Impact of Quaternary Pumped Storage Hydropower on Frequency Response of U.S. Western Interconnection with High Renewable Penetrations

As renewable penetrations increase in the United States, maintaining the stability and reliability of low-inertia power grids by providing sufficient frequency control capabilities becomes a challenge. Advanced pumped storage hydropower (A-PSH) technologies will be expected to play an essential role in the future grid to provide energy and ancillary services. This paper studies the impact of using quaternary pumped storage hydropower (Q-PSH) as a newly proposed A-PSH technology to provide primary frequency response. To quantify the impact of Q-PSH on the frequency response of the U.S. Western Interconnection, a user-defined dynamic model of Q-PSH is developed in the GE Positive Sequence Load Flow (PSLF) software and is implemented in a set of detailed U.S. Western Electricity Coordinating Council planning cases, in which renewable penetration levels are 20%, 40%, 60%, and 80%. Simulation results show that Q-PSH can help improve the frequency nadir and the settling frequency compared to conventional PSH.