EP0610131A1 - Feed through connection for superconducting coil - Google Patents

Feed through connection for superconducting coil Download PDF

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Publication number
EP0610131A1
EP0610131A1 EP94400211A EP94400211A EP0610131A1 EP 0610131 A1 EP0610131 A1 EP 0610131A1 EP 94400211 A EP94400211 A EP 94400211A EP 94400211 A EP94400211 A EP 94400211A EP 0610131 A1 EP0610131 A1 EP 0610131A1
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EP
European Patent Office
Prior art keywords
conductors
coil
cryostat
superconductive
leads
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP94400211A
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German (de)
French (fr)
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EP0610131B1 (en
Inventor
Christian Cottevieille
Gerard Bottini
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Alstom SA
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GEC Alsthom Electromecanique SA
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Publication of EP0610131A1 publication Critical patent/EP0610131A1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F6/00—Superconducting magnets; Superconducting coils
    • H01F6/06—Coils, e.g. winding, insulating, terminating or casing arrangements therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F6/00—Superconducting magnets; Superconducting coils
    • H01F6/06—Coils, e.g. winding, insulating, terminating or casing arrangements therefor
    • H01F6/065—Feed-through bushings, terminals and joints
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S336/00—Inductor devices
    • Y10S336/01—Superconductive
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S505/00—Superconductor technology: apparatus, material, process
    • Y10S505/825—Apparatus per se, device per se, or process of making or operating same
    • Y10S505/879—Magnet or electromagnet

