Conductor for high-voltage windings and a rotating electric machine comprising a winding including the conductor

• US 6,376,775 B1
• Filed: 02/09/1999
• Issued: 04/23/2002
• Est. Priority Date: 05/29/1996
• Status: Expired due to Fees

• Current Assignee: ABB AB (ABB Limited)
• Original Assignee: ABB AB (ABB Limited)
• Inventors: Johannesson, Kenneth, Milton, Stefan, Leijon, Mats, Rydholm, Bengt, Carstensen, Peter
• Primary Examiner(s): Nguyen, Chau N.
• Application Number:
  US09/147,319
• Time in Patent Office: 1,169 Days
• Field of Search: 174/113.R, 174/105.R, 174/106.R, 174/105.SC, 174/106.SC, 174/120.SC, 174/126.1, 174/126.2, 174/128.1, 174/128.2, 174/110.A, 174/DIG-14-, 174/127
• US Class Current: 174/128.1
• CPC Class Codes: H01F 2027/329 Insulation with semiconducting layer, e.g. to reduce corona effect
• CPC Class Codes: H01F 27/288 Shielding
• CPC Class Codes: H01F 27/323 Insulation between winding turns, between winding layers
• CPC Class Codes: H01F 27/34 Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
• CPC Class Codes: H01F 3/10 Composite arrangements of magnetic circuits
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12
• CPC Class Codes: H02K 1/165 Shape, form or location of the slots
• 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 15/12 Impregnating, heating or drying of windings, stators, rotors or machines
• CPC Class Codes: H02K 2203/15 Machines characterised by cable windings, e.g. high-voltage cables, ribbon cables
• CPC Class Codes: H02K 3/14 with transposed conductors, e.g. twisted conductors
• 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 3/34 between conductors or between conductor and core, e.g. slot insulation
• CPC Class Codes: H02K 3/40 for high voltage, e.g. affording protection against corona discharges
• CPC Class Codes: H02K 3/48 in slots

Abstract

A conductor and a rotating electric high-voltage machine that includes the conductor has a cable configured for high-voltage operation. The cable may be included as a winding for the rotating electric high-voltage machine. The conductor includes a first strand that is clad with an electrically insulating layer, and a second strand that is uninsulated whereas the first strand and the second strand are arranged in two or more layers of strands. The two or more layers of strands are insulated from one another. Furthermore, the first and second layers of the two or more layers of strands are arranged around a central core where the central core is at least one of an air core and a core of another material. The second strand is positioned so as not to be electrically contacting any other uninsulated strand.

Claims

1. A conductor for carrying a current in a high-voltage winding in an electric machine, comprising:

a first strand being clad with an electrically insulating layer; and

a second strand being uninsulated, wherein

said first strand and said second strand being arranged in two or more layers of strands,

said two or more layers of strands being insulated from one another,

said two or more layers being arranged around a central core, said central core being at least one of

another strand that is one of an insulated strand and an uninsulated strand, and

at least one of an air core and another material, and

said second strand being positioned so as to not electrically contact any uninsulated strands.

2. The conductor of claim 1, wherein:

at least one strand in an outermost layer of said two or more layers of strands being uninsulated.

3. The conductor of claim 2, wherein:

at least one strand in an outermost layer of said two or more layers of strands being uninsulated; and

said two or more layers of strands having circular strands arranged concentrically with alternating stranding direction in respective of the two or more layers of strands.

4. The conductor of claim 3, wherein:

respective of the first strand and second strand having a pre-shaped cross-section.

5. The conductor of claim 2, wherein:

said two or more layers of strands having at least three strand layers, said at least three strand layers having alternate layers, wherein

every other strand in each of said alternate layers being uninsulated; and

said at least three layers being formed with circular strands and being arranged concentrically with alternating stranding direction.

6. The conductor of claim 2, wherein:

said two or more layers of strands being formed with circular strands arranged concentrically with alternating stranding direction; and

every other strand in each of said alternate layers being uninsulated; and

respective of the two or more layers of strands, being insulated from one another by an insulating tape.

7. The conductor of claim 6, wherein:

the insulating tape being arranged either longitudinally along the respective two or more layers of strands or spun between the two or more layers of strands.

8. The conductor of claim 6, wherein:

the insulating tape being at least one of paper and a synthetic material.

9. The conductor of claim 1, wherein:

said two or more layers of strands being arranged in a common layer direction.

10. The conductor of claim 1, wherein:

a diameter of at least one of the first strand and the second strand not exceeding 4 mm.

11. The conductor of claim 10, wherein:

said diameter being approximately 2 mm.

12. The conductor of claim 1, wherein:

said first strand being an aluminum wire having an insulating oxide layer thereon; and

said second strand being at least one of an uninsulated copper wire and a uninsulated aluminum wire.

13. The conductor of claim 1, wherein:

a minority of said strands in the two or more layers of strands being uninsulated from each other.

14. A rotating electric high-voltage machine comprising:

a stator;

a rotor opposing said stator; and

a high-voltage winding in said stator and having a cable, said cable having

a conductor for carrying a current,

a first semiconducting layer formed around said conductor,

a solid insulating layer formed around said first semiconducting layer, and

a second semiconducting layer formed around said solid insulating layer, wherein

said conductor includes

a first strand clad with an electrically insulating layer, and

a second strand being uninsulated.

15. The machine of claim 14, wherein:

a potential of said conductor being substantially equal to that of said first semiconducting layer.

16. The machine of claim 14, wherein:

said second semiconducting layer being configured to provide a substantially equipotential surface surrounding said conductor.

17. The machine of claim 16, wherein:

said second semiconducting layer being connected to a predetermined potential.

18. The machine of claim 17, wherein:

said predetermined potential being a ground potential.

19. The machine of claim 14, wherein:

said solid insulating having a thermal expansion coefficient being substantially equal to that of at least one of the first semiconducting layer and the second semiconducting layer.

20. The machine of claim 14, wherein:

said solid insulating layer being solidly connected along a whole connecting surface to said first semiconducting layer and another connecting surface to said second semiconducting layer.

21. A rotating electric high-voltage machine having a magnetic circuit, comprising:

a magnetic core; and

a high-voltage winding having a cable with

a multi-strand conductor configured to carry an electric current,

a first semiconducting layer formed around said multi-strand conductor,

a solid insulating layer formed around said first semiconducting layer, and

a second semiconducting layer formed around said solid insulating layer, wherein

said multi-strand conductor includes

a first strand being clad with an electrically insulating layer, and

a second strand being uninsulated,

said first strand and said second strand being arranged in two or more layers of strands that are insulated from one another,

said two or more layers being arranged around a central core, said central core being at least one of

another strand that is either an insulated strand or an uninsulated strand, and

at least one of an air core and another material, and

said second strand being positioned so as to not electrically contact any uninsulated strands.