LCC-MMC混合直流输电系统直流回路谐振特性研究  

Research on the Resonance Characteristics of the DC Loop of the LCC-MMCHybrid DC Transmission System

作　　者：王彤彤 文俊[1] 靳海强 韩民晓[1] WANG Tongtong;WEN Jun;JIN Haiqiang;HAN Minxiao(School of Electrical&Electronic Engineering,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学电气与电子工程学院,北京102206

出　　处：《电网与清洁能源》2021年第3期1-7,16,共8页Power System and Clean Energy

基　　金：国家重点研发计划项目(2016YFB0900604)。

摘　　要：针对一种在整流侧和逆变侧分别采用电网换相型换流器(LCC)和模块化多电平换流器(MMC)的新型混合直流输电系统,提出了直流回路的谐波模型。在整流侧采用三脉动谐波电压源,等效了12脉动换流器的谐波输出特性;在逆变侧使用电容串联电感的无源结构作为MMC直流侧等效电路,同时搭建了输电线路及直流滤波器相应的谐波模型。以单极混合直流输电系统为例,对该直流回路进行阻抗-频率扫描,计算出不同情况下该直流回路的谐波阻抗大小,从而对谐振情况进行判断。仿真结果表明:随着线路长度及滤波器组数的增加,谐振频率均有所降低。Aiming at a hybrid DC transmission system that uses LCC at the rectifier side and the MMC at the inverter side respectively,the harmonic characteristics of both LCC and MMC are proposed.First,the LCC at the rectifier side is replaced by the 3-pulse harmonic voltage source,whose harmonic output characteristics is equivalent to a 12-pulse converter.Second,the MMC is represented by a passive electric network.At the same time,the corresponding harmonic models of DC transmission lines and DC filters are constructed.Finally,taking the single-pole hybrid DC transmission system as an example,through scanning the impedance-frequency result of the DC loop,the harmonic impedance under different conditions is calculated to judge the resonance situation.The simulation results show that as the line length and the number of filters increases,the resonance frequency decreases.

关 键 词：混合直流输电 电网换相换流器 模块化多电平换流器 三脉动谐波电压源 谐振特性 

分 类 号：TM714[电气工程—电力系统及自动化]