Design and Comparison of a 1-MW/5-s HTS SMES With Toroidal and Solenoidal Geometry

The design of a high-temperature superconducting (HTS) Superconducting Magnetic Energy Storage (SMES) coil with solenoidal and toroidal geometry is carried out based on a commercially available second-generation HTS conductor. An SMES system of practical interest (1 MW/5 s) is considered. The comparison between ideal toroidal and solenoidal geometry is first discussed, and the criteria used for choosing the geometrical parameters of the coils' bore are explained. The design of the real coil is then carried out, and the final amount of conductor needed is compared. A preliminary comparison of the two coils in terms of ac loss during one charge and discharge cycle is also discussed.