CN217009046U - Multisection porcelain shell type vacuum arc-extinguishing chamber with external shielding structure - Google Patents

Abstract

The utility model discloses a multi-section porcelain shell type vacuum arc-extinguishing chamber with an external shielding structure, which comprises a vacuum arc-extinguishing chamber body (1) and a shielding structure (2); the vacuum arc extinguish chamber body (1) is provided with a plurality of sections of porcelain shells, an inner shielding cover is arranged between two adjacent sections of porcelain shells, and a shielding structure (2) protruding towards the outside of the porcelain shell is arranged on the circumference of the root part of each inner shielding cover. According to the utility model, under the condition that the diameter of the vacuum arc extinguish chamber is not obviously increased, the shielding structure is additionally arranged at the position of welding the inner shielding cover between the ceramic shell and the ceramic shell, so that the effect of balancing the external electric field of the vacuum arc extinguish chamber with a multi-section ceramic shell structure of multiple inner shielding covers is achieved, and the problem of electric field concentration on a three-phase junction point is reduced.

Description

A multi-section porcelain shell type vacuum interrupter with external shielding structure

technical field

The utility model belongs to the field of medium and high voltage vacuum switches, in particular to a multi-section ceramic shell type vacuum interrupter with an outer shielding structure.

Background technique

SF ₆ gas is widely used in power systems due to its excellent insulation and arc extinguishing properties, but at the same time, as a highly stable and strong greenhouse effect gas (its GWP value is 23,500, and its atmospheric life is 3,200 years), it provides long-term benefits to human beings. serious impact on the living environment. It is imperative to limit or reduce the use and emission of SF ₆ gas in power system equipment. The vacuum interrupter has the characteristics of high insulation performance and environmental friendliness, and has been widely used in the medium voltage field (12 ~ 40.5kV), and is regarded as one of the important choices to replace the SF6 gas switch in the field of high voltage power transmission.

Under normal circumstances, the vacuum interrupter needs to be placed in a closed gas chamber filled with a certain pressure gas when it is used. At present, the application range of vacuum interrupter is constantly developing towards high voltage level and miniaturization, which requires the vacuum interrupter to have higher insulation parameters and better insulation performance. High voltage and miniaturization (if there is no requirement for high voltage, the vacuum interrupter is usually a ceramic shell or glass shell, and there is no such structural state of multi-stage inner shielding; if there is no requirement for miniaturization, then The multi-stage inner shield can be placed inside the porcelain shell, and there is no situation that the inner shield root will divide the porcelain shell, so the requirements for high voltage and miniaturization are proposed here.) The vacuum interrupter is usually equipped with a multi-section porcelain shell. An inner shield is welded between the porcelain shells to equalize the electric field inside the vacuum interrupter. Experimental studies have shown that the same multi-section porcelain shell vacuum interrupter is placed in a metal shell filled with insulating gas, compared with placing it in the atmosphere or in an insulating material shell such as a porcelain filled with insulating gas, the arc extinguishing chamber electrode If the same power frequency or lightning impulse voltage is applied between, the breakdown outside the porcelain shell and inside the porcelain shell is more likely to occur. The reason of electric field deterioration is analyzed by simulation calculation and optimization method is proposed. The outside of the vacuum interrupter in the metal shell is usually a gas insulating medium, and the electric field at the three-phase junction of gas, metal and ceramics is not well distributed. The groove structure leads to the existence of the wedge-shaped air gap, which will aggravate the electric field accumulation in the groove part, and in severe cases, the insulation of the vacuum interrupter will be damaged and the switch will fail. With the development of the vacuum interrupter to high-voltage applications and miniaturization, the vacuum interrupter is required not only to have good internal insulation performance, but also to have better external insulation performance.

A shielding structure protruding to the outside is added between the multiple inner shields and the multi-section ceramic shells of the vacuum interrupter with a multi-section ceramic structure to balance the electric field distribution at the three-phase interface of metal, ceramic and gas, and improve the vacuum interrupter. Overall insulating properties.

