Rotating electrical machine having high-voltage stator winding and elongated support devices supporting the winding and method for manufacturing the same

• US 6,972,505 B1
• Filed: 05/27/1997
• Issued: 12/06/2005
• Est. Priority Date: 05/29/1996
• Status: Expired due to Fees

• Current Assignee: ABB AB (ABB Limited)
• Original Assignee: ABB (ABB Limited)
• Inventors: Johansson, Leif, Hernnas, Bo, Ivarson, Claes, Backlund, Alberti, Goran, Bengt, Templin, Peter, Leijon, Mats, Rydholm, Bengt, Gertmar, Lars, Rothman, Bengt, Carstensen, Peter, Larsson, Bertil, Holmstrom, Goran
• Primary Examiner(s): MULLINS, BURTON S
• Application Number:
  US09/147,325
• Time in Patent Office: 3,115 Days
• Field of Search: 310/215, 310179-180, 310/184, 310195-196, 310198-208, 310/254, 174DIG 13- 33
• US Class Current: 310/196
• CPC Class Codes: H01F 27/288 Shielding
• CPC Class Codes: H02K 15/00 Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
• CPC Class Codes: H02K 2203/15 Machines characterised by cable windings, e.g. high-voltage cables, ribbon cables
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32
• CPC Class Codes: H02K 3/40 for high voltage, e.g. affording protection against corona discharges
• CPC Class Codes: H02K 3/48 in slots
• CPC Class Codes: H02K 9/197 in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator
• CPC Class Codes: Y10S 174/20 Stator
• CPC Class Codes: Y10S 174/27 including a semiconductive layer
• CPC Class Codes: Y10S 174/33 Method of cable manufacture, assembly, repair, or splicing

Abstract

A rotating electrical machine and method for making the machine, where the machine includes a high-voltage stator winding and elongated support devices for supporting the winding. The machine and method employ an arrangement of cable that is made of inner conductive strands, covered with a first semiconducting layer, which is covered with an insulating layer, which is covered with a second semiconducting layer. The cable is wound in slots in the stator such that separate cable lead-throughs are positioned in specific arrangements with respect to each other and in slots of the stator. The arrangement of the cable in the stator protects the integrity of the respective components in the cable and particularly the second semiconducting layer.

Claims

1. A rotating electric machine configured to operate at high-voltages comprising:

a stator having,

a first slot, a second slot, and a third slot;

a stator winding of a high-voltage cable drawn though said first slot, said second slot, and said third slot of said stator, said high-voltage cable having

an insulation system including

a first semiconducting layer,

a solid insulation layer arranged to surround and be in electrical contact with said first semiconducting layer, and

a second semiconducting layer arranged to surround and be in contact with said solid insulation layer, said second semiconductor layer being formed from an extruded material that is configured to protect said stator winding from being damaged when drawn through said first slot, said second slot, and said third slot; and

a support member positioned in contact with said stator winding, wherein

said first semiconducting layer and said second semiconducting layer are configured to provide respective equipotential surfaces.

2. The machine of claim 1, wherein:

at least one of said first semiconducting layer and said second semiconducting layer has a same coefficient of thermal expansion as the solid insulation layer.

3. The machine of claim 1, wherein:

at least one of said first slot, said second slot, and said third slot has a cable lead-through portion of said high-voltage cable disposed therein;

said support member being arranged in at least one of said first slot, said second slot, and said third slot in resilient fixation with the cable lead-through and configured to exert a pressure against said cable lead-through;

said support member being disposed between said cable lead-through and a side wall of the at least one of said first slot, said second slot, and said third slot;

a spring material being positioned between the cable lead-through and the side wall of said at least one of said first slot, said second slot, and said third slot; and

said support member and said spring material are formed as an elongated pressure element running in a same direction as the cable lead-through.

4. The machine of claim 3, further comprising:

a cable output configured to be directly connected to a power network without an intermediate transformer therebetween.

5. The machine of claim 3, wherein:

said support member comprises a tube having a sleeve containing a pressure-hardened material.

6. The machine of claim 3, wherein:

said pressure-hardened material being an epoxy.

7. The machine of claim 3, wherein:

said support member comprises a tube having a sleeve containing a pressurized fluid.

