Comparative analysis of effects of electric vehicle loads on distribution system voltages

A comparative analysis of effects of electric vehicle (EV) charging on primary and secondary circuit voltages is presented in this work. The EV charging effects are evaluated for increase in EV load penetration and EV load clustering. The voltage analysis is carried out using a 13.8-kV distribution feeder dominated by residential loads. The study reveals that EV charging affects the secondary voltages more significantly than the primary voltages. The percentage voltage drop recorded at the primary wire increases with the increase in EV load penetration. As expected due to the additional voltage drops in the secondary wires, the secondary circuit records even higher voltage drops. EV load clustering leads to an imbalance in the primary wire voltages. This causes significant voltage drops in a few secondary services while other record an increase in the voltage.