A phase‐plane trajectory vector‐based method for real‐time identification of critical machines

Critical Machines (CMs) identification is the first and most important step of Equivalent-Single Machine Infinite Bus (E-SMIB) based methods such as EEAC and SMIE for transient stability assessment and control. This paper presents a novel real-time CMs identification method based on the Phase-plane Trajectory Vector (PTV) with PMU information support. The proposed method overcomes the drawbacks of conventional CMs identification methods and enables to track the change of CMs during the dynamic process. Only two sample points of all generators from PMUs are required to obtain the PTVs at each moment and the computation of feature matrix, as well as the k-means clustering, is fast and accurate. The application of the PTV based method is verified through cases study in IEEE 39 bus New England power system. Results are compared well with those obtained by conventional methods.