DESIGN OF SMES WITH REDUCED STRAY FIELD

A design for an improved 50 kWh SMES arrangement was made concerning t he selection of an appropriate conductor, the determination of forces, efficient quench protection and mechanical strength calculation. The improvement relates to a drastic reduction of the magnetic stray field . This goal can be obtained by adding a second or even a third solenoi d in such a way that the magnetic moments of all solenoids neutralize each other. Various methods to reduce the stray field were discussed a nd then the most promising solution - the one which produces the small est magnetic stray field in combination with acceptable geometrical di mensions and conductor amounts - was regarded for further design, The coil calculation was based on a typical NbTi superconductor in order t o match its critical data with the results of the optimized coil confi guration.