JPH073343Y2 - Three-phase collective switchgear voltage detector - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a voltage detection device for measuring a ground potential of a high voltage busbar of a gas-insulated switchgear (GIS) of a three-phase package type, especially an electrode for voltage detection. Concerning the structure of.

[Conventional technology]

In many three-phase GIS, especially in the bus room, many three-phase high-voltage bus conductors are arranged in a triangle in a grounded cylindrical airtight container containing insulating gas to maintain the interphase insulation distance. Used. The GIS thus configured measures the ground potential of each high-voltage conductor of each phase, and is a sealed container that faces each high-voltage conductor of each phase while maintaining a predetermined insulation distance and capacitance. A counter electrode that is insulated and supported is provided on this, and this counter electrode is grounded via a voltage dividing capacitor, and the terminal voltage of the voltage dividing capacitor is, for example, an optical voltage converter using a Pockels element (generally called an optical PT). There is known an electric power detection device that uses and measures.

[Problems to be solved by the device]

In the conventional device, the counter electrode has the largest electrostatic capacity with respect to the opposing high-voltage conductor, but at the same time, it also has electrostatic capacity (hereinafter referred to as stray capacitance) with respect to the other two-phase high-voltage conductors. Since, in the three-phase bus, the ground potentials of the high-voltage conductors of each phase have a phase difference of 120 ° with each other, the potential detected at the counter electrode, that is, the terminal voltage of the voltage dividing capacitor, is There is a problem that the ground potential is affected, and therefore the ground potential of the phase to be detected cannot be accurately measured. Therefore, the above-mentioned voltage detecting device is conventionally limited to a means for detecting the presence or absence of the ground potential of the high-voltage conductor, and is used as an instrument transformer for measuring the ground potential of each phase high-voltage conductor with an error of, for example, 1% or less. It was difficult to get the function.

An object of the present invention is to improve the measurement accuracy of the ground potential of each phase high voltage conductor by reducing the stray capacitance.

[Means for Solving the Problems]

In order to solve the above problems, according to the present invention, the relative ground potentials of the three-phase high-voltage conductors arranged in a triangle in a cylindrical hermetic container are set to a predetermined insulation distance and electrostatic capacitance for each high-voltage conductor. In the case of measuring the voltage divided by the electrostatic capacity by detecting the counter electrode which is held by and is insulated and supported by the closed container, the predetermined insulation distance is substantially equal to the two high voltage conductors. It is assumed that the shield electrode is composed of a cylindrical ground conductor arranged in a triangle while maintaining an insulation distance.

[Action]

In the above means, the shield electrodes are arranged in a triangle while maintaining an almost equal insulation distance with respect to two of the high voltage conductors arranged in a triangle, so that the capacitive coupling between the high voltage conductor of each phase and the shield electrode is achieved. Since it becomes denser and conversely the stray capacitance to the counter electrode is reduced, the influence of the ground potential of the other-phase high-voltage conductor is greatly reduced, and the ground potential of the opposing high-voltage conductor can be accurately measured.

〔Example〕

 The present invention will be described below based on embodiments.

FIG. 1 is a sectional view showing an apparatus according to an embodiment of the present invention. In the figure, an insulating gas 2 such as SF ₆ gas and cylindrical high-voltage conductors 3A, 3B, 3C arranged in a triangle are housed in a grounded cylindrical closed container 1 while maintaining a mutual insulation distance between them, Form a three-phase batch type bus room. High voltage conductors 3A, 3B,
Disc-shaped counter electrodes 4A, 4B, and 4C facing each 3C are provided so as to project from the closed container 1 side so as to maintain a ground insulation distance d between them and the high-voltage conductor and the counter electrode. A capacitance C ₁ is formed between them. The counter electrodes 4A, 4B, 4C are grounded via the airtight terminals 5A, 5B, 5C and the voltage dividing capacitor 9 having electrostatic capacity C ₂ (only one place is shown in the figure in a simplified manner), and the voltage dividing capacitor 9 The terminal voltage is measured by the measuring unit 10.

