Integrated control of photovoltaic-energy storage system for power oscillation damping enhancement

Due to the lack of damping regulator, the power oscillation in the power system with high penetration of photovoltaic-energy storage devices will threaten the dynamic stability of the system. Based on the analysis of the operation characteristics and control scheme of the photovoltaic-energy storage system, the relationships between the active and reactive power regulation and the power oscillation damping are discussed, and the novel additional active and reactive power modulations are proposed respectively for improved system damping. The proposed strategy switches the control mode of the PV grid connected inverter and the battery energy storage during power oscillations according to the frequency deviation and State-of-Charge(SOC) of Battery which avoids the deep charge and discharge of energy storage device. Finally, a typical power system with photovoltaic penetration of around 30% is used to validate the proposed control strategies. Simulation results show that the power oscillations can be significantly damped with the power regulations of photovoltaic-energy storage system.