MMC型柔性直流输电系统的中高频振荡无源阻尼抑制策略  

Passive damping suppression strategy for medium and high frequency oscillations in MMC type flexible DC transmission systems

作　　者：聂永辉[1] 张德伟 高磊 吴春迎 张瑞东 NIE Yonghui;ZHANG Dewei;GAO Lei;WU Chunying;ZHANG Ruidong(College of Electrical Engineering,Northeast Electric Power University,Jilin 132012,China;China Electric Power Research Institute Co.,Ltd.,Beijing 100192,China)

机构地区：[1]东北电力大学电气工程学院,吉林吉林132012 [2]中国电力科学研究院有限公司,北京100192

出　　处：《电力系统保护与控制》2024年第16期141-149,共9页Power System Protection and Control

基　　金：吉林省自然科学基金项目资助(20230101216JC)。

摘　　要：较长的控制链路延时会导致基于模块化多电平换流器(modular multilevel converter,MMC)的柔性直流输电系统阻抗在高频段出现负阻尼区间,易与交流系统分布电容相互作用引发高频振荡。现有有源阻尼抑制策略虽可有效抑制高频振荡,但会恶化中频段阻抗特性,增加中频振荡发生的风险。为有效抑制中高频振荡,提出在MMC交流侧母线处并联无源阻抗重塑装置的无源阻尼抑制策略。首先,推导出MMC简化模型并验证其准确性。其次,根据奈奎斯特稳定判据与最小功率损耗约束设计阻抗重塑装置参数,实现MMC系统阻抗重塑。最后,应用阻抗法对比分析重塑前后MMC系统阻抗特性,分析阻抗重塑装置对MMC系统阻抗的修正效果。在PSCAD/EMTDC中搭建含无源阻抗重塑装置的MMC电磁暂态仿真模型。仿真结果表明,该抑制策略在中高频段均可有效抑制MMC系统的振荡现象,对系统稳态特性影响小,且基频功率损耗低。Long control link delays can lead to negative damping in the impedance range of flexible DC transmission systems based on modular multi platform converters(MMC).These can easily interact with distributed capacitors in the AC system and cause high-frequency oscillations.Although existing active damping suppression strategies can effectively suppress high-frequency oscillations,they will deteriorate the impedance characteristics of the mid frequency range and increase the risk of mid frequency oscillations.To effectively suppress mid-to-high frequency oscillations,this paper proposes a passive damping suppression strategy by paralleling a passive impedance reshaping device at the AC side bus of the MMC.First,an MMC simplified model is derived and its accuracy is verified.Secondly,impedance reshaping device parameters are designed based on the Nyquist stability criterion and minimum power loss constraint to achieve impedance reshaping of the MMC system.Finally,the impedance method is applied to compare the impedance characteristics of the MMC system before and after reshaping,and the correction effect of the impedance reshaping device on the impedance of the MMC system is analyzed.An MMC electromagnetic transient simulation model with a passive impedance reshaping device is built in PSCAD/EMTDC.The results show that this suppression strategy can effectively suppress the oscillation phenomenon of the MMC system in the mid-to-high frequency range,with little impact on the steady-state characteristics of the system,and low fundamental frequency power loss.

关 键 词：柔性直流输电 MMC简化模型 中高频振荡 阻抗稳定分析 无源阻抗重塑装置 

分 类 号：TM46[电气工程—电器] TM721.1