摘要
双馈风电场经柔直接入交流电网可能成为未来“三北”地区大规模风电外送的输电方式。但是双馈风机与柔直系统之间的相互作用存在引发次同步振荡的风险。为此,该文在建立双馈风电场经柔直接入交流电网的系统等值模型的基础上,通过阻抗法分析次同步振荡产生的机理;研究风电场并网机组台数、风速、负荷等因素对次同步振荡特性的影响;同时引入变流器控制器参数的灵敏度指标,分析各控制器参数对系统虚拟阻抗的影响。结果表明,特定运行条件易引发系统的次同步振荡,双馈风电机组在次同步振荡频率上表现出“负电阻、感性电抗”性质,与柔直风场侧变流器(“正电阻、容性电抗”)构成等效的负电阻谐振电路,并因负阻尼效应引起系统的次同步振荡;最后仿真验证理论分析的正确性。
Double fed induction generator(DFIG)-based wind farm integration through voltage source converter based HVDC(VSC-HVDC)system will be a potential mode for deliveringlarge-scale wind power in the"Three-North Regions"of China.However,the interaction between DFIG and VSC-HVDC system may cause the risk of subsynchronous oscillation(SSO).For understanding the mechanism of the risk,the equivalent system model of multiple DFIGs connected to VSC-HVDC system was established.And on this basis,the impedance analytical method was adopted to explore the mechanism of SSO.Moreover,the impact of factors such as online numbers of DFIGs,wind speed and loading level on its characteristics were analyzed.Sensitivity indicators were introduced to analyze the impact of PI controllers'parameters on the system impedance.The theoretical analysis show that there indeed exist SSO phenomena at a certain operation condition.DFIGs behave as an inductive reactance with a negative resistance at resonance point,whose interaction with wind farm VSC(WFVSC)(consider asa resistancecapacitance)constitutes the equivalent resonance circuit with negative resistance.Therefore,the power oscillation tends to appear due to the negative damping.Finally,the correctness of the theoretical analysis was verified by time-domain simulation.
作者
孙焜
姚伟
文劲宇
SUN Kun;YAO Wei;WEN Jinyu(State Key Laboratory of Advanced Electromagnetic Engineering and Technology(School of Electric and Electronic Engineering,Huazhong University of Science and Technology),Wuhan430074,Hubei Province,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2018年第22期6520-6532,共13页
Proceedings of the CSEE
基金
国家自然科学基金项目(51577075)~~
关键词
双馈风机
柔性直流
次同步振荡
阻抗分析法
振荡特性
double fed induction generator(DFIG)
voltage source converterbased HVDC(VSC-HVDC)
subsynchronous oscillation(SSO)
impedance analytical method
oscillation characteristics