Definitions

  • the present invention relates to a connection intended for the electrical supply of a high-voltage superconductive coil, with a high nominal current, of several hundred amperes. It can for example be a current limiter of 63 kV and 1200 Amps; it must be able to withstand 2.2 times its nominal voltage, ie 139kV (IEC71 recommendation).
  • the connection makes it possible to electrically connect the superconductive coil placed in a cryostat within a cryogenic fluid at very low temperature, to a conductor placed outside and being at ambient temperature (300K).
  • the object of the present invention is to provide a connection making it possible to supply high current in a balanced manner to high-voltage superconductive coils.
  • the object of the present invention is a connection for the electrical supply of a transposed superconductive coil.
  • the coil is placed in a cryostat and comprises a plurality of identical superconducting conductors, the accessible ends of which are uniformly distributed in a cylindrical symmetry.
  • the connection is constituted by two current leads composed of a plurality of identical conductors between them comprising a first end and a second end.
  • connection is characterized in that the number of conductors is identical for the two leads and equal to the number of superconductive conductors of the coil; it is also characterized in that the conductors of the leads are arranged regularly and parallel in a cylindrical symmetry with respect to the axis of the coil; it is further characterized in that the feeds are arranged coaxially; and it is finally characterized in that the first end of the conductors of the leads is connected to the superconductive conductors.
  • connection according to the invention does not break the cylindrical symmetry of the coil and it guarantees the balance of the currents.
  • the present invention has the advantage of allowing a balanced supply of the coil, so each superconductive conductor can transport its critical current and be used under optimal conditions.
  • the section total of all the conductors of the input leads on the one hand and the output on the other hand is fixed according to the current to be transported.
  • connection between a conductor of a supply and a superconductive conductor of the coil is made by placing their ends side by side over a length of about 10cm. Then, the conductors of each current supply are connected to the superconductive conductors of the coil by lead-tin type welding, or by magnetoforming.
  • the second end of the conductors of each current supply is secured to a cylindrical conductive part.
  • This part is chosen in shape and size adapted to the voltage level and the current carried.
  • the cylindrical conductive part is made of copper.
  • each of the conductors of the current supply is placed individually inside an electrical insulating tube.
  • These insulating tubes can be made of epoxy glass or a similar material.
  • the tubes containing each conductor individually are arranged in a cylindrical symmetry.
  • a circulation of vapor of the cryogenic fluid ensuring the cooling of the conductors of the current leads is produced inside the insulating tube.
  • these tubes are filled with cryogenic fluid which is surmounted by its vapors.
  • the conductors of each of the feeds are placed inside the double wall of an electrical insulating tube, the two tubes being arranged coaxially.
  • a circulation of vapor of the cryogenic fluid ensuring the cooling of the conductors is carried out inside the double wall of the insulating tubes.
  • the present invention has the advantage that the overall structure of the installation makes it possible to avoid the use of polycarbonate tubes whose dimensions are too penalizing.
  • the conductors of the current leads are of the assembled type comprising several strands, consisting of copper filaments in a cupronickel matrix to reduce losses by induced current, the optimized losses of which are 1.2W / kA at rated current.
  • the conductors of the current leads are of the mixed type comprising, in their part at low temperature, a superconducting element at high critical temperature, as described in French patent n ° 91 07967.
  • connection according to the invention is intended to be applied to a device comprising a superconductive coil placed in a cryostat.
  • the cryostat has an outer wall and an inner metal wall brought to high voltage separated by a vacuum.
  • the outer wall of the cryostat consists of an electrical insulating material, such as a composite.
  • the outer wall of the cryostat carries fins made of insulating material, for example an elastomer loaded or not with glass or ceramic, intended to increase the line of flight.
  • the outer wall of the cryostat is metallic and grounded.
  • the walls are also isolated from each other by a piece of insulating material comprising anticoronas, that is to say toroidal profiles with conductive surface intended to avoid the "crown" effect.
  • This insulating material is for example a ceramic, a composite, or a similar material.
  • the piece of insulating material comprises fins of insulating material which may be identical to or different from that of the piece.
  • a solid electrical insulator is added between the conductors in the hot zone of the cryostat.
  • This insulator may be polycarbonate, polyethylene, epoxy resin, or any similar material, or alternatively this insulator may consist of a chamber containing a liquid insulator of the transformer oil or silicone oil type, or a gaseous insulator such as nitrogen, sulfur hexafluoride, or another gas with better dielectric strength than helium.
  • the enclosure can advantageously be thermally isolated from the vapors of the cryogenic fluid by an appropriate thermal insulator such as vacuum or expanded polystyrene.
  • FIG. 1 is shown a superconductive coil 1 and its two current leads placed in a cryostat 4 within a cryogenic fluid 5, which is liquid helium (4.2K), surmounted by its vapors 6.
  • a cryogenic fluid 5 which is liquid helium (4.2K), surmounted by its vapors 6.
  • Each current supply is made up of four conductors, only two of which are visible and two are hidden, marked 2 and 3 respectively for current input and output,
  • the superconductive coil 1 is shown in an enlarged view in FIG. 2.
  • Four superconductive conductors 101 to 104 are wound side by side to form a superconductive coil.
  • the ends of the superconductive conductors are arranged on either side of the coil in a cylindrical symmetry along the axis 105 of the coil.
  • a first end 101 'to 104' of the superconductive conductors 101 to 104 is connected to the conductors 2 of the current input supply, and a second end 101 '' to 104 '' of the superconductive conductors 101 to 104 is connected to the conductors 3 of the current output supply.
  • an electrical supply circuit 12 located outside (300K) of the cryostat 4, is connected to the coil 1 by the two leads current input and output.
  • the conductors, input 2 on the one hand and output 3 on the other hand, are regularly arranged parallel along the generator of a cylinder coaxial with the axis 105 of the coil.
  • the conductors 2 of the current input supply are secured to a conductive piece 17 preferably made of copper; similarly, the conductors 3 of the current output supply are secured to a conductive piece 18, preferably also made of copper.
  • a conductive piece 17 preferably made of copper similarly, the conductors 3 of the current output supply are secured to a conductive piece 18, preferably also made of copper.
  • These two parts 17 and 18 are connected, and electrically insulated from each other, by a part 20 correctly dimensioned in insulating material, such as a composite or any other similar material.
  • the conductors 2 of the current input supply are connected to the ends 101 'to 104' of the superconductive conductors of the coil 1.
  • This connection 19 is made by placing the end of a conductor 2 and the end 103 'of a superconductive conductor side by side over a length of about 10 cm and joining them by welding, for example of the lead-tin type, or by magnetoforming.
  • the conductors 3 of the current output supply are connected to the ends 101 '' to 104 '' of the superconductive conductors of the coil 1.
  • This connection 19 ' is made in the same way as above between the end of a conductor 3 and the end 101 '' of a superconductive conductor of the coil 1.
  • the conductors 2 and 3 of the current inlet and outlet leads are placed individually in an electrical insulating tube, respectively 13 and 14, perforated in its lower part and immersed in the cryogenic liquid 5 Inside these tubes circulate the vapors 6 of the cryogenic fluid 5 ensuring the cooling of the conductors 2 and 3. Passages are provided in the copper parts 17 and 18, and in the insulating part 20 to allow the escape of the vapors 6.
  • Thermal screens 15 regulate the heat exchange between the cryogenic fluid 5 and the hot zone of the cryostat 4.
  • the electrical insulation between the conductors 2 and 3 of the current inlet and outlet leads is improved by the presence a solid electrical insulator 16 which may consist of a solid material or an enclosure containing an insulating fluid (liquid or gaseous).
  • the cryostat 4 consists of an external wall 7 made of insulating material, such as for example a composite or any other similar material, and of a metallic internal wall 8 brought to high voltage. The two walls are separated by a vacuum 9.
  • the cryostat is provided at its upper part with toric profiles with conductive surface 10 intended to avoid the "crown" effect, and subsequently denoted "anticoronas". Fins 11 made of insulating material, such as for example an elastomer, intended to increase the creepage distance can be arranged on the outer wall, covering part or all of its height.
  • FIG. 4 a variant of Figure 1 is shown in which the outer wall 301 of the cryostat 302 is metallic and grounded.
  • the external wall 301 and the internal metal wall 8 carried at high voltage are electrically insulated on the one hand by the vacuum 9, and on the other hand by a part 303 made of insulating material such as a ceramic or a composite.
  • Room 303 must be fitted with anticoronas 304 adapted to the voltage level.
  • the part 303 can also be fitted with fins of insulating material, for example an elastomer, intended to increase the line of flight and similar in shape to those previously described and shown in FIG. 1.
  • FIG. 5 shows a variant of the connection according to the invention in which the external wall 7 of the cryostat 401 is insulating and provided with fins 11.
  • a metal flange 402 carrying anticoronas 10 electrically connects the internal wall 8 of the cryostat 401 to a cylindrical copper piece 403.
  • Each current supply consists of twelve conductors.
  • the conductors 2 of the input supply on the one hand and 3 of the current output supply on the other hand are regularly arranged parallel along the generator of a cylinder coaxial to the axis 404 of the coil 405.
  • the conductors 2 and 3 are respectively secured to a conductive part 403 and 18, preferably made of copper.
  • the parts 403 and 18 are electrically insulated by a part 409 correctly dimensioned in insulating material, such as a composite or similar material.
  • the second end of the conductors 2 and 3 is connected to the twelve superconductive conductors of the coil 405 according to the technique described above.
  • the detail of these connections 19 and 19 ' is given in FIG. 6, where we see the conductors 2 and 3 connected to the ends 216' and 216 '' of the superconductive conductor 216 of the coil 405.
  • the conductors 2 of the current inlet are placed in the double wall of an electrical insulating tube 406, at the lower part of which there is cryogenic fluid 5 surmounted by its vapors 6.
  • the conductors 3 of the the current output leads are likewise arranged in the double wall of an electrical insulating tube 407.
  • the two tubes 406 and 407 are placed coaxially.
  • the walls of each of the tubes are perforated at their lower part to allow the cryogenic fluid 5 to be introduced into the double wall.
  • the conductors 2 and 3 are cooled by the vapors 6 of the cryogenic fluid 5 which go up along the conductors. Outside and in the space between the tubes, the vapors 6 of the cryogenic fluid 5 also circulate, passing through the double wall of each tube through the passages 408.
  • the vapors 6 escape through passages made in the copper parts 403 and 18, and the insulating part 409.
  • FIG. 7 A section of the cryostat 401 containing the tubes 406 and 407 is presented in FIG. 7. We see there the insulating outer wall 7 and the inner wall 8 of the cryostat separated by the vacuum 9.
  • the double wall of the tubes 406 and 407 respectively surround the conductors 2 and 3.
  • the vapors 6 of the cryogenic fluid are present in the double wall of the tubes 406 and 407, and also around and between the two tubes.
  • FIG. 8 shows a connection according to the invention between a superconductive coil 1 placed in a cryostat 4 (4.2K) and an electrical supply circuit 12 located outside (300K), in the case where the conductors 510 and 511 of each of the two current leads are of the mixed type described in French patent n ° 91 07967.
  • Each metallic conductor 510 or 511 is immersed in a bath of liquid nitrogen 501 surmounted by its vapors. It is connected to a superconducting element 502 at high critical temperature, for example the phase 2212 of an alloy based on bismuth, strontium, calcium and copper oxide, which provides the junction between 4.2K and the intermediate temperature 77K.
  • This element 502 is itself connected to the end 101 ′ of one of the superconductive conductors 101 to 104 of the coil 1 which is in the bath of liquid helium 5 at 4.2K.
  • An insulation vacuum 503 surrounding the nitrogen bath 501 and the superconductor 502 is separated from the helium vapors by a metal wall 504 of low electrical and thermal conductivity, such as 304L stainless steel.
  • the liquid nitrogen bath 501 is contained in a metal container 505, in material similar to the metal wall 504, which is extended in its upper part by an electrical insulating tube 509 made of epoxy glass or a similar material.
  • the contact between the two ends of the superconductive element 502 and the terminals 506 and 507 is made by the method described by GRIVON et al.
  • the upper terminal 506 is thermally insulated from the liquid nitrogen tank by an insulating ceramic 508.
  • This technology makes it possible to reduce the heat losses by a factor of between three and five depending on the nature of the metal conductors.
  • the electrical insulation between the conductors 510 and 511, when the winding passes, is ensured in the hot zone by nitrogen vapors which have a dielectric strength at this temperature ten times greater than that of helium; this is advantageous with a view to developing towards high voltages.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Containers, Films, And Cooling For Superconductive Devices (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Insulators (AREA)
  • Connections Arranged To Contact A Plurality Of Conductors (AREA)
  • Coils Of Transformers For General Uses (AREA)
  • Particle Accelerators (AREA)
  • Linear Motors (AREA)

