JPH0246111A - Insulation structure in electrical machinery and apparatus - Google Patents

Abstract

PURPOSE:To shrink the profile of a machine to be contained and to reduce the size thereof by making semi-spherical the end section of a charging rod section projecting outward from an electrical machine to be operated in insulation gas and arranging an L-shaped projecting section at the base section of the semi-spherical face continuously thereto then covering the L-shaped curved section and the semi-spherical face tightly with a U-shaped insulator. CONSTITUTION:A semi-spherical face 4a0 having curvature equal to the radius of a movable contactor 4a is formed at the rear end of the movable contactor 4a made of copper, and a curved section 4c having L-shaped cross-section and provided with a short parallel section at the front end of the movable contactor 4a is formed through a gap of several mm at the base end of the semi-spherical face 4a0. An approximately U-shaped insulation layer 9 is formed through injection of epoxy resin at the outer circumferences of the curved section 4c and the semi-spherical face 4a0, where the insulation layer 9 is made thick around the semi-spherical face 4a0. Since the electrical field at the triple joint in the border of the charged section and the insulated section is relieved and the insulation characteristic is improved, the profile of an electrical machine to be operated in the insulation gas or the container therefor can be shrinked.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an insulation structure for electrical equipment used in gas-insulated closed switchboards and the like.

(Prior Art) In FIG. 5 showing an example of a conventional gas-insulated closed switchboard, a front door 1a is attached to the left side, and the airtight structure has sulfur hexafluoride gas (hereinafter referred to as insulating gas) sealed inside. A high-pressure vacuum circuit breaker 2 is housed in the front of the box 1, and a bar-shaped movable contact 4 is mounted on the ceiling and floor with an operating arm 4b.
A disconnector 4 which is opened and closed by moving a is attached, and the front end of the disconnector 4 is connected to the circuit breaker 2 through a conductor 3. Further, on the rear wall of the box body 1, a bus bar 5 attached to the paddle 7 airtightly penetrates the left and right side panels (not shown) of the box body 1 with insulating bushings (not shown), and from this bus bar 5, conductors 3 are respectively connected. is connected to the rear terminal of the disconnector 4 on the ceiling.

Furthermore, a cable pen 6 is attached to the rear of the floor of the box 1, and is connected by a conductor 3 to a rear terminal of a disconnector 4 attached to the floor.

By the way, in a gas-insulated closed switchboard that houses electrical equipment and connects them with conductors, the ends of live parts are made with a large curvature in order to prevent discharge due to concentration of electric fields. Since this cannot be done with a rod-shaped end such as the rear end of the movable contactor 4a, a large spherical shield ring 8 is attached as shown in FIG. 6 (for example, Japanese Patent Application Laid-open No. 6-128807). This is because the insulating gas exhibits strong electrical negativity, and dielectric breakdown is determined by the maximum electric field strength.

(Problems to be Solved by the Invention) However, this shield ring 8 not only takes time to manufacture, but also physically restricts the arrangement of adjacent devices. For example, in FIG. 5, the operating arm 4b and the conductor 3 connected to the rear terminal of the disconnector 4 must escape through the shield ring 8. Furthermore, if the interphase dimension of the disconnector 4 increases, not only will the external size become larger, but also the increased weight of the shield ring 8 will increase the operating force of the operating arm 4b. As a result, the box body 1 also becomes larger, and the features of the gas-insulated closed switchboard are lost.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to obtain an insulating structure for electrical equipment without increasing the size of the end portion of the equipment used in an insulating gas, and without increasing the external size or installation area of the equipment to which it is applied.

[Structure of the invention]

(Means and Effects for Solving the Problems) According to the present invention, the end of a rod-shaped live part protruding outside from an electrical device used in an insulating gas is made into a hemispherical surface.

By providing an L-shaped protruding curved portion following the hemisphere at the base of the hemispherical surface, and closely covering this curved portion and the hemispherical surface with a U-shaped insulator, the live part and the insulator are closely covered. This is an insulation structure for electrical equipment that improves the insulation properties of the end of a rod-shaped live part of the electrical equipment by relaxing the electric field at the triple junction of the boundary line.

(Example) Hereinafter, an example of the insulating structure for an electrical device of the present invention will be described with reference to FIG.

FIG. 1 shows an example in which the movable contact 4a is applied to the rear end of the disconnector 4 shown in FIG. A surface 4ao is formed, and a curved portion 4C having a short parallel portion in the direction of the front end of the movable contact 4a is formed at the base end of the hemispherical surface 4a with a gap of several meters in the cross-sectional shape.

The curved portion 4C and the outer periphery of the hemispherical surface 4ao are covered with a substantially U-shaped insulating layer 9 covered with epoxy resin casting.
is formed, and this insulating layer 9 has a hemispherical surface 4a.

It is thicker around the area.

