| 引用本文: | 高淑萍,胡振宇,张保会,宋国兵.一种适用于MMC-HVDC直流输电线路的保护新原理[J].电力系统保护与控制,2018,46(13):13-20.[点击复制] |
| GAO Shuping,HU Zhenyu,ZHANG Baohui,SONG Guobing.A new relay protection principle of MMC-HVDC transmission lines[J].Power System Protection and Control,2018,46(13):13-20[点击复制] |
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| 摘要: |
| 模块化多电平换流器(Modular Multilevel Converter, MMC)作为一种新型多电平拓扑结构的电压源换流器，具有扩展性强、输出电压质量高、谐波含量少等优点，已经展现出极其重要的工程应用前景。首先介绍了模块化多电平高压直流输电(Modular Multilevel Converter based High Voltage Direct Current, MMC-HVDC)的拓扑结构及运行原理，然后通过故障附加状态网络分别对区内和区外故障进行了分析，并利用二阶微分法提取了故障时电压、电流的故障分量，得出了保护策略。根据故障网络分析可知，当直流线路发生区内故障时，电流故障分量极性相同；当直流线路发生区外故障时，电流故障分量极性相反。因此，可以根据电流故障分量的极性是否相同来识别区内、外故障，利用二阶微分法来提取故障时电流的故障分量，用以识别区内、外故障。另外，根据故障网络分析还发现，当直流线路发生区内故障时，单极故障时电压故障分量极性相同，双极故障时电压故障分量极性相反。因此，可以根据电压故障分量的极性是否相同来识别故障极。利用二阶微分法来提取故障时电压的故障分量，根据电压故障分量的极性，识别故障所在的极。最后利用PSCAD电磁暂态仿真软件建立了MMC-HVDC的仿真模型。仿真结果验证了故障分析以及保护方法的正确性。 |
| 关键词: MMC-HVDC 故障分析 二阶微分法 继电保护 PSCAD |
| DOI：10.7667/PSPC171429 |
| 投稿时间：2017-09-24修订日期：2017-12-13 |
| 基金项目:国家自然科学基金联合基金重点支持项目(U1766209)和国家自然科学基金面上项目(No.51777166) |
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| A new relay protection principle of MMC-HVDC transmission lines |
| GAO Shuping,HU Zhenyu,ZHANG Baohui,SONG Guobing |
| (Xi’an University of Science and Technology, Xi’an 710054, China;Xi’an Jiaotong University, Xi’an 710049, China) |
| Abstract: |
| As a new type of voltage source multilevel converters, the Modular Multilevel Converter (MMC) has strong expansibility, high output voltage quality, low harmonic content, and it has shown the great prospect of application. This paper firstly introduces the topology structure and operation principle of MMC-HVDC. Then, the internal and external faults are analyzed respectively through the fault added state network, and a protection strategy is given by extracting the fault component of current and voltage fault component by two-order differential method. According to the fault network analysis, when the fault occurs in the DC line, the polarity of the current fault component is the same. When the fault occurs outside the DC line, the polarity of the current fault component is opposite. Therefore, the internal and external faults can be identified according to whether the polarity of the current fault component is identical by extracting the current fault component with two derivative identification. In addition, according to the fault network analysis, when the internal fault occurs in the DC line, voltage fault component has the same polarity while unipolar fault occurs in the DC lines, and voltage fault component has opposite polarity while bipolar fault occurs in the DC lines. Therefore, according to the polarity of the voltage fault component, it can recognize fault polarity and extract the voltage fault component by two-order differential method to identify fault polarity. Finally, simulation model of MMC-HVDC is established in PSCAD. Simulation results are given to verify the correctness of the fault analysis and protection methods. This work is supported by Key Support Projects of National Natural Science Foundation of China (No. U1766209) and National Natural Science Foundation of China (No. 51777166). |
| Key words: MMC-HVDC fault analysis two-order differential method relay protection PSCAD |
