Analysis Of The Evolution Of Self-Organized Critical Law Of Power Grid Based On Complex Network Theory

With the continuous progress of the social economy,the demand for electricity has increased rapidly.In order to meet the demand for electricity load,the scale of the power grid has also expanded and becomes more and more complex.The interconnection of large power grids allows the resources to be optimally deployed over a wide range of areas,also expanding the range of possible system disturbances.At present,the complex network theory is used to analyze the overall characteristics of large-scale power grids,and then the occurrence and propagation of cascading failures are analyzed to study the evolution law of the self-organized critical state of the power grid in this state.In addition,work research on the modeling of cascading failures and identification of self-organized critical states is carried out.The centralized access of wind power will result in a dense structure of the power grid,and the power of the system will become more complex,thus giving rise to new features in the development of self-organized critical state of the power grid.In the third chapter,the network topology entropy and power flow entropy will be used to measure the variation of grid structure and distribution after the wind farms are connected to the grid.The study found that after wind power is centralized access,the network topology entropy will be reduced due to the increased power transmission channel of the wind power delivered.When the output of wind power exceeds the absorptive capability of local load,the system's power flow entropy will increase.Due to the instability of wind power,fluctuations in output can also lead to an increase in the power flow entropy of the system.The operating status of the grid will evolve toward the self-organized critical point.After analyzing the self-organized critical characteristics of the power grid,the inhomogeneity of the distribution of the line load rate and the node's ability to withstand the power transmission of electrical energy will have an important impact on the self-organized critical state of the system.For the line load rate distribution characteristics,the average semi-variance index is used to identify the self-organized critical states of the power system.In terms of the node's ability to withstand the transmission of power,when a small number of nodes are subjected to a huge power transfer task,the system will enter a self-organized critical state,and the power flow inlier distribution of the nodes will also presentt the power law distribution characteristics,so the use of node flow distribution distribution index characterization Hidden failure model based on the complex network theory is simulated for the 30-node system and the results of the calculation verify the validity of the proposed index.