Abstract

The subject of the present invention is a connection for the electrical feed to a transposed superconducting coil, the said coil being placed in a cryostat and comprising a plurality of superconducting conductors identical to each other, the accessible ends of which are uniformly distributed in cylindrical symmetry, the said connection consisting of two current intakes consisting of a plurality of conductors which are identical to each other comprising a first end and a second end, and being characterised in that the number of the said conductors is identical for the two inlets and equal to the number of the said superconducting conductors of the said coil, in that the said conductors of the said inlets are arranged regularly and parallel along the said cylindrical symmetry with respect to the axis of the said coil, in that the said inlets are arranged coaxially, and in that the said first end of the said conductors of the said inlets is linked to the said superconducting conductors. <IMAGE>

Description

La présente invention concerne une liaison destinée à l'alimentation électrique d'une bobine supraconductrice haute tension, avec un courant nominal élevé, de plusieurs centaines d'ampères. Il peut s'agir par exemple d'un limiteur de courant de 63 kV et 1200 Ampères; celui-ci doit être capable de supporter 2,2 fois sa tension nominale soit 139kV (recommandation CEI71). La liaison permet de relier électriquement la bobine supraconductrice disposée dans un cryostat au sein d'un fluide cryogénique à très basse température, à un conducteur disposé à l'extérieur et se trouvant à température ambiante (300K).The present invention relates to a connection intended for the electrical supply of a high-voltage superconductive coil, with a high nominal current, of several hundred amperes. It can for example be a current limiter of 63 kV and 1200 Amps; it must be able to withstand 2.2 times its nominal voltage, ie 139kV (IEC71 recommendation). The connection makes it possible to electrically connect the superconductive coil placed in a cryostat within a cryogenic fluid at very low temperature, to a conductor placed outside and being at ambient temperature (300K).

Lorsque le courant nominal de la bobine est élevé, on utilise plusieurs conducteurs supraconducteurs. Il se pose alors le problème de réaliser une distribution équilibrée des courants dans les différents conducteurs supraconducteurs. Une solution attrayante est l'utilisation d'une bobine supraconductrice transposée dans laquelle chaque conducteur est placé dans un environnement électromagnétique identique à celui de ses voisins. Dans une telle bobine, les conducteurs sont répartis avec une symétrie cylindrique parfaite. Ceci permet à chaque conducteur de transporter son courant critique, ce courant étant identique pour chacun, ainsi se trouve réalisé l'équilibrage des courants dans la bobine.When the nominal current of the coil is high, several superconductive conductors are used. The problem then arises of achieving a balanced distribution of the currents in the various superconductive conductors. An attractive solution is the use of a transposed superconductive coil in which each conductor is placed in an electromagnetic environment identical to that of its neighbors. In such a coil, the conductors are distributed with perfect cylindrical symmetry. This allows each conductor to transport its critical current, this current being identical for each, thus balancing the currents in the coil is achieved.

L'alimentation classique se fait par deux amenées de courant espacées munies de gaines isolantes en polycarbonate, qui sont mal adaptées à l'alimentation d'une bobine composée de plusieurs conducteurs supraconducteurs. De plus, ce type d'alimentation est pénalisant au point de vue diélectrique. Cette technologie, décrite dans le brevet français n°2 637 728, ne permet pas de dépasser, même temporairement, des tensions de 100kV. Au-delà, il devient difficile de trouver des isolants électriques massifs utilisables à des températures aussi basses, et dont les dimensions permettent de tenir en continu le niveau de tension.Conventional power is supplied by two spaced current leads provided with polycarbonate insulating sheaths, which are ill-suited to powering a coil made up of several superconductive conductors. In addition, this type of supply is penalizing from the dielectric point of view. This technology, described in French Patent No. 2,637,728, does not allow to exceed, even temporarily, voltages of 100kV. Beyond that, it becomes difficult to find massive electrical insulators usable at such low temperatures, and whose dimensions allow to continuously hold the tension level.

L'évolution vers les courants élevés et les hautes tensions des bobines supraconductrices, notamment les limiteurs de courants, impose la réalisation de liaisons d'alimentation répondant à ces exigences.The evolution towards high currents and high voltages of superconducting coils, in particular current limiters, requires the creation of supply links meeting these requirements.

La présente invention a pour but de procurer une liaison permettant d'alimenter en courant élevé de manière équilibrée des bobines supraconductrices à haute tension.The object of the present invention is to provide a connection making it possible to supply high current in a balanced manner to high-voltage superconductive coils.

L'objet de la présente invention est une liaison pour l'alimentation électrique d'une bobine supraconductrice transposée. La bobine est placée dans un cryostat et comprend une pluralité de conducteurs supraconducteurs identiques entre eux dont les extrémités accessibles sont uniformément réparties selon une symétrie cylindrique. La liaison est constituée par deux amenées de courant composées d'une pluralité de conducteurs identiques entre eux comprenant une première extrémité et une seconde extrémité. La liaison est caractérisée en ce que le nombre des conducteurs est identique pour les deux amenées et égal au nombre des conducteurs supraconducteurs de la bobine; elle est aussi caractérisée en ce que les conducteurs des amenées sont disposés régulièrement et parallèlement selon une symétrie cylindrique par rapport à l'axe de la bobine; elle est encore caractérisée en ce que les amenées sont disposées de manière coaxiale; et elle est enfin caractérisée en ce que la première extrémité des conducteurs des amenées est reliée aux conducteurs supraconducteurs.The object of the present invention is a connection for the electrical supply of a transposed superconductive coil. The coil is placed in a cryostat and comprises a plurality of identical superconducting conductors, the accessible ends of which are uniformly distributed in a cylindrical symmetry. The connection is constituted by two current leads composed of a plurality of identical conductors between them comprising a first end and a second end. The connection is characterized in that the number of conductors is identical for the two leads and equal to the number of superconductive conductors of the coil; it is also characterized in that the conductors of the leads are arranged regularly and parallel in a cylindrical symmetry with respect to the axis of the coil; it is further characterized in that the feeds are arranged coaxially; and it is finally characterized in that the first end of the conductors of the leads is connected to the superconductive conductors.

Ainsi la liaison selon l'invention qui vient d'être définie ne rompt pas la symétrie cylindrique de la bobine et elle est garante de l'équilibre des courants. La présente invention a comme avantage de permettre une alimentation équilibrée de la bobine, ainsi chaque conducteur supraconducteur peut transporter son courant critique et être utilisé dans des conditions optimales. La section totale de l'ensemble des conducteurs des amenées d'entrée d'une part et de sortie d'autre part est fixée en fonction du courant à transporter.Thus the connection according to the invention which has just been defined does not break the cylindrical symmetry of the coil and it guarantees the balance of the currents. The present invention has the advantage of allowing a balanced supply of the coil, so each superconductive conductor can transport its critical current and be used under optimal conditions. The section total of all the conductors of the input leads on the one hand and the output on the other hand is fixed according to the current to be transported.

La connexion entre un conducteur d'une amenée et un conducteur supraconducteur de la bobine se fait en plaçant leurs extrémités côte à côte sur une longueur d'environ 10cm. Ensuite, les conducteurs de chaque amenée de courant sont reliés aux conducteurs supraconducteurs de la bobine par soudage de type plomb-étain, ou par magnétoformage.The connection between a conductor of a supply and a superconductive conductor of the coil is made by placing their ends side by side over a length of about 10cm. Then, the conductors of each current supply are connected to the superconductive conductors of the coil by lead-tin type welding, or by magnetoforming.

