Patent Application
20210313109
The invention relates to an arrangement and a method for the gradual shutoff of potential in high-voltage technology, comprising at least one fitting body, electrically insulating film, and electrically conductive regions, wherein the electrically conductive regions are arranged between layers of the electrically insulating film, and at least parts of the electrically insulating film are arranged around the at least one fitting body.
In high-voltage technology, parts of outdoor installations that carry high voltage are electrically insulated from the ground potential by porcelain and/or composite insulators. In order to ensure the required dielectric strength of the insulating clearance, the potential between high voltage and ground potential is gradually shut off as homogeneously as possible, i.e. a uniform potential distribution is produced along the insulator. The gradual shutoff is effected by means of a control electrode at low voltage levels, a larger insulator diameter and/or larger designs additionally being required at higher voltage levels, associated with significantly higher use of material. This applies to AC applications, i.e. alternating-current voltage applications, and to DC applications, i.e. direct-current voltage applications, in particular in the high-voltage range of up to 550 kV and/or of up to 1200 kV. In the case of DC applications, the resistive potential distribution established is a determining factor here.
EP 0 600 233 A1 discloses a gradual shutoff which is effected by means of a few electrodes mechanically coupled to one another by insulating pieces. This electrode arrangement enables a coarsely controlled gradual shutoff.
Alternatively, a gradual shutoff of potential can be effected by means of an RIP, i.e. a resin impregnated paper, control. In that case, a multiplicity of aluminum coatings separated from one another by paper layers are wound cylindrically onto a former and impregnated with casting resin, thus giving rise to a solid resin cylinder. The resin cylinder, comprising aluminum coatings electrically insulated from one another by paper layers, forms the electrode arrangement.
In the case of DC applications, in contrast to AC applications, the potential distribution is determined by the resistive current established in the steady state. In the case of AC applications, by contrast, the potential distribution is determined by the capacitive distribution. Thus, with an identical arrangement, it is possible for different potential distributions and field loads to arise in the case of AC and DC loads.
It is an object of the present invention to specify an arrangement and a method for the gradual shutoff of potential in high-voltage technology which are suitable for AC and DC applications. In particular, it is an object to specify an arrangement for the gradual shutoff of potential which is suitable for AC applications and which is suitable in the same form for DC applications.
The object specified is achieved according to the invention by means of an arrangement for the gradual shutoff of potential in high-voltage technology having the features as claimed in patent claim 1 and/or by means of a method for the gradual shutoff of potential in high-voltage technology, in particular using the arrangement described above, as claimed in patent claim 13. Advantageous configurations of the arrangement according to the invention for the gradual shutoff of potential in high-voltage technology and/or of the method for the gradual shutoff of potential in high-voltage technology, in particular using the arrangement described above, are specified in the dependent claims. In this case, subjects of the main claims are combinable among one another and with features of dependent claims, and features of the dependent claims are combinable among one another.
An arrangement according to the invention for the gradual shutoff of potential in high-voltage technology comprises at least one fitting body, electrically insulating film, and electrically conductive regions, wherein the electrically conductive regions are arranged between layers of the electrically insulating film. At least parts of the electrically insulating film are arranged around the at least one fitting body. The arrangement is configured for direct-current applications.
The requirements in respect of direct-current DC applications are higher than the requirements in respect of alternating-current AC applications. However, e.g. AC arrangements used as standard for the gradual shutoff of potential for a current/voltage level can be used as DC arrangements of a lower current/voltage level, in particular as arrangements for exactly one current/voltage level lower. As a result, development costs can be saved and production costs can be lowered by way of higher numbers produced.
The electrically conductive regions between layers of the electrically insulating film can be configured as gradual potential shutoff coatings. At least one fitting body can be configured as a first gradual potential shutoff coating. By using the fitting body as a first gradual potential shutoff coating, it is possible to save one gradual shutoff coating and to simplify the production of the arrangement. An electrical contacting of the fitting body is possible simply, stably and cost-effectively e.g. by way of an eye.
