EP4006926A1 - Cadre pressé pour une coulasse d'un noyau de transformateur - Google Patents

Cadre pressé pour une coulasse d'un noyau de transformateur Download PDF

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Publication number
EP4006926A1
EP4006926A1 EP21207939.6A EP21207939A EP4006926A1 EP 4006926 A1 EP4006926 A1 EP 4006926A1 EP 21207939 A EP21207939 A EP 21207939A EP 4006926 A1 EP4006926 A1 EP 4006926A1
Authority
EP
European Patent Office
Prior art keywords
frame
yoke
press frame
press
frame part
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.)
Withdrawn
Application number
EP21207939.6A
Other languages
German (de)
English (en)
Inventor
Sarvesh Ambekar
Deepak Mahajan
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.)
Siemens Energy Global GmbH and Co KG
Original Assignee
Siemens Energy Global GmbH and Co KG
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 Siemens Energy Global GmbH and Co KG filed Critical Siemens Energy Global GmbH and Co KG
Publication of EP4006926A1 publication Critical patent/EP4006926A1/fr
Withdrawn legal-status Critical Current

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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
    • H01F27/245—Magnetic cores made from sheets, e.g. grain-oriented
    • 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
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/341—Preventing or reducing no-load losses or reactive currents
    • 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
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F2027/348—Preventing eddy currents

