摘要
柔性直流输电技术(voltage source converter based high voltage direct current,VSC-HVDC)应用于远距离大容量架空线输电是实现我国能源资源优化配置的客观要求,也是电网技术发展的未来趋势。目前柔性直流输电技术扩展到架空线输电场合所面临的关键问题有:直流线路故障难以快速清除、输送容量难以与传统直流输电相媲拟、主接线方式和接地方式选择原则还没有定论等。针对问题1,分析现有工程所采用的拓扑结构在直流故障下的脆弱性,重点综述具有直流故障穿越能力的拓扑结构。根据其处理直流故障的特点将其划分为3种基本类型。对比分析几种典型拓扑的优缺点。针对问题2和3,为实现高电压大容量输电任务,提出基于组合式换流器的双极结构拓扑。该结构内每极由若干基本换流单元(basic converter units,BCU)串并联构成,接地极线从上下正负极结构中间引出。分析4种单元扩展的方式。综述可行的接地方式及其优缺点。最后,结合我国电网结构特点和能量流动特点,分析两种基本的柔性直流系统结构,指出其所面临的挑战和机遇。
To make the voltage source converter based high voltage direct current （VSC-HVDC） system extend to long distance bulk power overhead line transmission is the inherent requirement of energy source distribution in China and future trend of power grid development. However, the challenges associated with the state-of-the-art VSC-HVDC system mainly include： a） difficulty to handle dc fault, b） less transmission capacity compared with the traditional HVDC systems, and c） difficulty to select grounding point. For the first challenge, this paper analyzes vulnerability of the existing topologies against dc faults, focusing on an overview of the topologies with dc fault ride-through capability. According to the characteristics of dc fault processing, these topologies can be divided into three basic types. Furthermore, advantages and defects of these typical topologies are discussed. For the second and third challenges, to achieve a high voltage and power level, a bipolar VSC-HVDC topology with assembly converter is proposed. In this topology, each pole consists of several basic converter units （BCU） in series or in parallel; between the positive pole and the negative pole is the neutral bus which is connected to the ground electrode. Furthermore, the advantages and shortcomings of the possible grounding modes are summarized. At last, according to the unidirectional energy flow characteristics of China, two basic VSC-HVDC structures are analyzed.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2014年第29期5051-5062,共12页
Proceedings of the CSEE
基金
国家863高技术基金项目(2012AA050205)~~
关键词
架空线路
柔性直流输电
模块化多电平换流器
直流侧故障穿越
组合式换流器
直流侧接地
overhead line transmission
voltage sourceconverter based high voltage direct current .（VSC-HVDC）
modular multilevel converter （MMC）
DC fault ride-through
converter assembly
DC side grounding
