HIGH-VOLTAGE DEVICE AND METHOD FOR INCREASING THE DIELECTRIC STRENGTH IN THE HIGH-VOLTAGE DEVICE

Abstract

A high-voltage device has an encapsulation housing and at least one bushing for at least one conductor, through which a current flows, into the encapsulation housing and/or out of the encapsulation housing. At least one electrode at free potential is surrounded by the bushing. The at least one electrode at free potential increases the dielectric strength in the high-voltage device, especially in the region of the bushing.

Claims

1-13. (canceled)

14. A high-voltage device, comprising: an encapsulation housing; at least one bushing for guiding at least one live conductor into said encapsulation housing and/or out of said encapsulation housing; and at least one electrode at free potential enclosed by said at least one bushing.

15. The high-voltage device according to claim 14, comprising at least one switching unit of a high-voltage circuit breaker.

16. The high-voltage device according to claim 15, wherein said at least one switching unit is arranged in said encapsulation housing and/or is connected via said at least one live conductor to power consumers, power generators, and/or lines of a power grid.

17. The high-voltage device according to claim 14, wherein said at least one electrode at free potential is cylindrical in shape.

18. The high-voltage device according to claim 14, wherein said at least one electrode at free potential has a center axis that is congruent with a longitudinal axis of said at least one live conductor.

19. The high-voltage device according to claim 14, further comprising at least one electrode at ground potential in said bushing.

20. The high-voltage device according to claim 19, wherein said at least one electrode at ground potential is spaced apart from said at least one electrode at free potential and encloses, at least partially, said at least one electrode at free potential.

21. The high-voltage device according to claim 19, wherein said at least one electrode at free potential has center axis that is congruent with a center axis of said at least one electrode at ground potential, and/or wherein said at least one electrode at free potential is formed longer along the center axis than said at least one electrode at ground potential.

22. The high-voltage device according to claim 14, which further comprises an electrically insulating spacer mounting said at least one electrode at free potential on said encapsulation housing.

23. The high-voltage device according to claim 22, wherein said electrically insulating spacer is configured to mount said at least one electrode at free potential equidistant to said at least one live conductor.

24. The high-voltage device according to claim 22, wherein said electrically insulating spacer is made of a material selected from the group consisting of ceramic, plastic, silicone, polytetrafluoroethylene (PTFE), Teflon®, epoxy resin, and a composite material.

25. The high-voltage device according to claim 14, wherein said encapsulation housing comprises a flange and an insulator fastened in a mechanically stable manner on said flange.

26. The high-voltage device according to claim 25, wherein said insulator is a hollow-tubular and/or circular-cylindrical insulator formed with ribs on an outer circumference thereof.

27. The high-voltage device according to claim 25, wherein a center axis of said insulator is coaxial with a center axis of said at least one electrode at free potential and/or with a longitudinal axis of said at least one live conductor.

28. The high-voltage device according to claim 25, wherein said at least one electrode at free potential projects into said encapsulation housing and/or into said insulator.

29. The high-voltage device according to claim 14, wherein said at least one electrode at free potential consists of a metal or a metallic alloy.

30. The high-voltage device according to claim 29, wherein said metal is at least one metal selected from the group consisting of copper, aluminum, and steel.

31. The high-voltage device according to claim 14, wherein at least one of said encapsulation housing or said bushing is filled with clean air.

32. A method for increasing a dielectric strength in a high-voltage device, the method which comprises providing at least one electrode at free potential inside at least one bushing for a live conductor leading into an encapsulation housing of the high-voltage device and/or leading out of the encapsulation housing, wherein the at least one electrode is disposed to increase the dielectric strength relative to a bushing without an electrode at free potential.

33. The method according to claim 32, which comprises providing the at least one electrode at free potential in the high-voltage device according to claim 14.

Description

[0025] An exemplary embodiment of the invention is schematically shown in the single FIGURE below and described in more detail hereinafter.

[0026] There is shown.

[0027] FIGURE schematically shows a sectional view of a detail of a high-voltage device 1 according to the invention, having an opening in an encapsulation housing 2, and having a bushing 3 for a live conductor 4 through the opening, wherein an electrode 5 at free potential is comprised by the bushing 3.

