Ceramic insulator for vacuum interrupters

Abstract

A ceramic insulator for vacuum interrupters extends along a longitudinal extent and forms a cavity in said longitudinal extent. The cavity has a first opening on a first end of the longitudinal extent and a second opening on a second end of the longitudinal extent. The openings are designed so that they can be sealed in a gas-tight manner using appropriate connections. The sealed first opening is designed to guide at least one fixed contact into the cavity, and the sealed second opening is designed to guide at least one moving contact into the cavity. The ceramic insulator has, on an inner face of the cavity, one or multiple electrically conductive discharge path interrupters extending perpendicularly to the longitudinal extent of the ceramic insulator.

Claims

1. A ceramic insulator for vacuum interrupters, the ceramic insulator comprising: a base body extending along a longitudinal extent and forming a cavity in the longitudinal extent; said cavity having a first opening on a first side of the longitudinal extent, and a second opening on a second side of the longitudinal extent; connectors sealing said first and second openings in a gas-tight manner to form a sealed first opening and a sealed second opening; said first sealed opening being configured for guiding at least one fixed contact into said cavity, and said sealed second opening being configured for guiding at least one moving contact into said cavity; and one or more electrically conductive discharge path interrupters disposed on an inner face of said cavity, said one or more electrically conductive discharge path interrupters extending perpendicularly to the longitudinal extent of said base body, said one or more electrically conductive discharge path interrupters having an annular and/or convex structure, said one or more electrically conductive discharge path interrupters being a plurality of electrically conductive discharge path interrupters disposed with a clearance of between 5 mm and 50 mm therebetween.

2. The ceramic insulator according to claim 1, wherein a ceramic of said base body is a one-piece component.

3. The ceramic insulator according to claim 1, wherein said one or more electrically conductive discharge path interrupters are formed from at least one material selected from the group consisting of a metal, a cermet and a semiconductor.

4. The ceramic insulator according to claim 1, wherein said base body has a cylindrical shape.

5. The ceramic insulator according to claim 1, wherein said one or more electrically conductive discharge path interrupters have characteristics of having been formed by a method selected from the group consisting of a metal-plating method, a spraying method, a chemical deposition method, a printing method, a sputtering deposition method and a vapor deposition method.

6. The ceramic insulator according to claim 5, wherein said one or more electrically conductive discharge path interrupters are additionally provided with a further metal plating.

7. The ceramic insulator according to claim 6, wherein said further metal plating is a metal plating generated by a method selected from the group consisting of a galvanic methods, a chemical deposition method, a printing method, sputtering and vapor deposition.

8. The ceramic insulator according to claim 1, which comprises one or more metal platings arranged in said cavity of said base body, said one or more metal platings extending perpendicularly to the longitudinal extent of said base body and having said one or more electrically conductive discharge path interrupters formed or secured thereon.

9. The ceramic insulator according to claim 1, wherein said clearance is between 10 mm and 20 mm.

10. The ceramic insulator according to claim 1, wherein said base body has an exterior carrying one or more electrically conductive discharge path interrupters, extending perpendicularly to the longitudinal extent of said base body.

11. A vacuum interrupter, comprising the ceramic insulator according to claim 1.

12. A ceramic insulator for vacuum interrupters, the ceramic insulator comprising: a base body extending along a longitudinal extent and forming a cavity in the longitudinal extent; said cavity having a first opening on a first side of the longitudinal extent, and a second opening on a second side of the longitudinal extent; connectors sealing said first and second openings in a gas-tight manner to form a sealed first opening and a sealed second opening; said first sealed opening being configured for guiding at least one fixed contact into said cavity, and said sealed second opening being configured for guiding at least one moving contact into said cavity; and one or more electrically conductive discharge path interrupters disposed on an inner face of said cavity, said one or more electrically conductive discharge path interrupters extending perpendicularly to the longitudinal extent of said base body, said one or more electrically conductive discharge path interrupters having an annular and/or convex structure, said one or more electrically conductive discharge path interrupters being a plurality of electrically conductive discharge path interrupters disposed with a mutual clearance, and an extent of said electrically conductive discharge path interrupters, in a direction of the longitudinal extent, being 5% to 30% of the clearance between said discharge path interrupters in the direction of the longitudinal extent.

13. The ceramic insulator according to claim 12, wherein the extent of said electrically conductive discharge path interrupters is 10% to 20% of the mutual clearance between said discharge path interrupters.

