High voltage mass-impregnated power cable
AssigneeAlcatel USA, Inc.
InventorJohn N. Johnsen
Life of this patent
Estimating the term…
Abstract
A high voltage mass impregnated power cable to be used on land and in shallow waters by including in the cable construction a pressure body having a number of pressure tapes applied in several layers on a bedding between the metal sheath and the tapes. The pressure tapes have good elastic properties and may consist of high quality metal or a strong synthetic material and are applied with a short lay length. The pressure body maintains under all load conditions including no-load, an internal pressure on the cable insulation above atmospheric pressure and high enough to prevent creation of voids in the insulation.
Claims19
A mass-impregnated power cable of circular cross section comprising:
- a single core conductor for transmitting high voltage direct current power;
- a plurality of mass-impregnated insulating tapes surrounding and positioned on said conductor;
- a sheath of circular cross section surrounding and positioned on said insulating tapes;
- a layer of a bedding material surrounding and positioned on said sheath;
- and
- a pressure body surrounding said bedding material layer and including a first layer of an elastic tape helically surrounding said bedding material layer and a second layer of an elastic tape helically surrounding said first layer, each of said elastic tapes having longitudinal side edges and a predetermined width and being positioned such that one side edge of the tape is spaced a predetermined distance from the side edge of the adjacent helical turn of the tape, each of said tapes having a length of lay equal to or less than 1.5 times the diameter of said sheath.
A high voltage mass-impregnated power cable of circular cross section to follow a predetermined cable route on land and/or on a sea bed for transferring power at voltages above 250 KV DC, comprising:
- an elongated single core conductor for transmitting direct current power at a voltage above 250 KV DC;
- a plurality of viscous mass-impregnated insulating tapes surrounding and positioned on said conductor;
- a fluid tight metal sheath of circular cross section surrounding and positioned on said insulating tapes;
- a flexible bedding material layer surrounding and positioned on said sheath;
- a pressure body surrounding said bedding material layer and including a first layer of an elastic tape helically surrounding said bedding material layer and a second layer of elastic tapes helically surrounding said first layer, each of said elastic tapes having longitudinal side edges and a predetermined width and being positioned such that one side edge of the elastic tape is spaced a predetermined distance of between 0.2 and 2.0 mm from the side edge of the adjacent helical turn of the elastic tape, each of said elastic tapes having a length of lay equal to or less than 1.5 times the diameter of said sheath and a width which is at least 20 mm and not nore than 100 mm, the number of elastic tapes in each of said first and second layers being no greater than two;
- and
- an external armoring surrounding said pressure body.
Dependencies are inferred from the claim text.