FR2729501A1 - HIGH VOLTAGE CURRENT BETWEEN A BTC SUPERCONDUCTING INSTALLATION AND AN AMBIENT TEMPERATURE CONNECTION END OF A HIGH VOLTAGE CABLE - Google Patents

Abstract

The invention relates to a high voltage current supply between a superconducting application (2) at low critical temperature (4, 2K) and a connection end (3) at room temperature (300K) of a high voltage power cable, said feed comprising at least one superconducting element (4) at high critical temperature (77K), electrically conducting means (5) between a first end (6) of the superconducting element (4) at high critical temperature and the end connection (3) at room temperature, and electrical connection means (7) between a second end (8) of the superconducting element (4) at high critical temperature and the superconducting application (2) at low critical temperature, according to the invention the conductive means (5) define a metallic surface (9) comprising a first and a second end (10, 11) respectively connected with the first end (6) of the superconducting element (4) at high critical temperature and with l 'connection end (3) at room temperature, the first end (10) of said surface being in contact with a reservoir (12) filled with a cryogenic fluid of temperature equal to or less than 77K.

Description

1 2729501

  HIGH TESION CURRENT AIR A INST = AII O

  BTc SUPERCONDUCTOR AND A CONNECTION END TO

  AMBIENT TEMPERATURE OF A HIGH VOLTAGE CABLE

  The invention relates to a high voltage current supply between a superconducting application at low critical temperature and a connection end to

  ambient temperature of a high voltage power cable.

  In particular, the invention relates to a high-voltage current supply between a superconductive application and a connection end at ambient temperature of a power cable, the said supply comprising at least one superconducting element at high critical temperature, first means of electrical connection between a first end of the superconducting element at high critical temperature and the connection end at room temperature, and second means of electrical connection between a second end of the superconductive element at high

  critical temperature and superconductive application.

  French patent application No. 9301213 discloses a supply of this type. In this document, a device is used comprising a conductor connecting the connection end at room temperature to the critical high temperature superconducting element, which is then connected to the application. The application at critical low temperature is bathed in liquid helium. The conductor is cooled from room temperature to the critical high temperature by being immersed in a container containing liquid nitrogen. The critical high temperature superconducting element is contained in a sealed enclosure at least part of which is in contact with the liquid helium of the application bath. Thus the superconducting element at high critical temperature is cooled to the low critical temperature by conduction. The tank filled with liquid helium and in which the application at low critical temperature is bathed also contains the containers filled with liquid nitrogen and the sealed enclosures surrounding the high-conductive superconducting elements.

critical temperature.

  One of the drawbacks of the above-described supply is the cooling by contact of liquid nitrogen or nitrogen vapors on the conductors. Another drawback is generated by the arrangement and the complex and cumbersome structure of the supply, all the more so when using high current at high voltage. In particular, the tank filled with liquid helium constitutes the enclosure of all the elements of the supply, or the conductors have a too long length generating

  significant losses in alternating current regime.

  A first object of the present invention is to provide a current supply for cooling the

  conductors by thermal conduction.

  Another object of the present invention is to provide an arrangement and structure current supply.

  simplified even at very high voltage.

  To this end, the invention relates to a current supply between a superconductive application at low critical temperature and a connection end at room temperature of a high voltage power cable, said supply comprising at least one superconductive element at high critical temperature. , electrical conductor means between a first end of the high critical temperature superconducting element and the connection end at room temperature, and electrical connection means between a second end of the high critical temperature superconducting element and the superconductive application. According to the invention, the conductive means form a metal surface comprising first and second ends connected respectively with the first end of the superconducting element at high critical temperature and with the connection end at room temperature, the first end of the said surface being in contact with a reservoir filled with a fluid

  cryogenic temperature equal to or less than 77K.

  In one embodiment of the invention, the superconductive installation is placed in a sealed metal tank filled with liquid helium. Said second end of said critical high temperature superconducting element being in contact with at least a portion

of the tank.

