Volt/Var Control Strategies in Distribution Feeders under DER-EV Penetration: A Bibliometric Review

Abstract

Volt/Var control is a fundamental strategy for maintaining power quality within predefined limits, reducing energy losses, and improving the operational efficiency of distribution feeders. However, the increasing penetration of distributed energy resources (DERs) and electric vehicles (EVs) has imposed significant challenges on traditional Volt/Var control schemes. In this regard, this work presents a PRISMA-aligned review of Volt/Var control strategies applied to distribution feeders with high DER/EV penetration. This review employs a six-stage workflow encompassing database searches Scopus and The Lens, corpus screening eligibility criteria and citation tracking, and evidence synthesize through temporal trends, VOSviewer-based keyword co-occurrence mapping, and a narrative assessment structured around seven research questions. The results reveal steady growth in the field since 2014, with a marked acceleration driven by rising DER penetration and new inverter grid-support requirements. Four main research fronts emerge: deterministic Volt/Var optimization using traditional devices; inverter-based reactive-power and power-quality control; PV-centric voltage regulation; and AI-enabled coordination strategies for EV charging management. In addition, the literature converges on hierarchical, multi-timescale control schemes that integrate OLTCs and capacitor banks with smart inverters, energy storage systems, and reactive-capable EV chargers, all supported by advanced computational and optimization tools.