[0028] FIG. 1 schematically shows a sectional view of a detail from a high-voltage device 1 according to the invention, having an opening in an encapsulation housing 2 of the high-voltage device 1. The opening comprises a flange 9, which is in the form of a ring or rim. Boreholes for fastening means, for example screws, are formed in the flange 9. A hollow-tubular insulator 10 is arranged standing perpendicularly on the flange 9, and is fastened via the fastening means, in particular screws, in a mechanically stable manner on the flange 9. The encapsulation housing 2 having flange 9 is formed, for example, from a metal, in particular aluminum. The insulator 9 is, for example, made of ceramic, silicone, and/or composite materials. In particular rim-shaped ribs for extending leakage current paths are formed on the outer circumference of the insulator 10.

[0029] The hollow-tubular insulator 10, having circular cross section, has a longitudinal axis 6 which stands perpendicularly on the opening plane of the circular opening, and intersects or penetrates the opening in the encapsulation housing 2 in the circle center point. A switching unit of a high-voltage circuit breaker, comprised by the high-voltage device 1 according to the invention, is arranged, for example, in the encapsulation housing 2 and electrically connected via conductor 4 to power consumers, power generators, and/or power lines of a power grid outside encapsulation housing 2. An electrical conductor 4, which is a live conductor 4 in operation of the high-voltage device 1 or in the closed state of the switching unit and is generally referred to below as a live conductor 4 for all switch positions or states of high-voltage devices in order to express its effect with respect to the opening and electrodes, is in particular in the form of a rod or bar, having a longitudinal axis implied by or identical with the longitudinal axis 6 of the insulator. The live conductor 4 is made, for example, of copper, aluminum, and/or conductive steel.

[0030] When current flows through the live conductor 4, there is an electrical and magnetic field around the conductor 4. The conductor 4 is at high voltage potential, in particular up to 1200 kV, and the encapsulation housing 2 is grounded, i.e., at ground potential. The potential difference between grounded encapsulation housing 2 and live conductor 4 can result in voltage flashovers and/or short-circuits. To prevent this, the opening in the encapsulation housing 2 has a sufficient radius, which ensures a minimum distance between conductor 4 and encapsulation housing 4, which is sufficiently large to prevent voltage flashovers. The required minimum distance is dependent on the insulating gas, using which the encapsulation housing 4 and the insulator 10 are filled, for example clean air, and on the pressure of the insulating gas, for example 1 bar. Further measures, such as an insulating paint on the conductor 4 and/or the interior of the encapsulation housing 4, can enable reductions of the minimum distance.

[0031] One possibility for reducing the minimum distance, with sufficient dielectric strength in the area of the opening in the encapsulation housing 4, is the use of an electrode 7 at ground potential, as shown in the FIGURE. The electrode 7 is made of a metal, in particular aluminum, copper, and/or steel, is in the form of a hollow cylinder or hollow tube, having circular cross section. The hollow-tubular electrode 7, having circular cross section, has a longitudinal or center axis 6 which stands perpendicularly on the opening plane of the circular opening and intersects or penetrates the opening in the encapsulation housing 2 in the circle center point. The longitudinal or center axis of the electrode 7 at ground potential is implied by or identical with the longitudinal axis 6 of the insulator 10. The electrode 7 is fastened in a mechanically stable and electrically conductive manner using fastening means, for example screws, on the flange 9 of the encapsulation housing 2 and protrudes into the insulator 10. The electrode 7 changes the electrical field between encapsulation housing 2 and live conductor 4 in such a way that voltage flashovers at the opening of the encapsulation housing 2 or the flange 9 are shielded by the electrode 7 or are displaced into the interior of the insulator 10.

[0032] According to the invention, a further shielding of the electrical field or change of the field between encapsulation housing 2 and live conductor 4 is possible by using an electrode 5 at free potential. The electrode 5 is made of a metal, in particular aluminum, copper, and/or steel, in the form of a hollow cylinder or hollow tube, having circular cross section. The cross section is smaller than the cross section of the electrode 7. The hollow-tubular electrode 5 having circular cross section has a longitudinal or center axis 6, which stands perpendicularly on the opening plane of the circular opening and intersects or penetrates the opening in the encapsulation housing 2 in the circle center point. The longitudinal or center axis of the electrode 5 at free potential implies or is identical with the longitudinal axis 6 of the insulator 10 and the center axis of the electrode 7 at ground potential.

