EP3159904A1 - Trockener giesstransformator mit flexibler anschlussklemme - Google Patents

Trockener giesstransformator mit flexibler anschlussklemme Download PDF

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Publication number
EP3159904A1
EP3159904A1 EP15197556.2A EP15197556A EP3159904A1 EP 3159904 A1 EP3159904 A1 EP 3159904A1 EP 15197556 A EP15197556 A EP 15197556A EP 3159904 A1 EP3159904 A1 EP 3159904A1
Authority
EP
European Patent Office
Prior art keywords
coil
cast
insulated cable
cable termination
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.)
Withdrawn
Application number
EP15197556.2A
Other languages
English (en)
French (fr)
Inventor
Carlos Roy
Rafael Murillo
Barrieras Antonio Nogues
M Lorena Cebrian Lles
Luis Sanchez
Rahul Shah
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.)
ABB Schweiz AG
Original Assignee
ABB Schweiz AG
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 ABB Schweiz AG filed Critical ABB Schweiz AG
Priority to DK16781720.4T priority Critical patent/DK3365903T3/da
Priority to ES16781720T priority patent/ES2784365T3/es
Priority to PL16781720T priority patent/PL3365903T3/pl
Priority to KR1020187014236A priority patent/KR101929184B1/ko
Priority to PCT/EP2016/074037 priority patent/WO2017067798A1/en
Priority to EP16781720.4A priority patent/EP3365903B1/de
Priority to CN201680074783.5A priority patent/CN108369855B/zh
Publication of EP3159904A1 publication Critical patent/EP3159904A1/de
Priority to US15/958,302 priority patent/US10755851B2/en
Withdrawn legal-status Critical Current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
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/327—Encapsulating or impregnating
    • 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
    • H01F27/29—Terminals; Tapping arrangements for signal inductances
    • 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
    • H01F41/04—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 for manufacturing coils
    • H01F41/12—Insulating of windings
    • H01F41/127—Encapsulating or impregnating
    • 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
    • H01F27/327—Encapsulating or impregnating
    • H01F2027/328—Dry-type transformer with encapsulated foil winding, e.g. windings coaxially arranged on core legs with spacers for cooling and with three phases
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F29/00—Variable transformers or inductances not covered by group H01F21/00
    • H01F29/02—Variable transformers or inductances not covered by group H01F21/00 with tappings on coil or winding; with provision for rearrangement or interconnection of windings

