Improved Voltage Control Strategy for Photovoltaic Grid-Connected System Based on DoubleLayer Coordination Control

An improved automatic voltage coordination control strategy(AVCCS) based on automatic voltage control(AVC) and battery energy storage control(BESC) is proposed for photovoltaic grid-connected system(PVGS) to mitigate the voltage fluctuations caused by environmental disturbances.Only AVC is used when small environmental disturbances happen,while BESC is incorporated with AVC to restrain the voltage fluctuations when large disturbances happen.An adjustable parameter determining the allowed amplitudes of voltage fluctuations is introduced to realize the above switching process.A benchmark low voltage distribution system including PVGS is established by using the commercial software DIg SILENT.Simulation results show that the voltage under AVCCS satisfies the IEEE Standard 1547,and the installed battery capacity is also reduced.Meanwhile,the battery’s service life is extended by avoiding frequent charges/discharges in the control process.