基于MMC的多端直流输电系统阻抗频率特性研究  

Impedance-Frequency Characteristic of MMC-MTDC System

作　　者：田亦凡[1] 许冬[2] 韩民晓[1] 郑超[3] TIAN Yifan XU Dong HAN Minxiao ZHENG Chao(School of Electric and Electronic Engineering, North China Electric Power University, Beijing 102206, China State Power Economic Research Institute, Beijing 102209,China China Electric Power Research Institute, Beijing 100192, China)

机构地区：[1]华北电力大学电气与电子工程学院,北京市102206 [2]国网北京经济技术研究院,北京市102209 [3]中国电力科学研究院,北京市100192

出　　处：《电力建设》2017年第8期118-122,共5页Electric Power Construction

基　　金：国家电网公司科技项目(XT71-16-030)

摘　　要：文章研究了基于模块化多电平换流器的多端直流输电(modular multilevel converter-multi-terminal direct current,M M C-M TDC)系统在交流系统背景谐波作用下的频率响应特性。首先,分析了基于M M C的多端直流输电系统的阻抗频率特性,说明交流背景谐波引起直流网络谐振的原因。其次,分析了平波电抗器的电感值大小与基于M M C的多端直流输电系统的谐振频率之间的关系,可作为合理选择平波电抗器的依据,以避免直流网络在交流谐波互补频率处发生谐振。最后,通过在PSCAD中搭建基于MMC的4端直流输电系统仿真模型,验证了理论分析结果以及直流网络谐振频率和平波电感之间的关系。仿真结果验证了理论分析的正确性,并表明可以通过调节平波电感值来改变直流网络的谐振频率,以避免交流系统背景谐波引起直流网络的谐振。This paper investigates the frequency response characteristics of modular multilevel converter-multi-terminal direct current （MMC-MTDC） system under AC background harmonics. Firstly, we analyze the frequency-impedance characteristics of MMC-MTDC system to illustrate the reason of the DC network resonance caused by AC background harmonics. Secondly, we analyze the relation between the inductance value of smoothing reactor and the resonant frequency of MMC-MTDC system, which can be used as the basis for the reasonable selection of smoothing reactor to avoid the resonance of the DC network at AC harmonic complementary frequency. Finally, the analytical results and the relationship between resonant frequency of DC network and smoothing reactor are verified by the simulation model of a 4-terminal MMC- MTDC in PSCAD. The simulation results validate the correctness the theoretical analysis, and confirm that the resonant frequency of DC network can be changed by adjusting the inductance value of smoothing reactor, in order to avoid the resonance of the DC network caused by AC harmonic complementary frequency.

关 键 词：背景谐波 模块化多电平换流器(MMC) 多端直流输电(MTDC) 谐振 阻抗频率特性 

分 类 号：TM72[电气工程—电力系统及自动化]