Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/662—Housings or protective screens
  • H01H33/66261—Specific screen details, e.g. mounting, materials, multiple screens or specific electrical field considerations
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/662—Housings or protective screens
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/662—Housings or protective screens
  • H01H33/66207—Specific housing details, e.g. sealing, soldering or brazing
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/662—Housings or protective screens
  • H01H33/66207—Specific housing details, e.g. sealing, soldering or brazing
  • H01H2033/6623—Details relating to the encasing or the outside layers of the vacuum switch housings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/662—Housings or protective screens
  • H01H33/66261—Specific screen details, e.g. mounting, materials, multiple screens or specific electrical field considerations
  • H01H2033/66284—Details relating to the electrical field properties of screens in vacuum switches

Definitions

• the present disclosure generally relates to vacuum interrupters.
• a gas-tight enclosure or container that houses a stationary and a moveable contact is made of a ceramic material.
• Lids at the axial ends of the container are typically made of a conductive material such as metal and joined to the container.
• a gas typically air
• three different materials the insulating material of the container, the conductive material of the lid and the surrounding gas
• a so-called "triple point” is formed. Electric field lines tend to concentrate in such a "triple point" area, i.e. the dielectric stress is comparatively high. There is a desire to alleviate the dielectric stress.
• a vacuum interrupter includes a stationary contact, a moveable contact, a vacuum-tight housing, and a field controller.
• the moveable contact is moveable relative to the stationary contact along an axis.
• the vacuum-tight housing accommodates the stationary contact and the moveable contact.
• the housing includes a container, a lid part, and a positioning surface.
• the container is made of an insulating material.
• the container extends along the axis.
• the container includes an axial end.
• the lid part is made of a conductive material. The lid part extends in the axial direction at least up to the axial end of the container.
• the field controller includes a conductive shielding part and an abutment part.
• the abutment part is provided at a distance from the shielding part.
• the abutment part abuts on the positioning surface such that the shielding part - at least partially - shields the radial step.
• the shielding part is spatially separated from the axial end.
• Abutting may include any kind of physical contact between the abutment part and the positioning surface, and may typically include a close contact between these parts.
• the field controller has substantially a round plate shape.
• Round as used herein, includes a substantially circular shape or an oval shape.
• the field controller has a "cup" shape in which a substantially round plate having a central hole includes an annular rim extending axially away from the round plate to form the shielding part.
• the positioning surface is formed on the lid part.
• the field controller having a substantially round plate shape such as a "cup" shape
• the substantially round plate having a central hole includes an annular rim extending axially away from the round plate, and the substantially round plate may at least partially form the positioning surface.
• the abutment part may then typically be formed as an abutment surface, and the abutment surface may be in close physical contact with the positioning surface. This may help to achieve a particularly precise positioning of the field controller, and in particular the shielding part thereof, relative to the positioning surface.
• the field controller has substantially a ring shape.
• a ring shape as used herein, includes a substantially circular circumferential shape or an oval circumferential shape.
• the field controller is a ring surrounding an exterior surface, or outer circumferential surface, of the lid part.
• the positioning surface at least partially coincides with the axial end.
• the field controller having substantially a ring form, for example a ring surrounding the exterior surface of the lid part, abuts, at the abutment part, on the axial end, wherein the axial end functions as the positioning surface.
• the shielding part includes a bulge.
• the bulge protrudes, or bulges, radially outwards.
• a bulge has a substantially convex shape and may also be described as a round or rounded rim substantially without any sharp edges. The bulge may help to alleviate a concentration of dielectric field lines, i.e. a dielectric stress.
• the shielding part extends beyond the radial step. That is, in the axial direction, the shielding part "climbs" over the radial step area without having a physical contact with the radial step area.
• the shielding part covers the radial step without any physical contact with the radial step. Such a configuration may improve the shielding even further.
