EP2863402A1 - Strip winding for high voltage transformers - Google Patents

Abstract

The invention relates to a belt winding for high-voltage transformers, comprising a strip conductor (10, 30, 70) with a rectangular cross section, which in a plurality of winding layers (52, 54, 56, 58, 60, 62, 64) is arranged spirally about a winding axis (44) , The strip conductor (10, 30, 70) is in turn formed from at least two individual conductors (12, 14, 16, 32, 34), likewise of rectangular cross-section, arranged side by side in one layer, wherein the individual conductors (12, 14, 16, 32, 34) along the extension of the strip conductor (10, 30, 70) in at least one exchange region (18, 38, 72, 74) in each case cyclically interchanged (66) and whereby thereby a respective axial (44) offset of the respective individual conductors (12, 14 , 16, 32, 34) is effected. The invention also relates to a high-voltage transformer with a strip winding according to the invention.

Description

The invention relates to a tape winding for high-voltage transformers, comprising a strip conductor with a rectangular cross-section, which is arranged in a plurality of winding layers spirally about a winding axis. The invention also relates to a corresponding high-voltage transformer.

It is generally known that high-voltage transformers in the voltage range of, for example, 1 kV to 60 kV on the low side often include so-called hoop windings. Tape windings have a strip conductor with a rectangular cross-section, which is arranged spirally similar to a winding axis, wherein a winding layer is formed only by a single turn of the strip conductor. Thus, by a small number of turns, for example 20, both a low voltage to be induced in such a case, for example on the low voltage side 3 kV, as well as a high cross section of the strip conductor corresponds to a correspondingly high undervoltage side current, for example 500A. In addition, a high filling factor is achieved by the rectangular cross section of the strip conductor. Band conductors are made of a metal such as copper or aluminum, for example, and are surrounded by a layer of insulating material to avoid a short circuit between adjacent turns.

A disadvantage here proves that in particular by the proximity effect - that is, a current displacement - causes a current density over the relatively large cross section of the strip conductor results, which is higher in its edge regions than in the central region. The causing magnetic field is the stray field of the transformer. This is associated with increased additional losses and hot spots in the edge regions of a respective tape winding.

Based on this prior art, it is an object of the invention to provide a tape winding, which is characterized by lower losses and a more homogeneous temperature distribution. It is also an object of the invention to provide a suitable transformer.

This object is achieved by a tape winding of the type mentioned. This is characterized in that the band conductor in turn is formed from at least two band-like individual conductors arranged side by side in a layer also rectangular in cross-section and that the individual conductors along the extension of the strip conductor in at least one exchange area are cyclically interchanged with each other whereby thereby a respective axial offset of the respective individual conductors is effected.

The basic idea of the invention consists of constructing the strip conductor from a plurality of mutually insulated individual conductors, which are cyclically reversed in their position within the cross section of the strip conductor formed by them. The additional losses are advantageously reduced by the fact that the position of the conductor is changed in causing magnetic field. A pure axial segmentation of mutually insulated individual conductors - that is, without cyclic exchange - brings no outstanding effect, since here the induced eddy currents can still form, for example via the Ausleitungsschienen circular currents between the individual conductors. By axial transposition - ie a cyclic exchange of individual conductors - the eddy current losses are effectively reduced. As a result of the cyclic exchange of the individual conductors, each individual conductor ideally assumes any axial position over its entire length, so that in an advantageous manner asymmetries, which are based on different axial positions, are at least substantially compensated. A holding together of neighboring individual leaders the strip conductor can be effected, for example, by an enveloping insulation, for example a resin-based insulation and / or a wound insulation.

The tape winding is in this case axially in two or preferably three or more parallel individual conductors, which are preferably coated on both sides insulating performed. The individual conductors are exchanged cyclically at regular or irregular intervals, so that the individual conductors occupy the next position in the axial direction after an exchange. The outermost (last) single conductor in exchange direction is led to the outermost (first) position.

According to a preferred embodiment variant of the strip winding according to the invention, the number of longitudinal sections of the strip conductor formed by the exchange regions corresponds approximately to the same length of the longitudinal sections to the number of individual conductors or to an integral multiple thereof. This advantageously ensures that each individual conductor is arranged on the middle with an equally long longitudinal section at each of the respective possible axial positions, so that any position-related asymmetries of an respectively induced voltage are at least almost equalized.

According to a particularly preferred embodiment variant of the tape winding according to the invention, the individual conductors are folded in a respective exchange region. A folding, for example by 45 °, is a suitable method for band-like conductors to direct the actually straight course of the band-shaped individual conductor in a different direction and thus to effect an axial offset. A respective thickening of the strip conductor by the factor in the exchange or folding region is negligible in so far as, for example, only three individual conductors ultimately only two exchange areas are necessary to achieve symmetry of each induced in the individual conductors voltage. For a total number of turns of 20, for example, this is of little consequence.

