EP4600981A1 - Transformer spacer, manufacturing method and transformer - Google Patents

Transformer spacer, manufacturing method and transformer

Info

Publication number
EP4600981A1
EP4600981A1 EP24157046.4A EP24157046A EP4600981A1 EP 4600981 A1 EP4600981 A1 EP 4600981A1 EP 24157046 A EP24157046 A EP 24157046A EP 4600981 A1 EP4600981 A1 EP 4600981A1
Authority
EP
European Patent Office
Prior art keywords
spacer
region
regions
spacers
transformer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24157046.4A
Other languages
German (de)
French (fr)
Inventor
Robert Sekula
Grzegorz Kmita
Janusz Sadowski
Michal Kozupa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Energy Ltd
Original Assignee
Hitachi Energy Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Energy Ltd filed Critical Hitachi Energy Ltd
Priority to EP24157046.4A priority Critical patent/EP4600981A1/en
Priority to PCT/EP2025/052249 priority patent/WO2025172054A1/en
Publication of EP4600981A1 publication Critical patent/EP4600981A1/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/30—Fastening or clamping coils, windings, or parts thereof together; Fastening or mounting coils or windings on core, casing, or other support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/322—Insulating of coils, windings, or parts thereof the insulation forming channels for circulation of the fluid
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • H01F27/10—Liquid cooling
    • H01F27/12—Oil cooling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/33—Arrangements for noise damping

