Research On Power Flow Calculation And Reliability Evaluation For Large Scale Active Distribution Network

The large-scale development of distributed energy,the significant increase in demand for electricity,and the extensive use of new digital monitoring equipment have caused fundamental changes in the structure and properties of the distribution network,making the traditional distribution network transition to large-scale active Distribution network.Due to the large amount of data,the traditional basic calculation method is difficult to meet the computational requirements of large-scale active distribution network in terms of convergence speed.To this end,this paper studies the power flow calculation and reliability assessment method from the characteristics of big data,and strives to significantly improve the basic calculation speed on the basis of accuracy.Firstly,the data sources and data characteristics in the active distribution network are summarized.Based on this,the common information model of distribution network is designed.The information attributes of the feeder module,the load module,the power generation unit module,the network topology module,and the distribution network operation module are constructed,and the bearing relationships between the modules are also described.Secondly,the deterministic power flow calculation method and the uncertain interval power flow calculation method for large-scale active distribution network are studied.Parallel computing is designed to replace the serial computational steps of the traditional Newtonian method,and the pre-push back method is applied to the interval calculation.By comparing with the classical monte carlo method,the advantages of the proposed strategy in terms of accuracy convergence and speed are verified.In addition,the simulation example also verifies the relationship between the fluctuation interval and the root node parameters.Then,the reliability evaluation method of large-scale active distribution network is studied.To improve the evaluation efficiency,the reliability evaluation of distribution network is divided into three stages: feeder topology analysis,feeder zoning and fault zoning.Each stage is designed with corresponding convergence speed improvement scheme.In the feeder topology analysis phase,the feeder topology analysis speed is improved by replacing the traditional direct search method with hierarchical partition search and segment parameter superposition.In the feeder partitioning stage,the feeders with similar influences are partitioned and equivalently reduced by updating and compressing the mating matrix,which greatly simplifies the reliability evaluation system.In the fault partition stage,the fault impact consequence table is automaticallyobtained by transforming the adjacency matrix.The simulation example demonstrates the effectiveness of the proposed method and proves that reasonable allocation of distributed generation can improve the reliability of the distribution network.Finally,a large-scale active distribution network computing platform is constructed.Based on the message communication interface language,the platform's overall information interaction framework is constructed,and Hadoop technology is used to design the file system and database.At last,a software/hardware support system with parallel computing functions,scene interaction,reliability analysis,and power flow calculation is formed.