| 引用本文: | 邢亚辉,王海军,吕艳萍.基于线路零序频率特性的小电流接地系统故障选线[J].电力自动化设备,2006,(4):59-62 |
| .Faulty line selection in non-solid earthed network based on zero sequence frequency characteristic of transmission lines[J].Electric Power Automation Equipment,2006,(4):59-62 |
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| 摘要: |
| 根据均匀传输线路的频率特性,对于空载线路,当频率小于fm时,线路输入阻抗呈容性,线路可用一集中电容等效。小电流接地系统发生单相接地故障时,对零序分量而言,非故障线路相当于空载。根据这一特点,对小电流接地系统中线路的零序参数相频特性进行研究,得出系统发生单相接地故障时不同频带上暂态零序电流特性。在选定频带SFB(SelectedFrequencyBand)内,非故障线路零序电流极性和故障线路相反。应用小波包对各线路的暂态零序电流进行分解,小波包系数的符号代表了相应频带零序电流的极性,通过比较SFB内小波包系数的符号,便可找出故障线路。EMTDC仿真试验结果表明该方法可以准确地实现单相故障选线,并验证了文章对输电线路零序输入阻抗相频特性分析的正确性。 |
| 关键词: 小电流接地系统,单相故障,小波包分析,相频特性,暂态零序电流,极性 |
| DOI： |
| 分类号:TM773 |
| 基金项目: |
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| Faulty line selection in non-solid earthed network based on zero sequence frequency characteristic of transmission lines |
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XING Ya-hui WANG Hai-jun L(U) Yan-ping
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| Abstract: |
| According to the frequency characteristic of an even transmission line,when the frequency is lower than fm,the input impedance of an unloaded even transmission line is capacitive,and the line maybe modeled as a capacitor.The healthy line is unloaded for zero-sequence component when a single-phase fault occurs in a non-solid earthed network.The zero-sequence angle-frequency characteristic of the lines are studied based on it and the characteristics of transient zero-sequence current in different frequency bands when a single-phase fault occurs in a non-solid earthed network are found.In SFB(Selected Frequency Band),the polarity of transient zero-sequence current in faulty line is opposite to that in healthy ones.The wavelet packet is used to decompose transient zero-sequence current and the coefficients represent the polarity of the current.Comparison of coefficient signs can find out the faulty line.The EMTDC simulations indicate that the method can find out the faulty line correctly and prove that the analysis of the angle-frequency characteristic of zero impedance of the line is correct. |
| Key words: non-solid earthed network,single phase faults,wavelet packet analysis,angle-frequency characteristics,transient zero-sequence current,polarity |
