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In recent years, the sub‐/super‐synchronous oscillation (SSO) caused by grid integration of direct‐drive permanent magnet synchronous generators (D‐PMSG) has attracted wide attention. However, most of the existing stability analysis methods are either complex or cannot quantitatively analyze the influence of parameter changes on system stability. To address the problems, this paper proposes a novel stability analysis method for SSO in the D‐PMSG integrated power system based on closed‐loop transfer function poles. Firstly, the impedance modeling method was introduced to analyze the stability of the D‐PMSG power system. Then, a stability criterion was proposed based on the poles of the closed‐loop function. The proposed criterion is simple and has a clear physical background. The real part of the poles represents the damping while the imaginary part of the pole reflects the oscillation frequency. Finally, simulation results verify the accuracy and effectiveness of the proposed method. Moreover, its application in influence factors for quantitative analysis was also validated. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The dominant modes of the system can be described by the critical eigenvalues, which reflect the stability and stability margin. This paper proposes a dominant mode identification (DMI) method to assess the stability of the grey-box grid-tied converter. First, the analytical relationship between the eigenvalues and the transfer function is clarified based on the small-signal model. Furthermore, the critical eigenvalues are estimated by the system's transfer function. On this basis, the discrete transfer function of the grey-box grid-tied converter is constructed utilizing the frequency sweeping technique. Finally, the critical eigenvalues are determined using the measured data based on the customized particle swarm optimization algorithm. The method can apply to different grid connection scenarios of converter-based components and is easy to implement. The DMI method can not only assess the stability margin of grey-box grid-tied converters in operation, but also predict the stability of black-box converters after being connected to the grid in the planning stage. • The relationship between the frequency responses and the eigenvalues is clarified. • The stability is analyzed according to the dominant mode of the system. • The method can pre-analyze the stability of the black-box converter. • The PSO algorithm for identifying dominant modes is easy to implement. [ABSTRACT FROM AUTHOR]

In this paper, a simplified method for channel capacity estimation has been derived based on the transmission-line theory under the condition of high-bandwidth utilization. This method decouples the channel capacity into several independent components which may help to investigate the effects of backbone and branch, respectively. Analysis of backbone effects with respect to the available bandwidth reveals the applicable condition for the simplified method. Single branch effects are investigated considering branch length together with the loads. Besides, coupling effects caused by branch interactions are studied in a statistical way. The simulation results show great consistencies by using the proposed method and the conventional one and reveal the way that branches affect the channel capacity in different power networks. [ABSTRACT FROM AUTHOR]