HK1080211B

HK1080211B - Winding arrangement

Info

Publication number: HK1080211B
Application number: HK05112223.9A
Authority: HK
Inventors: Peter Heinzig; Jens Hoppe; Dietmar Jahnel
Original assignee: 西门子公司
Priority date: 2002-08-16
Filing date: 2003-07-30
Publication date: 2007-12-07
Also published as: DE10238521B4; CN1331171C; BR0313483A; AU2003264248A1; HK1080211A1; EP1529296A1; EP1529296B1; CN1672226A; CA2495382C; BRPI0313483B1; CA2495382A1; WO2004019351A1; DE10238521A1

Abstract

The invention relates to a winding arrangement having a high electric strength. The winding arrangement has at least two juxtaposed windings (34, 37) arranged in a row, said windings being surrounded by a barrier arrangement (38, 40) configured with insulating material. A tubular electric shield (62, 63; 64, 65) is provided in the area of both front faces of the winding (5, 6; 7, 8; 58, 59; 60, 61) of at least one of said windings (1, 3, 4), said shield coaxially surrounding the corresponding winding (1, 2; 3, 4; 37) while leaving an intermediate gap (23A, 63A) and extending axially outward over the corresponding front face of the winding (5, 6; 7, 8; 58, 59; 60, 61) in such a way that its axial height (B) relative to the corresponding front face of the winding (58, 59) is the same or greater than half of the radial width (A) of the intermediate gap (23A, 63A).

Description

Winding arrangement

Technical Field

The invention relates to a winding arrangement having at least two windings arranged in parallel in a row.

Background

From us patent 4318066, a transformer winding is known which is surrounded coaxially by a tubular electrical shield. The shield extends along the entire axial length of the winding and ends with the two winding end sides. Between the winding and the electrostatic shield, three further tubular shields are provided which surround the winding and which are stepped from the outside to the inside in decreasing axial length and all end with the upper winding end side of the winding. There are also connections for the windings. These electrostatic shields, whose length varies, are used to achieve a uniform voltage distribution along the winding when the winding is subjected to a pulsed voltage; in this case, the electrostatic shield acts like a capacitor to discharge the overvoltage protection.

For example, a winding arrangement for a choke coil, which has at least two windings arranged in parallel in a row, may for example have a respective core, wherein each of the windings surrounds a limb of the core, which limb connects outside the winding to the core yoke in a closed magnetic circuit. Furthermore, the winding arrangement is usually mounted in a container which is composed of electrically conductive walls and which is filled with an insulating medium, for example cooling oil.

Such a winding arrangement can also be provided for a transformer, in which case each of the two windings forms a transformer winding of the respective transformer winding combination. The transformer windings formed from these windings are each assigned to one phase and one electrical side of the transformer, for example the primary side, and each of the transformer winding combinations has a second transformer winding which forms the other electrical side of the respective phase.

In particular, when using the winding arrangement in a choke or a transformer of a high-voltage direct-current transmission system (HG *), the winding is supplied with a direct-current voltage in addition to an alternating-current voltage with higher harmonics. The windings must therefore be designed for the application of such higher harmonics or dc voltages. Accordingly, the windings are subjected to corresponding ac and dc voltage tests before being put into operation. In such a dc voltage test, the windings are supplied with the test dc voltage one after the other or all together.

Disclosure of Invention

The invention aims to provide a winding device with high insulation strength.

The above-mentioned object is achieved by a winding arrangement comprising at least two windings arranged in a row in parallel, each of which is surrounded by a blocking device made of insulating material, and comprising at least one tubular electrical shield in each of the two winding end sides of one of the windings, which electrical shield coaxially surrounds the at least one winding with a gap left and extends axially beyond the respective winding end side in such a way that its height in the axial direction beyond the respective winding end is equal to or greater than half the radial width of the gap.

