Key Laboratory of Smart Grid of Ministry of Education Tianjin University Tianjin 300072 China;
Key Laboratory of Smart Grid of Ministry of Education Tianjin University Tianjin 300072 China;
Key Laboratory of Smart Grid of Ministry of Education Tianjin University Tianjin 300072 China;
Key Laboratory of Smart Grid of Ministry of Education Tianjin University Tianjin 300072 China;
Security region; Composition; Power flow security; Static voltage stability small-disturbance; stability; Transient stability; Dynamics nature; Topological and geometric characteristics; Hyperplane;