Fig. 5
From: Revealing interactions between HVDC cross-area flows and frequency stability with explainable AI
Unscheduled flows and the frequency integral show different dependencies among the European grids. The model-independent scatter plots (top row) of unscheduled outflows and frequency integrals do not exhibit clear dependencies. Therefore we display SHAP dependency plots (bottom row), which depict the relationship extracted by the stability model thus isolating the effect of a single feature. The integral in the Nordic (a) and the GB area (b) show a positive relation to unscheduled flows, which corresponds to the effect of frequency control, while the CE unscheduled flows have a negative effect on the Nordic integral (c) thus showing a disturbance-like behavior. The scheduled flows (color code) demonstrate that Nordic-CE and GB-CE flows are mostly uni-directional, while CE-Nordic flows exhibit both directions (see main text for discussion)