By the windings being surrounded by a blocking device of insulating material, respectively, an effective electrical insulation is provided with respect to the core limb which may be present and also with respect to the container which may be present in which the winding device is mounted and in which the container wall may be magnetically shielded on its inner side, i.e. with respect to those parts which are located outside the windings. In addition, the tubular electrical shield provided in the region of the end face of each winding leads to the electric field being guided there in such a way that the blocking device there carries as little electrical load as possible. The blocking device therefore has at least one wall made of insulating material which surrounds the winding and in particular the radially outer winding edge formed by the winding outer surface and the winding end face on the winding end face of a winding, so that by means of the shield, in particular, the electric field strength which is formed between the shield and the corresponding winding, in particular the winding edge of the winding, and which is generated, for example, when a dc voltage is applied or the winding is subjected to a dc voltage test, enters the blocking device substantially perpendicularly to the wall surface of the blocking device or is discharged again from the blocking device. A small tangential component of the electric field strength, i.e. in the direction of the wall surface of the blocking means, thus occurs here. In the case of a design without shielding, a substantially axially oriented electric field is formed when such a direct voltage is applied, in particular in the region of the blocking device in which the winding edges of two adjacent windings are adjacent to one another. As a result, large electric field strengths are generated tangentially along the wall surface of the blocking means in the region of the blocking means adjacent to the outer winding edge, which can lead to electrical defects. If the shields are designed such that, with respect to the respective winding head side, the respective shield extends over the winding head side by a height, good guidance of the electric field is ensured if this height is at least equal to half the radial width of the gap. This height must be increased correspondingly when the radial width of the gap becomes larger. The design of the winding arrangement according to the invention has proved particularly advantageous, in particular when the winding arrangement according to the invention is used in a choke, in which case two electrical windings are connected in parallel. Furthermore, by using the blocking device and the electrostatic shield, a particularly compact design of the winding arrangement and of the container is achieved, since the electric field generated, in particular when a direct voltage is applied, is directed as already described and homogenized in the outward direction, thereby reducing the probability of flashovers between one of the windings and electrically conductive parts arranged outside this winding and at different potentials. A particularly safe electrical winding arrangement is obtained if all windings are provided in their winding end regions with such a shielding as is provided at least one winding.

In a preferred embodiment, the two electrical shields are formed together by a continuous tubular overall shield which extends axially over the entire winding. Corresponding shielding to the outside is thus achieved along the entire winding. This has proven to be particularly advantageous when the winding arrangement according to the invention is installed in a container in which, for improved guidance of the magnetic field, laminated cores are arranged outside the windings, oriented parallel to the core yoke, and are mounted in the container wall inside the container. In the absence of an electrical shield in the winding arrangement, the field strength increases at the corners and edges that are normally present in the laminated core, which can lead to flashovers between the winding and the laminated core. Due to this electrical shielding, the electric field distribution between the winding and the vessel wall or the laminated core is homogenized, whereby the risk of flashovers between the winding and the vessel wall is significantly reduced.

Preferably, the winding arrangement forms a choke of a high voltage direct current transmission system (HG * system). The winding arrangement according to the invention is particularly suitable for such a choke.

In a further preferred embodiment, each of the two windings forms an outer transformer winding of the respective transformer winding combination, wherein each transformer winding combination has an outer transformer winding which surrounds an inner transformer winding. The two transformer windings are magnetically coupled and used for the conversion of an electrical phase of, for example, a polyphase network.

Preferably, the winding arrangement is an integral part of a HG * system transformer. In this HG * system, the transformer may apply a high DC voltage; due to the design according to the invention, the winding arrangement is therefore particularly well suited for such transformers.

The blocking device can be designed, for example, for surrounding the outer winding edge, such that the wall is formed by a tube of insulating material which extends beyond the winding ends and surrounds the winding in the radial direction and a respective disk of insulating material which encloses the tube of insulating material in the form of a cap at each end. In a preferred embodiment, each blocking device has at least one rounded outer angular ring in the region of the winding ends, which surrounds the outer winding edge.

