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WO1998034240A1 - Refroidissement par air axial combine pour transformateur - Google Patents

Refroidissement par air axial combine pour transformateur Download PDF

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Publication number
WO1998034240A1
WO1998034240A1 PCT/SE1998/000161 SE9800161W WO9834240A1 WO 1998034240 A1 WO1998034240 A1 WO 1998034240A1 SE 9800161 W SE9800161 W SE 9800161W WO 9834240 A1 WO9834240 A1 WO 9834240A1
Authority
WO
WIPO (PCT)
Prior art keywords
power transformer
layers
winding
transformer
cooling
Prior art date
Application number
PCT/SE1998/000161
Other languages
English (en)
Inventor
Gunnar Kylander
Mats Leijon
Original Assignee
Asea Brown Boveri Ab
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
Priority claimed from SE9700346A external-priority patent/SE511371C2/sv
Application filed by Asea Brown Boveri Ab filed Critical Asea Brown Boveri Ab
Priority to AU58912/98A priority Critical patent/AU5891298A/en
Priority to JP53280398A priority patent/JP2001509965A/ja
Priority to EP98902358A priority patent/EP0956566A1/fr
Publication of WO1998034240A1 publication Critical patent/WO1998034240A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • H01F27/085—Cooling by ambient air
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/322—Insulating of coils, windings, or parts thereof the insulation forming channels for circulation of the fluid

