Potential transformers

Abstract

The present invention relates to a potential transformer (1). The potential transformer (1) has at least one primary winding (5), an electrode (7) for the primary winding (5) electrically connected to one end of the primary winding (5), and an electrical bushing contact (11) spaced from the primary winding (5). The potential transformer (1) further has a support element (13) rotatable about a rotation axis (35) between a first end position and a second end position, and an electrically conductive contact component (15) arranged on the support element (13) for each primary winding (5), the contact component (15) electrically connecting the electrode (7) of the primary winding (5) to the bushing contact (11) in the first end position of the support element (13) and electrically isolating it from the bushing contact (11) in the second end position of the support element. The contact component (15) has at least one rolling contact (43, 45, 75), and in a first end position of the support element (13), the contact component (15) contacts the electrode (7) of the primary winding (5) or the bushing contact (11) via the rolling contact.

Description

[Technical field]

[0001] The present invention relates to a potential transformer.

[0002] The invention relates in particular to potential transformers for high-voltage switchgear. By means of such potential transformers, high voltages are converted proportionally and with correct phase accuracy into lower values ​​for measurement, protection or control purposes. For this purpose, potential transformers of the induction type generally have at least one magnet core, around which a primary winding and at least one secondary winding are wound. In special operating conditions of the switchgear, for example for certain commissioning tests, it is necessary to isolate the potential transformer from the rest of the switchgear, since otherwise the potential transformer could be damaged or destroyed. For this purpose, the potential transformer may, for example, have an isolation device, which allows to separate the electrical connection between the potential transformer and the rest of the switchgear. Summary of the Invention [Problem to be solved by the invention]

[0003] SUMMARY OF THE DISCLOSURE It is an object of the present invention to provide a potential transformer having improved electrical insulation from the switchgear. [Means for solving the problem]

[0004] This problem is solved according to the invention by a potential transformer having the features of claim 1.

[0005] Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0006] The potential transformer according to the present invention comprises: at least one primary winding; For each primary winding, there is one electrode electrically connected to one end of the primary winding and one electrically spaced apart from the primary winding. Feedthrough Contact points and a support element rotatable about an axis of rotation between a first end position and a second end position; One conductive contact component arranged on the support element for each primary winding, the contact component being connected to the primary winding and its corresponding Feedthrough A contact component is associated with the electrode of the primary winding at a first end position of the support element. Feedthrough electrically connected to the contact and at the second end position of the support element Feedthrough contact point a contact component electrically insulating the contact from the Equipped with The contact component has at least one rolling contact, and in a first end position of the support element, the contact component is coupled via the rolling contact to an electrode of the primary winding or Feedthrough Touch the contact point.

[0007] The potential transformer according to the invention provides a primary winding of the potential transformer and an associated Feedthrough At least one current path between the contacts can be opened or closed by rotating the support element, on which one contact component is arranged for each of these current paths, which current paths are closed by the contact components in a first end position of the support element and are opened in a second end position of the support element, which contact components are connected by rolling contacts to electrodes and / or electrodes electrically connected to one end of the primary winding in the first end position. Feedthrough This advantageously allows the contact components to be connected to the electrodes and / or Feedthrough Friction between the contacts, e.g., the contact components and the electrodes and / or Feedthrough The friction between the contacts is reduced compared to sliding contacts (rolling friction instead of sliding friction). Because of the lower friction, wear on rolling contacts is reduced compared to, for example, sliding contacts.

[0008] In one embodiment of the invention, each contact component has a first rolling contact and a second rolling contact, the first rolling contact contacting an electrode of a primary winding associated with this contact component in a first end position of the support element, and the second rolling contact contacting an electrode of a primary winding associated with this contact component in the first end position of the support element. Feedthrough Touch the contact point.

