Power System Ancillary Services Considering Electric Vehicles

Ancillary service is an important support means to guarantee the secure and stable operation of power system.With the large-scale access of distributed generations,the demand for ancillary service is further increased.At the same time,a large number of electric vehicles are connected to the grid,which puts forward new requirements to the operation control of the grid,and special features of electric vehicles make them promising candidates to provide ancillary services for the power system.The intelligent power distribution system makes it possible for electric vehicles to provide ancillary services,such as frequency regulation.The regulation bidding model proposed in this paper is based on the two-way information interaction among vehicle owners,aggregator,and grid operator.Firstly,the regulation potential of electric vehicle is determined according to the state parameters from vehicle owner.Based on the regulation potential,the aggregator offers its regulation capacity and bidding curves,and then bids in regulation market to meet the regulation demand.Finally,the aggregator controls the dispatched vehicles to provide regulation services.The simulation results show that electric vehicles can satisfy the regulation command signal to mitigate the fluctuation of distributed generations and loads,except several regulation-up signals during travel peak period.And the economic analysis indicates that electric vehicles can obtain economic profits by active provision of regulation services.To deal with a large number of electric vehicles connected to the grid,the coordinated charging control strategy for electric vehicles considering their spatial and temporal distribution is studied in this paper,making vehicle owners' travel needs met and charging cost minimized.Firstly,vehicle state parameters provided by the vehicle owner,combined with the historical travel information and regional geographic information,are used to predict the spatial and temporal distribution of electric vehicles in the next day.Then under the condition of time-of-use electricity price,the charging time of electric vehicles are solved by the heuristic algorithm to minimize the charging cost,and two kinds of charging control strategies are proposed.At last,the method of predicting the spatial and temporal distribution of electric vehicles' charging load is put forward.The simulation results show that the coordinated charging control can effectively reduce the charging cost and shift peak load to valley,but there is a big difference in the spatial and temporal distribution of charging load between different control strategies.