电网电压不对称时MMC-HVDC精确环流抑制控制  

MMC-HVDC precise circulation suppression control under asymmetrical network voltage

作　　者：张磊 范彩云 韩坤 张志刚 司志磊 ZHANG Lei;FAN Caiyun;HAN Kun;ZHANG Zhigang;SI Zhilei(XJ Electric Co., Ltd., Xuchang 461000, China)

机构地区：[1]许继电气股份有限公司,河南许昌461000

出　　处：《电力系统保护与控制》2018年第12期42-49,共8页Power System Protection and Control

基　　金：国家02专项--基于国产IGBT的电网装备研制及试验平台建设(2015ZX02301003)~~

摘　　要：基于模块化多电平换流器(MMC)柔性直流输电被认为是最具竞争力的高压直流输电方式。基于PR控制器的MMC环流抑制策略已经得到广泛应用并能有效降低桥臂各环流分量,但在电网电压不对称时,桥臂环流中零序电流分量将进入直流侧引起直流电压/电流2倍频波动,现有控制策略不能很好地对其进行抑制。并且现有环流控制模型不能完全揭示MMC内部固有特性,这也阻碍了对MMC的进一步的理解和应用。针对以上两个问题,提出精确的环流控制模型,指出MMC内部环流电气量之间的相互关系。在此基础上,设计了新的环流抑制策略,在Matlab中搭建了±100 k V/300 MW MMC-HVDC仿真模型。仿真结果表明所提控制策略能同时降低桥臂环流和直流电压纹波,提高了MMC-HVDC故障穿越能力。Modular Multi-level Converter（MMC） Flexible DC transmission is considered to be the most competitive HVDC mode. MMC circulation suppression strategy based on the PR controller has been widely used and can effectively reduce the circulation component of bridge arm. However, when the grid voltage is not symmetrical, the zero-sequence current component in the bridge arm current will enter the DC side to cause the DC voltage/current 2 times frequency fluctuation, and the existing control strategy can not suppress it well. And the existing loop control model can not fully reveal the inherent characteristics of MMC, which also hinders the further understanding and application of MMC. Aiming at the above two problems, an accurate circulation control model is proposed, which points out the relationship between the internal circulation electrical quantity of MMC. On this basis, a new circulation suppression strategy is designed, and a ± 100 kV/300 MW MMC-HVDC simulation model is built in Matlab. Simulation results show that the proposed control strategy can both reduce the bridge arm current and DC voltage ripple, and improve the MMC-HVDC fault ride through capability.

关 键 词：高压直流输电 模块化多电平换流器 电网电压不对称 直流电压波动 零序环流抑制 

分 类 号：TM721.1[电气工程—电力系统及自动化]