DC Grids for Supporting AC Power System during Failure Events: Experimental Testing of a Urban Case Study

AC power systems and their devices can be subjected to different failure events due to thermal, environmental, and aging phenomena. In this context, DC grids intervention could mitigate customers black-out by adequately controlling their internal resources (renewable generators and storage systems). In this paper, failure events concerning HV/MV transformer are considered. Possible actions to support the AC grid to avoid interruption in load areas are analyzed and experimentally validated. Tests campaigns are carried out taking advantage of a research nanogrid infrastructure available at ENEA Centre of Portici. It consists of indoor equipment able to emulate actual generation, load and storage systems and outdoor facilities. In addition, the availability of Hardware In the Loop system allows to reproduce TSO and DSO grids connection. The emulation of fault conditions is carried out to verify DC grids strategies correctness. Finally, Key Performance Indices (Interruption Time and Not Supplied Energy amount) are obtained for an urban case study.