EP4687160A1

EP4687160A1 - Coil arrangement, transformer and method

Info

Publication number: EP4687160A1
Application number: EP24199643.8A
Authority: EP
Inventors: Qingjun SUN; Yongjin Liu; Tianbing ZHENG
Original assignee: Hitachi Energy Ltd
Current assignee: Hitachi Energy Ltd
Priority date: 2024-07-31
Filing date: 2024-09-11
Publication date: 2026-02-04

Abstract

The invention relates to a coil arrangement for an electrical transformer (1) and comprisinga coil (20) made from cast resin and including a first coil member (31) and a second coil member (32), wherein the first and the second coil members (31, 32) each have an axial end face (30) with a recess (36), wherein the axial end faces (30) face one another;an elastic member (50) arranged between the axial end faces (30); anda pin member (60) having a first pin end (61) projecting into the recess (36) of the first coil member (31) and having a second pin end (62) projecting into the recess (36) of the second coil member (32).

Description

Technical Field

The invention relates to a coil arrangement for an electrical transformer, which coil arrangement comprises a coil including a first coil member and a second coil member, wherein the coil members have axial end faces facing one another. The invention furthermore relates to an electrical transformer with a coil arrangement and to a method.

Background Art

In electrical transformers, due to relatively large volume and weight, a coil of a coil arrangement may vibrate during operation. Additionally, dimensions of the coil may vary over time or depending on conditions in use. The coil including a first coil member and a second coil member, where their axial end faces face one another, exhibits the necessity to connect said coil members reliably to withstand vibration and change in dimensions while maintaining a long lifetime. Known solutions include connectors that grab around both coil members, which however necessitate an intricate manufacturing and assembly.
There is a desire to develop a coil arrangement that simplifies the assembly process while ensuring robust mechanical stability and optimal stress distribution. Such an arrangement would ideally include fewer components, be easier to manufacture, and offer enhanced stability and performance compared to existing designs.

Summary of invention

It is an object of the invention to provide solutions with respect to coil arrangements for electrical transformers that provide increased lifetime, lower cost to produce and an easier assembly. Particularly it is an object to avoid or reduce disadvantages of known solutions.
The object of the invention is solved by the features of the independent claims. Preferred implementations are detailed in the dependent claims, the description and the figures.
The object is particularly solved by a coil arrangement for an electrical transformer and comprising a coil made from cast resin (also referred to as 'resin cast coil'). The coil includes a first coil member and a second coil member, wherein the first and the second coil members each have an axial end face with a recess, wherein the axial end faces face one another. The coil arrangement comprises an elastic member arranged between the axial end faces, and a pin member having a first pin end projecting into the recess of the first coil member and having a second pin end projecting into the recess of the second coil member.
In other words, particularly, the present invention suggests a coil system for a dry-type transformer that includes a coil. The coil includes a first and a second coil section which are typically stacked atop one another with an elastic structure in between. End faces of the coil members between which the elastic structure is located have openings that are positioned to face each other. Additionally, at least one pin is provided engaging with the openings on both sides of the at least one pin.
By means of the invention and by means of aspects described in the present application, it is advantageously realized that a coil including two coil members (e.g. upper and lower coils) can be produced at lower cost while the engagement between them is enhanced. A cooling efficiency from convective air cooling through the coil may be enhanced due to the elastic member sealing a gap.
The invention provides that H-shaped blocks or connectors can be omitted which have been used in the past to grab around the axial end faces to provide a form fit therebetween, for example as shown in Fig. 6. The invention rather suggests that, especially instead of using such H-shaped blocks, the pin member can engage directly into the coil members, since respective recesses may be produced at little cost upon casting the coil members. The mechanical weakness of such H-shaped blocks or connectors is avoided and a gap may be reduced in size, enhancing cooling.
The first coil member may be securely locked by the pin member, offering an advantage over existing solutions. This type of mechanical locking typically requires smaller tolerances, ensuring a more precise and reliable fit.
The horizontal movement may initially be restricted by the friction of the elastic member, and eventually by the pin member. This dual mechanism provides a dependable fixation for the first coil member relative to the second coil member, enhancing stability and performance.
The overall height of the coil and thus of the coil arrangement or transformer can be reduced. This design change can lead to cost savings in production. The common problem of block cracking may be reduced or elimited based on the elastic member, ensuring a longer lifespan and improved durability of the components. The new design may be capable of withstanding the most critical vibration conditions, providing robust performance and reliability under challenging circumstances.
The coil may include two or more coil members, namely the first coil member and the second coil member and optionally more coil members. The coil members may be stacked atop each other to form the coil. The coil members may be made from cast resin. The coil members may have a substantially cylindrical shape. Each of the coil members may have the same size and/or diameter. The coil, particularly its coil members, may have an axial end face on each of two axially opposing sides, wherein the axial end faces may be arranged substantially in parallel to one another and/or may be substantially flat.
The first and the second coil members each have an axial end face with a recess, wherein the axial end faces with said recess may face one another. Thus, when the first and second coil members are stacked, the recesses can face one another, be adjacent to one another and/or align with one another in order to provide a form fit, e.g. via corresponding engagement means, e.g. via the pin member. The recesses may be formed as openings and/or blind holes in the respective axial end faces. The recesses may have a form or shape corresponding to the pin member. The recesses may have an at least sectionally round and/or flat shape. For example, the recesses may have the shape of a hemisphere and/or a concave shape.
The elastic member relates to a preferably monolithic and/or flexible structure. The elastic member is typically flat and particularly shaped to be placed between the coil members. The elastic member may comprise more than one piece. The elastic member may be referred to as a gasket and/or sealing mat.
The elastic member is arranged between the axial end faces of the two coil members. Thus, the elastic member is typically in contact to both of the two coil members, e.g. directly or indirectly, especially in terms of are. The elastic member may provide a distance between the coil members, transmit forces and provide a sealing of the transition between the two coil members.
The pin member or form fit member may be understood as a part configured for providing a form fit and/or for being inserted into a/the recess. The pin member may be understood as a part configured for provision of a form fit between two adjacent recesses. The pin member may have a solid structural shape, e.g. made in one piece or in two or more pieces that may be assembled. The pin member may have an at least sectionally symmetrical shape. The pin member may be at least sectionally round and/or cylindrically shaped. The pin member may be a ball or sphere or may exhibit at least sectionally a ball or sphere shape. Ends of the pin member may be round or flat. The pin member may be at least sectionally convex.
The pin member has a first pin end projecting into the recess of the first coil member and a second pin end projecting into the recess of the second coil member. The pin ends may be understood as different locations on the pin member. In particular, the pin ends are arranged on opposite sides of the pin member. Thus, the pin member may project on both of its opposite sides into the coil members. The pin member may project through and/or penetrate the elastic member.
Electrical transformers are known in the art. Transformers typically include a coil arrangement with at least one coil which coil can be supported by a coil block of the coil arrangement. Typical coil blocks can provide mechanical support of the coil and preferably electrical insulation. A longitudinal axis of the coil is typically arranged vertically. The coil can be supported by the coil block provided between an upper end of the coil and a support base, and between an upper end of the coil and another one of the support base. The coil blocks can provide the coil with sufficient stiffness to prevent vertical motion of the coil relative to the support bases. The transformer may be provided as a one, two or three phase transformer. Therefor, the transformer may comprise one, two or three coils or coil arrangements. The coil arrangement, particularly the transformer, may be configured for medium voltages and/or high voltages. The coil arrangement, particularly the transformer, may be configured to be used in electrical power distribution applications, for example in a distribution substation. The coil may have an outer diameter that is least 0.5 m and/or up to 1.5 m. The outer diameter particularly is at least 0.75 m and/or up to 1.25 m, particularly is 1.1 m ± 0.1 m. A length of the coil along an axial direction may be at least 0.5 m and/or up to 2 m. The coil may have a primary coil section and a secondary coil section inside the primary coil section. A wall may be arranged between said two coil sections. In an axial direction, the coil may comprise two or more separate coil members stacked atop each other which can form the coil.
The term high voltage means preferably a voltage above 12 kV or 36 kV or 72 kV or 1100 kV. A high voltage preferably relates to nominal voltages in the range from above 12 kV, 36 kV or 72 kV to 550 kV or 1100 kV, like 145 kV, 245 kV or 420 kV, or even more. The term medium voltage means preferably a voltage above 1 kV or 12 kV or 36 kV. A medium voltage preferably relates to nominal voltages in the range from above 1 kV, 12 kV or 36 kV to 72 kV, like 5 kV, 10 kV, 25 kV or 70 kV.
The coil is made from or includes cast resin, particularly is configured as a resin cast coil. The coil typically includes metallic windings which may be cast in epoxy resin. The coil may comprise the cast resin as a component of a composite material, e.g. the composite material including the cast resin and a fiber material embedded in the cast resin. The fiber material may be wound, e.g. arranged substantially in parallel to and/or substantially along the metallic windings.
The coil arrangement may have a support base. The support base is typically configured for supporting the coil. The support base may support the coil from at least one side. Supporting the coil may be understood in the sense of providing a foundation and/or a fixation. The support base may comprise a support beam. The support base may extend substantially obliquely or perpendicularly to an axial direction of the coil. The support base may support more than one coil, e.g. two or three coils which may be comprised by the coil arrangement.
The coil block can be arranged between the support base and the coil. The coil block may provide at least an indirect connection between the support base and the coil. The coil block may be in indirect or direct contact to the support base and/or the coil. The coil block may provide an electrical insulation for the coil relative to the ground. The coil block may comprise a substantially monolithic structure and/or a block shape. The block shape may comprise at least substantially a rigid and/or inflexible structure particularly configured for bearing loads along at least one direction. The coil block may have two support surfaces facing away from one another.
The coil block may comprise or consist of a fiber reinforced polymer compound and/or an electrically insulating material. The fiber reinforced polymer compound may include glass fibers and/or carbon fibers and/or a thermoset resin, wherein the fibers may be embedded in the thermoset resin. The coil block may be a monolithically shaped cast part. The coil block may comprise ribs extending substantially perpendicularly to the extension of the coil. Thus, electrical and/or mechanical properties of the coil arrangement may be enhanced. The coil block may as well be produced at low cost with enhanced lifetime.
The coil blocks may each comprise a primary support section for a primary coil side and a secondary support section for a secondary coil side, particularly the support sections extending axially with respect to the coil and arranged at a radial distance to each other with respect to the coil. If provided, the wall may extend between the two support sections. This dual-section design aims to ensure that both the primary and secondary coil sides of the coil are adequately supported while electrical properties can be adapted as required.
The pin member may have a substantially cylindrical shape and/or outer surface. The pin member may be sectionally convex and/or round. The pin member may extend between two pin ends. The pin member may have an at least substantially flat first pin end and particularly an at least substantially flat second pin end, which pin ends may be arranged substantially in parallel to one another. One or both ends or sides of the pin may have a chamfered and/or rounded edge. One or both ends or sides of the pin may be rounded and/or convex. The first and second pin end may exhibit substantially the same shape. This shape can simplify the assembly and may ensure a uniform distribution of stress along the pin member, enhancing the overall durability of the coil arrangement.
The recess of the first coil member and/or of the second coil member may be larger in cross-sectional area and/or in size or diameter relative to the pin member, e.g. by at least 1 % and/or up to 10 % or more. Said recess may correspond in shape to the pin member for the provision of a form fit. This design aims for for easier assembly and disassembly of the coil members.
The pin member may be made from an insulating material and/or a polymer compound, particularly comprising polyether ether ketone or PEEK for short. The pin member may include fiber material, e.g. glass fibers and/or carbon fibers. The pin member may be produced by means of casting to provide a relatively homogeneous material. The pin member may be configured with a thermal class assignment of at least 180 °C and/or with a compressive strength of at least 50 MPa. The thermal class assignment is preferably defined according to international standard IEC 60085:2007. This aims to ensure that the pin member can withstand high thermal and mechanical stresses, improving the performance and lifetime.
The pin member may have a diameter and the first coil member and/or the second coil member may have a thickness, especially wherein said thickness and diameter are to be seen in a radial direction of the coil. The diameter is preferably at least 20% and/or up to 80% of said thickness, particularly is at least 30% and/or up to 70%, more particularly is at least 40% and/or up to 60%. The pin member may have a/the diameter that is at least 20 mm and/or up to 80 mm, particularly is 50 mm ± 10 mm. The diameter should be smaller than the thickness. This proportion should optimize the mechanical stability of the coil arrangement.
The elastic member may be made from an electrically insulating material, particularly comprising rubber, a polymer compound and/or silicone. The elastic member may be produced in a casting or molding process. The elastic member may have a substantially uniform thickness. The elastic member may be configured as a flexible mat and/or gasket. This aims to enhance the assembly, the electrical insulation and the cooling properties of the coil arrangement.
The elastic member may be at least sectionally or fully ring-shaped, e.g. to follow the form of the axial end faces. Thus, the elastic member may have a central hole. The elastic member may be made as a single piece or may comprise multiple pieces, especially ring-shaped ones. This shape can provide a consistent and uniform compression distribution across the axial end faces, likely improving the mechanical stability and vibration dampening characteristics of the coil arrangement.
The elastic member may be in, especially direct, contact on opposite and particularly substantially parallel sides of the elastic member with the axial end faces, respectively. Thus, the elastic member may be located directly atop and adjacent to the first coil member and directly below and adjacent to the second coil member, especially providing a parallel arrangement of the two axial end faces. This should ensure that the elastic member maintains a stable and secure position, enhancing the overall reliability of the coil arrangement.
The elastic member may have an opening penetrated by the pin member. The opening is preferably as large as the pin member or larger for an easy assembly. The opening may be round or circular. The opening may extend from side to side of the elastic member, preferably substantially along the axial direction of the coil. This design may facilitate positioning of the elastic member onto the axial end face, ensuring precise alignment and stable mechanical connections between the coil members.
The coil arrangement may comprise two or more, particularly three or four, pin members. The pin members may be distributed along the axial end faces and/or in a circumferential direction. Each of the two or more pin members may engage with another one of the recesses in the first and the second coil member. This multiple pin arrangement aims to improve the mechanical stability and load distribution within the coil arrangement.
The first coil and the second coil each may comprise a primary coil side and a secondary coil side. Typically, the secondary coil side is arranged radially inside the primary coil side. Preferably, the recess is or the recesses are formed in the primary coil sides, respectively. The secondary coil side(s) may not necessarily exhibit recess(es).
The object is further solved by a dry-type transformer including the coil arrangement according to any one of the preceding claims, wherein the second coil member is configured for being arranged atop the first coil member. The dry-type transformer may comprise two or three of the coils, particularly arranged in a row.
The object is further solved by a method to produce one of the coil arrangement. The method comprises casting the first coil member and the second coil member, and afterwards placing the elastic member between the axial end faces and the pin member into the recesses. This method aims to ensure precise manufacturing and assembly of the coil arrangement, enhancing its mechanical and electrical performance. The coils may be produced at lower cost due to the fact that the recess can be produced by means of casting. The pin member may be casted as well.
The term 'or' may be replaced by 'and/or' throughout the present disclosure. As such, where 'or' is used, it is not necessarily meant that merely alternatives are named.

Brief description of drawings

These and other aspects of the invention will be apparent from and elucidated with reference to the implementations described hereinafter.
In the drawings:

Fig. 1 shows a part of a dry-type transformer in a perspective view;
Fig. 2 shows an elastic member to be arranged between axial end faces of the coil of Fig. 1;
Fig. 3 shows a pin member configured for projecting into recesses of the axial end faces of Fig. 1;
Fig. 4 shows a detail of the dry-type transformer of Fig. 1 in a perspective view;
Fig. 5A-B shows a first coil member of a coil (A) and the coil with the first coil member and a second coil member stacked atop each other (B) in a perspective view; and
Fig. 6 shows a detail of a dry-type transformer with H-shaped blocks connecting coil sections forming a coil in a perspective view.

Description of implementations

The description contains procedural or methodical aspects upon describing structural features of the invention; the structural features can be understood well in that way. It is emphasized to the reader that such structural features can be lifted from the described context without hesitation or the question of an intermediate generalization to form aspects of the invention. It is also emphasized to the reader that any the structural features described in the following can be understood as individual aspects of the invention to distinguish from known solutions, despite being possibly lifted from the context. The Figs. show schematic views, particularly not to scale.
Fig. 1 partially shows a dry-type transformer 1 including a coil arrangement 10 with three coils 20. The three coils 20 are made from or include cast resin (e.g. also known as cast resin coils). Each coil 10 is configured for each of three electrical phases the transformer 1 can be electrically coupled to. The coil arrangement 10 includes one support base 80 at the top and one support base 80 at the bottom. Each coil 20 stands on and engages with four coil blocks 70, which coil blocks 70 stand on and are coupled, e.g. bolted, to the support base 80 at the bottom. At the top, each coil 20 is supported via four coil blocks 70 which are coupled to the support base 80, e.g. bolted thereto. The support bases 80 comprise steel beams.
Particularly, the coil blocks 70 consist of an electrically insulating fiber reinforced polymer compound. The fiber reinforced polymer compound includes glass fibers or carbon fibers and a thermoset resin embedding the respective fibers.
The coils 20 include a radially inner secondary coil side 28 and an outer primary coil side 24 which are separated by a wall 26. The wall 26 is arranged radially between its primary side 24 and its secondary coil side. The wall 26 projects axially into the coil blocks 70, particularly into a support section or gap of the coil blocks 70. The wall 26 particularly extends in an axial direction on both sides beyond the coil sides 24, 28.
In an axial direction, each coil 20 comprises two separate coil members 31, 32 stacked atop each other forming the respective coil 20. For example, each coil 20 has, e.g. the coil members 31, 32 have, an outer diameter 22 of 1.1 m ± 0.1 m.
Here, the three coils 20 are arranged in a row. Between two adjacent coils 20 a partition wall 27 is arranged which can shield one coil 20 from the other coil 20. The partition wall 27 may be electrically insulating. The partition wall 27 may be fastened to one or to both support bases 80.
Fig. 1 shows the first coil member 31 and the second coil member 32 whose axial end faces 30 face one another. Particularly, the first 31 and the second 32 coil members each have the axial end face 30 formed with a recess (not shown in detail in Fig. 1). An elastic member 50 is arranged between the axial end faces 30. A thickness 51 of the elastic member 50 defines the size of a gap between the coil members 31, 32. The elastic member 50 is in contact on both axial sides to the axial end faces 30.
Fig. 2 shows the elastic member 50 that is arranged between the axial end faces 30 in Fig. 1. The elastic member 50 is made from an electrically insulating material, particularly comprising rubber and/or silicone. Thus, the elastic member 50 may seal the gap between the coil members 31, 32 by adaption to the axial end faces 30.
The elastic member 50 has a ring-shape. The elastic member 50 has four openings 52 distributed along the extension of the elastic member 50 and/or in a circumferential direction.
The openings 52 extend from one elastic member surface 54 to an opposite elastic member surface 54. The elastic member 50 is configured to be in contact on opposite sides of the elastic member 50 with the axial end faces 30, respectively. Particularly, the elastic member surfaces 54 are configured to be in contact to the axial end faces 30 of the coil 10 of Fig. 1.
The elastic member 50 has an inner diameter 56 that is at least 10 % smaller than an outer diameter 58. Particularly, half of the difference between the inner 56 and the outer 58 diameter substantially corresponds to a radial thickness of the coil members 31, 32, e.g. is equal or ± 25 % relative to said radial thickness. As an example, said radial thickness may be seen in Fig. 5A referenced by 34 and shown on a first coil member 31.
Particularly, the outer diameter 58 is substantially equal to the diameter 22 of the coil 20 (cf. Fig. 1) or less than that.
The elastic member 50 has a thickness 51 which is substantially uniform across the elastic member 50 between the elastic member surfaces 54.
Fig. 3 shows a pin member 60 of which has a substantially cylindrical shape. Four of the pin members 60 are arranged to project through and/or penetrate the openings 52 of the elastic member 50 of Fig. 2 so that pin ends 61, 62 are arranged on opposite sides of the openings 52.
The pin ends 61, 62 are configured to project into and/or penetrate the axial end faces 30 that face one another of the coil of Fig. 1. Particularly, the first pin end 61 of the pin members 60 is configured to project into a recess of the first coil member 31 and a second pin end 62 is configured to project into a recess of the second coil member 32 (not shown in detail in Figs. 1-3).
The pin members 60 exhibit a diameter 64 that is sized to fit into recesses of coil members 31, 32, particularly of their axial end faces 30. The diameter 64 is at least 20 mm, particularly the diameter 64 is at least or equal to 50 mm ± 10 mm. The pin members 60 may be configured for loosely fitting into a respective recess.
The pin members 60 exhibit a length 65 that is sized to partially fit into recesses of the coil members 31, 32, particularly of their axial end faces 30. The length 65 is at least 20 mm, particularly the length 65 is at least or equal to 50 mm ± 10 mm. For example, a depth of a respective recess may be less than half of the length 65 and particularly may be more than a tenth of the length 65.
The first pin end 61 and the second pin end 62 exhibit substantially flat pin end surfaces 66. Each pin end 61, 62 exhibits an edge 68. The edge 68 may be rounded or chamfered for an easy assembly.
The pin members 60 shown are made from an insulating material, namely a polymer compound, particularly comprising PEEK. The pin members 60 are configured with a thermal class assignment of at least 180 °C and with a compressive strength of at least 50 MPa. The thermal class assignment is defined according to international standard IEC 60085:2007. The pin members 60 may be produced by casting.
Not shown is a pin member that has the shape of a ball or a sphere.
With respect to Figs. 1, 2 and 4, the elastic member 50 has a thickness 51 which is below 30 mm, particularly is below 20 mm and especially is below 15 mm. The thickness 51 is at least 5 mm.
Fig. 4 shows a simplified detail of Fig. 1, where it can be seen that each of the axial end faces 30 has four recesses 36. The recesses 36 extend in depth in an axial direction of the coil 20. The coil members 31, 32 are arranged so that their recesses 36 align with one another and/or are oriented facing one another in an axial direction. The first pin ends 61 of the pin members 60 (cf. Fig. 3) project into the recesses 36 of the first coil member 31 and the second pin ends 62 of the pin members 60 (cf. Fig. 3) project into the recesses 36 of the second coil member 32.
The recesses 36 are larger in diameter 42, especially in cross-sectional area, relative to the pin members 60. The recesses 36 correspond in shape to the pin members 60 for provision of a form fit. Particularly, the diameter 42 of the recesses 36 is larger than the diameter 64 of the pin members 60, e.g. at least 1 % and up to 10 % or more, for loosely fitting into the respective recess 36.
The openings 52 of the elastic member 50 may correspond in size to the diameter 42 of the recesses 36, particularly may even be larger than the diameter 42 or size of the recesses 36.
The thickness 51 of the elastic member 50 holds the two coil members 31, 32 at a respective distance, considering that the elastic member 50 may be compressed and/or reduced in thickness 51 based on the weight of the second coil member 32.
With reference to Fig. 1, the first coil member 31 and the second coil member 32 each comprise the primary coil side 24 and the secondary coil side 28. The secondary coil side 28 is arranged radially inside the primary coil side 24.
With reference to Fig. 5A, showing a primary coil side 24 of a first coil member 31 like that of Fig. 1, recesses 36 are formed in the primary coil sides 24, respectively. The secondary coil sides, e.g. referenced by 28 in Fig. 1, preferably do not comprise such recesses 36.
With respect to Fig. 5A-B it can be seen that a pin member 60 has a diameter 64 and the first coil member 31 and typically the second coil member 32 have a thickness 34 in a radial direction. The diameter 64 of the pin member 60 is at least 20 % and up to 80 % of the thickness 34 of the coil members 31, 32. The thickness 34 of the coil members 31, 32 may be at least 50 mm and/or up to 150 mm. Particularly, the thickness 34 of the coil members 31, 32 may be 80 mm ± 10 mm, e.g. wherein the diameter 64 of the pin member 60 less than that.
With respect to Fig. 5A-B it can be seen that the coil 20 comprises four of the pin members 60 distributed along the axial end faces 30 and in a circumferential direction, each of the four pin members 60 configured for engaging with a respective recess 36 in the first and the second coil member 31, 32.
Each pin member 60 projects with its first pin end into the recess 36 of first coil member 31 and sticks out from the respective recess 36 with its second pin end 62 to be received by the recess of the second coil member (not shown in Fig. 5A). As can be seen in Fig. 5A, the pin members 60 have a flat pin end surface 66 that has a chamfered and/or rounded edge 68. The pin members 60 sit loosely in the recesses 36. An elastic member 50 (cf. Fig. 2) may be placed onto the axial end surface 30 as shown in Fig. 5A for the pin members 60 to penetrate openings 52 of the elastic members 50.
In Fig. 5B the first 31 and the second 32 coil members are stacked atop each other, wherein the pin members 60 engage with their pin ends (not shown in detail) into the coil members 31, 32 and penetrate through the elastic member 50. The coil members 31, 32 are held at a distance that substantially corresponds to a thickness 51 of the elastic member 50.
It can be seen in Fig. 5B that the coil members 31, 32 each include electrical connectors 21, e.g. accessible on a side of the coil 10 formed by the coil members 31, 32.
Producing the coil arrangement 10 of Fig. 1 may include casting the first coil member 31 and the second coil member 32, and afterwards placing the elastic member 50 between the axial end faces 30 and the pin member 60 into the recesses 36. The recesses 36 may be formed during the step of casting.
Shown and described is a coil arrangement 10 with a coil 20 that has a first 31 and a second 32 coil member. The connection between the coil members 31, 32 is achieved by using pin members 50. Four recesses 36 e.g. in the form of blind holes have been casted in a bottom facing surface of the second coil member 32, namely into one of its axial end faces 30, and four of such recesses 36 have been casted in a top facing surface of the first coil member 31, namely into one of its axial end faces 30. The pin members 50 are made of insulating material, like PEEK. To prevent a connection that is too hard or direct, reducing likeliness of material failure, a silicon rubber is set between the coil members 31, 32 in the form of an elastic member 50. The silicon rubber keeps soft connection and also provides additional horizontal fiction to prevent movement or displacement or coil members 31, 32.
Fig. 6 shows a coil 20 of a coil arrangement 10 of a transformer 1 with a first 31 and a second 32 coil section stacked atop one another. The coil sections 31, 32 are connected via blocks 90 that exhibit an H-shape, H-shaped blocks for short. The blocks 90 grab around axial end faces 30 of each coil section 31, 32 for provision of a form fit. A gap between the coil sections 31, 32 is formed where air may enter or leave the inside of the coil 20. By way of adopting the invention to the coil 20 shown in Fig. 6, which is not shown in detail, would mean that the blocks 90 are replaced by pin members engaging into the axial end faces 30 of the coil sections 31, 32 and by an elastic member.

