Dynamic regulation characteristics of pumped-storage plants with two generating units sharing common conduits and busbar for balancing variable renewable energy.

Abstract Pumped-storage plants (PSPs) are becoming increasingly important for balancing variable renewable energy (VRE) in power systems. A large portion of PSPs consist of multiple generating units (GUs) with shared water conduits and busbar. In this paper, an integrated transfer function (ITF) model for such PSPs in generation mode under primary frequency control (PFC) is proposed. Based on a real PSP in China, this ITF model is validated with both simulation results using the method of characteristics (MOC) as well as data from on-site measurements. For a series of governor parameter (K p and K i) settings under different governor control modes, stability limits expressed by gain and phase margins are evaluated and time domain simulations for balancing wind power variations are carried out to assess the quality of regulation. The results reveal that the dynamic regulation characteristics of the studied PSP system is clearly effected by the governor control mode. Besides, due to its complexity, a general range of the gain and phase margins is not viable for the studied PSP system under different governor control modes. Therefore, a thorough time domain sensitivity analysis using both step and realistic load disturbance as inputs is required for the studied PSPs for balancing VRE. Graphical abstract Image 1 Highlights • An integrated transfer function (ITF) is proposed for complex pumped-storage plants (PSPs). • The ITF is validated with method of characteristics and on-site experiments based on a real PSP. • Dynamic regulation characteristics of a complex PSP system is revealed. • Stability margins of the system under different operating conditions are evaluated. • Quality of regulation of the PSP for balancing wind power variations is studied. [ABSTRACT FROM AUTHOR]