Definitions

  • a spacer for a voltage transformer is provided. Further a manufacturing method for such a spacer is provided. Moreover, a transformer using such spacers is also provided.
  • a problem to be solved is to provide a transformer with improved properties.
  • the spacer is for a transformer, like a high-voltage transformer and/ or a power transformer, and comprises a first material which is a polymer.
  • the spacer is of sheet-shape.
  • the spacer comprises a first region and a second region, the first region has a higher modulus of elasticity than the second region.
  • the spacer there are two different kinds of regions, that is, the first region or also a plurality of the first regions having a first, higher modulus of elasticity and there is the second region or a plurality of the second regions having a second, lower modulus of elasticity.
  • the at least one first region and the at least one second region differ in their mechanical properties, like elasticity, hardness and/or damping against vibrations. It is possible that the spacer consists of the first and second regions.
  • all the first regions have the same modulus of elasticity.
  • all the first regions if there is a plurality of the first regions, are made of the same material and having the same fill factor and, if present, the same internal geometric structuring.
  • the first region or all the first regions may be one or a plurality of massive regions of the first material.
  • the at least one first region and the at least one second region may be in direct contact with each other. Hence, the first and the second regions may touch. Hence, there may be no intermediate space between the first and second regions despite, for example, a connection means like a glue.
  • That the spacer is of rod-shape may mean, for example, that a length L of the spacer exceeds a mean diameter D by at least a factor of five or by at least a factor of ten or by at least a factor of 20.
  • the cross-section may be in a plane normal to a length direction of the spacer.
  • the modulus of elasticity refers to at least one of the Young's modulus, the shear modulus, the bulk modulus, the flexural modulus or the hardness of the respective material. Unless specified otherwise below, the stated moduli of elasticity refer to room temperature, that is, 295 K.
  • radial spacers are one of the key insulating components of a typical disk winding of an oil-filled transformer.
  • the spacers are placed inside the transformer winding to ensure the distance between the individual winding disks.
  • the spacers carry considerable mechanical loads resulting from the weight and initial compression of the winding and vibrations during its operation.
  • the spacers must withstand extremely large fast-changing loads caused by electrodynamic forces in the event of a short circuit.
  • radial spacers must have satisfactory dielectric properties, be chemically and mechanically resistant in a wide range of transformer operating temperatures, especially at elevated temperatures, including high resistance to insulating oil and low ability to absorb moisture.
  • Pressboard is traditionally used for the production of radial spacers due to its excellent electrical properties, good long-term performance and relatively low cost.
  • Pressboard is used in nearly all types of transformers, from small distribution transformers to large power transformers.
  • the spacers are manufactured as single-material or multi-material, single-layered or multi-layered and multi-functional structures, that is, for example, with a solid or lattice-like rigid core for mechanical stability and with a softer outer layer for noise attenuation, using, for example, an extrusion process like co-extrusion, a molding process like two-component injection molding, a printing method like multi-material 3D printing and/or a laminating process or coating.
  • a multi-material transformer winding spacer is manufactured by the method described herein.
  • the first region, some of the first region or all of the first regions have a higher fill factor than the second region, some of the second regions or all of the second regions.
  • the fill factor is the proportion of the respective volume filled with a solid material composition.
  • the fill factor of the at least one first region is one or virtually one. That is, the at least one first region can be free of holes or voids and may be a massive part of the spacer. Contrary to that, in the second region there may be voids or holes.
  • the term void or hole may refer to an evacuated, gas-filled or liquid-filled area of the spacer.
  • the fill factor in the at least one second region is at least 0.01 or is at least 0.1 or is at least 0.2.
  • the fill factor in the at least one second region is at most 0.9 or is at most 0.8 or is at most 0.7.
  • the fill factor is below one so that there are voids.
  • the fill factor may be at most 0.95 or at most 0.85 in the at least one first region.
  • both the first and second regions are made of the same material, that is, of the first material.
  • the spacer may consist of the first material.
  • the first region is constructed of the first material and the second region is constructed of the second material.
  • the at least one first region consists of the first material or of the first material and the voids or of the first material, the voids and at least one additive.
  • the at least one second region can consist of the second material or of the second material and the voids or of the second material, the voids and at least one further additive.
  • the second material can have a lower modulus of elasticity than the first material.
  • the first and second regions can be massive regions, that is, with a fill factor of one.
  • both the first and second regions can be free of voids.
  • the first material is or comprises at least one of a polyetherimide, PEI, polyphthalamide, PPA, or a polyphenylene sulfide, PPS.
  • the second material is or comprises at least one of a siloxane, like a silicone, a silicone rubber, a fluorosilicone, a nitrile rubber, a fluorocarbon rubber, ethylene propylene rubber, EPR/EPDM, or a polyurethane, PU.
  • a siloxane like a silicone, a silicone rubber, a fluorosilicone, a nitrile rubber, a fluorocarbon rubber, ethylene propylene rubber, EPR/EPDM, or a polyurethane, PU.
  • the spacer can damp acoustic noise, especially in the frequency range between 100 Hz and 250 Hz.
  • a noise reduction in this frequency range by at least 5 dB(A) or by at least 10 dB(A) may be achievable.
  • the moduli of elasticity refer to Young's moduli, shear moduli, bulk moduli or flexural moduli
  • said difference may be at least 2 MPa or at least 10 MPa or at least 30 MPa.
  • said difference may be at most 10 GPa or at most 15 GPa.
  • the first region or one, some or all of the first regions have the shape a plane-parallel sheet. It is possible that said sheet predominantly or completely extending across the spacer in a main plane of the spacer.
  • the main plain may be perpendicular to a height direction of the spacer and/or of said plane-parallel sheet. It is possible that the overall spacer is a plane-parallel sheet as well.
  • the first region is a core of the spacer and at least one second region is a hull, or vice versa.
  • the hull partially or completely covers the core.
  • the hull is applied on one or two main sides of the core.
  • one or some or all of narrow sides of the core are also covered with the hull.
  • the spacer comprises a plurality of the first regions and a plurality of the second regions.
  • the first and second regions are arranged in an alternating manner.
  • the first and second regions can form a stack. It is possible that the first and second regions alternate along the height direction. Otherwise, the first and second regions may alternate along a length direction and/or along a width direction, that is, in a lateral direction.
  • the second region or one or some or all of the second regions are applied as one or more stripes on the first region or, if there is a plurality of the first regions, on an outermost one of the first regions or on the two outermost first regions.
  • the stipe or the stripes are made of the second material which is applied on the first material.
  • the second region may be made of an internal geometric structuring constructed by the first material and being present on, for example, a massive body of the first material.
  • a proportion of the second region or all the second regions on the overall spacer is at least 1% by volume or is at least 10% by volume or is at least 20% by volume. Alternatively or additionally, said proportion is at most 60% by volume or is at most 40% by volume or is at most 20% by volume or is at most 10% by volume. Said proportion could be between 1% and 10% by volume in case of, for example, thin layers of the second material, or could be between 10% and 40% by volume in case of, for example, a geometric structuring being the at least one second region.
  • the second region or one or some or all of the second regions comprise a geometric structuring.
  • the geometric structuring comprises one or more of the following structural elements: lateral channel, oblique channel, wall, column, honeycomb, lattice, foam, sponge, truss. It is possible that different kinds of structural elements are combined with each other, for example, a honeycomb structure with a plurality of channels.
  • the at least one second region comprising the geometric structuring is made of a solid material composition around voids defined by the structural elements.
  • the second material may be used instead.
  • the geometric structuring could also be a mixture of the first and second materials.
  • a volume proportion of the voids on said at least one second region having the geometric structuring is at least 1% or at least 50 or at least 10% or at least 20% by volume. Alternatively or additionally, said proportion may be at most 80% or at most 70% or at most 50% or at most 30% by volume.
  • the first region or the first regions are massive regions of the first material free of any voids and free of the second material while the second region or the second regions comprising the geometric structuring are made of the first material as well and comprising the voids and/or the second material.
  • the spacer can be produced by two-component injection molding, or may be produced by separately producing the first and second regions of the first and second materials by molding and joining them together by, for example, lamination.
  • the second region may be made of the first material and comprising the geometric structuring and could be produced by extrusion together with the first region as a massive region of the first material, and an optional, additional second region of the second material may be applied by subsequent coating, like spray coating.
  • a transformer is additionally provided.
  • the transformer can comprise a plurality of the spacers as indicated in connection with at least one of the above-stated embodiments. Features of the transformer are therefore also disclosed for the spacer as well as the manufacturing method and vice versa.
  • the transformer comprises a plurality of winding disks and a plurality of spacers.
  • the spacers are located between adjacent ones of the winding disks spacing them from one another.
  • the spacers protrude from the winding disks in an inward and/or outward direction.
  • the spacers only partially fill an intermediate space between the respective adjacent ones of the winding disks.
  • the winding disk may be composed of several loops of a conductor like a copper wire.
  • the low-voltage and high-voltage windings of the transformer may each be composed of a plurality of the winding disks.
  • the transformer further comprises a tank.
  • the tank is configured to be filled with a liquid, like transformer oil.
  • the tank is of a metal like a steel.
  • the transformer further comprises one or a plurality of axial spacers.
