Research On Electric Vehicles Orderly Charging And Discharging Considering Unit Commitment And Comprehensive Benefits

With the increasingly prominent problems of energy shortage and environmental pollution, the development of electric vehicle technology has been increa sing and the usage scale of which has been expanded rapidly. Nevertheless, charging and discharging disorderly to large numbers of electric vehicles, the load curve will suffer from great changes, which not only have adverse effects to the daily load forec asting and power dispatching, but also exert a great impact on the power plant unit operation cost and society comprehensive benefits. In order to solve these problems, a method of electric vehicles charging and discharging orderly considering both unit ru nning cost and society comprehensive benefits is presented in this paper.Firstly, on the basis of operation characteristics of different types of electric vehicles, the load models of charging and discharging of electric bus, electric private car and electric taxi are established, respectively. Then the charging number and charging power of each time interval are analyzed based on the calculation example.Then taking the insert of electric private car, which is most popular, to the grid into consideration only, we established the mathematical model considering unit commitment of electric vehicle charging and discharging orderly and solve it with genetic algorithm.Finally, in the case of the overall account of three types of electrical vehicles connected to the grid, taking both the reduction of unit carbon emission and peak load shifting of load curve brought by charging and discharging in order evenly, set the objective function considering both minimizing unit running cost and maximizing comprehensive benefits. And then let the number of electric vehicles charging and discharging in every time interval be the dispatching variables that can be optimized to build the mathematical model, and solve the model with mixed genetic particle algorithm. At last, a strategy of electric vehicle charging and discharging orderly can be obtained.The program algorithm is written by VC++ combined with MATLAB. Examples analyses prove the correctness and effectiveness of the algorithm. The example shows that unit running cost and carbon emission cost can be reduced markedly when certain amounts of electric vehicles charge and discharge in order, in addition, the peak load shifting of load curve can be effectively promoted.