CN201898025U - Current transformator and shielding case - Google Patents

Abstract

The utility model relates to a current transformer and a shielding cover. The current transformer is assembled from a device body and a base assembly. The device body is composed of a primary cylinder body, a grounding pipe, a shielding cylinder, a shielding It is fixed on the shielding cover, and then fixed on the bottom of the primary cylinder through the pot insulator. The center of the shielding cover body is provided with a jack for the grounding pipe to pass through, and the two ends are provided with inner hooks. The inner hook edge of the shielding cover The outer peripheral surface of the shield is arc-shaped; the utility model optimizes the inner hook structure of the shield without increasing the outer dimension of the shield, adopts a multi-curvature radius arc structure, and effectively increases the radius of curvature of the electrode edge. The optimization of the electric field inside the pot insulator and the distribution of the electric field along the surface is realized, the electric field intensity on the surface of the shielding cover is effectively suppressed, and the insulation level of the ultra-high voltage current transformer is greatly improved.

Description

A current transformer and shielding case

technical field

The utility model belongs to the field of high-voltage transformation equipment in electric power systems, and in particular relates to a shielding cover and a current transformer for an ultra-high-voltage current transformer.

Background technique

In the current transformer, the secondary coil of the current transformer is fixed in the shielding cylinder (low potential), the shielding cylinder passes through the shielding cover, and is fixed on the flange of the cylinder by the pot insulator (high potential); the pot insulator is used as The key component connecting the high potential cylinder and the ground potential shield cylinder plays a dual role of electrical insulation and mechanical support; and the shield is very important for the electric field in the current transformer, especially the reasonable distribution of the electric field inside the pot insulator and along the surface , the main performance is: (1) Make the electric field distribution of the basin insulator uniform, reduce its electric field intensity along the surface; (2) Shield the insert of the basin insulator, reduce the electric field intensity at the end of the insert; (3) Reduce the surface of the shielding cover Electric field strength. With the increase of the voltage level of the current transformer, the internal electric field deteriorates sharply, and the structure of the original shield can no longer meet the insulation requirements of the ultra-high voltage current transformer; in order to make the electric field distribution of the pot insulator as uniform as possible, reduce the electric field intensity along the surface , and at the same time shield the insert of the pot insulator to reduce the electric field intensity at the end of the insert, and it is particularly necessary to design a shielding cover for an ultra-high voltage current transformer with a reasonable electrode shape.

The current transformer shown in Figure 1, the current transformer is assembled by the body and base components, the body is composed of a primary cylinder, grounding pipe, shielding cylinder, shielding cover and pot insulator, the shielding cylinder is fixed on the shielding Cover, and then fixed to the bottom of the primary cylinder through basin insulators. As shown in Fig. 2, the shielding cover is provided with a jack in the center for the insertion of the grounding pipe.

Utility model content

The purpose of the utility model is to provide a current transformer and a shielding cover to solve the problem that the existing shielding cover cannot meet the insulation requirements of the ultra-high voltage current transformer.

In order to achieve the above purpose, a shielding cover of the present invention has an insertion hole in the center of the shielding cover body, and inner hook edges at both ends, and the outer peripheral surface of the inner hook edge is an arc-shaped surface.

Further, the outer peripheral surface of the inner hook rim is formed by smoothly connecting at least two sections of arc-shaped surfaces from the root to the tip of the inner hook rim.

Further, the radius of curvature of the outer peripheral surface of the inner hook rim increases sequentially from the root to the tip of the inner hook rim.

A current transformer of the utility model is assembled from a body and a base assembly. The body is composed of a primary cylinder, a grounding pipe, a shielding cylinder, a shielding cover and a pot insulator, and the shielding tube is fixed on the shielding cover. Then it is fixed on the bottom of the primary cylinder through basin insulators. The center of the shielding cover body is provided with a jack for the insertion of the grounding pipe, and the two ends are provided with inner hook edges. The outer peripheral surface of the inner hook edge of the shielding cover is an arc. shape.

Further, the outer peripheral surface of the inner hook rim of the shielding cover is formed by smoothly connecting at least two sections of arc-shaped surfaces from the root to the tip of the inner hook rim.

