A comprehensive optimization framework for EV-Renewable DG coordination

Abstract

This paper develops an optimization framework for coordinating electric vehicles (EVs) and renewable energy sources (RESs) in distribution systems. A bilateral contract between EV aggregators and renewable distributed generators (DGs) is first used to maximize revenues for these market participants by optimally controlling EV charging/discharging. The developed market-based EV control model is then implemented in a distribution system and evaluated for its potential adverse effects on the system operation. An optimal capacitor sizing and placement method is proposed to resolve the negative impacts of such control model. The proposed capacitor optimization method along with the developed EV control model provides an EV-RES coordination framework that simultaneously addresses both market and operational objectives. A real distribution network is used to test the EV-RES coordination method and evaluate its performance for different loading conditions using three-phase unbalanced load flow calculations. Simulation results validate the efficiency of the proposed method in not only providing cost savings for the system operation, but also in reducing the losses and voltage deviations that would be otherwise incurred due to uncoordinated EV scheduling. The proposed EV-RES coordination framework is demonstrated to ensure economic, safe and reliable operation of distribution systems in which EVs and renewable DGs synergize.