Research On Optimal Scheduling Of Microgrid Mixed Integer Programming Based On Chance Constraints

Nowadays,the global energy shortage and the environmental pollution problem are increasing rapidly.How to improve the utilization rate of renewable energy such as scenery has become a hot research topic.Microgrid is a controllable unit which can combine wind power,photovoltaic,load,energy storage and control protection,and it can improve the utilization efficiency of renewable energy such as scenery.The output of renewable energy such as scenery and natural environment is uncertain,which will lead to the increase of the operation risk of microgrid and have a great impact on its optimal dispatching.How to eliminate the influence of these uncertain factors is the key to realize the optimal operation of microgrid.Therefore,this paper studies the optimal scheduling of micro grid including renewable energy such as scenery,based on the opportunity constraint.The main work includes:Firstly,the mathematical models of micro power supply,such as wind turbine(WT),photovoltaic(PV),diesel engine(DE),energy storage system(ESS),are constructed.Considering the uncertainty of scenery and load output,the optimization of micro grid including these units is studied.Then,the paper establishes a new optimal scheduling model based on opportunity constraints,aiming at the lowest comprehensive operation cost of microgrid system.In this paper,we use the deterministic transformation method of opportunity constraint condition based on sampling to deal with multiple random variables in the model,which can transform the opportunity constraint into mixed integer constraint.Moreover,the random variables in the opportunity constraints can be separated,so the transformed mixed integer constraints can be simplified,which greatly reduces the solution time of the model.In order to improve the speed of the model,the objective function is transformed into a mixed integer linear programming function by piecewise linearization.Finally,considering the influence of the forecast error of the wind and the prediction lead time,the multi-scale optimal scheduling model of microgrid is proposed.According to the characteristics of the wind forecast error changing with the prediction lead time,the confidence level of the opportunity constraints at each time is set reasonably.This treatment can further reduce the integrated operation cost of the micro grid dispatching system without increasing the operation risk of the microgrid.