AI 中文总结
本文通过案例研究揭示了基于RMS的换流器型电网稳定性评估的局限性，提出了dq坐标系下保留电磁动态的建模方法，可准确识别不稳定模式，为相关小信号分析提供可行路径。
AI 中文摘要
电力电子换流器在工业电网中的渗透率不断提高，在远高于传统电力系统机电范围的频率上引入了稳定性挑战。商业软件工具通常使用基于均方根（RMS）模型的特征值进行稳定性分析，这些模型假设网络为准稳态，因此忽略了设备的电磁动态特性——这是电力系统分析中的标准做法。本文呈现了一个工业电网的案例研究，其中传统的基于RMS的特征值分析预测运行稳定，而详细的电磁暂态（EMT）仿真显示振荡不断增长，表明存在不稳定性。为弥合这一差距，我们引入了一种替代建模方法，该方法在旋转dq参考坐标系中构建网络动态，保留电磁动态的微分方程。所得模型可进行特征值分析，能正确识别不稳定模式，与EMT仿真结果一致。我们的研究结果凸显了基于RMS的稳定性评估在换流器主导电网中的根本局限性，并证明dq坐标系下的动态阻抗模型为涵盖高频换流器-网络相互作用的准确小信号分析提供了可行途径。
英文摘要
The increasing penetration of power electronic converters in industrial grids introduces stability challenges at frequencies well above the electromechanical range of traditional power systems. Commercial software tools typically perform eigenvalue-based stability analysis using root-mean-square (RMS) models that assume a quasi-stationary network, thereby neglecting electromagnetic dynamics of assets --- which is standard practice in power system analysis. This paper presents a case study of an industrial grid where the conventional RMS-based eigenvalue analysis predicts stable operation, while a detailed electromagnetic transient (EMT) simulation reveals growing oscillations, indicating instability. To bridge this gap, we introduce an alternative modeling approach that formulates the network dynamics in the rotating $dq$ reference frame, retaining the differential equations of electromagnetic dynamics. The resulting model enables eigenvalue analysis that correctly identifies the unstable modes, consistent with the EMT simulation results. Our findings highlight a fundamental limitation of RMS-based stability assessment for converter-dominated grids and demonstrate that dynamic impedance models in the dq frame provide a viable path toward accurate small-signal analysis encompassing high-frequency converter-network interactions.
