Design of SMES with reduced stray field

A design for an improved 50 kWh SMES arrangement was made concerning the 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 solenoid in such a way that the magnetic moments of all solenoids neutralize each other. Various methods to reduce the stray field were discussed and then the most promising solution-the one which produces the smallest magnetic stray field in combination with acceptable geometrical dimensions and conductor amounts-was analysed for further design. The coil calculation was based on a typical NbTi superconductor in order to match its critical data with the results of the optimized coil configuration.<>