Rotating asynchronous converter and a generator device

• US 6,906,447 B2
• Filed: 05/27/1997
• Issued: 06/14/2005
• Est. Priority Date: 05/29/1996
• Status: Expired due to Fees

• Current Assignee: ABB AB (ABB Limited)
• Original Assignee: ABB AB (ABB Limited)
• Inventors: Leijon, Mats, Schütte, Thorsten, Fromm, Udo, Sasse, Christian
• Primary Examiner(s): MULLINS, BURTON S
• Application Number:
  US08/973,306
• Publication Number:
  US 20010055217A1
• Time in Patent Office: 2,940 Days
• Field of Search: 363/8, 363102-105, 363174-176, 363/159, 363/165, 363/164, 290/5, 290/6, 290/8, 290/52, 290/1.R, 310/179, 310/180, 310/184, 310195-196, 310198-208, 310/213, 174DIG 13- 33, 307/68, 148/269
• US Class Current: 310/196
• CPC Class Codes: H01F 2027/2833 using coaxial cable as wire
• CPC Class Codes: H01F 2027/329 Insulation with semiconducting layer, e.g. to reduce corona effect
• CPC Class Codes: H01F 2029/143 with control winding for generating magnetic bias
• 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 29/14 with variable magnetic bias amplitude modulation by means of variable impedance element H03C1/08 ; magnetic amplifiers H03F; circuits for automatic telephonic communication H04M3/00
• 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: H02H 3/025 Disconnection after limiting, e.g. when limiting is not sufficient or for facilitating disconnection
• CPC Class Codes: H02K 1/165 Shape, form or location of the slots
• CPC Class Codes: H02K 11/05 Rectifiers associated with casings, enclosures or brackets
• 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 3/40 for high voltage, e.g. affording protection against corona discharges
• CPC Class Codes: H02K 3/48 in slots
• CPC Class Codes: Y10S 174/13 High voltage cable, e.g. above 10kv, corona prevention
• CPC Class Codes: Y10S 174/14 : having a particular cable application, e.g. winding
• CPC Class Codes: Y10S 174/15 : in a power generation system, e.g. prime-mover dynamo, generator system
• CPC Class Codes: Y10S 174/17 : in an electric power conversion, regulation, or protection system
• CPC Class Codes: Y10S 174/19 : in a dynamo-electric machine
• CPC Class Codes: Y10S 174/20 : Stator
• CPC Class Codes: Y10S 174/22 : Winding per se
• CPC Class Codes: Y10S 174/24 : in an inductive device, e.g. reactor, electromagnet
• CPC Class Codes: Y10S 174/25 : Transformer
• CPC Class Codes: Y10S 174/26 : having a plural-layer insulation system
• CPC Class Codes: Y10S 174/28 : Plural semiconductive layers
• CPC Class Codes: Y10S 174/29 : having a semiconductive layer

Abstract

A rotating asynchronous converter for connection of AC network with equal or different frequencies employs a first stator connected to a first AC network with a first frequency and a second stator connected to a second AC network with a second frequency, and a rotor which rotates in response to the first and second frequencies. The converter has at least one winding formed of a cable, including a conductor and a magnetically permeable, electric field confining insulating covering surrounding the conductor.

Claims

1. A rotating asynchronous high voltage converter for connection of AC networks with equal or different frequencies, wherein the converter comprises a first stator connected to a first AC network with a first frequency f₁, and a second stator connected to a second AC network with a second frequency f₂, wherein the converter comprises a rotor which rotates in dependence of the first and second frequencies f₁, f₂, and wherein at least one of said stators includes at least one winding forming at least one uninterrupted turn, said winding including a current-carrying conductor a plurality of insulated conductive elements and at least one uninsulated conductive element, and a magnetically permeable, electric field confining insulating covering surrounding the conductor, including an inner layer having semiconducting properties being in electrical contact with the conductor, an insulating layer surrounding the inner layer being in intimate contact therewith and an outer layer having semiconducting properties surrounding the insulating layer and being in intimate contact therewith, wherein each layer forms a substantially equipotential surface.

2. The rotating asynchronous converter according to claim 1, wherein at least one of said semiconducting layers has substantially equal thermal expansion coefficient as said solid insulation.

3. The rotating asynchronous converter according to claim 2, wherein the potential of the inner one of said layers is substantially equal to the potential of the conductor.

4. The rotating asynchronous converter according to claim 1, wherein the outer layer is arranged to form substantially an equipotential surface surrounding said conductor.

5. The rotating asynchronous converter according to claim 4, wherein said outer layer is connected to a specific potential.

