Design of a 150 kJ high-Tc SMES (HSMES) for a 20 kVA uninterruptible power supply system

A High temperature Superconducting Magnetic Energy Storage (HSMES) system has been designed and is being built by ACCEL Instruments GmbH in cooperation with the German companies AEG SVS GmbH, and EUS GmbH, and the utility company E.ON Bayern AG. The magnet is designed for an energy of 150 kJ. The superconducting coil is composed of twenty double pancakes wound of a high temperature superconductor tape with BSCCO-2223 filaments. The coil and the shield are conduction-cooled using a cryocooler; the cryostat is free of cryogens. The current leads are composed of a resistive part and a high temperature superconducting BSCCO-2212 MCP element. The HSMES will be integrated in a 20 kVA uninterruptible power supply (UPS) system coupled to the electrical grid for enhancing the power quality of a selected grid user. The design of the HSMES UPS system is described. A test module composed of two double pancakes wound from pre-series superconductor tapes was manufactured and tested at 77 K in order to check the magnet design and the coil manufacturing technique.