压缩感知理论在小电流接地故障选线中的应用

发布时间：2018-05-18 20:28

本文选题：小电流接地系统 + 故障选线　；参考：《西南交通大学》2016年硕士论文

【摘要】：小电流接地系统凭借自身优越的供电可靠性,得以在国内中低压配电网中被广泛采用。可是,单相接地故障现象在电网中发生的频率较高,由于发生单相接地故障时产生的故障电流很小、选线获取的样本数据过多造成选线时间长、故障信号的精确获取难等很多因素,对于单相接地故障选线这个难题,很长时间以来都在寻找相应的有效对策。怎样才能使得故障线路的排除过程变得更加准确、快速,无疑是非常重要且意义深远的。本文针对这一难题,围绕开展相关研究工作,在人们已有的大量研究基础上,进一步探索和完善故障选线方法,弥补现有选线方式存在的不足。先针对小电流接地系统发生单相接地故障时会有哪些突出的特点显现出来,本文对此展开了较为具体的讨论和梳理,并且就稳态以及暂态两个方面,归纳总结了故障特征量在非故障线路与故障线路上所存在的不同之处。以此为后续的研究分析做好充足的准备以及铺好扎实的理论基础。其次介绍了当前已经存在的几种传统选线方式,分析它们目前各自面对着哪些约束,并对这些方法中所存在问题及缺陷进行归纳。最后,通过以上的分析和研究说明,如果要使得最初的故障分析更加精确快速、使得选线更加准确,那么刚开始对于故障信号的精确获取是非常重要的。当前采用暂态分量来对线路进行故障判断的方法,很多是通过线路的零序量所存在的特征差异来判断的,而传统的高速采样有可能会使部分高频分量发生折叠,导致信号混淆。因此能否获得更加精确的零序量关系着选线的成败,但是只有达到了高速的采样频率才能使得故障信号的获取更加准确。本文对一种刚刚兴起的全新的数据采集方法压缩感知理论进行分析研究,并将其应用于小电流单相接地故障选线中,从根本上解决采样率限制的问题,精确获取故障信号,从而提高故障选线的准确度。本文通过应用一种较新的压缩感知理论,尝试实现在采样频率上的突破,使得故障选线方法不再受其条件的约束,然后获取精确的恢复信号。除此之外,还将该理论与希尔伯特一黄变换(HHT)相融合,建立仿真模型并验证该选线方法在不同类型下小电流接地故障选线的正确性以及可靠性,获得了预期的效果。
[Abstract]:Low-current grounding system is widely used in medium-low-voltage distribution network because of its superior power supply reliability. However, the frequency of single-phase grounding fault is high in the power network. Because the fault current generated by single-phase grounding fault is very small and the sample data of line selection is too much, the line selection time is long. There are many factors such as the difficulty of obtaining the fault signal accurately. For a long time the problem of single-phase grounding fault line selection has been looking for the corresponding effective countermeasures. How to make the troubleshooting process more accurate and rapid is undoubtedly very important and far-reaching. In view of this problem, this paper focuses on the related research work, on the basis of a large number of existing research, further exploration and improvement of fault line selection methods, to make up for the shortcomings of the existing methods of line selection. In this paper, the characteristics of single-phase grounding fault in low-current grounding system are discussed and combed in detail, and the steady state and transient state are discussed as well. The differences of fault characteristics between non-fault lines and fault lines are summarized. This is the following research and analysis to make adequate preparation and lay a solid theoretical foundation. Secondly, this paper introduces several existing traditional route selection methods, analyzes the constraints they face at present, and sums up the problems and defects in these methods. Finally, through the above analysis and research, if we want to make the initial fault analysis more accurate and fast, and make the line selection more accurate, it is very important to obtain the fault signal at the beginning. At present, the transient component is used to judge the fault of the transmission line, many of them are judged by the characteristic difference of the zero-sequence quantity of the line, while the traditional high-speed sampling may make part of the high-frequency component fold and cause the signal confusion. Therefore, the success of line selection depends on whether or not a more accurate zero sequence can be obtained, but only with a high sampling frequency can the fault signal be obtained more accurately. In this paper, a new data acquisition method, compression sensing theory, is analyzed and studied, and it is applied to the fault line selection of single-phase earthing fault with small current. The problem of limiting the sampling rate is solved fundamentally and the fault signal is obtained accurately. In order to improve the accuracy of fault line selection. By applying a new compression sensing theory, this paper attempts to achieve a breakthrough in the sampling frequency so that the fault line selection method is no longer constrained by its conditions, and then the accurate recovery signal is obtained. In addition, the theory is combined with Hilbert-Huang transform (HHT) to establish a simulation model and verify the correctness and reliability of this method in different types of low-current grounding fault line selection. The expected results are obtained.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM862

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