Vacuum circuit breaker

Abstract

To provide an improved concept for a vacuum circuit breaker in which the vacuum circuit breaker is shielded from the disturbing influence of surrounding external magnetic fields and which ensures safe (reliable) operation of the tap changer. [Solution] A vacuum circuit breaker (1) for a tap changer, comprising a metallic shielding portion (2) from external magnetic fields formed in a hollow cylindrical shape and arranged around at least a portion of the cylindrical jacket surface of the vacuum circuit breaker (1), and a bracket (4) arranged outside the metallic shielding portion (2) and the vacuum circuit breaker (1) and surrounding them at least partially coaxially, the bracket (4) having a plurality of retaining elements (5) that hold the metallic shielding portion (2) in a predetermined position depending on the vacuum circuit breaker (1).

Description

[Technical Field]

[0001] The present invention relates to a vacuum circuit breaker for a tap changer for changing between different taps of a transformer and to a tap changer comprising such a vacuum circuit breaker. [Background technology]

[0002] The use of vacuum circuit breakers as switching elements in tap changers, in particular on-load tap changers, for seamless switching under load between winding taps of a tapped transformer has been known from the prior art for decades, for example from US Pat. No. 5,629,999.

[0003] Basically, vacuum interrupters exist in the field of high voltage technology in a wide variety of construction forms and fields of application, for example as circuit breakers.

[0004] It is known that a vacuum interrupter may be externally affected by a magnetic field depending on the magnitude of the current from the circuit breaker. Patent Document 2 proposes a shielding part that protects the vacuum interrupter from the effect of the external magnetic field.

[0005] Such magnetic fields can be generated by the transformer depending on the configuration and design of the transformer and the influence of the tap changer on the vacuum interrupter. Such external influences can negatively affect the life of the vacuum interrupter as they can lead to asymmetrical burning of the contacts and asymmetrical vaporization of the insulating sections in the vacuum interrupter. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 96 / 30922 [Patent Document 2] DE 19518533 Summary of the Invention [Problem to be solved by the invention]

[0007] It is therefore an object of the present invention to provide an improved concept for a vacuum circuit breaker, in which the vacuum circuit breaker is shielded from the disruptive influence of surrounding external magnetic fields and which ensures safe (reliable) operation of the tap changer. [Means for solving the problem]

[0008] The problem is solved by the subject matter of the respective independent claims. Further embodiments are the subject matter of the dependent claims.

[0009] The improved concept is based on the idea of ​​providing the vacuum interrupter with a metallic shield against external magnetic fields.

[0010] According to an improved concept, a vacuum interrupter for a tap changer is provided which includes a metallic shield and bracket against external magnetic fields.

[0011] The metallic shield is hollow cylindrical and is arranged around at least a portion of the cylindrical jacket surface of the vacuum interrupter. Preferably, the hollow cylindrical shield is arranged on the vacuum interrupter at the center in the axial direction of the vacuum interrupter, at least half the height of the cylindrical jacket surface of the vacuum interrupter. The shield can be made of one or more pieces and is made of, for example, soft iron.

[0012] The bracket is disposed externally of the metallic shield and the vacuum interrupter and at least partially coaxially surrounds the metallic shield and the vacuum interrupter, preferably the vacuum interrupter is coaxially surrounded by the bracket by at least 240°.

[0013] Additionally, the bracket includes a plurality of retaining elements that rely on the vacuum interrupter to hold the metallic shield in place.

[0014] According to at least one embodiment, the retaining element includes at least two protrusions projecting radially inward, which protrusions form stops for the first and second ends of the metallic shielding part.

[0015] This allows the metallic shielding part to be positioned on the vacuum interrupter preferably centrally in the axial direction of the vacuum interrupter.

[0016] According to at least one alternative embodiment, at least one of the protrusions includes a spacer disposed between the metallic shield and the vacuum interrupter.

[0017] The spacer is formed as a wedge-shaped projection, which is located radially inwardly of the at least one protrusion and extends in the axial direction of the vacuum interrupter, and when the bracket is attached, the spacer is located between the shield and the vacuum interrupter and prevents the shield from resting directly on the cylindrical jacket surface of the vacuum interrupter.

