High-voltage circuit breaker and method for electromagnetically shielding a vacuum interrupter in an insulator

Abstract

The invention relates to a high-voltage circuit breaker (1) and a method for electromagnetically shielding at least one vacuum interrupter (2) in an insulator (3) of a high-voltage circuit breaker (1). The high-voltage circuit breaker (1) comprises at least one vacuum interrupter (2) which is situated in an insulator (3) and which has at least one shield ring (4), the at least one shield ring (4) having, in a cross-sectional plane along an axis of rotation (5) of the shield ring (4), two cross-sections (6) which differ from a circular cross-section.

Description

[0001] The invention relates to a high-voltage circuit breaker and a method for electromagnetically shielding at least one vacuum interrupter tube in an insulator of a high-voltage circuit breaker. The high-voltage circuit breaker comprises at least one vacuum interrupter tube arranged in an insulator and having at least one shielding ring.

[0002] High-voltage circuit breakers are designed to switch voltages up to 1200 kV and currents up to several thousand amperes. They typically use switching gases such as SF6, which are harmful to the climate and / or contain toxic components. Achieving long-term stable, gas-tight insulation in high-voltage circuit breakers, reliably preventing gas leakage, is complex and increases maintenance costs. Circuit breakers using alternative switching gases, such as clean air (dry, purified air), require larger dimensions for the same design and maximum switching voltages or currents to ensure reliable electrical insulation between the conductive components, thus increasing costs. The use of vacuum interrupters in high-voltage circuit breakers, in conjunction with clean air as the insulating gas, is an alternative to, for example, [other solutions].Gas-insulated switches with nominal and arc contacts, including switching gases such as SF6. Vacuum interrupters are known, for example, from DE 10 2009 007474 A1, WO 2004 / 001783 A1, DE 103 08 573 A1 and the publication Karthik Reddy Venna ET AL: "A Simulation Analysis to Improve the Dielectric Strength Inside High Voltage Vacuum Interrupters", January 20, 2015 (2015-01-20), pages 1-128, XP093136914.

[0003] The vacuum interrupters can be arranged, or are arranged, in an outer insulator, which is, for example, column-shaped with circumferential ribs around its outer circumference to increase the electrical insulation along the outer surface in the direction of the longitudinal axis. The insulator is one-piece or multi-piece, in particular hollow cylindrical, and made, for example, of ceramic, silicone, and / or a composite material. During operation of the high-voltage circuit breaker, the insulator is arranged upright, for example, on a support frame or on a beam with a foundation. One or more vacuum interrupters are arranged, for example, along the longitudinal axis of the insulator, in particular coaxially with the longitudinal axis of the insulator, and are mechanically fixed within the insulator. The high-voltage circuit breaker can comprise more than one vacuum interrupter connected in series and / or parallel; for the sake of simplicity, however, only one vacuum interrupter will be considered in the following discussion.

[0004] The vacuum interrupter is mechanically stable and electrically conductive inside the insulator and connected between at least two external electrical terminals, the electrical terminals being, for example, terminal lugs for connecting high-voltage lines, generators, and / or electrical consumers. The design of a vacuum interrupter for high-voltage circuit breakers is known, for example, from EP 0 102 317 A2. The vacuum interrupter comprises a housing in the form of a circular, straight cylinder, which is evacuated internally. The housing consists of two identical, straight cylindrical halves made of ceramic or ceramic parts, which are joined by a metal cylinder or metal part with transition pieces in the center of the housing. The transition pieces serve as shielding electrodes or shielding within the housing.

[0005] The vacuum switching tube comprises at least one electrical contact with a fixed and a movable contact piece for switching. Alternatively, several movable contact pieces can be enclosed by the at least one electrical contact, with or without a fixed contact piece. For the sake of simplicity, the following description assumes a vacuum switching tube with one fixed and one movable contact piece. The contact pieces are disc-shaped within the vacuum switching tube and enclosed in a vacuum. The contact pieces extend externally in a bolt-like fashion and are each electrically connected to an external electrical terminal, e.g., a terminal lug of the high-voltage circuit breaker. The movable contact piece is movably guided and mounted within the vacuum switching tube by a bellows, creating a vacuum seal.

