KR20000070419A - Method and device in manufacturing a transformer/reactor - Google Patents

Abstract

It has at least one gas-cooled or water-cooled transformer / reactor with a winding, the winding having one high voltage cable 111 and at least one additional member 9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75, and gas-cooled or water-cooled transformers / reactors and their wound around windings 2, 3, 4 disposed around the legs 22, 23, 24 of the transformer / reactor. Manufacturing method.

Description

METHOD AND DEVICE IN MANUFACTURING A TRANSFORMER / REACTOR}

Modern power transformers are mostly oil cooled, with cores consisting of a number of core legs combined with yokes and immersed in oil-filled sealed vessels (primary, secondary, control). Heat generated in the coils and the core is removed by oil circulating internally through the coils and the core, which transfers the heat through the walls of the vessel to the ambient air. The oil circulation may be forced by pumping the oil around or naturally by the temperature difference in the oil. The circulating oil is externally cooled by air or water cooling equipment. External air cooling can be through forced or natural convection. The oil also has insulation in high voltage oil cooled transformers, in addition to acting as a heat carrier.

Dry transformers are usually air-cooled. Since today's dry transformers are used at low power loads, these dry transformers are primarily cooled through natural convection. The technology of the present application is an axial cooling duct formed by a pleated winding disclosed in British Patent No. 1,147,049, an axial duct for cooling winding embedded in a casting resin disclosed in European Patent No. 83107410.9 and Sweden. It relates to the use of cross-current fans at peak loads disclosed in patent 7303919-0.

Cooling needs are greater in cable wound power transformers. Forced convection is required to cool all windings, but natural convection is not enough to cool the windings. It is important that the path of movement of the heat coolant is short and the heat travels efficiently. Therefore, it is important that all windings are in direct contact with a sufficient amount of coolant.

For example, through German patent A1-2854520, a rectifier coil for a rectifier assembly with a coil of resin-embedded, highly flexible plated cable, in particular with a winding cooling duct (a commutation coils are known. However, it is not only a matter of considering a transformer / reactor with a high voltage cable having specific electrical / magnetic problems.

A conductor in which an inner layer and an outer layer of semiconducting pyrolized glassfiber are formed in an insulating portion is known from US Pat. No. 5,036,165. It is also known to form such insulation in the conductors of a dynamo-electric machine, for example in US Pat. No. 5,066,881 two parallel rods in which a semiconductive pyrolytic glass fiber layer forms the conductors. Insulator in the stator slot is surrounded by an outer layer of semiconductive pyrolytic glass fibers. This pyrolytic glass fiber material is described as suitable because it still retains resistivity even after the impregnation treatment.

Purpose of the Invention

It is an object of the present invention to provide a transformer / reactor with one winding in which additional members are fitted in one or more spaces made between each winding of the windings in the winding. Additional members are selected as required, which are cooling tubes for gases or liquids, empty tubes, earthing arrangements, stabilizing compounds, mechanical stabilizers that can be used as needed. ), Noise-suppressing members or various types of transducers.

It is a further object of the present invention to provide a transformer of the type described in the introductory section of the present invention, which can make the cable wound power transformer gas-cooled or preferably water-cooled. The present invention aims to cool each winding in the windings by correctly distributing the coolant to meet the various cooling requirements of the windings.

The present invention also aims to achieve the use of an internal cooling scheme which eliminates the use of an oil cooling scheme in the power transformer, thus resulting in low weight, high filling rates and ultimately cost savings.

Summary of the Invention

The above mentioned objects are achieved by a method and apparatus according to the invention having the features defined in the appended claims.

The present invention relates to a transformer or reactor comprising a single transformer core wound around a cable and having a cooling duct formed between each winding of the cable winding. The cooling duct is also configured to transfer water to cool all cable windings in the transformer.

In the device according to the invention, the windings are preferably in the form corresponding to cables with solid extruded insulators which are used today for power distribution, for example XLPE-cables or EPR-insulators. Such a cable consists of one or more strand parts, one inner semiconducting layer surrounding the conductor, one solid insulating layer surrounding the inner semiconducting layer and one outer semiconducting layer surrounding the insulating layer. It includes one inner conductor configured. Such cables are flexible, and the technique of the device according to the invention is based on one winding system, which is inherently formed of conductors that bend at assembly time, so this flexibility is essential in this regard. Characteristic. XLPE-cables typically have flexibility corresponding to a radius of curvature of approximately 20 cm for cables with a diameter of 30 mm and a radius of curvature of approximately 65 cm for cables with a diameter of 80 mm. In the present application, the term "flexibility" is used for a winding having flexibility with a radius of curvature of about four times the cable diameter, preferably about eight to twelve times the cable diameter.