Definitions

  • the present invention relates to an air-cooled conductor wound power transformer and a procedure for air-cooling a conductor wound power transformer.
  • Today's power transformers are normally oil cooled.
  • the transformers are provided with a core consisting of a number of core legs connected by yokes and windings constituting coils (primary, secondary, regulated) which are immersed in a sealed tank filled with oil.
  • the heat, generated in the coils and core is removed by oil circulating internally through the coil and core and released into the surrounding air via the walls of the vessel.
  • Oil circulation may either be forced by pumping the oil around or it may be natural due to temperature differences in the oil .
  • the circulating oil is cooled externally by air- or water cooling devices. External air-cooling of oil may be forced and/or effected through natural convection.
  • the oil has an insulating function besides its role as conveyer of heat in oil cooled transformers for high voltage.
  • Dry transformers are normally air-cooled. They are normally cooled by natural convection as today's dry transformers are used at low power loading.
  • the present technology related to axial cooling ducts, produced by means of a corrugated winding, is disclosed in GB 1.147.049, axial ducts for the cooling of windings embedded in cast resin is disclosed in EP 83107410.9 or the use of cross flow fans at peak load is disclosed in SE 7303919-0.
  • the need for cooling is greater for a power transformer. Forced convection is necessary to meet the cooling requirements of all windings. Natural convection is not sufficient for cooling the conductor windings. It is important that the heat is transported by short means to the cooling agent and that this is conducted in an effective manner to the cooling agent . It is also important that all windings are in direct contact with a sufficient quantity of cooling agent.
  • a conductor is known through US 5 036 165, in which the insulation is provided with an inner and an outer layer of semiconducting pyrolized glassfiber. It is also known to provide conductors in a dynamo-electric machine with such an insulation, as described in US 5 066 881 for instance, where a semiconducting pyrolized glassfiber layer is in contact with the two parallel rods forming the conductor, and the insulation in the stator slots is surrounded by an outer layer of semiconducting pyrolized glassfiber.
  • the pyrolized glassfiber material is described as suitable since it retains its resistivity even after the impregnation treatment .
  • the object of the invention is to achieve an arrangement, as stated by way of introduction in the above- mentioned, which enables the air-cooling of a cable wound power transformer.
  • a further object of the invention is to provide radial cooling ducts between each layer of cables in which the cooling means is correctly distributed in order to meet the cooling requirements of the cable layers. Cooling of the core and winding is obtained by cooling air flowing axially along the leg of the core whereby an endplate steers the air radially out through horizontal ducts in the winding. The air is distributed in the ducts according to their cooling requirements by varying the height of the horizontal ducts. Disk formed radial ducts are created by spacers which are inserted in the winding during winding of the coil . The cooling flow is produced by means of fans and the spacers are dimensioned such to produce flow in the ducts which meet the individual cooling requirements of the windings.
  • the present invention relates to a power transformer comprising a transformer core which is cable wound, arranged such that the winding is provided with spacers separating each cable turn in the axial direction in order to create disk formed ducts .
  • a first embodiment of the invention comprises hereby radial cooling ducts between each layer of the cable, i.e. each winding turn in the axial direction created by spacers during winding of the coil.
  • This first embodiment comprises also fans in order to transport air through the ducts.
  • the spacers are dimensioned such to produce different pressure resistance and thereby distribute the cooling flow such that the cooling requirements are met for each layer of the cable.
  • the windings are composed of cables having solid, extruded insulation, of a type now used for power distribution, such as XLPE-cables or cables with EPR-insulation .
  • a cable comprises an inner conductor composed of one or more strand parts, an inner semiconducting layer surrounding the conductor, a solid insulating layer surrounding this and an outer semiconducting layer surrounding the insulating layer.
  • Such cables are flexible, which is an important property in this context since the technology for the device according to the invention is based primarily on winding systems in which the winding is formed from cable which is bent during assembly.
  • the flexibility of a XLPE-cable normally corresponds to a radius of curvature of approximately 20 cm for a cable 30 mm m diameter, and a radius of curvature of approximately 65 cm for a cable 80 mm in diameter.
  • the term "flexible" is used to indicate that the winding is flexible down to a radius of curvature in the order of four times the cable diameter, preferably eight to twelve times the cable diameter.
  • Windings in the present invention are constructed to retain their properties even when they are bent and when they are subjected to thermal stress during operation. It is vital that the layers retain their adhesion to each other in this context.
  • the material properties of the layers are decisive here, particularly their elasticity and relative coefficients of thermal expansion.
  • the insulating layer consists of cross-linked, low-density polyethylene
  • the semiconducting layers consist of polyethylene with soot and metal particles mixed in.
  • the insulating lay may consist, for example, of a solid thermoplastic material such as low-density polyethylene (LDPE) , high-density polyethylene (HDPE) , polypropylene (PP), polybutylene (PB), polymethyl pentene (PMP), cross-linked materials such as cross-linked polyethylene (XLPE) , or rubber such as ethylene propylene rubber (EPR) or silicon rubber.
  • LDPE low-density polyethylene
  • HDPE high-density polyethylene
  • PP polypropylene
  • PB polybutylene
  • PMP polymethyl pentene
  • cross-linked materials such as cross-linked polyethylene (XLPE)
  • EPR ethylene propylene rubber
  • the inner and outer semiconducting layers may be of the same basic material but with particles of conducting material such as soot or metal powder mixed in.
  • the mechanical properties of these materials are affected relatively little by whether soot or metal powder is mixed in or not - at least in the proportions required to achieve the conductivity necessary according to the invention.
  • the insulating layer and the semiconducting layers thus have substantially the same coefficients of thermal expansion.
