直驱风电场多电压源型变流器控制耦合引发振荡的机理分析  

Mechanism Analysis of Oscillations Induced by Control Coupling of Voltage Source Converters in Wind Farms with Direct-driven Turbines

作　　者：郑泽天 沈沉[1] 严鋆 袁沐琛 刘晔 范辉 ZHENG Zetian;SHEN Chen;YAN Jun;YUAN Muchen;LIU Ye;FAN Hui(Department of Electrical Engineering,Tsinghua University,Beijing 100084,China;China Electric Power Research Institute,Beijing 100092,China;State Grid Hebei Electric Power Co.,Ltd.,Shijiazhuang 050022,China)

机构地区：[1]清华大学电机工程与应用电子技术系,北京市100084 [2]中国电力科学研究院有限公司,北京市100192 [3]国网河北省电力有限公司,河北省石家庄市050022

出　　处：《电力系统自动化》2023年第17期14-26,共13页Automation of Electric Power Systems

基　　金：国家电网有限公司科技项目(5100-202255002A-1-1-ZN)。

摘　　要：近年来,直驱风机风电场相关的电力系统电磁振荡现象已成为研究热点。文中对风电场中多台静止无功发生器(SVG)之间的耦合振荡机理以及由此引发风电场自持振荡的可能性进行了研究。考虑到直驱风机和风电场出口SVG同属电压源型变流器(VSC),在控制结构上具有相似性,提出了定电压控制模式下双VSC耦合系统产生不稳定模式的机理及其电压参考值匹配判据,对运行方式发生变化(体现为与系统的连接电抗发生变化)导致发散振荡的概率给出了计算方法。结合算例分析和讨论可知,当定电压控制的2台SVG电气距离较近时,如不满足电压参考值匹配判据则系统存在不稳定模式。通过计算连接电抗大小变化时主导特征根实部的分布函数可知,该模式与连接电抗变化情况弱相关,与SVG控制模式强相关,且可能成为风电场内直驱风机非线性限幅自持振荡的激发条件。In recent years,electromagnetic oscillation in power systems related to wind farms with direct-driven wind turbines has become a hot research topic.This paper studies the coupling oscillation mechanism among multiple static var generators(SVGs)in wind farms and the possibility of self-sustaining oscillation in wind farms caused by coupling oscillation.Considering that both direct-driven wind turbines and SVGs at the terminal of wind farms are both voltage source converters(VSCs)and have similar control structure,this paper proposes the mechanism for the unstable mode generated by double-VSC coupling systems under the constant voltage control mode and the corresponding voltage reference matching criteria.The probability of diverging oscillation induced by changes in operation modes(reflected as changes in the connection reactance to the system)is also calculated.Through the case analysis and discussion,it is concluded that the system will have an unstable mode if the voltage reference matching criteria are not met when the electrical distance between the two SVGs under constant voltage control is close.By calculating the distribution function of the real part of dominant eigenvalues when the connection reactance changes,it is concluded that the mode is weakly correlated with the connection reactance changes but strongly correlated with the SVG control mode.Furthermore,it may become the excitation condition for the nonlinear limiting self-sustaining oscillation in wind farms with direct-driven wind turbines.

关 键 词：电磁振荡 直驱风机 静止无功发生器 电压源型变流器 耦合振荡 自持振荡 

分 类 号：TM614[电气工程—电力系统及自动化] TM712