Definitions

  • the invention relates to a press frame for a yoke of a transformer core and a transformer.
  • a transformer in particular a power transformer for high electrical power, usually has a transformer core which consists of stacks of laminations that are electrically insulated from one another. Constructing the transformer core from electrical laminations advantageously reduces electrical eddy currents within the transformer core during operation of the transformer and thus increases the efficiency of the transformer.
  • the transformer core has a plurality of core limbs, around which windings of the transformer run. To form a closed magnetic circuit in the transformer core, the ends of the core legs are connected to one another via yokes. The yokes are usually clamped in a press frame in order to hold the laminations of the yokes together.
  • a press frame for a yoke generally has two frame parts which are arranged on opposite outer sides of the yoke and between which tension elements are stretched.
  • the frame parts and the tension elements are usually made of metal, in which the electromagnetic stray fields of the transformer can induce electrical eddy currents. These eddy currents can lead to power losses in the transformer and to hot spots in the press frame, particularly in its tension elements.
  • the invention is based on the object of specifying an improved pressing frame for a yoke of a transformer core.
  • the object is achieved according to the invention by a press frame having the features of claim 1 and a transformer having the features of claim 11 .
  • a press frame according to the invention for a yoke of a transformer core comprises two frame parts, which can be arranged on opposite outer sides of the yoke, and several tension elements, which each extend from one frame part to the other frame part and are made of austenitic, stainless and non-magnetizable steel.
  • Non-magnetizable steel is understood to mean steel that has negligible or very low magnetic susceptibility and thus a permeability number close to one.
  • Tension elements made of austenitic, stainless and non-magnetizable steel have a combination of corrosion resistance, ductility, toughness and magnetic properties that enable stable clamping of a yoke of a transformer core with low eddy currents induced in the tension elements by electromagnetic fields.
  • Tension elements of this type are therefore advantageously suitable for bracing a yoke of a transformer in areas that are exposed to strong electromagnetic stray fields from the transformer during operation of the transformer.
  • the use of tension elements designed according to the invention in such areas reduces power losses of the transformer caused by stray fields and the occurrence of hot spots in the tension elements.
  • the tension elements are made of steel X12CrMnNiN18-9-5 with the material number 1.4373, steel X5CrNi18-10 with the material number 1.4301, steel X2CrNi18-9 with the material number 1.4307, steel X6CrNiTi18-10 with the material number 1.4541 and/or made of steel X2CrNiMo17-12-2 with the material number 1.4404 according to the European standard EN 10027-2.
  • These steels are particularly suitable as materials for the above-mentioned tension elements of a press frame, because they retain negligible or very low magnetizability even after extensive deep-drawing, which is used to improve the mechanical properties of these steels, in particular to increase their yield strength and tensile strength.
  • the tension elements have end regions which are designed in the manner of cylinders. Furthermore, each end area is guided through a frame part opening in one of the frame parts and has an external thread which is screwed to a threaded nut, by which the end area is secured against sliding out of the frame part opening.
  • the tension elements can advantageously be clamped between the frame parts in order to clamp a yoke arranged between the frame parts.
  • a shielding cap is arranged around the ends of the tension elements protruding from the frame part openings of at least one frame part, and/or the ends of the tension elements guided through the frame part openings of at least one frame part are guided through the frame part openings in an electrically insulated manner.
  • This development of the invention is particularly advantageous when one of the frame parts is exposed to particularly strong electromagnetic stray fields. This can be the case in particular when the high-voltage winding connections of high-voltage windings of the transformer are arranged on one side of the transformer, the so-called high-voltage side, as is often the case. Stray electromagnetic fields can induce eddy currents in the press frame.
  • the electrical insulation of the tension elements from at least one frame part advantageously prevents the flow of eddy currents between the frame parts of the press frame.
  • the tension elements each have a between the end areas running, band-like central area.
  • the end areas of a tension element are welded to the central area of the tension element.
  • the central area of a tension element has, for example, a cross section in the form of a rectangle with rounded corners. As a result, advantageously large electric field strengths at the edges of the central area can be avoided.
  • At least one section of the central region of a tension element can be encased with an electrically insulating insulation layer.
  • the dielectric resistance of the tension element can advantageously be increased in sections of the central area that are subject to particularly high electromagnetic loads.
  • the central region of a tension element can also have a number of sections which are angled towards one another.
  • the central area can advantageously be adapted to the configuration of a surface of a yoke on which the tension element runs if this surface is not flat.
  • a transformer according to the invention comprises a transformer core which has two yokes and core legs arranged between the yokes, windings which each run around at least one core leg, and at least one press frame according to the invention which is arranged on a yoke.
  • the frame parts of the press frame are arranged on opposite outer sides of the yoke.
  • tension elements of the press frame made of austenitic, stainless and non-magnetizable steel each run on a surface of the yoke facing the other yoke and are clamped between the frame parts of the press frame.
  • the design of a transformer according to the invention takes into account that in the areas of mutually facing surfaces of the yokes of a transformer during its operation, in particular strong stray electromagnetic fields can occur since these areas are close to the windings of the transformer. Tension elements that run in these areas are therefore exposed to particularly strong stray electromagnetic fields, so that these tension elements advantageously have the above-mentioned configuration according to the invention.
  • the Figures 1 to 3 show an embodiment of a transformer 1 according to the invention and components of the transformer 1.
  • the transformer 1 comprises a transformer core 3, which has two yokes 5 and five core legs 7, 9, windings 11, 13 and for each yoke 5 a press frame 15 according to the invention.
  • a coordinate system with Cartesian coordinates X, Y, Z is drawn in each case.
  • FIG 1 shows a schematic sectional representation of the transformer 1 with a sectional plane that runs through the upper yoke 5. Under the upper yoke 5 that becomes in figure 2 Yoke 5 shown above understood.
  • FIG 2 shows a schematic sectional view of the transformer core 3 and the windings 11, 13 with a sectional plane that runs through both yokes 5 and all core legs 7, 9.
