EP1958217B1 - Electrical winding and manufacturing method therefor - Google Patents

Abstract

An electrical winding contains a metallic winding conductor forming individual windings. The metallic winding conductor contains a metallic conductor and an electrically insulating material surrounding the metallic conductor. An insulation inside the electrical winding can be ensured in a targeted manner by combining an electrically insulating material with a metal oxide layer surrounding the metallic winding conductor, according to the maximum electric strength required inside the electrical winding. In this way, a reduced-size electrical winding can be produced with improved heat properties. An electrical insulation of a metallic electric conductor is further described.

Description

The invention relates to an electrical winding having a metallic winding conductor which forms individual windings, wherein the metallic winding conductor has a metallic conductor and an electrically insulating material enclosing the metallic conductor. Furthermore, the invention relates to an electrical insulation of a metallic, electrical conductor and the formation of an anodized Al-band for electrical windings.

When producing an electrical winding, in particular for use as a primary or secondary winding in the transformer construction, the electrical winding conductor must be electrically insulated. The winding conductor is continuously wound on a carrier, wherein the single winding of the winding conductor is defined by the carrier as a single winding in the following. In particular, the individual windings of the electrical winding conductor lying directly after a winding must have an electrical insulation with such an insulating effect that a voltage breakdown between the individual windings or within the winding is prevented. Especially for use in the medium and high voltage range, the use of a metallic conductor, in particular aluminum strip, in conjunction with a mostly made of plastics layer insulation (Geafol technique) is known.

A disadvantage of this technique, however, is that the plastics used have poor temperature properties and therefore the electric winding thus produced either have additional cooling systems or structurally larger than required dimensions must be.

For example, this describes the DE 40 06 697 A1 a transformer of small size, wherein the primary and secondary windings are wound around a core so that they overlap each other and at least one of the primary and secondary windings has a sheathed conductor made of insulating plastic. The insulation may alternatively consist of another insulating material, such as a resin. For example, this describes the DE 69 629 318 T2 a dry-insulated transformer whose high-voltage winding contains an insulating sleeve of thermoplastic resin and whose low-voltage winding is enveloped by an electrically conductive resin.

That's how it describes DE 2 215 979 a method for producing a film winding for transformers. According to the invention, conductive films can be coated with an electrically insulating oxal layer.

Furthermore, the FR 154 71 45 the electrolytic application of an aluminum oxide on an electrical conductor for thermal impregnation.

Furthermore, the EP 1 033 724 A1 the sheathing of an electrical conductor by means of an inorganic material oxide.

In the manufacture of electrical windings in the low voltage range, thin insulation can also be used due to the reduced breakdown voltages. Here, an aluminum conductor is used, on its surface By means of anodization, an aluminum oxide layer is formed, which provides sufficient insulation after the winding of this winding conductor produced in this way. When using high voltages and / or currents, however, this form of isolation is no longer sufficient.

The object of the present invention is therefore to provide an electrical winding which ensures sufficient insulation and nevertheless has good thermal conduction properties. Operating temperatures, line losses, conductor cross-sections and heat losses should be reduced according to the respective requirements and thus lead to smaller dimensions with lower weights and additional insulation.

According to the invention the object is achieved by an electrical winding according to claims 1-7. The metallic winding conductor has a metal dioxide layer surrounding the surface of the metallic conductor. Advantageously, the metal oxide layer is produced by means of an electrolytic oxidation process (anodization). Alternatively, the separate application of a metal oxide layer to the metallic conductor, e.g. Gluing or soldering, possible. Preferably, the electrical winding according to the invention consists of a strip material with an aluminum conductor, which is coated with an aluminum oxide layer.

In a preferred embodiment of the electrical winding according to the invention, the electrically insulating material has a variable thickness as a function of the maximum required dielectric strength within the electrical winding. If the thickness of the anodized layer is insufficient for insulation, additional insulation of lesser thickness may also be introduced according to the invention, as when using a conductor material without anodized layer. The combination of the insulating metal oxide layer and the overlying electrically insulating material prevents the voltage breakdown between the juxtaposed individual windings. However, the maximum required dielectric strength varies within the electrical winding, in particular due to structural and physical, eg due to non-linear impulse voltage distribution or thermal conditions, within the winding. Depending on these different maximum required dielectric strengths within the electrical winding, the thickness of the electrically insulating material used is likewise adapted. The greater the required, maximum required dielectric strength in a specific region of the electrical winding, the greater the thickness of the insulation, for example the thickness and / or the material properties, in particular the insulating material class, of the electrically insulating material, in the respective segment of the electrical winding. This makes it possible to reduce the size of the electrical winding and at the same time use the electrically insulating material more targeted and thus more cost-effective. According to the invention, the thickness of the metal oxide layer on the metallic conductor is varied in such a way that an insulating property continues to exist, depending on the maximum required dielectric strength within the electrical winding. Depending on the structural and in particular the physical, in particular thermal conditions, within the electrical winding can be provided due to a variation of the thickness of the electrically insulating material and / or the variation of the thickness of the metal oxide each a precisely tuned insulation for the electrical winding.

