Impact of V2G operation of electric vehicle chargers on distribution grid during voltage dips

Abstract

© 2019 IEEE. In next decades rapid rise of electric vehicle (EV) number is expected. Bi-directional EV chargers operating in grid-to-vehicle (G2V) and vehicle-to-grid (V2G) modes are envisioned for energy transfer. In case of clustering large number of EVs at a distribution grid bus, operation in V2G mode may be used for grid support during faults according to the low-voltage ride-through (LVRT) requirements. Faults in the distribution grid may cause fast variation of voltages, i.e. voltage dips and bursts of harmonics. Research emphasizing the transient and dynamic analysis is presented. Possibility of voltage improvement during voltage dips is tested with EV chargers operating in V2G mode. Detail simulations on IEEE 13-bus test grid, with 3 MW of added distributed generation (wind and solar) and 0.48 MW of added EV chargers cluster are used. Voltage signals at the connection point of the EV chargers produced by six characteristic types of faults, that occurred at two different locations in the distribution test grid and causing various voltage dips are recorded and analysed. It is shown that significant reduction of voltage harmonics and improvement in voltages may be reached.