The largest Italian SMES

The industrial prototype of a superconducting magnetic energy storage (SMES), sized to deliver 1 MW for 1 s, was designed and constructed as the result of a research project, partly funded by the Italian Ministry of Education, University and Research. After successfully undergoing factory tests, the SMES was installed at the Elettra Synchrotron Light facility in Trieste-I and is there under commissioning and testing as protecting device from temporary voltage dips and interruptions, the most frequent grid malfunctions causing faults of the beam magnetic confinement system. The innovative part of the prototype, which also includes several sophisticated power electronics items, is a 2.6 MJ stored energy magnet, wound with a new low-losses Nb Ti cable, cooled by liquid helium at 4.2 K and adopting an electric insulation design solution to withstand 8 kV and obtain very close contact between coolant and coil. New design hybrid current leads, made of a resistive copper stage and a high temperature superconducting one, cooperate together with a set of three cryocoolers and a multi-shield cryostat to keep the helium loss amount negligible. Electrical insulation of the most critical components and the quench detection system is extremely accurate, because the voltage at coil-ends rises up to 2.500 V. The experimental results obtained at Elettra during the beginning of the SMES commissioning phase are presented.