Abstract
To scale up the capacity of a SMES for a practical application, it should be necessary to adopt a high voltage system, a large current system or a module type system. The first system is difficult because of the very low withstanding voltage of a supercon-ducting coil and second one also leads difficulties such as multiple connections of many units of convertors at dc side and large current conductors of superconducting coil. The third system which is composed of some numbers of modules with small scale convertor units and element coils might be a solution of above difficulties.
In this paper, based on conceptual designs of the SMES system with 350kWh and 550MVA, features of the module type SMES are discussed by comparison between systems with different numbers of modules. Discussions are made on technical points as well as on economical points. The result elucidates features of this type SMES. Then to confirm operations of the module type SMES, the experimental system of two module units with a GTO convertor and two superconducting coils is constructed. Experimental results show that the module type system can be operated without any troubles in case of normal operation and also in case of energy transfer between two modules.