In a preferred embodiment, the shield has a field-guiding shield in the region of its ends. By means of this shielding device for field guidance, high field strength densities in the region of the shielding ends are avoided.

Preferably, the winding arrangement is housed in an electrically conductive container.

Drawings

The winding arrangement according to the invention is explained in detail below with the aid of the drawing. In the drawings:

fig. 1 shows a sectional view of a choke with a winding arrangement according to the invention;

fig. 2 shows a transformer with a winding arrangement according to the invention;

fig. 3 shows a partial winding arrangement with a shielding device for field guidance according to a first variant; and

fig. 4 shows a partial winding arrangement with a shielding device for field guidance according to a second variant.

Detailed Description

Fig. 1 shows a winding arrangement comprising two windings 1 and 2 arranged side by side in a row and extending along axes 85 and 86, respectively. The electrical connections of the windings 1 and 2 are omitted in fig. 1 for the sake of clarity of the illustration. Each winding 1 and 2 is surrounded by a blocking device 3 or 4, respectively, made of insulating material. Each blocking device 3 and 4 has an outer angled ring 9, 10 or 11, 12 on each winding end side 5, 6, 7 and 8. Likewise, inner angle rings 13, 14 or 15, 16 are provided on the winding end sides 5, 6 or 7, 8. The outer angular rings 9, 10 or 11, 12 surround the radially outer winding edges 19 or 20 and 21 or 22, respectively, which are formed by the winding outer surfaces 17 or 18 and the adjacent winding end sides 5 or 6 and 7 or 8. The inner corner rings 13, 14 or 15, 16 each surround a radially inner winding edge 19A, 20A or 21A, 22A.

For shielding purposes, a tubular overall shield 23 or 24 is provided in the region of the winding ends 5, 6 or 7, 8 of the two windings 1 and 2. The total shields 23 and 24 surround the winding 1 or 2 with the gaps 23A and 24A left and are connected to ground, i.e. to ground potential via a connecting device. The overall shielding 23 and 24 in this case extends along the entire axial length of the respective winding 1 or 2 and projects beyond the winding ends at the winding ends 5, 6 or 7, 8, to be precise in such a way that, as illustrated at the overall shielding 23, its height B, which is extended in the axial direction relative to the winding ends 5, is greater than half the radial width a of the gap 23A.

For example, the winding edge 19 is observed, which is electrically insulated particularly well by means of the outer angle ring 9 with respect to electrically conductive parts arranged outside the winding 1, such as the core 25, the container 26 or the laminated core 28 mounted on its wall 27 in the container 26. In this region, it is additionally achieved by the overall shield 23 that the electric field generated in operation or during the dc voltage test in the region of the winding edge 19, which arises from the winding end face 5 and the winding outer surface 17, is guided in such a way that it runs almost perpendicular to the surfaces 29 and 30 of the outer angle ring 9 and ends at the shield 23. In operation with the application of a dc voltage or in dc voltage tests, the electrical load of the blocking device 3 is therefore low in the region of the winding edges 19.

If total shields 23 and 24 are not present, in particular when a dc voltage is applied to windings 1 and 2, in particular simultaneously, an electric field is generated in the region of winding edges 19 and 21 that are very close to one another, i.e. in core window 31 of core 25, which electric field extends substantially axially, i.e. no longer perpendicularly to surfaces 29 and 39 of outer angle ring 9 and the corresponding surface of outer angle ring 11. This results in a high electrical load along the surface 29 or 30, in particular in the region near the winding edge 19, which can lead to electrical defects.

The blocking devices 3 and 4, including their outer angular rings 9, 10, 11 and 12 and inner angular rings 13, 14, 15 and 16, are in particular made of pressed board (Presspan).

The transformer tank 26 may be filled with an insulating medium, such as cooling oil.

In addition, the total shield 24 may also be omitted. It is likewise possible to omit the core 25 and thus obtain a coreless choke.

Fig. 2 shows a sectional view of a winding arrangement intended for a two-phase transformer.

