| 引用本文: | 薛英林,徐 政,张哲任,刘高任.子模块故障下C -MMC型高压直流系统的保护设计和容错控制[J].电力自动化设备,2014,34(8): |
| XUE Yinglin,XU Zheng,ZHANG Zheren,LIU Gaoren.Protection design and fault-tolerant control of C-MMC based HVDC system under sub-module failure condition[J].Electric Power Automation Equipment,2014,34(8): |
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| 摘要: |
| 从子模块级、换流器级和系统级3个层次上设计了基于箝位双子模块（CDSM）的新型模块化多电平换流器（MMC）的冗余保护控制策略。提出了基于双晶闸管保护策略，其中一个晶闸管稳态长期导通来分担二极管电流以减少损耗，并分析了子模块的失效机制。设计了改进型最近电平调制和电容电压平衡策略。该方法动态调节电容电压参考值，通过引入故障因子对电容电压测量值进行修正以防止故障元件参与投切。利用3次谐波注入调制、变压器分接头档位控制和有功无功调节等手段，优化提高动态备用子模块数目和增强系统不间断功率运行能力。在PSCAD／EMTDC中搭建每桥臂105个子模块的仿真模型，仿真结果表明：引入双晶闸管保护策略后，整流侧和逆变侧二极管总损耗分别下降9.8 % 和5.3 %；即使36个模块电容切除后，系统仍可正常运行，且换流器桥臂环流的增量不超过额定值的5 %。 |
| 关键词: 模块化多电平换流器 高压直流输电 箝位双子模块 子模块故障 容错 双晶闸管 动态备用 故障因子 |
| DOI： |
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| 基金项目:基金项目：国家高技术研究发展计划（863计划）项目（2012AA-050205） |
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| Protection design and fault-tolerant control of C-MMC based HVDC system under sub-module failure condition |
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XUE Yinglin, XU Zheng, ZHANG Zheren, LIU Gaoren
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College of Electrical Engineering，Zhejiang University，Hangzhou 310027，China
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| Abstract: |
| A strategy of redundant protection and control is designed for the CDSM（Clamp Double Sub-Module） based MMC（Modular Multilevel Converter） in three levels of SM（Sub-Module），converter and system. A protection scheme based on dual thyristors is proposed，one of which is always conductive to share the diode current for loss deduction. The SM failure mechanism is analyzed and an improved strategy of the nearest level modulation and capacitor voltage balancing is proposed. The capacitor voltage reference is dynamically adjusted and a fault factor is applied to modify the measured capacitor voltage for preventing the faulty element from switching over. Multiple measures，such as the third-order harmonic injection modulation，transformer tap control，power regulation，etc.，are used to increase the dynamic spare SMs and strengthen the system ability of non-interrupted operation. A simulation model with 105 SMs per arm is built with PSCAD／EMTDC software and the simulative results show that，with the dual-thyristor protection scheme，the diode loss deduction of rectifier is 9.8 % and that of inverter 5.3 %；the system works well even when 36 module capacitors are removed，with the increase of converter arm circulating current less than 5 % of the rated value. |
| Key words: modular multilevel converter HVDC power transmission clamp double submodule sub-module failure fault tolerance dual-thyristor dynamic spare fault factor |
