JP2002058119A - Gas insulated switchgear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas insulated switchgear that has high insulation reliability with respect to metallic foreign materials, even if the switchgear is reduced in size. SOLUTION: This switchgear is provided with a metal container 2 of a cylindrical shape, in which an insulating gas is sealed and a conductor 1 for conducting that, is passed through the metal container 2 and supported by an insulating spacer 3. The metal container 2 has an insulating painted part 6, that is formed in a range within 180 degrees of the central angle in the direction of the circumference of the inside of the metal container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas insulated switchgear used for power equipment, and more particularly to a gas insulated switchgear having improved insulation reliability.

[0002]

2. Description of the Related Art At present, a large number of gas insulated switchgear using SF6 (sulfur hexafluoride) gas as an insulating gas are installed in an electric power system. The structure of a conventional general gas insulated switchgear is as shown in FIG. That is, a high-voltage conductor 1 for energization having a round rod shape or a cylindrical shape is inserted into a metal container 2 having a cylindrical shape or an elliptical cylindrical shape, and an insulating spacer 3 is attached to the high-voltage conductor 1. The outer edge of 3 is attached to the metal container 2 by bolts and nuts. As the insulating gas 4 sealed in the metal container 2, SF6 gas having excellent insulating performance is widely used.

[0003] Such gas insulated switchgear has widened its application range and is now the mainstream of gas insulated switchgear in substations and power plants. Gas insulated switchgear, 1100kV
Application to class systems is also planned, and higher voltages and higher capacities are being promoted.

[0004] Substations using these large gas insulated switchgears form the basis of social electric energy,
While high reliability is required, application to underground substations in urban areas and reduction in size from the viewpoint of economic efficiency are also desired. In order to satisfy these requirements, there is a demand for a gas-insulated switchgear having higher insulation reliability than conventional and capable of withstanding use at a high voltage.

[0005]

The gas-insulated switchgear that has been frequently used has several problems.
As one of them, by filling with a gas having a very excellent insulating performance under pressure, it is possible to greatly reduce the size compared with the air insulation, but there is a metal foreign matter of, for example, about several mm in the metal container 2. It is known that the insulation performance between the high-voltage conductor 1 and the metal container 2 is significantly reduced just by performing the operation.

The metal foreign matter reciprocates between the high-voltage conductor 1 and the metal container 2 under the operating voltage as shown in a metal foreign matter behavior locus 5 in FIG. In such a situation, when the metal foreign matter reaches the high-voltage conductor 1, the possibility of dielectric breakdown occurring in the insulating space between the high-voltage conductor 1 and the metal container 2 increases. The height at which the metallic foreign matter rises and floats depends on the electric field strength on the inner surface of the metal container 2, and in order to suppress the behavior of the metallic foreign matter, it is necessary to keep the electric field intensity on the inner surface of the metallic container 2 low.
In order to lower the electric field strength on the inner surface, it is necessary to increase the diameter of the metal container 2.

As described above, in the conventional gas insulated switchgear, it is difficult to reduce the size and at the same time to increase the reliability in order to prevent the metal foreign matter from reciprocating in the gas insulated space. Therefore, a method of applying an insulating coating to the inner surface of the metal container 2 has been studied as a means for suppressing the behavior of the metal foreign matter. This is because, by providing an insulating layer between the inner surface of the metal container 2 and the metal foreign matter, the supply of electric charge to the metal foreign matter is suppressed, and the metal foreign matter behavior suppressing effects such as the rise of the metal foreign matter standing electric field and the reduction of the foreign matter floating height are reduced. Can be expected.

As an effect of the insulating coating, FIG. 5 shows a floating characteristic of the metal foreign matter on the insulating coating electrode. When the insulating coating is applied, the floating electric field is about twice as large as that in the case of the bare electrode, and it can be seen that the behavior of the foreign metal is suppressed. Thus, it is not necessary to suppress the electric field strength on the inner surface of the metal container, and the device can be downsized.

[0009] However, the insulation coating may have an adverse effect on the detection of foreign metal. That is, when the gas insulated switchgear is shipped, a withstand voltage test is generally performed for the purpose of detecting and removing metal foreign matter remaining during assembly. In this method, an AC commercial frequency voltage is applied, residual metal foreign matter is detected by partial discharge measurement, ultrasonic measurement, etc., and in some cases, the gas insulated switchgear is disassembled to remove the residual metal foreign matter. However, when the insulating coating is applied, the behavior of the metallic foreign matter is suppressed, so that the residual metallic foreign matter may not be detected or found. Therefore, an object of the present invention is to provide a gas insulated switchgear having high insulation reliability with respect to metal foreign substances even if it is miniaturized.