6. The rotating asynchronous converter according to claim 5, wherein said specific potential is ground potential.

7. The rotating asynchronous converter according to claim 1, wherein said inner and outer layers have substantially equal thermal expansion coefficients.

8. The rotating asynchronous converter according to claim 1, wherein each of said inner and outer layers is fixedly connected to the adjacent layer of solid insulation along substantially the whole of a connecting surface therebetween.

9. The rotating asynchronous converter according to claim 1, wherein the winding comprises a cable having a diameter comprised in the approximate interval 20-250 mm and a conductor area comprised in the approximate interval 80-3000 mm².

10. The rotating asynchronous converter according to claim 1, wherein said rotor comprises two electrically and mechanically connected rotors, which are concentrically arranged in respect of said stators.

11. The rotating asynchronous converter according to claim 10, wherein said converter further comprises an auxiliary device connected to said rotors for starting up the rotors to a suitable rotation speed before connection of said converter.

12. The rotating asynchronous converter according to claim 11, wherein each of said rotors comprises a low voltage winding, and wherein said rotors are rotatable with the frequency (f₁−

f₂)/2 and the stator has a current with a frequency (f₁+f₂)/2 when said converter is in operation.

13. The rotating asynchronous converter according to claim 1 wherein said rotor comprises a single rotor concentrically arranged in respect of said stators.

14. The rotating asynchronous converter according to claim 13, wherein said rotor comprises a first loop of cable and a second loop of cable, wherein said loops of cable are connected to each other and are arranged opposite each other on said rotor and separated by two sectors, wherein each sector has an angular width of α

.

15. The rotating asynchronous converter according to claim 14, wherein said converter further comprises an auxiliary device connected to said rotor for starting up the rotor to a suitable rotational speed before connection of said converter, and said rotor is rotatable with the frequency $f_R=\frac{\pi }{}$

-α

π

⁢

 

·

 

⁢

Δ

⁢

 

⁢

f4,

wherein Δ

f=|f₁−

f₂|.

16. The use of a rotating asynchronous converter in accordance with claim 1 for connection of non-synchronous three phase networks with equal rating frequencies.

17. The use of a rotating asynchronous converter in accordance with claim 1 for connection of three phase networks with different frequencies.

18. The use of a rotating asynchronous converter in accordance with claim 1 as a series compensation in long distance AC transmission.

19. The use of a rotating asynchronous converter in accordance with claim 1 for reactive power compensation.

20. A rotating asynchronous converter for connection of AC networks with equal or different frequencies, wherein the converter comprises a first stator for connection to a first AC network with a first frequency f₁, and a second stator for connection to a second AC network with a second frequency f₂, rotor means rotatable in dependence of the first and second frequencies f₁, f₂, and each stator includes at least one winding forming at least one uninterrupted turn, said winding comprising at least one current-carrying conductor a plurality of insulated conductive elements and at least one uninsulated conductive element, and a magnetically permeable, electric field confining insulation system surrounding the conductor, including an inner layer having semiconducting properties being in electrical contact with the conductor, an insulating layer surrounding the inner layer being in intimate contact therewith, and an outer layer having semiconducting properties surrounding the insulating layer and being in intimate contact therewith, wherein each layer forms a substantially equipotential surface, which permits a voltage level in said rotating asynchronous converter exceeding 36 kV.

21. A generator device operable with variable rotational speed, wherein the generator device comprises a stator for connection to an AC network with a frequency f₂, a first cylindrical rotor for connection to a turbine, rotatable at a frequency f₁, wherein said generator device comprises rotor means being rotatable in dependence of the frequencies f₁, f₂, and said stator and said first cylindrical rotor each includes at least one winding forming at least one uninterrupted turn, said winding comprising at least one current-carrying conductor a plurality of insulated conductive elements and at least one uninsulated conductive element, and a magnetically permeable, electric field confining insulation system, including an inner layer having semiconducting properties being in electrical contact with the conductor, an insulating layer surrounding the inner layer being in intimate contact therewith and an outer layer having semiconducting properties surrounding the insulating layer and being in intimate contact therewith, wherein each layer forms a substantially equipotential surface surrounding the conductor.

22. The generator device according to claim 21, wherein at least one of said semiconducting layers has substantially equal thermal expansion coefficient as said solid insulation.

23. The generator device according to claim 22, wherein the inner layer has a potential substantially equal to a potential of the conductor.

24. The generator device according to claim 22, wherein the outer one of said layers is arranged to form substantially an equipotential surface surrounding said conductor.

25. The generator device according to claim 24, wherein said outer layer is connected to a specific potential.

26. The generator device according to claim 25, wherein said specific potential is ground potential.

27. The generator device according to claim 21, wherein at least two of said layers have substantially equal thermal expansion coefficients.