  • the spacers each comprise at least one recess or protrusion, and the spacers are aligned in rows, like vertical rows, by means of the axial spacers engaging into the recesses or being engaged by the protrusions.
  • the tank is filled with the transformer oil.
  • the spacers and the winding disks as well as the at least one axial spacer can be immersed in the transformer oil. It is possible that the spacers and the winding disks are completely submerged in the transformer oil.
  • Figure 1 illustrates an exemplary embodiment of a spacer 1 for a transformer 10.
  • the spacer 1 comprises a first region 21 having a first modulus of elasticity.
  • the first region 1 corresponds to a core 33 and is made of a first material 41.
  • the first material is a poly ether imide, PEI, or a polyphenylene sulfide, PPS.
  • the spacer 1 comprises two second regions 22 with a lower, second modulus of elasticity.
  • the second regions 22 are of a second material 42.
  • the second material 42 is a siloxane or a polyurethane, PU.
  • the two second regions 22 have a same thickness along a height direction y. All the first and second regions 21, 22 may be plane-parallel sheets in direct contact with each other.
  • the overall spacer 1 can be a plane-parallel sheet as well.
  • the spacer 1 cannot only be of sheet-shape but may alternatively be of rod-shape, for example.
  • the first region 21 has a proportion of at least 50% or of at least 70% or of at least 85% of the spacer 1 along the height direction y. It is possible that said proportion is at most 98% or is at most 90%.
  • the two second regions 22 can be relatively thin.
  • a distance between winding disks 11 of the transformer 10, compare Figure 14 can be defined with high accuracy, while by means of the second regions 22 an acoustic damping and/or improved adhesion of the respective winding disks 11 at the spacer 1 can be achieved.
  • the thickness of the spacer 1 along the height direction y is at least 1 mm or is at least 5 mm. Alternatively or additionally, said thickness is at most 5 cm or is at most 2 cm. Further, a length along a length direction x and/or a width along a width direction z could be at least 1 cm or at least 5 cm; alternatively or additionally, said width and/or length could be at most 0.5 m or at most 0.3 m.
  • a thickness of the first region 21 is the same prior and after mounting the spacer 1 in the transformer 10, for example, with a tolerance of at most 50 or of at most 1% or of at most 0.2%.
  • the first region 21 is possibly not affected by being mounted in the transformer 10.
  • the second regions 22 it is possible that the thickness is greatly reduced upon being mounted in the transformer 10, for example, by at least 10% or by at least 20% or also by at least 60%. It may thus be possible that the second regions 22 become very thin when being mounted so that the winding disks 11 might be pressed into the second regions 22.
  • the first region 21 is subject to elastic deformation only while the second regions 22 may either be deformed elastically, too, or may be deformed plastically when being mounted in the transformer 10.
  • spacers 1 of the at least one polymer material 41, 42 pressboard spacers can be avoided.
  • regions 21, 22 with the different moduli of elasticity noise especially in the frequency range from 100 Hz to 240 Hz can significantly be reduced.
  • FIG. 2 there is a stack 36 of alternating first and second regions 22.
  • a top surface 20 and a bottom surface 24 of the spacer 1 are made of outermost second regions 22.
  • a number of the second regions 22 is a number of the first regions 21 plus one.
  • the spacer 1 can be of cubic shape.
  • the spacer 1 is a massive block free or virtually free of any voids.
  • the at least one second region 22 located between two adjacent ones of the first regions 21 can be of a different material composition compared with the outermost second regions 22.
  • the outermost second regions 22 have a lower modulus of elasticity than the at least one interior second region 22.
  • the spacer has also a second recess 52 opposite the first recess 51.
  • the two recesses 51, 52 may be of the same or of different shape, seen, for example, in top view of the top surface 20.
  • Such a second recess 52 can be present in all other embodiments, too.
  • one or two of the recesses 51, 52, if present, is/are replaced by a protrusion or by a plurality of protrusions.
  • the spacer 1 may engage with an axial spacer 14, compare Figure 14 .
  • the bottom surface 24 is made of the first region 21, or there are two of the second regions 22 as in Figures 1 or 2 , for example.
  • the first region 21 may have a plurality of indentations 39.
  • the indentations 39 By means of the indentations 39, a mechanical interconnection between the regions 21, 22 can be strengthened. If there is a second region on the bottom surface 24, too, then there can be indentations 39 towards the bottom surface 24 as well.
  • the second region 22 is a combination of the geometric structuring and using the second material 42 having the lower modulus of elasticity.
  • the second material 42 is applied on a main side of a massive body of the first material 41 as the first region 21.
  • the second material 42 is present only in places on said main side.
  • the second material 42 is applied in the shape of parallel stripes 35 extending along the length direction x.
  • a fill factor of said main side of the first region 21 is at least 10% or 20% and/or is at most 80% or 60%.
  • a relative proportion of the stripes 35 on an overall height of the spacer 1 along the thickness direction y is, for example, at least 5% and/or at most 30%.
  • the stripes 35 have a rectangular shape. However, other shapes like semi-circles, trapezoids, triangles or the like are also possible. Other than shown, the stripes 35 of the second material 42 can optionally also be present on the bottom surface 24. As described in connection with Figures 2 and 3 , recesses and/or protrusions can likewise be present as an option.
  • the spacer 1 is a void-free massive block of solid material.
  • the first material 41 is a matrix 32 for the second material 42.
  • the matrix 32 serves as the first region 21.
  • the second material 42 can be mixed into the first material 41 wherein the second material 42 preferably does not dissolve but maintains the form of particles, for example.
  • the additive 43 is an inorganic material like silicon dioxide and may have the form of particles mixed, for example, in the first material 41.
  • the spacer 1 is free of any additive and, thus, consists of the first and second materials 41, 42.
  • a volume proportion of the second material 42 is, for example, below 30%. Hence, the second material 42 can have a proportion below a percolation threshold. Otherwise, the volume proportion of the second material 42 may be above the percolation threshold. The same applies for the at least one optional additive 43.
  • the stripes 35 may narrow in a direction away from the first region 21 which forms the core 33.
  • the stripes 35 are of round shape or of trapezoidal shape, seen in cross section, compare Figure 6 , left side and right side, respectively.
  • both the geometric structuring and the second material 42 can be present in the second region 22.
  • the geometric structuring is like in Figure 6 wherein a possible different shape for the geometric structuring is illustrated, that is, triangular stripes 35.
  • the second material 42 may either completely cover the geometric structuring, see Figure 7 , left side, or the second material 42 does not cover tips of the geometric structuring.
  • mixtures of the designs of Figures 4 and 6 are also possible, that is, stripes of the first material 41 alternating with stripes of the second material 42 wherein the stripes of the different materials may either touch or may be distant from one another.
  • dots or dashed lines of the geometric structuring and/or of the second material 42 may be applied in a regular grid, like a hexagonal or rectangular pattern, or may also be present in a random manner.
  • channels 37 as the geometric structuring and, thus, as the second region 22.
  • the channels 37 may run in a straight manner from the top surface 20 to the bottom surface 24 of the spacer 1 and can thus be through holes. Otherwise, the channels 37 can run in a bent or kinked manner.
  • channels 37 instead of channels 37 as through holes it is possible to have blind holes or also a mixture of blind holes and through holes, not shown.
  • the channels 37 and/or blind holes can be arranged in a regular grid or also random, seen in top view of the top surface 20, for example. It is possible that the channels 37 and/or blind holes are arranged in blocks so that the channels 37 and/or blind holes are close with each other in the blocks with a larger, hole-free area between adjacent blocks, or the channels 37 and/or blind holes may be arranged in an equidistant manner. Seen in top view, the channels 37 and/or blind holes can be of round or polygonal shape, like circular, ellipsoidal, triangular, hexagonal or square, for example.
  • the channels 37 and/or blind holes are voids 38, that is, not filled with solid material.
  • the channels 37 and/or blind holes may be filled with a liquid, like transformer oil.
  • the channels 37 and/or blind holes can alternatively partly or completely be filled with the second material 42 wherein optionally there can be smaller voids in the second material 42.
  • the same as to the oblique channels 37 of Figure 8 may also apply to the longitudinal channels 37 of Figures 9 to 11 . That is, there can alternatively or additionally be blind holes and the channels 37 and/or blind holes may be bent or kinked or meandering, and the channels 37 and/or blind holes can have various cross-sectional shapes. Also various kinds of channels 37 having different shapes or diameters can be combined with each other. Again, instead of voids 38 the second material 42 can additionally or alternatively be present.
  • a geometric sub-structure can optionally be present, too, for example, having a honeycomb sub-structure.
  • Such substructures possibly allowing the flow of oil through the channels 37 but mechanically stabilizing the spacer 1 can also be present in all other embodiments having channels 37 and/or blind holes.
  • the channels 37 run between opposite front faces and, thus, reach the front faces. Contrary to that, the channels 37 may indeed be interior holes or arranged like a dash line within the spacer 1. Hence, the geometric structuring may completely be an internal structuring not reaching any surface of the spacer 1. This would correspond to Figure 10 , left side, if the drawing would be regarded a sectional view in the xy plane as well instead of a sectional view in the yz plane as shown.
  • Figure 11 it is shown that there can be a plurality of the layers of the channels 37, seen on the front face. As a further option it is illustrated in Figure 11 that there can be additional second regions 22, for example, by applying layers of the second material 42 or by having the geometric structuring as shown, for example, in connections with any one of Figures 4, 6 or 7 .
  • a manufacturing method for the spacer 1 is schematically shown.
  • a special tool for forming the spacer 1 is provided.
  • Such a tool can be, for example, a mold for a multi-component injection molding or an extrusion tool.
  • the axial spacers 14 are also made of the first material 41 and optionally of the second material 42 so that the axial spacers 14 may also comprise the first and second regions 21, 22.
  • the spacers 1 described in connection with Figures 1 to 12 could indeed be radial spacers or also axial spacers 14.
  • the spacers may not only be of sheet-shape but can be of rod-shape or also can be of other shapes.
  • the configuration of Figure 8 may particularly be suitable for an axial spacer 14 so that Figure 8 may schematically refer to an axial spacer; the same applies in principle for Figures 1 to 7 and 9 to 12 as well.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)

