The SSD: a commercial application of magnetic energy storage

Abstract

Abstruct-A magnetic energy storage system (SSDTM) has been developed by Superconductivity, Inc. to provide power to industrial electric loads subjected to short term voltage disturbances. This paper provides an overview of the SSD system as presently installed at customer sites including magnet, cryostat, refrigeration and power conditioning equipment. Electric power interruptions are unpredictable in time but are typically of short duration. The SSD system provides rapid response backup power by means of a superconducting magnet connected to the load through a current to voltage converter and a dc to ac inverter. Power flows from the magnet to the load when the line voltage drops below a preset value. The magnet is designed with terminal characteristics matched to the inverter dc voltage, connected load and required carryover time. Cryogen inventory is maintained through use of a Collins cycle liquefier. All system components are designed for long term unattended operation and can be mounted in a semi-trailer. Remote monitoring provides information on system performance and status. A companion paper [l] reviews system operating experience.