Trajectory section eigenvalue method for nonlinear time-varying power system

• Published in: International journal of electrical power & energy systems 2019-05, Vol.107, p.321-331
• Main Authors: Xue, Yusheng, Bin, Zijun
• Format: Article
• Language: English
• Subjects: Low-frequency oscillation; Nonlinear time-varying factors; Piecewise linearization; Trajectory reconstruction; Trajectory section eigenvalue
• ISSN: 0142-0615; 1879-3517
• DOI: 10.1016/j.ijepes.2018.11.030

•A method is proposed to extract the instantaneous oscillation factors.•The proposed method has a higher accuracy, compared with signal analysis methods.•A method is proposed to study the interaction of multi-eigenmodes.•Some complex phenomena can be explained by the proposed methods.•The validity and universality of the proposed method have been strictly clarified. Low-frequency oscillation is usually regarded as a small disturbance problem. Traditional methods describe oscillation through eigenvalues obtained by linearized equations at the equilibrium point. Obviously, nonlinear time-varying factors are ignored. This article introduces a trajectory section eigenvalue method that can reflect the influences of complex models and fault scenarios. Based on this theory, a trajectory reconstruction method is proposed to accomplish the decoupling of multi-eigenmodes in the time domain. On the premise that the numerical integration is accurate, the trajectory section eigenvalue and trajectory reconstruction methods can be used to study the dynamics of the oscillation and interaction of multi-eigenmodes. Simulation test results show the validity of the proposed methods. The mechanism of low-frequency oscillation is illustrated by trajectory section eigenvalues and trajectory reconstruction methods from a new perspective. These methods can be used as effective tools for theoretical research and engineering applications in power systems.