Local Smart Inverter Control to Mitigate the Effects of Photovoltaic (PV) Generation Variability

The rapidly transforming electric power distribution system due to the integration of distributed energy resources (DERs) specifically roof-top photovoltaic (PV) generation may lead to significant operational challenges. In this paper, we address the challenges related to variable power generation profile from PV resources leading to voltage fluctuations at the secondary feeder level. The objective is to develop local smart inverter control methods to reduce the voltage fluctuations at distribution buses using reactive power support. Towards this goal, an approach based on the power flow measurements of the lines connected to the PV generation buses and the local PV generation measurements is proposed to obtain the required reactive power support to mitigate voltage fluctuations. The proposed method is validated using two three-phase unbalanced test systems: IEEE-123 bus and the modified R3-12.47-2 taxonomy feeder with 329-buses. It is shown that the proposed local control approach is effective in mitigating voltage violations resulting from large changes in active power injections of the PV generators and in reducing overall voltage fluctuations due to PV generation variability. Further, it is validated that the proposed local control approach results in a better performance with regard to decreasing the voltage fluctuations compared to a standard Thevenin impedance-based method.