8. The machine of claim 3, further comprising:

additional elongated pressure elements, wherein

at least a majority of said elongated pressure element and said additional elongated pressure elements are configured to exert pressure on said cable lead-through and an adjacent cable lead-through.

9. The machine of claim 3, wherein:

an axial section of at least one of said first slot, said second slot, and said third slot having a profile with a varying cross-section in which, said side wall and an opposing side wall immediately opposite the cable lead-through each have,

a circular portion that corresponds to an outer diameter of the high-voltage cable, and

a waist portion, being more narrow than said circular portion, and said elongated pressure element being disposed in said waist portion.

10. The machine of claim 9, wherein:

said axial section includes another waist portion being a single-sided waist portion defined on said side wall by a tangential plane to said circular portion and the opposing side wall and a connecting plane situated between and substantially parallel to a corresponding tangential plane and a plane connecting respective centers of the circular portion for the side wall and the opposing side wall, and

said elongated pressure element being arranged at the side wall constituting the tangential plane.

11. The machine of claim 3, wherein:

said elongated pressure element, and another elongated pressure element, being arranged on a same side wall of the at least one of said first slot, said second slot, and said third slot.

12. The machine of claim 3, wherein:

said elongated pressure member and said spring material being arranged close to a same wall of said at least one of said first slot, said second slot, and said third slot, said spring material being joined to the elongated pressure element.

13. The machine of claim 12, wherein:

said spring material including a pad of elastic material applied on the support member.

14. The machine of claim 13, wherein:

said pad has a slot formed therein.

15. The machine of claim 3, wherein:

said elongated pressure element and said spring material being respectively positioned close to different walls of the at least one of said first slot, said second slot, and said third slot.

16. The machine of claim 15, wherein said spring member being of a sheet of elastic material.

17. The machine of claim 16, wherein:

the sheet of elastic material includes slots formed therein.

18. The machine of claim 16, wherein said elastic material comprises rubber.

19. The machine of claim 1, wherein:

a corrugated sheet surrounds at least a portion of the cable lead-through in at least one of said first slot, said second slot, and said third slot.

20. The machine of claim 19, wherein:

the corrugated sheet surrounds the high-voltage cable continuously around an entire circumference of the high-voltage cable and along an entire axial length of the high-voltage cable in the at least one of said first slot, said second slot, and said third slot.

21. The machine of claim 19, wherein:

a largest diameter of the corrugated sheet being substantially equal to a width of the at least one of said first slot, said second slot, and said third slot; and

a depth of a corrugation in said corrugated sheet being sufficient to absorb a thermal expansion of the high-voltage cable during operation of the machine.

22. The machine of claim 19, wherein:

the corrugated sheet being formed from an elastically deformable material.

23. The machine of claim 19, further comprising:

a casting compound disposed between the corrugated sheet and the at least one of said first slot, said second slot, and said third slot.

24. The machine of claim 19, wherein:

the corrugated sheet being formed from a separate tubular corrugated sheet applied around the second semiconducting layer, said second semiconducting layer being an outer semiconducting layer of the high-voltage cable.

25. The machine of claim 24, wherein:

corrugations formed on the corrugated sheet being annular corrugations.

26. The machine of claim 19, wherein:

a surface of said corrugated sheet having corrugations formed in the second semiconducting layer of the high-voltage cable, said second semiconducting layer being an outer semiconducting layer.

27. The machine of claim 26, wherein:

the corrugations in the second semiconducting layer being oriented in a longitudinal direction of the high-voltage cable.

28. The machine of claim 1, wherein:

said support member includes an elongated elastic support element arranged along and in contact with a cable lead-through of said high-voltage cable disposed in said first slot, said second slot, and said third slot.

29. The machine of claim 28, wherein:

the support member shaped to extend along an entire axial extension of the stator.

30. The machine of claim 28, wherein:

the support member being a hose.

31. The machine of claim 30, wherein:

the hose encloses a pressure medium.

32. The machine of claim 31, wherein:

the pressure medium being a fluid.

33. The machine of claim 31, wherein:

the hose being sealed at both ends thereof.

34. The machine of claim 32, wherein:

the fluid of the pressure medium being configured to communicate with a pressure source.

35. The machine of claim 31, wherein:

the pressure medium consists of an elastic material in a solid form.

36. The machine of claim 35, wherein:

the elastic material having a cavity running axially therethrough.