Abstract

In at least one embodiment, the spacer (1) is for a highvoltage transformer (10) and comprises a first material (41) which is a polymer. The spacer (1) is, for example, of sheetshape, and comprises a first region (21) and a second region (22), the first region (21) has a higher modulus of elasticity than the second region (22).

Description

  • A spacer for a voltage transformer is provided. Further a manufacturing method for such a spacer is provided. Moreover, a transformer using such spacers is also provided.
  • Document WO 2018/032269 A1 refers to an electrically insulating composite material.
  • Documents US 2011/0037551 A1 and US 2017/0321378 A1 disclose transformers.
  • Document C. Oria et al., "Degradation of the compression strength of spacers made of high-density pressboard used in power transformers under the influence of thermal ageing", Cellulose (2023) 30:6539-6558, https://doi.org/10.1007/s10570-023-05268-8, refers to pressboard spacers in transformers.
  • A problem to be solved is to provide a transformer with improved properties.
  • This object is achieved, inter alia, by a spacer, a manufacturing method and a transformer as defined in the independent claims. Exemplary further developments constitute the subject-matter of the dependent claims.
  • In at least one embodiment, the spacer is for a transformer, like a high-voltage transformer and/ or a power transformer, and comprises a first material which is a polymer. For example, the spacer is of sheet-shape. Moreover, the spacer comprises a first region and a second region, the first region has a higher modulus of elasticity than the second region.
  • Hence, in the spacer there are two different kinds of regions, that is, the first region or also a plurality of the first regions having a first, higher modulus of elasticity and there is the second region or a plurality of the second regions having a second, lower modulus of elasticity. Thus, the at least one first region and the at least one second region differ in their mechanical properties, like elasticity, hardness and/or damping against vibrations. It is possible that the spacer consists of the first and second regions.
  • Moreover, it is possible that there are different kinds of second regions, for example, having different moduli of elasticity being in each case lower than the modulus of elasticity of the first region or of the first regions.
  • It is further possible that all the first regions have the same modulus of elasticity. For example, all the first regions, if there is a plurality of the first regions, are made of the same material and having the same fill factor and, if present, the same internal geometric structuring. However, the first region or all the first regions may be one or a plurality of massive regions of the first material.
  • The at least one first region and the at least one second region may be in direct contact with each other. Hence, the first and the second regions may touch. Hence, there may be no intermediate space between the first and second regions despite, for example, a connection means like a glue.
  • If the spacer is a radial spacer, the spacer may be of sheet-shape. Otherwise, the spacer may be of rod-shape, for example, in case of being an axial spacer. Other shapes are also possible. That the spacer is of sheet-shape may mean, for example, that the spacer is flat. By way of example, for a thickness t of the spacer and its volume V it then applies t/V ≤ 0.03 m-2 or t/V ≤ 0.01 m-2 or t/V ≤ 0.003 m-2. In other words, the thickness t is small relative to a length and/or width of the spacer. That the spacer is of rod-shape may mean, for example, that a length L of the spacer exceeds a mean diameter D by at least a factor of five or by at least a factor of ten or by at least a factor of 20. For the mean diameter D and a cross-sectional area A of the spacer it applies, for example, D = (4 A/π)0.5, or it applies D = (V/L)0.5. The cross-section may be in a plane normal to a length direction of the spacer.
  • For example, the modulus of elasticity refers to at least one of the Young's modulus, the shear modulus, the bulk modulus, the flexural modulus or the hardness of the respective material. Unless specified otherwise below, the stated moduli of elasticity refer to room temperature, that is, 295 K.
  • Especially radial spacers are one of the key insulating components of a typical disk winding of an oil-filled transformer. The spacers are placed inside the transformer winding to ensure the distance between the individual winding disks. The spacers carry considerable mechanical loads resulting from the weight and initial compression of the winding and vibrations during its operation. In addition, the spacers must withstand extremely large fast-changing loads caused by electrodynamic forces in the event of a short circuit.
  • Moreover, radial spacers must have satisfactory dielectric properties, be chemically and mechanically resistant in a wide range of transformer operating temperatures, especially at elevated temperatures, including high resistance to insulating oil and low ability to absorb moisture.
  • Pressboard is traditionally used for the production of radial spacers due to its excellent electrical properties, good long-term performance and relatively low cost. Nowadays it is used in nearly all types of transformers, from small distribution transformers to large power transformers.
  • However, pressboard has some drawbacks related to the basic properties of cellulose, which limits the performance of the entire transformer and implies consequences in the transformer design and its manufacturing process. One of the main issues is the water adsorption by the cellulose from the moisture of the surrounding air, which negatively impacts the electrical properties and causes deformation of the spacer. Due to that, the pressboard must be dried after winding assembly and the winding is sized to obtain the desired shape. Such issues with deformations during drying make it challenging to properly estimate the height of the transformer winding within the desired tolerances.
  • In addition, the currently used pressboard spacers in contact with the winding do not make a significant contribution to reducing an audible noise generated in the winding, which is considered as one of the main environmental hazards generated by transformers.
  • The spacers described herein are made of one or of a combination of polymeric materials with different viscoelastic properties. The type of polymers, their thicknesses and final shape can be designed in such a way as to ensure noise damping functionality. For example, the body or core of the spacer is designed in the form of a lattice-like structure, which enables an enhanced oil flow and improves the cooling capability of the winding.
  • In the method described herein, the spacers are manufactured as single-material or multi-material, single-layered or multi-layered and multi-functional structures, that is, for example, with a solid or lattice-like rigid core for mechanical stability and with a softer outer layer for noise attenuation, using, for example, an extrusion process like co-extrusion, a molding process like two-component injection molding, a printing method like multi-material 3D printing and/or a laminating process or coating. For example, a multi-material transformer winding spacer is manufactured by the method described herein.
  • According to at least one embodiment, the first region, some of the first region or all of the first regions have a higher fill factor than the second region, some of the second regions or all of the second regions. For example, the fill factor is the proportion of the respective volume filled with a solid material composition.
  • It is possible that the fill factor of the at least one first region is one or virtually one. That is, the at least one first region can be free of holes or voids and may be a massive part of the spacer. Contrary to that, in the second region there may be voids or holes. The term void or hole may refer to an evacuated, gas-filled or liquid-filled area of the spacer.
  • For example, the fill factor in the at least one second region is at least 0.01 or is at least 0.1 or is at least 0.2. Alternatively or additionally, the fill factor in the at least one second region is at most 0.9 or is at most 0.8 or is at most 0.7. However, it is possible that in both the first and second regions the fill factor is below one so that there are voids. For example, the fill factor may be at most 0.95 or at most 0.85 in the at least one first region.
  • In case of different fill factors of the first and second regions, it is possible that both the first and second regions are made of the same material, that is, of the first material. Thus, the spacer may consist of the first material.
  • According to at least one embodiment, the spacer further comprises a second material different from the first material. It is possible that the second material is a polymer as well.
  • According to at least one embodiment, the first region is constructed of the first material and the second region is constructed of the second material. This means, for example, that the at least one first region consists of the first material or of the first material and the voids or of the first material, the voids and at least one additive. Correspondingly, the at least one second region can consist of the second material or of the second material and the voids or of the second material, the voids and at least one further additive. Hence, the second material can have a lower modulus of elasticity than the first material.
  • In this case, the first and second regions can be massive regions, that is, with a fill factor of one. Thus, both the first and second regions can be free of voids.
  • According to at least one embodiment, the first material is or comprises at least one of a polyetherimide, PEI, polyphthalamide, PPA, or a polyphenylene sulfide, PPS.
  • According to at least one embodiment, the second material is or comprises at least one of a siloxane, like a silicone, a silicone rubber, a fluorosilicone, a nitrile rubber, a fluorocarbon rubber, ethylene propylene rubber, EPR/EPDM, or a polyurethane, PU.
  • Hence, the spacer can be used in transformer oil. By using such materials, the spacer can have a low dielectric constant or relative permittivity of, for example, at most 4.4. A dielectric withstand of at least 20 kV/mm can be achieved by using such materials in the spacer. In addition, the spacer can withstand elevated temperatures, for example, the spacer can be used at a long-lasting temperature of 110 °C like in a transformer and may withstand elevated temperatures of, for example, 140 °C for short times below 10 min or the like.
  • Furthermore, by using such materials and structures the spacer can damp acoustic noise, especially in the frequency range between 100 Hz and 250 Hz. Compared with pressboard spacers, a noise reduction in this frequency range by at least 5 dB(A) or by at least 10 dB(A) may be achievable.
  • According to at least one embodiment, the moduli of elasticity of the first material and of the second material differ by at least a factor of 1.5 or by at least a factor of 2.0 or by at least a factor of 3. Alternatively or additionally, said difference is at most a factor of 50 or at most a factor of 10 or at most a factor of 5.
  • For example, if the moduli of elasticity refer to Young's moduli, shear moduli, bulk moduli or flexural moduli, said difference may be at least 2 MPa or at least 10 MPa or at least 30 MPa. Alternatively or additionally, said difference may be at most 10 GPa or at most 15 GPa.
  • According to at least one embodiment, the first material is a matrix in which the second material is distributed. Otherwise, the second material may be a matrix in which the first material is distributed. This may apply to one or some or all of the first and second regions. For example, the second material is in the form of particles or bubbles mixed into the first material, or vice versa. The distribution of the one material in the other one may be random or regular. For example, the mixture of the two materials may form a regular grid, a glass-like structure having a short-range order but no long-range order.
  • According to at least one embodiment, the first region or one, some or all of the first regions have the shape a plane-parallel sheet. It is possible that said sheet predominantly or completely extending across the spacer in a main plane of the spacer. The main plain may be perpendicular to a height direction of the spacer and/or of said plane-parallel sheet. It is possible that the overall spacer is a plane-parallel sheet as well.
  • According to at least one embodiment, the first region is a core of the spacer and at least one second region is a hull, or vice versa. The hull partially or completely covers the core. For example, the hull is applied on one or two main sides of the core. Optionally, one or some or all of narrow sides of the core are also covered with the hull.
  • For example, the core is of the first material and the hull is of the second material so that the core corresponds to the first region. It is also possible that both the hull and the core are of the first material wherein the core has a lower fill factor so that the core may correspond to the second region.
  • According to at least one embodiment, the spacer comprises a plurality of the first regions and a plurality of the second regions. For example, the first and second regions are arranged in an alternating manner. Hence, the first and second regions can form a stack. It is possible that the first and second regions alternate along the height direction. Otherwise, the first and second regions may alternate along a length direction and/or along a width direction, that is, in a lateral direction.
  • According to at least one embodiment, the second region or one or some or all of the second regions are applied as one or more stripes on the first region or, if there is a plurality of the first regions, on an outermost one of the first regions or on the two outermost first regions. For example, the stipe or the stripes are made of the second material which is applied on the first material. Otherwise, the second region may be made of an internal geometric structuring constructed by the first material and being present on, for example, a massive body of the first material.
