JPS5883514A - Gas insulated electric device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This invention relates to gas insulated electrical equipment.

The present invention relates to a gas insulated electrical device having a structure in which impurities in a closed tank or container in which the insulating gas is sealed do not adversely affect the withstand voltage.

When a gas-insulated electric device is in operation, if impurities enter or are generated in the container for some reason, the levitation blade f/ acts on such impurities due to electrostatic force depending on the electric field strength, and the levitation blade f/ When the blade f/ exceeds the gravity f1 of the impurity and the adhesive force f with the container, the impurity floats to the surface. The floating impurities are determined by the distribution of electric field strength within the container, the shape of the impurities, and the weight of the impurities.

It moves extremely complicatedly and irregularly depending on the condition of the surface of the container. This impurity causes negative effects such as internal circuits. Therefore, it has been conventionally considered to apply K to prevent the migration of impurities.

Figures 1 and 2 are diagrams showing an example of a conventional gas insulated electric device (percentage switch type), and show a gas insulated bus bar as the gas insulated electric device. A dielectric film is formed on the inner surface of the sealed tank, that is, the container l.
It is insulated by an insulating gas J sealed in the container, and the conductor is supported by an insulating spacer (not shown) over the center of the container.

In a gas insulated electrical device having such a structure, when impurities enter or occur in the container, movement of the impurities is suppressed in a first-order manner. In other words, the dielectric film is polarized as a voltage is applied, and a polarized charge appears on the surface (conductor side) of the dielectric film. The impurity causes polarization on the surface of the dielectric film, and an attractive force f acts between the impurity and the dielectric film,
The sum of the downward forces of gravity fJ, adhesive force f, and suction force f exceeds the floating blade f due to electrostatic force.

Therefore, irregular movement of impurities is suppressed.

By the way, with this method, as shown in Figure 3, 5K,
For example, when an elongated impurity 3 made of metal enters or occurs, if 10,000-s''/sf +f, +f, the impurity rises from the state shown in Figure 3 to the state shown in Figure 3, and the impurity 3 As the electric field at the tip j51 becomes stronger, the floating blade f due to electrostatic force becomes larger and may rise and move slightly as shown in Fig. 5. If this continues, it will have a negative effect on the insulation. There was a drawback.

This invention was made in view of the above.

The aim is to eliminate the above-mentioned drawbacks and provide a gas-insulated electrical device with good insulation performance, and the feature is that a dielectric film is formed on the ground side of the inner surface of the container, that is, the sealed tank, where the electric field is strong. The company provides gas insulated electrical equipment that

The invention will now be described with reference to one illustrated embodiment.

As shown in Figures 6 to 6, a dielectric film as described above is not formed in the area of a relatively uniform electric field within the container l.
Apply dielectric film only to areas with particularly strong electric fields on the inside of the container.
It forms 〇.

For example, in FIG. 1, a seventh
In FIGS. and t, a dielectric film 0 is formed on the surfaces of the shield ring t for alleviating the electric field of the insulating support cylinder and the shield ring for alleviating the electric field inside the above-mentioned 7 lunges B.

If impurity 5 enters such a gas-insulated electrical device, K, impurity! moves around inside the container by moving irregularly according to the above-mentioned principle, but eventually the floating blade f becomes smaller where the electric field is weak.

Shield ring t for mitigating electric field in recessed part of flange part 1
is trapped at the weak electric field 9' on the inner surface of the container I. By the way, if the dielectric film -〇 is not formed on the inside of the 7 flange 6 or on the shield link t, impurity j
Since the floating blade f acting on K is not weakened, the impurity j that once moved to a location where the electric field is strong will no longer fall to the location t' where the electric field is weak on the inside surface of the container of the shield or the recess, and at this location, impurity If the movement continues, it will become K. If such a dielectric film 〇 is formed only in the areas K where the electric field is strong, the impurity 1 will smoothly fill the concave areas and areas t' where the electric field is weak.
can be reliably caught. Also, ・Container l
The cited method of forming a dielectric film on most of the inner surface of the
It itself is electrically charged and easily attracts impurities during manufacturing and installation, but in this invention, the film is formed in a very limited area, so in the unlikely event that impurities are attracted during manufacturing or installation! Even if it is charged and attracted, it is relatively easy to remove it. still.

In actual application, before applying the grid voltage.

Preliminary voltage is applied in stages using a test transformer or the like, so that the impurity 3 is trapped in areas where the electric field is weak.

[Brief explanation of drawings]

1st and co! 1 shows a part of a conventional gas-insulated electric device, and FIG. 1 is a vertical sectional view, and FIG.
Cross-sectional view at K, No. ? Figure -j is a vertical cross-sectional view showing the impurity movement mode, Figure 6 is a vertical cross-sectional view showing an embodiment of the present invention, Figure 7 is a vertical cross-sectional view of another actual failure example, and Figure 7 is a vertical cross-sectional view showing an embodiment of the present invention. FIG. /-... sealed tank or container, co... dielectric film,
J...Insulating gas, Da...Conductor! ...Impurities, 4.
・Flange part, 7.. Insulating support cylinder, t.. Shield ring, ri.. Recessed part, t'.. Place where the electric field is weak on the inner surface of the container, -〇.. Dielectric film. Agent Shin Kuzuno −

Claims (1)

[Claims] In a gas-insulated electrical device equipped with a sealed tank filled with a high-performance insulating gas, 7 on the inner surface of the sealed tank
A gas-insulated electrical device characterized in that a dielectric film is formed in areas where the electric field is strong on the ground side, such as the flange attachment part or the convex part of the shield.