37. The machine of claim 36, wherein:

the cavity having a non-circular cross-section.

38. The machine of claim 35, wherein the pressure medium comprises silicon rubber.

39. The machine of claim 38, wherein:

said slot in a radial plane having a profile with respective wide parts and narrow parts alternating in a radial direction.

40. The machine of claim 39, wherein:

the narrow parts being asymmetrically positioned in relation to a central plane running radially through at least one of said first slot, said second slot, and said third slot.

41. The machine of claim 40, wherein:

respective of the narrow parts being mere-inverted in relation to a nearest adjacent narrow part of the respective narrow parts when viewed in a direction of the radial plane.

42. The machine of claim 38, wherein:

said support element abuts the cable lead-through and an adjacent cable lead-through of the stator winding.

43. The machine of claim 3, wherein said support member comprises a tube having a sleeve containing a pressure medium in solid form.

44. The machine of claim 43, wherein said pressure medium comprises silicon rubber.

45. The machine of claim 43, wherein said pressure medium in solid form includes a cavity running axially therethrough.

46. A rotating electric machine configured to operate at high-voltages comprising:

a high-voltage magnetic circuit having,

a magnetic core, and

a stator winding of a high-voltage cable, said high-voltage cable having,

a conductor configured to carry electrical current and having respective strands,

an inner semiconducting layer arranged to surround and be in contact with said conductor,

a solid insulation layer arranged to surround and be in contact with said inner semiconducting layer, and

an outer semiconducting layer arranged to surround and be in contact with said solid insulation layer, said second semiconductor layer being formed from an extruded material that is configured to protect said stator winding from being damaged when drawn through said first slot, said second slot, and said third slot; and

a support member positioned along and in contact with said stator winding.

47. The machine according to claim 46, wherein:

said magnetic core includes a first slot, a second slot, and a third slot in which said high-voltage cable of said stator winding is disposed;

said inner semiconducting layer and said outer semiconducting layer being configured to provide respective equipotential surfaces.

48. A method for manufacturing a rotating electric machine configured to operate at high-voltages, comprising the steps of:

forming a winding for a stator by positioning a cable in a first slot, a second slot, and a third slot of the stator, said cable being configured to hold a high-voltage and having

an insulation system including

a first semiconducting layer,

a solid insulation layer arranged to surround and be in contact with. said first semiconducting layer, and

a second semiconducting layer arranged to surround and be in contact with said solid insulation layer, said second semiconductor layer being formed from an extruded material that is configured to protect said stator winding from being damaged when drawn through said first slot, said second slot, and said third slot, said first semiconducting layer and said second semiconducting layer providing respective equipotential surfaces; and

inserting an elongated support member axially in at least one of said first slot, said second slot, and said third slot and in contact with said cable.

49. The method of claim 48, wherein:

said inserting step comprises

inserting a hose-like element as said elongated support element in the at least one of said first slot, said second slot, and said third slot; and

filling the hose-like element with a pressure medium.

50. The method of claim 49, wherein:

said filling step comprises filling the hose-like element with a curable material; and

hardening the curable material under pressure.

51. The method of claim 49, wherein:

said filling step, comprises filling said hose-like element with epoxy.

52. The method of claim 49, wherein:

said inserting step comprises inserting said hose-like element after said cable has been inserted in said at least one of said first slot, said second slot, and said third slot.

53. The method of claim 49, wherein:

said inserting step comprises inserting said hose-like element in said at least one of said first slot, said second slot, and said third slot, and in at least another slot in a forwards and backwards pattern.

54. The method of claim 48, further comprising:

surrounding the cable with a corrugated sheath before inserting the cable into the at least one of said first slot, said second slot, and said third slot.

55. The method of claim 54, wherein said surrounding step comprises applying a separate tubular corrugated sheet around the cable before inserting the cable into the at least one of said first slot, said second slot, and said third slot.

56. The method of claim 55 wherein said surrounding step comprises applying a lubricant on the cable in an axial direction.

57. The method of claim 54, wherein:

said surrounding step comprises surrounding the corrugated sheath by applying a separate tubular corrugated sheath in the at least one of said first slot, said second slot, and said third slot before inserting the cable into the at least one of said first slot, said second slot, and said third slot.