  • According to at least one embodiment, a proportion of the second region or all the second regions on the overall spacer is at least 1% by volume or is at least 10% by volume or is at least 20% by volume. Alternatively or additionally, said proportion is at most 60% by volume or is at most 40% by volume or is at most 20% by volume or is at most 10% by volume. Said proportion could be between 1% and 10% by volume in case of, for example, thin layers of the second material, or could be between 10% and 40% by volume in case of, for example, a geometric structuring being the at least one second region.
  • According to at least one embodiment, the second region or one or some or all of the second regions comprise a geometric structuring. For example, the geometric structuring comprises one or more of the following structural elements: lateral channel, oblique channel, wall, column, honeycomb, lattice, foam, sponge, truss. It is possible that different kinds of structural elements are combined with each other, for example, a honeycomb structure with a plurality of channels.
  • According to at least one embodiment, the at least one second region comprising the geometric structuring is made of a solid material composition around voids defined by the structural elements. Instead of gas-filled or liquid-filled voids, the second material may be used instead. Hence, the geometric structuring could also be a mixture of the first and second materials.
  • According to at least one embodiment, a volume proportion of the voids on said at least one second region having the geometric structuring is at least 1% or at least 50 or at least 10% or at least 20% by volume. Alternatively or additionally, said proportion may be at most 80% or at most 70% or at most 50% or at most 30% by volume.
  • For example, the first region or the first regions are massive regions of the first material free of any voids and free of the second material while the second region or the second regions comprising the geometric structuring are made of the first material as well and comprising the voids and/or the second material.
  • A method for manufacturing the spacer is additionally provided. By means of the method, a spacer can be produced as indicated in connection with at least one of the above-stated embodiments. Features of the spacer are therefore also disclosed for the method and vice versa.
  • In at least one embodiment, the manufacturing method is for producing a spacer and comprises:
    Forming the first region and the second region by at least one of an extrusion process like multi-material co-extrusion, a molding process like one-component injection molding or multi-component injection molding, a printing process like single-material 3D printing or multi-material 3D printing, a coating process like using a doctor blade, 2D printing, dip coating or spray coating and/or by a connecting process like lamination, gluing or welding.
  • For example, if the spacer is made of the first and the second material, the spacer can be produced by two-component injection molding, or may be produced by separately producing the first and second regions of the first and second materials by molding and joining them together by, for example, lamination. In another example, the second region may be made of the first material and comprising the geometric structuring and could be produced by extrusion together with the first region as a massive region of the first material, and an optional, additional second region of the second material may be applied by subsequent coating, like spray coating.
  • A transformer is additionally provided. The transformer can comprise a plurality of the spacers as indicated in connection with at least one of the above-stated embodiments. Features of the transformer are therefore also disclosed for the spacer as well as the manufacturing method and vice versa.
  • In at least one embodiment, the transformer comprises a plurality of winding disks and a plurality of spacers. The spacers are located between adjacent ones of the winding disks spacing them from one another. Optionally, the spacers protrude from the winding disks in an inward and/or outward direction. Optionally, the spacers only partially fill an intermediate space between the respective adjacent ones of the winding disks.
  • The winding disk may be composed of several loops of a conductor like a copper wire. The low-voltage and high-voltage windings of the transformer may each be composed of a plurality of the winding disks.
  • According to at least one embodiment, the transformer further comprises a tank. The tank is configured to be filled with a liquid, like transformer oil. For example, the tank is of a metal like a steel.
  • According to at least one embodiment, the transformer further comprises one or a plurality of axial spacers. For example, the spacers each comprise at least one recess or protrusion, and the spacers are aligned in rows, like vertical rows, by means of the axial spacers engaging into the recesses or being engaged by the protrusions.
  • According to at least one embodiment, the tank is filled with the transformer oil. Hence, the spacers and the winding disks as well as the at least one axial spacer can be immersed in the transformer oil. It is possible that the spacers and the winding disks are completely submerged in the transformer oil.
  • For example, the transformer is configured for a voltage of at least 10 kV or of at least 20 kV or of at least 100 kV. Said voltage may refer to a high-voltage end of the transformer. Thus, the transformer could be a high-power transformer which may mean that the transformer is configured for currents at the low-voltage side of at least 0.1 kA or at least 1 kA or at least 10 kA. That the transformer is configured for these values may mean that the thicknesses of insulation materials and distances between current-conducting parts are so that the above voltages can be carried and that diameters of current-conducting parts are fitted to carry the electric currents specified above.
  • A spacer, a transformer and a manufacturing method described herein are explained in greater detail below by way of exemplary embodiments with reference to the drawings. Elements which are the same in the individual figures are indicated with the same reference numerals. The relationships between the elements are not shown to scale, however, but rather individual elements may be shown exaggeratedly large to assist in understanding.
  • In the figures:
    • Figures 1 to 5
    show schematic perspective views of exemplary embodiments of spacers described herein,
    Figures 6 and 7
    show schematic sectional views of exemplary embodiments of spacers described herein,
    Figures 8 and 9
    show schematic perspective views and sectional views of exemplary embodiments of spacers described herein,
    Figure 10
    shows schematic sectional views of exemplary embodiments of spacers described herein,
    Figure 11
    shows a schematic perspective views of an exemplary embodiment of a spacer described herein,
    Figure 12
    shows a schematic sectional view and a perspective view of an exemplary embodiment of a spacer described herein,
    Figure 13
    shows a schematic block diagram of an exemplary embodiment of a method for producing spacers described herein,
    Figure 14
    shows a schematic sectional views of an exemplary embodiment of a transformer comprising spacers described herein, and
    Figure 15
    shows a schematic detail in top view of the transformer of Figure 14.
  • Figure 1 illustrates an exemplary embodiment of a spacer 1 for a transformer 10. The spacer 1 comprises a first region 21 having a first modulus of elasticity. The first region 1 corresponds to a core 33 and is made of a first material 41. For example, the first material is a poly ether imide, PEI, or a polyphenylene sulfide, PPS.
  • Moreover, the spacer 1 comprises two second regions 22 with a lower, second modulus of elasticity. The second regions 22 are of a second material 42. For example, the second material 42 is a siloxane or a polyurethane, PU.
  • It is possible that the two second regions 22 have a same thickness along a height direction y. All the first and second regions 21, 22 may be plane-parallel sheets in direct contact with each other. Thus, the overall spacer 1 can be a plane-parallel sheet as well. However, the spacer 1 cannot only be of sheet-shape but may alternatively be of rod-shape, for example.
  • For example, the first region 21 has a proportion of at least 50% or of at least 70% or of at least 85% of the spacer 1 along the height direction y. It is possible that said proportion is at most 98% or is at most 90%. Thus, the two second regions 22 can be relatively thin.
  • For example, by means of the first region 21, that is, by the core 33, a distance between winding disks 11 of the transformer 10, compare Figure 14, can be defined with high accuracy, while by means of the second regions 22 an acoustic damping and/or improved adhesion of the respective winding disks 11 at the spacer 1 can be achieved.
  • As in all other embodiments, for example, the thickness of the spacer 1 along the height direction y is at least 1 mm or is at least 5 mm. Alternatively or additionally, said thickness is at most 5 cm or is at most 2 cm. Further, a length along a length direction x and/or a width along a width direction z could be at least 1 cm or at least 5 cm; alternatively or additionally, said width and/or length could be at most 0.5 m or at most 0.3 m.
  • By way of example, a thickness of the first region 21 is the same prior and after mounting the spacer 1 in the transformer 10, for example, with a tolerance of at most 50 or of at most 1% or of at most 0.2%. Hence, the first region 21 is possibly not affected by being mounted in the transformer 10. For the second regions 22 it is possible that the thickness is greatly reduced upon being mounted in the transformer 10, for example, by at least 10% or by at least 20% or also by at least 60%. It may thus be possible that the second regions 22 become very thin when being mounted so that the winding disks 11 might be pressed into the second regions 22.
  • For example, the first region 21 is subject to elastic deformation only while the second regions 22 may either be deformed elastically, too, or may be deformed plastically when being mounted in the transformer 10.
  • By using the spacers 1 of the at least one polymer material 41, 42, pressboard spacers can be avoided. Thus, no long-lasting drying of the winding required after installing the winding disks 11 and no shrinkage or winding compacting takes place upon drying. In addition, by having the regions 21, 22 with the different moduli of elasticity, noise especially in the frequency range from 100 Hz to 240 Hz can significantly be reduced.
  • In the embodiment of Figure 2, there is a stack 36 of alternating first and second regions 22. A top surface 20 and a bottom surface 24 of the spacer 1 are made of outermost second regions 22. Although in Figure 2 only two of the first regions 21 are shown, there can be more than two of the first regions 21, for example, at least five and/or at most 20 of the first regions 21. A number of the second regions 22 is a number of the first regions 21 plus one.
  • It is possible that all the first and second regions 21, 22 are congruent, seen in top view of the top surface 20. Hence, the spacer 1 can be of cubic shape. For example, the spacer 1 is a massive block free or virtually free of any voids.
  • As an option, as in all other embodiments, there can be a first recess 51 along the width direction z. The first recess 51 may be arranged symmetrically along the width direction z.
  • Further, optionally the at least one second region 22 located between two adjacent ones of the first regions 21 can be of a different material composition compared with the outermost second regions 22. For example, the outermost second regions 22 have a lower modulus of elasticity than the at least one interior second region 22.
  • Otherwise, the same as to Figure 1 may also apply to Figure 2, and vice versa.
  • In Figure 3 it is shown that the spacer has also a second recess 52 opposite the first recess 51. The two recesses 51, 52 may be of the same or of different shape, seen, for example, in top view of the top surface 20. Such a second recess 52 can be present in all other embodiments, too. Moreover, in all embodiments it is possible that one or two of the recesses 51, 52, if present, is/are replaced by a protrusion or by a plurality of protrusions. By means of the recesses 51, 52 and/or protrusions, no shown, the spacer 1 may engage with an axial spacer 14, compare Figure 14.
  • Optionally, the bottom surface 24 is made of the first region 21, or there are two of the second regions 22 as in Figures 1 or 2, for example.
  • As a further options, the first region 21 may have a plurality of indentations 39. By means of the indentations 39, a mechanical interconnection between the regions 21, 22 can be strengthened. If there is a second region on the bottom surface 24, too, then there can be indentations 39 towards the bottom surface 24 as well.
  • Otherwise, the same as to Figures 1 and 2 may also apply to Figure 3, and vice versa.
  • In the embodiment of Figure 4, the second region 22 is a combination of the geometric structuring and using the second material 42 having the lower modulus of elasticity. Thus, the second material 42 is applied on a main side of a massive body of the first material 41 as the first region 21. Thus, the second material 42 is present only in places on said main side.
  • For example, the second material 42 is applied in the shape of parallel stripes 35 extending along the length direction x. For example, a fill factor of said main side of the first region 21 is at least 10% or 20% and/or is at most 80% or 60%. A relative proportion of the stripes 35 on an overall height of the spacer 1 along the thickness direction y is, for example, at least 5% and/or at most 30%.