In the figure, the three-lobed broken line 100 is a curve showing the positions separated from the high-voltage conductors 3A, 3B, 3C by the ground insulation distance d,
Cylindrical shield electrode 6a at two points that touch the curve 100
b, 6bc, 6ac are provided. The shield electrode is made of a cylindrical conductor having a diameter close to that of the high-voltage conductor, and the length in the direction along the high-voltage conductor is more than twice the insulation distance d from the ground. It is held at ground potential by being electrically connected to the container 1. The shield electrode thus configured has a triangular arrangement in which two of the high-voltage conductors arranged in a triangle are opposed to each other while maintaining an insulation distance d from the ground. It tightly capacitively couples two high-voltage conductors holding the insulation distance d, and functions as a shield electrode for bypassing the charging current from the high-voltage conductors to the ground side. Thus, for example, for the counter electrode 4C, the high voltage conductors 3A and 3B
Stray capacitance and its charging current are
And 6ac decrease due to the shielding function of the counter electrode 4C, so that the counter electrode 4C has a capacitance C ₁ between the high-voltage conductor 3C and a capacitance C _{2 of the} voltage dividing capacitor 9 (including the ground capacitance of the counter electrode). The voltage determined by the voltage division ratio to the voltage dividing capacitor is applied to the voltage dividing capacitor, and its terminal voltage is measured by the measuring unit 10 to eliminate the influence of the ground potential of the other phase high voltage conductor.
It becomes possible to accurately measure the ground potential of 3 C, and for example, it is possible to obtain a voltage detecting device having a function as a transformer for an instrument having a measurement accuracy with a measurement error of 1% or less.

FIG. 2 is a cross-sectional view showing a device according to another embodiment of the present invention, in which triangularly arranged high voltage conductors 3A, 3B and 3C are provided with disk-shaped electrodes 7A, 7B and 7C, respectively, and face each other. Electrode 4
It differs from the above-mentioned embodiment in that A, 4B, 4C are arranged in pockets 8A, 8B, 8C projecting toward the outside of the closed container so as to maintain a ground insulation distance d. . As a result, the curve indicating the position for holding the ground insulation distance d with respect to the high-voltage conductors 3A, 3B, 3C changes as shown by the broken line 101, but the shield electrodes 6ab, 6bc, By arranging 6ac, the function of the shield electrode with respect to the counter electrode can be exhibited more highly.

[Effect of device]

As described above, the present invention is configured such that the cylindrical shield electrodes are arranged in a triangle shape while maintaining substantially the same ground insulation distance with respect to two high voltage conductors arranged in a triangle in a cylindrical closed container. As a result, the shielding electrode, which faces the high-voltage conductor and is insulated and supported by the closed container, provides the shielding function of bypassing the stray capacitance from the other-phase high-voltage conductor and its charging current to the ground side. As a result, the voltage measurement error due to the stray capacitance, which has been a problem in the prior art, is eliminated, and therefore the detector having the function as an instrument transformer capable of measuring the ground potential of each phase high-voltage conductor within a measurement error of 1%. An electric device can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing an apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view showing an apparatus according to another embodiment. 1 ... Airtight container, 2 ... Insulating gas, 3A, 3B, 3C ... Triangularly arranged high voltage conductors, 4A, 4B, 4C ... Counter electrodes, 6ab, 6bc,
6ac ... shielding electrode, d ... insulation distance to ground, 8A, 8B, 9C ...
… Electrode (high-voltage side), 9 ... Voltage dividing capacitor, 10 ... Measuring unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Mutsumi Tsutsumi 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (56) References JP-A-60-260863 (JP, A)

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A three-phase high-voltage conductor, which is arranged in a triangle in a cylindrical hermetically sealed container, holds the relative ground potential in each of the high-voltage conductors while maintaining a predetermined insulation distance and capacitance. In a device for detecting a voltage divided by an electrostatic capacity by detecting it with an opposite electrode supported by insulation, a triangular arrangement is provided with an insulation distance substantially equal to the predetermined insulation distance with respect to the two high voltage conductors. A three-phase collective switchgear voltage detecting device comprising a shield electrode made of a cylindrical grounded conductor.