| With the development of modern power technology,large-scale interconnection of power grids has become an inevitable trend.Complex grids create huge economic benefits as well as potential risks.In recent years,the major blackouts occurred both at home and abroad are caused by cascading failures rather than failure of single components.Therefore,it is of great theoretical and practical significance to strengthen the research on power grid risk assessment.In order to solve the problem that traditional risk assessment method can not reflect the risk of power grid cascading failure globally,the characteristics of power transmission are fully considered in this paper,meanwhile,the power distribution and energy flow distribution are combined,which consider the influence of cascade failure from both electrical and topological attributes of the network,then the paper puts forward the asset value calculation model of power grid cascade failure.Select the effective sub-level fault breaking strategy and find the network vulnerable links.At the end,the risk assessment model is proposed based on the work mentioned above.The simulation results show that the method described in this paper can reflect the risk of cascading failure more completely.The comparison with the traditional methods further illustrates the rationality of the proposed method.In order to solve the problem that the value of risk can not directly reflect the state of system risk,the impact of each risk index on the system is fully considered and a risk rating model is proposed based on evidence theory.A fusion algorithm is used to effectively fuse multiple risk indicators of cascade failure.Based on this,the risk level of the branch is obtained through the decision criterion.The simulation results show that the model can effectively overcome the uncertainty of the single risk index,and consider the impact of each index on the system security and can accurately predict the risk of grid cascading failure. |
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