[0018] According to at least one embodiment, the retaining element further includes at least one protrusion that protrudes radially inward, the protrusion protruding in an engaging manner, i.e., fitting snugly, into the opening of the metal shield.

[0019] This holds the shield in place and prevents twisting of the shield relative to the vacuum interrupter.

[0020] According to at least one embodiment, the bracket includes at least one inwardly facing step at each of the first and second ends, which step engageably contacts the vacuum interrupter.

[0021] The steps can be formed radially around the end of the bracket and / or can be formed radially segmented, i.e., consisting of individual steps spaced apart from one another and positioned radially at the end of the bracket.

[0022] According to at least one embodiment, the bracket includes a plurality of inwardly extending reinforcement portions at each of the first and second ends, the reinforcement portions engagingly contacting the vacuum interrupter, and the bracket is secured axially to the vacuum interrupter using the reinforcement portions.

[0023] According to at least one alternative embodiment, the bracket is comprised of at least two segments, each of which is identically formed and includes a plurality of transverse and longitudinal reinforcements, and which are preferably arranged at a 180° horizontal and vertical angle relative to one another.

[0024] According to at least one other embodiment, the vacuum interrupter includes a retaining ring that is removably mechanically coupled to the bracket such that the retaining ring can be snapped onto the bracket and captured in the bracket by twisting.

[0025] The fixing ring is supported at its end face on the vacuum circuit breaker, and fixes the bracket in the axial direction of the vacuum circuit breaker by a capture mechanism.

[0026] According to the improved concept there is also provided a tap changer, in particular an on-load tap changer, which comprises at least one vacuum circuit breaker according to the improved concept.

[0027] According to at least one embodiment of the tap changer, the tap changer comprises a diverter switch comprising a vacuum interrupter or a load selector comprising a vacuum interrupter.

[0028] The present invention will be described in detail below based on exemplary embodiments with reference to the drawings. Components that are identical or functionally identical or have the same effect may be labeled with the same reference numerals. Identical components or components with the same function are, if necessary, only described with reference to the drawings in which they are depicted. The description is not necessarily repeated in the following figures. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a perspective view of an exemplary embodiment of an improved concept vacuum interrupter; [Figure 2] FIG. 2 is a longitudinal section of the vacuum circuit breaker according to FIG. [Figure 3] 1 is a perspective view of an exemplary embodiment of a segment of a bracket for a vacuum interrupter according to an improved concept; [Figure 4] FIG. 10 is a detailed perspective view of another exemplary embodiment of an improved concept vacuum interrupter; DETAILED DESCRIPTION OF THE INVENTION

[0030] 1 and 2 show a perspective view and a longitudinal section of an exemplary embodiment of an improved concept vacuum interrupter.

[0031] The vacuum circuit breaker 1 comprises a housing having an arc chamber (switching chamber) 8 made of, for example, ceramic, and two wall portions 9 made of, for example, metal and arranged on the end faces thereof. The arc chamber 8 is formed in a hollow cylindrical shape and has a cylindrical jacket surface. The wall portions 9 are adjacent to the arc chamber 8 on the end faces thereof and hermetically seal the arc chamber.

[0032] The vacuum circuit breaker 1 includes a fixed contact 11 and a contact 12 that is movable in the axial direction relative to the vacuum circuit breaker. The contacts 11 and 12 are arranged in an arc chamber 8. By operating the movable contact 12, the vacuum circuit breaker 1 can be opened or closed.

[0033] A hollow cylindrical metallic shielding part 2 is arranged around a part of the vacuum circuit breaker 1, more precisely around a part of the cylindrical jacket surface of the arc chamber 8 along the axis A and centrally with respect to the height of the arc chamber 8.

[0034] The bracket 4 surrounds the vacuum interrupter 1 and the shielding part 2 from the outside coaxially by about 240°. The remaining parts of the vacuum interrupter 1 and the shielding part 2 are not contacted by the bracket 4.

[0035] A plurality of reinforcing portions 44 extending radially inward are arranged on the first end 41 and the second end 42 of the bracket 4, and when the bracket 4 is installed, these reinforcing portions come into engaging contact with the vacuum circuit breaker 1 or the wall portion 9 on the end face side, thereby fixing the bracket 4 with respect to the axis A.

