Micro superconducting magnetic energy storage (SMES) system for protection of critical industrial and military loads

A 6 MJ, 750 kVA micro-SMES system has been designed to protect critical loads against voltage sags and interruptions, as well as to provide continuous power conditioning. Life-cycle costs have been minimized through the use of energy efficient refrigeration units. Maintenance is simplified through the use of line replaceable units. Availability is maximized through a design approach which allows the magnet to continue protecting the load even in the case of refrigeration degradation or total failure. Reliability is maximized by the use of proven commercial-off-the-shelf items. The system provides ride-through capability for /spl sim/9 seconds at a power level of 454 kW. The system comprises a niobium titanium superconducting magnet, permanent conduction cooled hybrid current leads, a low loss cryostat, a closed-loop refrigeration subsystem, an off-the-shelf uninterruptible power supply (UPS), a magnet interface unit to connect the magnet to the UPS and an off-the-shelf monitoring unit providing both local and remote monitoring capability of system parameters.