Coordinated charging strategy for PEVs charging stations

Under the constraints of distribution transformer capacity and satisfying customers charging needs, a two-stage plug-in electric vehicles (PEVs) coordinated charging optimization formulation for charging stations is proposed. In the first stage optimization, the economic profits of the charging stations are maximized and customers´ charging demands are satisfied as much as possible. Furthermore, the peak load of the distribution transformer is minimized in the second stage optimization under the constraints based on the results obtained in the first stage optimization. Monte Carlo Simulation method is utilized to sample the charging behaviors of customers. The profits of charging stations and loading of distribution transformer are simulated under coordinated charging strategy with peak load control, coordinated charging strategy without peak load control and uncoordinated charging scenarios correspondingly. The simulation results in Beijing and Shanghai in China indicate that by responding Time of Use (TOU) electricity rates, the profits of the charging stations can be significantly improved without sacrificing the customers´ service quality under coordinated charging. Furthermore, the coordinated charging strategy with peak load control which goes through the second stage optimization effectively lowers the peak load of distribution transformer and prevents the possible charging concentration during the late night.