  According to a characteristic of the invention, the sealed liquid helium tank containing the superconductive application, the superconductive element at high critical temperature, the cryogenic fluid reservoir, and the metal surface are arranged in a grounded enclosure, and in which there is a high vacuum, the second end of the metal surface passing in a sealed and electrically isolated manner through said grounded metal enclosure, and being connected to the connection end at ambient temperature outside said

  grounded metal enclosure.

  Radiation shields connected to ground, surround the sealed liquid helium tank containing the superconductive application, the superconducting element at high critical temperature, and the metallic surface, at

  inside the grounded metal enclosure.

  Similarly, electrically insulating heat shields are arranged around the metal surface, and near the second end of the metal surface.

  inside the grounded metal enclosure.

  Inside the metal enclosure, the tank filled with cryogenic fluid and the metal tank filled with liquid helium are connected to supply tanks for cryogenic fluid and liquid helium respectively by supply links, said connections electrically insulating supply tank filled with cryogenic fluid and metal tank filled with helium

  liquid from their associated supply tank.

  A first advantage of the present invention is to have eliminated direct contact of the conductors with the

  cryogenic fluid intended to cool them.

  A second advantage is to propose a current supply of a simplified arrangement which does not generate

  prohibitive congestion even at very high voltage.

  Other advantages and features of this

  invention will result from the description which follows in

  reference to the accompanying drawings in which: FIG. 1 is a schematic representation of a

  embodiment of a feed according to the invention.

  Figure 2 is a schematic sectional representation along line II-II of the representation of the

figure 1.

  According to the invention, the aim of the current supply is to bring high or very high voltage current between a superconductive application 2 at low critical temperature (4.2 K) and a connection end 3 of an energy cable

  high voltage at room temperature (300K).

  The supply comprises at least one superconducting element 4 at high critical temperature (77K), electrically conductive means 5 between a first end 6 of the superconducting element 4 at high critical temperature and the connection end 3 at ambient temperature, and electrical connection means 7 between a second end 8 of the high temperature superconducting element 4

  critical and the superconductive application 2.

  According to the invention, the conductive means 5 form a metal surface 9 comprising a first 10 and a second 11 ends connected respectively with the first end 6 of the superconducting element 4 at high critical temperature and with the connection end 3 to

ambient temperature.

  The first end 10 of said surface being in contact with a reservoir 12 filled with a cryogenic fluid

  with a temperature equal to or less than 77K.

  Advantageously, the first end 6 of the superconducting element 4 at high critical temperature is at

  contact of at least part of the reservoir 12.

  Thus, the first end 6 of the superconducting element 4 at high critical temperature and the part of the conductive means 5 constituting the metal surface 9 comprising the first end 10 of the metal surface 9 are cooled by thermal conduction at the temperature of the cryogenic liquid. contained in the reservoir 12, ie 77K. Advantageously, the reservoir 12 is made of a material which is a good thermal conductor.

  such as, for example, without limitation, copper.

  In the embodiment of the invention shown in the figures, the metal surface 9 is a hollow cylinder formed by a plurality of conductors 25, each forming a generator of said cylinder. Drivers are therefore optimized to limit losses in speed

of alternating current.

  According to the invention, the superconductive installation 2 is placed in a sealed metallic tank 13 filled with liquid helium (4.2K). The second end 8 of the superconducting element 4 at high critical temperature is in contact, via the connection means 7, of

liquid helium.

  Thus, the second end 8 of the superconducting element 4 at high critical temperature is cooled by thermal conduction to the temperature of the liquid helium contained in the metal tank 13, that is to say 4.2K. According to a characteristic of the invention, the sealed metal tank 13 filled with liquid helium and comprising the superconductive application 2, the superconductive element 4 at high critical temperature, and the metal surface 9 are arranged in an enclosure 14 placed at the mass, and in which there is a high vacuum (of the order of 10-6 Torr). This high vacuum plays both the role of thermal insulator and electrical insulator between the enclosure 14 to ground and the supply and the application which are at high voltage. This metal enclosure 14 is advantageously

  made of stainless steel, for example 304L.