At present, the application range of vacuum interrupters is constantly developing towards high voltage level and miniaturization, which requires vacuum interrupters to have higher insulation parameters and better insulation performance. The high-voltage vacuum interrupter is usually equipped with multi-section ceramic shells, and an inner shield is welded between the ceramic shells to balance the electric field inside the vacuum interrupter. The insulation performance of the vacuum interrupter is usually good. However, the outside of the vacuum interrupter is usually air or other insulating medium, and the electric field at the three-phase junction of air (or other insulating medium), metal and ceramics is not well distributed. The groove structure formed after welding between them leads to the existence of a wedge-shaped air gap, which will aggravate the electric field accumulation in the groove part, and in severe cases, will lead to the destruction of the insulation outside the vacuum interrupter and the failure of the switch. With the development of the vacuum interrupter to high-voltage applications and miniaturization, the vacuum interrupter is required not only to have good internal insulation performance, but also to have better external insulation performance.

Utility model content

The purpose of the utility model is to provide a multi-section porcelain shell type vacuum interrupter with an outer shielding structure in view of the problem of insufficient insulation performance of the existing vacuum interrupter.

The utility model adopts the following technical solutions to realize:

A multi-section porcelain shell type vacuum interrupter with an outer shielding structure, comprising a vacuum interrupter body and an outer shielding structure;

Inside the vacuum interrupter body is an inner shield with a rotational axis symmetrical structure. The root of the inner shield divides the rotational axis symmetrical structure of the porcelain shell into three or more parts that are not in contact with each other, and along the root of the inner shield is away from the center. The axis O, and the outer shielding structure protruding in the circumferential direction, the root of the outer shielding structure is fixedly connected with the root of the inner shield.

A further improvement of the present invention is that the outer shielding structure is made of metal material or insulating material.

A further improvement of the present invention is that when the outer shielding structure is made of metal material, the outer shielding structure and the inner shielding structure are integral structures before being welded with the porcelain shell.

A further improvement of the present invention is that the root of the outer shielding structure can completely fill the gap formed by the adjacent multi-section ceramic shells and the inner shielding case, and the end of the outer shielding structure is higher than the outer surface of the ceramic shell.

A further improvement of the utility model is that the end of the outer shielding structure higher than the surface of the porcelain shell extends along the direction of the central axis O and covers the surface of the porcelain shell, and the outer shielding structure is discontinuous between the outer surfaces of the porcelain shell.

A further improvement of the present invention lies in that the end of the outer shielding structure which is higher than the surface of the porcelain shell extends along the direction of the central axis O and does not cover the surface of the porcelain shell.

A further improvement of the present invention is that the distance between the part of the end of the outer shielding structure extending along the direction of the central axis O and the outer surface of the porcelain shell is ≥1 mm.

A further improvement of the present invention is that the surface of the outer shielding structure is smooth and at least one corner is rounded.

The utility model at least has the following beneficial technical effects:

The utility model provides a multi-section ceramic shell type vacuum interrupter with an outer shielding structure. Under the circumstance that the diameter of the vacuum interrupter is not significantly increased, the inner shield is welded between the ceramic shell and the ceramic shell. The shielding structure is installed to balance the external electric field of the vacuum interrupter with multiple inner shields and multi-section ceramic shell structures, so as to reduce the electric field concentration problem at the three-phase junction point, and then optimize the multiple inner shields and multi-section ceramic shell structure. Excellent external insulation performance of the vacuum interrupter, prolonging the service life of the vacuum interrupter.

Therefore, the utility model has a simple structure and can achieve the expected technical effect.

Description of drawings

FIG. 1 is a schematic structural diagram of a multi-section porcelain shell type vacuum interrupter with an outer shielding structure according to the present invention.

FIG. 2 is a schematic structural diagram of the first shielding structure of the present invention.

FIG. 3 is a schematic structural diagram of a second shielding structure of the present invention.