[0010]

In order to achieve the above-mentioned object, a first aspect of the present invention provides a metal container having a tubular shape and filled with an insulating gas, and a metal container inserted into the metal container and supported by an insulating spacer. And a conductor for energization, and an insulating coating portion formed within a range of a central angle of 180 degrees or less in a circumferential direction of an inner surface of the metal container.

[0011] In the gas insulated switchgear according to the first aspect of the present invention having the above structure, a painted portion is provided on the inner surface of the metal container.
Both unpainted parts are present. Metallic foreign matter generally collects on the bottom surface of the metal container. For this reason, when it is necessary to detect metal foreign matter, the unpainted part of the metal container is placed on the bottom surface of the metal container to facilitate detection. Conversely, when it is necessary to suppress the behavior of the metal foreign matter, The painted part can be arranged on the bottom of the container. Thereby, both the suppression of the behavior of the metal foreign matter and the detection can be effectively performed.

According to a second aspect of the present invention, in the gas insulated switchgear according to the first aspect, the insulating coating portion is disposed on a top surface during a withstand voltage test and is disposed on a bottom surface during a commercial operation.
In the gas insulated switchgear according to the second aspect of the present invention having the above-described configuration, during the withstand voltage test, the portion on which the inner surface is not coated is disposed on the bottom surface, so that the detection of metal foreign matter becomes easy. In general, a gas-insulated switchgear is subjected to a withstand voltage test in a factory to detect a defective assembly, a defective part, a residual metal foreign matter, and the like. In the test of the commercial frequency voltage, if any metallic foreign matter remains, the foreign matter behaves, and partial discharge and ultrasonic waves are detected and found. At this time, it is desirable to dispose the bottom surface of the non-painted portion where the detection of metal foreign matter is easy. Here, the gas section confirmed to be free of metallic foreign matter is sent to the site without opening to the atmosphere as much as possible to prevent the metallic foreign matter from being mixed.

Although many of the metallic foreign substances are mixed during the assembling, there are rarely foreign metallic substances and the like generated during commercial operation. Metallic foreign matter during assembly can be easily detected by arranging the top surface of the painted part, but when the metallic foreign matter that falls afterwards falls on the bottom of the metal container, if the area is coated with insulation, its behavior is suppressed. It becomes possible. Therefore, at the time of commercial operation, it is desirable to arrange the bottom surface of the portion where the inner surface is painted. According to the second aspect of the present invention, it is possible to suppress the behavior of the metallic foreign matter generated after the start of the commercial operation and improve the reliability.

According to a third aspect of the present invention, in the gas insulated switchgear according to the first aspect, the insulating coating portion is formed after the withstand voltage test is completed. According to the present invention, without coating the inner surface of the metal container until the withstand voltage test, the detection of metal foreign matter is facilitated, and after confirming that there is no metal foreign matter, the inner surface, especially the bottom portion, is checked before commercial operation. Apply paint. As a result, the behavior with respect to the metal foreign matter that remains by any chance or generated after the start of commercial operation can be suppressed, and the reliability can be improved.

According to a fourth aspect of the present invention, in the gas insulated switchgear according to the first aspect, the insulating coating portion is formed of an epoxy resin paint or a fluororesin paint.

As shown in FIG. 5, it has been experimentally confirmed that the use of an epoxy resin-based paint or a fluororesin-based paint results in a floating electric field that is about twice or more that of a bare metal.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. Note that the same components as those of the conventional device shown in FIG. 5 are denoted by the same reference numerals, and description thereof is omitted.

FIG. 1 is a configuration diagram of a gas insulated switchgear according to a first embodiment. That is, the configurational feature of the first embodiment is that the insulating coating 6 is applied only to a limited area on the inner surface of the metal container 2. The inner surface of the metal container 2 whose circumferential central angle θ is within 180 degrees is painted. As a material of the insulating coating 6, an epoxy resin-based paint or a fluorine resin-based paint, which has been confirmed to suppress the floating electric field of the metallic foreign matter, is used.

In this embodiment, a painted portion and an unpainted portion exist on the inner surface of the metal container 2. The metal foreign matter generally exists on the bottom surface of the metal container 2. For this reason, when it is necessary to detect metal foreign matter, the unpainted portion of the metal container 2 is arranged on the bottom surface of the metal container 2 to facilitate detection, and when it is necessary to suppress the behavior of the metal foreign matter, The painted portion of the metal container 2 can be arranged on the bottom surface of the container 2. As a result, a gas-insulated switchgear that easily performs both the behavior suppression and the detection of the metallic foreign matter is obtained.

