Optimization control scheme utilizing small-scale distributed generators and OLTC distribution transformers

The traditional policy of installing small-scale distributed generators (SSDGs) has focused on connection, rather than integration, with a fit-and-forget approach, based on the legacy of a passive distribution grid. Under this regime, the high penetration of SSDGs in distribution networks is expected to cause several issues related to power quality, efficiency and reliability. This paper proposes an optimization scheme to control both voltage magnitudes and voltage unbalances of LV distribution grids, utilizing on-load tap-changer (OLTC) distribution transformers, photovoltaic (PV) inverters, and batteries. Both the technical and cost models are taken into account for each of the aforementioned components, while the total cost function is constructed from the perspective of both distribution system operators' and domestic consumers' cost. The performance of the proposed approach is investigated on a typical rural Flemish feeder. We examine the violations of both voltage and voltage unbalance statutory limits, as well as the OLTC positions and the power utilization of both PV inverters and batteries.