Microgrid Scheduling With Source-Load Uncertainty

With the reform of energy structure,new energy sources are being developed more and more,and wind and solar energy have become the main direction of new energy development because of their high cleanliness and abundant reserves.Micro power grid as the main form of new energy grid,with the continuous access of wind power and solar energy,the safe operation of microgrid will be threatened due to the uncertainty of wind power and solar energy.If only the predicted value of wind power and solar energy is used in the scheduling of microgrid,it is no longer possible to ensure the safe operation of microgrid.In addition,with the advance of power market reform,loads of different power consumption modes change their power consumption time and power consumption with the change of electricity price,and the load side is no longer a fixed load,presenting uncertainty.The uncertainty on both sides of source load brings new challenges to micro-grid scheduling.At the same time,the proposed demand response also makes more loads participate in the demand response scheduling and adds new schedulable resources to the micro-grid scheduling.Therefore,aiming at the uncertain characteristics of wind power and load,it is of great significance to make full use of the schedulable resources on both sides of the source and load for micro-grid scheduling to ensure the safe operation of the micro-grid and better absorb wind and solar energy.In this thesis,the source-load uncertain interactive optimal scheduling considering the microgrid economy and reliability is studied for the uncertainty of wind power output as well as load.For the uncertainty on both sides of the source and load,the uncertainty of wind power output is represented by the probability density of Weibull distribution and the uncertainty of load response is represented by the normal distribution,respectively,and in order to analyze the impact caused by the uncertainty,the point estimation method combined with the forward back substitution method is used for the probabilistic tide calculation,Furthermore,for the wind farm output correlation caused by the wind speed correlation of different wind farms,the linear rank correlation coefficient is used to represent the correlation.By introducing Nataf inverse transform,the correlation of non-normal distribution random variables is processed,and the probabilistic power flow calculation considering the wind power correlation is realized.In the microgrid scheduling objective function,the source-side conventional unit operation cost function,wind abandonment cost function,grid loss and load-side compensation cost are considered,and a graded compensation mechanism is introduced in the load-side compensation cost,The interruptible load is graded according to the interrupted quantity,and the reduced load is graded according to the TOU price.The tide calculation result is used as the scheduling model constraint to realize the interactive scheduling of both sides of the source and load,which ensures economy and reliability at the same time.In the simulation validation,Monte Carlo sampling simulation method,three-point estimation method and two-point method are simultaneously used for probabilistic tide calculation,and the results show that the three-point estimation method is close to the Monte Carlo method in terms of accuracy and faster processing speed.The scheduling model is solved by chaotic particle swarm optimization(CPSO)algorithm and the tide calculation is performed by the three-point method.The scheduling results show that the proposed uncertain microgrid source-load scheduling model,which takes into account the flexible load,can reduce the operating cost of the grid,reduce the network loss and improve the utilization of distributed energy,and ensure the system security on the microgrid with source-load uncertainty and wind power correlation.