[0006] When switched on, the movable contact is moved towards the fixed contact until mechanical and electrical contact is established. When switched off, the movable contact is moved away from the fixed contact until the electrical contact is broken and sufficient clearance exists to prevent electrical arcing when voltage is applied. At high voltages, e.g., in the range of 145 kV, large distances between the contacts are necessary. The vacuum interrupter tube is designed to be long to ensure sufficient internal clearances. The straight, cylindrical halves of the vacuum interrupter tube housing, made of ceramic or ceramic components, are constructed from several parts joined together by metal components with transition pieces. These transition pieces act as shielding electrodes or shielding within the housing.The joining of ceramic parts of the housing to metal parts, which are made of copper and / or steel, is done, for example, by soldering.

[0007] Electromagnetic fields around the contacts are shielded within the vacuum interrupter by the shielding electrodes. Along the outer circumference of the vacuum interrupter, the metal components with transition pieces are each formed as a circular ring and serve as shielding for electromagnetic fields. The ring-shaped shields along the outer circumference of the vacuum interrupter are arranged in a plane perpendicular to a longitudinal axis of the vacuum interrupter and have two circular cross-sections in a section along this axis. To prevent electrical arcing between the ring-shaped shields or shielding rings of the vacuum interrupter via an inner wall of the outer insulator of the high-voltage circuit breaker, the shielding rings of the vacuum interrupter are positioned at a distance from the inner wall of the insulator.

[0008] Particularly in vacuum interrupters with cylindrical housing sections of the same diameter, the outer circumference of the vacuum interrupter is determined by the outer circumference of its shielding rings. The distance d of the shielding rings from the inner wall of the insulator, in conjunction with the ring diameter of the shielding rings, determines the circumference of the high-voltage circuit breaker's insulator. A larger circumference is associated with higher manufacturing costs and a greater material requirement for the insulator.

[0009] The object of the present invention is to provide a high-voltage circuit breaker and a method for electromagnetic shielding of at least one vacuum interrupter in an insulator of a high-voltage circuit breaker, which enable a reduced size of the insulator of the high-voltage circuit breaker compared to the prior art, lower manufacturing costs and lower material costs for the insulator.

[0010] The stated problem is solved according to the invention by a high-voltage circuit breaker with the features according to claim 1 and / or by a method for electromagnetically shielding at least one vacuum interrupter in an insulator of a high-voltage circuit breaker, in particular a previously described high-voltage circuit breaker, according to claim 8. Advantageous embodiments of the high-voltage circuit breaker according to the invention and / or of the method according to the invention for electromagnetically shielding at least one vacuum interrupter in an insulator of a high-voltage circuit breaker, in particular a previously described high-voltage circuit breaker, are specified in the dependent claims.

[0011] A high-voltage circuit breaker according to the invention comprises at least one vacuum interrupter tube arranged in an insulator and at least one shielding ring. The at least one shielding ring has two cross-sections deviating from a circular cross-section in a section plane along an axis of rotation of the shielding ring. In this context, the axis of rotation of the shielding ring is defined as the axis perpendicular to the plane of the ring and passing through the center of the circular ring.

[0012] Cross-sections deviating from a circular cross-section allow for good shielding of the vacuum interrupter tube, a smaller outer circumference of the vacuum interrupter tube compared to vacuum interrupter tubes with shielding rings with circular cross-sections, and thus a smaller circumference of the insulator of the high-voltage circuit breaker, resulting in lower manufacturing costs and less material required for the insulator.

[0013] At least one of the shielding rings has two rectangular cross-sections with rounded corners in the plane of rotation. Such cross-sections, while providing the same shielding effect, have a smaller diameter in one direction than circular cross-sections, offering the advantages described above.

[0014] The at least one vacuum switching tube can be cylindrical in shape, and the insulator can be cylindrical in shape with a circular base, wherein the at least one vacuum switching tube can be arranged coaxially within the insulator. The axis of rotation of the at least one shielding ring can be coaxial with the longitudinal axis of the at least one vacuum switching tube. This ensures that the shielding rings of the vacuum switching tube maintain the same, and in particular minimal, distance to the inner wall of the insulator along their entire circumference. The insulator can be designed with a minimal circumference, offering the advantages described above.