FIG. 2 is a configuration diagram of a gas insulated switchgear according to a second embodiment. That is, the structural features of this embodiment are that the position of the portion where the insulating coating 6 is applied is the case of the commercial operation (FIG. 2B) and the case of the withstand voltage test (FIG. 2B).
(A)).

In this embodiment, at the time of the withstand voltage test, the portion on which the insulating coating 6 is not applied is arranged on the bottom surface of the metal container 2, so that the detection of the metal foreign matter becomes easy. With this arrangement, detection of partial discharge and ultrasonic waves in the event that metallic foreign matter remains in the test of the commercial frequency voltage becomes easy. When the metal foreign matter falls on the bottom surface of the metal container 2 after the start of the commercial operation, the behavior can be suppressed if the insulating coating 6 is applied to the area. Therefore, during commercial operation, the portion where the inner surface is painted is arranged on the bottom surface. Thereby, insulation reliability can be improved.

Next, FIG. 3 shows a configuration diagram of a gas insulated switchgear according to a third embodiment. That is, in this embodiment, an opening 7 for injecting an insulating coating agent into the bottom of the metal container 2 is provided.
Is provided.

The gas insulated switchgear of this embodiment facilitates the detection of residual metal foreign matter without coating the inner surface of the metal container 2 until the withstand voltage test, and after confirming that there is no residual metal foreign matter. Before the commercial operation, paint the inner surface, especially the bottom. As shown in FIG. 3, an insulating coating agent injection port 7 is provided on the bottom surface of the metal container 2, and the insulating coating agent is injected from here,
By applying a coating to the bottom surface of the metal container 2, the behavior with respect to the metal foreign matter that remains by any chance or generated after the start of commercial operation can be suppressed, and the reliability can be improved.

[0024]

As described above, according to the present invention, the portion where the insulating coating of the metal container is applied is limited, and the non-painted portion is disposed on the bottom surface during the withstand voltage test to detect the metal foreign matter without suppressing the behavior. By reducing the size of the metal container by reducing the size of the metal container by reducing the size of the metal container, it is possible to effectively control the behavior of the metal foreign material and detect it effectively even when the metal container is downsized. It is possible to provide a highly insulated switchgear.

[Brief description of the drawings]

FIG. 1 shows a configuration of a gas insulated switchgear according to a first embodiment of the present invention, wherein (a) is a cross-sectional view parallel to an axis of a metal container,
(B) is sectional drawing which follows the bb line | wire of (a).

FIGS. 2A and 2B show the configuration of a gas insulated switchgear according to a second embodiment of the present invention, wherein FIG. 2A shows a withstand voltage test and FIG. 2B shows a commercial operation.

FIG. 3 shows a configuration of a gas insulated switchgear according to a third embodiment of the present invention, wherein (a) is a cross-sectional view parallel to the axis of a metal container,
(B) is sectional drawing which follows the bb line | wire of (a).

FIG. 4 is a cross-sectional view of a conventional gas insulated switchgear.

FIG. 5 is a table showing a relationship between an insulating coating and a metal foreign matter floating electric field.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... High voltage conductor, 2 ... Metal container, 3 ... Insulating spacer, 4
... insulating gas, 5: trace of metal foreign matter behavior, 6 ... insulating coating, 7
... Insulation coating agent inlet, θ ... Insulation coating range center angle.

Continuation of front page (72) Inventor Motoharu Shiiki 2-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture F-term in the Toshiba Hamakawasaki Plant (reference) 5G017 BB20 GG02 5G365 DA09 DD04 DP01

Claims (4)

[Claims] 1. A metal container having a cylindrical shape and filled with an insulating gas, and a current-carrying conductor inserted in the metal container and supported by an insulating spacer, wherein the center of the metal container in the circumferential direction on the inner surface is provided. A gas insulated switchgear having an insulating coating formed within an angle of 180 degrees or less. 2. The gas insulated switchgear according to claim 1, wherein the insulating coating portion is disposed on the upper surface during a withstand voltage test and disposed on the lower surface during commercial operation. 3. The gas insulated switchgear according to claim 1, wherein the insulating coating portion is formed after the withstand voltage test is completed. 4. The gas insulated switchgear according to claim 1, wherein the insulating coating portion is formed of an epoxy resin paint or a fluororesin paint.