Analytical distributed PV inverter reactive power support strategy for reduction of grid losses and voltage deviations

This paper deals with the reduction of power losses and voltage deviation in radial electrical power grids. To address these challenges, an innovative approach is proposed for controlling reactive power injections in electrical grids by distributed generators using analytical relations of reactive power to power loss and voltage deviation, with specific focus on photovoltaic (PV) generation. The proposed approach endeavors to achieve these objectives through analytical relations given by the deduced equations, thereby ensuring computational simplicity while optimizing the reduction of losses and voltage deviation. To this end, we deduce two closed-form equations for computing PV reactive power injections which reduce grid loss and voltage deviation. This paper also proposes an approach for efficiently switching between the Loss Reduction Algorithm (LRA) and the Voltage Regulation Algorithm (VRA), namely Combined Control Strategy (CCS). The method was tested via simulations on a radial network with a significant PV penetration over a 24-h time interval. The obtained results confirm the superior performance of the proposed equation-based approach compared to existing analytical methods in the literature. VRA achieved an RMSE of 1.7%, while CCS obtained 2.1%. LRA had the lowest losses, not considering voltage limits. With CCS, each bus in the electrical network violated the pre-established voltage levels (within ±3%) for only 0.72 min out of 1440 min in a day, a notably small value. Furthermore, the proposed approach significantly reduces the utilization of reactive power and active power supplied by the reference bus, while optimizing the balance between loss reduction and voltage regulation.