Two transformer winding assemblies 32 and 33 are provided, which extend along the axes 87 and 88, respectively, wherein the transformer winding assembly 32 has an outer transformer winding 34 and an inner transformer winding 35, and the second transformer winding assembly 33 comprises an outer transformer winding 37 and an inner transformer winding 36. Each outer transformer winding 34 and 37 coaxially surrounds each inner transformer winding 35 or 36. The electrical connections of the transformer windings 34, 35, 36 and 37 are also not shown here for the sake of clarity of the illustration. Each transformer winding 34, 35, 36, 37 is surrounded by a blocking device 38, 39, 40, 41 assigned to it. Each blocking device 38, 39, 40, 41 has an outer angle ring 42, 43, 44, 45, 46, 47, 48 and 49 similar to outer angle rings 9, 10, 11 and 12 according to fig. 1 and an inner angle ring 50, 51, 52, 53, 54, 55, 56, 57 similar to inner angle rings 13, 14, 15 and 16 according to fig. 1.

In the region of the winding end sides 58, 59, 60 and 61 of the outer transformer windings 34 and 37, electrical shields 62, 63 or 64 and 65 are provided which surround the transformer windings 34 or 37 in a tubular manner. The electric shields 62, 63, 64, and 65 surround their respective windings while constituting respective gaps 62A, 63A, 64A, or 65A. In contrast to the winding arrangement according to fig. 1, two separate shielding elements 62 and 63 are used here, for example at the location of the total shielding element 23, which each extend along only a part of the axial length of the transformer winding 34. In other words, the total shielding 23 and 24 unifies the function of the two shielding members 62 and 63 or 64 and 65, respectively. The shielding elements 62, 63, 64 and 65 likewise project axially from the respective winding head side 58, 59, 60 and 61 in such a way that, as is illustrated in the example of the shielding element 62, their respective height D, which extends axially beyond the winding head side 58, 59, 60, 61, is at least equal to half the radial width C of the gap 62A.

The winding arrangement according to fig. 2 is accommodated in a transformer tank 66. Each transformer winding combination 32 and 33 surrounds one leg 67 or 68 of the transformer core 69; the core legs 67 and 68 are connected to form a closed magnetic circuit by core yokes 70 and 71. Laminated cores 74 and 75 are provided on the inner sides 72 and 73 of the transformer tank 66 for improved guidance of the magnetic field.

In this arrangement, the blocking means 38 to 41 can also be formed by pressed plates, and the transformer tank 66 can likewise be filled with an insulating medium, for example cooling oil.

The electric shields 62, 63, 64 and 65 have the same task as the total shields 23 and 24 according to fig. 1, namely to guide the magnetic field, in particular in the core window 76 of the transformer core 69, in such a way that the magnetic field passes tangentially through the outer angle rings 46 and 42 or 43 and 47 and the blocking devices 38 and 40 generate a low electrical load.

Instead of the overall shielding 23 and 24 according to fig. 1, shielding elements 62 to 65 shown in fig. 2 can also be provided there.

In contrast, in the winding arrangement according to fig. 2, the shielding elements 62 and 63 and/or 64 and 65 according to fig. 2 can be replaced by corresponding overall shielding elements which are continuous in the axial direction, as shown in fig. 1. Thus, the shields 62 and 63 are jointly, i.e. integrally, constituted by a total shield extending continuously in the axial direction along the entire winding; the same applies to the shields 64 and 65. Note that the transformer core 69 may be omitted here. In this embodiment, the shielding elements 64 and 65 can also be omitted, it being sufficient for the shielding effect to have the shielding elements 62 and 63, but in order to achieve a particularly good shielding effect, the shielding elements 62, 63, 64 and 65 are provided in the region of all the winding ends 58 to 61.

The blocking devices 3, 4 according to fig. 1 and the blocking devices 38 to 41 according to fig. 2 can also be designed in multiple layers, i.e. with a plurality of outer and inner angular rings.

The shields 62 to 65 and 84 and the total shields 23 and 24 can have shielding means for field guidance in their end regions, as is shown in fig. 3 and 4, respectively.

