This paper focuses on interaction between two closed‐connected high‐voltage direct current (HVDC) lines. This interaction is studied by employing high‐fidelity nonlinear modelling in MATLAB/Simulink software environment. In order to describe the mechanism behind the HVDCs interaction, both nonlinear time‐domain simulations and modal analysis of the coupled HVDC links have been performed. System small‐signal stability has been assessed, and the path of interactions has been identified by computing the participations of various states in the oscillatory modes; this sets the preliminaries for a global, grid‐oriented HVDCs control design approach. After the detailed analysis of newly identified coupling oscillations, the minimal modelling requirements to put them into evidence have also been studied; this significantly facilitates the analysis in a realistic large‐scale grid context.

中文翻译：

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交流电网中紧密直流输电线路之间的相互作用研究：非线性和模态混合分析方法

本文着重研究两条闭合连接的高压直流（HVDC）线之间的相互作用。通过在MATLAB / Simulink软件环境中采用高保真非线性建模来研究这种相互作用。为了描述HVDC交互作用背后的机制，已对耦合的HVDC链路进行了非线性时域仿真和模态分析。已经评估了系统的小信号稳定性，并通过计算振荡模式下各种状态的参与来确定了相互作用的路径；这为全球，面向电网的高压直流输电控制设计方法奠定了基础。在对新近识别出的耦合振荡进行详细分析之后，还研究了将其作为证据的最低建模要求。