Research On Cascading Failure Modeling And Robustness Of Power Grids Based On Complex Networks

With the development of society and the improvement of people's living standards,people have higher and higher requirements for the reliability of the power grid,and frequent power failures have made the country pay more and more attention to the construction of reliable and robust power systems.In recent years,many major power outages have caused cascading faults in the power grid to attract widespread attention from scholars at home and abroad.Research on grid cascading faults and building a robust smart grid have become hotspots.In response to this problem,lots of researchers have proposed different grid cascading failure simulation models from various perspectives.From the perspective of complex networks,this paper uses complex network analysis methods to model and simulate grid cascading faults and robustness is studied,which are summarized as follows:1.Combining the actual physical characteristics of the power grid,this paper proposes a new cascade failure model based on vulnerability indicators of electric betweenness.The model adopts the capacity load model and the principle of nearest neighbor allocation,which can overcome the shortcomings of the existing model that assume that the grid power flow only flows along the shortest path between the busbars.Based on the electrical median of Kirchhoff,which can make up for the shortcomings of the existing model that assume that the grid power flow only flows along the shortest path between the busbars.The research shows that the model based on electric betweenness is superior to the model based on betweenness.2.Based on the proposed grid cascading failure model,the effects of tolerance parameters and load distribution strategies on the robustness of the grid are studied.The scale of the largest subgraph and the load loss rate are introduced to measure the robustness of the grid considering both connectivity and power supply capabilities.The simulation results show that selecting the appropriate tolerance parameters and load distribution strategy can guarantee robustness of the grid and the construction cost of the power grid is saved at the same time.At the same time,the influence of node types on the robustness of the power grid is studied,and it is found that the failure of power generation nodes has the greatest impact on the robustness of the power grid.It is beneficial to improve the network robustness to give priority to protecting power generation nodes under limited resources.And the power grid's tolerance to node failure is analyzed.3.The power grid-communication network double-layer network is modeled,and the influence of different connection methods,network structure properties and the proportion of dispatching center nodes on the robustness of the smart grid is studied.Studies have shown that selecting nodes with large value of electrical betweenness in the power grid and connecting nodes with large value of betweenness in the communication network,while protecting key nodes,can effectively improve the robustness of the smart grid.In addition,it is found that setting the appropriate network average degree,average path length,and average path length according to the lower power network when constructing the upper communication network is also a strategy to improve the robustness of the power network-communication network double-layer network.At the same time,simulation shows that when there are fewer dispatching center nodes,appropriately increasing the proportion of dispatching center nodes can significantly improve the robustness of the two-layer coupling networks.