两级式光伏系统序阻抗建模与并网稳定性分析  

Two-stage photovoltaic system sequence impedance modeling and grid-connected stability analysis

作　　者：徐群伟 朱非白 潘星 熊鸿韬 庄凯勋 孙建军[2,3] XU Qunwei;ZHU Feibai;PAN Xing;XIONG Hongtao;CHUANG Kaihsun;SUN Jianjun(Electric Power Science Research Institute,State Grid Zhejiang Electric Power Co.,Ltd.,Hangzhou 310014,China;School of Electrical Engineering and Automation,Wuhan University,Wuhan 430072,China;Hubei Key Laboratory of Power Equipment&System Security for Integrated Energy,Wuhan University,Wuhan 430072,China)

机构地区：[1]国网浙江省电力有限公司电力科学研究院,浙江杭州310014 [2]武汉大学电气与自动化学院,湖北武汉430072 [3]武汉大学综合能源电力装备及系统安全湖北省重点实验室,湖北武汉430072

出　　处：《武汉大学学报（工学版）》2024年第10期1449-1458,共10页Engineering Journal of Wuhan University

基　　金：国网浙江省电力有限公司科技项目(编号:5211DS22000F)。

摘　　要：大规模分布式光伏系统接入对电网的稳定运行造成一定影响。现有用于稳定性分析的数学模型多忽略光伏并网系统直流侧动态过程的影响,尤其鲜少提及两级式光伏并网系统的前级结构及控制对系统造成的失稳。为此,提出基于谐波线性化的计及两级式光伏并网系统前级动态过程的序阻抗建模方法。首先,对两级式光伏并网系统前、后级协同控制策略进行阐述。然后,对两级式光伏系统的前、后级分别进行序阻抗建模,根据两者之间的数学关系得到完整的序阻抗模型,并结合仿真实验对所建立的序阻抗模型进行扫频验证。最后,基于所提出的序阻抗模型,研究两级式光伏系统的并网稳定性,与现有阻抗模型相比,其在稳定性分析方面更具优势。仿真实验表明,所建立序阻抗模型能够更加真实地反映系统交流端口阻抗特性,在稳定性分析中具有良好的效果。The large-scale distributed photovoltaic(PV)system's integration has a certain impact on the stable operation of power grid.Most of the existing mathematical models used for stability analysis overlook the influence of the dynamic process on the direct current side of the PV grid-connected system,especially the instability caused by the front-end structure and control of the two-stage PV grid-connected system.Therefore,this paper proposes a sequential impedance modeling method based on harmonic linearization,which takes into account the dynamic process of the front end of the two-stage PV grid-connected system.Firstly,this paper elaborates on the coordinated control strategy of the front and rear stages of the two-stage PV grid-connected system.Secondly,this paper models the sequential impedance of the front and rear stages of the two-stage PV system respectively.A complete sequential impedance model is obtained according to the mathematical relationship between the two,and the sequence impedance model is verified by sweeping frequency in combination with simulation experiment.Finally,based on the proposed sequential impedance model,the gridconnected stability of the two-stage PV system is studied.Compared with the existing impedance models,it has more advantages in stability analysis.Simulation experiments show that the established sequential impedance model can truly reflect the system's alternating current port impedance characteristics,and has a good effect in stability analysis.

关 键 词：两级式光伏系统 谐波线性化 序阻抗模型 宽频段 

分 类 号：TM615[电气工程—电力系统及自动化]