Extra-high-voltage power cable
First Claim
Patent Images
1. An extra-high-voltage electric power cable comprising:
- a conductor;
a first at least semi-conductive screen around and contacting said conductor;
an inner first insulating layer of an unfilled high density polyethylene or polypropylene material having a predetermined electric strength around said semi-conductive screen;
at least a second insulating layer around said first insulating layer, sad second insulating layer having an electric strength less than said predetermined electric strength of said first insulating layer; and
,a second at least semi-conductive screen around said second insulating layer.
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Abstract
An extra-high-voltage power cable is provided with extruded insulation 3 over a conductor 1 thereof. The insulation comprises an inner layer 5 of an unfilled high density polyethylene or polypropylene material having a higher electric strength than the material of the insulation adjacent thereto in an outer layer 6 thereof.
49 Citations
12 Claims
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1. An extra-high-voltage electric power cable comprising:
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a conductor; a first at least semi-conductive screen around and contacting said conductor; an inner first insulating layer of an unfilled high density polyethylene or polypropylene material having a predetermined electric strength around said semi-conductive screen; at least a second insulating layer around said first insulating layer, sad second insulating layer having an electric strength less than said predetermined electric strength of said first insulating layer; and
,a second at least semi-conductive screen around said second insulating layer. - View Dependent Claims (2, 3, 4, 5, 7, 8)
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9. A method of manufacturing an extra-high voltage cable having a conductor, said method comprising:
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extruding a first layer of semi-conductive plastic material over said conductor; extruding an insulating second layer of unfilled high density polyethylene or polypropylene material having a predetermined electric strength over said first layer; extruding a third layer of an insulating material over said second layer, the last-mentioned said material having an electric strength less than said predetermined electric strength of said material of said second layer; and
,extruding a further layer of semi-conductive plastic material over said third layer. - View Dependent Claims (10)
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11. A method of manufacturing an extra-high-voltage cable having a conductor, said method comprising:
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extruding a first layer of a semi-conductive plastic material over said conductor; extruding an insulating second layer of unfilled high density polyethylene or polypropylene material having a predetermined electric strength over an din contact with said first layer; optically inspecting the interface between said first layer and said second layer through said second layer; and
,after optically inspecting said interface, extruding a third layer of an insulating material over said second layer, the last-mentioned said material having an electric strength less than said predetermined electric strength of said material of said second layer. - View Dependent Claims (6, 12)
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Specification