Definitions

  • This disclosure relates to the field of electrical transformers, particularly to medium and high voltage transformers of the dry-cast type having electrical connection terminals with improved connection terminals.
  • the terminals for the lines connection often consist of bared bolts, which can be placed at the top and bottom edges of the phase.
  • the terminals have no special insulation, or they may have grooves in order to increase the creepage distance against earth potential or other live points in the same winding.
  • smooth bushings may be applied which increase the creepage distance.
  • bushings that are equipped with additional sheds, e.g., for high levels ofpollution or even for outdoor installation.
  • tap-changer terminals consisting of groups of bared bolts placed in the middle of the winding, there is typically no special insulation applied around them.
  • protrusions, grooves, or even bushings may be applied.
  • the known techniques may suffer from various isolation issues. Further, if such issues are addressed by employing bushings or the like, enhanced production cost will and enhanced risk of damage can result, e.g. during transportation of the transformer.
  • a dry type cast-coil transformer having a voltage rating of 1 kV and above, comprising at least one coil with a number of conductor turns; a cast comprising a polymeric resin, encompassing the coil and having a cast surface; a ferromagnetic core on which the coil with the encompassing cast is mounted; and an insulated cable termination connected to the coil, wherein the connection point between the insulated cable termination and the coil is within the cast, and wherein a flexible portion of the insulated cable termination further extends from the cast surface outwards.
  • a method of producing a dry cast transformer for voltage ratings above 1 kV comprising providing a coil; providing at least one cable being at least partially flexible, and connecting it to the coil to form an insulated cable termination; providing a cast of polymeric resin in a casting process employing a mold to encompass the winding in the cast, wherein the casting process is adapted such that the connection point between the first insulated cable termination and the coil is within the cast, and wherein a flexible portion of the first insulated cable termination further extends from the cast surface outwards.
  • a dry-type cast-coil transformer 10 according to embodiments is shown.
  • the transformer 10 comprises at least one coil 14.
  • the coil has a plurality of conductor turns 16.
  • the conductor turns are typically made of metal, e.g. copper or aluminum, also other conducting materials might be employed.
  • a cast 20 comprising a polymeric resin, typically epoxy resin, is encompassing the coil 14.
  • the cast 20 has a cast surface 22. This coil which is encompassed in the cast is mounted on a ferromagnetic core 24, wherein the latter is only shown schematically in the accompanying drawings.
  • Such dry-type cast-coil transformers 10 are construed for voltages on the HV side from about 1 kV to about 123 kV or 145kV, more typically from about 10 kV to about 72 kV.
  • the dry-type transformers according to the embodiments have power ratings of 10 kVA or greater, more typically 1 MVA or greater, up to 63 MVA.
  • At least one insulated cable termination 30 is connected to the coil 14.
  • the connection point 32 between the insulated cable termination 30 and the coil 14 is within the resin body of the cast 20.
  • a flexible portion 34 of the insulated cable termination 30 further extends from the cast surface 22 outwards - wherein typically, the insulated cable termination 30 is flexible over its entire length from the connection point 32 to the end of the flexible portion 34.
  • a first part of the insulated cable termination 30 extends from the connection point 32 through a portion of the cast 20 to the cast surface 22, and a second, flexible part of the insulated cable termination 30 further extends from the cast surface 22 outwards.
  • the second part, which forms the flexible portion 34 of the insulated cable termination 30, thereby forms a flexible terminal connection with the coil 14.
  • the flexible portion 34 protrudes out of the cast surface 22.
  • the cable 31 used for producing the insulated cable termination 30 has typically an insulation with a plastic layer or sheath over its entire length.
  • the flexible portion 34 protrudes out of the cast surface 22 having an insulation, such that there is a gapless insulation extending from the cast surface over the flexible portion 34.
  • This insulation is proof with respect to protection against, e.g., elevated levels of ambient moisture or increased air pollution.
  • the insulation and the creepage distance between the terminals, and between terminals and the cast surface are increased. This allows to avoid the use ofunpractical large clearances, and generally increases the lightning impulse withstand voltage and also the power frequency withstand voltage.
  • the flexible portion 34 reduces risk of damage of terminals, as it just bends when accidentally stressed, e.g., during transport.
  • connection point 32 between the insulated cable termination 30 and the coil 14 is within the resin body of the cast 20. As shown in Fig. 1 , the connection between the insulated cable termination 30 and the coil 14 may typically be carried out in the form of a screw-type terminal. The connection at connection point 32 may also be carried out differently, e.g., welded, crimped, or soldered.
  • the flexible portion 34 At the end of the flexible portion 34, there is in practical use typically a blank metallic portion or a termination (not shown in Fig. 1 , see Fig. 3 ) for a connection to other components.
  • the flexible portion 34 is not particularly limited in its length. It may have a length from a few centimeters, e.g. 10 cm, allowing a connection to other parts, up to several meters, e.g., 1m, 2m, 5m, or 10m.
  • This kind of insulated cable termination which provides a flexible terminal connection, may be used, e.g., for a direct connection of the transformer 10 with another electrical component, such as a support insulator, a circuit breaker, an on-load tap-changer, etc., without breaking the insulation.
  • another electrical component such as a support insulator, a circuit breaker, an on-load tap-changer, etc.
  • the most stressed terminals are the beginning and end of each phase, and so the greatest benefit is expected when these are provided such as described above; although also any intermediate terminals may so be provided, e.g. for a series connection or for the plurality of connections to a tap-changer.
  • Fig. 2 for further enhancing protection against creepage, the similar transformer 10 as in Fig. 1 is shown, which has three additional cylindrical insulation screens 40, 41, 42. These further increase insulation properties and increase creepage distance(s) between the flexible portion 34 and other insulated cable terminations (not shown) positioned adjacent to the insulated cable termination 30 shown in Fig. 2 .
