A combined central-local volt/Var approach in distribution systems with high PV uptake

Massive integration of residential photovoltaic (PV) generation has caused overvoltage issues in distribution systems. In this paper, we propose a two-stage central-local solution using the unused capacity of the residential inverters. Unlike similar approaches, we propose to benefit from a wider range of information available at the local level, i.e., both voltage magnitude and real power injection. To achieve this, in the first stage, a central controller periodically takes measurement throughout the network to determine a scalar function mapping two local variables, namely real power injection/demand and voltage magnitude, to the reactive power of each inverter. The second stage is a local feedback controller that determines the inverter reactive power injection/absorption, using the provided functions and local measurements. The effectiveness of the proposed design is assessed on a real 30-bus LV feeder. The results are compared with the Volt/Var control suggested by IEEE standard 1547 and an optimal solution with complete information. Our simulations show that our design obtains near-optimal results, and keeps the voltages within the predefined limit in more scenarios than the IEEE standard 1547 while decreasing the required reactive power by 60%, and the real power loss by 3.3%.