The variable speed and constant frequency pumped storage hydropower (PSH) unit can strongly support the complementation and joint power supply of cascaded hydropower and photovoltaic (PV) plants. Its fast response capability has provided a feasible solution for the rapid power and voltage regulation caused by real-time fluctuations of PV systems. However

currently there is a lack of research on precise evaluation on regulation capability and regulating capacity configuration for PSH to restrain the real-time fluctuations. In this paper

a cascaded hydro-PV-PSH complementary joint power system (CHPP) is studied

and a "rule-based" method for regulating capacity determination is proposed. A combined statistical technique is introduced to analyze the initial estimated regulating capacity of PSH. A continuous cyclic revision method is adopted to renew the ideal PV curve by repeatedly using the main operating constraints until an optimal regulating capacity of PSH matching the PV generation scale is achieved. The results of the case study verified the feasibility and effectiveness of PSH for restraining the fast fluctuations of PV systems in real-time

and the configuration between PV and PSH regulating capacity is obtained with real-time application requirements. Finally

analyses including weather conditions

curtailed energy and electricity shortage

the sensitivity analysis

and state transition frequency are presented to demonstrate the robustness of this study.