DOI:10.35833/MPCE.2019.000162 Analysis of Mode Interaction in Ultra-low Frequency Oscillation Based on Trajectory Eigenvalue Page view: 0        Net amount: 125 Author: Yusheng Xue1,2,Zijun Bin2 Author Affiliation: 1.State Grid Electric Power Research Institute, Nanjing 211106, China;2.School of Electrical Engineering, Shandong University, Jinan 250061, China Foundation: This work was supported by the Program of State Grid Corporation of China “Theoretical Basis, Algorithm, and Application of Trajectory Eigenvalue Method”. Abstract: Complex phenomena such as prolongedly undamped ultra-low frequency oscillation (ULFO) and eigenmode re-excitation are observed in the simulations of hydroelectric power systems. Emphases are put on nonlinearities and mode interactions, which cannot be analyzed by traditional eigen-analysis methods. In order to investigate the mechanism of the evolvement of the nonlinear dynamic process in ULFO, this paper proposes a method to analyze the mode interactions quantificationally. First, a disturbed trajectory is decoupled into a set of time-varying components. Second, transfer matrices of eigenmodes are extracted along the trajectory. Third, consecutive sequences of eigenvalues and trajectories of components are formed by a proposed technique. Based on the decoupled components and transfer matrices, the mechanisms of mode interactions and inheritance relationships between eigenmodes are analyzed. The causes and developments of the above complex phenomena are revealed by the proposed method in a test two-machine system. Meanwhile, the accuracy of the eigenmode matching technique is verified in the New England system. Keywords: Eigenmode matching ; hydroelectric power system ; mode interaction ; trajectory eigenvalue ; ultra-low frequency oscillation Received:November 19, 2019               Online Time:2020/12/03 View Full Text       Download reader