Superconductive device without an external shunt system, in particular with a ring shape

Abstract

A superconducting device ( 1; 1 a , 1 b ), having a coated conductor ( 2 ) with a substrate ( 3 ) and a quenchable superconducting film ( 4 ), wherein the coated conductor ( 2 ) has a width W and a length L, is characterized in that 0.5≦L/W≦10, in particular 0.5≦L/W≦8, and that the coated conductor ( 2 ) has an engineering resistivity ρ eng shunting the superconducting film ( 4 ) in a quenched state, with ρ eng >2.5Ω, wherein R IntShunt =ρ eng *L/W, with R IntShunt : internal shunt resistance of the coated conductor ( 2 ). The risk of a burnout of a superconducting device in case of a quench in its superconducting film is thereby further reduced.

I claim: 
     
         1 . A superconducting device having a coated conductor, the coated conductor comprising:
 a substrate; and   a quenchable superconducting film, wherein said coated conductor has a width W and a length L, with 0.5≦L/W≦10 or 0.5≦L/W≦8, the coated conductor having an engineering resistivity ρ eng  shunting said superconducting film in a quenched state thereof, wherein ρ eng >2.5Ω, with R IntShunt =ρ eng *L/W and R IntShunt : an internal shunt resistance of the coated conductor.   
     
     
         2 . The superconducting device of  claim 1 , wherein the substrate is a metallic substrate electrically insulated from said superconducting film, a dielectric substrate, a thin metallic substrate or a thin metallic substrate having a thickness T≦100 μm. 
     
     
         3 . The superconducting device of  claim 1 , wherein W≧12 mm or W≧40 mm. 
     
     
         4 . The superconducting device of  claim 1 , wherein W≧50 mm or W≧100 mm. 
     
     
         5 . The superconducting device of  claim 1 , wherein L≧10 cm or L≧36 cm. 
     
     
         6 . The superconducting device of  claim 1 , wherein L≧50 cm or L≧100 cm. 
     
     
         7 . The superconducting device of  claim 1 , wherein said superconducting film comprises YBCO material. 
     
     
         8 . A superconducting device having a coated conductor, the coated conductor comprising:
 a substrate; and   a quenchable superconducting film, the coated conductor having a width W and a length L, wherein a length of a primary normal zone generated by a quench in said quenchable superconducting film corresponds to said length L of the coated conductor or to a substantial part of said length L.   
     
     
         9 . The superconductive device of  claim 8 , wherein said coated conductor has a width W and a length L, with 0.5≦L/W≦10 or 0.5≦L/W≦8, the coated conductor having an engineering resistivity ρ eng  shunting said superconducting film in a quenched state thereof, wherein ρ eng >2.5Ω, with R IntShunt =ρ eng *L/W and R IntShunt : an internal shunt resistance of the coated conductor. 
     
     
         10 . The superconducting device of  claim 1 , wherein the coated conductor forms a closed loop. 
     
     
         11 . The superconducting device of  claim 8 , wherein the coated conductor forms a closed loop. 
     
     
         12 . The superconducting device of  claim 10 , wherein, in an end region of the coated conductor, a part of said substrate is removed and superconducting film parts at said end region and at a further end region of the coated conductor are jointed with each other or a mechanical support structure is provided on top of said superconducting film at said end region near said removed part. 
     
     
         13 . The superconducting device of  claim 10 , wherein said substrate of the coated conductor is of a ring type or circular ring type. 
     
     
         14 . The superconducting device of  claim 10 , wherein two end regions of the coated conductor are bent inward or outward and superconductor film parts are jointed with each other at end regions thereof. 
     
     
         15 . A superconducting assembly comprising a plurality of coaxially arranged superconducting devices of  claim 10 , placed one within an other. 
     
     
         16 . A fault current limiter comprising the superconducting device of  claim 1 . 
     
     
         17 . A fault current limiter comprising the superconducting device of  claim 8 . 
     
     
         18 . The fault current limiter of  claim 16 , wherein the fault current limiter is of an AC type with a primary coil for carrying a current to be limited and a secondary coil to be coupled to said primary coil via a common magnetic flux, wherein the superconducting device is included in said secondary coil. 
     
     
         19 . The fault current limiter of  claim 18 , wherein said secondary coil comprises a plurality of sub-coils which are realized as superconducting devices, wherein said coated conductor forms a closed loop, the superconducting devices being placed next to each other and within said primary coil.