In a comparative embodiment of the electrical winding, the metal oxide layer has a constant thickness on the metallic conductor and the thickness of the electrically insulating material varies depending on the maximum required dielectric strength within the electrical winding. The metal oxide layer, such as the anodized layer on an aluminum conductor, has good temperature properties and thus reduces the thermal stress on the electrical winding. Depending on the maximum required dielectric strength within the electrical winding is provided according to the invention in the need for increased insulation, that the electrically insulating material has a variable thickness and / or variable material properties. In the case of an increased requirement for the insulation between the individual windings, the electrically insulating material is more strongly shaped and has a greater thickness and / or better material properties, such as a higher quality insulating classification. Conversely, in regions with a reduced requirement for insulation properties, an electrically insulating material, such as a plastic film, is chosen to be correspondingly thinner and / or reduced material properties are used. These material properties of the plastic film, such as the underlying insulating material class, can be varied depending on the necessary location-dependent dielectric strength. Depending on the maximum required dielectric strength within the electrical winding, according to the invention, the thickness of the electrically insulating material can be omitted almost to zero or even locally, so that the insulating effect between the individual windings is given at the corresponding points only due to the metal oxide layer of the electrical winding conductor.

In the event that certain minimum requirements are placed on the electrical insulation within the electrical winding, the invention provides that the electrically insulating material has a constant thickness and / or constant material property, in particular with respect to their insulating material, and depending on the maximum required withstand voltage within the electrical winding, the metal oxide layer has a different thickness. By specifying a constant thickness and / or material properties of the electrically insulating material, a minimum insulation property for the electrical winding is predetermined. Depending on the maximum required dielectric strength within the electrical winding, the metal oxide layer is adapted in terms of its thickness.

Advantageously, the condition of the metal oxide layer varies depending on the maximum required dielectric strength within the electrical winding.

Additionally and / or alternatively, a thin film can be run in during the winding process. If the dielectric strength at the most stressed point is still insufficient, you can let in a second or even third foil (parallel) here. As a result, only 2 materials need be used for the winding process: a) wrapping material with anodized layer of the same thickness and b) film of the same thickness. This does not require retooling operations during the winding process and allows for an efficient use of materials.

In particular, the purity of the anodized or applied metal oxide layer has a great influence on the insulation and thermal properties of the electrical winding. Above all, impurities within the metal oxide layer lead to an influence on the insulation and thermal properties. Through targeted use of appropriate starting and oxidation products for the preparation of the metal oxide and corresponding production methods, the insulation properties are influenced depending on the maximum voltage required within the electrical winding and thus implemented optimally and space-saving in the electrical winding according to the invention. In addition, depending on the maximum required withstand voltage within the electrical winding, the nature of the electrically insulating material varies.

Advantageously, the electrically insulating material contains paints, plastics, in particular plastic films, and / or paper. According to the invention, it is likewise provided that the electrically insulating material is constructed in layers. The layered construction ensures that, even if microscopically small damage to a layer, for example a plastic film layer, the adjacent layers of the electrically insulating material ensure insulation of the electrical winding. In addition, the variation of the material properties of the respective plastic film layer, in particular depending on the dielectric strength can be adjusted. Only with a complete damage of the electrically insulating material at one point an insulating effect of the electrically insulating material is no longer given. In addition, the metal oxide layer can be built up in layers.

An advantageous embodiment of the electrical winding is characterized in that the surface of the metal oxide layer and of the electrically insulating material are such that no relative displacements occur between the metal oxide layer and the electrically insulating material. The use of a, in particular roughened, surface ensures that a displacement of the electrically insulating material and of the conductor relative to one another is excluded during the production process and during operation, and thus a frequent and time-consuming check of the electrical winding with respect to its insulating properties is not necessary.

The object is further achieved by the features of the claims 8-12. For the isolation of a metallic, electrical conductor it is provided that the surface of the metallic, electrical conductor is coated with a metal oxide and the metal oxide layer is at least partially enveloped by an electrically insulating material. By the combination of the insulating properties of the metal oxide layer with the insulating property of an electrically insulating material enveloping it or additional insulation in foil form ensures optimum electrical insulation, which likewise can vary along the metallic, electrical conductor. The electrically insulating material advantageously contains paints, plastics, in particular plastic film and / or paper, wherein the electrically insulating material is advantageously constructed in layers and the electrically insulating material at least partially surrounds the metal oxide layer.