De préférence, la seconde extrémité des conducteurs de chaque amenée de courant est solidarisée à une pièce conductrice cylindrique. Cette pièce est choisie de forme et de dimension adaptées au niveau de tension et au courant transporté. De préférence, la pièce conductrice cylindrique est en cuivre.Preferably, the second end of the conductors of each current supply is secured to a cylindrical conductive part. This part is chosen in shape and size adapted to the voltage level and the current carried. Preferably, the cylindrical conductive part is made of copper.

Selon une première forme d'exécution, chacun des conducteurs des amenée de courant est placé individuellement à l'intérieur d'un tube isolant électrique. Ces tubes isolants peuvent être en verre époxy ou dans une matière analogue. Les tubes contenant individuellement chaque conducteur sont disposés suivant une symétrie cylindrique. Une circulation de vapeur du fluide cryogénique assurant le refroidissement des conducteurs des amenées de courant est réalisée à l'intérieur du tube isolant. Dans leur partie inférieure, ces tubes sont remplis par le fluide cryogénique qui est surmonté de ses vapeurs. Ces tubes assurent une perte de charge permettant d'obtenir le refroidissement optimum des conducteurs.According to a first embodiment, each of the conductors of the current supply is placed individually inside an electrical insulating tube. These insulating tubes can be made of epoxy glass or a similar material. The tubes containing each conductor individually are arranged in a cylindrical symmetry. A circulation of vapor of the cryogenic fluid ensuring the cooling of the conductors of the current leads is produced inside the insulating tube. In their lower part, these tubes are filled with cryogenic fluid which is surmounted by its vapors. These tubes provide a pressure drop allowing optimum cooling of the conductors.

Selon une seconde forme d'exécution, les conducteurs de chacune des amenées sont placés à l'intérieur de la double paroi d'un tube isolant électrique, les deux tubes étant disposées de manière coaxiale.According to a second embodiment, the conductors of each of the feeds are placed inside the double wall of an electrical insulating tube, the two tubes being arranged coaxially.

Dans ce dernier cas, une circulation de vapeur du fluide cryogénique assurant le refroidissement des conducteurs est réalisée à l'intérieur de la double paroi des tubes isolants.In the latter case, a circulation of vapor of the cryogenic fluid ensuring the cooling of the conductors is carried out inside the double wall of the insulating tubes.

La présente invention a comme avantage que la structure globale de l'installation permet d'éviter la mise en oeuvre de tubes en polycarbonate dont les dimensions sont trop pénalisantes.The present invention has the advantage that the overall structure of the installation makes it possible to avoid the use of polycarbonate tubes whose dimensions are too penalizing.

Selon une variante de réalisation, les conducteurs des amenées de courant sont de type assemblé comprenant plusieurs brins, constitués de filaments de cuivre dans une matrice de cupronickel pour diminuer les pertes par courant induit, dont les pertes optimisées sont de 1,2W/kA au courant nominal.According to an alternative embodiment, the conductors of the current leads are of the assembled type comprising several strands, consisting of copper filaments in a cupronickel matrix to reduce losses by induced current, the optimized losses of which are 1.2W / kA at rated current.

Selon une autre variante de réalisation, les conducteurs des amenées de courant sont de type mixte comportant, dans leur partie à basse température, un élément supraconducteur à haute température critique, tel que décrit dans le brevet français n°91 07967.According to another alternative embodiment, the conductors of the current leads are of the mixed type comprising, in their part at low temperature, a superconducting element at high critical temperature, as described in French patent n ° 91 07967.

La liaison selon l'invention est destinée à être appliquée à un dispositif comportant une bobine supraconductrice placée dans un cryostat. Le cryostat comporte une paroi extérieure et une paroi intérieure métallique portée à la haute tension séparées par du vide.The connection according to the invention is intended to be applied to a device comprising a superconductive coil placed in a cryostat. The cryostat has an outer wall and an inner metal wall brought to high voltage separated by a vacuum.

Selon un premier mode de réalisation, la paroi extérieure du cryostat est constituée d'un matériau isolant électrique, comme un composite. De préférence, la paroi extérieure du cryostat porte des ailettes en matériau isolant, par exemple un élastomère chargé ou non de verre ou de céramique, destinées à augmenter la ligne de fuite.According to a first embodiment, the outer wall of the cryostat consists of an electrical insulating material, such as a composite. Preferably, the outer wall of the cryostat carries fins made of insulating material, for example an elastomer loaded or not with glass or ceramic, intended to increase the line of flight.

Selon un second mode de réalisation, la paroi extérieure du cryostat est métallique et mise à la terre. Dans ce cas, les parois sont en outre isolées l'une de l'autre par une pièce en matériau isolant comportant des anticoronas, c'est à dire des profils toriques à surface conductrice destinés à éviter l'effet "couronne". Ce matériau isolant est par exemple une céramique, un composite, ou un matériau analogue.According to a second embodiment, the outer wall of the cryostat is metallic and grounded. In this case, the walls are also isolated from each other by a piece of insulating material comprising anticoronas, that is to say toroidal profiles with conductive surface intended to avoid the "crown" effect. This insulating material is for example a ceramic, a composite, or a similar material.

Selon une variante de réalisation, la pièce en matériau isolant comporte des ailettes en matériau isolant qui peut être identique ou différent de celui de la pièce.According to an alternative embodiment, the piece of insulating material comprises fins of insulating material which may be identical to or different from that of the piece.

Selon un perfectionnement, un isolant électrique massif est ajouté entre les conducteurs dans la zone chaude du cryostat. Cet isolant peut être du polycarbonate, du polyéthylène, de le résine époxy, ou toute matière analogue, ou bien encore cet isolant peut être constitué d'une enceinte contenant un isolant liquide du type huile de transformateur ou huile silicone, ou un isolant gazeux comme de l'azote, de l'hexafluorure de soufre, ou un autre gaz ayant une meilleure rigidité diélectrique que l'hélium. Dans ce dernier cas, l'enceinte pourra avantageusement être isolée thermiquement des vapeurs du fluide cryogénique par un isolant thermique approprié comme le vide ou le polystyrène expansé.According to an improvement, a solid electrical insulator is added between the conductors in the hot zone of the cryostat. This insulator may be polycarbonate, polyethylene, epoxy resin, or any similar material, or alternatively this insulator may consist of a chamber containing a liquid insulator of the transformer oil or silicone oil type, or a gaseous insulator such as nitrogen, sulfur hexafluoride, or another gas with better dielectric strength than helium. In the latter case, the enclosure can advantageously be thermally isolated from the vapors of the cryogenic fluid by an appropriate thermal insulator such as vacuum or expanded polystyrene.