The windings must be made to retain their properties when bent and thermally stressed during operation. In this relationship, it is very important for the layers to maintain adhesion to each other. Here, the material properties of the layers, in particular the elasticity and relative coefficients of thermal expansion, are crucial. In XLPE-cables, for example, the insulating layer consists of cross-linked low density polyethylene, and the semiconducting layer consists of polyethylene with mixed soot and metal particles. The volume change with temperature changes is fully absorbed as the radius of the cable changes, and since the difference in thermal expansion coefficients for the elasticity of these materials is relatively small, radial expansion can occur without loss of adhesion between the layers.

The combination of materials described above should be recognized by way of example only. Meets the above-mentioned conditions and conditions for becoming semiconducting, that is, those having a resistivity within the range of 10 ⁻¹ to 10 ⁶ ohm-cm, for example, 1 to 500 ohm-cm or 10 to 200 ohm-cm Of course, other combinations are also included in the scope of the present invention.

The insulating layer is, for example, low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), polybutylene (PB), polymethylpentene (PMP), crosslinked polyethylene (XLPE) and ethylene It may be made of a solid thermoplastic such as rubber such as propylene rubber (EPR) or silicone rubber.

The inner and outer semiconducting layers may be made of the same base material, but may include particles of a conductive material such as mixed leaded or metal powder.

The mechanical properties of these materials, in particular the coefficients of thermal expansion, are relatively unaffected, at least within the proportions necessary to achieve the conductivity requirements according to the present invention, whether or not the cast or metal powder is mixed.

Ethylene-vinyl-acetate copolymers / nitrile rubbers, butyl lymph polyethylenes, ethylene-butyl-acrylate-copolymers and ethylene-ethyl-acrylate copolymers also belong to suitable polymers as semiconductors.

Although other types of materials are used as the base in the various layers, it is preferable that the coefficients of thermal expansion of the materials are generally the same. This is the case when the substances listed above are combined.

The materials listed above have a relatively good elasticity with an E-modulus of E <100 MPa, preferably of <200 MPa. The elasticity is sufficient to be absorbed by the elasticity in the radial direction even if there is a small difference between the coefficients of thermal expansion of the materials in the layers, so that no cracks or other damages occur and the layers do not separate from each other. The material of the layers is elastic, and the adhesion between the layers is at least at the same level as the weakest of the materials.

The conductivity of the two semiconducting layers is sufficient to make the potential difference of each layer substantially uniform. The conductivity of the outer semiconducting layer is large enough to include an electric field in the cable, but small enough to not cause a large loss due to the current induced in the longitudinal direction of the layer.

Thus, the two semiconducting layers each essentially constitute one equipotential surface, which substantially surrounds the electric field between them.

Of course, nothing prevents one or more additional semiconducting layers from being placed in the insulating layer.

The cooling tubes according to the invention consist of electrically insulating material, for example cross-linked polyethylene in the form of circular "XLPE tubes" alternating with the cables such that heat is mainly transferred from the cable to the cooling tube via heat conduction. The use of a polymer tube material can avoid problems caused by voltage and eddy currents induced into the tubes. In addition, polymer tubes are considerably more flexible than metal tubes. The polymer tubes do not have to have a circular cross section, but may have a square or other form of cross section in which all the spaces between the four adjacent cables are filled. In order to draw and withdraw each cooling tube or cooling hose into each cable layer, each cable layer is wound at intervals and then connected and connected in series. The space between the cables and the cooling tubes is also filled with a thermally conductive compound.

The transformer core according to the invention can be cooled by water circulating in gas or liquid, eg cooling blocks with air and / or cooling ducts sucked from the fan. Another coolant that can be used is helium.

The present invention also relates to a method of manufacturing a cable wound transformer / reactor and a transformer / reactor produced by the method, which includes various types of transducers, cooling tubes, grounding devices, stabilizing compounds, mechanical stabilizers, noise protection members. Or additional members, such as hollow tubes, may be wound into the winding coils when the cable is wound around the legs of the transformer / reactor. Empty tubes may be equipped with control or measurement windings, additional magnetic material, extra windings, and the like. While these empty tubes are wound, a pulling wire can be used therein.

