Patent EA-001726-B1 (EA)
Title: Transformer/reactor and method manufacturing thereof
Inventor: LEIJON MATS
IPC: H01F27/16
Filed: 1998-02-02
Abstract: 1. Method of manufacturing a gas or water-cooled transformer/reactor having at least one winding, characterized in that the winding comprises a high-voltage cable (111) having an insulated electric conductor comprising at least one live conductor (112), also comprising a first layer (113) with semiconducting properties arranged surrounding the live conductor (112), a solid insulating layer (114) arranged surrounding said first layer (113), and a second layer (115) with semiconducting properties arranged surrounding the insulating layer (114), and in that the transformer/reactor is designed with at feast one additional member (9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75) which is wound into the winding (2, 3, 4) when the high-voltage cable (111) is wound around the legs (22, 23, 24) of the transformer/reactor. 2. Method as claimed in claim 1, characterized in that a) a first layer of cable is wound, b) additional members (9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75) are wound on or applied, c) an additional layer of cable is wound, whereupon steps b) and c) are repeated until the entire coil is fully wound. 3. Method as claimed in 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 being wound on or applied. 4. Method as claimed in any of claims 2-3, characterized in that spacers (10) are placed on the winding before the additional members (9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75) are wound on or applied. 5. Method as claimed in claim 4, characterized in that spacers (10) are also placed on the winding after the additional members (9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75) have been wound on or applied. 6. Method as claimed in any of claims 1-5, characterized in that a cooling tube (9, 11, 12, 13) is wound as additional member in the winding. 7. Method as claimed in any of claims 1-5, characterized in that a single tubular member (50), an earthing member (55), a stabilizing compound (60), a mechanical stabilizer (65), a noise-suppressing member (70) or an electric transducer (75) is wound in as additional member in the winding. 8. Method as claimed in claim 6, characterized in that water flows through the cooling tube (9, 11, 12, 13). 9. Method as claimed in claim 8, characterized in that  a) a thermally conducting compound (10) is sprayed between the spaces formed between the turns of the winding after the first layer of cable has been wound, b) additional thermally conducting compound (10) is sprayed onto the cooling tube (9, 11, 12) or insulating tube (14) after the cooling tube (9, 11, 12) or insulating tube (14) has been wound in the spaces formed between the winding turns. 10. Method as claimed in claim 8, characterized in that  a) a cooling tube (9, 11, 12) or an insulating tube (14) which has been extruded or embedded in a thermally conducting compound (10) is wound onto the cable after the first layer of cable has been wound, b) the thermally conducting compound (10) is shaped to abut the cables when the second layer of cable is wound another turn. 11. Gas or water-cooled transformer/reactor (1) having at least one winding wound around the legs (22, 23, 24) of the transformer/reactor, characterized in that the winding (2, 3, 4) is performed using an insulated electric conductor comprising at least one live conductor (112), also comprising a first layer (113) with semiconducting properties arranged surrounding the live conductor, a solid insulating layer (114) arranged surrounding said first layer (113), and a second layer (115) with semiconducting properties arranged surrounding the insulating layer (114)) and in that the device comprises at least one additional member (9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75) wound into the winding (2, 3, 4). 12. Transformer/reactor as claimed in claim 11, characterized in that the high-voltage cable (111) is cylindrical in shape. 13. Transformer/reactor as claimed in any of claims 11-12, characterized in that at least one additional member (9, 11, 12, 13, 14, 50, 55, 60, 65, 70, 75) is placed in the space (8) formed between each cable (111) during the winding procedure. 14. Transformer/reactor as claimed in any of claims 11-12, characterized in that the additional member consists of at least one cooling tube (9, 11, 12, 14) placed in a space (8) formed between each cable (111) during the winding procedure, the space (8) that remains between the cooling tubes (9, 11, 12, 14) and the cables being filled with a thermally conducting compound (10). 15. Transformer/reactor as claimed in claim 14, characterized in that a cooling tube (9) with circular cross section is placed in the space (8). 16. Transformer/reactor as claimed in claim 14, characterized in that a cooling tube (11) with quadratic cross section is placed in the space (8). 