下垂控制对直流电网动态电压稳定性的影响分析  

Influence of droop control on the dynamic voltage stability of DC grid analysis

作　　者：吴蒙 贺之渊 阎发友 吴亚楠 杨杰 周啸 WU Meng;HE Zhiyuan;YAN Fayou;WU Yanan;YANG Jie;ZHOU Xiao(State Grid Liaoning Electric Power Company Limited Electric Power Research Institute,Shenyang 110006,China;Global Energy Interconnection Research Institute Co.Ltd,Beijing 102200,China;CET-College of Engineering and Technology,Southwest University,Chongqing 400715,China)

机构地区：[1]国网辽宁省电力有限公司电力科学研究院,辽宁沈阳110006 [2]全球能源互联网研究院有限公司,北京102200 [3]西南大学工程技术学院,重庆400715

出　　处：《电力系统保护与控制》2019年第10期8-15,共8页Power System Protection and Control

基　　金：国家重点研发计划资助(2016YFB0900900);西南大学博士科研启动基金项目资助(SWU118053)~~

摘　　要：直流电网的协调控制策略包括主从控制、直流电压裕度控制及直流电压下垂控制等。下垂控制可以实现直流电网的多点直流电压控制,但下垂系数的大小会对系统直流侧电压的稳定性产生一定的影响。以基于模块化多电平换流器(Modular Multilevel Converter, MMC)的直流电网为研究对象,首先建立了下垂控制作用下MMC直流电压控制系统模型及其传递函数,并在此基础上,采用劳斯判据得到了能够保持系统直流电压稳定的下垂系数取值范围。然后,分别在时域和频域中分析了在不同取值区间内选取下垂系数对系统直流侧电压控制特性和稳定性的影响。最后,在PSCAD/EMTDC中建立了基于MMC的4端直流电网仿真模型,验证了理论分析的正确性,为工程应用时合理选择下垂系数提供了理论依据。Coordinating control strategies of DC grids include master slave control,voltage margin control and voltage droop control,etc.Droop control could achieve distributed voltage control of DC grid,but the droop coefficients would influence the stability of the system.A Modular Multilevel Converters(MMCs)based DC grid is investigated.First,the mathematical model of the MMCs with droop control and its transfer functions are derived.Then,a reasonable value range of droop coefficients that would maintain the system stability is presented by the Routh criterion.The influences of selection of droop coefficients in different ranges on voltage stability are analyzed in time domain and frequency domain respectively.Finally,a four-terminal MMCs based DC grid model is established in PSCAD/EMTDC.The simulation results verify the correctness of the theoretical analysis,and the analysis method will provide a theoretical basis of droop coefficients selection for DC grid applications.

关 键 词：直流电网 模块化多电平换流器 下垂控制 电压稳定性 

分 类 号：TM721.1[电气工程—电力系统及自动化]