[0015] The at least one shielding ring can be arranged circumferentially around the outer circumference of the at least one vacuum interrupter tube, and in particular can be mechanically and stably connected to the at least one vacuum interrupter tube. This allows changes in the position of the at least one shielding ring during operation of the high-voltage circuit breaker to be prevented.e.g. mechanical vibrations can be avoided, and electrical flashovers can be prevented by changing the distances between the shielding rings.

[0016] The cross-sections of the at least one shielding ring can be flattened in the plane of rotation of the at least one shielding ring in the direction of the at least one vacuum switching tube and / or in the direction of the inner wall of the insulator. Such cross-sections, while providing the same shielding effect, have a smaller diameter in the direction of the vacuum switching tube and / or the inner wall of the insulator than circular cross-sections, with the advantages described above.

[0017] Two, four, or at least six shielding rings can be included. Particularly with a regular arrangement of the shielding rings along the longitudinal axis of the vacuum switching tube on its outer circumference, good electromagnetic shielding of the vacuum switching tube, especially from the outside, can be achieved.

[0018] The at least one shielding ring can be mechanically and / or electrically connected to at least one shielding electrode inside the at least one vacuum switching tube. This allows for good electromagnetic shielding of the vacuum switching tube, particularly from the outside, and enables the shielding electrode inside the at least one vacuum switching tube and the at least one shielding ring to be mechanically and stably fixed.

[0019] The at least one shielding ring can be made of a conductive material, in particular a metal, especially copper and / or steel, or a conductive plastic, or a plastic with conductive particles, especially silicone with carbon black particles. Copper and steel exhibit good electrical conductivity and, given their shape, provide good shielding or attenuation of electromagnetic fields. The same applies to conductive plastics and / or plastics with conductive particles, such as silicone with carbon black particles. In particular, attenuated induced currents in the shielding ring and / or an influence on the field line pattern of an electromagnetic field can enable good shielding.

[0020] At least one shielding ring has a minimum and / or maximum distance d to the inner wall of the insulator, ranging from millimeters to a few centimeters. Such a distance d prevents arcing between shielding rings across the inner wall of the insulator, particularly when the insulator is filled with an insulating gas such as Clean Air.

[0021] An inventive method for electromagnetic shielding of at least one vacuum interrupter in an insulator of a high-voltage circuit breaker, in particular in a previously described high-voltage circuit breaker, comprises electromagnetic shielding of the at least one vacuum interrupter by at least one shielding ring, the two cross-sections of which are flattened in the plane of rotation adjacent to the at least one vacuum interrupter and / or adjacent to the insulator, compared with the cross-section in the direction parallel to the axis of rotation.

[0022] The advantages of the inventive method for electromagnetic shielding of at least one vacuum interrupter in an insulator of a high-voltage circuit breaker, in particular of a previously described high-voltage circuit breaker, according to claim 11 are analogous to the previously described advantages of the inventive high-voltage circuit breaker according to claim 1 and vice versa.

[0023] In the following, exemplary embodiments of the invention are schematically described in the Figures 1 to 4 shown and described in more detail below.

[0024] This shows Figure 1 schematically shows a high-voltage circuit breaker 1 according to the invention in sectional view from one side, with shielding rings 4 of the vacuum switching tube 2 having cross-sections 6 deviating from a circular cross-section, and Figure 2 schematically shows an enlarged section of a shielding ring 4 in sectional view. Figure 1with elliptical cross-sections 6, and Figure 3 schematically shows an enlarged section of a shielding ring 4 in sectional view. Figure 1 with oval, racetrack-like cross-sections 6, and Figure 4 schematically shows an enlarged section of a shielding ring 4 in sectional view. Figure 1 with rectangular cross-sections 6 with rounded corners.

[0025] In Figure 1 The figure shows a schematic cross-sectional view of a section of a high-voltage circuit breaker 1 according to the invention, viewed from one side. The high-voltage circuit breaker 1 comprises a vacuum interrupter 2, which is arranged in an insulator 3. The insulator 3 is filled, for example, with clean air as insulating gas, and the vacuum interrupter 2 is arranged with its longitudinal axis 5 coaxial to the longitudinal axis 5 of the insulator 3, spaced apart from the insulator 3. The minimum distance d between the vacuum interrupter 2 and the inner wall 7 of the insulator is, for example, in the range of millimeters or centimeters.