The present invention relates to a process for producing a gas-cooled or preferably water-cooled cable-wound power transformer and a winding cable power transformer having a voltage range up to 400 kW.

The present invention will be described in more detail with reference to the accompanying drawings.

1 shows a partially cutaway perspective view of a three-phase power transformer according to the present invention.

2 is a cross-sectional view of an iron core coil including four embodiments 2a, 2b, 2c, 2d according to the present invention.

3 shows a cross-sectional view of an iron cored coil comprising further embodiments 3a, 3b, 3c, 3d, 3e, 3f according to the invention.

1 shows a power transformer 1 with three winding coils 2, 3, 4, each comprising one low voltage winding 6 and one high voltage winding 5. Winding coils 2, 3, 4 are wound around iron cored legs 22, 23, 24, respectively, which legs engage with the upper and lower yokes 7, 8 of the iron core on each side of the coils. do. Thus, the legs 22, 23, 24 and the yokes 7, 8 form the iron core of the transformer 1 as a whole.

2 shows a partial cross-sectional view of a power transformer in which high voltage cables 111 are wound for use as transformer windings according to the present invention. The high voltage cable 111 comprises a plurality of copper (Cu) wires 112 having, for example, a circular cross section. These wires 112 are disposed at the center of the high voltage cable 111. The element wires 112 are surrounded by the first semiconducting layer 113. The first semiconducting layer 113 is surrounded by a heat transfer layer 114, for example an XLPE insulator. The insulating layer 114 is surrounded by the second semiconducting layer 115. Therefore, the term "high voltage cable" in the present application does not usually include an enclosure surrounding the distribution cable. The high voltage cable 111 is wound around the leg 24, which is coupled by yoke 7 to the other legs in the transformer.

When the high voltage cable with the cable wound is straight, a space 8 is formed between the cables, as shown in the embodiment according to FIG. 2, which is a cylindrical sheath surface of four adjacent cables 111. That is, it is bounded by the second semiconducting layer 115. The space 8 forms a cooling duct which can use liquid coolant, preferably water, which can be designed in any of the four shown in the figure.

The first embodiment of the transformer labeled 2a is provided with cylindrical cooling tubes 9 (XLPE tubes) made of crosslinked polyethylene, which tubes have a spacing agent 10 which acts as a thermally conductive compound. ) And completely fills the space 8 between the cooling tube 9 and the cylindrical sheath surface of each cable 111.

In a second embodiment of the transformer labeled 2b, it also has square cooling tubes 11 (XLPE tubes) made of crosslinked polyethylene, and is surrounded by a space filler 10 which acts as a thermally conductive compound. The space filler 10 completely fills the space 8 between the cooling tube 11 and each cable 111. The square cooling tube 11 makes better use of the space 8 for cooling purposes.

A third embodiment of the transformer, labeled 2c, is provided with a concave square cooling tube 12, the sides of which have bends such as cylindrical cables. This form further minimizes the space between the cooling tube 12 and the cable as compared to the second embodiment. In addition, the cooling tube 12 in this embodiment is made of crosslinked polyethylene (XLPE tubes), which also serves as a thermally conductive compound that completely fills the space between the cooling tube 12 and each cable 111. Surrounded by filler 10.

In all three embodiments disclosed above, the coolant in the form of coolant flows into each cooling tube 9, 11, 12. However, gaseous coolants such as helium may also be used. The liquid coolant in the tube can be used in other forms.

The fourth embodiment of the transformer, labeled 2d, is equipped with a cylindrical XLPE tube 13 installed side by side inside insert tubes 14 (XLPE tubes) of square cross-linked polyethylene, which is an XLPE tube. The field 13 is surrounded by a space filler inside the insertion tube 14, which also fills the space filler 10 completely filling the space 8 between the cooling tube 9 and each cable 111. Surrounded by) Space filler 10 acts as a thermally conductive compound both inside and outside of insertion tube 14.

In all the embodiments described above, the thermally conductive compound in the form of a space filler consists of one or two components of cured silicon rubber filled with a thermally conductive filler such as aluminum oxide. In the uncured state, it has a fluid property of being liquid (pumpable) at high shear rates and of paste form at rest.