L'invention sera mieux comprise et d'autres avantages et particularités apparaîtront à la lecture de la description qui va suivre, donnée à titre illustratif et non limitatif, accompagnée des dessins annexés parmi lesquels:

  • la figure 1 représente une liaison selon l'invention entre une bobine supraconductrice, placée dans un cryostat, et un circuit d'alimentation électrique situé à l'extérieur du cryostat, dans le cas où chacun des conducteurs est placé dans un tube isolant électrique,
  • la figure 2 est une vue agrandie de la bobine supraconductrice de la figure 1,
  • la figure 3 est une détail de la connexion conducteur supraconducteur/conducteur des amenées de courant de la figure 1,
  • la figure 4, analogue à la figure 1, montre une variante où l'enceinte externe du cryostat est constituée d'un matériau métallique,
  • la figure 5, analogue à la figure 1, montre une variante de la liaison selon l'invention où les conducteurs sont disposés dans la double paroi d'un tube isolant électrique,
  • la figure 6 est un détail de la connexion conducteur supraconducteur/conducteur des amenées de courant de la figure 5,
  • la figure 7 est une coupe de la liaison selon la ligne VII-VII de la figure 5
  • la figure 8, analogue à la figure 1, représente une liaison selon l'invention entre un élément supraconducteur placé dans un cryostat et un circuit d'alimentation électrique situé à l'extérieur du cryostat dans le cas où chacun des conducteurs est du type mixte décrit dans le brevet français n°91 07967.
The invention will be better understood and other advantages and features will appear on reading the description which follows, given by way of illustration and not limitation, accompanied by the appended drawings among which:
  • FIG. 1 represents a connection according to the invention between a superconductive coil, placed in a cryostat, and an electrical supply circuit situated outside the cryostat, in the case where each of the conductors is placed in an electrical insulating tube,
  • FIG. 2 is an enlarged view of the superconductive coil of FIG. 1,
  • FIG. 3 is a detail of the superconducting conductor / conductor connection of the current leads of FIG. 1,
  • FIG. 4, similar to FIG. 1, shows a variant in which the external enclosure of the cryostat is made of a metallic material,
  • Figure 5, similar to Figure 1, shows a variant of the connection according to the invention where the conductors are arranged in the double wall of an electrical insulating tube,
  • FIG. 6 is a detail of the superconducting conductor / conductor connection of the current leads of FIG. 5,
  • Figure 7 is a section of the connection along line VII-VII of Figure 5
  • FIG. 8, similar to FIG. 1, represents a connection according to the invention between a superconductive element placed in a cryostat and an electrical supply circuit situated outside the cryostat in the case where each of the conductors is of the mixed type described in French patent n ° 91 07967.

Sur la figure 1 est représentée une bobine supraconductrice 1 et ses deux amenées de courant placées dans un cryostat 4 au sein d'un fluide cryogénique 5, qui est de l'hélium liquide (4,2K), surmonté de ses vapeurs 6. Chaque amenée de courant est composée de quatre conducteurs, dont deux seulement sont visibles et deux sont cachés, notés 2 et 3 respectivement pour l'entrée et la sortie du courant,In Figure 1 is shown a superconductive coil 1 and its two current leads placed in a cryostat 4 within a cryogenic fluid 5, which is liquid helium (4.2K), surmounted by its vapors 6. Each current supply is made up of four conductors, only two of which are visible and two are hidden, marked 2 and 3 respectively for current input and output,

La bobine supraconductrice 1 est représentée en vue agrandie sur la figure 2. Quatre conducteurs supraconducteurs 101 à 104 s'enroulent côte à côte pour constituer un bobinage supraconducteur. Les extrémités des conducteurs supraconducteurs sont disposées de part et d'autre de la bobine selon une symétrie cylindrique suivant l'axe 105 de la bobine. Une première extrémité 101' à 104' des conducteurs supraconducteurs 101 à 104 est reliée aux conducteurs 2 de l'amenée d'entrée du courant, et une seconde extrémité 101'' à 104'' des conducteurs supraconducteurs 101 à 104 est reliée aux conducteurs 3 de l'amenée de sortie du courant.The superconductive coil 1 is shown in an enlarged view in FIG. 2. Four superconductive conductors 101 to 104 are wound side by side to form a superconductive coil. The ends of the superconductive conductors are arranged on either side of the coil in a cylindrical symmetry along the axis 105 of the coil. A first end 101 'to 104' of the superconductive conductors 101 to 104 is connected to the conductors 2 of the current input supply, and a second end 101 '' to 104 '' of the superconductive conductors 101 to 104 is connected to the conductors 3 of the current output supply.

Sur la figure 1, on peut voir qu'un circuit d'alimentation électrique 12, situé à l'extérieur (300K) du cryostat 4, est raccordé à la bobine 1 par les deux amenées d'entrée et de sortie du courant. Les conducteurs, d'entrée 2 d'une part et de sortie 3 d'autre part, sont régulièrement disposés parallèlement suivant la génératrice d'un cylindre coaxial avec l'axe 105 de la bobine.In Figure 1, we can see that an electrical supply circuit 12, located outside (300K) of the cryostat 4, is connected to the coil 1 by the two leads current input and output. The conductors, input 2 on the one hand and output 3 on the other hand, are regularly arranged parallel along the generator of a cylinder coaxial with the axis 105 of the coil.

A une première extrémité, les conducteurs 2 de l'amenée d'entrée de courant sont solidarisés avec une pièce conductrice 17 de préférence en cuivre; de même les conducteurs 3 de l'amenée de sortie de courant sont solidarisées avec une pièce conductrice 18, de préférence également en cuivre. Ces deux pièces 17 et 18 sont reliées, et isolées électriquement l'une de l'autre, par une pièce 20 correctement dimensionnée en matériau isolant, comme un composite ou tout autre matériau analogue.At a first end, the conductors 2 of the current input supply are secured to a conductive piece 17 preferably made of copper; similarly, the conductors 3 of the current output supply are secured to a conductive piece 18, preferably also made of copper. These two parts 17 and 18 are connected, and electrically insulated from each other, by a part 20 correctly dimensioned in insulating material, such as a composite or any other similar material.

Comme le montre de manière plus détaillée la figure 3, à une seconde extrémité, les conducteurs 2 de l'amenée d'entrée de courant sont connectés aux extrémités 101' à 104' des conducteurs supraconducteurs de la bobine 1. Cette connexion 19 est réalisée en plaçant l'extrémité d'un conducteur 2 et l'extrémité 103' d'un conducteur supraconducteur côte à côte sur une longueur d'environ 10cm et en les solidarisant par soudage, par exemple de type plomb-étain, ou par magnétoformage. De même à une seconde extrémité, les conducteurs 3 de l'amenée de sortie de courant sont connectés aux extrémités 101'' à 104'' des conducteurs supraconducteurs de la bobine 1. Cette connexion 19' est réalisée de la même manière que précédemment entre l'extrémité d'un conducteur 3 et l'extrémité 101'' d'un conducteur supraconducteur de la bobine 1.As shown in more detail in Figure 3, at a second end, the conductors 2 of the current input supply are connected to the ends 101 'to 104' of the superconductive conductors of the coil 1. This connection 19 is made by placing the end of a conductor 2 and the end 103 'of a superconductive conductor side by side over a length of about 10 cm and joining them by welding, for example of the lead-tin type, or by magnetoforming. Likewise at a second end, the conductors 3 of the current output supply are connected to the ends 101 '' to 104 '' of the superconductive conductors of the coil 1. This connection 19 'is made in the same way as above between the end of a conductor 3 and the end 101 '' of a superconductive conductor of the coil 1.

