Impact of Larger Capacity of EV Batteries and Higher Output of Quick Chargers on Charging Peak Load

Abstract

Large-scale introduction of electric vehicles puts an electric load to the power system. Recently, the capacities of on-board batteries and the outputs of quick chargers have been increasing. Increase in battery capacity allows EV owners to charge more freely; however, the charging may concentrate at a certain time such as on Friday afternoon before a weekend, because EVs travel relatively long distance on weekend. Therefore, we evaluate the impact on the peak load, under large capacity batteries, high power quick chargers, and simultaneous charging. Charging threshold is defined as follows: when a state of charge (SOC) of an EV falls below the charging threshold, the EV goes to a quick charging station to charge. We set up cases that the charging thresholds are raised on Friday afternoon to prepare for EV use on a weekend.