DE1811679A1 - End connection for superconducting coaxial cable - Google Patents

Description

British Insulated Callender's Cables Limited

21, Bloomsbury Street, L ο η d ο η, W.G.I., England

For this application, the priority will be taken from the UK Patent application Br. 54-609 / 67 dated November 30, 1967 claimed

End connection for superconducting coaxial cables

The invention relates to end connections for superconducting coaxial cables for the transmission of very high powers for high voltages, the term "cable" used below also including busbars. A superconducting one Cable is a cable in which when the cable is loaded

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the load-bearing conductors are kept in the superconductive state. Preferred types of superconducting coaxial cables are in the associated German patent application P 17 65 457.8 of May 22, 1968 by the same applicant.

The end termination according to the invention can be connected to a superconducting cable, wherein two or more load-carrying conductors are arranged coaxially innerhal'b a cryogenic envelope and separated from each other and from the sheath ¹ by evacuated annular spaces. Lines for a cooling medium can be formed in the conductors or provided on them, and in the latter case they can under certain circumstances act or be used as spacers between the conductors. Where this arrangement is not appropriate, separate thermally and / or electrically insulating spacers are used. The cryogenic envelope can be of the embodiment which is described in the associated German patent application P 17 51 656.8 of July 3, 1968.

It is an object of the invention to provide an end connector having a high voltage end with which α electrical connections can be made and which works at room temperature.

The end connection according to the invention is composed from a tubular insulating sheath attached to one end is sealed to the cryogenic envelope of the cable and to a coaxial connector at the other end, of a number of coaxial conductors, each at one end with one of the Conductive parts of the coaxial connection connected or formed in one piece with this and at the other end with a the conductors of the cable are connected, further insulating spacing and vacuum sealing means between the

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conductive parts of the coaxial connection and from a tubular insulating sheath of the end connection built-in device, which an axial movement of the coaxial connector to and from the cable end away due to temperature change in the coaxial conductors of the end connector. The connection between the coaxial conductors the connector and the cable ladders contains a heat shield to inhibit heat transfer through direct radiation in the longitudinal direction from the conductors of the connector to the cable conductors; this heat shield will hereinafter referred to as longitudinal heat shield.

The longitudinal heat shield is preferably provided by a special design of the conductors of the cable and / or the end connection achieved; for example, the conductors may increase in diameter to a maximum and then again decrease in diameter to give each of the evacuated annuli between them a sinusoidal shape such that none unrestrained or uninterrupted straight line in the annulus, with one of its ends between the cable ladders and the other their ends between the conductors of the connection can lie. Usually the conductors have the end connection a round cross-section, the sinusoidal shape should be such that no unrestrained or uninterrupted right cylindrical or frustoconical surface in the annulus, with the one their ends between the cable ladders and the other of theirs Ends between the conductors of the connection, may lie. Since each of the conductors of the connection is usually one sizeable has a larger diameter than that of the cable conductor to which it is connected, the sinusoidal Because of this, an additional curved section can easily be given by first determining the diameter of each conductor increased from the cable conductor diameter and then its diameter is reduced in the described way, and that finally its diameter is increased again to the diameter of the corresponding conductor of the connection.

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However, it is preferred to have some of the space between Use the inner conductor of the end connection to create a Common supply line for supplying the cryogenic medium to cooling lines within or between the cable conductors or both after such lines and after cooling lines within or between the conductors of the end connection. The common supply line ends, preferably in one Collecting space, which is located within the intermediate temperature zone and forms part of it, which in turn forms a Forms part of the longitudinal heat shield, which is preferably a spherical collecting space from which Distribution lines made of insulating material extend radially after the conductors. The collecting space forms part of the Longitudinal thermal shield, as it extends from the inner surface of the curved part of the inner conductor in the intermediate temperature zone is spaced apart and preferably runs substantially parallel thereto to form a vacuum space of sinusoidal shape, such as defined above, to form.

Of the radial distribution lines, part of the cryogenic Medium flow along the cable and another part back along the end connection (via reducing valves), however, separate lines for distributing the medium may be made into each of the cable and end-connector conductors are provided.