In a first process according to the invention, the compound is first sprayed onto the cables, and then the cooling tube 9, 11, 12 or insertion tube 14 is formed in the groove windings of the cable. It is located in. The compound is again sprayed into the cooling tube 9, 11, 12 or the insertion tube 14 and proceeds in such a way that another winding cable is wound. The winding drum rotates during winding, but may not rotate so that the space filler 10 does not flow out.

In a second process according to the invention, the cured silicone rubber compound is injected or extruded as a space filler around the cooling tube 9, 11, 12 or insertion tube 14. In the cured state, the compound has a consistency (similar to molding clay) that is shaped to fill the space remaining between the cables while the cable is wound.

As shown in FIG. 2, the iron core has one yoke 7 and one leg 24, the yoke having one elongated cooling channel 15.

Since the cooling needs vary with the windings, the flow of liquid in the various cooling tubes also varies accordingly. Fast flow is generally required in tubes located closer to the low voltage winding than to tubes located close to the high voltage winding. To achieve an accurate flow distribution, the tubes can have different diameters or can be connected in different series and parallel combinations.

Polymer cooling tubes can be made from many materials such as polyethylene, polypropylene, polybutylene, polyvinylidene fluoride, polytetrafluoroethylene, and can also be filled or reinforced with elastomers. Among them, high density polyethylene, i.e., HDPE, is preferred because the thermal conductivity increases with increasing density. Polyethylene, if crosslinked by peroxide-splitting, silane cross-linking or radiation cross-linking, increases the ability to withstand pressure at elevated temperatures and simultaneously stresses There is also no risk of stress corrosion.

The tubes must be embedded, otherwise the thermal resistance between the tubes and the cables is too high. To increase heat transfer between the tube and the windings, the space is filled with a crosslinkable molding compound. This compound has a low viscosity and therefore consists of a polymer that can be filled with a high rate of thermally conductive filler before being injected into the space, which is then converted into a non-liquid compound by chemical reaction. Examples of preferred compounds include acrylics, epoxys, unsaturated polyesters, polyurethanes and silicones, the latter being preferred as they are non-toxic. Thermally conductive fillers may also include oxides of aluminum, magnesium, iron or zinc, nitrides of bromine or aluminum and silicon carbide. For example, a mixture of aluminum oxide and silicon, ie polydimethyl siloxane having vinyl groups reacted with hydrogen polydimethyl siloxane under platinum catalyst, is injected into the space between the XLPE tube and the windings at over-pressure, It is then allowed to cure by the hydrogen element added to the vinyl groups.

3 shows a view corresponding to FIG. 2, the cooling tubes are joined or replaced by other types of members. The numbers indicate which other members are suitable to be wound with the high voltage cable 111. The high voltage cable has the same shape as described as the embodiments of FIG. Also, the transformer / reactor core is similar to that shown in FIG.

3a represents one further member in the form of an empty tubular member 50 configured to be wound together with the high voltage cable 111. This tube 50 is also surrounded by one spacer 10, which in this case also acts as a thermally conductive compound but may be endowed with other properties suitable for the further member. The tube 50 is intended to allow insertion of various other components into the winding, such as extra windings for control or measurement. In other embodiments, a magnetic material may be inserted into the tube to change the electrical and / or magnetic properties of the transformer / reactor. It is also possible to stitch extra windings of the same type as the high voltage cable 111 described above. In such a method of inserting the winding, the tube is smoothed with a suitable formulation, for example soapy water. In order to facilitate the insertion of the various components into the tube 50, one or more pulling wires 51 are provided.

Another embodiment is shown as 3b, with additional members arranged as ground member 55. This is elliptical in the figure, but may have other shapes of cross section.

According to another embodiment, shown as 3c in the figure, the additional member is in the form of one stabilizing compound 60, which is more rigid than the peripheral spacer 10 and has one distinct shape even at room temperature upon storage. .

3d represents an embodiment of one additional member in the form of one mechanical stabilizer 65, which may be made in a number of loose arc shapes or in the form of a wound wire.

3e illustrates an embodiment in which an additional member in the form of a noise preventing member 70 in a star shape is provided to absorb mechanical vibrations.

3f represents an embodiment in which an additional member in the form of one electric transducer 75 is wound into a winding. The transducer also includes conductors for connection to calculation, evaluation, and control equipment, although not shown.

The spacer 10 completely fills the space 8 between each additional member and surrounding high voltage cables 111 in all the embodiments described above.

