Study Of The Identification Of Critical Links And Stability On The Power Grids

In recent years,with the complex networks penetration in a number of different disciplines,applying the theory and methods of complex networks to study complex scientific issues of the Internet age has become a new hotspot.Power grid is one of the largest complex networks,efficient and reliable operation of which is essential for people's normal production and life.Applying the theory of complex networks to analyze the topology of power grids and the dynamic characteristics of nodes,which can help us understand the operating mechanism and structural defects of the power grids better.Thus in the actual power grids,we can adopt appropriate measures to prevent the occurrence of cascading failures,and ensure the stable of the power grids.In this paper,based on the previous research on the power grids,considering the topology and dynamics of the power grids,we study the identification of critical links and stability on the power grids.Mainly finished the following works:1.Learn from the idea of Multiple Attribute Decision Making in the theoretical model,and considering the dynamics of nodes at the same time,we propose a method of identifying the critical nodes based on the topology and dynamics of the power grids.First,according to the topology of the networks,we calculate the degree centrality and closeness centrality of each node.Then,considering the dynamic characteristics of the power grids with using the class Kuramoto model of power grids,we calculate respectively the synchronous critical coupling strength of the largest connected subnet after a node being removed,and the time of de-synchronization wave spreading to the entire system after a node being disturbed.Finally,taking comprehensive consideration of the four evaluation indicators,we can get the importance degree of each node on the power grids.After a node being removed,we analyze the anti-disturbance ability of the largest connected subnet,the results show that the proposed method is valid.2?After the specific transmission line being disconnected,according to the variation of cohesion degree of power grid,we propose critical lines evaluation method based on the cohesion degree of power grid.The degree of cohesion of a network depends on two factors:connectivity between nodes and the number of nodes in the network,the average distance of a network can be used to measure the connectivity between nodes.After the line being disconnected,the importance of the line can be determined according to the amount of change in the cohesion degree of the power grid.The calculation results of this paper are compared with the results of the existing critical lines evaluation schemes based on the network performance in the literature,and the simulation is carried out on the topological structure and dynamics.The results show that the method is reasonable and effective.3?We study and analyze the synchronization and stability of the cluster networks composed of power grids,make simulation experiments on the IEEE test networks.By increasing the number of connections between the clusters gradually,making observe of the changes in the steady state order parameter,synchronous critical coupling strength,the maximum intensity of the disturbance which the system can withstand and other parameters on the cluster networks,we study the effect of the number of connections between the clusters on the synchronization performance of cluster networks.The results show that the larger the number of connections between the cluster,the better the synchronization performance of the entire cluster network,the smaller the corresponding synchronous critical coupling strength,while the maximum intensity of the disturbance which the system can withstand greater.In addition,we take a comparative analysis between the power system composed of cluster networks and single power system,study shows that connecting the subnet which has the same structure,we can get a cluster network which has greater synchronization performance,smaller synchronous threshold and stronger anti-disturbance ability than single subnet,and the cluster network composed of the subnet which has the different structure,its synchronization capabilities and anti-disturbance ability are better than single large subnet,weaker than single small subnet,its synchronous threshold smaller than single large subnet,bigger than single small subnet.