Submarine power cable conductor

DETAILED DESCRIPTION I claim: 1.
A submarine power cable conductor comprising: at least one central conductor consisting of at least one layer of metal wires stranded helically at mean stranding pitch (P), insulation surrounding said stranded metal wires, and helically wound armour wires surrounding said insulation, the improvement wherein all central conductor metal wires are laid in the same direction and at a periodically varied angle a wherein the periodically varied angle generates undulation of all the central conductor wires such that all of the central conductor wires twist about a mean winding helix; and wherein the varied angle pitch (p) of the undulation is less than twice the mean standing pitch (P); whereby, when the central conductor is stretched, each wire in the central conductor will follow the elongation thereof through a modification of its geometrical position, bringing it closer to said means winding helix without any elongation of the wire itself, with the central conductor being of a greater length than the armour so that the armour will fulfill its carrier function and all wires of the central conductor are longer than the armour.
2.
A conductor as in claim 1, wherein the peak-to-peak amplitude (.
epsilon.
) of the undulation is less than 0.
1 times the pitch (p) of the undulation.




Description:
This invention concerns a conductor for submarine or undersea power cable, as well as a method of manufacturing such a conductor.
A submarine power cable basically consists of one to three conductors stranded at a constant pitch and insulated, said assembly being surrounded by an armor of helically wound steel wires.
The purpose of the armor is to protect the insulation layers and to increase the cable's tensile strength.
During laying of the cable, the cable is subjected to a tensile force F induced by its own weight.
As a result, the cable becomes elongated, generally by less than 1%, and a force F.
sub.
1 is induced in the conductor and a force F.
sub.
2 in the armoring, where F=F