  • Figure 3 shows a perspective view of a portion of the press frame 15 for the top yoke 5.
  • the yokes 5 and core legs 7, 9 are each formed as a laminated core made of electrical laminations.
  • the core limbs 7, 9 run at a distance from each other between the two yokes 5.
  • a high-voltage winding 11 and a low-voltage winding 13 run around each of the three inner core limbs 9. No windings 11, 13 run around the two outer core limbs 7.
  • the high-voltage windings 11 have high-voltage winding connections (not shown) which are arranged on a high-voltage side 17 of the transformer 1 .
  • the low-voltage windings 13 have (not shown) low-voltage winding terminals on one of the high-voltage side 17 opposite low-voltage side 19 of the transformer 1 are arranged.
  • the pressing frame 15 of each yoke 5 has a high-side frame part 21 and a low-side frame part 23 .
  • the high-voltage side frame part 21 is arranged on a high-voltage side outer side 25 of the yoke 5 which faces the high-voltage side 17 .
  • the frame part 23 on the low-voltage side is arranged on an outer side 27 of the yoke 5 on the low-voltage side, which faces the low-voltage side 19 .
  • a cross member 29 connects one end of the high-voltage side frame member 21 and one end of the low-voltage side frame member 23.
  • the press frame 15 of each yoke 5 has a plurality of tension elements 31 .
  • Each tension element 31 is stretched between the high-voltage-side frame part 21 and the low-voltage-side frame part 23 of the press frame 15 and runs on a surface 33 facing the other yoke 5 of that yoke 5 on which the press frame 15 is arranged.
  • a group 35 of several tension elements 31 is arranged on each yoke 5 between two adjacent core legs 7 , 9 , which extend parallel to one another between the frame parts 21 , 23 of the pressing frame 15 arranged on the yoke 5 .
  • figure 3 shows such a group 35 of tension elements 31.
  • the pressing frame 15 of a yoke 5 can have further clamping elements 36 which run between the frame parts 21, 23 on a surface 37 facing away from the other yoke 5 in each case. Furthermore, the press frames 15 of the two yokes 5 are connected to one another by connecting elements (not shown), which run between the high-voltage-side frame parts 21 or the low-voltage-side frame parts 23 of the two press frames 15 and brace the transformer core 3 and the windings 11.
  • Figures 4 to 6 show different representations of an embodiment of a tension element 31.
  • Figure 4 FIG 4
  • Figure 5 FIG 5
  • Figure 6 FIG 6
  • Figure 4 FIG 4
  • Figure 5 FIG 5
  • Figure 6 FIG 6
  • the pulling element 31 has end regions 39 designed in the manner of a cylinder and a central region 41 designed in the manner of a strip and running between the end regions 39 .
  • Each end area 39 has an external thread 43 for tensioning the tension element 31 between the frame parts 21 of a press frame 15 (see the figures 7 and 8th and their description).
  • the central area 41 has a cross section in the form of a rectangle with rounded corners (see FIG figure 6 ).
  • Each end area 39 also has a slot 44 into which one end of the middle area 41 is inserted and in the area of which the middle area 41 is welded to the end area 39 .
  • the central area 41 has several (three in this exemplary embodiment) sections 41.1, 41.2, 41.3 which are angled towards one another.
  • a central section 41.2 has an angle ⁇ to both adjacent sections 41.1, 41.3, which corresponds to a configuration of the surface 33 of a yoke 5, on which the tension element 31 runs (in this case, the surface 33 is not flat , but has a flat area, which is adjoined on both sides by an angled or curved edge area).
  • the tension element 31 is made of austenitic, stainless and non-magnetizable steel, for example steel X12CrMnNiN18-9-5 with the material number 1.4373, steel X5CrNi18-10 with the material number 1.4301, steel X2CrNi18-9 with the material number 1.4307, steel X6CrNiTi18 -10 with the material number 1.4541 and/or from Steel X2CrNiMo17-12-2 with the material number 1.4404 according to the European standard EN 10027-2.
  • the outer sections 41.1 and 41.3 of the central area 41 are also covered with a suitable electrically insulating insulation layer 45 to improve their dielectric strength.
  • the middle section 41.2 can also be covered with a (possibly different) insulating layer if this is necessary.
  • FIG 7 shows a sectional view of the press frame 15 of the upper yoke 5 in the area of an end of a tension element 31 arranged on the high-voltage side frame part 21 of the press frame 15.
  • the frame part 21 has a high-voltage side frame part opening 47 through which an end area 39 of the tension element 31 can be inserted in an electrically insulating Insulator sleeve 49 is performed.
  • the insulator sleeve 49 is made, for example, from pressboard or from a glass fiber reinforced plastic.
  • the external thread 43 of the end area 39 is screwed to a threaded nut 51 by which the end area 39 is secured against sliding out of the frame part opening 47 .
  • a shielding cap 53 with a convex outer surface facing away from the frame part 21 is arranged around the end of the tension element 31 and the threaded nut 51 .
  • the shielding cap 53 is arranged in an insulator shell 55 .
  • the insulator shell 55 is formed from pressboard, for example.
  • the insulator shell 55 is embedded in an extension of the frame part opening 47 formed in the frame part 21 and a support part 57 arranged on the frame part 21 .
  • a bottom 59 of the insulator shell 55 has an opening to the frame part opening 47, through which the end region 39 is guided.
  • a metal washer 61, a tolerance compensation washer 63 and an insulator washer 65 are arranged between the bottom 59 of the insulator shell 55 and the shielding cap 53. each having an opening through which the end portion 39 is guided. One end of the insulator sleeve 49 is also guided through the opening in the insulator disc 65 .
  • the insulator disc 65 rests against the bottom 59 of the insulator shell 55 and is made of glass fiber reinforced plastic, for example.
  • the tolerance compensation disc 63 rests against the insulator disc 65 and is made of pressboard, for example.
  • the washer 61 rests against the tolerance compensation disk 63 and an underside of the shielding cap 53 facing the frame part opening 47 .
  • FIG 8 shows a perspective view of the press frame 15 of the upper yoke 5 in the area of an end of a tension element 31 arranged on the low-voltage side frame part 23 of the press frame 15.
  • the frame part 23 has a low-voltage side frame part opening 67 through which an end region 39 of the tension element 31 is guided.
  • the frame part opening 67 widens towards a side of the frame part 23 facing away from the yoke 5.
  • a metal washer 61 is arranged between a bottom of the widening 69 and the threaded nut 51 and has an opening through which the end region 39 is guided.
  • the different fastenings of the tension elements 31 on the high-voltage-side frame part 21 and the low-voltage-side frame part 23 of a press frame 15 serve to prevent the flow of eddy currents between the frame parts 21, 23 by the electrical insulation of the tension elements 31 with respect to the high-voltage-side frame part 21.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Coils Of Transformers For General Uses (AREA)
EP21207939.6A 2020-11-26 2021-11-12 Cadre pressé pour une coulasse d'un noyau de transformateur Withdrawn EP4006926A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102020214854.6A DE102020214854A1 (de) 2020-11-26 2020-11-26 Pressrahmen für ein Joch eines Transformatorkerns

