Patent ID: 6972374

Claim:
A flexible superconducting core for a superconducting power cable, said core comprising: a) a helical central corrugated flexible tubular element made of stainless steel; b) a stainless steel core mesh positioned around said helical central corrugated flexible tubular element to provide a relatively flat surface, said mesh consisting of: i) a first layer of steel tape of one size; and ii) a second layer of steel tape having a different size from said first said one size of said first layer of steel tape, said second layer being positioned over said first layer; c) a layer of at least one copper tape positioned on top of said second layer of said core mesh; d) a plurality of superconducting tapes layered over said at least one copper tape, forming a first group of a plurality of superconducting tape layers; e) a second group of a plurality of superconducting tape layers, at least one layer of said second group positioned on top of said first group of plurality of superconducting tape layers and being wound in one direction opposite to that of (d); and wherein a pitch of the layers varies from a maximum P max1 and P max2 in intermediate layers to minimum P min1 and P min2 in inner and outer layers, while twist angles of the tapes in the layers vary from α max1 to α min1 and from α max2 to α min2 and at least one layer of tapes from normally conducting metal is located between the outer surface of the former and the inner surface of said layer, wherein: a) for the inner layers: i) P min1 and α max1 are defined as minimum pitch and maximum twist angle of said tapes in the first layer made of superconducting tapes from the cable axis: ii) P maz1 and α min1 are defined as maximum pitch and minimum twist angle of said tapes in the last layers made of superconducting tapes of the first group of layers adjacent to the central core and having one direction of lay; and b) for the outer layers: i) P min2 and α max2 are defined as minimum pitch and maximum twist angle of tapes in the first layer made of superconducting tapes from the cable axis; and ii) P max2 and α min2 are defined as maximum pitch and minimum twist angle of tapes in the last layers made of superconducting tapes of the second group of layers with opposite direction of lay.