14. A method of producing a ceramic insulator for a vacuum interrupter, the ceramic insulator having a base body extending along a longitudinal extent and forming a cavity in the longitudinal extent; the cavity being formed with a first opening on a first side of the longitudinal extent and with a second opening on a second side of the longitudinal extent; the first and second openings being sealed in a gas-tight manner by appropriate connecting devices, and wherein the sealed first opening is configured for guiding at least one fixed contact into the cavity, and the sealed second opening is configured for guiding at least one moving contact into the cavity; the method comprising: forming on an inner side of the cavity of the ceramic insulator, one or more electrically conductive structures, extending perpendicularly to the longitudinal extent of the ceramic insulator, the one or more electrically conductive structures having an annular and/or convex structure, the electrically conductive structures being formed by a method selected from the group consisting of sputtering, vapor deposition, spraying, chemical deposition and printing; and thereby forming the electrically conductive structures to either function directly as electrically conductive discharge path interrupters, or to support the electrically conductive discharge path interrupters applied to the structures, the electrically conductive discharge path interrupters disposed with a clearance of between 5 mm and 50 mm therebetween.

15. The method according to claim 14, which comprises forming the electrically conductive discharge path interrupters by one or more methods selected from the group consisting of galvanic methods, sputtering, vapor deposition, spraying methods, chemical deposition methods and printing methods applied to the structures.

16. The method according to claim 14, which comprises forming the electrically conductive discharge path interrupters by securing metallic elements as electrically conductive discharge path interrupters to the structures by soldering.

17. The method according to claim 14, which comprises securing metallic annular elements to the structures.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1: shows a schematic representation of a one-piece long insulator having a low electric withstand;

(2) FIG. 2: shows a schematic representation of a multi-part insulator from the prior art for the interruption of flashovers along the surface of the insulator;

(3) FIG. 3: shows a graphic representation of the number of the insulator segments plotted against the segment length of the insulator segments, for a lightning impulse voltage of 390 kV;

(4) FIG. 4: shows a graphic representation of the overall insulator length plotted against the length of the insulator segments, for a lightning impulse load of 650 kV;

(5) FIG. 5: shows a schematic representation of a ceramic insulator according to the invention, having electrically conductive discharge path interrupters;

(6) FIG. 6: shows a vacuum interrupter having a ceramic insulator according to the invention, with electrically conductive discharge path interrupters.

DESCRIPTION OF THE INVENTION

(7) FIG. 1 shows a schematic and exemplary representation of a long, one-piece insulator 5 of a vacuum tube, having a vacuum side 2 and a gas side or outer side 3. At high voltages, a breakdown path 4 is formed along the surface of the insulator 5 on the vacuum side 2.

(8) This breakdown path is dictated in a vacuum by the desorption of adsorbed gas layers by field-emitted electrons.

(9) FIG. 2 shows a multi-part insulator 6, wherein the individual insulator segments of the insulator 6 are interrupted by metallic field control elements 7, and the metallic field control elements, at least on the vacuum side 2, project into the vacuum, thereby ensuring an interruption of the breakdown path.

(10) FIG. 3 shows a graphic representation of the total number of insulator segments Y1 plotted against the segment length of the insulator segments X1 in mm for the insulation of lightning impulse voltages of 390 kV. The minimum requisite number of the ceramic insulator segments for the insulation of lighting impulse voltages of 390 kV is thus represented as a function of segment length. For a solution involving a one-piece ceramic, a length of approximately 700 mm is thus required.

(11) FIG. 4 shows a graphic representation of the overall insulator length Y2 in mm plotted against the segment length of the insulators X2 in mm, for a lightning impulse load of 650 kV. The total insulator length of an insulator arrangement for lightning impulse loads of 650 kV is thus represented as a function of the length of the individual segments. For short insulator segments of e.g. 30 mm in length, total insulator lengths of less than 300 mm are thus possible.

(12) FIG. 5 shows a ceramic insulator 10 according to the invention, having a longitudinal extent 20 and a cavity 15 located in the ceramic insulator. The ceramic insulator comprises discharge path interrupters 12. On a first side 30 of the longitudinal extent 20, a first opening 31 is arranged and, on a second side 32 of the longitudinal extent 20, a second opening 33 is arranged.

(13) FIG. 6 shows a vacuum interrupter 1 according to the invention, having a fixed contact 38 which extends through a connecting means 40 through the sealed first opening 35. The moving contact 37 of the vacuum interrupter 1 is also represented, which extends through an appropriate connecting means 40in this case, a bellows-type or corrugated bushing is representedthrough the second sealed opening 36. The vacuum interrupter 1 further comprises a ceramic insulator 10 according to the invention, having discharge path interrupters 12. The fixed contact 38 and the moving contact 37 extend along the longitudinal extent 20.