Minimizing Voltage Deviations by Using Optimal Volt/VAr Curves Dynamic Control in Smart Inverters for Photovoltaic Installations

Abstract

This research paper proposes a new method to improve per unit voltage (V ${}_{\mathrm {pu}}$ ) control in electrical energy distribution systems (EEDS) through the appropriate injection or absorption of reactive power (Q) from photovoltaic smart inverters (PVSI) deployed within these systems. The improvement in the dynamics of the proposed Volt/VAr control curve (VVC) is based on determining per unit optimal voltage reference values at busbars hosting photovoltaic (PV) generators, by applying decoupled Proportional–Integral–Derivative (PID) controllers combined with an optimization procedure. These optimal voltage reference values are associated with optimal inverter reactive power values. The optimal VVC adjustment is performed while preserving the same slope as the conventional VVC. The proposed control method is validated through MATLAB simulations on the IEEE 13 bus test system, including three PV generators. The power flow analyses for this system are carried out in OpenDSS, and the interaction between MATLAB and OpenDSS is implemented via the OpenDSS COM interface. The results demonstrate the effectiveness of the proposed dynamic VVC control in reducing deviations of Vpu from 1 p.u., as well as decreasing the reactive power required from the PVSIs under peak generation conditions.