  • Seen in cross section, the stripes 35 have a rectangular shape. However, other shapes like semi-circles, trapezoids, triangles or the like are also possible. Other than shown, the stripes 35 of the second material 42 can optionally also be present on the bottom surface 24. As described in connection with Figures 2 and 3, recesses and/or protrusions can likewise be present as an option.
  • Otherwise, the same as to Figures 1 to 3 may also apply to Figure 4, and vice versa.
  • According to Figure 5, the spacer 1 is a void-free massive block of solid material. In this embodiment, the first material 41 is a matrix 32 for the second material 42. The matrix 32 serves as the first region 21. Hence, the second material 42 can be mixed into the first material 41 wherein the second material 42 preferably does not dissolve but maintains the form of particles, for example.
  • As a further option, there can be one or a plurality of additives 43. For example, the additive 43 is an inorganic material like silicon dioxide and may have the form of particles mixed, for example, in the first material 41. Such an additive 43 can also be present in all other embodiments, however, it is also possible that the spacer 1 is free of any additive and, thus, consists of the first and second materials 41, 42.
  • A volume proportion of the second material 42 is, for example, below 30%. Hence, the second material 42 can have a proportion below a percolation threshold. Otherwise, the volume proportion of the second material 42 may be above the percolation threshold. The same applies for the at least one optional additive 43.
  • The second material 42 may be distributed in the first material 41 in a random or in a regular manner.
  • It may also be possible that the first material 41 is distributed in the second material 42, opposite to what is shown in Figure 5; in this case, the same as above can apply analogously.
  • Otherwise, the same as to Figures 1 to 4 may also apply to Figure 5, and vice versa.
  • In Figure 6 it is illustrated that the spacer 1 is only of the first material 41, or of the first material 41 and the optional at least one additive 43. The second region 22 having the lower modulus of elasticity is thus realized by the geometric structuring. For example, the geometric structuring is done by having a plurality of the stripes 35 next to the top side 20 and optionally also next to the bottom side 24, indicated as a dash line in Figure 6.
  • Seen in cross section, the stripes 35 may narrow in a direction away from the first region 21 which forms the core 33. For example, the stripes 35 are of round shape or of trapezoidal shape, seen in cross section, compare Figure 6, left side and right side, respectively.
  • The stripes 35 may extend as straight lines next to the top side 20, for example, along the length direction x. However, also meandering or zigzag stripes are possible, not shown.
  • Otherwise, the same as to Figures 1 to 5 may also apply to Figure 6, and vice versa, especially the details on the geometric structuring as described in connection with Figure 4.
  • In Figure 7 it is shown again that both the geometric structuring and the second material 42 can be present in the second region 22. For example, the geometric structuring is like in Figure 6 wherein a possible different shape for the geometric structuring is illustrated, that is, triangular stripes 35. The second material 42 may either completely cover the geometric structuring, see Figure 7, left side, or the second material 42 does not cover tips of the geometric structuring. Further, mixtures of the designs of Figures 4 and 6 are also possible, that is, stripes of the first material 41 alternating with stripes of the second material 42 wherein the stripes of the different materials may either touch or may be distant from one another.
  • Optionally, such a second region 22 may also be present on the bottom surface 24. However, it is also possible to have different kinds of second regions 22 on the top surface 20 and on the bottom surface 24, as is possible in all other embodiments as well. For example, the second region 22 on the top side 20 is as shown in Figure 7 while the second region 22 on the bottom side 24 may just be a layer of the second material 42, similar to what is shown in Figure 1.
  • As in Figures 4 and 6, in context of Figure 7 it is possible that there are no stripes 35 but dots or dashed lines of the geometric structuring and/or of the second material 42. Such dots or short dashes, not shown, may be applied in a regular grid, like a hexagonal or rectangular pattern, or may also be present in a random manner.
  • Otherwise, the same as to Figures 1 to 6 may also apply to Figure 7, and vice versa.
  • In the embodiment of Figure 8, there are channels 37 as the geometric structuring and, thus, as the second region 22. The channels 37 may run in a straight manner from the top surface 20 to the bottom surface 24 of the spacer 1 and can thus be through holes. Otherwise, the channels 37 can run in a bent or kinked manner. Instead of channels 37 as through holes it is possible to have blind holes or also a mixture of blind holes and through holes, not shown.
  • The channels 37 and/or blind holes can be arranged in a regular grid or also random, seen in top view of the top surface 20, for example. It is possible that the channels 37 and/or blind holes are arranged in blocks so that the channels 37 and/or blind holes are close with each other in the blocks with a larger, hole-free area between adjacent blocks, or the channels 37 and/or blind holes may be arranged in an equidistant manner. Seen in top view, the channels 37 and/or blind holes can be of round or polygonal shape, like circular, ellipsoidal, triangular, hexagonal or square, for example.
  • According to Figure 8, the channels 37 and/or blind holes are voids 38, that is, not filled with solid material. Thus, when mounted in the transformer 1, the channels 37 and/or blind holes may be filled with a liquid, like transformer oil. Otherwise, the channels 37 and/or blind holes can alternatively partly or completely be filled with the second material 42 wherein optionally there can be smaller voids in the second material 42. Moreover, it is possible that there are different kinds of channels 37 and/or blind holes, for example, having different cross-sectional shapes, sizes and/or orientations relative to the top surface 20.
  • Otherwise, the same as to Figures 1 to 7 may also apply to Figure 8, and vice versa.
  • According to Figures 9 to 11, the geometric structuring of the second region 22 is in the form of longitudinal channels 37 along the length direction x. Thus, a flow of oil through the channels 37 can take place in the transformer 1 to improve cooling of the winding disks 11.
  • Otherwise, the same as to the oblique channels 37 of Figure 8 may also apply to the longitudinal channels 37 of Figures 9 to 11. That is, there can alternatively or additionally be blind holes and the channels 37 and/or blind holes may be bent or kinked or meandering, and the channels 37 and/or blind holes can have various cross-sectional shapes. Also various kinds of channels 37 having different shapes or diameters can be combined with each other. Again, instead of voids 38 the second material 42 can additionally or alternatively be present.
  • According to Figure 9, there is one layer of the channels 37 having a rectangular cross section.
  • In Figure 10 it is illustrated that in the channels 37 a geometric sub-structure can optionally be present, too, for example, having a honeycomb sub-structure. Such substructures possibly allowing the flow of oil through the channels 37 but mechanically stabilizing the spacer 1 can also be present in all other embodiments having channels 37 and/or blind holes.
  • Further, in Figure 10, right side, it is shown that the channels 37 can comprise the sub-structure extending in the longitudinal direction x while in Figure 10, left side, the sub-structure extends in the width direction y. Both patterns may be used simultaneously or alternatively.
  • According to Figure 10, the channels 37 run between opposite front faces and, thus, reach the front faces. Contrary to that, the channels 37 may indeed be interior holes or arranged like a dash line within the spacer 1. Hence, the geometric structuring may completely be an internal structuring not reaching any surface of the spacer 1. This would correspond to Figure 10, left side, if the drawing would be regarded a sectional view in the xy plane as well instead of a sectional view in the yz plane as shown.
  • In Figure 11 it is shown that there can be a plurality of the layers of the channels 37, seen on the front face. As a further option it is illustrated in Figure 11 that there can be additional second regions 22, for example, by applying layers of the second material 42 or by having the geometric structuring as shown, for example, in connections with any one of Figures 4, 6 or 7.
  • Otherwise, the same as to Figures 1 to 8 may also apply to Figures 9 to 11, and vice versa.
  • In Figure 12 it is illustrated that first region 21 may be surrounded all around by the second region 22 so that front faces can also be covered by the second region. This may apply, for example, to the embodiments of Figures 1 to 4, 6, 7 and 11. Thus, from outside the spacer 1 only the second region 22 may be seen. Otherwise, the first region 21 may be all around the second region 22; this could be possible, for example, in the embodiments of Figures 5, 8, 9, 10 and 11.
  • Otherwise, the same as to Figures 1 to 11 may also apply to Figure 12, and vice versa.
  • In Figure 13, a manufacturing method for the spacer 1 is schematically shown. In an optional methos step S1, a special tool for forming the spacer 1 is provided. Such a tool can be, for example, a mold for a multi-component injection molding or an extrusion tool.
  • In method step S2, the spacer 1 is produced. This may be done in a single step, like 3D printing, multi-component molding or co-extrusion so that in a single step the spacer 1 is formed in an integral manner. Otherwise, the first and second regions 21, 22 can be fabricated separately from one another and can then be joined, for example, by lamination or welding. Further, it is possible that one kind of the regions, for example, the first regions 21, are formed and that afterwards the other kind of regions, for example, the second regions 22, are applied; this may be done, for example, by means of a coating proceeding or a printing proceeding.
  • In the optional method step D3, the spacers 1 are then mounted in a transformer 10.
  • Otherwise, the same as to Figures 1 to 12 may also apply to Figure 13, and vice versa.
  • In Figure 14, an embodiment of the transformer 1 is shown and Figure 15 illustrates a detailed view on some of the spacers 1. The transformer 1 comprises a plurality of the winding disks 11 which are spaced apart from one another in a well-defined manner by means of the spacers 1. The spacers 1 can be in direct contact with the adjacent winding disks 11. Thus, the spacer 1 can be radial spacers.
  • For example, by means of the winding disks 11 a first, low-voltage winding 15 and a second, high-voltage winding 16 are created. The windings 15, 16 could be around a core 17 of soft iron, for example. The spacers 1 may be present in only one of the windings 15, 16, for example, in the first winding 15, or preferably in both windings 15, 16. The windings 15, 16 can be separated from one another by axial spacers 14. The radial spacers 1 can be adjusted by having the axial spacers 14 engaging in the recesses 51, 52 of the radial spacers 14.
  • It is possible that the transformer 1 further comprises a tank 12 filled with transformer oil 13. Hence, the spacers 1, 14 can be submerged in transformer oil.
  • It is possible that the axial spacers 14 are also made of the first material 41 and optionally of the second material 42 so that the axial spacers 14 may also comprise the first and second regions 21, 22. Thus, the spacers 1 described in connection with Figures 1 to 12 could indeed be radial spacers or also axial spacers 14. Accordingly, the spacers may not only be of sheet-shape but can be of rod-shape or also can be of other shapes. For example, the configuration of Figure 8 may particularly be suitable for an axial spacer 14 so that Figure 8 may schematically refer to an axial spacer; the same applies in principle for Figures 1 to 7 and 9 to 12 as well.
  • Otherwise, the same as to Figures 1 to 13 may also apply to Figures 14 and 15, and vice versa.
  • The components shown in the figures follow, unless indicated otherwise, exemplarily in the specified sequence directly one on top of the other. Components which are not in contact in the figures are exemplarily spaced apart from one another. If lines are drawn parallel to one another, the corresponding surfaces may be oriented in parallel with one another. Likewise, unless indicated otherwise, the positions of the drawn components relative to one another are correctly reproduced in the figures.
  • The invention described here is not restricted by the description on the basis of the exemplary embodiments. Rather, the invention encompasses any new feature and also any combination of features, which includes in particular any combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.
    • List of Reference Signs
    • 1
    spacer
    20
    top surface
    21
    first region
    22
    second region
    24
    bottom surface
    3
    structuring
    31
    plane-parallel sheet
    32
    matrix
    33
    core
    34
    hull
    35
    stripe
    36
    stack
    37
    channel
    38
    void
    39
    indentation
    41
    first material
    42
    second material
    43
    additive
    51
    first recess
    52
    second recess
    10
    transformer
    11
    winding disk
    12
    tank
    13
    transformer oil
    14
    axial spacer
    15
    first, low-voltage winding
    16
    second, high-voltage winding
    17
    transformer core
    S..
    method step
    xyz
    directions

