Research On Critical Parts Identification And Cascading Failure Sequence Prediction Method In Power Grid

With the continuous development of modern power system,the scale of power grid is getting larger,transmission distance is getting longer,power supply scope is getting wider,and the voltage level,generator capacity and load of power grid are getting higher,which puts forward higher requirements for the safe and reliable operation of power grid.The frequent large-scale blackouts have not only caused serious economic losses,but also caused chaos of a short time in the society where people live.Therefore,according to the operation characteristics of the power grid,it is of great practical significance to study the critical parts and the cascading failure sequence in order to prevent and reduce the occurrence of large-scale blackouts in the power grid.Based on the characteristics of topological structure and power flow distribution in power grids,this paper studies the critical parts and the cascading failure sequence that affect the safe and reliable operation of power grids.Firstly,the topological model and characteristics of power grid based on complex network theory are studied and analyzed,and the established topological model is taken as the theoretical basis for identifying the critical parts of power grid.Secondly,the evaluation indices of evaluating the lines importance are established from the aspects of power network topology and line parameters,and a more comprehensive method of identifying critical lines is proposed by using the comprehensive weighting method of game theory.According to the different characteristics of transmission information value in different types of nodes,an improved PageRank algorithm is formed to quickly evaluate the importance of nodes,and a critical node identification method is proposed by considering node voltage value.Then,taking critical parts as initial faults,the basic indices to characterize the current risk degree of power grid lines are established,and a cascading failure sequence prediction method is formed by using the D-S evidence theory.Finally,the critical parts are identified in IEEE 39,118-bus system and a provincial power grid as test examples,the critical parts are identified,and the feasibility and validity of the identification method are verified according to the change of network transmission efficiency index.The operational model of IEEE 39-bus system is built in PowerWorld Simulator simulation software to predict cascading failure sequence,and the validity of the prediction method is verified by comparative analysis.