In addition to the device which creates an axial movement between the coaxial connector and the cable, as already mentioned, allows, it is necessary to provide a device for receiving or compensating for an axial movement between different other parts to be provided, namely the common supply line and the sleeve, where they fit into the end fitting and the distribution lines enter, as well as the points where they run through or leave the collecting space, and the invention will now be exemplified by way of example

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an end connection for a superconducting three-phase coaxial cable described with such facilities. The drawing shows a schematic longitudinal section through this end connection. ·

The end connection shown is for a three-phase coaxial cable determines which has three tubular conductors 1, which are separated from each other and from an outer tubular cryogenic envelope 2 by evacuated annular spaces 3, are. The support (not shown) that holds the ladder φ and holds the shell in spatial relation to each other, can, consist of insulated spacers and / or lines through which a cryogenic medium can flow to the Head on about .; To hold 4.5 ° K.

Each ("conductor 1 can, for example, consist of a ring-shaped, gen body made of metal, which is not superconducting at operating temperature, only on one surface, or is coated on both its inner and outer surface with a thin layer of metal that is at operating temperature is superconducting; reference is made to a composite conductor according to the German patent application P 17 65 457.8. Each ring-shaped conductor body can w with a number of inner or outer leads for the. cryogenic medium, or it can. from internal and outer sleeves which are separated from one another by conductive spacers and between which an annular one Flow of: cryogenic medium flows; such coolant channels are indicated schematically at 4. The central E?, V.m 5 inside the inner tubular conductor is preferably evacuated and must be evacuated / grounded when connected to an evacuated one Space in the end connection. . -

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ORIGiNAL iM3Fu: iS0

Form line 12, through which a cryogenic medium through the end connection "through into the conductor · of the cable and ■ the conductor of the end connection is fed into it. Of the ' innermost spacer is connected to the supply line through a Device 3 connected-, · z-, B ·. a 'bellows device that the Line gives the opportunity to move lengthways relatively to move to the end connector. '· ■■ -....-. ■■ ■ ■ -

In the exemplary embodiment described here, this common supply line is provided with two heat ^shields: see: an outer heat shield 14 intended for higher temperatures, which extends only part of the way along the line within the end connection and a, inneren.Wärmeabschirmung 15 for intermediate temperature along the line almost as far as the · constriction in the "up" - the inner conductor at the point 9 between the Endanschlußlei- *:. tern iv and extends the conductors of the heat longitudinal shield .

Within the inner conductor, namely in the area of the "intermediate temperature zone - the longitudinal heat shield, the common feed line supplies a collecting space 16 inform -.-.-- a spherical stainless steel sleeve, and through the sleeve wall. Three glass distributor lines run radially after the-three conductors . the sleeves through which the glass pipes are passed through the sleeve wall, allowing, for example, by .Einbau of bellows 18, a relative movement in the radial direction to the collecting space between the pipes and the sleeve wall -. - · -. '

The line, which supplies the outer conductor, runs through corresponding recesses. 19 (in diameter larger than the line) in the intermediate and inner conductor, and the line that supplies the intermediate conductor runs through a similar recess 20 in the inner conductor. The line connected to each conductor delivers a

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cryogenic medium both after the cable conductor and after the corresponding end connection conductor, whereby a preset valve or valves 21 is or are provided, to ensure that the amount of medium flowing through the end connector is related to the Stands flowing through the cable ladder.

The distribution lines 17 extend into the common supply line and partially along the same on a straight or sinusoidal path to provide adequate protection against electrical breakdown or flashover between the conductors and the grounded plenum across the cryogenic medium flowing through the common Feed line passed through to ensure the conductors.

Me three coaxial conductors extend from the end connector through the vacuum seal at the high temperature end of the end connection into the atmosphere in the form of a coaxial connection and are each provided with an outlet line 22 for the cryogenic medium, which is made of insulating Material, such as glass, and is of such a length and shape that it corresponds to the potential gradient of the Conductor voltage at the point where it leaves the conductor, according to earth potential at the point where it enters the cooling device for the cryogenic medium. Cuffs, by means of which the lines are connected to the conductors are preferably provided with corona shields 23. the common feed line 12 remains axially arranged between these connection parts of the conductors and continues to extend beyond this.