Publications (1)

Publication Number Publication Date
EP4006926A1 true EP4006926A1 (fr) 2022-06-01

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ID=78617274

Family Applications (1)

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EP21207939.6A Withdrawn EP4006926A1 (fr) 2020-11-26 2021-11-12 Cadre pressé pour une coulasse d'un noyau de transformateur

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EP (1) EP4006926A1 (fr)
DE (1) DE102020214854A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN202384143U (zh) * 2011-12-29 2012-08-15 广东广特电气有限公司 一种变压器铁芯铁轭的不对称夹紧结构
WO2015021819A1 (fr) * 2013-08-12 2015-02-19 山东电力设备有限公司 Structure de serrage de culasse de fer de réactance à cœur de fer
CN104934197A (zh) * 2015-06-26 2015-09-23 镇江天力变压器有限公司 一种环氧浇注干式变压器铁芯夹紧降噪结构
CN110911123A (zh) * 2019-12-09 2020-03-24 吴江变压器有限公司 一种铁心电抗器的旁轭夹紧结构

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59217310A (ja) 1983-05-26 1984-12-07 Toshiba Corp 静止誘導電器の鉄心締付構造
WO2000002211A1 (fr) 1998-07-02 2000-01-13 Siemens Aktiengesellschaft Composant a induction presentant un noyau
EP3667687A1 (fr) 2018-12-12 2020-06-17 Siemens Aktiengesellschaft Système de serrage pour transformateur électrique

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN202384143U (zh) * 2011-12-29 2012-08-15 广东广特电气有限公司 一种变压器铁芯铁轭的不对称夹紧结构
WO2015021819A1 (fr) * 2013-08-12 2015-02-19 山东电力设备有限公司 Structure de serrage de culasse de fer de réactance à cœur de fer
CN104934197A (zh) * 2015-06-26 2015-09-23 镇江天力变压器有限公司 一种环氧浇注干式变压器铁芯夹紧降噪结构
CN110911123A (zh) * 2019-12-09 2020-03-24 吴江变压器有限公司 一种铁心电抗器的旁轭夹紧结构

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DR.RER.NAT. FOFANOV DENIS ET AL: "Magnetische Eigenschaften nichtrostender Stähle Merkblatt 827 Die Informations- stelle Edelstahl Rostfrei", MERKBLATT 827, 31 December 2013 (2013-12-31), pages 1 - 21, XP055912202, Retrieved from the Internet <URL:https://www.edelstahl-rostfrei.de/fileadmin/user_upload/ISER/downloads/MB_827.pdf> [retrieved on 20220412] *

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