[0009] In other words, in the above-described embodiment of the invention, each contact component has two rolling contacts, one of which in a first end position contacts an electrode of the primary winding and the other Feedthrough contacts the contacts, and in the second end position, each of its electrodes and Feedthrough In this way, each contact component is advantageously connected to an electrode of the primary winding and its associated therewith by means of a low-friction rolling contact. Feedthrough The electrical connection between the electrode and the contact is Feedthrough Both contact sides close and open.

[0010] In a further embodiment of the invention, at least one rolling contact has a roller bearing with an electrically conductive outer ring, which in a first end position of the support element is connected to an electrode of a primary winding associated with this contact component or to an electrode of a primary winding associated with this contact component. Feedthrough That is, in this embodiment of the invention, the electrodes of the primary winding or Feedthrough The electrical connection of the rolling contacts to the contacts is made through the outer ring of the roller bearing.

[0011] In a further development of the above-mentioned embodiment of the invention, each rolling contact with a roller bearing has an electrically conductive retaining part in which the roller bearing is arranged and which is electrically connected to an outer ring of the roller bearing by means of a sliding contact. The electrical connection between the outer ring and the retaining part via the sliding contact advantageously avoids the risk of welding between the outer ring and the retaining part due to arcing through the gap between the outer ring and the retaining part caused, for example, by high currents due to fast transients.

[0012] In a further embodiment of the invention, at least one rolling contact has an electrically conductive ball supported in an electrically conductive plain bearing, the electrically conductive ball being connected in a first end position of the support element to an electrode of the primary winding associated with the contact component or to an electrode of the primary winding associated with the contact component. Feedthrough Contacting the contacts, i.e., in this embodiment of the invention, to the electrodes of the primary winding or Feedthrough The electrical connection of the rolling contacts to the contacts is made by balls which are supported in plain bearings.

[0013] In a further embodiment of the invention, each rolling contact of a contact component is resiliently supported on a base body of the contact component, whereby the electrodes of the primary winding or Feedthrough The position of the rolling contact on the contact component and the contact pressure of the rolling contact are measured by the electrodes or Feedthrough It can be flexibly adapted to the contact surface.

[0014] In a further embodiment of the invention, each rolling contact of the contact component is elastically supported on the base body of the contact component by at least one leaf spring element. Furthermore, each leaf spring element can electrically connect the rolling contact elastically supported by it to the base body of the contact component. The elastic support of the rolling contacts by leaf spring elements and the electrical connection of the rolling contacts to the base body of the contact component has the advantage that the inductance of the leaf spring elements is small compared to the use of, for example, helical springs.

[0015] In a further development of the aforementioned embodiment of the invention, each rolling contact is resiliently supported in an opening in the base body of the contact component. Furthermore, each opening in the base body of the contact component, in which a rolling contact is resiliently supported, can be surrounded by a wall of the base body having a convex outer surface. By supporting the rolling contact in an opening in the base body of the contact component, this rolling contact can be advantageously protected. By making an opening through a peripheral wall having a suitable convex outer surface surrounding the opening, an electrical shielding of the rolling contact is further advantageously obtained.

[0016] In further embodiments of the invention, the potential transformer has three primary windings, which are arranged at a distance from one another around the axis of rotation of the support element. In particular, the primary windings can be arranged at an offset of 120° from one another around the axis of rotation of the support element, which can furthermore be rotated around the axis of rotation by 60° between two end positions. These aspects of the invention allow the design of a potential transformer that is particularly suitable for three-phase AC voltages.

[0017] In a further embodiment of the invention, the support element has a support plate and a support shaft connected to the support plate, on which the contact components are arranged and through which the axis of rotation passes. The support plate may, for example, define a first spatial region in which the primary windings are arranged and a second spatial region in which the contact components are arranged. Feedthrough The support element is arranged in a plane between the first spatial region and the second spatial region in which the contacts are arranged. These configurations of the invention make it possible to realize a geometrically simple and expedient design and arrangement of the support element.

[0018] In a further embodiment of the invention, each Feedthrough The contacts have convex contact surfaces which are contacted by one rolling contact at a first end position of the support element. Feedthrough A smooth connection and disconnection of the contacts with the rolling contacts is possible.