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The cryogenic envelope 2 of the cable is by means of vacuum seals via an expansion bellows 24 to the low-voltage end a tubular insulator 25 made of glass or other suitable material, which is the outer shell for forms the end connection, the high voltage end of which holds the coaxial connection. Thermal and electrical shielding 26 or other means for shielding the end connection from radiation penetrating in the radial direction provided between the inner surface of this sheath and the outer surface of the outer conductor of the end terminal ..

In operational use, the spaces in the end connection between the coaxial conductors, between the outer conductor and the surrounding envelope and within the inner conductor.

The invention also relates to and relates to modifications of the embodiment outlined in the appended claim 1 especially to all features that are used individually - or in combination - in the entire description and Drawing are disclosed.

Expectations

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Claims (4)

Claims 1. End connection for a superconducting coaxial cable with a tubular insulating sheath facing the cryogenic sheath of the cable at one end and at the other End sealed against a coaxial connector is, as well as with a number of coaxial conductors, depending on one end to one of the conductive parts of the coaxial connector connected or formed in one piece with this and at the other end with one of the conductors of the cable in connection stand, characterized in that it is composed of insulating spacers and vacuum sealing means (11) between the conductive parts of the coaxial connector, means (24-) contained in the tubular insulating sheath of the end fitting and axial movement of the coaxial connection towards the end of the cable allows away from this in the event of a temperature change in the coaxial conductors of the end connection, and from a heat shield .in the connection between the coaxial conductors of the end connection and the cable conductors to inhibit transmission of heat through direct radiation in the longitudinal direction from the conductors of the end connection to the cable ladders. 909831/08 42 2. End connection according to claim 1, characterized in that that the heat shielding by the special shape of the coaxial conductors of the end connection (6,9) and / or the cable (1) is formed. 3. End connection according to claim 2, "characterized in that the heat shield by increasing the diameter the conductor is formed to a maximum and then reducing its diameter to each of the evacuated spaces between to give them a sinusoidal shape in such a way that no uninhibited α or uninterrupted straight line in the "annulus, with a its ends between the cable conductors and the other of its ends between the conductors of the end connector. 4. End connection according to claim 2, characterized in that the conductors of the end connection have a round cross-section and the longitudinal heat shield by increasing the Diameter of the conductor to a maximum and then reducing its diameter is formed to each of the evacuated To give spaces between them a sinusoidal shape in such a way that no unrestrained or uninterrupted right cylindrical or frustoconical surface in the annulus with one of its ends between the cable ladders and the other of them Ends between the conductors of the connection, lies, 5. End connection according to claim 3 or 4 »characterized in that the sinusoidal shape has an additional curved section which in turn is formed by increasing the diameter of each conductor to the diameter of the corresponding conductor of the connection. 6. End connection according to claim 1 to 5, characterized in that the innermost conductors of the cable and the end connection Both pipes are evacuated and that a longitudinal heat shield inside the pipe at the low-temperature . end of the end connection is formed by staggered impact bodies that protrude from the pipe wall. 909 831/0842 7. End connection according to claim 1 to 5, characterized in that the innermost conductor of the end connection is a is an evacuated tube, within which there is a common supply line (12) for supplying a cryogenic medium for cooling lines (4) is located inside the cable. 8. End connection according to claim 7, characterized in that the common feed line ends in a collecting space (16) which is arranged within the intermediate zone forming part of the longitudinal heat shield and forms part of the same. _Ä 9. End connection according to claim S, characterized in that each of the coaxial tubular conductors (6,9) is round Has cross-section and has a stump of a sphere "through planes on opposite sides of its center." is cut off that the common feed line (12) for cryogenic medium ends in a spherical collecting space (16). that each truncated ball is concentric to the spherical collecting space and that distribution lines made of insulating material extend radially from the plenum for supplying the cryogenic medium to the conductors. to. End termination according to claim 9, characterized m that a part flow of the cryogenic medium from the radial distribution lines along the cable and another portion back along the end fitting. 11. End connection according to claim 9, characterized in that separate radial lines for distributing the cryogenic Medium are provided in each of the cable conductors and in each of the end connection conductors. 909831/0842 4. Blank page