The ever-growing number of converter-interfaced generators (CIGs) has been (and still is) changing modern power systems. The evolution has been fostered by two different, albeit complementary, processes: the widespread diffusion of generators driven by renewable sources, such as solar radiation and wind, and the increased awareness of final users on energy efficiency.

From the grid’s perspective, the replacement of conventional generation plants by CIGs bears more significance than expected. CIGs should replace the inertia they are contributing to phase out. In addition to this, when conventional generators become too few, CIGs should also set and maintain the frequency for the whole power system. The viability of a converter-dominated power system has been recently assessed, concluding that a scenario of 100% of converter-interfaced generators may be feasible.

However, all existing studies have thoroughly analysed the stability of the control systems of the converter controls, supposing the grid to be almost ideal (modelled as three voltage source generators connected to the converter by equivalent impedances) or made up of a limited number of nodes. These simplifying assumptions were clearly well justified by the aim of the investigations. Little has been said in case of the concurrent presence of multiple CIGs connected to a complex grid. When such grids are studied, usually power converters are replaced by their average models. This reduces the computational burden but reduces the resolution of the results as some dynamic behaviours may go undetected.

SCooPS (Stability of converter-dominated power systems) intends to fill this gap. In particular, the objectives are:

• analyse the stability of the grid when multiple CIGs are connected to a complex grid;
• analyse how the interactions among the different controllers of CIGs (as they may be grid-forming, grid-feeding, or grid-supporting) and with the other components of the power system may affect the overall stability;
• provide stabilizing control solutions able to solve eventual stability issues resulted from the analysis.

The stability analysis and the control design will be assessed by hardware-in-the-loop simulations, where real prototype versions of CIGs will be realized and included in high detailed simulations tests.

The research will be conducted in collaboration with the units from the University of Genova, directed by Prof. Federico Silvestro, and from the University Campus Bio-Medico of Rome, directed by Dr. Francesco Conte.