【作者】 史啸歌；

【导师】 张化光；

【作者基本信息】 东北大学 ， 控制理论与控制工程， 2005， 硕士

【摘要】 随着社会经济的发展,对电力需求日益增长,同时对供电质量和配电自动化的水平提出了更高的要求。配电网大多采用小电流接地系统,单相接地故障定位研究一直是电力系统的研究热点。 小波变换是近年来发展壮大起来的应用数学领域的一个分支,其在电力系统中也得到了广泛的应用。作为一种全新的时频分析方法,它可以随着信号频率高低的变化自适应地调节其时频窗的形状,被认为是暂态信号的理想分析工具。通过对单相接地故障后的稳态和暂态过程分析并比较后得出结论,暂态过程携带丰富的故障信息,小波分析方法完全有能力提取出这些“隐藏”的信息。故障定位包含两个部分,一是故障选线,即在各条出线中选出发生故障的线路;二是故障测距,即准确测量故障线路的故障点位置。 文章提出了一种新的选线判据,它利用各线路零序电流暂态分量的小波变换的细节分量,依据在特征尺度下各值的大小及极性判断出故障线路;并通过故障发生后对线路中电流行波的分析,提出了基于行波法的故障选线判据,补充了前一种选线方法的单一与不足,重要的是与后续的基于电流行波的故障测距在理论上达到一致性。文章对利用行波法进行故障测距进行了尝试,利用小波变换模极大值检测理论,检测行波到达时刻,实现故障测距。 经过大量仿真试验验证了选线判据与测距判据的有效性和准确性,并对故障定位系统装置研制进行了尝试性的总体结构设计和软件设计,提出了基于Matcom与VisulC++相结合的软件设计方法。更多还原

【Abstract】 With the development of society and economy, the demand for power supply and its ability has increased rapidly in recent years. Most of power distribution network system adopts the small current neutral grounding system. The research of single phase-to-earth fault location is the focus in this field nowadays.Wavelet transform is a new and promising theory in mathematics, and it has an extensive application in the power system now. It has been proved to be very efficient for transient signal analysis. According to a set of damped oscillations named "wavelets", it builds a new representation for the analyzed signal. Thought analyzing the characters of the steady signal and the transient signal after the single phase-to-earth fault occurring, we draw a conclusion that the transient signal provided with the important fault info. According to the wavelet analysis, we can find out those "hidden" info. Fault location includes two parts. One is fault line selection, the other is fault distance detection.The paper brings forward a bran-new approach for fault line selection. By transforming the zero-sequence current of fault signal, we can tell easily on which line the faults have occurred. The major point here is to compare the maximum points of the details, either their magnitudes or directions can be used to identify the fault line. Moreover, by analyzing the traveling wave after single phase-to-earth fault occurred, we put forward another approach based on current traveling wave for fault line selection. This approach is powerfully complementary for the former one, and the more important point is it achieves a theoretic identity with fault distance detection arithmetic that putting forward in the paper. The fault distance detection principle that utilizes traveling wave appears in the small-current-grounding system. Using the powerful function of wavelet in the face of singular detection, the time that the traveling wave crest arrives is detected and the fault distance detection is realized.By plenty of simulation test, the results show that the methods putting forward更多还原