  The second end 11 of the metal surface 9 passes through a sealed and electrically isolated enclosure the metal enclosure 14 grounded, and is connected to the connection end 3 at ambient temperature outside said metallic enclosure 14 the mass. Insulation and sealing with the metal enclosure 14 can be carried out, without limitation, by an insulating piece 20 of glass or ceramic mounted on an insulator 21 of charged epoxy resin

or tempered glass.

  Inside the grounded metal enclosure 14, radiation shields 30 connected to ground, surround the sealed metal tank 13 filled with liquid helium and comprising the superconductive application 2, the superconductive element 4 at high critical temperature, and the

metal surface 9.

  Similarly inside the grounded metal enclosure, heat shields 31 are arranged around the metal surface 9, and near the second

  end 11 of the metal surface 9.

  Inside the metal enclosure 14, the tank 12 filled with liquid nitrogen and the metal tank 13 filled with liquid helium are connected to supply tanks 17, 18 respectively in liquid nitrogen and in liquid helium by supply links 15, 16. Supply links 15, 16 electrically isolate the tank 12 filled with liquid nitrogen and the metal tank 13 filled with liquid helium from their associated supply tank 17, 18. These insulating supply links can be, without limitation, made of material

  glass-metal or ceramic-metal type.

  The present invention makes it possible to have compact high voltage current leads with minimal losses for high currents under high voltage. Of course, the invention is not limited to the embodiment described and shown, but it is susceptible of numerous variants accessible to those skilled in the art without departing from the invention. In particular, it is possible, without departing from the scope of the invention, to replace any means

by equivalent means.

Claims (7)

  1. High voltage current supply between a superconductive application (2) at low critical temperature (4.2K) and a connection end (3) at room temperature (300K) of a high voltage power cable, the so-called supply comprising at least one superconducting element (4) at high critical temperature (77K), electrically conductive means (5) between a first end (6) of the superconducting element (4) at high critical temperature and the connection end ( 3) at ambient temperature, and electrical connection means (7) between a second end (8) of the superconducting element (4) at high critical temperature and the superconductive application (2) at low critical temperature, characterized in that that the conductive means (5) form a metallic surface (9) comprising first and second ends (10, 11) connected respectively with the first end (6) of the superconductive element (4) at high temp critical temperature and with the connection end (3) at room temperature, the first end (10) of said surface being in contact with a reservoir (12) filled with a cryogenic fluid of temperature equal to or less than 77K 2. Supply according to claim 1 characterized in that the metal surface (13) is a hollow cylinder formed by a plurality of conductors (25), each conductor (25) forming a generator of said cylinder, the reservoir   (12) being contained in the cylinder.   3. Supply according to claim 1 or 2 characterized in that the superconductive installation (2) at low critical temperature, is arranged in a metal tank (13), sealed, filled with liquid helium, the second end (8) of the superconducting element (4) at high critical temperature being in contact via   connection means (7) with liquid helium.   4. Supply according to claim 3 characterized in that the metal tank (13) filled with liquid helium, and comprising the superconductive application (2), the superconductive element (4) at high critical temperature, and the metal surface ( 9) are arranged in a grounded metal enclosure (14), in which there is a high vacuum, the second end (11) of the metal surface (9) passing through said electrically sealed enclosure (14) ) grounded, and being connected to the connection end (3) at room temperature outside said metal enclosure (14) Grounding.   5. Supply according to claim 4 characterized in that inside the metal enclosure (14) grounded, it comprises radiant screens (30) connected to ground, surround the sealed metal tank (13) filled with liquid helium and comprising the superconductive application (2), the superconductive element (4) at high   critical temperature, and the metal surface (9).   6. Supply according to claim 4 or 5 characterized in that inside the metal enclosure (14) grounded, it comprises heat shields (31) electrically insulating, arranged around the metal surface (9 ), and near the second end (11) of the metal surface (9).   7. Brought according to any one of claims 2   6 characterized in that inside the metal enclosure (14), the tank (12) filled with cryogenic fluid at 77K and the metal tank (13) filled with liquid helium are connected to supply tanks (17, 18) respectively in cryogenic fluid at 77K and in liquid helium by supply connections (15, 16), said supply connections (15, 15) electrically isolating the tank (12) and the metal tank (13 )   of their associated supply tank (17, 18).