弱电网中低电压穿越控制策略导致的双馈风机失稳机理分析  

Analysis of LVRT control strategy-oriented DFIG instability mechanism in weak grid

作　　者：袁辉 宋晓喆 孙福寿 辛焕海[1] 黄林彬[1] 宫泽旭 YUAN Hui;SONG Xiaozhe;SUN Fushou;XIN Huanhai;HUANG Linbin;GONG Zexu(College of Electrical Engineering,Zhejiang University,Hangzhou 310027,China;State Grid Jilin Electric Power Co.,Ltd.,Changchun 130021,China)

机构地区：[1]浙江大学电气工程学院,浙江杭州310027 [2]国网吉林省电力有限公司,吉林长春130021

出　　处：《电力自动化设备》2020年第9期50-56,共7页Electric Power Automation Equipment

基　　金：国网吉林省电力有限公司2019年科技项目(双馈风机与SVG交互作用下的系统振荡机理与控制方法研究)(2019-35)。

摘　　要：弱电网中当远端发生严重电压跌落故障时,低电压穿越(LVRT)控制策略可能会导致双馈风机并网系统出现稳定问题。为此,首先建立了故障期间系统的准稳态模型,基于相平面法揭示了因平衡点不存在导致的系统大干扰失稳机理,并分析了电压跌落程度、线路阻抗幅值和相角以及无功电流控制增益系数等关键影响因素。然后,建立了LVRT期间系统的小信号模型,并分析了LVRT控制策略中转子电流参考值动态对系统小干扰稳定的影响。研究表明,忽略转子电流参考值动态会导致小干扰稳定分析结果偏乐观。LVRT(Low-Voltage Ride-Through)control strategy may cause stability problems of DFIG(Doubly-Fed Induction Generator)connected system when serious voltage drop fault occurs at the remote end in weak grid.Therefore,firstly the quasi-steady state model of DFIG during fault is derived,and the large dis⁃turbance instability mechanism caused by the absence of equilibrium point is explained according to phaseplane method.Moreover,the key influencing factors such as the degree of voltage sag,amplitude and phase of grid impedance and gain of reactive current control are analyzed.Secondly,the system’s small signal model during LVRT is derived,and the effects of rotor current reference’s dynamics on small disturbance stability in LVRT control strategy are studied.The analysis result shows that omitting the rotor current reference’s dynamics may cause the analyzing results optimistical.

关 键 词：双馈风机 弱电网 准稳态模型 小信号建模 低电压穿越 

分 类 号：TM614[电气工程—电力系统及自动化] TM712