Distribution grid impact of large number of EV charging with improved characterization

The impact of EV charging on distribution grids has been extensively investigated by assuming it as a constant active power load. The recent studies, however, contrarily show that the EV charging load is not only a mixture of constant power, constant current, and constant impedance loads but also a significant reactive power could be involved in it. Moreover, the active and reactive powers involved are heavily dependent on the state of charge (SOC) of the EV battery. Nevertheless, these aspects of the EV charging have not reflected in the models of the EV loads for the currently widely available impact analyses. Therefore, this paper proposes a novel method of the impact analysis by incorporating these unaccounted aspects of the EV charging in the EV load model. The proposed methodology has been tested on an IEEE 37 bus test system. The obtained results show that the impact of the EV charging for the proposed method could be considerably different to that for the conventional methods.