Dans le cas représenté par la figure 1, les conducteurs 2 et 3 des amenées d'entrée et de sortie du courant sont placés individuellement dans un tube isolant électrique, respectivement 13 et 14, perforé dans sa partie basse et plongeant dans le liquide cryogénique 5. A l'intérieur de ces tubes circulent les vapeurs 6 du fluide cryogénique 5 assurant le refroidissement des conducteurs 2 et 3. Des passages sont ménagés dans les pièces en cuivre 17 et 18, et dans la pièce isolante 20 pour permettre l'échappement des vapeurs 6.In the case represented by FIG. 1, the conductors 2 and 3 of the current inlet and outlet leads are placed individually in an electrical insulating tube, respectively 13 and 14, perforated in its lower part and immersed in the cryogenic liquid 5 Inside these tubes circulate the vapors 6 of the cryogenic fluid 5 ensuring the cooling of the conductors 2 and 3. Passages are provided in the copper parts 17 and 18, and in the insulating part 20 to allow the escape of the vapors 6.

L'isolement électrique entre les conducteurs 2 et 3 des amenées d'entrée et de sortie du courant, lorsque le bobinage transite, est assuré dans la zone chaude par de l'hélium gazeux. Des écrans thermiques 15 régularisent l'échange thermique entre le fluide cryogénique 5 et la zone chaude du cryostat 4. De plus, l'isolement électrique entre les conducteurs 2 et 3 des amenées d'entrée et de sortie du courant est amélioré par la présence d'un isolant électrique 16 massif qui peut être constitué d'un matériau massif ou d'une enceinte contenant un fluide isolant (liquide ou gazeux).The electrical insulation between the conductors 2 and 3 of the current input and output leads, when the winding is in transit, is ensured in the hot zone by gaseous helium. Thermal screens 15 regulate the heat exchange between the cryogenic fluid 5 and the hot zone of the cryostat 4. In addition, the electrical insulation between the conductors 2 and 3 of the current inlet and outlet leads is improved by the presence a solid electrical insulator 16 which may consist of a solid material or an enclosure containing an insulating fluid (liquid or gaseous).

Le cryostat 4 est constitué d'une paroi externe 7 en matériau isolant, comme par exemple un composite ou tout autre matériau analogue, et d'une paroi interne métallique 8 portée à la haute tension. Les deux parois sont séparées par le vide 9. Le cryostat est munis à sa partie supérieure de profils toriques à surface conductrice 10 destinés à éviter l'effet "couronne", et notés par la suite "anticoronas". Des ailettes 11 en matériau isolant, comme par exemple un élastomère, destinées à augmenter la ligne de fuite peuvent être disposées sur la paroi extérieure, couvrant une partie ou la totalité de sa hauteur.The cryostat 4 consists of an external wall 7 made of insulating material, such as for example a composite or any other similar material, and of a metallic internal wall 8 brought to high voltage. The two walls are separated by a vacuum 9. The cryostat is provided at its upper part with toric profiles with conductive surface 10 intended to avoid the "crown" effect, and subsequently denoted "anticoronas". Fins 11 made of insulating material, such as for example an elastomer, intended to increase the creepage distance can be arranged on the outer wall, covering part or all of its height.

Sur la figure 4, on a représenté une variante de la figure 1 dans laquelle la paroi extérieure 301 du cryostat 302 est métallique et mise à la terre. Dans ce cas, la paroi externe 301 et la paroi interne métallique 8 portée à haute tension sont électriquement isolées d'une part par le vide 9, et d'autre part par une pièce 303 en matériau isolant comme une céramique ou un composite. La pièce 303 doit être équipée d'anticoronas 304 adaptés au niveau de tension. La pièce 303 peut en outre être équipée d'ailettes en matériau isolant, par exemple un élastomère, destinées à augmenter la ligne de fuite et de forme similaire à celles précédemment décrites et représentées sur la figure 1.In Figure 4, a variant of Figure 1 is shown in which the outer wall 301 of the cryostat 302 is metallic and grounded. In this case, the external wall 301 and the internal metal wall 8 carried at high voltage are electrically insulated on the one hand by the vacuum 9, and on the other hand by a part 303 made of insulating material such as a ceramic or a composite. Room 303 must be fitted with anticoronas 304 adapted to the voltage level. The part 303 can also be fitted with fins of insulating material, for example an elastomer, intended to increase the line of flight and similar in shape to those previously described and shown in FIG. 1.

La figure 5 montre une variante de la liaison selon l'invention dans laquelle la paroi externe 7 du cryostat 401 est isolante et munie d'ailettes 11. Une bride métallique 402 portant des anticoronas 10 relie électriquement la paroi interne 8 du cryostat 401 à une pièce de cuivre cylindrique 403. Chaque amenée de courant se compose de douze conducteurs. Les conducteurs 2 de l'amenée d'entrée d'une part et 3 de l'amenée de sortie du courant d'autre part sont régulièrement disposés parallèlement suivant la génératrice d'un cylindre coaxial à l'axe 404 de la bobine 405. A une première extrémité, les conducteurs 2 et 3 sont respectivement solidarisés avec une pièce conductrice 403 et 18, de préférence en cuivre. Les pièces 403 et 18 sont isolées électriquement par une pièce 409 correctement dimensionnée en matériau isolant, tel qu'un composite ou un matériau analogue.FIG. 5 shows a variant of the connection according to the invention in which the external wall 7 of the cryostat 401 is insulating and provided with fins 11. A metal flange 402 carrying anticoronas 10 electrically connects the internal wall 8 of the cryostat 401 to a cylindrical copper piece 403. Each current supply consists of twelve conductors. The conductors 2 of the input supply on the one hand and 3 of the current output supply on the other hand are regularly arranged parallel along the generator of a cylinder coaxial to the axis 404 of the coil 405. At a first end, the conductors 2 and 3 are respectively secured to a conductive part 403 and 18, preferably made of copper. The parts 403 and 18 are electrically insulated by a part 409 correctly dimensioned in insulating material, such as a composite or similar material.

La seconde extrémité des conducteurs 2 et 3 est connectée aux douze conducteurs supraconducteurs de la bobine 405 suivant la technique décrite ci-dessus. Le détail de ces connexions 19 et 19' est donné par la figure 6, où on voit les conducteurs 2 et 3 reliés aux extrémités 216' et 216'' du conducteur supraconducteur 216 de la bobine 405.The second end of the conductors 2 and 3 is connected to the twelve superconductive conductors of the coil 405 according to the technique described above. The detail of these connections 19 and 19 'is given in FIG. 6, where we see the conductors 2 and 3 connected to the ends 216' and 216 '' of the superconductive conductor 216 of the coil 405.

Les conducteurs 2 de l'amenée d'entrée du courant sont placés dans la double paroi d'un tube isolant électrique 406, à la partie inférieure de laquelle se trouve du fluide cryogénique 5 surmonté de ses vapeurs 6. Les conducteurs 3 de l'amenée de sortie du courant sont de la même façon disposés dans la double paroi d'un tube isolant électrique 407. Les deux tubes 406 et 407 sont placés de manière coaxiale. Les parois de chacun des tubes sont perforées à leur partie inférieure pour permettre au fluide cryogénique 5 de s'introduire dans la double paroi. Le refroidissement des conducteurs 2 et 3 est assuré par les vapeurs 6 du fluide cryogénique 5 qui remontent le long des conducteurs. A l'extérieur et dans l'intervalle existant entre les tubes circulent également les vapeurs 6 du fluide cryogénique 5 qui traversent la double paroi de chaque tube par les passages 408. Les vapeurs 6 s'échappent par des passages ménagés dans les pièces en cuivre 403 et 18, et la pièce isolante 409.The conductors 2 of the current inlet are placed in the double wall of an electrical insulating tube 406, at the lower part of which there is cryogenic fluid 5 surmounted by its vapors 6. The conductors 3 of the the current output leads are likewise arranged in the double wall of an electrical insulating tube 407. The two tubes 406 and 407 are placed coaxially. The walls of each of the tubes are perforated at their lower part to allow the cryogenic fluid 5 to be introduced into the double wall. The conductors 2 and 3 are cooled by the vapors 6 of the cryogenic fluid 5 which go up along the conductors. Outside and in the space between the tubes, the vapors 6 of the cryogenic fluid 5 also circulate, passing through the double wall of each tube through the passages 408. The vapors 6 escape through passages made in the copper parts 403 and 18, and the insulating part 409.

