Claims
- 1. An electric power cable, comprising:
- a conductor;
- insulation surrounding said conductor, said insulation having at least portions thereof formed by winding on said conductor polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
- 2. The electric power cable according to claim 1, wherein said insulation further comprises kraft paper, said kraft paper being wound around said conductor alternately with said polypropylene film.
- 3. The electric power cable according to claim 2, wherein an alternate winding of polypropylene film and kraft paper comprises at least a combination of one sheet of polypropylene film and one sheet of kraft paper.
- 4. The electric power cable according to claim 2 wherein an alternate winding of polypropylene film and kraft paper comprises at least a combination of two sheets of polypropylene sheet and one sheet of kraft paper.
- 5. The electic power cable according to claim 2, wherein a portion of said surfaces of said polypropylene film and kraft paper have a roughness in a range of 1 to 50 microns.
- 6. The electric power cable according to claim 2, wherein said kraft paper comprises raw kraft paper.
- 7. The electric power cable according to claim 2, wherein said kraft paper comprises moisture-conditioned raw kraft paper.
- 8. The electric power cable according to claim 2, wherein said insulating oil comprises dodecyl benzene.
- 9. The electric power cable according to claim 2, wherein said cable is conditioned by heating for 24 to 48 hours at a highest expected operating temperature prior to shipment.
- 10. The electric power cable according to claim 1, wherein said insulation comprises a plurlity of layers, said layers comprising a combination of kraft paper and polypropylene film.
- 11. The electric power cable according to claim 10, wherein one of said layers comprises 3 to 10 plies of said kraft paper.
- 12. The electric power cable according to claim 10, wherein there are more than five layers and, in the innermost five layers, alternate ones of said layers are wound in opposite directions, and wherein, at gaps formed at intersections between adjacent ones of said layers, plies laterally adjacent to said gap are formed of said kraft paper.
- 13. The electric power cable according to claim 1, wherein said insulation comprises an electrically insulating paper laminate comprising two sheets of electrically insulating paper bonded together with a single polypropylene adhesive layer melt extruded between said sheets, said laminate being wound on said conductor alternately with said polypropylene film.
- 14. The electric power cable according to claim 13, wherein at least one alternate winding of polypropylene film and said laminate is a combination of one sheet of polypropylene film and one sheet of said laminate.
- 15. The electric power cable according to claim 13, wherein at least one alternate winding of polypropylene film and said laminate is a combination of two sheets of polypropylene sheet and one sheet of said laminate.
- 16. The electric power cable according to claim 13, wherein a portion of either or both surfaces of at least a portion of said polypropylene film and said laminate have a roughness in a range of 1 to 50 microns.
- 17. The electric power cable according to claim 13, wherein said laminate comprises raw laminate.
- 18. The electric power cable according to claim 13, wherein said laminate comprises moisture-conditioned raw laminate.
- 19. The electric power cable according to claim 13, wherein said insulating oil comprises dodecyl benzene.
- 20. The electric power cable according to claim 13, wherein said cable is conditioned by heating for 24 to 48 hours at a highest expected operating temperature prior to shipment.
- 21. The electric power cable according to claim 13, wherein said insulation comprises a plurality of layers, each of said layers comprising a plurality of plies of tapes.
- 22. The electric power cable according to claim 14, wherein said insulation further comprising kraft paper.
- 23. The electric power cable according to claim 22, wherein a layer of said insulation comprises 3 to 10 plies of said kraft paper.
- 24. The electric power cable according to claim 10, wherein there are more than five layers and, in the innermost five layers, alternative ones of said layers are wound in opposite directions, and wherein, at gaps formed at intersections between adjacent ones of said layers, plies laterally adjacent to said gap are formed of said kraft paper.
- 25. An electric power cable, comprising:
- a conductor;
- insulation formed around said conductor, said insulation comprising an inner insulating layer, an intermediate insulating layer, and an outer insulating layer, said insulating layers having different dielectric constants such that a dielectric constant of said insulating layers is sequentially graded with the largest value constant at said inner layer and the smallest value constant at said outer layer, at least said outer insulating layer including polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
- 26. The electric power cable according to claim 25, wherein said insulation further comprising kraft paper.
- 27. The electric power cable according to claim 26, wherein a layer of said insulation comprises 3 to 10 plies of said kraft paper.
- 28. The electric power cable according to claim 27, wherein there are more than five layers and, in the innermost five layers of said insulation, alternate ones of said layers are wound in opposite directions, and wherein, at gaps formed at intersections between adjacent ones of said layers, plies laterally adjacent to said gap are formed of said kraft paper.
- 29. The electric power cable according to claim 27, wherein said kraft paper comprises raw kraft paper.
- 30. The electric power cable according to claim 27, wherein said kraft paper comprises moisture-conditioned raw kraft paper.
- 31. The electric power cable according to claim 25, wherein said insulation oil comprises dodecyl benzene.
- 32. The electric power cable according to claim 25, wherein said cable is conditioned by heating for 24 to 48 hours at a highest expected operating temperature prior to shipment.
- 33. The electric power cable according to claim 25, wherein said inner insulating layer is formed of kraft paper and said outer insulating layer is formed of an alternating combination of two sheets of polypropylene film and an electrically insulating paper laminate comprising two sheets of electrically insulating paper bonded together with a single polypropylene adhesive layer melt extruded between said sheets, said laminate being wound on said conductor alternately with said polypropylene film.