[0019] In a further embodiment of the present invention, the potential transformer has a capsule housing, in which each primary winding, each Feedthrough The contacts, the support element and the contact components are arranged in a capsule housing, which advantageously protects the components of the potential transformer from adverse conditions such as moisture in the potential transformer's surroundings. Furthermore, the capsule housing can be made gas-tight if necessary, in order to fill it with insulating gas.

[0020] The above-mentioned characteristics, features and advantages of the present invention, as well as the manner in which they are achieved, will be more clearly and easily explained with reference to the following several embodiments taken in conjunction with the drawings. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view of a first embodiment of an instrument transformer; [Diagram 2] A perspective view of a portion of the contact components of the potential transformer shown in Figure 1. [Diagram 3] Cross-sectional view of the contact components of the potential transformer shown in Figure 1 [Figure 4] A perspective view of the contact component shown in FIG. [Diagram 5] FIG. 2 is a schematic diagram of a rolling contact in a second embodiment of an instrument transformer. In these drawings, the same parts are provided with the same reference numerals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] FIG. 1 (FIG1) is a perspective view of a first embodiment of a potential transformer 1. The potential transformer 1 includes one capsule housing 3, three primary windings 5, three secondary windings, three electrodes 7, three magnet cores 9, and three Feedthrough It comprises a contact 11, a support element 13 and three electrically conductive contact components 15. The potential transformer 1 is designed for three-phase AC voltage.

[0023] The capsule housing 3 is shown in a cutaway view and comprises a housing shell 17, a housing cover 19 and a bushing 21. The housing shell 17 is closed at the top by the housing cover 19 and at the bottom by the bushing 21. The bushing side of the housing shell 17 has a flange 23 on which the bushing 21 is arranged. The housing shell 17 is connected to the housing cover 19 and the bushing 21 by screw connections 25, 27, respectively. The secondary winding, the primary winding 5, the electrodes 7, the magnet core 9, Feedthrough The contacts 11 , the contact components 15 and the support element 13 are arranged in the capsule housing 3 .

[0024] These Feedthrough The contacts 11 are disposed on the bushings 21 and can be electrically connected to the outside through the bushings 21, so that Feedthrough The contacts 11 can be connected, for example, to an electric cable of a switchgear. Feedthrough The contact 11 has a convex contact surface 29 facing towards the housing cover 19 .

[0025] The support element 13 comprises a support shaft 31 and a support plate 33 arranged on the support shaft 31. Between a first end position and a second end position, the support element 13 can be rotated by 60° about a rotation axis 35 coinciding with the longitudinal axis of the support shaft 31.

[0026] The housing shell 17 is essentially rotationally symmetrical about a rotation axis 35 passing through approximately the centers of the housing cover 19 and the bushing 21 .

[0027] Each magnet core 9 has one leg around which one of the secondary windings and one of the primary windings 5 ​​are wound. In this case, the secondary windings are not visible in FIG. 1, since the primary winding 5 is wound around the secondary windings. The legs of the magnet cores 9 surrounded by these secondary windings and the primary windings 5 ​​are arranged in a star shape around the axis of rotation 35 in a plane perpendicular to the axis of rotation 35, offset from each other by 120°. One end of each primary winding 5 is connected to an electrode 7, which is arranged around the center of the primary winding 5.

[0028] The support plate 33 of the support element 13 defines a first spatial region in which the primary windings 5 ​​are arranged and a plurality of Feedthrough The contacts 11 are disposed in a plane between the first and second spatial regions.

[0029] A number of contact components 15 are arranged on the support plate 33. Each contact component 15 is provided with one primary winding 5 and one Feedthrough The contacts 11 are associated with a contact component 15 which are electrically connected to one another in a first end position of the support element 13 and electrically separated from one another in a second end position of the support element 13. The contact component 15 of the potential transformer 1 shown in Figure 1 will be explained in more detail with the aid of Figures 2 to 4.