It is preferable to form an anodized Al strip as an electrical winding with insulating material, in particular, if the value of the winding voltage is to correspond to the value of the layer voltage in the sense of a high dielectric strength of electrical windings.

According to the invention, the anodized Al tape is first wound onto a metallic winding conductor with metal oxide layer to a coil, then several coils are arranged as segments of a total winding with taps electrically connected in series and lying in the overall winding at the input and output coil with additional layers of insulating material added, which may consist of additional film layers.

In this case, punctual additional insulation is provided at the taps at the beginning / end of the coils or the overall winding, wherein the punctual additional insulation should also consist of a foil, paper or insulating varnish.

It is advantageous between the coils to increase the axial breakdown protection from coil to coil in the overall winding provide additional insulation, such as air, a potting compound or insulating. Conveniently, for certain applications at the taps connections made of non-anodized Al-band.

Fig. 1

eine schematische Darstellung des Aufbaus eines erfindungsgemäßen elektrischen Wicklungsleiters;

Fig. 2

eine schematische Darstellung einer Einzelwicklung der erfindungsgemäßen elektrischen Wicklung während des Wicklungsprozesses;

Fig. 3

eine schematisch zusammengeführte Darstellung von Ausbildungen eines Al-Bandes als Spulen für elektrische Wicklungen (6) zu einer in Segmenten ausgeführten Gesamtwicklung;

Fig. 4

Schnitte nach Fig. 3 durch die Gesamtwicklung;

Fig. 5

Schnitte nach Fig. 3 durch ein Segment mit Anzapfungen (8) der Gesamtwicklung.

Further advantageous embodiments can be found in the dependent claims. The subject invention will be explained in detail with reference to the following figures. It shows:

Fig. 1

a schematic representation of the structure of an electrical winding conductor according to the invention;

Fig. 2

a schematic representation of a single winding of the electrical winding according to the invention during the winding process;

Fig. 3

a schematically merged representation of embodiments of an Al-band as coils for electrical windings (6) to a running in segments total winding;

Fig. 4

Cuts after Fig. 3 through the total winding;

Fig. 5

Cuts after Fig. 3 by a segment with taps (8) of the total winding.

The figure Fig. 1 shows a schematic representation of the metallic winding conductor 4 according to the invention. The metallic winding conductor 4 consists of a metallic aluminum conductor 1, at least one aluminum oxide layer 2 and a electrical plastic insulation film 3, which surrounds the metal oxide layer 2 or at least lies between two adjacent single windings lying one above the other. If segments are connected in series, only the final segments will receive this additional insulation, the segments in between will be carried out without additional insulation, except for the areas with taps. In this case, the electrical winding conductor 4 can either be completely enclosed by a metal oxide layer 2 or, alternatively, a metal oxide layer 2 can be present only at certain points of the metallic conductor 1. In the example of FIG Fig. 1 a metal oxide layer 2 is shown on the conductor 1 as a sheath of constant thickness, which is enclosed by an electrically insulating material 3 with a variable thickness. The electrically insulating material 3 can either be wrapped as an additional sheathing or as an intermediate layer around the metallic conductor 1 or alternatively only be placed at certain points on the metallic conductor 1 or on the metal oxide layer 2 of the electrical conductor 1.

In the figure Fig. 2 an electrical winding 6 according to the invention is shown, wherein the metallic conductor 1, the metal oxide layer 2 and the electrically insulating material 3 are wound on a carrier 5 in the form of a plastic film. The metal oxide layer 2 is arranged at least on the top and bottom of the metallic conductor 1. The support 5 is preferably designed as a cylindrical body and ensures, in the context of the production process of the electrical winding, that the electrically insulating material 3 and the metallic conductor 1 are wound on the metal oxide layer 2 in each case in defined paths one above the other. The winding conductor 4 thus formed is continuously wound onto the carrier 5 during the manufacturing process. In Axial direction exists in the present in the figure Fig. 2 example shown only an insulating effect with respect to the metal oxide layer 2 in the axial direction. In the radial direction relative to the carrier 5, the plastic film 3 is applied as an electrically insulating material as additional insulation on the respective metal oxide layer 2. In this way, depending on the maximum dielectric strength required within the electrical winding 6, a complete insulation of the electrical winding 6 is ensured and a partial reinforcement of the insulation can be achieved by metal oxide layer 2 or insulating layer 2 being reinforced at the points of highest stress loading.

