Assessing the Operational Potential of EV Charger with Reactive Power Control for Improving Power Quality in Distribution System

Abstract

In this paper, the voltage control performance of several types of reactive power control by EV chargers is evaluated for the purpose of maintaining the proper voltage and improving the voltage unbalance ratio in the distribution system when EVs become more widespread. The popularity of electric vehicles (EVs) is on the rise due to environmental constraints such as reducing carbon dioxide emissions. On the other hand, there are concerns that EV charging will make it difficult to maintain proper voltage and worsen the voltage unbalance ratio in the distribution system. This is an issue that needs to be resolved as it will hinder the spread of EVs. However, it is difficult to counter the local voltage drop caused by EV charging with existing voltage control devices such as LRT and SVR. In this paper, we focus on the reactive power control function based on power factor adjustment in EV chargers, and evaluate the characteristics and voltage control performance of several reactive power control methods, from autonomous to centralized. The usefulness of each method was evaluated by numerical simulations using a model constructed based on the actual power distribution system in the Hokuriku area of Japan. From the results, it was confirmed that the reactive power control function by EV chargers contributes to the improvement of the EV installation availability ratio and the voltage unbalance ratio.