[0030] A mechanism 37 for rotating the support element 13 and a junction box 39 for the potential transformer 1 are arranged in the housing cover 19. This mechanism 37 comprises a lever 41, by means of which the support element 13 can be manually rotated between its two end positions.

[0031] FIG. 2 (FIG. 2) is a perspective view of a portion of the contact component 15 of the potential transformer 1 shown in FIG.

[0032] Figure 3 (FIG3) and Figure 4 (FIG4) show the contact component 15 of the potential transformer 1 shown in Figure 1. Figure 3 is a cross-sectional view of the contact component 15, and Figure 4 is a perspective view of the contact component 15.

[0033] This contact component 15 comprises two rolling contacts 43, 45. Each rolling contact 43, 45 has one roller bearing 47 with an electrically conductive outer ring 49. In a first end position of the support element 13, the outer ring 49 of the first rolling contact 43 contacts the electrode 7 of the primary winding 5 associated with this contact component 15. In a first end position of the support element 13, the outer ring 49 of the second rolling contact 45 contacts the electrode 7 of the primary winding 5 associated with this contact component 15. Feedthrough The rolling contacts 43, 45 contact the contact surface 29 of the contact 11. Furthermore, each rolling contact 43, 45 has an electrically conductive holding part 51, inside which the roller bearing 47 is arranged and which is electrically connected to the outer ring 49 of the roller bearing 47 by means of a sliding contact 53. The sliding contact 53 is configured as a spring contact, which is fixed to the holding part 51 by means of a screw connection 55 and rests under pressure against the outer ring 49.

[0034] Each rolling contact 43, 45 is elastically supported by a leaf spring element 57 in an opening 59 in an electrically conductive base body 61 of the contact component 15. The leaf spring element 57 also electrically connects the holder 51 of the roller bearing 47 to the base body 61. In this case, the rolling contacts 43, 45 are guided in the openings 59 by a guide 63, the leaf spring element 57 extending outside the guide 63 from an open bottom 65 of the opening 59 to the holder 51 of the roller bearing 47. The guide 63 is fixed to the base body 61 by a screw connection 67.

[0035] The openings 59 in the base body 61 of the contact components 15 are each surrounded by a wall 69 of the base body 61 having a convex outer surface 71. The contact components 15 are fixed to the support plate 33 by a threaded connection 73.

[0036] FIG. 5 (FIG. 5) shows a schematic representation of the rolling contacts 75 of the contact components 15 of a second embodiment of the potential transformer 1. The rolling contacts 75 have conductive balls 79 supported in conductive sliding bearings 77, which are shown in cross-section here. The second embodiment is identical to the first embodiment of the potential transformer 1 shown in FIGS. 1 to 4, except for the design of the rolling contacts 75. That is, each contact component 15 of the second embodiment has two rolling contacts 75, which are each elastically supported inside an opening 59 in the base body 61 of the contact component 15, similar to the rolling contacts 43, 45 of the embodiment shown in FIGS. 1 to 4.

[0037] Although the present invention has been shown and described in detail by means of preferred embodiments, the present invention is not limited to the disclosed embodiments, and other modifications can be derived therefrom by those skilled in the art without departing from the scope of protection of the present invention. In other embodiments, the potential transformer 1 can, for example, have an arrangement along three sides of an equilateral triangle instead of a star-shaped arrangement of the magnet cores 9, or can have other than three magnet cores and / or primary windings 5.