• the vacuum interrupter further includes a non-conductive housing that accommodates the container, the metal flange, and the conductive shield. It has been found that such a non-conductive housing may have an impact on the field line concentration, i.e. the dielectric stress, in the "triple point" are described above.
• the conductive shield may help to alleviate the dielectric stress even when such a non-conductive housing is present.
• the container or the lid part or both have a substantially cylindrical shape.
• a cylindrical shape may facilitate the manufacturing, the mounting, or both, of the container and the lid part.
• the container is made of a ceramic material. Ceramics typically have excellent insulative properties and may thus be preferable particularly in medium voltage or high voltage applications.
• the shielding part is made of a metal material.
• Metals typically have excellent conductive properties and may thus be preferable when it comes to shielding dielectric stress arising from an application of the vacuum interrupter to medium voltage or high voltage.
• the lid part has a galvanic connection with the field controller.
• the galvanic connection extends through a body part of the field controller to the shielding part, and the shielding part of the field controller has, via the galvanic connection, substantially the same electrical potential as the lid part.
• the galvanic connection may be imparted by the positioning surface abutting on the abutment part, e.g. by being in close physical contact with each other.
• the vacuum interrupter includes two lids, that is one at each of its axial ends.
• the vacuum interrupter further includes a first field controller having substantially a ring shape, as described herein.
• the vacuum interrupter further includes a second field controller having substantially a round plate shape, as described herein.
• the first field controller is arranged at one of the lids, and the second field controller is arranged at the other one of the lids.
• the first field controller is arranged on the moving side contact side, and the second field controller is arranged on the stationary contact side of the vacuum interrupter.
• a vacuum interrupter is typically used in a wide variety of switchgear, e.g. compact medium and high voltage switchgear, insulated or not by gas.
• a part of a vacuum interrupter 100 is shown e.g. in Fig. 1 .
• the vacuum interrupter 100 includes a stationary contact 110 (a fixed contact) and a moveable contact 120 (a non stationary contact) opposing each other to form a contacting area. By moving the moveable contact away from the stationary contact, a space in between the contacts in the contacting area increases and interrupts a current flowing through the contacts 110, 120.
• the contacts 110, 120 are accommodated in a vacuum-tight housing including a container 130 of an insulating material extending along an axis A, and lid parts 140 of a conductive material on each axial-end side of the container 130.
• FIG. 1 shows a schematic sectional view of an embodiment of a vacuum interrupter 100 according to the present disclosure.
• Fig. 2 shows an enlarged view of a lower-left corner part of the vacuum interrupter 100 shown in Fig. 1 ; for convenience and better overview, some parts have been omitted in Fig. 2 . Furthermore, for convenience, Figs. 1 and 2 are described here in common.
• a dielectric medium (insulating gas) used in the vacuum interrupter 100 is a gas having a global warming potential lower than that of SF 6 .
• the dielectric medium comprises one or more of air, dry air, nitrogen (N 2 ), carbon dioxide (CO 2 ).
• the dielectric medium is one of air, dry air, N 2 , CO 2 .
• the dielectric medium is a mixture of two or three of the following: N 2 , oxygen (O 2 ), CO 2 .
• the container 130 extends along the axis A and has an axial end 135.
• a lid part 140 on the stationary-contact side is made of a conductive material and extends in the direction of the axis A (the axial direction) to reach the container 130, i.e. it extends at least up to the axial end 135 of the container 130.
• An outer circumferential surface 146 of the lid part 140 extends at a shorter radial distance r2 than an outer circumferential surface 136 of the ceramic container 130. That is, when moving along any of the outer circumferential surfaces 136, 146 on the axis towards the respective other element 130, 140, a step in the radial direction (a radial step 190) is formed.
• the radial step 190 need not necessarily be a 90° directional change, but may include slightly smoother transitions as well. At or in the vicinity of the radial step 190, a triple point is formed.
• the housing includes a positioning surface.
• a positioning surface 145 is formed as an element of the lid part 140.
• the vacuum interrupter 100 further includes a field controller 150.
• the field controller 150 has a conductive shielding part 151 and an abutment part 155.
• the field controller is formed of one piece and is made of a metal material, and has substantially a plate shape or cup shape.
• the abutment part 155 is provided at a distance from the shielding part 151.
• the abutment part 155 abuts on the positioning surface 145.
• the shielding part 151 shields the radial step 190 at least partially while being spatially separated from the axial end 135.
