适用于架空线柔直的嵌套式全桥型混合MMC方案  

The Embedded Full-bridge Type Hybrid MMC Suitable for Overhead Line VSC-HVDC Transmission System

作　　者：丁江萍[1] 吕煜 赵西贝 许建中[1] 郭春义[1] 赵成勇[1] DING Jiangping;LÜYu;ZHAO Xibei;XU Jianzhong;GUO Chunyi;ZHAO Chengyong(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,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)

出　　处：《中国电机工程学报》2019年第23期6844-6851,共8页Proceedings of the CSEE

基　　金：国家电网公司总部科技项目资助(±800kV特高压柔性直流输电换流阀和控制保护关键技术研究)~~

摘　　要：应用全桥子模块的负电平输出能力,基于子模块混合型模块化多电平换流器(modular multilevel converter,MMC)的柔性直流输电系统可以有效清除直流故障,但全桥子模块在投资成本和稳态损耗上均需作出较大牺牲。该文提出一种基于嵌套式全桥阀段的混合MMC方案,该阀段的拓扑结构使其具备整体输出负电平能力,同时阐述直流故障无闭锁穿越控制理论,在发生直流侧故障时无需闭锁MMC,且能在故障期间对交流系统提供无功支撑。以一个简单仿真电路说明嵌套式全桥阀段的工作原理,并在典型的双端柔直系统中仿真验证其故障清除能力。最后从成本、占地、运行损耗3个方面对EFB-MMC的经济性进行分析,结果表明,其相比于传统半–全混合MMC更具备经济性优势,应用于架空线柔性直流输电系统中具有一定的前景。Applying the negative-level output capability of the full-bridge sub-module(FBSM),the flexible HVDC system based on the semi-full cell hybrid modular multilevel converter(MMC)can effectively eliminate DC faults,but the implementation of full-bridge sub-module needs to make greater sacrifices in both investment cost and steady-state loss.In this paper,a hybrid MMC scheme based on embedded full-bridge(EFB)valve section was proposed.The valve segment has the overall output negative level capability.At the same time,the theory of non-blocking ride-through control in overhead flexible DC transmission system was described.No blocking of MMC valve was required in the event of DC-side fault,and could provide reactive power support to the AC system during the fault.The operation principle of the embedded full-bridge valve segment was illustrated by a simple simulation circuit,and its fault clearing capability was verified by simulation in a typical double terminal HVDC system.Finally,the technical and economic performance of EFB-MMC was analyzed from three aspects of cost,footprint requirements and operating loss.The results show that it has more economic advantages than traditional semi-full cell hybrid MMC.This scheme has certain prospects for use in overhead line flexible DC transmission systems.

关 键 词：嵌套式全桥 子模块混合型模块化多电平换流器 柔性直流输电 直流故障 

分 类 号：TM46[电气工程—电器]