Electric power transport system comprising a cold dielectric superconducting cable

1. An electric power transport system comprising:

at least a cold dielectric superconducting cable including two concentric phases of superconducting material electrically isolated one from the other by a dielectric and a first cryogenic fluid flowing channel inside the cable;

a cryostat circumscribing a cryogenic fluid flowing channel, said channel containing said cable; and

a cryogenic fluid,

said cryostat comprising at least two modules, each comprising

an inner tube, having at least a coupling flange for said at least two modules extending in a radially external direction; and

an outer tube having a length not greater than the length of said inner tube;

wherein at least one of said modules comprises

at least a radially inner gasket and at least a radially outer gasket on the coupling surface of said at least one flange, the radially external perimeter of the inner gasket being spaced from the radially internal perimeter of the outer gasket; and

at least a duct having a first end connected to said coupling surface of said at least one flange comprised between said gaskets and a second end connected to the environment external to the cryostat.

2. The electric power transport system according to claim 1 , wherein said inner tube and outer tube are associated by spacers substantially adjacent to the extremities of at least said outer tube.

3. The electric power transport system according to claim 2 , wherein said spacers and said inner and outer tubes define an under vacuum gap.

4. The electric power transport system according to claim 1 , wherein said gaskets are housed in a slot present on the coupling surface of said at least one flange.

5. The electric power transport system according to claim 1 , wherein said gaskets are each housed in a corresponding slot, respectively radially inner and outer slots, the inner slot having a radially outer diameter smaller than a radially inner diameter of the outer slot.

6. The electric power transport system according to claim 5 , wherein said at least one slot has an axial right section selected between triangular and rhomboidal.

7. The electric power transport system according to claim 1 , wherein both modules have said at least one slot in said at least one flange.

8. The electric power transport system according to claim 1 , wherein said outer tube is flanged in radially external direction.

9. The electric power transport system according to claim 1 , wherein said outer tube is provided with an axially external moving sleeve.

10. The electric power transport system according to claim 3 , wherein said under vacuum gap contains thermal insulating material.

11. The electric power transport system according to claim 1 , wherein said duct is metallic.

12. The electric power transport system according to claim 11 , wherein said duct is in corrugated stainless steel.

13. The electric power transport system according to claim 1 , wherein said duct has a diameter smaller than 10 mm.

14. The electric power transport system according to claim 13 , wherein the diameter is smaller than 4 mm.

15. The electric power transport system according to claim 1 , wherein said duct is coated with thermal insulating material.

16. The electric power transport system according to claim 1 , wherein said duct is wound around said inner tube.

17. The electric power transport system according to claim 1 , wherein at least one of said gaskets is in two halves.

18. The electric power transport system according to claim 1 , wherein said duct is filled with an overpressure fluid.

19. A cryostat for a cold dielectric superconducting cable comprising at least two modules reciprocally coupled, each module comprising:

an inner tube having at least a coupling flange for said at least two modules, extending in a radially external direction; and

an outer tube having a length not greater than the length of said inner tube;

wherein at least one of said modules comprises

at least a radially inner gasket and at least a radially outer gasket on the coupling surface of said at least one flange, the radially external perimeter of the inner gasket being spaced from the radially internal perimeter of the outer gasket, and

at least a duct having a first end connected to said coupling surface of said at least one flange, comprised between said gaskets and a second end connected to the environment external to the cryostat.

20. The cryostat according to claim 19 , wherein said at least two modules are coupled so as to create an intermediate space radially external to said inner tube of said two modules.

21. The cryostat according to claim 20 , wherein said intermediate space is under vacuum.

22. The cryostat according to claim 20 , wherein said intermediate space contains thermal insulating material.