Coordinated Control Strategy for Photovoltaic Power Plant with Battery Energy Storage System

An increasing penetration of photovoltaic (PV) generation with the traditional inverter-based characteristics threatens the security and stability of power systems. As a result, different grid codes have been proposed to confine both the steady-state and dynamic behaviors of PV power stations. Some of these requirements can be easily met, while some need special design for the control strategy. PV power stations can control their ramp rates of output power and provide frequency support as well as virtual inertia to the power system by properly utilizing the Limited Power Point Tracking (LPPT) control. However, the frequency regulation and virtual inertia control fulfilled by LPPT requires PV power stations to operate at derating mode, resulting in large amount of solar energy curtailment. Thus, the installation of battery energy storage system (BESS) is extensively used for providing virtual inertia support. This paper proposed a coordinated dynamic control scheme for a PV power station equipped with the BESS system, aiming to provide frequency support and virtual inertia to the power system during disturbance. The simulation test and theoretical analysis for the impact of the developed coordinated dynamic control strategy on the power system are carried out in several case studies.