Abstract: The integration of renewable energy increases the likelihood of cascading failures,posing challenges in identifying critical lines during fault propagation.In light of this,a cascading failure simulation model that incorporates the fault voltage ridethrough characteristics of wind turbines and line reliability is built.An indicator evaluation set of line comprehensive risk is also introduced,which encompasses line load loss severity and non-uniformity,and structural vulnerability perspectives.The security risk index and the uneven risk index are defined based on the state-failure-network,the degree of line load loss severity and nonuniformity.Based on the electrical betweenness,a fragile structure index accounting for distributed renewable energy access is proposed.Meanwhile,to measure the overall impact of line disconnection,a fuzzy entropy weight method is employed to define the comprehensive risk index,which considers the network structure and state transition characteristics of the power grid.Numerical examples involving the IEEE 39-bus and IEEE 118-bus systems validate the effectiveness of the proposed method in identifying critical lines.Additionally,mitigation measures for critical lines can significantly reduce the risk of blackouts.