基于EMD与分形理论的小电流接地系统故障选线方法

发布时间：2018-01-06 03:17

本文关键词：基于EMD与分形理论的小电流接地系统故障选线方法　出处：《燕山大学》2014年硕士论文　论文类型：学位论文

【摘要】：电能是人们日常生活中最为重要的能源之一，电力系统的稳定关系着国民经济发展和国家安全，因此，预防和排除电力故障极其重要。我国当前主要采用小电流接地系统，发生单相接地故障的几率较大。由于故障稳态电流小、电流互感器不平衡、负荷的不规则变化、电弧不稳定等原因，使小电流接地系统的单相接地故障选线一直没能很好的解决。因此，小电流接地系统单相故障选线的研究已成为当前研究的热点和难点。本文首先介绍了国内外小电流接地系统单相接地故障选线的研究现状，对选线原理进行了归纳总结；系统的分析了小电流接地系统接地方式与形成故障的原理；然后详细的阐述了经验模态分解的基本理论与分形理论及其应用，在此基础上，重点研究了分形理论中的关联维数以及算法，与经验模态分解结合起来，进而提出了将经验模态分解与关联维数用于小电流接地系统中的单相接地故障选线的新方法。最后，本文通过电力系统仿真软件构建一个10.5kV的输电线路，将生成的零序电流信号通过MATLAB进行数据处理，通过对零序电流进行经验模态分解并提取谐波分量后计算其关联维数，通过关联维数的对比分析，得出了一个基于经验模态分解与关联维数的小电流接地系统的故障选线判据。为了测试该选线方法与判据的可靠性，本文通过大量的仿真算例，并全面考虑了接地方式、接地电阻、故障合闸角和故障相等影响小电流接地系统单相接地故障选线的因素，验证了该故障选线方法与判据的可靠性。结果表明，该方法不受上述因素的干扰，能正确选出故障线路，可靠性高，可以作为一种实际应用的新方法。
[Abstract]:The electricity is in people's daily life is one of the most important energy, the stability of the power system affects the development of national economy and national security, therefore, to prevent and eliminate the power failure is extremely important. The current mainly adopts the small current grounding system, single-phase grounding fault rate is larger because of fault current is small, the current transformer is not balanced, irregular change of load, arc instability and other reasons, the small current line selection has no good solution to the single-phase grounding fault of grounding system. Therefore, the small current grounding system single-phase fault line research has become a hot and difficult problem.
This paper first introduces the domestic and foreign small current grounding power system fault of line selection, on line selection principle are summarized; systematic analysis of the principle of small current grounding system and the formation of fault; then elaborates the basic theory of empirical mode decomposition and fractal theory and its application and on this basis, this paper focuses on the fractal theory of the correlation dimension and the algorithm, combined with empirical mode decomposition, and then put forward the EMD and correlation dimension for the new method of grounding line selection of single-phase fault of small current grounding system.
Finally, this paper constructs a 10.5kV transmission line through the power system simulation software, the zero sequence current signal generated by MATLAB data processing, based on the zero sequence current of the correlation dimension calculation of empirical mode decomposition and extraction of harmonic components, by comparing the correlation dimension analysis, obtained a fault in small current and empirical mode decomposition the correlation dimension of the grounding system based on a selection criterion.
In order to test the reliability of the line selection method and criterion, based on a large number of simulation examples, and full consideration of the grounding, grounding resistance, fault and fault closing angle equal effect of small current grounding system fault line selection factors, verify the reliability of line selection criterion method and the fault. The results show that this method is not disturbed by the above factors, can select fault line, high reliability, can be used as a new method for practical application.

【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM862

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