(1. State Grid Jiangsu Electric Power Maintenance Branch Company, Suzhou 215131, China; 2. State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China)

Probabilistic load flow (PLF) is used to effectively and efficiently assess the static security of power systems with large-scale wind power generation. PLF is solved by the analytical method to improve its computational efficiency. PLF is implemented based on sequence operation theory to reduce the requirement for base data and to ensure its practicality. Security indices are defined based on PLF to obtain quantitative assessment of system security rapidly. Security indices include two aspects: security probabilities and associated security risks. Vulnerability analysis is achieved based on the security indices of components. The effectiveness and accuracy of the proposed method are verified by case studies with the IEEE-RTS 79 bus system. Compared with traditional method for stochastic security assessment, the proposed method has higher computational efficiency and is practical for security assessment of power systems with intermittent energy integration.