| 引用本文: | 李霞林,张晨,郭力,张野,高飞,王智,李鹏飞,王成山.锁相环同步VSC接入弱网下的低频动态稳定性分析模型与机理研究[J].电力自动化设备,2022,42(8): |
| LI Xialin,ZHANG Chen,GUO Li,ZHANG Ye,GAO Fei,WANG Zhi,LI Pengfei,WANG Chengshan.Low frequency dynamic stability analysis model and mechanism research for PLL-synchronized VSC connected to weak grid[J].Electric Power Automation Equipment,2022,42(8): |
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| 摘要: |
| 基于锁相环(PLL)同步接入弱网的电压源型换流器(WG-VSC)存在由“外环-PLL-弱网”交互主导的低频动态(LFD)稳定问题。为清晰揭示各关键环节及其交互对WG-VSC的LFD影响机理，提出一种等效PLL模型。首先建立了适用于多种典型外环控制模式的WG-VSC的LFD分析的基本模型，该模型包含原PLL环节及耦合了外环、电网强度及VSC运行点信息的“外环-弱网”环节。其次，将“外环-弱网”环节划分为有功侧外环对PLL的影响路径及无功侧外环所引入的对PLL的影响路径，以清晰表征VSC外环与PLL的交互关系。然后，基于LFD主导模态将“外环-弱网”环节简化为一阶环节，并结合原PLL的PI控制环节，得到保持足够LFD分析精度的二阶等效PLL模型，并基于该模型分析和揭示了“外环-PLL-弱网”的交互对WG-VSC的LFD的影响机理。最后，基于详细开关模型的时域仿真结果验证了等效PLL模型的有效性和分析结果的准确性。 |
| 关键词: 电压源型换流器 低频动态 弱网 等效锁相环模型 控制环节交互 机理分析 |
| DOI：10.16081/j.epae.202202024 |
| 分类号:TM712 |
| 基金项目:国家自然科学基金资助项目(51977142)；国家重点研发计划资助项目(2020YFB1506803) |
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| Low frequency dynamic stability analysis model and mechanism research for PLL-synchronized VSC connected to weak grid |
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LI Xialin1, ZHANG Chen1, GUO Li1, ZHANG Ye2, GAO Fei3, WANG Zhi1, LI Pengfei1, WANG Chengshan1
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1.Key Laboratory of Smart Grid of Ministry of Education, Tianjin University, Tianjin 300072, China;2.State Key Laboratory of HVDC, Electric Power Research Institute, China Southern Power Grid, Guangzhou 510663, China;3.Key Laboratory of Power Transmission and Power Conversion Control of Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
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| Abstract: |
| The LFD(Low Frequency Dynamic) stability problem of WG-VSC(Weak Grid connected Voltage Source Converter) based on PLL-synchronized is dominated by “outer loop-PLL-weak grid” interaction. To reveal the influence mechanism of key loops and their interactions on LFD of WG-VSC, a PLL-equivalent model is proposed. Firstly, the basic LFD analysis model suitable for many typical outer loop control modes is put forward, which contains original PLL loop and “outer loop-weak grid” loop coupled with outer loop, grid strength and information of VSC operation point. Secondly, the “outer loop-weak grid” loop is divided into two parallel paths, one of which shows the impact of active-side outer loop on PLL, and the other shows the additional influence on PLL induced by reactive-side outer loop. Thirdly, the “outer loop-weak grid” loop is simplified into a first-order loop based on dominant modes of LFD, and the second-order PLL-equivalent model that can maintain sufficient accuracy for LFD analysis is derived combined with the PI control loop of original PLL. Based on the above model, the influence mechanism of “outer loop-PLL-weak grid” interaction on LFD of WG-VSC is analyzed and revealed. Finally, the effectiveness of PLL-equivalent model and the accuracy of analysis results are verified by the time-domain simulative results based on detail switch model. |
| Key words: VSC low-frequency dynamic weak grid PLL-equivalent model interaction of control loops mechanism analysis |
