Nodal Sensitivity-Based Smart Inverter Control for Voltage Regulation in Distribution Feeder

Abstract

Overvoltage is one of the issues in distribution grids with high penetration of photovoltaics (PVs). Centralized or droop-based methods of active power curtailment (APC) and/or reactive power control of PVs are viable solutions to prevent overvoltage. This article proposes two distributed methods to control PV inverters, which are based on nodal sensitivities. Then, the performance of the proposed methods is compared with two commonly used control methods, i.e., a distributed method that follows IEEE-1547 but uses arbitrarily chosen droops and a centralized optimal power flow (OPF) based method. Performance is evaluated using a 730-node feeder with up to 100% penetration of inverters. Based on the case studies, the key findings are: first, local droop setting as per IEEE-1547, whether the droops are arbitrarily chosen or systematically calculated using sensitivities, can eliminate overvoltage if reactive power control and APC are coordinated, second, the proposed sensitivity-based approach yields the best voltage performance index computed based on voltage profile compared to the maximum allowed upper bound, and third, OPF-based method is desirable if communication infrastructure exists and minimum energy curtailment is sought.