  • Ethylene-vinyl-acetate copolymers/nitrile rubber, butyl graft polyethylene, ethylene-butyl-acrylate-copolymers and ethylene-ethyl-acrylate copolymers may also constitute suitable polymers for the semiconducting layers. Even when different types of material are used as base in the various layers, it is desirable for their coefficients of thermal expansion to be substantially the same. This is the case with combination of the materials listed above.
  • the materials listed above have relatively good elasticity, with an E-modulus of E ⁇ 500 MPa, preferably ⁇ 200 MPa.
  • the elasticity is sufficient for any minor differences between the coefficients of thermal expansion for the materials in the layers to be absorbed in the radial direction of the elasticity so that no cracks or other damage appear and so that the layers are not released from each other.
  • the material in the layers is elastic, and the adhesion between the layers is at least of the same magnitude as the weakest of the materials.
  • the conductivity of the two semiconducting layers is sufficient to substantially equalize the potential along each layer.
  • the conductivity of the outer semiconducting layer is sufficiently large to contain the electrical field in the cable, but sufficiently small not to give rise to significant losses due to currents induced in the longitudinal direction of the layer.
  • each of the two semiconducting layers essentially constitutes one equipotential surface, and these layers will substantially enclose the electrical field between them. There is, of course, nothing to prevent one or more additional semiconducting layers being arranged in the insulating layer.
  • Figure 2 shows the embodiment in Figure 1 as a top view having horizontal radial ducts formed by radial spacers;
  • Figure 3 shows schematically a radial view through the embodiment according to Figure 1 having a fan arrangement according to the invention
  • Figure 4 shows a view through a high voltage cable according to the invention.
  • Figure 1 shows in an axial view a part of a three phase power transformer 1 provided with windings 2, so called disk windings, constituting coils having cooling ducts 3 in the form of disks which are achieved by placing spacers 4 to radially extend between each winding turn which is arranged axially.
  • the winding is furthermore sealed off against a lower end plate 6.
  • the winding coil may also be sealed off against the upper end of an upper winding disk 7 and against the lower end of a lower winding disk 8.
  • the Figure shows furthermore a part of an iron core of the transformer, the part constituting its leg 9.
  • the end plate 6 is used as a sealing means between the leg 9 of the core and the lower winding disk 8.
  • the principle concerning the cooling of windings of this embodiment is that air is forced axially along the iron core and thereafter distributed radially among the horizontal disk formed cooling ducts 3 formed by radial spacers 4 since the lower end of the winding coil is sealed off in order to force the air flow radially out through the windings.
  • the spacers 4 are placed around a hypothetical circular cross- section between two winding turns. The spacers are inserted during winding of the coil . It is furthermore required in this embodiment that a fan be mounted for each coil . The air may hereby be sucked or forced through the coil .
  • Figure 2 shows a top view of the invention whereby the windings 2 are provided with spacers 4 placed radially in the form of a spoke, forming radial cooling ducts 14 in the form of a cake .
  • the spacers 4 are arranged by dividing eight radial spacers 4 to each disk formed cooling duct 3.
  • One disk formed cooling duct 3 consists thus of eight radial cooling ducts 14 in the form of a cake. All the disk formed cooling ducts 3 are connected to an axial cooling duct 15 formed around the periphery of the leg 9.
  • the spacers 4 are furthermore radially extended. The form of and the material of the spacers is of less importance from a cooling point of view.
  • FIG. 3 shows an arrangement of a fan 10 connected to the inner axial cooling duct 15.
  • the fan is connected by means of a fan hood 16 which is positioned against the inner side of an upper end plate 20 or against the upper winding disk 7 in a contact ring 17.
  • the axial cooling duct 15 constitutes a space between the leg 9 of the core and the upper winding disk 7. By forcing air through the windings it is transported first through the axial cooling duct 15 and is then pressed out through the disk formed cooling ducts 3.
  • the transformer in the embodiment shown in Figure 3 is further provided with a base plate 18 on which the windings rest, which base plate 18 acts as a sealing means against the leg 9 of the core at the end of the coil in such a way that the air is forced to be distributed in the disk formed cooling ducts 3.
  • the coil of the transformer is also limited by the upper end plate 20 which seals off the axial air flow.
  • the cooling ducts have different cooling requirements and are therefore dimensioned differently to produce different pressure resistance and thereby distribute the cooling flow correctly.
  • FIG 4 shows a view in cross section of a high voltage cable 111 to be used as a transformer winding according to the present invention.
  • the high voltage cable 111 comprises a plurality of strands 112 with circular cross- section of for example copper (Cu) . These strands 112 are arranged in the centre of the high voltage cable 111.
  • a first semiconducting layer 113 Around the strands 112 there is arranged a first semiconducting layer 113.
  • an insulating layer 114 of for example XLPE- insulation.
  • the concept of a high voltage cable in the present application does not comprise the outer shielding screen that normally surrounds such a cable for power distribution.
  • the high voltage cable has a diameter in the interval 20 - 250 mm and a conductor area in the interval of 40 - 3000 mm 2 .
  • the invention is not limited to the shown examples because several variations are possible within the framework of the invention.
  • a fan is therefore not required for each coil.
  • An arrangement with a fan which provides all three coils with the necessary amount of air is also feasible.
  • the air may be either sucked or forced through the coil in order to achieve the desired cooling.
  • spacers are subject to variation for neither their shape nor their numbers need be determined in order to obtain the right cooling.
  • the spacers described in the first embodiment need not entirely cover the winding radially but may be placed in several ways. They need not either, as described in the second embodiment, be extended in the entire radial direction for this may be achieved in several other ways .
  • Another modification is to arrange a variable-speed control of the fans with the aid of temperature detectors in order to enable a variable cooling requirement depending on the load of the transformer.
  • a mantle casing may also be arranged in several other ways to the above-mentioned embodiments.
  • the upper and the lower winding disk may be used as an outer casing which acts as a seal and the outside may be cooled by natural convection whereas the upper winding parts are cooled by air flowing radially.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transformer Cooling (AREA)
  • Coils Of Transformers For General Uses (AREA)