The invention is not limited to the illustrated embodiment. Several variations can be made within the scope of the present invention. The cables do not have to be located symmetrically, as shown in FIGS. 2-3, in which case the spaces between adjacent windings have a different appearance, so that additional members can be made to fit the shape of the space. You must lose.

Claims (37)

A winding comprises one high voltage cable 111 having one insulated electrical lead comprising at least one live lead 112, the high voltage cable also being around the live lead 112. One first layer 113 having semiconductivity disposed on the substrate, one solid insulating layer 114 disposed around the first layer 113, and semiconductivity disposed around the insulating layer 114. And a second layer 115 having at least one wound into the windings 2, 3, 4 when the high voltage cable 111 is wound around the legs 22, 23, 24 of the transformer / reactor. Gas-cooled or water-cooled transformer with at least one winding, characterized in that it is designed to have one additional member 9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75. Method for producing a reactor. 2. A cable according to claim 1, wherein a) the first layer of the cable is wound and b) additional members 9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75 are wound or attached. C) an additional layer of cable is wound, wherein steps b) and c) are repeated until the entire coil is completely wound. The transformer according to claim 1, characterized in that the high voltage cable is wound at the same time as the additional members 9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75 are wound or attached. / Reactor production method. 4. The spacer 10 according to claim 2 or 3, before the additional members 9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75 are wound or attached. Method for producing a transformer / reactor, characterized in that located above. 5. The spacer 10 according to claim 4, wherein after the additional members 9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75 are wound or attached, the spacer 10 is positioned on the winding. Characterized in that the transformer / reactor manufacturing method. 6. Transformers according to claim 1, 2, 3, 4 or 5, characterized in that one cooling tube 9, 11, 12, 13 is wound as an additional member in the winding. Method for producing a reactor. The method of claim 1, 2, 3, 4 or 5, wherein one single tube member 50, one grounding member 55, one stabilizing compound 60, one mechanical Method for producing a transformer / reactor, characterized in that the stabilization device (65), one noise protection member (70) or one electrical transducer (75) is wound as an additional member in the winding. 7. Method according to claim 6, characterized in that water flows through the cooling tubes (9, 11, 12, 13). 9. The thermally conductive compound (10) of claim 8, wherein a) the thermally conductive compound (10) is sprayed between the spaces formed between the windings of the winding after the first layer of cable has been wound up, and b) the additional thermally conductive compound (10) is , Sprayed onto a cooling tube (9, 11, 12) or an insulating tube (14) wound in the spaces formed between the windings of the windings. 9. A cooling tube (9, 11, 12) or insulating tube (14) extruded or embedded with a thermally conductive compound (10), after the first layer of cable has been wound, Wound up, b) when the second layer of cable is wound, the thermally conductive compound (10) is shaped to abut the cables. Having at least one winding wound around the legs 22, 23, 24 of the core, the windings 2, 3, 4 having a single insulated electrical conductor comprising at least one live conductor 112. And a winding thereof are also disposed around the live conductor 112 and having a semiconducting first layer 113 and a solid insulating layer 114 disposed around the first layer 113 and the insulation. At least one additional member 9, 11, 12, 13, 14, comprising a second layer 115 disposed around layer 114 and wound in windings 2, 3, 4. , 50, 55, 60, 65, 70, 75, gas-cooled or water-cooled transformer / reactor. 12. The transformer / reactor according to claim 11, wherein the high voltage cable (111) is cylindrical. The method according to claim 11 or 12, wherein in the winding process, at least one additional member (9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75) is placed between each cable (111). Transformer / reactor, characterized in that located in the formed space (8). 13. The method according to claim 11 or 12, wherein the additional member comprises at least one cooling tube (9, 11, 12, 14) which is located in the space (8) formed between the cables (111) during the winding process. Transformer, characterized in that the space (8) formed between the cooling tubes (9, 11, 12, 14) and the cables is filled with a thermally conductive compound (10). 15. Transformer / reactor according to claim 14, characterized in that one cooling tube (9) having a circular cross section is located in the space (8). 15. Transformer / reactor according to claim 14, characterized in that one cooling tube (11) having a square cross section is located in the space (8). 15. Transformer / reactor according to claim 14, characterized in that one square cooling tube (12) having a concave side is located in the space (8). 