FIG. 4 is a schematic structural diagram of a third shielding structure of the present invention.

FIG. 5 is a schematic diagram of a wedge-shaped air gap in a vacuum interrupter with a conventional outer shield structure.

Description of reference numbers:

1. Vacuum interrupter body, 1.1, Static end cover, 1.2, Porcelain shell, 1.2.1~1.2.4, Section 1 to Section 4 porcelain shell, 1.10, Along the root of the inner shield, 1.3 .1 ~ 1.3.3, the root of the first inner shield to the root of the third inner shield, 1.4, the movable end cover plate, 1.5, the movable conductive rod;

2. External shielding structure, 2.10. The root of the external shielding structure.

Detailed ways

The present utility model will be further described below in conjunction with the accompanying drawings.

The utility model conducts an insulation test on the circuit breaker formed by the vacuum interrupter arranged in the metal shell. After the test, it is found that there is surface discharge on the surface of the ceramic shell of the vacuum interrupter. The simulation found that there is a large electric field concentration between the porcelain shells and the exposed root of the inner shield. Therefore, due to the needs of the project, the design of adding external shielding was carried out for the vacuum interrupter. Then, the design effect was simulated, and it was found that the maximum value of the electric field decreased from 25kV/mm to about 9kV/mm, indicating that the optimized design had an obvious effect of uniform electric field strength.

As shown in Figure 1, the utility model provides a multi-section ceramic shell type vacuum interrupter with an external shielding structure, including a vacuum interrupter body 1 and a shielding structure 2; the vacuum interrupter body 1 has a multi-section ceramic shell The inner shielding cover is arranged between two adjacent porcelain shells, and the circumferential direction of the root of each inner shielding cover is provided with a shielding structure 2 protruding to the outside of the porcelain shell. The vacuum interrupter body 1 is provided with an inner shielding cover 1.3 with a rotational axis symmetrical structure. The root 1.10 of the inner shielding cover divides the ceramic shell 1.2 with a rotational axis symmetrical structure into three or more parts that are not in contact with each other. The root 1.10 of the outer shielding structure 2 protrudes away from the central axis O and in the circumferential direction, the root 2.10 of the outer shielding structure is fixedly connected with the root 1.10 of the inner shield.

One end of the multi-section porcelain shell of the vacuum interrupter body 1 is provided with a static end cover 1.1, the other end is provided with a movable end cover 1.4, and a movable conductive rod 1.5 is connected to the center of the movable end cover 1.4. The multi-section porcelain shell in the utility model comprises a first section of porcelain shell 1.2.1 to a fourth section of porcelain shell 1.2.4, correspondingly having a first inner shielding cover root 1.3.1 to a third inner shielding cover root 1.3.3.

Before the vacuum interrupter enters the vacuum furnace for welding, the outer shield and the inner shield installed between the porcelain shells can be welded together first, and then welded in the vacuum furnace as a whole. The outer shield can be made of metal. Its structural form can be as shown in but not limited to Figure 2

The utility model refers to the joint between the outer shield and the inner shield as the root of the outer shield. A part of the outer contour of the outer shield is arc-shaped, including one or more arcs and straight segments with different radii. The arc farther away from the porcelain shell or glass shell has the largest radius, and the outer shield head is not lower than the outer surface of the porcelain shell. . If it is a metal outer shield, the distance between the outer shield head and the surface of the ceramic shell should be ≥ 1mm, otherwise a new small air gap will be formed, causing the electric field to concentrate again.

As shown in Figure 3, after the vacuum interrupter is welded to form a finished product, insulating material can be filled at the welding place between the porcelain shell and the porcelain shell to cover the existing sharp corners and the wedge-shaped air gap, so as to play the role of To balance the effect of the electric field, the insulating material may be, but not limited to, insulating colloid.

The root of the outer shield needs to completely fill the gap formed between the porcelain shells, the section of the outer shield head is partially arc-shaped, and the outer shield head is not lower than the outer surface of the porcelain shell. If it is an insulating shielding structure, the shielding head needs to cover the edge formed by the outer surface and the bottom surface of the porcelain shell.

