Active-reactive optimal power flow for low-voltage networks with photovoltaic distributed generation

Photovoltaic systems (PVSs) are more and more installed in low voltage distribution networks (LV-DNs) for absorbing solar energy. Features of such networks need to be analyzed for a reliable and optimal design as well as operation. In this study, we introduce a mathematical model derived from a combined active-reactive optimal power flow (A-R-OPF) for LV-DNs by taking into account the reactive power capability of photovoltaic distributed generation (DG). Using multiple performance criteria, it is possible to analyze the impact of controlling reactive power sources LV-DNs. A real 29-bus LV-DN is employed to demonstrate the effectiveness of the proposed method, based on which interesting results have been achieved. For instance, up to 25% of annual energy costs can be saved and there is no need in this case study to use battery storage systems (BSSs) in LV-DNs for accommodating spilled PV energy.