  • the cylindrical insulation screens 40, 41, 42 are typically placed prior to the casting process of the coil 14 and form an integral part with the cast after the casting is finished. The creepage distance along the external epoxy surface is thereby further increased. The shape, material, number, thickness and lengths of the screens depends on the required insulation.
  • up to three glass-fibre cylindrical insulation screens 40, 41, 42 with a wall thickness of about 3 to 6 mm each, and a length between 100 to 300 mm (in a direction perpendicular to the cast surface 22) may be suitable.
  • a transformer according to embodiments is shown, further comprising a plurality of sheds 36 provided around the flexible portion 34 of the insulated cable termination 30. That is, the sheds 36 are provided for at least a part of the length of the flexible portion 34 outwards from the cast surface 22.
  • the insulated cable termination 30 is used to provide a flexible, but stable terminal at the transformer itself. The length of the termination and the number and type of its sheds depends on the required insulation.
  • the insulated cable and its termination 39 are typically arranged prior to the casting process forming the cast 20 around the coil 14.
  • the conductor turns 16 (shown only in reduced number in the drawings) of the coil 14 typically comprise a solid metallic material, in particular a single wound metal wire of, e.g., Cu or Aluminium, with an insulation.
  • the cable of the insulated terminal connection 30, at least the flexible portion 34 thereof, typically comprises a plurality of metal wires 35 in order to ensure the desired flexibility. In other words, it typically comprises litz wire or braided/stranded wire.
  • the conductor turns 16 of the coil 14 typically have a cross section of at least 10 mm 2
  • the insulated cable termination 30 also has a cross section of at least 10 mm 2 .
  • a transformer according to embodiments is shown, wherein the arrangement of Fig. 3 , comprising a plurality of sheds 36, is combined with the cylindrical insulation screens 40,41,42 as shown in Fig. 2 .
  • the creepage distance is further increased by combining the effects of both the sheds 36 and the cylindrical insulation screens 40, 41, 42.
  • the transformer 10 described with respect to the drawings is just exemplary. Typically, it may have at least one further insulated cable termination 30 as described, such that at least the high voltage coil (or high voltage winding) is fully equipped with is. Also, typically all terminals of a transformer, including high voltage side and low voltage side, may be equipped with such insulated cable terminations.
  • the transformer may be a three-phase-transformer.
  • it may comprise at least three coils 14, or greater numbers like six or nine coils 14.
  • one, two or three coils 14 each may be encompassed in an individual cast 20.
  • the transformer may also comprise a tap changing mechanism provided outwards from the coils 14, wherein at least a part of the plurality of insulated cable terminations 30 is connected to the tap changing mechanism.
  • a method for producing a transformer 10 as described, a method according to embodiments is provided. It comprises producing and providing a coil 14 having a plurality of conductor turns 16. At least one cable 31 is provided being at least partially flexible, and is connected to the coil 14, such that the cable 31 forms an insulated cable termination 30 for the coil 14. Then, a cast 20 of polymeric resin is produced in a casting process employing a mold 21 to encompass the coil in the cast 20.
  • Fig. 5 the mold 21 is shown in which the coil 14 is provided for the casting process according to a method of embodiments.
  • the cable 31, which will form the insulated cable termination 30 after the casting, is provided to be connected to the coil 14 at connection point 32, typically with a screw-type terminal.
  • the connection at connection point 32 may also be carried out differently, e.g., welded, crimped, or soldered.
  • Cable 31 is provided to extend through the recess 28 in the mold 21, at which position it will extend from the cast 20 as the flexible portion 34, after the casting process is finished. After the casting process is finished, cable 31 forms the insulated cable termination 30.
  • the casting process is adapted such that the connection point 32 between the insulated cable termination 30 and the coil 14 is within the cast 20. Further, it is provided that a flexible portion of the insulated cable termination 30 extends from the cast surface 22 outwards.
  • the mold 21 typically has at least one recess 28 through which the cable 31 is placed prior to the casting process.
  • the conductor turns 16 of the coil 14 typically comprise a solid metallic material with an insulation between the conductor turns 16, and at least the flexible portion of the insulated cable termination 30 comprises a plurality of metal wires, thus, it typically comprises litz wire or braided/stranded wire
  • a plurality of sheds 36 is provided around the flexible portion 34 of the insulated cable terminal 30 for at least a part of its length which extends outwards from the cast surface 22. These may typically be provided prior to the casting process or afterwards, depending on, for example, if the flexible portion 34 has a termination 39 (see Fig. 4 ) which might hinder their mounting after the casting process is finished.
  • the cable 31 may be provided prior to the casting to have a spiral form on at least a part of its length between the connection point 32 to the coil 14 and the position at which the cable passes the cast surface 22 after the casting process is finished.
  • the insulation and the creepage distance are increased, avoiding the use of unpractical big clearances. This is particularly useful for terminals with higher electrical stress, e.g., the line terminals, and also where there is a high concentration of terminals in a reduced area e.g. at the tap-changer.
  • the shape of the terminals is improved from the point of view of the electrical stress. While in the standard solution, rectangular-shaped bars and cable lugs are used, with the insulated cable only cylindrical elements are used. Hence, the electrical stress is smoother than in the standard case.
  • the internal arrangement and the physical links with the coil are also improved, as the required space is reduced.
  • the reason for this is, that the cable of the insulated terminal connection has a circular cross-section, and the fact that it is already insulated. This is useful in particular for the tap-changer.
  • Embodiments can be applied in transformers with a high insulation level or in transformers with reduced dimensions between terminals, which makes insulation difficult in general.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Coils Of Transformers For General Uses (AREA)
EP15197556.2A 2015-10-20 2015-12-02 Trockener giesstransformator mit flexibler anschlussklemme Withdrawn EP3159904A1 (de)