• the shielding part may be beneficial in alleviating the dielectric stress occurring in the triple point area, i.e. at or in the vicinity of the radial step 190.
• the positioning surface 145 is in close contact with the abutment part 155, forming a low-resistant galvanic connection between the two parts.
• the field controller 150 and specifically the shielding part 151, has substantially the same electrical potential as the lid part 140.
• the conductive shielding part 151 is formed as a bulge, and the bulge extends, or bulges, radially outward. Note that the bulge may also extend beyond the radial step 190 without physically contacting, or touching, the radial step 190.
• the shielding part 151 may be beneficial in shielding the radial step 190 area and alleviate the dielectric stress in this triple point area.
• Figs. 3 through 5 show an embodiment of a vacuum interrupter 100 according to the present disclosure.
• the stationary-contact-side field controller (a second field controller) as described above in connection with Figs. 1 and 2 has been given the reference numeral 150-2, while another field controller 151-1 on the moving-contact side (a first field controller) is provided (denoted simply as field controller 150 in Figs. 4 and 5 ).
• the field controller 150 has a shielding part 151 in the form of a bulge, and an abutment part 155.
• the positioning surface 135 on the moving-contact side coincides with the axial end 135 of the container 130.
• the abutment part 155 of the field controller 150 abuts on the axial end 135, i.e. the positioning surface 135.
• the abutment part 155 is provided at a distance from the shielding part 151.
• the abutment part 155 abuts on the positioning surface 145. In this way, the shielding part shields the radial step 190 at least partially while being spatially separated from the axial end 135.
• the vacuum interrupter 100 with both the first field controller 150-1 and the second field controller 150-2, as shown in Fig. 3 . It is also possible to provide the vacuum interrupter 100 with only one of the first field controller 150-1 or the second field controller 150-2. For example, it is conceivable to provide the vacuum interrupter 100 with only one field controller 150-1 or 150-2 at a triple point that is found to be a "weaker" one of the possible triple points, e.g. one that suffers from more disadvantageous dielectric stress when field controller 150-1, 150-2 is not provided. In an example, an experiment or a simulation is carried out on a vacuum interrupter 100 without a field controller 150-1, 150-2 to find the "weakest" triple point. Then, the vacuum interrupter 100 may be equipped with only one field controller 150-1, 150-2 according to the finding.
• Fig. 4 illustrates a top-side view of a vacuum interrupter 100 to which a ring-shaped field controller 150 is being mounted.
• the radial step 190 is formed, as described above and visible, e.g., in Fig. 2 .
• the axial end 135 of the container 130 (here, an axial end 135 surface) serves as the positioning surface for ensuring a proper positioning of the field controller 150.
• the field controller 150 in Fig. 4 is composed of two half-ring parts, one of which is shown in Fig. 6 , but this is only an example and not a limitation.
• a split pin 157 see Fig.
• the conductive shielding part 151 is formed as a bulge, and the bulge extends, or bulges, radially outward. Note that the bulge may also extend beyond the radial step 190 without physically contacting, or touching, the radial step 190.
• the abutment part 155 is provided at a distance from the shielding part 151. In the ring-type configuration of Figs. 4 through 7 , the abutment part 155 abuts on the axial end 135 functioning as the positioning surface. In contrast to the shielding part 155, the abutment part 155 has no or only a minute influence on the electric field lines in the radial step 190 area. For example, the abutment part 155 has a comparatively thin or narrow configuration compared with the shielding part 151, whereas the shielding part 151, e.g. formed as a bulge, contributes significantly to the shaping of the electric field lines in the radial step 190 area, i.e. alleviating the dielectric stress.
• configuring a vacuum interrupter 100 as described herein may create about 0.2 bar pressure margin for conducting lightning impulse tests in dry air.
• the vacuum interrupter was equipped with a field controller 150 as described herein, and in some other test configurations, the vacuum interrupter was not equipped with such a field controller. It was found that the vacuum interrupter that was equipped with the field controller 150 passed the lightning impulse tests while the vacuum interrupter without the field controller did not pass some of the tests.

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• High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)

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ID=91276878

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Citations (5)

• 2024
  • 2024-05-27 EP EP24178236.6A patent/EP4657484A1/de active Pending
• 2025
  • 2025-05-26 CN CN202510681124.9A patent/CN121034894A/zh active Pending

Patent Citations (5)

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