接入弱电网的同型机直驱风电场单机等值建模  

Single Machine Equivalent Modeling of Weak Grid Connected Wind Farm with Same Type PMSGs

作　　者：李龙源[1] 付瑞清 吕晓琴[1] 王晓茹[1] 段虎昌 Li Longyuan;Fu Ruiqing;LüXiaoqin;Wang Xiaoru;Duan Huchang(School of Electrical Engineering Southwest Jiaotong University,Chengdu 611756 China)

机构地区：[1]西南交通大学电气工程学院,成都611756

出　　处：《电工技术学报》2023年第3期712-725,共14页Transactions of China Electrotechnical Society

基　　金：四川省科技计划应用基础研究重点项目资助(2020YJ0252)。

摘　　要：目前直驱风电场并弱电网稳定性研究中,风电场普遍采用单机等值,然而对于单机等值的前提条件缺少相关理论支撑。该文基于解析分析提出直驱风电场单机等值的前提条件;给出直驱风电场满足单机等值的判据;基于风电场各风机参数、出力和集电线路接线完全相同的基础假设,建立直驱风电场状态空间模型;应用矩阵相似变换理论解析分析其状态矩阵的特征根和特征向量;根据判据对单机等值进行论证。进一步地,在比基础假设更加宽泛的条件下,基于蒙特卡洛法仿真研究了同型机直驱风电场单机等值建模的有效性。为单机等值建模的应用提供了一定的理论支撑。In the current studies on stability of weak grid connected permanent magnet synchronous generator(PMSGs) wind farm, single machine equivalence is generally used for wind farm, and it is usually assumed that the wind farm is an ideal system, that is, the parameters, outputs and collector lines of all PMSGs are identical. However, there is still a lack of related theoretical support for the prerequisites of single machine equivalent modeling for PMSGs wind farm. In addition, in the actual wind farm, only the parameters of PMSGs are identical(that is, the same type), the outputs and collector lines of PMSGs are different, which is a nonideal system. Whether the single machine equivalent modeling is effective remains to be studied. In response to the problems, this paper presents the criterions for the PMSGs wind farm to meet the single machine equivalence and proposes the prerequisites of single machine equivalent modeling. It provides a certain theoretical support for the application of single machine equivalence.Firstly, three criterions are proposed to determine whether the PMSGs wind farm can be equivalent to a single machine model. There is at most one pair of critical eigenvalues in the system(i.e. weak damping or negative damping eigenvalues). The grid side state variables must participate in this oscillation mode. The critical eigenvalues of single machine equivalent model and detailed model are equal.Secondly, the oscillation characteristics and single machine equivalent modeling of the ideal system are studied analytically and theoretically. The state space model of weak grid connected PMSGs wind farm is established. The eigenvalues and eigenvectors of the state matrix are analytically analyzed using the matrix similarity transformation theory. It shows that there are one set of in-phase modes and n-1 sets of anti-phase modes in an ideal system with n PMSGs. The in-phase modes can be excited by both machine and grid sides, while the anti-phase modes can be only excited by machine sides. The weakest oscilla

关 键 词：同型机直驱风电场 弱电网 单机等值建模 前提条件 判据 

分 类 号：TM712[电气工程—电力系统及自动化]