Une coupe du cryostat 401 contenant les tubes 406 et 407 est présentée sur la figure 7. On y voit la paroi extérieure isolante 7 et la paroi intérieure 8 du cryostat séparées par le vide 9. La double paroi des tubes 406 et 407 entourent respectivement les conducteurs 2 et 3. Les vapeurs 6 du fluide cryogénique sont présentes dans la double paroi des tubes 406 et 407, et également autour et entre les deux tubes.A section of the cryostat 401 containing the tubes 406 and 407 is presented in FIG. 7. We see there the insulating outer wall 7 and the inner wall 8 of the cryostat separated by the vacuum 9. The double wall of the tubes 406 and 407 respectively surround the conductors 2 and 3. The vapors 6 of the cryogenic fluid are present in the double wall of the tubes 406 and 407, and also around and between the two tubes.

Enfin la figure 8 montre une liaison selon l'invention entre une bobine supraconductrice 1 placée dans un cryostat 4 (4,2K) et un circuit d'alimentation électrique 12 situé à l'extérieur (300K), dans le cas où les conducteurs 510 et 511 de chacune des deux amenées de courant sont du type mixte décrit dans le brevet français n°91 07967. Chaque conducteur métallique 510 ou 511 est plongé dans un bain d'azote liquide 501 surmonté de ses vapeurs. Il est connecté à un élément supraconducteur 502 à haute température critique, par exemple la phase 2212 d'un alliage à base de bismuth, strontium, calcium et oxyde de cuivre, qui assure la jonction entre 4,2K et la température intermédiaire 77K. Cet élément 502 est lui-même connecté à l'extrémité 101' de l'un des conducteurs supraconducteurs 101 à 104 de la bobine 1 qui se trouve dans le bain d'hélium liquide 5 à 4,2K. Un vide d'isolation 503 entourant le bain d'azote 501 et le supraconducteur 502 est séparé des vapeurs d'hélium 6 par une paroi métallique 504 de faibles conductivité électrique et thermique, comme l'acier inoxydable 304L. Le bain d'azote liquide 501 est contenu dans un récipient métallique 505, en matière similaire à la paroi métallique 504, qui est prolongé dans sa partie haute par un tube isolant électrique 509 en verre époxy ou dans une matière analogue. Le contact entre les deux extrémités de l'élément supraconducteur 502 et les bornes 506 et 507 est réalisé par la méthode décrite par GRIVON et al. dans "YBaCuO current lead for liquid hélium température applications" 1990 Applied Superconductivity Conference. La borne supérieure 506 est isolée thermiquement du réservoir d'azote liquide par une céramique isolante 508. Cette technologie permet de diminuer les pertes thermiques d'un facteur compris entre trois et cinq suivant la nature des conducteurs métalliques. En outre l'isolation électrique entre les conducteurs 510 et 511, lorsque le bobinage transite, est assurée dans la zone chaude par les vapeurs d'azote qui possèdent à cette température une rigidité diélectrique dix fois supérieure à celle de l'hélium; ceci est avantageux en vue d'une évolution vers les hautes tensions.Finally, FIG. 8 shows a connection according to the invention between a superconductive coil 1 placed in a cryostat 4 (4.2K) and an electrical supply circuit 12 located outside (300K), in the case where the conductors 510 and 511 of each of the two current leads are of the mixed type described in French patent n ° 91 07967. Each metallic conductor 510 or 511 is immersed in a bath of liquid nitrogen 501 surmounted by its vapors. It is connected to a superconducting element 502 at high critical temperature, for example the phase 2212 of an alloy based on bismuth, strontium, calcium and copper oxide, which provides the junction between 4.2K and the intermediate temperature 77K. This element 502 is itself connected to the end 101 ′ of one of the superconductive conductors 101 to 104 of the coil 1 which is in the bath of liquid helium 5 at 4.2K. An insulation vacuum 503 surrounding the nitrogen bath 501 and the superconductor 502 is separated from the helium vapors by a metal wall 504 of low electrical and thermal conductivity, such as 304L stainless steel. The liquid nitrogen bath 501 is contained in a metal container 505, in material similar to the metal wall 504, which is extended in its upper part by an electrical insulating tube 509 made of epoxy glass or a similar material. The contact between the two ends of the superconductive element 502 and the terminals 506 and 507 is made by the method described by GRIVON et al. in "YBaCuO current lead for liquid helium temperature applications" 1990 Applied Superconductivity Conference. The upper terminal 506 is thermally insulated from the liquid nitrogen tank by an insulating ceramic 508. This technology makes it possible to reduce the heat losses by a factor of between three and five depending on the nature of the metal conductors. In addition, the electrical insulation between the conductors 510 and 511, when the winding passes, is ensured in the hot zone by nitrogen vapors which have a dielectric strength at this temperature ten times greater than that of helium; this is advantageous with a view to developing towards high voltages.

Bien entendu la présente invention n'est pas limitée aux modes de réalisation décrits et représentés, mais elle est susceptible de nombreuses variantes accessibles à l'homme de l'art sans que l'on ne s'écarte de l'esprit de l'invention. En particulier, on pourra sans sortir du cadre de l'invention remplacer tout moyen par un moyen équivalent.Of course, the present invention is not limited to the embodiments described and shown, but it is capable of numerous variants accessible to those skilled in the art without departing from the spirit of the invention. In particular, without going beyond the scope of the invention, any means can be replaced by equivalent means.

Claims (17)

