基于频域二次约束的电力系统可扩展小信号稳定性评估
Scalable Small-Signal Stability Assessment of Power Systems Based on Frequency-Domain Quadratic Constraints
- College of Electrical Engineering, Zhejiang University（浙江大学电气工程学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文提出基于频域二次约束的可扩展小信号稳定性评估方法，统一现有判据并引入全乘子条件，通过优化实现定量稳定性认证与设备诊断，降低保守性并有效识别失稳风险设备。
AI中文摘要：
在电力电子主导的电力系统中，由于异构的电网跟随（GFL）和电网构成（GFM）换流器的大规模集成，小信号稳定性分析正变得越来越具有挑战性。经典集中式方法，如特征值分析和广义奈奎斯特准则，提供了直接的稳定性评估工具，但随着系统规模的增大，其可扩展性有限。这促使了对稳定性评估和设备级诊断的可扩展分析方法的开发，并需要保守性更低的稳定性条件。为此，本文提出了一种基于频域二次约束（FQCs）的多换流器系统可扩展小信号稳定性评估方法，并提供了定量稳定性指标。研究表明，现有的若干稳定性条件，包括基于Davis-Wielandt（DW）壳的几何条件、数值域、$x$-$z$图、缩放相对图（SRG）、混合增益-相位条件和无源性条件，都是基于FQC的稳定性条件的特例。这种基于FQC的表述还阐明了这些现有稳定性条件进行分散验证的要求。为进一步降低保守性，开发了一种基于全乘子FQC的稳定性条件，在此基础上构建了一个优化问题，用于利用定量稳定性指标进行可扩展的稳定性认证和设备级诊断，而无需依赖图形检查。结合混合增益-相位条件，该优化问题形成了一个分层筛选-诊断流程，提高了效率。案例研究表明，所提方法比现有准则保守性更低，并能有效识别与潜在失稳风险相关的问题设备。
英文摘要：
Small-signal stability analysis of power electronics-dominated power systems is becoming increasingly challenging due to the large-scale integration of heterogeneous grid-following (GFL) and grid-forming (GFM) converters. Classical centralized methods, such as eigenvalue analysis and the generalized Nyquist criterion, provide direct stability assessment tools but exhibit limited scalability as the system size increases. This motivates scalable analysis methods for stability assessment and device-level diagnosis, and calls for less conservative stability conditions. To this end, this paper proposes a scalable small-signal stability assessment method with quantitative stability indices for multi-converter systems based on frequency-domain quadratic constraints (FQCs). It is shown that several existing stability conditions, including geometric conditions based on the Davis-Wielandt (DW) shell, numerical range, $x$-$z$ graph, scaled relative graph (SRG), mixed gain-phase condition, and passivity condition, are special cases of the FQC-based stability condition. This FQC-based formulation also clarifies the requirements for decentralized verification of these existing stability conditions. To further reduce conservatism, a full-multiplier FQC-based stability condition is developed, based on which an optimization problem is formulated for scalable stability certification and device-level diagnosis using quantitative stability indices without relying on graphical inspection. Combined with the mixed gain-phase condition, this optimization problem forms a hierarchical screening-diagnosis procedure that improves efficiency. Case studies demonstrate that the proposed method is less conservative than existing criteria and can effectively identify problematic devices associated with potential instability risks.