17. Transformer/reactor as claimed in claim 14, characterized in that a quadratic cooling tube (12) with concave sides is placed in the space (8). 18. Transformer/reactor as claimed in claim 14, characterized in that the cooling tube (13) is surrounded by an insert tube containing filler (10). 19. Transformer/reactor as claimed in any of claims 11-12, characterized in that the additional member consists of a single tubular member (50), an earthing member (55), a stabilizing compound (60), a mechanical stabilizer (65), a noise-suppressing member (70) or an electric transducer (75) in a space (8) between each cable (111), the space (8) that remains between the additional member (50, 55, 60, 65, 70, 75) and the cables being filled with a thermally conducting compound (10). 20. Transformer/reactor as claimed in any of claims 14-19, characterized in that the thermally conducting compound (10) has low viscosity at high shear rate and is in paste form at rest. 21. Transformer/reactor as claimed in claim 20, characterized in that the thermally conducting compound (10) consists of a one or two-component curing silicon rubber provided with a heat-conducting filler. 22. Transformer/reactor as claimed in any of claims 14-21, characterized in that the filler consists of either aluminium oxide, boron nitride or silicon carbide. 23. Transformer/reactor as claimed in any of claims 14-18 or 20-22, characterized in that the cooling tube (13) is made of dielectric material such as polyethylene, polypropene, polybutene, polyvinylidene fluoride, polytetrafluoroethylene or filled and reinforced elastomers. 24. Transformer/reactor as claimed in any of claims 14-18 or 20-23, characterized in that the cooling tube (13) is manufactured from high-density polyethylene (HDPE). 25. Transformer/reactor as claimed in any of claims 14-18 or 20-24, characterized in that the cooling tube (13) is manufactured from cross-linked polyethylene (XLPE). 26. Transformer/reactor as claimed in any of claims 11-25, characterized in that the high-voltage cable (111) is of a type comprising a conductor with a plurality of strand parts (112), a semiconducting layer (113) surrounding the conductor, an insulating layer (114) surrounding the inner semiconducting layer, and an outer semiconducting layer (115) surrounding the insulating layer. 27. Transformer/reactor as claimed in claim 26, characterized in that the high-voltage cable (111) has a diameter in the range of 20-250 mm and a conducting area in the range of 40-3000 mm<2>. 28. Transformer/reactor as claimed in any of claims 11-27, characterized in that the insulated conductor or high-voltage cable (111) is flexible. 29. Transformer/reactor as claimed in claim 28, characterized in that the layers (113, 114, 115) are arranged to adhere to each other even when the insulated conductor or high-voltage cable (111) is bent. 30. Transformer/reactor as claimed in any of claims 11-29, characterized in that at least two adjacent layers (113, 114, 115) of the winding have coefficients of thermal expansion of substantially the same magnitude. 31. Transformer/reactor as claimed in any of claims 14-30, characterized in that all coolant, in the form of gas or liquid, designed to cooling the transformer/reactor is arranged to flow through the cooling tube (13). 32. Transformer/reactor as claimed in any of claims 11-31, characterized in that the winding is flexible and comprises an electrically conducting core surrounded by an inner semiconducting layer, an insulating layer of solid material surrounding the inner semiconducting layer, and an outer semiconducting layer surrounding the insulating layer, which layers adhere to each other. 33. Transformer/reactor as claimed in any of claims 11-32, characterized in that said layers are of materials having such elasticity and such relation between their coefficients of thermal expansion that the fluctuations in volume in the layers caused by temperature fluctuations during operation can be absorbed by the elasticity of the materials so that the layers retain their adhesion to each other at the temperature fluctuations occurring during operation. 34. Transformer/reactor as claimed in any of claims 11-33, characterized in that the materials in said layers have high elasticity, preferably with an E-modulus of less than 500 MPa, more preferably less than 200 MPa. 35. Transformer/reactor as claimed in any of claims 11-34, characterized in that the coefficients of thermal expansion of the materials in said layers are of substantially the same magnitude. 36. Transformer/reactor as claimed in any of claims 11-35, characterized in that the adhesion between the layers is of at least the same order of magnitude as in the weakest of the materials. 37. Transformer/reactor as claimed in any of claims 11-36, characterized in that each semiconducting layer essentially constitutes an equipotential surface.