1./ Liaison pour l'alimentation électrique d'une bobine supraconductrice transposée, ladite bobine étant placée dans un cryostat et comprenant une pluralité de conducteurs supraconducteurs identiques entre eux dont les extrémités accessibles sont uniformément réparties selon une symétrie cylindrique, ladite liaison étant constituée par deux amenées de courant composées d'une pluralité de conducteurs identiques entre eux comprenant une première extrémité et une seconde extrémité, et étant caractérisée en ce que le nombre desdits conducteurs est identique pour les deux amenées et égal au nombre desdits conducteurs supraconducteurs de ladite bobine, en ce que lesdits conducteurs desdites amenées sont disposés régulièrement et parallèlement selon ladite symétrie cylindrique par rapport à l'axe de ladite bobine, en ce que lesdites amenées sont disposées de manière coaxiale, et en ce que ladite première extrémité desdits conducteurs desdites amenées est reliée auxdits conducteurs supraconducteurs. 1. / Connection for the electrical supply of a transposed superconductive coil, said coil being placed in a cryostat and comprising a plurality of identical superconductive conductors whose accessible ends are uniformly distributed in a cylindrical symmetry, said connection being constituted by two current leads composed of a plurality of identical conductors between them comprising a first end and a second end, and being characterized in that the number of said conductors is identical for the two leads and equal to the number of said superconductive conductors of said coil, in that said conductors of said leads are regularly and parallel arranged in said cylindrical symmetry with respect to the axis of said coil, in that said leads are arranged coaxially, and in that said first end of said conductors of said leads is connected to said superconductive conductors. 2./ Liaison selon l'une des revendications précédentes, caractérisée par le fait que lesdits conducteurs de chaque amenée de courant sont reliés auxdits conducteurs supraconducteurs de ladite bobine par soudage ou par magnétoformage. 2. / Connection according to one of the preceding claims, characterized in that said conductors of each current supply are connected to said superconductive conductors of said coil by welding or by magnetoforming. 3./ Liaison selon l'une des revendications précédentes, caractérisée par le fait que ladite seconde extrémité desdits conducteurs de chaque amenée de courant est solidarisée à une pièce conductrice cylindrique. 3. / Connection according to one of the preceding claims, characterized in that said second end of said conductors of each current supply is secured to a cylindrical conductive part. 4./ Liaison selon la revendication 3, caractérisée par le fait que ladite pièce conductrice cylindrique est en cuivre. 4. / Connection according to claim 3, characterized in that said cylindrical conductive part is made of copper. 5./ Liaison selon l'une des revendications précédentes, caractérisée par le fait que chacun desdits conducteurs desdites amenées de courant est placé individuellement à l'intérieur d'un tube isolant électrique. 5. / Connection according to one of the preceding claims, characterized in that each of said conductors of said current leads is placed individually inside an electrical insulating tube. 6./ Liaison selon la revendication 5, caractérisée par le fait qu'une circulation de vapeur du fluide cryogénique assurant le refroidissement desdits conducteurs desdites amenées de courant est réalisée à l'intérieur dudit tube isolant. 6. / Connection according to claim 5, characterized in that a circulation of vapor of the cryogenic fluid ensuring the cooling of said conductors of said current leads is produced inside said insulating tube. 7./ Liaison selon l'une des revendications 1 à 4, caractérisée par le fait que lesdits conducteurs composant chacune desdites amenées sont placés à l'intérieur de la double paroi d'un tube isolant électrique, les deux tubes étant disposées de manière coaxiale. 7. / Connection according to one of claims 1 to 4, characterized in that said conductors making up each of said feeds are placed inside the double wall of an electrical insulating tube, the two tubes being arranged coaxially . 8./ Liaison selon la revendication 7, caractérisée par le fait qu'une circulation de vapeur du fluide cryogénique assurant le refroidissement desdits conducteurs desdites amenées de courant est réalisée à l'intérieur de la double paroi desdits tubes isolants. 8. / Connection according to claim 7, characterized in that a circulation of vapor of the cryogenic fluid ensuring the cooling of said conductors of said current leads is produced inside the double wall of said insulating tubes. 9./ Liaison selon l'une des revendications précédentes, caractérisée par le fait que lesdits conducteurs desdites amenées de courant sont de type assemblé comprenant plusieurs brins constitués de filaments de cuivre dans une matrice de cupronickel. 9. / Connection according to one of the preceding claims, characterized in that said conductors of said current leads are of the assembled type comprising several strands made of copper filaments in a cupronickel matrix. 10./ Liaison selon l'une des revendications 5 et 6, caractérisée par le fait que lesdits conducteurs sont de type mixte comportant, dans leur partie à basse température, un élément supraconducteur à haute température critique. 10./ Connection according to one of claims 5 and 6, characterized in that said conductors are of mixed type comprising, in their part at low temperature, a superconductive element at high critical temperature. 11./ Application de la liaison selon l'une des revendications précédentes à un dispositif comportant une bobine supraconductrice placée dans un cryostat, caractérisée par le fait que ledit cryostat comporte une paroi extérieure et une paroi intérieure métallique portée à la haute tension, lesdites parois étant séparées par du vide. 11./ Application of the connection according to one of the preceding claims to a device comprising a superconductive coil placed in a cryostat, characterized in that said cryostat has an outer wall and an inner metal wall brought to high voltage, said walls being separated by a vacuum. 12./ Application selon la revendication 11, caractérisée par le fait que ladite paroi extérieure dudit cryostat est constituée d'un matériau isolant électrique. 12./ Application according to claim 11, characterized in that said outer wall of said cryostat consists of an electrically insulating material. 13./ Application selon la revendication 12, caractérisée par le fait que ladite paroi extérieure porte des ailettes en matériau isolant. 13./ Application according to claim 12, characterized in that said outer wall carries fins of insulating material. 14./ Application selon la revendication 11, caractérisée par le fait que ladite paroi extérieure dudit cryostat est métallique. 14./ Application according to claim 11, characterized in that said outer wall of said cryostat is metallic. 15./ Application selon la revendication 14, caractérisée par le fait que lesdites parois dudit cryostat sont en outre isolées l'une de l'autre par une pièce en matériau isolant comportant des anticoronas. 15./ Application according to claim 14, characterized in that said walls of said cryostat are further isolated from each other by a piece of insulating material comprising anticoronas. 16./ Application selon la revendication 15, caractérisée par le fait que ladite pièce en matériau isolant comporte en outre des ailettes en matériau isolant. 16./ Application according to claim 15, characterized in that said piece of insulating material further comprises fins of insulating material. 17./ Application selon la revendication 11, caractérisée par le fait qu'un isolant électrique massif est ajouté entre les conducteurs dans la zone chaude dudit cryostat. 17./ Application according to claim 11, characterized in that a solid electrical insulator is added between the conductors in the hot zone of said cryostat.
EP94400211A 1993-02-04 1994-02-01 Feed through connection for superconducting coil Expired - Lifetime EP0610131B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9301213A FR2701157B1 (en) 1993-02-04 1993-02-04 Supply link for superconductive coil.
FR9301213 1993-02-04

Publications (2)

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EP0610131A1 true EP0610131A1 (en) 1994-08-10
EP0610131B1 EP0610131B1 (en) 1997-07-16

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EP94400211A Expired - Lifetime EP0610131B1 (en) 1993-02-04 1994-02-01 Feed through connection for superconducting coil

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US (1) US5436606A (en)
EP (1) EP0610131B1 (en)
AT (1) ATE155607T1 (en)
DE (1) DE69404178T2 (en)
ES (1) ES2104293T3 (en)
FR (1) FR2701157B1 (en)

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US8739396B2 (en) * 2010-06-17 2014-06-03 Varian Semiconductor Equipment Associates, Inc. Technique for limiting transmission of fault current
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FR2729501A1 (en) * 1995-01-17 1996-07-19 Gec Alsthom Electromec HIGH VOLTAGE CURRENT BETWEEN A BTC SUPERCONDUCTING INSTALLATION AND AN AMBIENT TEMPERATURE CONNECTION END OF A HIGH VOLTAGE CABLE
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Also Published As

Publication number Publication date
FR2701157A1 (en) 1994-08-05
DE69404178D1 (en) 1997-08-21
FR2701157B1 (en) 1995-03-31
ATE155607T1 (en) 1997-08-15
DE69404178T2 (en) 1997-10-30
EP0610131B1 (en) 1997-07-16
ES2104293T3 (en) 1997-10-01
US5436606A (en) 1995-07-25

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