Study On Dynamic Economic Dispatch Of Large-Scale Electric Vehicles Integrated Power Systems

To deal with the increasingly serious energy crisis and environmental pollution, electric vehicles (EVs) as a pollution-free and zero emissions transport tool has been popularized and widely applied in the world. Large-scale EVs integration will bring pressure and challenge to the operation of power system. Exploiting EV’s characteristics of controllable load and and energy storage, solutions can be designed to reduce the adverse effects on grid and improve the utilization efficiency of power resources by coordinating and optimizing the charging and discharging process. The correspondin research work of the economic dispatch problem with large-scale EVs has been investigated in this paper, and complementary constraints have been used to accurately describe the dynamic characteristics of EV’s behavior.First of all, for the convenience of solving the complementary constraints in subsequent optimization model, general overviews of nonlinear complementary problem used in this paper are presented. Based on the Steff.-Ulbrich local relaxation scheme and modern interior point method, this paper proposes an effective complementary constraints interior point method for solving mathematical programming with complementarity constraints. Relaxation strategy retains the exact expression for the complementary constraint corresponding to sufficiently nondegenerate components and relaxes only remaining complementary constraint. Thus, the modern interior point method can be applied because the feasible set haa been improved. Study has shown that the algorithm has a nice finite termination property in the sense that it is not always necessary that the relaxation parameter has to be driven drow to zero.Then a charging optimizaton model considering large-scale EVs charging demand is proposed to achieve the smallest generation cost by optimizing the EV charging power. Comparisons of generation cost and load level under different charging methods and different size vehicles have shown that the optimal charging method can effectively reduce the generation cost and smooth the peak-valley gap, the higher penetration level of EV, the more economic benefits generated significantly.Based on the above charging optimization model, the dynamic economic dispatch model considering EV’s charging and discharging power is proposed. In this model, the penalty cost of load fluctuations is included in objective function by the way of punishment. The proposed complementary constraints interior point method is applied to obtain the optimal solution of the problem. Numerical simulations on10units system of different size vehicles have verified the effectiveness of the algorithm and the feasibility of the model. The results show that coordinating and optimizing EV’s charging and discharging process can stabilize the load fluctuations and improve the economy and reliability of system operation.