[0036] The bracket 4 is made up of two segments that are identical to each other and have a number of lateral reinforcements 13 and longitudinal reinforcements 14. The two segments are twisted 180° horizontally and vertically relative to each other.

[0037] FIG. 3 shows such a segment of the bracket 4 in detail in a perspective view.

[0038] The brackets 4 or segments are provided with holding elements by means of which they come into contact with the vacuum interrupter 1 or arc chamber 8 and wall 9 and shield 2 .

[0039] The radially arranged longitudinal reinforcements 14 have a number of radially inwardly projecting projections 5 which are arranged at the level of the first end 21 and the second end 22 of the shielding part 2. The projections form upper and lower stops for the shielding part 2 and fix the shielding part relative to the axis A.

[0040] Adjacent protrusions 5 arranged on the longitudinal reinforcement 14 at the level of the second end 22 of the shield 2 are partially connected to one another to form an additional partial reinforcement 15. The protrusions 5 connected to one another via the partial reinforcement 15 are provided with a spacer 16. This spacer is formed as a wedge-shaped projection, which extends in the axial direction of the vacuum interrupter 1, tapers towards the first end 41 of the bracket 4 and is arranged radially inside the partial reinforcement 15 of the protrusions 5. When the bracket 4 is mounted, the wedge-shaped projection is arranged between the shield 2 and the vacuum interrupter 1, more precisely the arc chamber 8, so that the shield 2 does not rest directly on the cylindrical jacket surface of the shield 2.

[0041] Another retaining element is a radially inwardly projecting stud 6, which is arranged centrally in one of the longitudinal reinforcements 14 of the bracket 4. The stud 6 cooperates in an engaging manner with an opening 23 in the shield 2, thereby preventing twisting of the shield 2 depending on the vacuum interrupter 1.

[0042] Each of the segments of the bracket 4 has an inwardly positioned collar 43 at a first end 41 and a second end 42, which has a step 7 disposed radially inward. The step 7 contacts the vacuum circuit breaker 1 or a wall 9 on the end face side of the vacuum circuit breaker 1.

[0043] Furthermore, in order to stabilize the bracket 4 in the vacuum circuit breaker 1, a cable tie 17 is arranged at each of the first end 41 and the second end 42 at the height of the collar portion 43 (see FIG. 1).

[0044] FIG. 4 shows a detailed perspective view of an exemplary embodiment of an improved concept vacuum interrupter.

[0045] A fixing ring 3 is arranged at the first end 41 of the bracket 4 and is supported on the end wall 9 of the first end 41. The fixing ring 3 is detachably mechanically coupled to the bracket 4 according to the bayonet coupling principle so that the fixing ring 3 can be snapped into a collar 43 at the first end 41 of the bracket 4 and can be captured by twisting at the collar. In this way, the bracket 4 is fixed with respect to the axis A.

[0046] It is believed that the present disclosure and many of its attendant advantages will be understood from the foregoing description. It will be apparent that various changes in the form, construction, and arrangement of the elements may be made without departing from the disclosed subject matter or sacrificing all of its substantial advantages. The above-described embodiments are merely illustrative, and such changes are intended to be encompassed within the scope of the appended claims. It should be understood that the present invention is defined by the appended claims. The present invention may also be applied to the following aspects: 1. A vacuum circuit breaker (1) for a tap changer, comprising a metallic shield (2) from external magnetic fields, formed in the shape of a hollow cylinder and arranged around at least a part of the cylindrical jacket surface of the vacuum circuit breaker (1), and a bracket (4) arranged outside the metallic shield (2) and the vacuum circuit breaker (1) and at least partially coaxially surrounding them, the bracket (4) having a number of holding elements (5, 6) for holding the metallic shield (2) in a predetermined position depending on the vacuum circuit breaker (1). 2. A vacuum circuit breaker as described in claim 1, characterized in that the retaining element includes at least two protrusions (5) projecting radially inward, which protrusions form stops for the first end (21) and the second end (22) of the metallic shielding part (2). 3. A vacuum circuit breaker as described in 2. above, characterized in that at least one of the protrusions (5) is provided with a spacer (16) arranged between the metallic shielding portion (2) and the vacuum circuit breaker (1). 4. A vacuum circuit breaker as described in any one of 1. to 3. above, characterized in that the retaining element includes at least one stud (6) projecting radially inward, the stud projecting in an engaging manner into an opening (23) in the metal shielding part (2). 5. A vacuum circuit breaker as described in any one of 1. to 4. above, characterized in that the bracket (4) includes at least one radially circumferentially arranged and / or radially segmented step (7) at each of the first end (41) and the second end (42), facing radially inward, and the step is in engaging contact with the vacuum circuit breaker. 6. A vacuum circuit breaker as described in 5. above, characterized in that the bracket (4) includes a plurality of reinforcing portions (44) extending radially inward at each of the first end (41) and the second end (42), and the reinforcing portions are in engaging contact with the vacuum circuit breaker. 7. A vacuum circuit breaker according to any one of the above items 1 to 6, characterized in that the bracket (4) comprises a plurality of lateral reinforcing portions (13) and longitudinal reinforcing portions (14). 8. A vacuum circuit breaker according to any one of 1. to 7. above, characterized in that the vacuum circuit breaker (1) further comprises a fixing ring (3), which is detachably mechanically coupled to the bracket (4) so ​​that the fixing ring (3) can be fitted into the bracket (4) and can be captured by twisting it in the bracket. 9. A tap changer including the vacuum circuit breaker according to any one of 1. to 8. above. 10. A tap changer as set forth in claim 9, characterized in that the tap changer comprises a diverter switch or load selector including a vacuum circuit breaker (1). [Explanation of symbols]

