光伏电站与弱交流电网间次同步交互作用路径及阻尼特性分析  

Analysis of Path and Damping Characteristics of Subsynchronous Interaction Between Photovoltaic Plant and Weak AC Grid

作　　者：高本锋[1] 邓鹏程 梁纪峰 赵宇皓 Gao Benfeng;Deng Pengcheng;Liang Jifeng;Zhao Yuhao(Hebei Key Laboratory of Distributed Energy Storage and Micro-Grid North China Electric Power University,Baoding 071003 China;State Grid Hebei Electric Power Co.Ltd Electric Power Research Institute,Shijiazhuang 050021 China)

机构地区：[1]华北电力大学河北省分布式储能与微网重点实验室,保定071003 [2]国网河北省电力有限公司电力科学研究院,石家庄050021

出　　处：《电工技术学报》2023年第24期6679-6694,共16页Transactions of China Electrotechnical Society

基　　金：国家重点研发计划资助项目“响应驱动的大电网稳定性智能增强分析与控制技术”(2021YFB2400800)。

摘　　要：大规模光伏发电经长距离输电线路并入主网时,光伏电站和弱交流电网的交互作用可能使光伏并网系统面临次同步振荡(SSO)的威胁,但目前针对系统内部次同步交互作用的相关研究较少。针对上述问题,该文首先将阻尼转矩法推广到锁相环(PLL)振荡模态,并推导了光伏并网系统的线性化闭环传递函数框图。然后,基于闭环传递函数框图,揭示了PLL主导的SSO模式下系统阻尼构成和光伏电站与弱交流电网间动态交互过程。最后,借鉴等效阻尼系数量化评估了次同步交互作用的阻尼特性。结果表明,光伏并入弱交流电网系统存在PLL主导的SSO风险;光伏电站与弱交流电网的次同步交互作用向光伏并网系统提供负阻尼,是系统SSO的主导因素;增加PLL比例系数、交流电网强度、光伏电站光照强度或温度,减小PLL积分系数或光伏容量,能够增加次同步交互作用的阻尼贡献,提高光伏并网系统稳定性。时域仿真验证了理论分析结果的正确性。When a large-scale photovoltaic(PV)plant is integrated into the AC grid through long transmission lines,the interaction between the PV plant and weak AC grid may make the integration face the threat of subsynchronous oscillation(SSO).However,the mechanism of the subsynchronous interaction between the PV plant and weak AC grid are unclear,and quantifying the damping characteristics of the subsynchronous interaction is difficult by the existing analysis methods.Therefore,this paper proposes a damping torque method extended to the dynamic equation of phase-locked loop(PLL)to analyze the subsynchronous interaction between the PV plant and weak AC grid.Firstly,the damping torque method is extended to the PLL dynamic equation to analyze the stability of the PV plant integrated into the weak AC grid system in the SSO mode dominated by PLL.Secondly,the linearization model of the PV plant integration and its corresponding closed-loop transfer function block diagram are derived.Based on the closed-loop transfer function diagram,the coupling relationship and interaction path between the PV plant and weak AC grid are revealed from the perspective of internal disturbance transfer,and the dynamic process of the interaction path affecting SSO mode damping is analyzed.Thirdly,through transfer function derivation,the damping path reflecting the subsynchronous interaction is separated,and the equivalent damping coefficient is used to quantify the SSO mode damping of the subsynchronous interaction.Finally,the influences of PLL control parameters,PV capacity,AC grid strength,PV plant intensity,and temperature on the damping characteristics of subsynchronous interaction are analyzed.The mechanism analysis shows that the PV plant-weak AC grid current disturbance and the grid-side voltage disturbance drive each other at the point of common coupling,forming the subsynchronous interaction path.Then,the subsynchronous interaction path will form a closed-loop damping path through the PLL in the SSO mode dominated by PLL,affecting the syste

关 键 词：光伏电站 次同步振荡 次同步交互作用 阻尼转矩法 锁相环 

分 类 号：TM712[电气工程—电力系统及自动化]