Method and armoured cable for transporting high voltage alternate current

Patent metadata

Field	Value
Publication number	US-10839984-B2
Application number	US-201716606481-A
Country	US
Kind code	B2
Filing date	Apr 21, 2017
Priority date	Apr 21, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

Armoured cable ( 10 ) comprising: —a plurality of cores ( 12 ) stranded together according to a core stranding direction; —an armour ( 16 ) surrounding the plurality of cores ( 12 ) and comprising a layer of metal wires ( 16 a ) helically wound around the cores ( 12 ) according to an armour winding direction; wherein the at least one of core stranding direction ( 21 ) and the armour winding direction ( 22 ) is recurrently reversed along the cable length L so that the armoured cable ( 10 ) comprises unilay sections ( 102 ) along the cable length where the core stranding direction ( 21 ) and the armour winding direction ( 22 ) are the same. The invention also relates to a method for improving the performances of the armoured cable ( 10 ) and to a method for manufacturing the armoured cable ( 10 ).

First claim

The invention claimed is:

1. An armoured cable having a cable length and comprising:
a plurality of cores, each core comprising an electrical conductor surrounded by a respective insulating layer, stranded together according to a core stranding direction;
an armour surrounding the plurality of cores and comprising a layer of metal wires helically wound around the cores according to an armour winding direction;
wherein the plurality of cores are embedded in a polymeric filler and the armour surrounds the polymeric filler, and wherein at least one of the core stranding direction and the armour winding direction is recurrently reversed along the cable length L so that the armoured cable comprises unilay sections along the cable length where the core stranding direction and the armour winding direction are the same.

2. The armoured cable according to claim 1 , wherein the at least one of core stranding direction and the armour winding direction is recurrently reversed along the cable length L so that unilay sections alternate along the cable length with contralay sections.

3. The armoured cable according to claim 1 , wherein the unilay sections along the cable length L involve, as a whole, at least 40% of the cable length L.

4. The armoured cable according to claim 1 , wherein a number N of consecutive turns of at least one of the core stranding and the armour winding in a first direction is the same or varies along the cable length L.

5. The armoured cable according to claim 4 , wherein a number M of consecutive turns of at least one of the core stranding and the armour winding in a second direction, reversed with respect to the first direction, is the same or varies along the cable length L.

6. The armoured cable according to claim 5 , wherein N is equal to or different from M.

7. The armoured cable according to claim 4 , wherein N≥1.

8. The armoured cable according to claim 4 , wherein N≤10.

9. The armoured cable according to claim 5 , wherein M≥1.

10. The armoured cable according to claim 5 , wherein M≤10.

11. The armoured cable according to claim 1 , wherein the plurality of cores is stranded together according to a core stranding pitch A that, in modulus, is the same or varies along a cable length L.

12. The armoured cable according to claim 1 , wherein the metal wires are wound around the plurality of cores according to an armour winding pitch B that, in modulus, is the same or varies along a cable length L.

13. The armoured cable according to claim 2 , wherein the metal wires are wound around the plurality of cores according to an armour winding pitch B that, in the contralay sections, is greater, in modulus, than the armour winding pitch B in the unilay sections.

14. The armoured cable according to claim 1 , wherein the core stranding direction is recurrently reversed along the cable length L and the armour winding direction is unchanged.

15. The armoured cable according to claim 1 , wherein at least part of the armour metal wires are made of ferromagnetic material.

16. A method for improving the performances of an armoured cable having a cable length L and comprising a plurality of cores, each core comprising an electrical conductor surrounded by a respective insulating layer, stranded together according to a core stranding direction, each electric conductor having a cross section area X; and an armour surrounding the plurality of cores, the armour comprising a layer of metal wires helically wound around the cores according to an armour winding direction, the armoured cable having losses when an alternate current I is transported, said losses determining a maximum allowable working conductor temperature θ, the plurality of cores being embedded in a polymeric filler and the armour surrounds the polymeric filler, the method comprising the steps of:
reducing the losses by building the armoured cable such that the at least one of core stranding direction and the armour winding direction is recurrently reversed along the cable length L so that the armoured cable comprises unilay sections along the cable length L where the core stranding direction and the armour winding direction are the same;
building the armoured cable with a reduced value of the cross section area X of each electric conductor, as determined by the value of the reduced losses, and/or
rating the armoured cable at the maximum allowable working conductor temperature θ to transport said alternate current I with an increased value, as determined by the value of the reduced losses.

17. A method for manufacturing an armoured cable with a cable length L having losses when an alternate current I is transported, said losses determining a rating of the cable at maximum allowable conductor temperature θ, comprising the steps of:
stranding a plurality of cores, each core comprising an electrical conductor surrounded by a respective insulating layer, together according to a core stranding direction, each electric conductor having a cross section area X;
embedding the plurality of cores in a polymeric filler and surrounding the plurality of cores by helically winding an armour comprising a layer of metal wires around the plurality of cores and the polymeric filler according to an armour winding direction;
wherein at least one of the core stranding direction and the armour winding direction is recurrently reversed along the cable length L so that the armoured cable comprises unilay sections along the cable length where the core stranding direction and the armour winding direction are the same; and
wherein the cross section area X of each electric conductor is reduced and/or the rating of the cable at the maximum allowable working conductor temperature θ is increased, compared to a cable wherein the core stranding direction and armour winding direction are contralay along the cable length L.

Assignees

• Prysmian Spa

Inventors

• Maioli Paolo
• Bechis Massimo

Classifications

• H01B7/14

  Submarine cables · CPC title

• H01B13/0271

  Alternate stranding processes · CPC title

• H01B7/26 Primary

  Reduction of losses in sheaths or armouring · CPC title

• H01B9/006

  Constructional features relating to the conductors · CPC title

• H01B9/025

  composed of helicoidally wound wire-conductors · CPC title