文章摘要
徐路遥,兰洲,陈飞,等.弱电网下无功控制对并网变流器稳定性影响分析[J].电力系统自动化. DOI: 10.7500/AEPS20180731006.
XU Luyao,LAN Zhou,Chen Fei, et al.Analysis on Impact of Reactive Power Control on Stability of Grid-connected Converter in Weak Grid[J].Automation of Electric Power Systems. DOI: 10.7500/AEPS20180731006.
弱电网下无功控制对并网变流器稳定性影响分析
Analysis on Impact of Reactive Power Control on Stability of Grid-connected Converter in Weak Grid
DOI:10.7500/AEPS20180731006
关键词: 并网变流器  弱电网  阻抗模型  无功控制外环  小干扰稳定性
KeyWords: grid-connected converter  weak grid  impedance-based model  reactive power control loop  small-signal stability
上网日期:2019-06-11
基金项目:国网浙江省电力有限公司科技项目
作者单位E-mail
徐路遥 浙江大学电气工程学院 xuluyao@zju.edu.cn 
兰洲 国网浙江省电力公司经济技术研究院 lanzhou _u _zju@163.com 
陈飞 国网浙江省电力公司经济技术研究院 chen_en_fei@sohu.com 
王晓菲 浙江大学电气工程学院 eewangxf@zju.edu.cn 
袁辉 浙江大学电气工程学院 Yuan_Hui@zju.edu.cn 
辛焕海 浙江大学电气工程学院 xinhh@zju.edu.cn 
摘要:
      可再生能源经变流器接入弱电网时,变流器向电网输出无功功率有利于提高并网点的电压质量,但是无功控制的动态特性对变流器系统的稳定性有重要的影响。为分析此影响,本文建立了采用定无功功率控制策略下变流器的阻抗模型,通过分析无功外环动态改变所引起的变流器阻抗模型中各元素阻抗特性变化,判断无功外环动态对系统稳定性的影响,并采用广义奈奎斯特判据验证上述分析结论。其次,采用特征根轨迹法,分析了计及无功外环动态时无功外环比例参数及电网强度的变化对系统稳定性的影响,结果表明弱电网下无功外环可能引发中高频振荡问题。最后,通过基于RT-LAB的控制器在环仿真进行验证。
Abstract:
      When renewable energy is connected to weak grids via converters, the converters deliver reactive power to the grid can improve the voltage quality at the point of common coupling. However, the dynamic of the constant reactive power control loop affects the stability of a grid-connected converter system significantly when connected to weak grids. To explore the impacts of the constant reactive power control loop on the system’s stability, this paper proposes the im-pedance models of converters, in which the active power control loop including the DC-link voltage control and the constant active power control are considered. The impacts of constant reactive power control loop on system’s stability are estimated by analyzing the elements of the system’s impedance model with variations of the constant reactive power loop’s dynamics. To verify the above theoretical analysis, the Generalized Nyquist Criterion is applied. Moreover, the eigenvalue analysis method is used to explore the impacts of the constant reactive power control loop’s proportion-al gain and grid inductance on system’s stability. The root loci results reveal that the constant reactive power control loop may cause medium-high frequency oscillations when the converters are connected to weak grids. Finally, the time-domain simulations and hard-ware-in-the-loop (HIL) simulation are conducted to validate the theoretical analysis results.
查看全文   查看附录   查看/发表评论  下载PDF阅读器