[0033] The electrode 5 is fastened via a spacer 8 on the flange 9 of the encapsulation housing 2 in a mechanically stable and electrically insulated manner, and protrudes both into the insulator 10 and also into the encapsulation housing 2. The electrode 5 protrudes further into the insulator 10 than the electrode 7 and shields the electrode 7 at ground potential in relation to the live conductor 4. The spacer 8 is made of an electrically insulating material, in particular of ceramic, plastic, silicone, PTFE, Teflon, epoxy resin, and/or a composite material. The spacer fixes the electrode 5 at free potential in particular equidistantly to the live conductor 4 and to the encapsulation housing 2, i.e., to the flange 9.

[0034] The electrode 5 at free potential changes the electrical field between encapsulation housing 2 and live conductor 4 in such a way that voltage elevations at the opening of the encapsulation housing 2 or the flange 9 and at the electrode 7 at ground potential are shielded by the electrode 5 at free potential or are displaced in attenuated form further into the interior of the insulator 10 and into the encapsulation housing 2. Voltage flashovers and/or short-circuits between the encapsulation housing 2 and the live conductor 4 are thus prevented, even with reduced size of the opening of the encapsulation housing 2 or the flange 9, low insulating gas pressures, upon use of alternative insulating gases such as clean air, and/or increased voltage levels in operation of the high-voltage device 1.

[0035] Material savings and lower costs for materials with smaller sizes and wall thicknesses of encapsulation housings 2 and insulators 10 are linked thereto, lower weight with increased dielectric strength in the area of the bushing 3 of the live conductor 4 through the opening in the encapsulation housing 2, and the use of alternative switching gases is possible, such as clean air, at low pressures, for example, 1 bar. The reliability and service life of the high-voltage device 1 are increased and maintenance expenditure is reduced.

[0036] The above-described exemplary embodiments can be combined with one another and/or can be combined with the prior art. Thus, for example, high-voltage devices 1 can comprise high-voltage circuit breakers, isolators, transformers, arrestors, measurement transducers, and/or bushings. High-voltage devices, in particular circuit breakers, are, for example, designed as gas-insulated circuit breakers, i.e., gas-insulated switch gears. The basic principle, having an electrode at free potential in a bushing of conductors through openings at ground potential, is also usable in open air circuit breakers or open air high-voltage devices. The invention is usable in dead tank facilities, i.e., with a switching unit arranged in a grounded housing. However, the basic principles are also usable in live tank facilities, i.e., with a switching unit at high voltage potential arranged in an insulator. The electrode 5 at free potential is made, for example, hollow cylindrical. Further shapes, for example having elliptical cross section and/or formed as a truncated cone, are also possible.

[0037] The encapsulation housing 2 of the high-voltage device is, for example, in the form of a vessel, and is closed gas-tight via the insulators 10. Vessels are, for example, spherical or cylindrical, further shapes are also possible. Connections between elements of the high-voltage device are carried out, for example, in a mechanically stable manner via fastening means, in particular screws, and at least one flange. Further or alternative connection technologies, in particular adhesive bonds, welded bonds, and/or soldered bonds, are also applicable. The use of seals for the gas-tight connection of elements, in particular copper seals, is possible. The spacer is, for example, disc-shaped in one piece. Alternatively, multipart spacers having identical or different partial shapes are usable. Electrode ends are rounded, for example, to avoid field elevations. Further shapes of the electrode ends, for example extending linearly, angled, rounded having different rounding radii, are possible.

LIST OF REFERENCE NUMERALS

[0038] 1 high-voltage device [0039] 2 encapsulation housing [0040] 3 bushing [0041] 4 live conductor [0042] 5 electrode at free potential [0043] 6 longitudinal or center axis [0044] 7 electrode at ground potential [0045] 8 spacer [0046] 9 flange [0047] 10 insulator