Peak-demand management for improving undervoltages in distribution systems with electric vehicle connection by stationary battery

Nowadays, electric vehicles are promoted in many countries. Electric power systems could be developed to mitigate ineffective electricity such as undervoltages, harmonics, etc. This paper focused on Lithium-ion based batteries which reduces those problems by finding the size to correlate with the behaviors of the EVs connected to the residential feeders in distribution systems modeled by IEEE 34-node test feeder. Energy storage systems were applied to control and analyze the profiles of the systems. 40%, 45%, and 50% EV penetration were assumed in the study. It was found that 1250 kWh battery capacity and 250 kW discharging power in the peak duration could improve undervoltages by 3.61%, 3.72%, and 3.82% respectively. This battery specification could shave the peak demand by 3.29%, 3.26%, and 3.24% in the three levels respectively. However, this system with small battery size can only be done by reducing the voltage drop and a little power reduction. Some devices or more batteries might be applied into many locations to help more effective peak-shaving.