Robust Volt/VAr Control With Photovoltaics

The new IEEE 1547-2018 standard includes dynamic Volt/VAr control for photovoltaic (PV) smart inverters. While recent research has addressed the problem of optimal inverter dispatch, the interaction between inverters and the classical Volt/VAr control (VVC) regulation system needs further study. This paper proposes an approach that builds on the classical VVC solution with PVs, by computing for each inverter a rule that modulates the smart inverter reactive power in function of its real power. Two approaches are presented for computing the inverter's reactive power equation slope: the first approach is based on the robust minimization of the absolute voltage magnitude deviation via a linear program, whereas the second approach yields closed-form solutions inspired from distributionally robust chance constraints. Numerical results are presented on weakly meshed distribution networks having up to 3146 nodes; they demonstrate that the voltage violations due to intermittent real power variations are significantly reduced by the decision rules as compared to maintaining the last computed VVC set-points, even when the inverters operate at constant power factor or with default Volt/VAr settings proposed in the literature; additionally, the reactive power decision rules maintain a network loss level that is close to the average from a centralized solution.