Reactive Power Management in Low Voltage Distribution Networks Using Capability and Oversizing of PV Smart Inverters

Since integration of solar photovoltaic (PV) sources into the power grid is increasing rapidly in recent years, the capability of photovoltaic source inverters can be an opportunity to improve the technical and economic indicators via reactive power management in low voltage distribution networks grids. This work proposes an optimal planning model to improve the voltage deviation index and increase the revenue sale electricity with the capability of PV inverters and fixed capacitors. In this regard, the optimal capacity of the PV inverter is determined simultaneously with the location and number of fixed capacitors to minimize investment (for PV inverter, fixed capacitor, operating cost) and maximize electricity sales revenue. For this purpose, an innovative model is presented that is able to calculate the annual technical-economic evaluation. To make the costs for investment, operation and maintenance of compensating devices more realistic, the lifespan and additional cost of inverter oversizing in the objective function are modelled. In this article, load flow equations along with technical constraints are integrated into a mixed-integer second-order conic programming model. Two real grids were simulated using MATLAB software in order to show the effectiveness of the proposed model. The comparison of the proposed RPM method with conventional methods confirmed considerable reduction of investment and energy losses in the low voltage distribution networks grids.