| 引用本文: | 贾科,姚昆鹏,刘子奕,刘可歆,张恬昕,毕天姝.基于模量行波差异的柔性直流输电线路单端量保护方法[J].电力自动化设备,2023,43(10):112-120 |
| JIA Ke,YAO Kunpeng,LIU Ziyi,LIU Kexin,ZHANG Tianxin,BI Tianshu.Non-unit protection method for flexible DC transmission line based on traveling wave difference of mode component[J].Electric Power Automation Equipment,2023,43(10):112-120 |
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| 摘要: |
| 在柔性直流输电中，基于波形特征的行波保护在近端或对近端故障时易受后续行波影响，保护范围存在死区；且发生区外非金属性故障时故障处电压并非阶跃波，若以故障处电压为阶跃波开展原理研究，则也会影响保护的动作性能。针对以上问题，首先解析发生区内、外故障时故障处电压波形差异的原因，然后分析线模与零模电流之间的差异性，进一步得到反映区内、外故障的模量行波差异通项。为避免区外非金属性故障的影响，在此基础上利用不对称故障下行波的折反射特征，提出模量行波差异与折反射特征相配合的单端量保护方法。PSCAD/EMTDC的仿真结果表明，所提保护方法能有效解决近端故障下保护拒动的问题且具有较强的耐受过渡电阻能力和抗噪声干扰能力，此外还避免了区外非金属故障的影响。 |
| 关键词: 柔性直流输电 继电保护 故障处电压 模量行波差异 折反射特征 单端量保护 |
| DOI：10.16081/j.epae.202309014 |
| 分类号:TM77 |
| 基金项目:国家自然科学基金资助项目(52277097) |
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| Non-unit protection method for flexible DC transmission line based on traveling wave difference of mode component |
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JIA Ke, YAO Kunpeng, LIU Ziyi, LIU Kexin, ZHANG Tianxin, BI Tianshu
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State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
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| Abstract: |
| In flexible DC transmission, line traveling wave(TW) protection based on waveform characteristics is vulnerable to subsequent TWs during proximal or contralateral proximal faults, and the protection range has dead zone. In addition, the voltage waveform at the fault point is not a step waveform in case of external non-metallic faults, if the principle study is carried out with the voltage at the fault point as a step wave, the operation performance of the protection will be affected. To address the issues mentioned above, the reason for the difference in the voltage waveform at the fault point in case of internal or external fault is analyzed. Then the difference between line-and zero-mode currents is analyzed to obtain the general term of TW difference of mode component. In order to avoid the influence of external non-metallic fault, based on the TW inter-refraction characteristic under asymmetric faults, a non-unit protection method combines traveling wave difference of mode component and inter-refraction characteristic is proposed. The simulative results of PSCAD/EMTDC show that the proposed protection can effectively solve the problem of protection rejection under proximal faults and has a strong ability to withstand transition resistance and anti-noise interference. Moreover, the impact of the waveform in case of external non-metallic fault can be avoided. |
| Key words: flexible DC transmission relay protection voltage at fault point traveling wave difference of mode component characteristic of inter-refraction non-unit protection |