A further advantageous embodiment variant of the tape winding according to the invention is following exactly a single conductor in a respective exchange region by a quadruple folding from an axial outer position to the opposite offset axial outer position, the remaining individual conductors are each offset by a double folding by one axial position.

The individual conductors are first folded at a 45 ° angle to the left or right. Then the single conductors are folded back at a further 45 ° angle at the next axial position in the winding direction. The outermost (last) single conductor in the exchange direction, however, folded at 180 ° angle under the individual conductors. Then another folding takes place by 180 ° in the opposite direction. Finally, a folding takes place in the winding direction at a 45 ° angle to the first axial position in the exchange direction. Such a folding advantageously makes it possible for the folded individual conductors in the folding area to adjoin one another in a form-fitting manner, and thus a particularly space-saving arrangement is realized which does not lead to an avoidable thickening of the strip conductor in the folding area.

According to a further advantageous variant of the invention, the axial offset of a respective individual conductor corresponds exactly to the width of a single conductor or an integral multiple thereof. This ensures that the axial positions, which a single conductor can assume within the cross section of the strip conductor formed by a plurality of individual conductors, are always the same. Thus, an over the entire length of the strip conductor constant shape is ensured in an advantageous manner, with the exception of the respective exchange areas, which are characterized by a slight thickening by about a factor of three.

According to a further variant of the invention, the individual conductors are at least predominantly surrounded by a layer of insulating material. It is on the one hand to provide an electrical insulation of the individual conductors of a strip conductor with each other, as well as for an isolation of adjacent layers of the strip conductor. This is achieved in an advantageous manner that no short circuit of different voltage potentials of adjacent winding layers takes place.

The object according to the invention is also achieved by a high-voltage transformer comprising at least one transformer core and a strip winding according to the invention. The associated advantages correspond to the advantages of the tape winding according to the invention already explained above. In particularly preferred Way, the high voltage transformer is designed three-phase and thus suitable for a typical power distribution network.

Further advantageous embodiment possibilities can be found in the further dependent claims.

Reference to the embodiments illustrated in the drawings, the invention, further embodiments and other advantages will be described in detail.

Fig. 1

einen ersten exemplarischen Bandleiter,

Fig. 2

einen zweiten exemplarischen Bandleiter,

Fig. 3

einen Querschnitt eine durch exemplarische Spule mit Bandwicklung,

Fig. 4

einen dritten exemplarischen Bandleiter,

Fig. 5

exemplarische erste Arbeitsschritte beim Falten von Einzelleitern sowie

Fig. 6

exemplarische zweite Arbeitsschritte beim Falten von Einzelleitern.

Show it:

Fig. 1

a first exemplary band leader,

Fig. 2

a second exemplary band leader,

Fig. 3

a cross section through an exemplary coil with tape winding,

Fig. 4

a third exemplary band leader,

Fig. 5

exemplary first steps in folding individual leaders as well

Fig. 6

exemplary second steps in folding single ladders.

Fig. 1 shows a first exemplary band conductor 10 in a plan view. The strip conductor 10 is formed by three mutually insulated individual conductors 12, 14, 16, which are cyclically exchanged in an exchange region 18. Hereby, a respective individual conductor 12, 14, 16 changes from one of the possible axial positions 20, 22, 24 to one of the other possible positions 20, 22, 24. The band-like shape of the strip conductor is not adversely affected thereby, only in the exchange region 18 occurs slight thickening on.

Fig. 2 shows a comparable second exemplary band conductor 30 in a plan view. The strip conductor 30 is formed by two insulated individual conductors 32, 34, which are exchanged cyclically in a exchange region 36. Hereby the single conductor 32 changes from an axial position 38 into an axial position 40 or the individual conductor 34 from the axial position 40 into the axial position 38.

Fig. 3 shows a cross section through an exemplary coil with coil winding in a sectional view 40. Around a bobbin 42 around a winding axis 44 around a winding winding 44 with a belt winding with seven winding layers 52, 54, 56, 58, 60, 62, 64 of a strip conductor is arranged. The strip conductor itself has in each case three individual conductors, which are each arranged either in a first 46, second 48 or third 50 axial position or axial position range within the cross section of the strip conductor. A respective cyclic exchange of the position of the individual conductors is indicated by the arrows indicated by the reference numeral 66. Thus, it is ideally ensured that each individual conductor occupies each axial position with a respective equal section length, so that any asymmetries of the voltages induced in the individual individual conductors that are caused by the different axial positions advantageously at least approximately compensate each other.

