华文,董炜,叶琳,李斯迅,张哲任,徐政
HUA Wen,DONG Wei,YE Lin,LI Sixun,ZHANG Zheren,XU Zheng

• 1:国网浙江省电力有限公司电力科学研究院
• 2:国网浙江省电力有限公司
• 3:浙江大学电气工程学院

摘要(Abstract)：

PLL-GFC（基于锁相环的构网型换流器）具备频率与电压调节能力，然而目前对其接入高压交流电网后的暂态同步稳定性缺乏深入了解。为此，对PLL-GFC型MMC-HVDC（模块化多电平换流器型高压直流输电）暂态同步稳定机理展开研究。首先，介绍PLL-GFC型MMC-HVDC控制策略并分析其功率响应特性。然后，建立MMC-HVDC并网系统暂态同步稳定模型，采用相图曲线方法分析电网故障后换流器失稳机理以及电网电流动态变化对其暂态同步稳定性的影响。研究发现稳定平衡点的存在是换流器并网系统故障后暂态稳定的关键因素，由此提出通过动态调节有功电流指令值来提升暂态同步稳定性的增强措施。最后，通过PSCAD/EMTDC搭建电磁暂态仿真模型，验证了失稳机理分析的正确性与增强措施的有效性。
Phase-locked loop-based grid-forming converters(PLL-GFCs) can regulate frequency and voltage. However, the transient synchronization stability after their connection to the high-voltage AC power grid is unclear.Therefore, the transient synchronization stability mechanism of the PLL-GFC-based MMC-HVDC(modular multilevel converter-based HVDC) systems is studied. Firstly, the control strategy of the PLL-GFC-based MMC-HVDC systems is introduced, and the power response characteristics are analyzed. Secondly, the grid-connected MMCHVDC systems′ transient synchronization stability model is built. The instability mechanism of the converters after grid faults and the influence of the dynamic changes of the grid current on the transient synchronization stability are studied based on phrase diagram curves. It is concluded that the equilibrium point is crucial to the transient stability after the fault occurs on the inverter-connected power grid. Therefore, an enhancement measure to improve the transient synchronization stability by dynamically adjusting active current command values is proposed. Finally, an electromagnetic transient simulation model is built by PSCAD/EMTDC to verify the correctness of the instability mechanism analysis and the effectiveness of the enhancement measure.

关键词(KeyWords)： 暂态同步稳定性;锁相环;构网型换流器;模块化多电平换流器型高压直流输电;相图曲线
transient synchronization stability;phase-locked loop;grid-forming converter;MMC-HVDC;phase diagram curve

Abstract:

Keywords:

基金项目(Foundation): 国网浙江省电力有限公司科技项目（5211DS21N005）

作者(Author): 华文,董炜,叶琳,李斯迅,张哲任,徐政
HUA Wen,DONG Wei,YE Lin,LI Sixun,ZHANG Zheren,XU Zheng

DOI: 10.19585/j.zjdl.202301002

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