[0026] The high-voltage circuit breaker 1 is constructed analogously to high-voltage circuit breakers that include rated and arc contacts and are filled, for example, with SF6, except that instead of rated and arc contacts, a vacuum interrupter 2 is included, and, for example, clean air is used as the insulating gas. The insulator 3 is made, for example, of ceramic, silicone, and / or an electrically insulating composite material. The insulator 3 is columnar, cylindrical, or hollow, with annular ribs along its outer circumference, offering the advantages described above. The base and top surfaces of the columnar insulator 3 are hermetically sealed and each is provided with external electrical connections of the high-voltage circuit breaker 1, which is not shown in the figures for the sake of simplicity.

[0027] The vacuum interrupter 2 is mechanically fixed within the insulator 3 in the area of ​​its base and top surfaces, particularly by means of supports, and electrically connected to the external terminals of the high-voltage circuit breaker 1, which is also not shown in the figures for the sake of simplicity. A drive, e.g., a spring-loaded drive, can electrically switch the vacuum interrupter 2 via elements of a kinematic chain, e.g., gears, release mechanisms, and / or a switching rod, in particular by moving a movable contact element within the vacuum interrupter 2 towards and / or away from a fixed contact element. The high-voltage circuit breaker 1 can be designed as a multi-pole switch, in particular as a three-pole switch with three vacuum interrupters 2, each arranged in an insulator 3.Alternatively or additionally, several vacuum interrupters 2 can be connected in series and / or parallel, arranged in one insulator 3 or in different insulators 3. An arrangement can be made with insulator columns standing vertically on one or more supports, and / or in a T-support shape, with an insulator 3 arranged on each side of the T-shape as an arm of the T-shape.

[0028] As previously described, the vacuum switching tube 2 comprises a housing in the form of a circular, straight cylinder, which is evacuated internally. The housing is constructed of, in particular, identical, straight cylindrical ceramic parts, which are joined together via metal parts with transition pieces. The transition pieces function as shielding electrodes or shields within the housing and are mechanically bonded to the ceramic parts, in particular by soldering. In the outer region of the vacuum switching tube 2, the transition pieces have a ring shape, which serves as shielding rings 4. In the central region of the vacuum switching tube 2, where, in particular, disc-shaped ends of the contact pieces are located inside the vacuum switching tube 2, a cylindrical, metallic shield is arranged between two shielding rings 4 instead of a ceramic part.

[0029] The shielding rings 4 are each arranged in a plane perpendicular to the longitudinal axis 5 of the vacuum switching tube 2 on the outer circumference of the vacuum switching tube 2, spaced apart from each other along the longitudinal axis 5 of the vacuum switching tube 2. The distance between adjacent shielding rings 4 can be in the range of centimeters to meters, particularly with shielding rings 4 arranged regularly along the longitudinal axis 5 of the vacuum switching tube 2. Figure 1A section through a shielding ring 4 on one side is shown in a dashed-bordered area. The section is made in a plane in which the longitudinal axis 5 of the vacuum switching tube and the rotational axis 5 of the shielding ring 4 lie. In the section, the cross-section 6 of the shielding ring 4 does not have a circular shape according to the invention, but is flattened parallel to the inner wall 7 of the insulator 3 and parallel to the cylindrical circumference of the vacuum switching tube 2, i.e., it has a smaller or no curvature in the direction of the inner wall 7 of the insulator 3 and in the direction of the cylindrical circumference of the vacuum switching tube 2. "In the direction of" is to be denoted as adjacent.

[0030] In the Figures 2 to 4 is the cut through the shielding ring 4, as shown in the dashed outline area of ​​the Figure 1 depicted, shown enlarged. In the background example of Figure 2The shielding ring 4 has an elliptical shape in the cross-sectional plane of the rotation axis 5 or the longitudinal axis of the vacuum switching tube 2 and / or the insulator 3. In the background example of Figure 3 The shielding ring 4 has an oval, racetrack-like shape in the cross-sectional plane of the rotation axis 5. In the embodiment of Figure 4 The shielding ring 4 has a rectangular shape with rounded corners in the plane of rotation 5. The shape of the shielding rings 4 achieves optimal shielding of electromagnetic fields with a minimal diameter in the direction perpendicular to the axis 5. This allows the inner and outer diameters of the insulator 3 to be reduced compared to shielding rings 4 with a circular cross-section or with two circular cross-sections in the plane of the axis 5, while maintaining the same distance d between the inner wall 7 of the insulator 3 and the shielding rings 4 or the vacuum switching tube 2.