58. The method of claim 54, further comprising the step of:

inserting a casting compound between the corrugated sheath and a wall of the at least one of said first slot, said second slot, and said third slot.

59. The method of claim 58, further comprising the step of:

casting axial cooling tubes in the casting compound.

60. The method of claim 54, wherein said surrounding step, comprises surrounding the cable with the corrugated sheath, wherein said corrugated sheath includes annular corrugations.

61. The method of claim 54, wherein said step of surrounding comprises surrounding a cable with the corrugated sheath having annular corrugations that run in a helical direction.

62. The method of claim 54, wherein:

said surrounding step comprises surrounding the cable with the second semiconducting layer as an outer semiconducting layer, said second semiconducting layer having corrugations; and

said corrugated sheath comprises the second semiconducting layer.

63. The method of claim 62, wherein said surrounding step, comprises surrounding the cable with the corrugations running in a longitudinal direction.

64. The method of claim 62, further comprising the step of:

extruding the outer semiconducting layer of the cable.

65. The method of claim 48, wherein:

said inserting step includes subjecting the support element to an axial tensile force to reduce a cross-sectional profile of the support element and allow passage of said support element into said space; and

releasing the tensile force when the support element is in position so as to expand the cross-sectional profile of the support element.

66. The method of claim 48, wherein:

said inserting step comprises inserting said support element in an axial direction after winding the stator.

67. The method of claim 66, wherein:

said inserting step comprises inserting the support element into a space between a cable lead-through of said cable and a wall of at least one of said first slot, said second slot, and said third slot while having said support element maintain a state that enables said support element to pass through a profile of said at least one of said first slot, said second slot, and said third slot without obstruction or resistance in an axial cross-section of said at least one of said first slot, said second slot, and said third slot; and

expanding transversely said support element in an axial direction after said inserting step.

68. The method of claim 67, wherein:

said inserting step, comprises inserting a thin walled elastic hose as said support element, when said thin walled elastic hose is decompressed during insertion and such that a thinness and elasticity of said thin walled elastic hose is sufficient so as to be deformed without noticeable resistance for allowing passage of the thin walled elastic hose through the space.

69. The method of claim 67, wherein:

said inserting step comprises inserting the support element when surrounding an elongated body along an entire length of the thin walled elastic hose such that a cross-sectional dimension of said body and said hose, having a void space formed therebetween, and filling said void space with a hardening elastic material after said support element is inserted into at least one of said first slot, said second slot, and said third slot and expanding the hose traversely to the axial direction.

70. The method of claim 69, wherein:

said filling step comprises filling the elongated body, which includes an inner, thin-walled hose with a pressure medium before said void space is filled.

71. The method of claim 70 further comprising:

removing the elongated body from the void space after the void space is filled and said pressure medium hardened, said elongated body being a rod element.

72. The method of claim 71, wherein the rod element having a profile with longitudinal ridges thereon.

73. The method of claim 67, wherein said support element having a cross-sectional profile such that sufficient clearance is provided for inserting said support member into said space.

74. The method of claim 67 wherein:

said inserting step includes inserting the support element, said support element being a hose having a cross-sectional profile, said cross-sectional profile being less than a cross-sectional profile of said space, and

filling the hose with a pressured medium when the hose is in place.

75. The method of claim 74, wherein said filling step comprises filling the hose with a cold-setting material as said pressure material.

76. The method of claim 74, wherein:

said filling step comprises filling said hose with at least one of a gas and a liquid, and

sealing the hose at respective ends thereof after said hose is filled with the pressure medium.

77. The method of claim 74, wherein:

said filling step comprises filling the hose with at least one of a gas and a liquid while maintaining communication between the pressure medium and a pressure source even while the rotating machine is in operation.

78. The method of claim 74, wherein said filling step comprises expanding the hose with a rod-shaped body as said pressure medium so as to expand said hose.

79. The method of claim 66 wherein:

said inserting step includes forcibly deforming the support element, said support element being a hose, and

releasing the hose from the deformed state after inserting the hose into the space.

80. The method of claim 79, wherein:

said forcibly deforming step includes gluing the hose so as to assume a forcibly deformed state, and

releasing an adhesive joint made by said glue when the hose is in place.

81. The method of claim 79, wherein:

said inserting step includes subjecting an interior of the hose to a negative pressure, and

releasing the negative pressure when the hose is in place.