Development of Superconducting Devices for Power Grids in Italy: Update About the SFCL Project and Launching of the Research Activity on HTS Cables

Abstract

In the framework of the development of High Temperature Superconducting (HTS)-based solutions for modern power grids, Ricerca sul Sistema Energetico - RSE S.p.A. has gained a significant experience in design, testing, and installation of superconducting fault current limiters (SFCLs). After having successfully demonstrated the techno-economic feasibility of the first Italian three-phase BSCCO-based SFCL (9 kV/3.4 MVA) inside the distribution grid of A2A Reti Elettriche S.p.A. in the Milano area, RSE has initiated the development of a new upgraded three-phase SFCL, whose rated power has been enhanced in order to meet the utility's needs. Unlike the first prototype, the new SFCL device (9 kV/15.6 MVA) is YBCO-based: this choice allows reducing the needed tape length and cooling power, saving at the same time a significant amount of operational costs. The first phase was already assembled and tested in 2015, whereas the second phase was tested in February 2016. This paper will show the last outcomes from characterizations and short-circuit tests. Along with the SFCL project, RSE has also been focusing on superconducting cables and, in the framework of the European Project Best Paths, it has been involved in DEMO5, that is dedicated to the development of a HTS DC cable in MgB2 (10 kA/3.2GW). Taking the cue from the DEMO5 requirements, RSE has initiated a parallel research activity that is focused on studying the thermo-fluid dynamic behavior of cryogenic coolants flowing in forced convection regime inside the flexible cryostat. This paper will present the first simulation results and will give some anticipation on next steps.