FIG. 4 3 shows a third exemplary ribbon conductor 70 having three single conductors and two exemplary exchange regions 72, 74. On both sides of the exchange regions 72, 74, longitudinal sections 76, 78, 80 of the individual conductors are formed, in which the individual conductors run in a respectively exchanged axial position.

The Figures 5 and 6 are exemplary steps in the folding of a strip conductor with three individual conductors. In steps A and B is shown how the three conductors of a strip conductor are folded at a 45 ° angle by 90 ° upwards. In steps C and D, the originally axially lower two individual conductors are folded back in a further 45 ° folding back into an axial position offset by a width of a single conductor upwards. In step E is shown how the originally axially upper single conductor is folded by 180 ° and is guided vertically below the other individual conductors down, where it is then guided by a further 180 ° folding back up, as shown in step F. By a further 45 ° folding takes place in a step G, the assumption of the individual conductor initially located in the uppermost axial position of the strip conductor in the now axially lowest position of the strip conductor, as shown in step H. Thus, a cyclic phase change of the individual conductors is realized by folding.

LIST OF REFERENCE NUMBERS

10

first exemplary band leader

12

first single conductor of the first band leader

14

second single conductor of first band leader

16

third single conductor of first band conductor

18

Exchange area of first band leader

20

first axial position in first band conductor

22

second axial position in the first band conductor

24

third axial position in first band conductor

30

second exemplary band leader

32

first single conductor of the second band leader

34

second single conductor of second band conductor

36

Exchange area of second band leader

38

first axial position in second band conductor

39

second axial position in second band conductor

40

Cross section through exemplary coil with ribbon winding

42

bobbins

44

winding axis

46

first axial position in ribbon conductor of ribbon winding

48

second axial position in ribbon conductor of ribbon winding

50

third axial position in ribbon conductor of ribbon winding

52

seventh winding layer of tape winding

54

sixth winding layer of tape winding

56

fifth winding layer of tape winding

58

fourth winding layer of tape winding

60

third winding layer of tape winding

62

second winding layer of tape winding

64

first winding layer of tape winding

66

cyclic exchange

70

third exemplary band leader

72

first exchange area of third band leader

74

second exchange area of third band conductor

76

first longitudinal section of third band conductor

78

second longitudinal section of third band conductor

80

third longitudinal section of third band conductor

90a

Steps A, B, C, D for folding a strip conductor

90b

Steps E, F, G, H for folding a strip conductor

Claims (9)

A tape winding for high-voltage transformers, comprising a strip conductor (10, 30, 70) with a rectangular cross section, which is arranged in a plurality of winding layers (52, 54, 56, 58, 60, 62, 64) spirally around a winding axis (44),
characterized.
in that the strip conductor (10, 30, 70) in turn is formed from at least two individual conductors (12, 14, 16, 32, 34), likewise of rectangular cross-section, arranged in one layer and that the individual conductors (12, 14, 16, 32, 34) along the extension of the strip conductor (10, 30, 70) in at least one exchange region (18, 38, 72, 74) in each case cyclically interchanged with each other (66) whereby a respective axial (44) offset of the respective individual conductors (12, 14, 16, 32, 34) is effected. Tape winding according to Claim 1, characterized in that the number of longitudinal sections (76, 78, 80) of the strip conductor (10, 30, 70) formed by the exchange regions (18, 38, 72, 74) is approximately the same length of the longitudinal sections (78 , 78, 80) corresponds to the number of individual conductors (12, 14, 16, 32, 34) or an integer multiple thereof. Tape winding according to claim 1 or 2, characterized in that the individual conductors (12, 14, 16, 32, 34) are folded (90a, 90b) in a respective exchange region (18, 38, 72, 74). Tape winding according to claim 3, characterized in that exactly one individual conductor (12, 14, 16, 32, 34) in a respective exchange region (18, 38, 72, 74) by a quadruple folding from an axial outer position to the opposite axial ( 44) is offset from the outer position, wherein the remaining individual conductors (12, 14, 16, 32, 34) in each case by a double folding around one axial (44) position (20, 22, 24, 38, 40, 46, 48, 50 ) are offset. Tape winding according to claim 4, characterized in that the quadruple folding amount by 45 °, 180 °, 180 ° and 45 ° and the double folding by 45 °. Tape winding according to one of the preceding claims, characterized in that the axial (44) offset of a respective individual conductor (12, 14, 16, 32, 34) exactly the width of a single conductor (12, 14, 16, 32, 34) or an integer Multiples of it corresponds. Tape winding according to one of the preceding claims, characterized in that the individual conductors (12, 14, 16, 32, 34) are at least predominantly surrounded by a layer of insulating material. A high voltage transformer comprising at least one transformer core and a ribbon winding according to any one of claims 1 to 7. High-voltage transformer according to claim 8, characterized in that it is designed in three phases.

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