Exploiting inverter-interfaced DG for Voltage unbalance mitigation and ancillary services in distribution systems

The number of small scale distributed generators installed in the distribution network has dramatically grown, especially in Low Voltage networks. In these systems, the unevenly distributed power flow through the three-phases may even worsen due to single-phase connected DGs, causing voltage deviations and unbalance. In this paper, a control strategy for Low Voltage networks management is presented allowing the participation of DGs connected to the Low Voltage grid to the services required to manage the overall distribution system. The proposed control has been applied to a reference LV distribution network with the presence of inverter-interfaced DGs in a scenario with depleted power quality levels. The RMS dynamic simulations demonstrated that through the control strategy it is possible to mitigate the power quality issues within the Low Voltage networks and, at the same time, providing network services for the regulation of the upstream Medium Voltage network.