UA-CrossBorder-Flows: an open hourly dataset and day-ahead export-forecast pipeline for the cross-border electricity flows of the IPS of Ukraine (to PL, SK, RO, MD)

An open hourly dataset of the real measured physical electricity export flows from the Integrated Power System (IPS) of Ukraine to its neighbours Poland, Slovakia, Romania and Moldova, taken from the ENTSO-E Transparency Platform (CC-BY 4.0), enriched with the Ukrainian day-ahead price (ENTSO-E) and Open-Meteo temperature. The task is day-ahead forecasting of the total cross-border export from causal features (export history ≥ 24 h, calendar, price, weather). Two aligned versions: base_v1 (calendar) and improved_v2 (+ flow lags + price + climate). Honest result: Ukrainian export is intrinsically volatile (commercial dispatch + war), so day-ahead predictability is low (best R² ≈ 0.12), yet the added flow-history and price features cut MAE ≈28% (255→184 MW) and RMSE 327→239 MW. 29,762 hourly rows (2022–2025). This real interconnection-state series is also a building block for digital-twin monitoring of the Ukrainian power system (the author's ITMM-2025 thesis).