Priority Applications (8)

Application Number Priority Date Filing Date Title
DK16781720.4T DK3365903T3 (da) 2015-10-20 2016-10-07 Type tørstøbt transformer med fleksibel forbindelsesterminal
ES16781720T ES2784365T3 (es) 2015-10-20 2016-10-07 Transformador encapsulado de tipo seco con terminal de conexión flexible
PL16781720T PL3365903T3 (pl) 2015-10-20 2016-10-07 Transformator typu suchego żywicznego z elastycznym zaciskiem przyłączeniowym
KR1020187014236A KR101929184B1 (ko) 2015-10-20 2016-10-07 가요성의 연결 단자를 갖는 건식 타입 캐스트 변압기
PCT/EP2016/074037 WO2017067798A1 (en) 2015-10-20 2016-10-07 Dry type cast transformer with flexible connection terminal
EP16781720.4A EP3365903B1 (de) 2015-10-20 2016-10-07 Trockener giesstransformator mit flexibler anschlussklemme
CN201680074783.5A CN108369855B (zh) 2015-10-20 2016-10-07 带有柔性连接端子的干式铸造变压器
US15/958,302 US10755851B2 (en) 2015-10-20 2018-04-20 Dry type cast transformer with flexible connection terminal

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IN5649LL2015 2015-10-20

Publications (1)

Publication Number Publication Date
EP3159904A1 true EP3159904A1 (de) 2017-04-26

Family

ID=54771015

Family Applications (1)

Application Number Title Priority Date Filing Date
EP15197556.2A Withdrawn EP3159904A1 (de) 2015-10-20 2015-12-02 Trockener giesstransformator mit flexibler anschlussklemme

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EP (1) EP3159904A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3836172A1 (de) * 2019-12-12 2021-06-16 ABB Power Grids Switzerland AG Mittelfrequenztransformator mit parallelen wicklungen

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3569884A (en) * 1969-04-14 1971-03-09 Westinghouse Electric Corp Transformer coil wound from sheet conductor and cast in a resin housing
GB1602970A (en) * 1978-05-31 1981-11-18 English Electric Co Ltd Three phase transformers
AU521297B2 (en) * 1978-11-01 1982-03-25 English Electric Co. Ltd., The Encapsulated high voltage windings
US4521954A (en) * 1983-07-11 1985-06-11 General Electric Company Method for making a dry type transformer
EP2075806A1 (de) * 2007-12-27 2009-07-01 Elettromeccanica di Marnate S.p.A. Trockenharzisolierter Transformator mit abgeschirmten nebeneinander liegenden Primärwindungen
US20090284338A1 (en) * 2008-05-15 2009-11-19 Eisuke Maruyama Multi-Stage Coil for Transformer, and Coil Winding Method and Apparatus for Manufacturing the Same
EP2797088A1 (de) * 2013-04-23 2014-10-29 ABB Technology AG Spule für einen Trockentransformator und Trockentransformator

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3569884A (en) * 1969-04-14 1971-03-09 Westinghouse Electric Corp Transformer coil wound from sheet conductor and cast in a resin housing
GB1602970A (en) * 1978-05-31 1981-11-18 English Electric Co Ltd Three phase transformers
AU521297B2 (en) * 1978-11-01 1982-03-25 English Electric Co. Ltd., The Encapsulated high voltage windings
US4521954A (en) * 1983-07-11 1985-06-11 General Electric Company Method for making a dry type transformer
EP2075806A1 (de) * 2007-12-27 2009-07-01 Elettromeccanica di Marnate S.p.A. Trockenharzisolierter Transformator mit abgeschirmten nebeneinander liegenden Primärwindungen
US20090284338A1 (en) * 2008-05-15 2009-11-19 Eisuke Maruyama Multi-Stage Coil for Transformer, and Coil Winding Method and Apparatus for Manufacturing the Same
EP2797088A1 (de) * 2013-04-23 2014-10-29 ABB Technology AG Spule für einen Trockentransformator und Trockentransformator

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3836172A1 (de) * 2019-12-12 2021-06-16 ABB Power Grids Switzerland AG Mittelfrequenztransformator mit parallelen wicklungen
WO2021115966A1 (en) * 2019-12-12 2021-06-17 Abb Power Grids Switzerland Ag Medium frequency transformer with parallel windings

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