28. The generator device according to claim 21, wherein each of said two layers and said solid insulation is connected to adjacent layer or solid insulation along substantially the whole connecting surface.

29. A generator device with variable rotational speed comprising a stator for connection to an AC network with a frequency f2, a first cylindrical rotor for connection to a turbine, being rotatable with a frequency f₁, wherein said generator device comprises rotor means including two electrically and mechanically connected hollow rotors arranged concentrically around said stator and said cylindrical rotor, being rotatable in dependence of the frequencies f₁, f₂, and said stator and said first cylindrical rotor each comprises at least one winding, forming at least one uninterrupted turn, wherein each winding comprises a cable including at least one current-carrying conductor,

each conductor comprises a number of conductive elements,

an inner semiconducting layer surrounding the conductor and being in electrical contact therewith,

an insulating layer of solid insulation surrounding the inner layer and being in intimate contact therewith, and

an outermost layer having semiconducting properties surrounding the insulating layer and being in intimate contact therewith, wherein each inner and outermost layer forms a substantially equipotential surface surrounding the conductor.

30. The generator device according to claim 29, wherein the cable has a diameter of about 20-250 mm and a conductor area is about 80-3000 mm².

31. The generator device according to claim 29, wherein said rotor means comprises a plurality of insulated conductive elements and at least one uninsulated conductive element.

32. The generator device according to claim 29, wherein each of said rotors comprises a low voltage winding, and said rotor is rotatable at a frequency (f₁−

f₂)/2 when said generator device is in operation.

33. The generator device according to claim 32, wherein said stator has a cylindrical shape.

34. The generator device according to claim 29, wherein said two rotors comprise a first rotor and a second rotor, wherein-said first rotor is arranged concentrically around said first cylindrical rotor, and said second rotor is cylindrical.

35. The generator device according to claim 29, wherein said first and second rotors of said rotor means each comprises a low voltage winding, and wherein said first and second rotors are rotatable at a frequency (f₁−

f₂)/2 when said generator device is in operation.

36. The generator device according to claim 35, wherein said stator is hollow and arranged around said second rotor.

37. A rotating asynchronous converter employing a high voltage electric machine comprising a stator, a rotor and a winding comprising a cable including at least one current-carrying conductor and a magnetically permeable, electric field confining cover surrounding the conductor and being in electrical contact therewith, said conductor including a plurality of insulated conductive strands and at least one uninsulated conductive strand in contact with the cover, said cable forming at least one uninterrupted turn in the corresponding winding of said machine, and wherein said cover includes

an inner semiconducting layer surrounding the conductor;

and being in electrical contact therewith,

an outermost layer of solid insulation surrounding the inner layer and being in intimate contact therewith, and

an outermost layer having semiconducting properties surrounding the insulating layer and being in intimate contact therewith, wherein each inner and outermost layer forms a substantially equipotential surface surrounding the conductor.

38. The converter of claim 37, wherein the inner layer and outermost layer each have a conductivity sufficient to establish an equipotential surface around the conductor.

39. The converter of claim 37, wherein the inner layer and outermost layer have semiconducting properties.

40. The converter of claim 37, wherein the inner layer, insulating layer and outermost layer are substantially void free.

41. The converter of claim 37, wherein the machine is operable at 100% overload for two hours.

42. The converter of claim 37, wherein the winding is operable free of sensible end winding loss.

43. The converter of claim 37, wherein the winding is operable free of partial discharge and field control.

44. The converter of claim 37, wherein the winding comprises multiple uninterrupted turns.

45. The converter of claim 37, wherein the cable is flexible.

46. A rotating asynchronous converter for connection of AC networks with equal or different frequencies, wherein the converter comprises a first stator connected to a first AC network with a first frequency f₁, and a second stator connected to a second AC network with a second frequency f₂, wherein the converter further comprises rotor means which rotates in dependence of said first and second frequencies f₁, f₂, said stators each comprise at least one winding, wherein each winding comprise a cable including at least one current-carrying conductor, and an electric field confining, solid insulation covering surrounding the conductor, said conductor including at least one of a plurality of insulated conductive elements and at least one uninsulated conductive element in contact with the covering, said cable comprising

an inner semiconducting layer surrounding the conductor, and being in electrical contact therewith

an insulating layer of solid insulation surrounding the inner layer and being in intimate contact therewith, and

an outermost layer having semiconducting properties surrounding the insulating layer and being in intimate contact therewith, wherein each inner and outermost layer forms a substantially equipotential surface surrounding the conductor.