Submarine electrical cable and submarine cable operation method

Patent metadata

Field	Value
Publication number	US-10373735-B2
Application number	US-201415508760-A
Country	US
Kind code	B2
Filing date	Sep 5, 2014
Priority date	Sep 5, 2014
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

Submarine electrical cable system (100) having a substantially circular cross-section and comprising: a first insulated core (1) and a second insulated core (2); a three-phase cable (3) comprising three stranded insulated cores (8) the three-phase cable (3) being stranded with the first core (1) and the second core (2); an armor (4) surrounding the first core (1), the second core (2) and the three-phase cable (3).

First claim

The invention claimed is:

1. A submarine electrical cable system having a substantially circular cross-section and comprising:
a first insulated core and a second insulated core each suitable for DC transmission;
a three-phase cable comprising three stranded insulated cores suitable for at least AC transmission, the three-phase cable being stranded with the first insulated core and the second insulated core; and
an armour surrounding the first insulated core, the second insulated core, and the three-phase cable,
wherein the submarine electrical cable system is free of insulated cores suitable for DC transmission other than said first and second insulated cores and free of three-phase cables suitable for at least AC transmission other than said three-phase cable comprising the three stranded insulated cores.

2. The submarine electrical cable system according to claim 1 , wherein the first and the second insulated cores are suitable for DC transmission at a voltage of 80 kV at least.

3. The submarine electrical cable system according to claim 2 , wherein the three stranded insulated cores of the three-phase cable are suitable for AC transmission at a voltage of 30 kV at least.

4. The submarine electrical cable system according to claim 1 , wherein the three-phase cable comprises a first sheath surrounding the three stranded insulated cores.

5. The submarine electrical cable system according to claim 1 , wherein the three stranded insulated cores of the three-phase cable are stranded with a unidirectional lay according to a first pitch and a first lay direction.

6. The submarine electrical cable system according to claim 5 , wherein the first insulated core, the second insulated core, and the three-phase cable are stranded with a unidirectional lay according to a second pitch and a second lay direction, wherein the second lay direction is opposite to the first lay direction.

7. The submarine electrical cable system according to claim 5 , wherein
the armour comprises a plurality of armour wires arranged in a single armour layer,
the armour wires are wound a unidirectional lay according to a third pitch and a third lay direction, and
the third lay direction is the same of the first lay direction.

8. The submarine electrical cable system according to claim 5 , wherein
the armour comprises a plurality of armour wires arranged in a single armour layer,
the armour wires are wound a unidirectional lay according to a third pitch and a third lay direction, and
the third pitch is from 0.4 to 2.5 times the first pitch.

9. The submarine electrical cable system according to claim 1 , wherein the three stranded insulated cores of the three-phase cable are stranded with an S-Z lay.

10. The submarine electrical cable system according to claim 1 , wherein the first insulated core, the second insulated core, and the three-phase cable are stranded with a unidirectional lay according to a second pitch and a second lay direction.

11. The submarine electrical cable system according to claim 1 , wherein the first insulated core, the second insulated core, and the three-phase cable are stranded with an S-Z lay.

12. The submarine electrical cable system according to claim 1 , wherein the three stranded insulated cores of the three-phase cable are stranded with a unidirectional lay according to a first pitch and a first lay direction, and the first insulated core, the second insulated core, and the three-phase cable are stranded with an S-Z lay.

13. The submarine electrical cable system according to claim 1 , wherein the armour comprises a plurality of armour wires arranged in a single armour layer.

14. The submarine electrical cable system according to claim 13 , wherein the armour wires are wound a unidirectional lay according to a third pitch and a third lay direction.

15. The submarine electrical cable system according to claim 1 , wherein the first insulated core and the second insulated core are configured to carry a direct current at a voltage of 600 kV at most and the three-phase cable is configured to carry an alternate current at a voltage of 170 kV at most.

16. The submarine electrical cable system according to claim 1 , wherein the first and second insulated cores and three-phase cable have diameters differing from one another of 2% at most.

17. A submarine cable system operation method, comprising:
providing a submarine cable system comprising:
a first insulted core and a second insulated core suitable for DC transmission;
a three-phase cable comprising three stranded insulated cores suitable for at least AC transmission, the three-phase cable being stranded with the first insulated core and the second insulated core; and
an armour surrounding the first insulated core, the second insulated core, and the three-phase cable;

transmitting DC electrical power by said first and second insulated cores; and
transmitting AC electrical power by said three-phase cable,
wherein the submarine cable system is free of insulated cores suitable for DC transmission other than said first and second insulated cores and free of three-phase cables suitable for at least AC transmission other than said three-phase cable comprising the three stranded insulated cores.

18. The method according to claim 17 , wherein said transmitting DC electrical power is simultaneous or alternative to said transmitting AC electrical power.

19. The method according to claim 17 , wherein said transmitting AC electrical power comprises supplying said AC electrical power from a shore substation to a wind farm generation system, and said transmitting DC electrical power comprises supplying said DC electrical power from the wind farm generation system to the shore substation.

20. The method according to claim 17 , wherein said transmitting AC electrical power comprises supplying AC electrical power generated by a wind farm system to a corresponding shore substation.

21. The method according to claim 17 , comprising discontinuing transmission of said AC electrical power, discontinuing transmission of said DC electrical power by said first insulated core, and transmitting said DC electrical power through said second insulated core as forward conductor and through the three-phase cable as return conductor.

Assignees

• Prysmian Spa

Inventors

• Marelli Marco
• Colla Luigi

Classifications

• H01B7/26

  Reduction of losses in sheaths or armouring · CPC title

• H01B7/14 Primary

  Submarine cables · CPC title

• H01B9/027

  composed of semi-conducting layers · CPC title

• H01B9/005

  including optical transmission elements · CPC title

• H01B7/1875

  Multi-layer sheaths · CPC title