【作者】 毛玲；

【导师】 卫志农；

【作者基本信息】 河海大学 ， 电力系统及其自动化， 2002， 硕士

【摘要】 小电流接地系统发生单相接地故障时，尽快选出故障线路，对于系统的运行是具有重要意义的。但综合国内外的研究现状，选线问题仍没有得到很好的解决。本文着重介绍了利用小波变换提取故障信号的暂态高频分量，进行故障选线的方法。 首先，文章分析了小电流接地系统，单相接地故障的暂态过程，重点分析了其中谐振接地方式的情况。在此理论基础上，提出了利用故障信号中丰富的暂态量进行选线的方法。 接着，文章利用小波变换“变焦距”的性质，对故障信号的奇异点进行分析，确定故障时刻。然后再利用小波变换的时频局部性提取故障信号中的暂态分量进行选线分析，经理论分析和算例仿真，可以发现本文提出的方法是有效、可靠的。 最后，本文利用简单的电弧模型讨论了电弧接地方式对于本文算法的影响。经算例仿真，本文的算法可以适应电弧接地方式。更多还原

【Abstract】 When single phase to earth fault occurs on a neutral non-direct grounded power system, it is necessary to select the fault circuit quickly. But, from existing status of this field, it has not been done very well. This paper introduces a novel fault circuit selecting method, which utilizes wavelets transform to obtain useful fault transient components.Firstly, A detailed analysis to fault transient course of these kinds of system is discussed, focusing on the resonance-grounded power system. Furtherly, a fault circuit selecting method based on fault transient components is presented.Secondly, Because wavelet analysis can change the time and frequency windows according to the variation of signals’ frequency, it can analyze the singularity of fault signals, and then confirm the accurate fault time efficiently. Then, The fault circuit selecting method utilizing wavelets transform is proposed to obtain useful fault transient components. The results of simulation denote that the methods in this paper are efficient and reliable.Lastly, The influences of arcing grounded are discussed. From the results of simulation, it is found that the fault circuit selecting method proposed in this thesis is applicable to arcing grounded.更多还原