Abstract

Cette invention se rapporte à un transformateur de courant (1), qui comprend un noyau, lequel est formé par l'enroulement d'un câble haute-tension (111) qui est souple et qui est composé d'un noyau électroconducteur entouré par une couche semi-conductrice interne (113), par une couche isolante (114) d'un matériau solide entourant la couche semi-conductrice interne (113) et par une couche semi-conductrice externe (115) entourant la couche isolante (114), ces couches (113, 114, 115) adhérant les unes aux autres. L'enroulement (2) en question comporte des éléments d'espacement (4) qui sont disposés de façon à séparer chaque spire de câble dans le sens axial, afin de créer des couduits de refroidissement (3) formés par des disques.
PCT/SE1998/000161 1997-02-03 1998-02-02 Refroidissement par air axial combine pour transformateur WO1998034240A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AU58912/98A AU5891298A (en) 1997-02-03 1998-02-02 Combined axial air-cooling of a transformer
JP53280398A JP2001509965A (ja) 1997-02-03 1998-02-02 軸方向空冷を組み合わせた変圧器
EP98902358A EP0956566A1 (fr) 1997-02-03 1998-02-02 Refroidissement par air axial combine pour transformateur

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
SE9700346A SE511371C2 (sv) 1997-02-03 1997-02-03 Krafttransformator samt förfarande för luftkylning av en sådan
SE9700346-1 1997-02-03
SE9704420A SE9704420D0 (sv) 1997-02-03 1997-11-28 Kombinerad axiell luftkylning i en transformator
SE9704420-0 1997-11-28

Publications (1)

Publication Number Publication Date
WO1998034240A1 true WO1998034240A1 (fr) 1998-08-06

Family

ID=26662872

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1998/000161 WO1998034240A1 (fr) 1997-02-03 1998-02-02 Refroidissement par air axial combine pour transformateur

Country Status (5)

Country Link
EP (1) EP0956566A1 (fr)
JP (1) JP2001509965A (fr)
AU (1) AU5891298A (fr)
SE (1) SE9704420D0 (fr)
WO (1) WO1998034240A1 (fr)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6873080B1 (en) 1997-09-30 2005-03-29 Abb Ab Synchronous compensator plant
US6891303B2 (en) 1996-05-29 2005-05-10 Abb Ab High voltage AC machine winding with grounded neutral circuit
US6894416B1 (en) 1996-05-29 2005-05-17 Abb Ab Hydro-generator plant
US6970063B1 (en) 1997-02-03 2005-11-29 Abb Ab Power transformer/inductor
US6972505B1 (en) 1996-05-29 2005-12-06 Abb Rotating electrical machine having high-voltage stator winding and elongated support devices supporting the winding and method for manufacturing the same
US6995646B1 (en) 1997-02-03 2006-02-07 Abb Ab Transformer with voltage regulating means
US7019429B1 (en) 1997-11-27 2006-03-28 Asea Brown Boveri Ab Method of applying a tube member in a stator slot in a rotating electrical machine
US7046492B2 (en) 1997-02-03 2006-05-16 Abb Ab Power transformer/inductor
US7045704B2 (en) 2000-04-28 2006-05-16 Abb Ab Stationary induction machine and a cable therefor
US7061133B1 (en) 1997-11-28 2006-06-13 Abb Ab Wind power plant
US7141908B2 (en) 2000-03-01 2006-11-28 Abb Ab Rotating electrical machine
CN101625921A (zh) * 2008-07-09 2010-01-13 艾默生网络能源系统北美公司 磁性器件、磁性器件配置方法及开关电源
EP2169692A1 (fr) 2008-09-26 2010-03-31 Bruker Biospin SA Transformateur élévateur de puissance haute tension sans injection d'eau et unité d'alimentation comprenant au moins un tel transformateur
CN102290217A (zh) * 2011-05-04 2011-12-21 广东海鸿变压器有限公司 悬挂式安装的c级立体卷铁心干式变压器线圈