- 34. The electric power cable according to claim 33, wherein said intermediate insulating layer comprises an alternating combination of a sheet of kraft paper and a sheet of said polypropylene film.
- 35. The electric power cable according to claim 33, wherein said intermediate insulating layer comprises an alternating combination of a sheet of kraft paper and two sheets of polypropylene film.
- 36. The electric power cable according to claim 33, wherein said intermediate insulating layer comprises an alternating combination of a sheet of polypropylene film and said laminate.
- 37. The electric power cable according to claim 33, wherein said intermediate insulating layer comprises first, second and third insulating layers, said first insulating layer comprising an alternating combination of a sheet of kraft paper and a sheet of polypropylene film, said second insulating layer comprising an alternating combination of a sheet of kraft paper and two sheets of polypropylene film, and said third insulating layer comprising an alternating combination of a sheet of polypropylene film and a laminate of a sheet of polypropylene and two sheets of kraft paper sandwiching said polypropylene film sheet.
- 38. The electric power cable according to claim 32, wherein at least a portion of at least one surface of at least one of said kraft paper, said polypropylene film, and said laminate has a surface roughness in a range of 1 to 50 microns.
- 39. An electric power cable, comprising:
- a conductor;
- insulation formed around said conductor, said insulation comprising, in order from said conductor, at least a layer comprising one laminate and one sheet of polypropylene film followed by a layer comprising one laminate and two sheets of polypropylene film, said polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
- 40. An electric power cable, comprising:
- a conductor;
- insulation formed around said conductor, said insulation comprising, in order from said conductor, a layer comprising one sheet of kraft paper and two sheets of polypropylene film and a layer comprising one laminate and one sheet of polypropylene film, said polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
- 41. An electric power cable, comprising:
- a conductor;
- insulation formed around said conductor, said insulation comprising, in order from said conductor, a layer comprising one sheet of kraft paper and one sheet of polypropylene film and a layer comprising one sheet of kraft paper and two sheets of polypropylene film, said polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
- 42. An electric power cable, comprising:
- a conductor;
- insulation formed around said conductor, said insulation comprising, in order from said conductor, a layer comprising one sheet of kraft paper and two sheets of polypropylene film, a layer comprising one laminate and one sheet of polypropylene film, and a layer comprising one laminate and two sheets of polypropylene film, said polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
- 43. An electric power cable, comprising:
- a conductor;
- insulation formed around said conductor, said insulation comprising, in order from said conductor, a layer comprising one sheet of kraft paper and one sheet of polypropylene film, a layer comprising one sheet of kraft paper and two sheets of polypropylene film, and a layer comprising one laminate and one sheet of polypropylene film, said polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
- 44. An electric power cable, comprising:
- a conductor;
- insulation formed on said conductor, said insulation comprising, in order from said conductor, a layer comprising one sheet of kraft paper, a layer comprising one sheet of kraft paper and one sheet of polypropylene film, and a layer comprising one sheet of kraft paper and two sheets of polypropylene film, said polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
- 45. An electric power cable, comprising:
- a conductor;
- insulation formed on said conductor, said insulation comprising, in order from said conductor, a layer comprising one sheet of kraft paper and one sheet of polypropylene film, a layer comprising one sheet of kraft paper and two sheets of polypropylene film, a layer comprising one laminate and one sheet of polypropylene film, and a layer comprising one laminate and two sheets of polypropylene film, said polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
- 46. An electric power cable, comprising:
- a conductor;
- insulation formed around said conductor, said insulation comprising, in order from said conductor, a layer comprising one sheet of kraft paper, a layer comprising one sheet of kraft paper and one sheet of polypropylene film, a layer comprising one sheet of kraft paper and two sheets of polypropylene film, and a layer comprising one laminate and one sheet of polypropylene film, said polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
- 47. An electric power cable, comprising:
- a conductor;
- insulation formed on said conductor, said insulation comprising, in order from said conductor, a layer comprising one sheet of kraft paper, a layer comprising one sheet of kraft paper and one sheet of polypropylene film, and a layer comprising one laminate and one sheet of polypropylene film, said polypropylene film having a density in a range of 0.905 to 0.915 g/cm.sup.3, a birefringence in a range of 0.020 to 0.035, a ratio of a lengthwise tensile strength to a widthwise tensile strength in a range of 5 to 15, and a thickness in a range of 70 to 300 microns; and
- insulating oil with which said insulation is impregnated.
Priority Claims (1)
Number |
Date |
Country |
Kind |
59-132451 |
Jun 1984 |
JPX |
|
Parent Case Info
This is a continuation-in-part of application Ser. No. 743,884 filed June 12, 1985, now abandoned, which is a continuation of application Ser. No. 619,423 filed June 11, 1984, now abandoned.
US Referenced Citations (7)
Foreign Referenced Citations (3)
Number |
Date |
Country |
95292 |
Aug 1978 |
JPX |
109406 |
Aug 1981 |
JPX |
1045527 |
Oct 1966 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Cheng, F. S. et al.; Effect of Impregnant on the Electrical and Mechanical Properties of Polypropylene Paper; Wire and Wire Products; May 1972; pp. 57-63. |
Continuations (1)
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Number |
Date |
Country |
Parent |
619423 |
Jun 1984 |
|
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
743884 |
Jun 1985 |
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