THE ADVANTAGES OF USING HIGH-TEMPERATURE SUPERCONDUCTORS IN HIGH-DUTY-CYCLE APPLICATIONS OF SMES

Superconducting magnetic energy storage (SMES) has been preoposed for use in applications with high-duty-cycle or discharge/charge cycling r ate. Such applications include transit system electric support and fre quency stablization of transmission lines. When cycled frequently, the thermal load to the cooling system is dominted by eddy current or ac losses. In systems with small energy storage capacity, the refrigerati on system cost associated with sc losses can dominate the total system cost if the coil uses conventional superconductor and liquid helium c ooling. If high temperature superconductors operating at liquid nitrog en temperature could be used then significant savings in refrigeration cost and hence, system cost, are possible. The HTS conductor does req uire a twisted configuration to realize these savings. Analysis and re sults for SMES systems ranging in size from 1 MJ/1 MW to 10 MJ/10 MW a nd operating at up to 1 Hz are presented.