Reducing Neutral Current of a higher EV Penetrated Unbalanced Distribution Grid

Abstract

Electric vehicle (EV) penetration is rapidly increasing in the transport sector, which reduces carbon emissions and air pollutions. EVs are creating opportunities as well as challenges by integrating to electric power sectors. Due to the unbalance EV charging load in a three phase-four wire distribution grid, there exists neutral current as well as voltage unbalance at each node or measurement point of common coupling (PCC). Several researchers have assessed the impact of EV penetration on voltage and power quality. Moreover, a few research work has been done for reducing the neutral current in an unbalanced distribution grid with higher EV penetration till now. This paper proposes a method to reduce the neutral current at the supporting feeder, which is achieved by optimizing the voltage unbalance at the PCC. In this paper, this study will solve the neutral current overrating problem using Differential Evolution (DE) algorithm. Finally, the efficacy of the proposed method is evaluated by applying to a distribution grid. It is found that the proposed method can reduce the neutral current at the supporting feeder from 198.95 A to 19.45 A. The proposed method also reduces the neutral current at other nodes or PCCs up to 67.19%. The proposed method also reduces voltage imbalance and improve the voltage profile at each node.