A random selection method of starting time for electric vehicle is proposed. The control decision generator obtains electricity price and load information of current control area

divides valley period into several parts

and calculates the load capacity in each period considering the load curve. Charging pile calculates the probability distribution of the start charging moment corresponding to its user with different charging durations

and randomly determines the start charging moment based on generated probability distribution. In order to balance the utilization of valley power resources

the proposed method quantifies the load capacity of the grid as probability distribution during the valley period

and randomly generates the charging task according to the load capacity of each period. The charging task can be independently decided by the charging pile without complicated centralized communication control. The Monte Carlo simulation results show that the proposed strategy can effectively realize peak load shifting and stabilize the load fluctuation

and the system and user costs can also be reduced.