Mitigating Voltage Unbalance Using Distributed Solar Photovoltaic Inverters

Maintaining balanced voltages across distribution networks is becoming more challenging with increasing deployment of single-phase distributed generation and larger single-phase loads. The paper develops a reactive power compensation strategy that uses distributed solar photovoltaic (PV) inverters to mitigate such voltage unbalance. The proposed strategy takes advantage of Steinmetz design and is implemented via both decentralized and distributed control. The latter coordinates PV inverters through a communication network. We demonstrate the performance of the controllers on the IEEE 13-node feeder and a much larger taxonomy feeder (617 nodes and 1196 triplex nodes), and consider different connections of loads and PV systems. Simulation results demonstrate the trade-offs between the controllers. It is observed that the distributed controller achieves greater voltage unbalance reduction than the decentralized controller, but requires communication infrastructure.