Unified Power Quality Evaluation of Charging Electrical Vehicles on Electrical Grid

Abstract

Electrical vehicles (EVs) are marking a revolution in the world because of its environmental and economic benefits. However, charging EVs affects the energy quality of the electrical network. Therefore, this paper adopts to analyze the power quality (PQ) impact of EVs charging from the electrical grid. PQ is analyzed based on five quality factors which are “harmonics of voltage and current, voltage sag, voltage unbalance, and frequency deviation”. The effect of charging EV depends on the number of charging vehicles from the same location at the same time. Therefore, this work introduces two charging locations; at charging stations that have many EVs, and individual charging at the home that has one vehicle. Although the PQ effect of EV charging at home is less than at the charging station, at home the negative PQ impact is spread along the street. While at the station, the PQ impact is concentrated in one place. To determine the impact range of electric vehicle charging on the grid quality, it is preferable to have one indicator to determine this value. Therefore, this paper presents a unified power quality index (UPQI) for estimating PQ which is based on the five proposed quality factors using an artificial neural network (ANN).