A new identification method of critical lines for cascading failures

The access of renewable energy improves the probability of cascading failures in power system, which makes it more difficult to identify critical lines in fault propagation. Therefore, based on the state-failure-network, the loss-of-load risk index and uneven risk index are defined considering the degree and unevenness of line loss-of-load, and the fragile structure index considering distributed new energy access is proposed based on the electric betweenness. Considering the network structure and state transition characteristics, the comprehensive risk index is defined by fuzzy entropy weight method to measure the comprehensive impact of line interruption. An example of IEEE39-bus system verifies the effectiveness of the proposed method for critical line identification.