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1304451A (en) * 1919-05-20 Locke h
US5036165A (en) * 1984-08-23 1991-07-30 General Electric Co. Semi-conducting layer for insulated electrical conductors

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1304451A (en) * 1919-05-20 Locke h
US5036165A (en) * 1984-08-23 1991-07-30 General Electric Co. Semi-conducting layer for insulated electrical conductors

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6972505B1 (en) 1996-05-29 2005-12-06 Abb Rotating electrical machine having high-voltage stator winding and elongated support devices supporting the winding and method for manufacturing the same
US6891303B2 (en) 1996-05-29 2005-05-10 Abb Ab High voltage AC machine winding with grounded neutral circuit
US6894416B1 (en) 1996-05-29 2005-05-17 Abb Ab Hydro-generator plant
US6906447B2 (en) 1996-05-29 2005-06-14 Abb Ab Rotating asynchronous converter and a generator device
US6919664B2 (en) 1996-05-29 2005-07-19 Abb Ab High voltage plants with electric motors
US6936947B1 (en) 1996-05-29 2005-08-30 Abb Ab Turbo generator plant with a high voltage electric generator
US6995646B1 (en) 1997-02-03 2006-02-07 Abb Ab Transformer with voltage regulating means
US6970063B1 (en) 1997-02-03 2005-11-29 Abb Ab Power transformer/inductor
US7046492B2 (en) 1997-02-03 2006-05-16 Abb Ab Power transformer/inductor
US6873080B1 (en) 1997-09-30 2005-03-29 Abb Ab Synchronous compensator plant
US7019429B1 (en) 1997-11-27 2006-03-28 Asea Brown Boveri Ab Method of applying a tube member in a stator slot in a rotating electrical machine
US7061133B1 (en) 1997-11-28 2006-06-13 Abb Ab Wind power plant
US7141908B2 (en) 2000-03-01 2006-11-28 Abb Ab Rotating electrical machine
US7045704B2 (en) 2000-04-28 2006-05-16 Abb Ab Stationary induction machine and a cable therefor
CN101625921A (zh) * 2008-07-09 2010-01-13 艾默生网络能源系统北美公司 磁性器件、磁性器件配置方法及开关电源
EP2169692A1 (fr) 2008-09-26 2010-03-31 Bruker Biospin SA Transformateur élévateur de puissance haute tension sans injection d'eau et unité d'alimentation comprenant au moins un tel transformateur
US8085122B2 (en) 2008-09-26 2011-12-27 Bruker Biospin Sa High voltage step-up dry power transformer and power supply unit comprising at least one such transformer
CN102290217A (zh) * 2011-05-04 2011-12-21 广东海鸿变压器有限公司 悬挂式安装的c级立体卷铁心干式变压器线圈
CN102290217B (zh) * 2011-05-04 2012-08-22 广东海鸿变压器有限公司 悬挂式安装的c级立体卷铁心干式变压器线圈

Also Published As

Publication number Publication date
SE9704420D0 (sv) 1997-11-28
EP0956566A1 (fr) 1999-11-17
AU5891298A (en) 1998-08-25
JP2001509965A (ja) 2001-07-24

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