Claims (15)

  1. A spacer (1) for a voltage transformer (10), which
    - comprises a first material (41) which is a polymer,
    - is of sheet-shape, and
    - comprises a first region (21) and a second region (22), the first region (21) has a higher modulus of elasticity than the second region (22).
  2. The spacer (1) according to the preceding claim,
    wherein the first region (21) has a higher fill factor than the second region (22).
  3. The spacer (1) according to any one of the preceding claims,
    further comprising a second material (42) different from the first material (41), the second material (42) being polymeric,
    wherein the second material (42) has a lower modulus of elasticity than the first material (41), and
    wherein the first region (21) is constructed of the first material (41) and the second region (22) is constructed of the second material (42).
  4. The spacer (1) according to the preceding claim,
    wherein the first material (41) comprises at least one of a polyetherimide, PEI, polyphthalamide, PPA, or a polyphenylene sulfide, PPS, and
    wherein the second material (42) comprises at least one of a a silicone, a silicone rubber, a fluorosilicone, a nitrile rubber, a fluorocarbon rubber, an ethylene propylene rubber, EPR/EPDM, or a polyurethane, PU.
  5. The spacer (1) according to any one of the two preceding claims,
    wherein the moduli of elasticity of the first material (41) and of the second material (42) differ by at least a factor of 1.5 and/or by at least 30 MPa.
  6. The spacer (1) according to any one of the three preceding claims,
    wherein the first material (41) is a matrix (32) in which the second material (42) is distributed.
  7. The spacer (1) according to any one of the preceding claims,
    wherein the first region (21) has the shape a plane-parallel sheet (31) completely extending across the spacer (1) in a main plane of the spacer (1).
  8. The spacer (1) according to any one of the preceding claims,
    wherein the first region (21) is a core (33) of the spacer (1) and the second region (22) is a hull (34) partially or completely covering the core (23).
  9. The spacer (1) according to any one of the preceding claims,
    comprising a plurality of the first regions (21) and of the second regions (22) arranged in an alternating manner in a stack (36).
  10. The spacer (1) according to any one of the preceding claims,
    comprising a further plurality of the second regions (22), said second regions (22) are applied as stripes (35) on the first region (21) or on an outermost one of the first regions (21) .
  11. The spacer (1) according to any one of the preceding claims,
    wherein a proportion of the second region (21) or all the second regions (21) on the spacer (1) is at least 1% by volume and is at most 60% by volume.
  12. The spacer (1) according to any one of the preceding claims,
    wherein the second region (22) or at least one of the second regions (22) comprises a geometric structuring comprising one or more of the following structural elements: lateral channel, oblique channel, wall, column, honeycomb, lattice, foam, sponge, truss,
    wherein said at least one second region (22) is made of a solid material composition (41, 42) around voids (38) defined by the structural elements, and
    wherein a volume proportion of the voids (38) on said at least one second region (22) is at least 1% by volume and at most 70% by volume.
  13. A manufacturing method for producing a spacer (1) of one of the preceding claims, comprising:
    forming the first region (21) and the second region (22) by at least one of a co-extrusion process, a one-component injection molding, a two-component injection molding, single-material 3D printing, multi-material 3D printing or lamination.
  14. A transformer (10) comprising
    - a plurality of winding disks (11),
    - a plurality of spacers (1) according to any one of claims 1 to 12,
    wherein
    - the spacers (1) are located between adjacent ones of the winding disks (11) spacing them from one another,
    - the spacers (1) protrude from the winding disks (11) in an inward and/or outward direction, and
    - the spacers (1) only partially fill an intermediate space between the respective adjacent ones of the winding disks (11) .
  15. The transformer (10) according to the preceding claim, further comprising a tank (12) and axial spacers (14),
    wherein the tank (12) is filled with transformer oil (13) so that the spacers (1) and the winding disks (11) are immersed in the transformer oil (13),
    wherein the transformer (10) is configured for a voltage of at least 10 kV,
    wherein the spacers (1) each comprise a recess (51, 52), the spacers (1) are align in vertical rows by means of the axial spacers (14) engaging into the recesses (51, 52).
EP24157046.4A 2024-02-12 2024-02-12 Transformer spacer, manufacturing method and transformer Pending EP4600981A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP24157046.4A EP4600981A1 (en) 2024-02-12 2024-02-12 Transformer spacer, manufacturing method and transformer
PCT/EP2025/052249 WO2025172054A1 (en) 2024-02-12 2025-01-29 Transformer spacer, manufacturing method and transformer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP24157046.4A EP4600981A1 (en) 2024-02-12 2024-02-12 Transformer spacer, manufacturing method and transformer