15. Transformer / reactor according to claim 14, characterized in that the cooling tube (13) is surrounded by one insertion tube containing filler (10). The method according to claim 11 or 12, wherein the additional member comprises one single tube member 50, one ground member 55, and one stabilizing compound in the space 8 between each cable 111. 60), one mechanical stabilizer (65), one noise prevention member (70) or one electrical transducer (75), and the additional member (50, 55, 60, 65, 70, 75) and Transformer / reactor, characterized in that the space (8) formed between the cables is filled with one thermally conductive compound (10). The method according to claim 14, 15, 16, 17, 18 or 19, wherein the thermally conductive compound 10 has a low viscosity when the shear rate is high, and at a standstill (at rest) in the form of a paste, transformer / reactor. 21. The transformer / reactor of claim 20, wherein the thermally conductive compound consists of one or two component cured silicone rubbers containing a thermally conductive filler. The method of claim 14, 15, 16, 17, 18, 19, 20, or 21, wherein the filler is one of aluminum oxide, boron nitride or silicon carbide. A transformer / reactor, characterized in that consisting of. The method according to claim 14, 15, 16, 17, 18, 20, 21 or 22, wherein the cooling tube 13 is made of polyethylene, polypropene, polyview. A transformer / reactor, characterized in that it is made of a dielectric material such as ten, polyvinylidene fluoride, polytetrafluoroethylene or filled and reinforced elastomers. The method according to claim 14, 15, 16, 17, 18, 20, 21, 22 or 23, wherein the cooling tube 13 is made of high density polyethylene (HDPE). Transformer / reactor, characterized in that The method according to claim 14, 15, 16, 17, 18, 20, 21, 22, 23 or 24, wherein the cooling tube 13, A process for producing a water-cooled transformer / reactor, characterized in that it is made of crosslinked polyethylene (XLPE). Claims 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, and 23 The method of claim 24, wherein the high voltage cable 111 includes a plurality of element wires 112, one inner semiconducting layer 113 surrounding the conductive wires, and an insulating layer 114 surrounding the inner semiconducting layer. And a conductive wire including an outer semiconducting layer (115) surrounding the insulating layer. 27. Transformer / reactor according to claim 26, characterized in that the high voltage cable (111) has a diameter in the range of 20 to 250 mm and a conductive area in the range of 40 to 3000 mm2. Claims 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, and 23 28. Transformer / reactor according to claim 24, 25, 26 or 27, characterized in that the insulated conductor or high voltage cable (111) is flexible. 29. The transformer / reactor according to claim 28, wherein the layers (113, 114, 115) are configured to be joined together even when the insulated conductor or high voltage cable (111) is bent. Claims 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, and 23 30. The method of claim 24, 25, 26, 27, 28 or 29, wherein at least two adjacent layers 113, 114 and 115 of the winding are of approximately the same coefficient of thermal expansion. Characterized in that it has a transformer / reactor. Claims 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26 31. The coolant according to claim 27, 28, 29 or 30, characterized in that all coolant in gas or liquid form designed to cool the transformer / reactor is configured to flow through the cooling tube (13). Made, transformer / reactor. Claims 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, and 23 32. The method of claim 24, 25, 26, 27, 28, 29, 30, or 31, wherein the flexible winding is surrounded by an inner semiconducting layer. A conductive core, an insulating layer of a solid material surrounding the inner semiconducting layer, and an outer semiconducting layer surrounding the insulating layer, wherein the layers are adhered to each other. Claims 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, and 23 33. The method according to claim 24, 25, 26, 27, 28, 29, 30, 31 or 32, in layers with temperature changes in operation. Is made of a material having a relationship between the elasticity and the coefficient of thermal expansion of the layers, so that the change in the volume of is completely absorbed by the change in the diameter of the cable to maintain the adhesion to each other against temperature changes occurring in operation. Made, transformer / reactor. Claims 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, and 23 The method of claim 24, 25, 26, 27, 28, 29, 30, 31, 32 or 33, wherein the material of the layers, A transformer / reactor, characterized in that it has a high elasticity, preferably a stretching coefficient of 500 MPa or less, more preferably a stretching coefficient of 200 MPa or less. Claims 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, and 23 35. The method of claim 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 or 34, wherein the layer Transformer / reactor, characterized in that the coefficient of thermal expansion of the material is approximately the same. Claims 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, and 23 Claims 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 or 35 Wherein the adhesion between the layers is at least about the same as the weakest material. Claims 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, and 23 Claims 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 or 37. The transformer / reactor of claim 36 wherein each semiconducting layer essentially constitutes an equipotential surface.