Impact of High Penetration of EV Charging on Harmonics in Distribution Networks

Electric vehicles (EV) are becoming the most preferred and rapidly growing mode of transportation all around the world. Development of battery technologies and attention on residential scale renewable energy based distribution generation has accelerated the growth of the EV market. Rechargeable batteries are the most common type of energy storage in commercial EVs. A regulated DC current shall be supplied to EV charging and the charging currents are higher compared to conventional loads. Power electronic converters are essential for the AC DC conversion thus a distorted current is fed to the nonlinear load. This will give rise to power quality issues such as voltage unbalance, voltage fluctuations and harmonics in the distribution systems. It is important to study and quantify the power quality impacts to make sure the healthy operation of the distribution system. A commonly available EV charger was modelled in Matlab to study EV chargers in this research and a comprehensive harmonic analysis was carried out in a LV distribution feeder. The research studies impact to the feeder with different EV penetration levels as well as EV charging with different load levels.