Dynamic Economic Dispatch For Microgrid Considering Risk Operation Cost

Economic dispatch for microgrid plays an important role in the study of microgrid,and it is the key to promote the large-scale industrialization of microgrid.Traditional economic dispatch often ignores the random fluctuation characteristics of renewable energy and the load.Although some consider the impact of volatility,objective function contains only scheduling plan operation cost corresponding to the scheduling output without considering the risk operating cost that microgrid in order to maintain the real-time power balance to conduct power adjustment,and the risk operating cost is inevitable to maintain the real-time power balance.Therefore,it is of great practical significance to study the dynamic economic dispatch for microgrid considering the risk operating cost.Under the background of a large number of distributed power access to microgrid,the economic dispatch of controllable unit is a hot research topic under the influence of random factors.The impact of uncertain factors in microgrid such as wind power,photovoltaic et al lead to the overestimate or underestimate state of operation easily.In order to meet the real-time power balance of the system to ensure the power quality of the user,the power adjustment must be carried out to ensure the balance between supply and demand under the two states.In this paper,we study the economic dispatch problem for microgrid in 24 time periods,and build two power adjustment priority policy and the corresponding risk operation cost model under overestimate state,namely: the priority strategy of the external power grid to conduct power adjustment,and the priority strategy of internal controllable unit to conduct power adjustment;The third power adjustment priority strategy are proposed:hybrid priority power adjustment strategy,the strategy is not limited to a single power adjustment,but is based on the optimal economic choice to conduct real-time power adjustment.For the stochastic optimization model,the risk operating cost of the three different strategies are fused to the objective function by using the chance constrained programming method,and the dynamic economic dispatch model is established,which is based on the planned operating cost and the risk operating cost as the total cost and satisfies various system operation constraints.Aiming at the established model,this paper uses the sample mean method of Bootstrap estimation to determine the confidence interval of random variables,and translate stochastic optimization problem into a deterministic optimization problem effectively,then the numerical simulation of an example microgrid system is carried out.In the simulation analysis,the difference of three power adjustment between total economic operation cost and 24 time period dispatch is compared.The calculation results show the effects with the risk operation cost considered,verify that the third strategy is most economical.The comparisons of the 24 time periods indicate that different priority strategy have different effects on the scheduling results.The validity of the model is verified by numerical simulation.