The arrangement can be configured in a rotationally symmetrical fashion, in particular in a circular-cylindrical fashion, with the at least one fitting body, in particular in the manner of a winding tube, arranged at a first end in the interior, and with a cylindrical cladding tube, in particular a slotted cladding tube, arranged at a second end on the exterior. The winding of the electrically insulating film with electrically conductive regions between layers of the electrically insulating film is possible in a simple manner in the case of rotationally symmetrical arrangements, without e.g. breaks at edges and/or corners.
The electrically insulating film can be wound at least partially around the at least one fitting body, with electrically conductive regions electrically insulated from one another by way of the film, wherein at least one electrical contact making contact with an electrically conductive region can be formed by way of an opening in an in particular outer layer of the film. Forming the at least one electrical contact making contact with an electrically conductive region by way of the opening in a layer of the film enables a simple, stable and cost-effective electrical contacting.
The at least one electrical contact can be formed by an electrically conductive film strip, in particular an aluminum film strip, which is led through the opening. This enables a simple, stable and cost-effective electrical contacting, without the risk of a contact breaking as a result of bending. In the prior art the contact is usually produced by way of the outer edge of a film layer, the contact being bent at the edge. This can result in breaks in the contact, in particular on account of the small thickness of the films.
A plurality of electrical contacts, in particular three, making contact with an electrically conductive region can be formed by way of openings in the outer layer of the film, in particular by way of three openings arranged offset respectively by 120 degrees relative to one another on a circumferential radius. This provides a good electrical contact, with a favorable field distribution.
The at least one electrical contact can be clamped between the electrically conductive region located furthest outward in a radial direction and the outer layer of the film with one opening, and/or can be led flat through the opening, and/or can be clamped between the outer layer of the film and the cladding tube, in particular can be led toward the outside by way of a respective slot in the cladding tube. In terms of production, clamping is simple to realize and inexpensive and this results in a contact having good electrical conductivity and mechanical stability in conjunction with close winding of the film.
The at least one electrical contact can be formed in the shape of a ribbon, and/or can be folded away on the exterior at an angle of substantially 45 degrees along the outer circumference of the cylindrical cladding tube, in particular can be arranged with a longitudinal direction running along a circular circumference of the cladding tube. An electrical contact formed in the shape of a ribbon can be clamped between a film in a simple manner, is mechanically stable without easily breaking and yields a large area for a good electrical conduction. Folding away at an angle of substantially 45 degrees enables external electrical contacting simply and cost-effectively, wherein a direction change in the longitudinal direction of the contact formed in the shape of a ribbon is produced by the folding away.
The film can comprise an electrically insulating polymer and/or paper, in particular impregnated with resin. This produces a good electrical insulation by way of the film. The fitting body and/or the cladding tube can be composed of an electrically conductive material, in particular metal, in particular copper, aluminum and/or steel. This enables a good electrical contact of the arrangement by way of the fitting body and/or the cladding tube.
The fitting body can comprise at least one electrical contact connection, in particular in the form of a socket, for connecting a ground potential.
The electrically conductive regions can be formed between layers of the electrically insulating film from a metallic coating of the film or an inserted metallic film, in particular with each conductive region having substantially the shape of a lateral surface of a cylinder between adjacent layers of the electrically insulating film, in particular in each case spatially offset relative to one another along the longitudinal axis of the arrangement. A metallic coating of the film or an inserted metallic film is able to be wound with the film in a simple manner and is cost-effective.
The arrangement can have for direct-current applications for a direct-current high voltage spatially the dimensions which are configured for an alternating-current high voltage of a higher level, in particular with dimensions for alternating-current high voltage exactly one alternating-current high voltage level higher. As a result, arrangements can be produced and used in greater numbers, without being separately developed and produced in small numbers for direct-current high voltages.
A method according to the invention for the homogeneous gradual shutoff of high-voltage potentials along at least one insulator using an arrangement described above comprises the fact that resistive compensation currents along the electrically insulating film are reduced and/or avoided, by means of design for higher voltage levels, and/or by means of a fitting body acting as a first gradual potential shutoff coating, and/or by means of the electrical contacting of the outermost electrically conductive region between layers of electrically insulating film by way of an electrical contact through an opening in the outer layer of the insulating film.
