Research On Bi-level Coordinated Optimized Operation Strategy Of Microgrid Cluster

In order to advance the strategic goal of “three types and two networks,world-class” proposed by the State Grid in early 2019,China has paid more and more attention to the development and innovation of the energy industry.As the main form of receiving renewable energy,microgrid can effectively improve energy utilization rate,and has been widely used in modern power system.However,in recent years,the scale of microgrid has been continuously expanded,which ha s exposed problems such as the limited capacity of a single microgrid and the low reliability of power supply.In order to solve the above problems,related scholars have proposed the concept of microgrid cluster.Through the energy mutual assistance between the microgrid,the renewable energy penetration rate can be further improved and the economic benefits of the grid can be improved.Therefore,it is of great sign ificance to study the coordinated and optimized operation strategy of microgrid cluster.Aiming at the related content,the dissertation mainly researches from the following aspects:The development status of microgrid and microgrid cluster are briefly described.The basic characteristics and structure of microgrid cluster are introduced.The problems existing in the current economic optimization operation of microgrid cluster are explained.The principles and operating characteristics of distributed power generation units in the microgrid cluster system are analyzed.and corresponding mathematical models are established to provide a theoretical basis for the subsequent research content.Aiming at the multi-objective optimization problem,an improved artificial bee colony algorithm is proposed.On the basis of the original artificial bee colony algorithm,Gaussian mutation and chaos disturbance are added to improve the local search ability and robustness of the algorithm,and effectively avoid ing algorithm premature and falling into local optimality.The optimization results of the algorithms are compared through four classic test functions.From the simulation resu lts,the optimization performance of the improved artificial bee colony algorithm is significantly improved.Aiming at the problem of reactive power optimization of microgrid in microgrid cluster,considering various constraints in the microgrid,a mathematical model of reactive power optimization with minimum active network loss and minimum voltage deviation as objective functions is established.In order to overcome the influence of the randomness of wind power and photovoltaic output on the optimization results,a Latin hypercube sampling method is used to simulate its output scene.K-means clustering is used to reduce the generated scene,which can effectively reduce the amount of calculation while ensuring the accuracy and diversity of the scene.Then the improved artificial bee colony algorithm is used to solve the objective function s,and simulation analysis is performed in the IEEE-33 node test system,which verifies the effectiveness and feasibility of the proposed strategy.Based on the bi-level optimization theory,the optimal operation model of the microgrid cluster is established.The upper layer takes the micro grid cluster as the research object and establishes a mathematical model with the minimum overall operating cost as the goal.As a lower layer research object,the microgrid considers the economic benefits and environmental benefits,and establishes the objective function with minimal operating costs,power losses,power fl uctuations,and pollutant emissions.The improved artificial bee colony algorithm is used to solve the objective function.Finally,the effectiveness of the proposed strategy is verified by simulation.