Evaluation of the adjustable-speed pumped hydro storage in systems with renewable resources

With the fast expansion of renewable resources in power systems, there is a growing interest in using pumped hydro storage (PHS) to facilitate the integration of high levels of renewable resources. In this paper, two different PHS technologies are studied, namely the traditional fixed-speed technology and the adjustable-speed technology. Mathematical models are developed for the two types of PHS technologies. A two-step approach is proposed to evaluate and compare the capabilities of the two PHS technologies to provide regulation reserves. The proposed approach represents the scheduling and the deployment of regulation reserves. The case study shows that the adjustable-speed PHS is more effective than the fixed-speed PHS in balancing renewable uncertainties in power systems.