Claims

1. At least one primary winding (5); One electrode (7) electrically connected to one end of the primary winding (5) provided corresponding to each of the primary windings (5), and one electrical feed-through contact (11) spaced apart from the primary winding (5); a support element (13) rotatable about an axis of rotation (35) between a first end position and a second end position; one electrically conductive contact component (15) arranged on the support element (13) for each of the primary windings (5), the contact component (15) being associated with the primary winding (5) and the corresponding feed-through contact (11), the contact component (15) electrically connecting the electrode (7) of the primary winding (5) to the feed-through contact (11) at a first end position of the support element (13) and electrically isolating the electrode (7) of the primary winding (5) from the feed-through contact (11) at a second end position of the support element; A potential transformer (1) having Each of said contact components (15) has a first rolling contact (43) and a second rolling contact (45); said first rolling contact (43) contacts an electrode (7) of a primary winding (5) associated with said contact component (15) in a first end position of said support element (13); said second rolling contact (45) contacts said feed-through contact (11) associated with said contact component (15) in a first end position of said support element (13); The rolling contacts (43, 45) have roller bearings (47) with conductive outer rings (49); the outer ring (49) of the first rolling contact (43) contacts the electrode (7) of the primary winding (5) associated with the contact component (15) in the first end position of the support element (13), the outer ring (49) of the second rolling contact (45) contacts the feed-through contact (11) associated with the contact component (15) at the first end position of the support element (13), A potential transformer (1).

2. A first axial direction in which the first rolling contact (43) applies a contact pressure to the electrode (7) of the primary winding (5) associated with the contact component (15) is different from a second axial direction in which the second rolling contact (45) applies a contact pressure to the feed-through contact (11) associated with the contact component (15), A potential transformer (1) according to claim 1.

3. Each of the rolling contacts (43, 45) having the roller bearing (47) has an electrically conductive retaining portion (51); The roller bearing (47) is disposed in the retaining portion (51), the retaining portion (51) is electrically connected to the outer ring (49) of the roller bearing (47) by a sliding contact (53); A potential transformer (1) according to claim 2.

4. A first axial direction in which the first rolling contact (43) applies a contact pressure to the electrode (7) of the primary winding (5) associated with the contact component (15) is different from the direction of the rotation axis (35) of the support element (13), A potential transformer (1) according to any one of claims 1 to 3.

5. 5. The potential transformer (1) according to claim 1, wherein each rolling contact (43, 45) of the contact component (15) is elastically supported on a base body (61) of the contact component (15).

6. 6. The potential transformer (1) according to any one of claims 1 to 5, characterized in that each of the rolling contacts (43, 45) of the contact component (15) is elastically supported on a base body (61) of the contact component (15) by at least one leaf spring element (57).

7. 7. The potential transformer (1) according to claim 6, characterized in that each said leaf spring element (57) electrically connects the rolling contacts (43, 45) elastically supported by said leaf spring element (57) to the base body (61) of the contact component (15).

8. 8. The potential transformer (1) according to any one of claims 5 to 7, characterized in that each of the rolling contacts (43, 45) is elastically supported in an opening (59) in a base body (61) of the contact component (15).

9. It has three primary windings (5), 9. The potential transformer (1) according to any one of claims 1 to 8, characterized in that the three primary windings (5) are arranged spaced apart from one another around the rotation axis (35) of the support element (13).

10. the primary windings (5) are arranged offset from one another by 120° around the axis of rotation (35) of the support element (13); said support element (13) can rotate about said axis of rotation (35) by 60° between said two end positions; A potential transformer (1) according to claim 9.

11. The support element (13) has a support plate (33) and a support shaft (31) connected to the support plate (33), Each of the contact components (15) is arranged on the support plate (31); The support shaft (31) is connected to the support plate (33), and the rotation axis (35) passes through the support shaft (31). A potential transformer (1) according to any one of claims 1 to 10.

12. 12. The potential transformer (1) according to claim 11, characterized in that the support plate (33) is arranged in a plane between a first spatial area in which each of the primary windings (5) is arranged and a second spatial area in which each of the feed-through contacts (11) is arranged.

13. Each of said feed-through contacts (11) has a convex contact surface (29); said contact surface (29) is contacted by one rolling contact (43, 45) at said first end position of said support element (13); A potential transformer (1) according to any one of the preceding claims.

14. A capsule housing (3), The primary windings (5), the feed-through contacts (11), the support elements (13) and the contact components (15) are arranged inside the capsule housing (3). A potential transformer (1) according to any one of the preceding claims.

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