Further, the radius of curvature of the outer peripheral surface of the inner hook edge of the shield expands sequentially from the root of the inner hook edge to the tip of the arc surface.

A current transformer and shielding cover of the utility model optimizes the structure of the inner hook edge of the shielding cover without increasing the outer dimension of the shielding cover. The outer peripheral surface of the inner hook edge is an arc surface, and the outer peripheral surface of the inner hook edge From the root to the tip of the inner hook, it is formed by at least two sections of arc-shaped surfaces smoothly connected, and the radius of curvature of the arc-shaped surfaces increases sequentially. In this way, the arc-shaped structure with multiple curvature radii is adopted to effectively increase the radius of curvature of the edge of the electrode and realize the basin The optimization of the electric field inside the type insulator and the distribution of the electric field along the surface can effectively suppress the electric field intensity on the surface of the shielding cover, and greatly improve the insulation level of the ultra-high voltage current transformer.

Description of drawings

Fig. 1 is the structural schematic diagram of existing current transformer;

Fig. 2 is the structural schematic diagram of existing shielding case;

Fig. 3 is a structural schematic diagram of the utility model shielding cover;

Fig. 4 is a schematic diagram of the assembly structure of the shielding cover in the current transformer of the present invention.

Detailed ways

The shielding cover of the present utility model is shown in Figure 3. The center of the shielding cover body is provided with a socket, and the two ends of the shielding cover are provided with inner hook edges. The surface, that is, the arc surface is formed by smoothly connecting at least two sections of arc surfaces from the inner hook along the root to the tip, and the radius of curvature of the arc surfaces increases sequentially.

The partial assembly structure of the current transformer of the present utility model is shown in Figure 4. The current transformer is assembled from a body and a base assembly. The shielding cylinder 1 is fixed on the shielding cover 2, and then fixed on the bottom of the primary cylinder 1 with the insert 5 through the basin insulator 3. The center of the shielding cover body is provided with a jack for the grounding pipe to pass through. , both ends of the shielding cover are provided with an inner hook edge, the outer peripheral surface of the inner hook edge is an arc surface, and the outer peripheral surface of the inner hook edge is an arc surface from the root of the inner hook edge to the tip by at least two arc-shaped surfaces smoothly connected , and the radius of curvature of the arc surface increases sequentially.

The utility model does not need to increase the size of the shielding cover, only by optimizing the shape of the inner hook to reduce the surface field strength of the pot insulator, shield the pot insulator insert and reduce the surface field strength of the shielding cover; it does not need to increase materials and processing The cost can meet the insulation requirements of ultra-high voltage current transformers; after the utility model is applied, the insulation level of 500kV current transformers is increased from 680/1175/1550/1675kV to 740/1300/1675/1926kV respectively.

Claims (5)

1. A shielding cover, the center of the shielding cover body is provided with a socket, and the two ends are provided with inner hook edges, characterized in that: the outer peripheral surface of the inner hook edge is an arc-shaped surface. 2 . The shielding cover according to claim 1 , wherein the outer peripheral surface of the inner hook rim is smoothly connected by at least two sections of arc-shaped surfaces from the root to the tip of the inner hook rim. 3 . 3 . The shielding cover according to claim 2 , wherein the radius of curvature of the outer peripheral surface of the inner hook edge increases sequentially from the root to the tip of the inner hook edge. 4 . 4. A current transformer, which is assembled from a body and a base assembly, the body is composed of a primary cylinder, a grounding pipe, a shielding cylinder, a shielding cover and a pot insulator, the shielding tube is fixed on the shielding cover, and then It is fixed on the bottom of the primary cylinder through a basin-type insulator. The center of the shield body is provided with a jack for the grounding pipe to pass through, and the two ends are provided with inner hook edges. The feature is: the outer circumference of the inner hook edge of the shield The surface is curved. 5. The current transformer according to claim 4, characterized in that: the outer peripheral surface of the inner hook edge of the shielding cover is smoothly connected by at least two arc-shaped surfaces from the root of the inner hook edge to the tip 6 . The current transformer according to claim 5 , wherein the radius of curvature of the outer peripheral surface of the inner hook edge of the shielding cover increases sequentially from the root of the inner hook edge to the tip of the arc surface.

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