The advantages of the method according to the invention for the homogeneous gradual shutoff of high-voltage potentials along at least one insulator using an arrangement described above as claimed in claim 13 are analogous to the above-described advantages of the arrangement according to the invention for the gradual shutoff of potential in high-voltage technology as claimed in claim 1, and vice versa.
Hereinafter an exemplary embodiment of the invention is illustrated schematically in
In the figures in this case:
The arrangement 27 according to the invention comprises an insulating body 3 composed of e.g. layers of an electrically insulating film wound around the conductive pin 5, said film comprising electrically conductive regions 4 between the layers. The electrically conductive regions 4 are configured as gradual potential shutoff coatings and are arranged e.g. offset relative to one another, along the longitudinal axis of the arrangement 27, in an overlapping manner between the layers of the insulating film. The electrically conductive regions 4 are formed e.g. as a metallic coating of the electrically insulating film or in each case as an inserted metallic film between layers of the insulating film. In this case, the electrically conductive regions 4 e.g. consist of and/or comprise an electrically conductive material, in particular a metal, e.g. copper, aluminum and/or steel. The electrically insulating film consists of and/or comprises paper, in particular a resin impregnated paper. Alternatively or additionally, electrically insulating polymers can be used as electrically insulating film.
The bushing 1 can be used e.g. for connecting transformers situated in a housing. Centrally along the longitudinal axis of the bushing 1, in the region in which the bushing 1 is led through the wall of the transformer housing, a flange 6 is arranged around the circumference of the arrangement 27 according to the invention. The flange 6 comprises e.g. a measurement connection 7 and an outlet valve 8, and seals off the inner region of the transformer housing, said inner region being filled with oil, for example, from the outer region, e.g. a gas or air region. One end of the bushing 1 comprises the gas-side connection 2 outside the transformer housing and the opposite end comprises the transformer-side connection 9. At the end of the transformer-side connection 9, an electrode 10 is arranged around the connection 9 in a ring-shaped manner.
In the exemplary embodiment in
The pressure vessel 16 of the high-voltage measuring transducer 11 is arranged on the support insulator 15, which is embodied in a column-shaped fashion and is arranged upright, on a carrier 17. The carrier 17 comprises e.g. intersecting steel beams and is secured on a foundation, which is not illustrated in the figures for the sake of simplicity. The column-shaped support insulator 15 is secured by one end on the carrier 17, said end being sealed in a gastight fashion. At that end the terminal box 23 is secured to the column-shaped support insulator 15, and devices such as e.g. a filling connection 19, a test connection 20 and/or a sealtightness monitor 21 are arranged at that end.
The support insulator 15 and the pressure vessel 16 are filled e.g. with SF6 and/or clean air as insulating gas 14 and are sealed in a gastight manner as a housing 12. Filling can be effected via the filling connection 19, and the sealtightness and the gas pressure in the interior can be checked via the test connection 20 and the sealtightness monitor 21. At the upper end of the column-shaped support insulator 15, the pressure vessel 16 is formed in the shape of a pot, arranged on the support insulator 15, with a bursting disk as overpressure device 18 at the upper end of the pressure vessel 16. In the event of a great increase in pressure of the insulating gas 14 in the housing 12, e.g. caused by heating by way of environmental influences, in particular insolation, by way of malfunctions or evolution of heat caused by large currents, an overpressure can be relieved upward out of the housing 12 by means of bursting of the bursting disk. This prevents e.g. an explosion of the support insulator 15 and/or of the pressure vessel 16, in the event of which flying pieces of debris could injure persons in the surroundings.
The pressure vessel 16 is formed e.g. from steel, cast iron and/or aluminum, with a wall thickness that withstands an insulating gas pressure of e.g. 6 to 15 bar with long-term stability. The wall thickness is e.g. in the range of from millimeters to centimeters. The column-shaped support insulator 15 is hollow in the interior, formed with a wall thickness that likewise withstands the insulating gas pressure of e.g. 6 to 15 bar with long-term stability and supports the weight of the pressure vessel 16 with the connection loads secured thereto. The support insulator 15 is composed e.g. of ceramic, silicone and/or of a composite material. The outer circumference of the support insulator 15 has ring-shaped slats extending around the outer circumference, arranged at regular intervals along the longitudinal axis of the column-shaped support insulator 15. As a result, the creepage current path along the longitudinal axis of the column-shaped support insulator 15 is lengthened, and the external insulation effect of the support insulator 15 is improved.