Publications (1)

Publication Number Publication Date
EP4600981A1 true EP4600981A1 (en) 2025-08-13

Family

ID=89900760

Family Applications (1)

Application Number Title Priority Date Filing Date
EP24157046.4A Pending EP4600981A1 (en) 2024-02-12 2024-02-12 Transformer spacer, manufacturing method and transformer

Country Status (2)

Country Link
EP (1) EP4600981A1 (en)
WO (1) WO2025172054A1 (en)

Citations (12)

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Publication number Priority date Publication date Assignee Title
JPH04306812A (en) * 1991-04-03 1992-10-29 Toshiba Corp stationary induction equipment
JPH065438A (en) * 1992-06-19 1994-01-14 Toshiba Corp Electrical equipment
JPH07320954A (en) * 1994-05-30 1995-12-08 Hitachi Ltd Stationary induction
JPH08191023A (en) * 1994-08-26 1996-07-23 Hitachi Ltd Resin molded coil, method of manufacturing resin molded coil, and transformer
JP2001006950A (en) * 1999-06-22 2001-01-12 Fuji Electric Co Ltd Induction winding
US20110037551A1 (en) 2005-09-29 2011-02-17 Abb Technology Ltd Oil Filled Transformer With Spacers and Spacers for Separating and Supporting Stacked Windings
JP2016033987A (en) * 2014-07-31 2016-03-10 株式会社東芝 Transformer
US20170321378A1 (en) 2014-10-20 2017-11-09 Abb Schweiz Ag Pressboard
WO2018032269A1 (en) 2016-08-15 2018-02-22 Abb Schweiz Ag Electrically insulating composite material and electrical product
US20180068758A1 (en) * 2015-03-17 2018-03-08 Abb Schweiz Ag Inorganic Electrical Insulation Material
JP6397504B2 (en) * 2014-10-17 2018-09-26 株式会社日立製作所 Transformer and high voltage generator
US20180330871A1 (en) * 2014-11-04 2018-11-15 Abb Schweiz Ag Transformer spacers

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04306812A (en) * 1991-04-03 1992-10-29 Toshiba Corp stationary induction equipment
JPH065438A (en) * 1992-06-19 1994-01-14 Toshiba Corp Electrical equipment
JPH07320954A (en) * 1994-05-30 1995-12-08 Hitachi Ltd Stationary induction
JPH08191023A (en) * 1994-08-26 1996-07-23 Hitachi Ltd Resin molded coil, method of manufacturing resin molded coil, and transformer
JP2001006950A (en) * 1999-06-22 2001-01-12 Fuji Electric Co Ltd Induction winding
US20110037551A1 (en) 2005-09-29 2011-02-17 Abb Technology Ltd Oil Filled Transformer With Spacers and Spacers for Separating and Supporting Stacked Windings
JP2016033987A (en) * 2014-07-31 2016-03-10 株式会社東芝 Transformer
JP6397504B2 (en) * 2014-10-17 2018-09-26 株式会社日立製作所 Transformer and high voltage generator
US20170321378A1 (en) 2014-10-20 2017-11-09 Abb Schweiz Ag Pressboard
US20180330871A1 (en) * 2014-11-04 2018-11-15 Abb Schweiz Ag Transformer spacers
US20180068758A1 (en) * 2015-03-17 2018-03-08 Abb Schweiz Ag Inorganic Electrical Insulation Material
WO2018032269A1 (en) 2016-08-15 2018-02-22 Abb Schweiz Ag Electrically insulating composite material and electrical product

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
C. ORIA ET AL.: "Degradation of the compression strength of spacers made of high-density pressboard used in power transformers under the influence of thermal ageing", CELLULOSE, vol. 30, 2023, pages 6539 - 6558, Retrieved from the Internet <URL:https://doi.org/10.1007/sl0570-023-05268-8>

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