Fig. 3 shows a detail in the region of the winding end 79 of the winding 77. The winding 77 extends along an axis 78 and is surrounded, with a gap 80 left, by a shield 81, which can be regarded as representative of the shields 62 to 65 or of the total shields 23 and 24. In the region of its end 82, the shield 81 has a shielding 83 for field guidance. It extends around the axis 78 and in the circumferential direction of the shield 81 along an end 82. The shielding device has two electrically conductive wires 84 and 84A, which are electrically insulated by respective insulation means 89 and 89A and together by a total insulation means 90. Both of these two conductive lines 84 and 84A are connected to ground potential. The two wires 84 and 85 are broken at least once along their length along the circumference of the shield 81 so as not to form a closed loop. The shielding 83 serves to avoid too high a field strength or a high field density in the region of the end 82 of the shield 81.

Fig. 4 shows a modified shielding device 91 for field guidance; in contrast to the shielding 93 according to fig. 3, it has a single electrically conductive line 92, which is surrounded by an electrically insulating device 93. The conductive wire 92 is also connected to ground potential and is also interrupted at least once along its length along the circumference of the shield 81 so as not to form a closed loop.

The shielding means 83 and 91 should ensure that no field strengths are generated too high at the end 82 of the shield 81. It may also be designed as an annular, for example circular or oval, cross-section conducting tube along the end of the shield 81 about the axis 78. Likewise, instead of a tube, a conductive film on a correspondingly shaped support can be used. The shielding means 83 and 91 may also be constituted by the shielding 81 itself, for which purpose the bent shielding 81 constitutes a rounded edge, or it may also be bent in such a way that its bent part forms a ring-shaped tube.

The shielding elements 62 to 65 and the overall shielding elements 23 and 24 can each have a shielding 83 or 91 in their end regions for field guidance.

Claims

1. A winding arrangement comprises at least two windings (34, 37) which are arranged in parallel and are each surrounded by a blocking device (38, 40) made of insulating material, and in each case one tubular electrical shield (62, 63) in the region of each of the two winding end faces (58, 59) of at least one of the windings (34), wherein each shield (62, 63) surrounds at least one winding (34) coaxially with a gap (23A) left and extends axially beyond the winding end face (58, 59) in an outward manner such that its height (B) which is axially offset with respect to the winding end face (58, 59) is equal to or greater than half the radial width (A) of the gap (23A).

2. A winding arrangement according to claim 1, wherein: the two electrical shields are jointly formed by a continuous tubular overall shield (23, 24) which extends axially over the entire length of the windings (1, 2).

3. A winding arrangement according to claim 1 or 2, wherein: the winding arrangement forms a choke for a high-voltage direct-current transmission system.

4. A winding arrangement according to claim 1 or 2, wherein: each of the two windings (34; 37) forms an outer transformer winding (34; 37) of a transformer winding combination (32; 33), wherein each transformer winding combination (32, 33) has an inner transformer winding (35; 36) surrounded by the outer transformer winding (34; 37).

5. A winding arrangement according to claim 4, wherein: the winding arrangement is part of a transformer for a high-voltage direct-current transmission system.

6. A winding arrangement according to claim 1 or 2, wherein: the blocking devices (3, 4; 38, 40) each have at least one outer angled ring (9-12; 42, 43, 46, 47) in the region of the winding end faces (5, 6; 7, 8; 58, 59; 60, 61), which surrounds the radially outer winding edges (19-21).

7. A winding arrangement according to claim 1 or 2, wherein: the shielding elements (62-64; 23, 24) each have a shielding device (83, 91) for field guidance in the region of their ends.

8. A winding arrangement according to claim 1 or 2, wherein: the winding arrangement is contained within an electrically conductive container (26, 66).

9. A winding arrangement according to claim 1 or 2, wherein: the windings (1, 2; 34, 37, 35, 36) each surround a core limb (67; 68) of a transformer core (25, 69).