In the interior of the column-shaped support insulator 15, a dissipating tube 26 for grounding the measuring device 13 is arranged along the longitudinal axis and a control electrode 25 is arranged rotationally symmetrically around the dissipating tube 26 in the upper region of the support insulator 15, in order to improve the field distribution in that region. The control electrode 25 and/or the dissipating tube 26 are/is formed in particular from metals having good electrical conductivity, such as e.g. copper and/or steel.
The arrangement 27 according to the invention for the gradual shutoff of potential is arranged in particular rotationally symmetrically around the dissipating tube 26. The arrangement 27 according to the invention extends along the longitudinal axis of the dissipating tube 26 and envelops the circumference of the dissipating tube 26. The arrangement 27 according to the invention extends from the pressurized gas vessel 16 into the support insulator 15 along the center axis of the support insulator 15. A gradual shutoff of potential from the high-voltage potential of the current conductor to ground potential in the region of the terminal box 23 is effected by means of the arrangement 27 according to the invention.
The inventive arrangement 27 is electrically contacted via the fitting body 28 and the cladding tube 32, and the potential is gradually shut off between the two ends of the arrangement 27 by way of the electrically conductive regions or control coatings 4 wound or arranged offset between the layers of insulating film 29.
The electrical contact 30, in particular in the form of the conductor strip or flat conductor ribbon, is led e.g. via continuous slots in the cladding tube 32 to the outer circumference of the inventive arrangement 27 and can be contacted toward the outside e.g. by clamping, soldering and/or screwing e.g. with electrical lines, in particular with high electrical potential. A plurality of slot arrangements, in particular three, arranged offset by in each case 120 degrees relative to one another along the outer circumference of the cladding tube 32, with respective openings 31 arranged in that region in the outer layer of the insulating film 29, can be formed in the arrangement 27 according to the invention. As a result, in each case by way of a slot arrangement and a conductor strip 30 led outward through the respective opening 31 and slot arrangement, the outer electrically conductive region 4 can be electrically contacted, i.e. the region 4 located furthest outward along the radius perpendicular to the longitudinal axis of the circular cross section of the arrangement 27. With three slot arrangements, assigned openings and conductor strips, it is possible to produce a good, stable electrical contact between the outer electrically conductive region 4 and e.g. electrical lines on the outer circumference of the inventive arrangement 27.
As is illustrated in
The exemplary embodiments described above can be combined among one another and/or can be combined with the prior art. In this regard, e.g. more or fewer than three slot arrangements arranged offset by 120 degrees, with respective openings 31 arranged in that region in the outer layer of the insulating film 29, can be formed in the arrangement 27 according to the invention. By way of example, one opening 31 and/or slot arrangement can be formed, or e.g. two openings 31 and/or slot arrangements situated radially opposite one another along the circular circumference of the arrangement 27 can be formed. The arrangement can also comprise four openings 31 and/or slot arrangements arranged offset in each case by 90 degrees relative to one another along the circular circumference. Instead of slot arrangements, openings e.g. of rectangular or square shape can also be provided in the cladding tube 32, a conductive strip 30 being led through said openings.
Conductive strips 30 can be led along the outer electrically conductive region 4, in a manner clamped by the outer layer of insulating film 29, along the longitudinal axis of the arrangement 27 according to the invention, can be led outward through the opening 30 in a manner folded by 45 degrees in a direction perpendicular to the longitudinal axis in the region of the opening and can be clamped by the cladding tube 32 and be led outward through a slot arrangement in the cladding tube 32 in a direction perpendicular to the longitudinal axis. Alternatively or additionally, as is shown e.g. in
Resistive compensation currents along the electrically insulating film 29 are avoided by means of the arrangement 27 according to the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2018 215 274.8 | Sep 2018 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/071291 | 8/8/2019 | WO | 00 |
