Bi-level optimization of small pumped hydro systems for enhanced integration of renewable energy in hydro-electric coupling networks

Abstract

The integration of renewable energy into rural power grids poses significant challenges, such as line overloads and voltage violations, due to the mismatch between energy supply and increasing irrigation power demands. Small pumped hydro systems (PHS) provide a viable solution by dynamically addressing this mismatch through hydro-electric coupling. We introduce a bi-level iterative optimization approach to determine the optimal capacity and coupling point of PHS, while considering the uncertainties inherent in renewable energy sources. The upper level focuses on multi-objective voltage and loss sensitivity (MoVLS) to identify potential hydro-electric coupling points, which are subsequently evaluated at the lower level. The lower level utilizes robust information gap decision theory (IGDT) to optimize PHS capacity, aiming to minimize annual costs, with feedback provided to the upper level. Our results indicate a 3.285% reduction in annual costs compared to scenarios without a PHS system. Furthermore, our method achieves a 12.08% decrease in power loss and a 45.14% reduction in voltage fluctuation, surpassing single-objective siting strategies based solely on voltage and loss sensitivity.