A Practical PHEV Charging Policy to Improve Performance of Power Distribution Systems

Continuously dwindling fossil fuel reserves, high fuel costs, greenhouse gas (GHG) emissions and global warming has led to increased penetration of electric vehicles (EVs) in the transportation sector. However, EV charging increases the system load with high peak and off-peak demand ratio in the daily load profile, thereby causing increased system losses, poor bus voltages and power quality issues in power distribution systems. Adoption of a suitable electric vehicle charging policy can minimize this load profile distortion and reduce the maximum load. In this paper, a study on the charging effects of about 3000 electric vehicles in more than 800 residents is carried out on a 240-bus real distribution grid located in the Midwest U.S. Multiple case studies were carried out to investigate the profiles of the network demand and bus voltages without and with EV charging, vis-à-vis implementation of a practical PHEV charging policy. The results confirm the improvement of load and bus voltage profiles, thus validating the proposed EV charging guidelines.