基于无功功率注入的MMC-HVDC交流电网等值阻抗识别方法  

Identification Method for Equivalent Impedance of AC Power Grid Connected to MMC-HVDC System Based on Reactive Power Injection

作　　者：郝晓宇 郭春义 蒋雯 彭茂兰 林欣 HAO Xiaoyu;GUO Chunyi;JIANG Wen;PENG Maolan;LIN Xin(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University),Beijing 102206,China;Maintenance and Test Center,EHV Power Transmission Company of China Southern Power Grid Co.,Ltd.,Guangzhou 510663,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京市102206 [2]中国南方电网有限责任公司超高压输电公司检修试验中心,广东省广州市510663

出　　处：《电力系统自动化》2023年第9期184-192,共9页Automation of Electric Power Systems

基　　金：国家自然科学基金资助项目(51877077)。

摘　　要：交流电网等值阻抗反映了交流系统的强度,系统强度降低会给模块化多电平换流器型高压直流(MMC-HVDC)输电系统的稳定运行带来不利影响。为规避高阻抗/低强度给交直流系统带来的安全运行风险,实现复杂多变电网等值阻抗的迅速准确检测,文中以包含双端模块化多电平换流器的交直流系统为研究对象,提出了一种基于无功功率扰动注入的交流电网等值阻抗在线识别方法。首先,从理论角度介绍了无功扰动注入的阻抗识别原理,分析了交流电网电阻大小以及测量表计误差对阻抗识别精度的影响,构建了基于交流母线电压信息的阻抗识别精度评价指标。然后,基于此指标提出了无功功率扰动注入量的设计原则以及基于识别精度约束的交流电网等值阻抗在线识别方法。最后,通过仿真进行验证,证明了所提方法的可行性以及阻抗识别精度的可控性。The equivalent impedance of the AC power grid reflects the strength of the AC system,and the reduction of the system strength will adversely affect the stable operation of the modular multilevel converter based high voltage direct current(MMCHVDC)transmission system.In order to effectively avoid the safe operation risk of the AC/DC systems brought by high impedance/low strength and realize the rapid and accurate detection of the equivalent impedance of complex and changeable power grids,this paper proposes an online identification method of the equivalent impedance based on reactive power disturbance injection for the AC power grid with modular multilevel converters at both ends.First,the principle of impedance identification with reactive power injection is described from the theoretical perspective,and the influence of the resistance and measurement meter error on the impedance identification accuracy is analyzed.Then,an evaluation index for impedance identification accuracy based on AC bus voltage information is established.Based on this index,this paper proposes the principle to design the volume of reactive power disturbance injection and the online identification method for the equivalent impedance of the AC power grid based on the identification accuracy constraint.Finally,the feasibility of the proposed method and the controllability of the impedance identification accuracy are verified by simulation.

关 键 词：柔性直流输电 交流系统 无功功率注入 阻抗识别 精度评价 精度约束 

分 类 号：TM721.1[电气工程—电力系统及自动化]