Abstract: Introducing large-scale electric vehicle （EV） into a power system would bring great impacts on power system’s planning, operation as well as electricity market development. This paper studied the unit commitment in power systems with considering large-scale EV, and proposed a unit commitment model with taking the needs of EV charging as constraints and the charging possibility of an EV in a certain period as the control variable that could be optimized. Taking the unit commitment of a 10-units 24-hours system as example, this paper compared the influences of three charging control strategies for different scale EVs on the optimization results of unit commitment in power system: disordered charging strategy, time of use （TOU） power price strategy and smart charging strategy. The results show that appropriate control strategy for EV charging can reduce the generation cost of power system.

Key words: electric vehicles, unit commitment, charging load, charging control strategy