Performance of df/dt-based Inertia Control during Emergency Islanding

In power systems with high penetration rates of inverter-based generation, the system inertia constant decreases. This causes an increased rate of change of frequency (ROCOF), e.g. after plant outages or fault-induced system splits, and may lead to frequency instability. Synthetic inertia schemes have been proposed to provide inertia with power electronic converters, especially in wind turbines due to the available energy storage. This paper focuses on the system split scenario, i.e. where a grid area is suddenly isolated from the bulk power system. This scenario is investigated for three cases: i.) a conventional synchronous generation mix, ii.) a high share of power converters without synthetic inertia, and iii.) a high share of power converters with df/dt inertia emulation. Potential violations of frequency and voltage limits are identified for each scenario, and the robustness is compared among the generation configurations. Load shedding and asynchronous motor loads influence the system behavior significantly and are therefore modeled explicitly.