Impacts of electric vehicles on the transient voltage stability of distribution network and the study of improvement measures

Electric vehicles connected directly to the distribution network are expected to increase the base electric loads and reduce the stability of a power system. Meanwhile, equipped with bidirectional battery chargers, electric vehicles can work in V2G mode, as spinning reserve, and enhance grid stability. This paper discusses the charger technologies, requirements and proposes transient voltage stability margin index considering the impacts of dynamic loads on the transient voltage stability grid. Based on the index, the paper evaluates and compares the impacts of electric vehicles charging loads, static loads and combined loads on the transient voltage stability of distribution network and proposes the improvement of considering the V2G mode for the transient voltage instability situation of electric vehicle charging. The model of bidirectional battery chargers and IEEE16 bus test systems are performed by MATLAB & SimPowerSystems, and the availability of the index is confirmed.