| 引用本文: | 姚 宇,陈武晖,张庚午,郭小龙,刘德福.直流电网稳定性分析的改进节点阻抗方法[J].电力系统保护与控制,2025,53(23):113-126.[点击复制] |
| YAO Yu,CHEN Wuhui,ZHANG Gengwu,GUO Xiaolong,LIU Defu.Enhanced nodal impedance method for stability assessment in DC power grid[J].Power System Protection and Control,2025,53(23):113-126[点击复制] |
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| 摘要: |
| 直流电网中电力电子变流器端口阻抗与直流线路阻抗特性匹配失衡产生的负阻尼将会严重影响直流电网的稳定运行。经典阻抗法在评估直流电网稳定性时，存在因前提假设条件失效以及零极点对消而导致关键模态缺失的固有局限，会造成对系统稳定性的误判。为此，首先分析了导致前提假设条件失效的内在机理，探讨了零极点对消现象的产生机制及主要发生场景。并针对上述问题，提出一种基于广义导纳矩阵的改进节点阻抗求解方法。该方法克服了经典阻抗法在直流电网稳定性分析中的固有局限性，同时解决了导纳/阻抗矩阵分析方法因矩阵阶数升高而导致的节点阻抗求解困难问题，提高了其在大规模系统中的实用性。最后，在PSCAD/EMTDC中分别构建了两端及三端VSC-HVDC系统模型，验证了理论分析的正确性以及所提改进方法的有效性。 |
| 关键词: 直流电网 阻抗分析法 节点阻抗 稳定性分析 |
| DOI：10.19783/j.cnki.pspc.250139 |
| 投稿时间：2025-02-12修订日期：2025-05-13 |
| 基金项目:国家自然科学基金项目资助(51977098)；新疆维吾尔自治区重大科技专项资助(2022A01007-1)；新疆电力公司科技项目资助(SGTYHT/21-JS-223) |
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| Enhanced nodal impedance method for stability assessment in DC power grid |
| YAO Yu1,CHEN Wuhui1,ZHANG Gengwu1,GUO Xiaolong2,LIU Defu2 |
| (1. College of Electrical and Power Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. State Grid Xinjiang Control Center for Power Dispatching, Urumqi 830002, China) |
| Abstract: |
| Negative damping arising from the mismatch between the port impedance characteristics of power electronic converters and the DC line impedance in DC power grids can severely compromise DC system stability. The classical impedance-based method has inherent limitations: when its underlying assumptions fail or when pole-zero cancellation occurs, key dynamic modes may be omitted, leading to incorrect stability assessments. To address this issue, the intrinsic mechanisms behind the failure of the classical assumptions is first analyzed, followed by an investigation into the origin and typical scenarios of pole-zero cancellation. An improved nodal impedance simplification method based on a generalized admittance matrix is then proposed. This method overcomes the inherent limitations of the classical impedance approach in DC grid stability analysis and resolves the computational challenges in nodal impedance extraction caused by the dimensionality growth in admittance/impedance matrix methods, thereby enhancing their applicability to large-scale systems. Finally, two-terminal and three-terminal VSC-HVDC system models are constructed respectively in PSCAD/EMTDC to verify the correctness of the theoretical analysis and the effectiveness of the improved method presented. |
| Key words: DC power grid impedance-based analysis node impedance stability analysis |
