Abstract
Superconducting magnetic energy storage (SMES) is more useful than the other systems of electric energy storage because of larger stored energy and higher efficiency. Other systems are the battery, the flywheel, the pumped-storage power station. Some models of solenoid type SMES are designed in the United States and Japan. High magnetic field occurs in a large scale SMES in the living environment, which can cause error operations on computer displays, heart pacemakers and electronic equipment. The calculated results of the magnetic field of the solenoid type SMES is described in this study. The radius of the storage coil is 200 m, the height is 40 m and it is in the earth at 150 m under the surface of the earth. Its stored energy is 5 GWh and the maximum current is 666 kA. The maximum magnetic flux density on the surface of the earth is 0.34 T. Some suitable designs of magnetic shielding for reduction of the magnetic field in the living environment are discussed. When some superconducting shielding coils are over the main storage coil, the magnetic field reduction is greater than in the case of non-shielding coils. In addition, the electromagnetic force of the main coil is dispersed in the main coil and the shielding coils. The calculated results of the magnetic field are obtained using the finite element method. The toroidal type SMES is also studied. The leakage magnetic field is lower than the solenoid type SMES, but the electromagnetic force of the coil is very strong. Therefore a large scale model of a toroidal type SMES is unsuitable. The numerical analysis of magnetic field in the small scale toroidal type SMES is described by analytical calculation.
Get full access to this article
View all access options for this article.