| As a small power system with complete generation / transmission / distribution / power function,microgrid is of great importance in giving full play to the superiorities of DG technology and boosting the flexibility of power supply and power quality,and maximizing the use of renewable energy.Meaning,it has a significant contribution in building the strong smart grid with Chinese characteristics.However,due to the different operating modes of the distributed generation in the microgrid,it brings many challenges to the microgrid power optimal dispatch and the microgrid power optimal dispatch has become the focus of the research on the related technology of current microgrid.Firstly,this paper analyzes and summarizes the current situation of the research on the economy,the uncertainty of the uncontrollable DG output,the characteristics of the energy storage unit and the optimization algorithm in microgrid power optimal dispatch,then detailed introduced the principle,characteristic and mathematical model of several distributed generation whose the development of technology is relatively mature.Given the different operating characteristics of the microgrid under the different modes and for the sake of giving full play to the superiorities of DG technology and make the microgrid operate economically and reliably,a kind of microgrid optimal dispatching model considering the operating cost and environmental benefit of microgrid under different operating modes is put forward on the basis of meeting the related constraints in the system,and according to the time-sharing peak-valley price mechanism to develop the corresponding microgrid optimization scheduling strategy.Meanwhile,as to such shortages as being easy to obtain partial optimization and slow search speed of the traditional intelligent search algorithm,this paper proposes a chaos-free search hybrid algorithm(C-FS)by combining the perturbation of chaos theory and the elitist tactics.The simulation results show that the economy and the reliability of the microgrids in the modes of grid-connected operation are greatly improved comparing to the modes of isolated-connected operation due to the effective support of the external network;and the proposed C-FS hybrid algorithm in this paper has a significant improvement in both the search speed and the convergence accuracy,and it has certain engineering practical value.Secondly,aiming at reducing the charging and discharging depth of the battery and improve its service life,this paper puts forward the equivalent cycle life model of the battery by using the rain flow counting method,and constructs a optimal dispatching model of the multi-objective microgrid which is considering the operating cost of the microgrid and the cost of battery life and the environmental benefit under the condition of satisfying the relevant constraints in the system.At the same time,considering the conflicting characteristics of each sub-goal in multi-objective optimization problem and on the base of the full study of the fuzzy mathematics theory,the maximum fuzzy satisfaction model of multi-objective optimization problem is established,which transforms multi-objective optimization problem into single-objective optimization problem,and the improved particle swarm algorithm is used to solve the problem in this paper.The simulation results show that the multi-objective optimization model can better coordinate the economy and environmental protection of the microgrid.What's more,it can effectively reduce the life loss and improve the service life of the battery,and has certain guiding significance for the optimization of the microgrid power optimal dispatch which includes the battery.With the microgrid demonstration project has been established,the research on the microgrid power optimal dispatch continues to develop,but also faces many new problems and challenges,how to effectively improve the economy,security and reliability of the microgrid operation also needs further study. |
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