A Day-Ahead Unit Commitment Model for Pumped-Storage Hydropower Plants Considering State-of-Charge Uncertainty and Reserve Activation Probabilities

The uncertainty in planned reserve activation leads to uncertainty in the state of charge (SoC) of pumped-storage hydropower plants (PSHPs). Investigating this uncertainty in the unit commitment (UC) problem is worthwhile. This paper presents a UC model that incorporates uncertainty in SoC caused by uncertainty in the probability of planned reserve activation for PSHPs. A SoC constraint boundary estimation model for PSHPs is developed considering the uncertainty in the probability of planned reserve activation across all preceding periods. The model also considers the uncertainties arising from load fluctuations and unit outages. Furthermore, a hybrid interval robust optimization approach is introduced, which simultaneously considers both pessimistic and optimistic scenarios to mitigate the bias in SoC boundary estimation caused by sample errors in the proposed model. Simulations on a modified IEEE 118-bus system verify the effectiveness of the proposed UC model.