Actively shielded transportable SMES-systems

Previous investigations on active shielding of SMES systems have proved to be successful in reducing the stray field. It was shown that the stray field of a single solenoidal SMES can be diminished by adding shielding solenoids under the condition that the sum of the magnetic dipole moments of all coils equals zero. Computations revealed diameters of those SMES arrangements in the range of several meters for a given SMES capacity of 50 kWh, which may be appropriate for grid stabilization. This restricts coil transportation severely. The present paper mainly concentrates on this problem and deals with SMES systems with outer diameters not more than 2.3 m. This provides easy transportation either on rail or on road with the crucial benefit that only final assembly of prefabricated modules has to be done on the prospective site. An arrangement of such an actively shielded transportable SMES is optimized for a minimum of length and for a minimum of superconductor. Furthermore its performance in reducing the stray field is compared to previous SMES systems