floating electrode and the conductive film are provided. Each of them can be set at the same potential, so that a secondary-side capacitance between the floating electrode and the ground electrode is formed between both conductive films. It is possible to make the capacity, even if could gap or between the floating electrode and the conductive film between the ground electrode and the conductive film, it is possible to obtain stable secondary capacitance. In addition, since the secondary-side capacitance is formed of a dielectric film having conductive films formed on both sides thereof in conductive contact with the ground electrode and the floating electrode at at least one place, the floating electrode and the ground electrode No inductance is formed between them. For this reason, when a steep surge is applied, it is possible to prevent a high voltage from being generated at both ends of the deriving means, and a plurality of parallel-connected secondary-side capacitances configured to minimize the inductance as in the related art. It is possible to eliminate the need for a capacitor having a high withstand voltage value, which is connected to the device, thereby reducing the cost and size.

A floating electrode is provided at substantially the same height as the grounding container, facing the high-voltage conductor accommodated along the axis of the grounding container in a recess provided in the grounding container. Provided between the electrodes, a dielectric film formed on both sides of a conductive film that is in conductive contact with the ground electrode and the floating electrode at at least one location, and a capacitance between the high-voltage conductor and the floating electrode, By providing a deriving means for deriving a divided voltage induced in the floating electrode by dividing the voltage by the capacitance between the floating electrode and the ground electrode, it is possible to provide between the ground electrode and the conductive film and between the floating electrode and the conductive electrode. The potential between the floating electrode and the ground electrode can be set to the same potential between the floating electrode and the ground electrode. Between the ground electrode and the conductive film or between the floating electrode and the conductive film, a stable secondary-side capacitance can be obtained. Obtainable. In addition, since the secondary-side capacitance is formed of a dielectric film having conductive films formed on both sides thereof in conductive contact with the ground electrode and the floating electrode at at least one place, the floating electrode and the ground electrode No inductance is formed between them. For this reason, when a steep surge is applied, it is possible to prevent a high voltage from being generated at both ends of the deriving means, and a plurality of parallel-connected secondary-side capacitances configured to minimize the inductance as in the related art. It is possible to eliminate the need for a capacitor having a high withstand voltage value, which is connected to the device, thereby reducing the cost and size.

Further, the dielectric film has an opening, and a conductive film formed on both surfaces of the dielectric film is applied to a region between the outer peripheral end of the dielectric film and the periphery of the opening, whereby: The insulation distance between the two conductive films can be increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a capacitor voltage divider according to Embodiment 1 of the present invention.

FIGS. 2A and 2B are explanatory views of main parts of FIG. 1, wherein FIG. 2A is a radial cross-sectional view of the main parts of FIG. 1, and FIG.
It is explanatory drawing which shows the principal part of.

FIG. 3 is a cross-sectional view illustrating a configuration of a capacitor voltage divider according to Embodiment 2 of the present invention.

FIG. 4 is a cross-sectional view showing a configuration of a conventional capacitor voltage divider.

FIG. 5 is a cross-sectional view showing the configuration of another conventional capacitor voltage divider.

FIG. 6 is a sectional view showing a main part of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Grounding container 22 High voltage conductor 23, 30 Floating electrode 24, 31 Grounding electrode 25a, 32a Opening 25b, 32b Dielectric film 25c, 32c Outer peripheral end 25d, 32d Opening peripheral 25e, 25f, 32e, 32f Conductive film 29 recess 28,33 lead wire (lead-out means)

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Yoshitaka Habuchi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 2G025 AA05 AB07

Claims (4)

[Claims] 1. A high-voltage conductor accommodated along an axis of a grounded container, a floating electrode provided to face the high-voltage conductor, and a high-voltage conductor provided between the grounded container and the floating electrode, A capacitor voltage divider, comprising: a dielectric film having conductive films formed on both sides thereof in conductive contact with at least one of the grounding container and the floating electrode. 2. A grounding container in a pipe section of a gas insulated switchgear, a high-voltage conductor accommodated along an axis of the grounding container, the high-voltage conductor facing the high-voltage conductor, and the grounding container. A floating electrode provided between the floating electrode and a ground electrode attached to the ground container and the floating electrode, wherein the conductive film is in conductive contact with the ground electrode and the floating electrode at at least one place, respectively. Is divided by the dielectric film formed on both sides, the capacitance between the high-voltage conductor and the floating electrode, and the capacitance between the floating electrode and the ground electrode, and the floating is performed. And a deriving means for deriving a divided voltage induced in the electrode. 3. A ground container in a pipe section of the gas insulated switchgear, a high-voltage conductor accommodated along an axis of the ground container, a concave portion provided in the ground container, and a concave portion provided in the concave portion; A floating electrode provided at substantially the same height as the ground container facing the high-voltage conductor; provided between the ground electrode and the floating electrode attached to the concave portion; the ground electrode and the floating electrode; A dielectric film formed on both sides with a conductive film that is in conductive contact with at least one location each; a capacitance between the high-voltage conductor and the floating electrode; and a capacitance between the floating electrode and the ground electrode. And a deriving means for deriving a divided voltage induced at the floating electrode by being divided by the capacitance of the capacitor. 4. The dielectric film has an opening, and conductive films formed on both surfaces of the dielectric film are applied to a region between an outer peripheral end of the dielectric film and a periphery of the opening. The capacitor voltage divider according to any one of claims 1 to 3, wherein: