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
  • H01F27/24—Magnetic cores
  • H01F27/25—Magnetic cores made from strips or ribbons
• • 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
  • H01F27/24—Magnetic cores
  • H01F27/26—Fastening parts of the core together; Fastening or mounting the core on casing or support
  • H01F27/263—Fastening parts of the core together
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F30/00—Fixed transformers not covered by group H01F19/00
  • H01F30/06—Fixed transformers not covered by group H01F19/00 characterised by the structure
  • H01F30/12—Two-phase, three-phase or polyphase transformers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
  • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
  • H01F41/0206—Manufacturing of magnetic cores by mechanical means
  • H01F41/0213—Manufacturing of magnetic circuits made from strip(s) or ribbon(s)
  • H01F41/0226—Manufacturing of magnetic circuits made from strip(s) or ribbon(s) from amorphous ribbons

Definitions

• the invention relates to a transformer-core, comprising at least three hollow- cylindrical rectangular shaped core-discs wound from a magnetic band-like material, wherein two opposed limb areas and an upper and lower yoke area are formed along a circumferential path, wherein the core-discs comprise one first and at least one second slanted area parallel to the circumferential path in the belonging limb area and wherein the at least three core-discs are connected according to a polygonal layout at their belonging first slanted areas, which are arranged adjacently face to face.
• transformers for power transmission are rated for voltage levels of for example 10kV, 60kV 110kV or above, whereas the rated power amounts for example 1 MVA, 10MVA or even 100MVA.
• Transformer cores for such transformers are typically based on stacked metal sheets of a thickness of for example 0,2mm ... 0.3mm Due to a permanent magnetic re-orientation during operation of such transformer core magnetic losses are produced, which have also a heating effect on the transformer core.
• a transformer core made from an amorphous material provides reduced core-losses in comparison to a standard transformer core.
• Amorphous material is available typically as band-like refractory material, which is extremely sensitive against any mechanical stress and has a thickness of for example 30 ⁇ or less.
• band-like refractory material typically as band-like refractory material, which is extremely sensitive against any mechanical stress and has a thickness of for example 30 ⁇ or less.
• an amorphous transformer core has to be wound from such a band-like material, whereas the width of such band might amount for example 30cm and whereas several thousand layers have to be wound.
• a wound amorphous transformer core is sensitive to any mechanical stress produced for example also by mechanical collisions. But also wearing the weight of the transformer as such has considered being mechanical stress.
• transformer cores can be constructed according to a polygonal layout, a three phase transformer preferably according to a triangular layout. Due to such a preferably complete symmetrical construction also the electrical behavior of such a transformer is symmetrical. Additional advantages are gained by a more compact and space-saving arrangement.
• a polygonal respectively triangular transformer-core is subject to a reduced stability, especially in the case that it is formed by belonging core discs.
• core discs are easier to manufacture, on the other hand the core discs as such are more fragile due to the slanted areas and a mechanically stable connection of adjacent core discs is difficult.
• a transformer core with polygonal layout has a reduced stability and in case of an amorphous transformer core which is made from a wound band-like amorphous material moreover an extremely fragile structure.
• a polygonal transformer core especially an amorphous polygonal transformer core, with increased mechanical stability.
• This problem is solved by a transformer core of the aforementioned kind. This is characterized in that at least one flat plate is foreseen in each limb area, which is connected even and stiff with a belonging adjacent slanted area.
• the basic idea of this invention consists in increasing the mechanical stability respectively stiffness of such a transformer core by connecting a flat plate on a belonging slanted area, which is characterized by a reduced mechanical stability compared to a non-slanted area.
• the flat plate and the slanted area have to be adapted concerning their basic shape.
• the cross section in the limb area of a belonging core disc is shaped in that way that no or at least nearly no gap is built inbe- tween first slanted areas of adjacent core discs.
• the adjacent core-discs are easier and more stable to connect on one side and on the other side the magnetic active cross section of a limb, which is formed by two belonging limb sections of adjacent core-discs, is increased.
• a core disc with round corners, that's layout corresponds more to an oval than to a rectangular shape has also to be seen as rectangular shaped within the frame of this invention.
• the magnetic bandlike material is comparable to typical metal sheets of stacked transformer cores and has a thickness of for example 0,2mm or 0,3mm.
• the mechanical stability of a wound core-disc is reduced compared to a stacked transformer core and is stabilized in an advantageous way by the invention.
• transformer core The principles of a transformer core according to the invention can also used for a for a reactor core for example.
• the wound magnetic band-like material is an amorphous material, which is significantly more fragile than comparable shaped metal sheets. Moreover, the thickness of layers of such amorphous material is significantly lower, for example 30 ⁇ or less. Thus the effect of mechanical stabilization of an amorphous core-disc according to the invention is once more increased.
• At least one plate is connected even and stiff at least on one of their both flat sides with the belonging adjacent slanted area by a glued bond.
• a glue based connection is rather easy to manufacture whereas at least most of the layers of the wound band-like material are fixed therewith.
• Glue in its liquid state is filling any unevenness on the slanted areas and enables a mechanical connection with a high mechanical stability.
• the flat plate connected to a aicmted area of a core-disc comprises some holes, long-holes or other cut-outs. The mechanical stability is not reduced therewith, but the weight of the transformer is reduced in an advantageous way therewith.
• the belonging first slanted areas are connected even and stiff with a belonging flat plate.
• the mechanical stabilizing effect of a plate is highest at the first slanted areas since also the connection inbe- tween adjacent core-discs are realized by using those first areas.
• Such a connection could be realized for example by a tape-like material, which is wound around adjacent core sections of adjacent core-discs so that a permanent pressure force is applied on adjacent plates.
• first slanted areas are connected even and stiff to the same plate inbetween them.
• Such connection could be realized for examples from both sides by a glue bond.
• the mechanical stability of the transformer core will be once more increased. It is not required to reopen such a core for arranging a coil on a belonging transformer limb since a conductor of such a coil can also be wound around a limb of a closed core.
• adjacent first slanted areas are connected even and stiff to belonging individual and stacked plates inbetween them.
• each belonging first area of a transformer-disc is connected to an individual flat plate, whereas the belonging plates are arranged face to face, respectively optionally with one or more additional plates inbetween them.
• each core-disc with connected flat plates thereon can be manufactured separately whereas the core-discs can be connected later on.
• the process of manufacturing the transformer core is simplified therewith in an advantageous way.
• the individual and stacked plates are connected by a glued bond, screws or welding. All kinds of connections provide a high mechanical stability, whereas a screw connection is resolvable, so that the core could become demounted.
• at least one plate is connected even and stiff to a first slanted area and is extending over the dimension of the belonging first area so that an overlaying area is formed. Since the desired magnetic characteristics of an amorphous transformer core strongly depend of not exceeding a certain temperature range, an adequate cooling of the transformer is required. By forming such overlapping areas, an additional surface for heat exchange with the environment is gained.
• At least one extending plate is bent in the overlaying area.
• the limbs formed in the belonging limb areas are surrounded by belonging second slanted areas which are connected even and stiff with belonging plates. Connecting also the second slanted areas, which are forming the outer surface of a limb composed from two limb areas, will additionally increase the mechanical stability of the transformer core. Furthermore a mechanical protection of the limb is provided therewith. Such a protection is of special interest, if the conductor of a belonging coil is wound around the limb of a ready manufactured transformer coil. In this case rotating movement is applied on the coil to be wound, which is sliding on the surface of the limb. The limb is protected against such a sliding movement therewith.
• adjacent second slanted areas are connected even and stiff with a common plate.
• a common plate is overlapping slanted areas of both adjacent core-discs so that the mechanical connection of the core-discs is improved therewith.
• the common plate is bent, so that an angle inbetween two adjacent slanted areas is compensated therewith. It has to be avoided, that an electrical conducting loop cii uund the circumference of the limb is build by adjacent plates to avoid a short- circuit current there through.
• the at least one plate consists at least predominantly of stainless steel. This material has a high mechanical stability and can easily become glued together with slanted areas of the amorphous transformer core.
• At least one of the glued bonds comprises a fibre structure.
• a glued bond is typically applied in the wet state, so that a mat of for example glass fibre can be arranged therein. Glass fibre will once more increase mechanical strength of the glued bond and of the transformer-core therewith.
• transformer-core conical shaped polygonal adapter plates fitted to the polygonal layout are foreseen within the upper and lower yoke areas, which are clamped together each to each other. Due to the conical shape of the adapter plates a kind of plug is formed therewith within each yoke area, so that a pressure force is applicable thereon. This pressure force additionally increases the mechanical stability of the transformer core.
• a thread-rod is for example a suitable means for applying such pressure force.
• a transformer comprising a transformer-core according to the invention and at least three transformer coils, which are arranged around the each limb area.
• a transformer is characterized by reduced core losses and by an increased efficiency factor therewith.
• the improved transformer-core furthermore provides an increased mechanical stability of the transformer, so that as well the transport as the arrangement on site is improved therewith in an advantageous way.
• Figure 1 shows an exemplary first core disc
• Figure 2 shows an exemplary first transformer core
• Figure 3 shows an exemplary second transformer core
• Figure 4 shows an exemplary third transformer core
• Figure 5 shows an exemplary fourth transformer-core
• Figure 6 shows an exemplary fifth transformer core with clamping fixture.
• Fig. 1 shows an exemplary first core disc 10 from a wound amorphous band-like material, whereas belonging different layers are indicated with the reference numbers 12, 14, 16.
• a real core disc comprises for example several thousand of those layers.
• the core disc 10 is hollow-cylindrical and rectangular shaped, whereas a core disc with round corners, that's layout corresponds more to an oval than to a rectangular shape, has also to be seen as rectangular shaped within the frame of this invention.
• the core disc is characterized by two opposed limb areas 20, 22 an upper 24 and a lower 26 yoke area, which are arranged along a circumferential path 18a, 18b, 18c, 18d. Slanted areas are not explicitly visible in this drawing.
• Fig. 2 shows a schematic first transformer core 30 in a simplified three-dimensional sketch.
• Three exemplary core discs 42, 44, 46 are arranged according to a polygonal respectively triangular layout 48.
• Three limb areas 36, 38, 40 are formed by the belonging sections of two adjacent core discs 42, 44, 46 each.
• the limb areas 36, 38, 40 are foreseen to arrange a belonging coil of the transformer around them.
• An upper 32 and lower 34 yoke area is formed by the upper respectively lower yokes of the adjacent core discs 42, 44, 46.
• the triangular corresponds to an equilateral triangle.
• Fig. 3 shows an exemplary second transformer core 50 from a top view and partly as cross section.
• Three core discs 52, 54, 56 are arranged according to an equilateral triangular layout.
• the cross sections of the core discs 52, 54, 56 comprise within their belonging limb areas second slanted areas 58, 62 which are forming the outside surface of the belonging composed limb.
• First slanted areas 60, 64 are foreseen, which cu e arranged face to face.
• the arrangement face to face enables for example putting a pressure force thereon, so that a mechanical connection of the core discs 52, 54, 56 is simplified therewith.
• An exemplary first plate 66 is arranged inbetween two adjacent first slanted areas of the transformer discs 52, 54, 56.
• This plate 66 is for example connected by a glued bond with the belonging first slanted areas.
• An exemplary second plate 68 is foreseen inbetween two adjacent other first slanted areas.
• This plate 68 is characterized by bent section 72, so that an overlaying area 70 is formed, which is on one side stabilizing the mounted transformer core and which on the other side has a cooling effect on the transformer core.
• a real transformer core 50 has to be arranged preferably symmetrically concerning the arrangement of the plates 66, 68.
• Fig. 4 shows an exemplary third transformer core 80 from a top view and partly as cross section.
• Two core discs 82, 84 are arranged adjacently face to face at their belonging first slanted areas 90, 94, whereas also second slanted areas 86 are foreseen at the outside surface of the composed limb.
• first slanted areas 90, 94 U-shaped plates 88, 92 are connected with a glued bond.
• the U-shape indicated for example by an bent section 96, improves especially mechanical stability of the transformer core 80.
• Fig. 5 shows an exemplary fourth transformer-core 100 from a top view and partly as cross section.
• Two core discs 102, 104 are arranged adjacently face to face at their belonging first slanted areas.
• a composed limb is formed by the belonging sections of the core discs 102, 04 and is surrounded by a virtual path, which is indicated with the reference number 108.
• Common bent plates 106 are foreseen along the path 108 and connected with belonging second slanted areas of the composed limb, for example with a belonging glued bond.
• the mechanical connection of the core discs 102, 104 is increased therewith.
• the composed limb is mechanically protected by those plates 106, for example if a coil is wound around such a limb of a mounted transformer core during manufacturing.
• Fig. 6 shows an exemplary fifth transformer core 110 with a clamping fixture 118 + 120 + 122 + 124 + 126 from a side view.
• a core disc 112 is shown from its side, whereas two other core discs, which all three are mounted together to a transformer cult?, are not shown.
• An upper 1 14 and lower 1 16 yoke area is formed by the three upper and lower yokes of the core discs.
• a conical shaped upper 1 18 and lower 120 adapter plate is inserted in the inner yoke areas 1 14 respectively 1 16, whereas adapter plates 1 18, 120 and inner yoke areas 1 14, 1 16 are adapted concerning their shapes.
• a pressure force can be applied inbetween both adapter plates 1 18, 120, which clamps them together.
• the pressure force is applied by a threaded rod 122 with upper 124 and lower screw nut. Applying such a pressure force increases the mechanical stability of the transformer core 1 10 in an advantageous way.
• first layer of amorphous band-like material second layer of amorphous band-like material third layer of amorphous band-like materiala first section of circumferential path
• first plate connected with first slanted area of first core disc first slanted area of first core disc

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• 2012
  • 2012-01-18 EP EP12000264.7A patent/EP2618347B1/en active Active
  • 2012-01-18 ES ES12000264T patent/ES2841062T3/es active Active
  • 2012-12-07 CN CN201280067489.3A patent/CN104040651B/zh active Active
  • 2012-12-07 WO PCT/EP2012/005058 patent/WO2013107480A1/en active Application Filing

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