Reference signs list

1: electrical transformer
10: coil arrangement
20: coil
21: electrical connectors
22: outer diameter
24: primary coil side
26: wall
27: partition wall
28: secondary coil side
30: axial end face
31: first coil member
32: second coil member
34: thickness
36: recess
38: inner surface
40: bottom
42: diameter
50: elastic member
51: thickness
52: opening
54: elastic member surface
56: inner diameter
58: outer diameter
60: pin member
61: first pin end
62: second pin end
64: diameter
65: length
66: pin end surface
68: edge
70: coil block
80: support base
90: block

Claims

Coil arrangement for an electrical transformer (1) and comprising
a coil (20) made from cast resin and including a first coil member (31) and a second coil member (32), wherein the first and the second coil members (31, 32) each have an axial end face (30) with a recess (36), wherein the axial end faces (30) face one another;

an elastic member (50) arranged between the axial end faces (30); and

a pin member (60) having a first pin end (61) projecting into the recess (36) of the first coil member (31) and having a second pin end (62) projecting into the recess (36) of the second coil member (32).
Coil arrangement (10) according to the preceding claim, wherein the pin member (60) has a substantially cylindrical shape particularly with substantially flat first (61) and second (62) pin ends.
Coil arrangement (10) according to any one of the preceding claims, wherein the recess (36) of the first coil member (31) and/or of the second coil member (32)
is larger in cross sectional area and/or in diameter (42) relative to the pin member (60), and/or

corresponds in shape to the pin member (60) for provision of a form fit.
Coil arrangement (10) according to any one of the preceding claims, wherein
the pin member (60) is made from an insulating material and/or a polymer compound, particularly comprising PEEK, and/or

the pin member (60) is configured with a thermal class assignment of at least 180 °C and with a compressive strength of at least 50 MPa, the thermal class assignment defined according to international standard IEC 60085:2007.
Coil arrangement (10) according to any one of the preceding claims, wherein
the pin member (60) has a diameter (64) and the first coil member (31) and/or the second coil member (32) has a thickness (34), and

the diameter (64) is at least 20% and/or up to 80% of the thickness (34), particularly is at least 30% and/or up to 70%, more particularly is at least 40% and/or up to 60%.
Coil arrangement (10) according to any one of the preceding claims, wherein the pin member (60) has a/the diameter (64) that is at least 20 mm and/or up to 80 mm, particularly is 50 mm ± 10 mm.
Coil arrangement (10) according to any one of the preceding claims, wherein the elastic member (50) is made from an electrically insulating material, particularly comprising rubber, a polymer compound and/or silicone.
Coil arrangement (10) according to any one of the preceding claims, wherein the elastic member (50) is ring-shaped.
Coil arrangement (10) according to any one of the preceding claims, wherein the elastic member (50) is in direct contact on opposite, substantially parallel sides of the elastic member (50) with the axial end faces (30), respectively.
Coil arrangement (10) according to any one of the preceding claims, wherein the elastic member (50) has an opening (52) penetrated by the pin member (60).
Coil arrangement (10) according to any one of the preceding claims, comprising two or more, particularly three or four, pin members (60) particularly distributed along the axial end faces (30) and/or in a circumferential direction, each of the two or more pin members (60) engaging with another one of the recesses (36) in the first and the second coil member (31, 32).
Coil arrangement (10) according to the preceding claim, wherein
the first coil (31) and the second coil (32) each comprise a primary coil side (24) and a secondary coil side (28),

the secondary coil side (28) is arranged radially inside the primary coil side (24), and

the recesses (36) are formed in the primary coil sides (24), respectively.
Coil arrangement (10) according to the preceding claim, wherein the coil member (31) and the second coil member (32) have an outer diameter (22), and wherein the outer diameter (22) is least 0,5 m and/or up to 1,5 m, preferably is at least 0,75 m and/or up to 1,25 m, particularly is 1,1 m ± 0,1 m.
Dry-type transformer (1) including the coil arrangement (10) according to any one of the preceding claims, wherein the second coil member (32) is configured for being arranged atop the first coil member (31).
Method to produce a coil arrangement (10) of any one of claims 1 to 13, comprising
casting the first coil member (31) and the second coil member (32), and afterwards

placing the elastic member (50) between the axial end faces (30) and the pin member (60) into the recesses (36).