Specifically, the show Fig. 3, 4 and 5 schematically the formation of an Al-band as turns for electrical windings 6 to a running in segments total winding, as they can be used in a transformer.

In Fig. 3 For reasons of clarity alone, the embodiments of the Al band as turns 6 are shown schematically combined to form the total winding executed in segments.

The Al-band forms the metallic conductor 1 and metallic winding conductor 4 and its sheathing anodized layer the metal oxide layer 2. The anodized Al-tape is applied to the removable carrier 5 (FIG. Fig. 2 ) wound into a coil 6.

The arrangement and electrically connected in series connection of several coils 6 as segments of the overall winding with taps 8 is in the Fig. 3 seen. The coil 6 located in the overall winding at the entrance is supplemented with layers 3.1 of insulating material 3 which are additionally wrapped only at the beginning 7, the subsequent coil 6 has only layers of the anodised one Al-band as a metallic conductor 1 with metal oxide 2 on and lying in the overall winding at the output coil 6 is in turn supplemented with only at the end 7 additionally wrapped layers 3.1 of insulating material. 3

Show accordingly Fig. 4 Cuts after Fig. 3 through this overall winding and analog Fig. 5 Cuts through each segment with taps 8 of the total winding, from which in conjunction with Fig. 3 selective additional insulation 9 can be seen at the taps 8 at the beginning / end of the overall winding 7. If you look in FIG. 5 presents the central axis, so the taps (and thus the additional insulation) are visible only on one half of the representation.

The additional layers 3.1 and the punctual additional insulation 9 at the taps 8 at the beginning / end of the overall winding 7 consist of Kusntstofffolie, paper or paint and not shown terminals of the taps 8 and the connections for winding or coil beginning and winding or coil end from non-anodised A1 tape.

Claims (12)

1. Electrical winding (6) having a metallic winding conductor (4), which forms individual windings, the metallic winding conductor (4) having a metallic conductor (1) and an electrically insulating material (3) surrounding the metallic conductor (1), characterized in that the metallic winding conductor (4) has a metal oxide layer (2), which at least partially envelops the surface of the metallic conductor (1), wherein, depending on the maximum required dielectric strength within the electrical winding (6), the metal oxide layer (2) has a variable thickness.
2. Electrical winding (6) according to Patent Claim 1, characterized in that, depending on the maximum required dielectric strength within the electrical winding (6), the electrically insulating material (3) has a variable thickness and/or variable material properties.
3. Electrical winding (6) according to either of the preceding Patent Claims 1 and 2, characterized in that, depending on the maximum required dielectric strength within the electrical winding (6), the construction of the metal oxide layer (2) varies.
4. Electrical winding (6) according to one of Patent Claims 1 to 3, characterized in that the electrically insulating material (3) contains enamels, plastics, in particular plastic foils, and/or paper.
5. Electrical winding (6) according to one of Patent Claims 1 to 4, characterized in that the electrically insulating material (3) and/or the metal oxide layer (2) has a stratified design.
6. Electrical winding (6) according to one of the preceding Patent Claims 1 to 5, characterized in that, depending on the maximum required dielectric strength within the electrical winding (6), the construction of the electrically insulating material (3) varies.
7. Electrical winding (6) according to one of Patent Claims 1 to 6, characterized in that the surface of the metal oxide layer (2) and of the electrically insulating material (3) are constructed such that no relative displacements between the metal oxide layer (2) and the electrically insulating material (3) occur.
8. Formation of an anodized Al strip as the electrical winding (6) with insulating material (3) according to one of Claims 1 to 7, characterized in that

   - the anodized Al strip, which has been wound onto the removable support (5) to form a coil (6), is present as the metallic winding conductor (4) with a metal oxide layer (2),

   - the arrangement and connection (electrically in series) of a plurality of coils (6) as segments of an entire winding with taps (8) are formed, and

   - the coils (6) positioned at the input and at the output in the entire winding are supplemented by additional layers (3.1) of insulating material (3).
9. Formation of an anodized Al strip as the electrical winding (6) with insulating material (3) according to Claim 8, characterized in that additional insulations (8.1, 9) at points are arranged at the taps.
10. Formation of an anodized Al strip as the electrical winding (6) with insulating material (3) according to either of Claims 8 and 9, characterized in that the additional layers (3.1) consist of foil.
11. Formation of an anodized Al strip as the electrical winding (6) with insulating material (3) according to either of Claims 9 and 10, characterized in that the additional insulations (9) at points consist of foil.
12. Formation of an anodized Al strip as the electrical winding (6) with insulating material (3) according to one of Claims 8 to 13, characterized in that terminals consisting of a nonanodized Al strip are provided at the taps (8).

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