Design of a low-voltage mock-up of a new multi-terminal italian HVDC transmission system

High Voltage Direct Current (HVDC) transmission systems, especially in multi-terminal configuration, are expected to help accelerating the green energy transition in Europe, allowing the interconnections with remote renewable energy production sites. The SACOI2 HVDC system, operated by Terna S.p.A and Électricité de France S.A., is the only operating European multi-terminal transmission system and is currently undergoing a refurbishment phase with the aim to upgrade to the new SACOI3. Recent developments on HVDC circuit breakers (CBs) suggest further investigation in a possible adoption of half-bridge VSC (HB-VSC) converters. In this paper, an experimental low voltage prototype of the SACOI3 with scaled voltage and current values, being able to reproduce accurately the full-scale system, is designed and tested through electromagnetic transient analysis tools. The reduced scale mock-up examined in the paper will investigate the expected performances of a future SACOI3 link using HB-VSC converters, with experimentally measurable results.