As shown in Figure 4, after the vacuum interrupter welding is completed to form a finished product, a suitable spring can be selected at the welding place between the porcelain shell and the porcelain shell to be embedded in the groove formed at the welding place, and the groove is filled with The conductive colloid is used to bond the selected spring and the vacuum interrupter together, and the exposed part of the spring must not be lower than the surface of the porcelain shell, so as to balance the electric field.

Different forms of outer shielding can be applied individually or in combination, depending on the processing cost and effect requirements.

In addition, the wedge-shaped air gap will be explained again. Microscopically, the groove formed by the welding of the porcelain shell-inner shielding cover-porcelain shell is shown in Figure 5, and the one shown at A is a wedge-shaped air gap. The small wedge-shaped air gap is filled and eliminated, which is beneficial to equalize the electric field, so as to achieve the desired implementation effect.

To sum up, the key innovation of the concept of the present utility model is: the utility model does not significantly increase the diameter of the vacuum interrupter, by adding insulation or metal material at the position of the inner shielding cover welded between the porcelain shells. The shielding structure is used to balance the external electric field of the vacuum interrupter with multiple inner shields and multi-section ceramic shell structures, thereby reducing the electric field concentration problem at the three-phase junction point, and then optimizing the multiple inner shields and multi-section ceramic shell structures. The external insulation performance of the vacuum interrupter extends the service life of the vacuum interrupter.

Claims (8)

1. A multi-section porcelain shell type vacuum interrupter with an outer shielding structure is characterized in that, comprising a vacuum interrupter body (1) and an outer shielding structure (2); The vacuum interrupter body (1) is provided with an inner shielding cover (1.3) with a rotational axis-symmetric structure, and the root (1.10) of the inner shielding cover divides the rotational axis-symmetrical ceramic shell (1.2) into three sections and above without contacting each other The part of the outer shielding structure (2) which is away from the central axis O along the root (1.10) of the inner shield and protrudes in the circumferential direction, the root (2.10) of the outer shielding structure is fixed with the root (1.10) of the inner shield connect. 2 . The multi-section ceramic shell type vacuum interrupter with an outer shielding structure according to claim 1 , wherein the outer shielding structure ( 2 ) is made of metal material or insulating material. 3 . 3 . The multi-section porcelain shell type vacuum interrupter with an outer shielding structure according to claim 2 , wherein when the outer shielding structure (2) is made of metal, the outer shielding structure (2) and the The inner shield (1.3) is an integral structure before being welded with the porcelain shell. 4. A multi-section ceramic shell type vacuum interrupter with an outer shielding structure according to claim 1, characterized in that the root (2.10) of the outer shielding structure can completely fill the adjacent multi-section ceramic shells (1.2) The gap formed with the inner shielding cover (1.3), and the end of the outer shielding structure (2) is higher than the outer surface of the porcelain shell. 5. A multi-section porcelain shell type vacuum interrupter with an outer shielding structure according to claim 1, wherein the end of the outer shielding structure (2) higher than the surface of the porcelain shell extends along the direction of the central axis O , covering the surface of the porcelain shell, and the outer shielding structure (2) is discontinuous between the outer surfaces of the porcelain shell. 6. A multi-section porcelain shell type vacuum interrupter with an outer shielding structure according to claim 1, wherein the end of the outer shielding structure (2) higher than the surface of the porcelain shell extends along the direction of the central axis O , not covering the surface of the porcelain shell. 7. A multi-section porcelain shell type vacuum interrupter with an outer shielding structure according to claim 6, characterized in that the part of the end of the outer shielding structure (2) extending along the direction of the central axis O and the porcelain shell The distance between the outer surfaces is ≥1mm. 8 . The multi-section porcelain shell type vacuum interrupter with an outer shielding structure according to claim 1 , wherein the outer shielding structure ( 2 ) has a smooth surface and at least one corner is rounded. 9 .

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