Voltage regulation in unbalanced power distribution systems with residential PV systems

Increased integration of rooftop photovoltaic (PV) power generation in a low-voltage power distribution system poses significant challenges due to the severity of voltage unbalance problems and complexities in regulating the voltage. Conventional regulation methods are insufficient to address these challenges due to their inability to deal with the voltage unbalance. This paper proposes an advanced supervisory control methodology, with the reactive power control and voltage regulation at residential PV inverters, as an effective means of addressing unbalanced voltages in a power distribution system. The uniqueness of the approach is that it simultaneously controls voltage magnitude and voltage unbalance at affected nodes by precise dispatching of reactive power. Several cases were studied by simulating realistic operating conditions on the unbalanced IEEE 37-node test feeder, and results suggest that the proposed approach can manage the voltage magnitude at nodes within voltage unbalance thresholds. Further cases suggest that the application of the proposed methodology could also reduce the operational stress of residential PV inverters significantly, facilitating distribution system with an increased capacity of PV power generation.