[0031] For example, the transition pieces can be formed as a separate part within the shielding rings 4, e.g., pressed in, soldered, welded, and / or glued on. Alternatively, the transition pieces and shielding rings 4 can each be manufactured as a single unit, particularly from a sheet of metal, e.g., copper and / or steel. The spacing between the shielding rings 4 can be regular, especially with the shielding rings 4 arranged parallel to each other. Alternatively, for example, a metal cylinder can be arranged in the central region of the vacuum switching tube 2 instead of ceramic cylinders, with the shielding rings 4 being formed or attached directly to the metal cylinder, and the spacing of the shielding rings 4 in this region differing from the spacing of the shielding rings in the region of interconnected ceramic cylinders.The shielding rings 4 can also be arranged at irregular intervals, in particular along the length of a cylindrical vacuum switching tube 2. The vacuum switching tube 2 and / or the shielding rings 4 can enclose a circular area, i.e., the base and top surfaces of the vacuum switching tube 2 are circular. Alternatively, the vacuum switching tube 2 and / or the shielding rings 4 can enclose a different area, e.g., an elliptical area. Reference symbol list

[0032] 1 High-voltage circuit breaker 2 Vacuum switching tube 3 Insulator 4 Shielding ring 5 Shaft 6 Cross-section 7 Inner wall of the insulator d Distance of the shielding ring (4) to the inner wall of the insulator (3)

Claims

1. A high-voltage circuit breaker (1) having at least one vacuum interrupter (2) which is arranged in an insulator (3) and comprises at least one shield ring (4), wherein the at least one shield ring (4) has, in a sectional plane along an axis of rotation (5) of the shield ring (4), two cross-sections (6) which differ from a circular cross-section, characterised in that the at least one shield ring (4) has a minimum and / or maximum distance (d) from the inner wall of the insulator (3) ranging from millimetres up to a few centimetres, and in that the at least one shield ring (4) has, in the sectional plane of the axis of rotation (5), two rectangular cross-sections (6) with rounded corners.

2. The high-voltage circuit breaker (1) according to claim 1, characterised in that the at least one vacuum interrupter (2) is formed in a circular-cylindrical shape, and in that the insulator (3) is formed in a hollow-cylindrical shape, with a circular base area, wherein the at least one vacuum interrupter (2) is arranged coaxially in the insulator (3).

3. The high-voltage circuit breaker (1) according to any one of the preceding claims, characterised in that the axis of rotation (5) of the at least one shield ring (4) is coaxial to the longitudinal axis (5) of the at least one vacuum interrupter (2).

4. The high-voltage circuit breaker (1) according to any one of the preceding claims, characterised in that the at least one shield ring (4) is arranged circumferentially around the outer circumference of the at least one vacuum interrupter (2), in particular connected to the at least one vacuum interrupter (2) in a mechanically stable manner.

5. The high-voltage circuit breaker (1) according to any one of the preceding claims, characterised in that two, four or at least six shield rings (4) are comprised.

6. The high-voltage circuit breaker (1) according to any one of the preceding claims, characterised in that the at least one shield ring (4) is mechanically and / or electrically connected to at least one shield electrode inside the at least one vacuum interrupter (2).

7. The high-voltage circuit breaker (1) according to any one of the preceding claims, characterised in that the at least one shield ring (4) is formed from a conductive material, in particular a metal, in particular copper and / or steel, or a conductive plastic material, or plastic material with conductive particles, in particular silicone with soot particles.

8. A method for electromagnetically shielding at least one vacuum interrupter (2) in an insulator (3) of a high-voltage circuit breaker (1) according to any one of the preceding claims, with electromagnetic shielding of the at least one vacuum interrupter (2) by at least one shield ring (4), the two cross-sections (6) of which in the sectional plane of the axis of rotation (5) extend flat adjacent to the at least one vacuum interrupter (2) and / or adjacent to the insulator (3) compared to the cross-section in a direction parallel to the axis of rotation (5), wherein the at least one shield ring (4) has, in the sectional plane of the axis of rotation (5), two rectangular cross-sections (6) with rounded corners.

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