Next, the operation of the insulation structure of the electrical equipment used in the insulating gas constructed as described above will be explained.

As mentioned above, dielectric breakdown in an insulating gas is determined by the maximum electric field strength, but in FIG. The joint A of the insulating layer becomes a so-called triple junction, and the electric field strength is maximum. For example, if a metal plate E at ground potential is placed on the right side of the insulating layer 9 as shown in Fig. 1, the joint A becomes the weakest point. becomes. (Note: Of course, the epoxy thickness of the insulating layer 9 on the hemispherical surface 4ao is the required thickness, for example, the rated voltage is 77KV, the withstand voltage is 400KV (lightning impulse voltage), and the thickness t = 4
Approximately 00KV/40KV/nn=1o+m+ is required. ) This is because the dielectric constant (3 to 6) of the insulating layer 9 is larger than the dielectric constant 1 of the insulating gas, and the voltage between the metal plates 8 is SF
This is because the shared voltage per unit distance in the G gas decreases, and the electric field strength on the right end surface of the insulating layer 9 decreases. Therefore, the type of dielectric breakdown is a flashover from the right end from the joint A through the surface of the insulating layer 9.

However, in the insulation structure of the electrical equipment of the present invention, the curved portion 4c is further provided on the right side of the joint A, so that the electric field strength of the weakest joint A is reduced, and the withstand voltage characteristics with the metal plate E are increased. Can be done. therefore.

This is an electrical appliance that can reduce the installation area by taking advantage of the features of gas-insulated closed switchboards that aim to reduce the size and size of electrical equipment used in insulating gas without increasing the size of the ends of electrical equipment used in the past. It is possible to obtain an insulating structure for equipment.

FIG. 2 shows another embodiment of the insulating structure for electrical equipment according to the present invention.

In FIG. 2, the left end of the insulating layer 9 is flush with the inner surface of the curved portion 4c, forming a gap 4d inside.

In this case, the triple point junction is located inside and the electric field is further weakened, so there is an advantage that the withstand voltage characteristics are further improved.

Although there is a concave portion between the hemispherical surface 4ao and the curved portion 40 in FIGS. 1 and 2, it may be a straight line or a convex surface with a large curvature as shown in FIG.

Furthermore, when the current carrying capacity of the disconnector 4 is large and the voltage is low,
As shown in FIG. 4, the diameter may be reduced only at the right end.

In addition, in FIGS. 1 and 2, when there is a risk that the boundary between the hemispherical surface 4ao and the insulating layer 9 will peel off due to expansion or contraction of the movable contact 4a due to operation or stoppage of equipment, for example, the boundary surface A stress relieving layer such as a silicone resin adhesive may be provided.

In addition, for the movable contact 4a, only the current-carrying part on the left side may be made of a copper rod, and the part to which the insulating layer 9 is applied may be made separately (note: the material may also be iron or An), and it may be screwed together with the left side. (See Figure 4).

In this case, there is an advantage that the movable contactor 4a can be manufactured more easily.

Furthermore, in FIG. 4, the portion to which the insulating layer is to be applied may be provided with a filler metal having a threaded portion made of conductive resin, and an insulating layer 9 may be provided around the outer periphery. In this case, there is an advantage that the right side of the threaded part is lighter.

〔Effect of the invention〕

As described above, according to the insulation structure of the electrical equipment of the present invention.

The end of a rod-shaped live part provided in an insulating gas is made into a hemispherical surface, a curved part continuing to the hemispherical surface is provided at the base of this hemispherical surface, and this curved part and the hemispherical surface are covered with an insulating material in a substantially U-shape. By reducing the electric field at the triple junction at the boundary between the live part and the insulating part and improving the insulation properties, we have created an insulation structure for electrical equipment that can reduce the external size of electrical equipment and storage devices used in insulating gas. can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional view showing one embodiment of the insulating structure for electrical equipment of the present invention, and FIGS. 2, 3, and 4 are half-sectional views showing other embodiments of the insulating structure for electrical equipment of the present invention. A sectional view, FIG. 5 is a side view showing an example of application of the insulation structure of a conventional electric device, and FIG. 6 is an enlarged view of the main part of FIG. 4a... Movable contact 'Iao... Hemispherical surface 4c - Curved portion 9... Insulating layer agent Patent attorney Noriyuki Chika Ken Ken Daishimaru Figure 2 Figure 3 Figure 5 Figure 6 Figure 4 figure

Claims (1)

[Claims] In an electrical device housed in a box filled with insulating gas and having a rod-shaped live part with a hemispherical end protruding outside, the end of the rod-like live part has an outer surface continuous with the hemispherical surface. An L-shaped curved part protruding from the rod-shaped live part is provided, and a U-shaped insulating layer is provided on the outside of the curved part and the hemispherical surface, and on the outer surface of the hemispherical surface and the curved part. Insulation structure of electrical equipment.