[0047] 1. Vacuum circuit breaker 2 Shielding part 3 Retaining ring 4 Bracket 5 Protrusion 6 studs 7 Steps 8 Arc Chamber 9 End wall 11 Fixed contacts 12 Movable contacts 13 Lateral reinforcement 14 Longitudinal reinforcement 15 Partial reinforcement part 16 spacer 17 Cable ties 21, 22 First end and second end of the shielding portion 23 Shielding opening 41, 42 First end and second end of bracket 43 Bracket collar 44 Bracket reinforcement

Claims

1. 1. A vacuum circuit breaker (1) for a tap changer, comprising: a metallic shield (2) formed in the shape of a hollow cylinder and arranged around at least a portion of the cylindrical jacket surface of the vacuum circuit breaker (1) from external magnetic fields; and a bracket (4) arranged outside the metallic shield (2) and the vacuum circuit breaker (1) and at least partially coaxially surrounding them, the bracket (4) having a plurality of retaining elements (5, 6) for holding the metallic shield (2) in a predetermined position depending on the vacuum circuit breaker (1), the retaining element including at least one stud (6) projecting radially inward, the stud projecting in an engaging manner into an opening (23) in the metallic shield (2).

2. 2. A vacuum circuit breaker according to claim 1, characterized in that the retaining element comprises at least two projections (5) projecting radially inward, said projections forming stops for the first end (21) and the second end (22) of the metallic shielding part (2).

3. 3. The vacuum interrupter according to claim 2, characterized in that at least one of the protrusions (5) comprises a spacer (16) arranged between the metallic shield (2) and the vacuum interrupter (1).

4. 4. The vacuum circuit breaker according to claim 1, wherein the bracket (4) is radially circumferentially arranged and / or radially segmented at the first end (41) and the second end (42), respectively, and includes at least one radially inwardly directed step (7), which is in engaging contact with the vacuum circuit breaker.

5. 5. The vacuum circuit breaker according to claim 4, wherein the bracket (4) includes a plurality of reinforcing portions (44) extending radially inward at the first end (41) and the second end (42), respectively, and the reinforcing portions are in engaging contact with the vacuum circuit breaker.

6. 6. Vacuum circuit breaker according to any one of claims 1 to 5, characterized in that the bracket (4) comprises a plurality of transverse reinforcements (13) and longitudinal reinforcements (14).

7. 7. The vacuum circuit breaker according to claim 1, further comprising a fixing ring (3) which is detachably mechanically coupled to the bracket (4) such that the fixing ring (3) can be fitted into the bracket (4) and can be captured by twisting in the bracket.

8. A tap changer comprising a vacuum circuit breaker according to any one of claims 1 to 7.

9. 9. A tap changer according to claim 8, characterized in that it comprises a diverter switch or load selector including a vacuum circuit breaker (1).

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