Vulnerability Assessment Model of Power Grid Cascading Failures Based on Fault Chain and Dynamic Fault Tree

Cyber-physical security of the smart grid obtains increasing attention. Critical transmission lines have a major impact on large-scale cascading failures in modern power grids. In this paper, we proposed a predicting model of cascading failures based on the fault chain theory and Fuzzy C-Means. The development process of cascading failures in a power grid is described based on the fault chain and dynamic fault tree theories. Loading rate, coupling relationship of sequent tripped lines and power flow variation are considered in the proposed method to predictive the fault chains comprehensively. A novel branch vulnerability assessment method is proposed based on the fault chain and dynamic fault tree theories to identify critical branches which have a significant impact on cascading failure expansion. The effectiveness of the proposed assessment model is tested based on IEEE 39-bus system.