小电流接地系统故障选线新方法研究

文档编号:ZD1384  文档字数:28788,页数:45

文档题目：小电流接地系统单相接地故障选线的研究
摘　要
 电流接地系统在提高供电可靠性上具有优越性，从而在我国的配电网中得到广泛应用。该系统发生单相接地故障的机率最高，当小电流接地系统发生单相接地故障时，长时间的接地运行极易形成两点或多点接地短路，弧光接地还会引起全系统过电压，破坏系统的安全运行，因此如何快速准确的排除故障线路，对系统的运行具有重要的意义。但是由于单相接地故障产生的故障电流很小等诸多原因，单相接地故障选线问题一直没有得到很好的解决。本文针对这个问题开展研究工作，旨在发现现有选线方式存在的不足，进一步探索故障选线方法。作为研究工作的基础，首先本文系统地分析了小电流接地系统发生单相接地故障的特点，从暂态和稳态两方面研究了故障特征量在正常线路和故障线路上的差异，为本文的后期工作提供理论基础。在理论分析的基础上，对现有的选线方法进行了简单的研究，分析了各种选线方法的局限性，总结了目前选线困难的主要原因。最后，指出了基于单一选线方法都具有其各自的局限性，应对各选线方法合理地进行综合，发挥各种选线方法之间的互补性，形成多判据的综合选线方法。本文对已提出的综合选线方法加以改进，以故障测度为基准，融合了零序电流群体比幅法、注入信号法、基于零序电流谐波畸变率特性选线法、暂态零序电流互积求和法、衰减直流分量选线法以及小波包分析选线法等六种选线方法，构造了一种基于模糊理论的多判据综合选线方法。对各种单一选线方法设定了故障测度隶属函数和各判据的权重系数隶属函数。根据系统结构以及多种故障特征量，通过模糊决策得到最终的选线结果。并对所改进的综合选线方法进行了数字仿真，取得了预期的结果，证明了它的正确性、可靠性。最后，针对目前传统的选线方法只利用待测故障的故障信息选线，而没有利用到已有故障样本中含有大量对故障选线有利的信息，本文在基于对已有故障样本的故障信息分析的基础上，提出了利用灰关联分析对新的待测故障进行选线，建立了基于注入信号和小波包分解的灰关联分析故障选线方法。且通过大量的数字仿真实验，验证所建立的选线体系的可行性。基于灰关联分析的选线方法从选线思路上有别于传统的选线方法，开辟了一条新的故障选线道路，与所改进的基于模糊理论多判据综合选线方法相结合，能起到有效的验证作用，选线的精度将得到大大加强，针对目前小电流接地电网单相接地故障选线困难具有一定的现实意义。
关键词：小电流接地系统；故障选线；故障测度；信息融合：模糊理论；灰关联分析

 
Title: Single phase small current grounding system of fault line selection
 
ABSTRACT
 Small current grounding system to improve power supply reliability in the superiority, which in our distribution network has been widely used. The system is single phase ground fault at the highest risk, when a small current grounding system, single-phase ground fault occurs, the formation of a long ground run two or more points easily ground short circuit, grounding can also cause system-wide arc over voltage, damage the safe operation of the system, how to troubleshoot quickly and accurately route, the operation of the system is significant. However, due to single-phase ground fault resulting fault current is very small, and many other reasons, the single phase to ground fault line problem has never been solved. In this paper, this research work aims to find ways of existing shortcomings in alignment, and further explore the fault line selection method. As a basis for research work, the first systematic analysis of this small current grounding system fault occurs the characteristics of single phase, from both transient and steady state characteristics of the fault and fault lines in the normal amount of the difference in line for this article provide a theoretical basis for later work. In the theoretical analysis, based on the alignment of the existing methods of a simple, analyzes the limitations of a variety of line selection, summarized the main reason the current alignment difficulties. Finally, it was based on a single line selection methods have their respective limitations, address the method to select reasonably comprehensive, method to select between a variety of play complement each other, forming an integrated multi-line selection criteria. This paper has proposed a comprehensive method to select improved to failure as the benchmark measure, the integration of groups than the amplitude of zero sequence current law, injecting signal, based on zero sequence current harmonic distortion characteristics of line selection method, the transient zero sequence current summation of each product, decaying line selection method and the wavelet packet analysis of six Line selection method to select, construct a multi-criteria based on fuzzy comprehensive method to select. A variety of single fault line selection method set membership function and the criterion measure of the weight coefficients of the membership function. According to the system structure and the amount of a variety of fault feature, the fuzzy decision-making to get the final alignment result. And the improved method to select for the integrated digital simulation, and achieved the expected results, proof of its validity and reliability. Finally, the current traditional method to select only the information by the fault under test fault line selection, without samples used to have trouble on the Fault Line contains a lot of favorable information, this paper has been based on fault samples of fault information Based on the analysis presented, Grey relational analysis tested the new fault line selection, established based on the injection signal and the wavelet packet decomposition of the gray relational analysis method of fault line. And through a large number of digital simulation experiments to verify the established alignment system is feasible. Grey relational analysis method to select the train of thought from the choice of lines is different from the traditional method to select, has opened up a new fault line the road, with the improved multi-criteria based on fuzzy comprehensive method to select the combination can play an effective role in verification, the accuracy of alignment will be greatly enhanced, the small current grounding power for the current single-phase to ground fault line has a certain practical significance difficult. Key words： small current grounding system; fault line; failure measure; information fusion: fuzzy theory; Grey relational analysis
 
 
 目录
1 绪论  1
 1．1本文的研究意义 1
 1．2国内外研究现状 2
 1．3本文的主要工作 2
2小电流接地系统单相接地故障分析 5
 2．1电力系统中性点接地方式介绍 5
 2．1．1中性点不接地 5
 2．1．2中性点经消弧线圈接地 6
 2．1．3中性点经高阻接地 7
2．2小电流接地系统单相接地故障基本特征 7
 2．2．1中性点不接地系统单相接地故障特征 7
 2．2．2中性点经消弧线圈接地系统单相接地故障特征 10
 2．2．3小电流接地系统单相接地故障的暂态分析 11
3 选线方法分析及解决思路 15
3．1现有选线方法概述 15
 3．1．1稳态选线方法 15
 3．1．2暂态选线方法 17
3．2选线的误判问题 18
3．3选线的局限及解决思路 19
 3．3．1选线局限性 19
 3．3．2选线解决思路 20
4 基于模糊理论的多判据综合选线方法 23
4．1信息融合与故障选线 23
4．2模糊理论 23
4．3故障测度和判据权重系数 25
4．4基于模糊理论的多判据综合选线体系 25
 4．4．1多种单一判据的选取 25
 4．4．2故障测度隶属函数和权重系数隶属函数的建立 26
4.5仿真及数据分析 29
 4．5．1仿真模型的建立 29
 4．5．2中性点不接地系统故障仿真及数据分 29
5 基于灰关联分析的故障选线方法 31
 5．1灰关联分析理论 31
 5．2基于灰关联分析的故障选线方法 31
 5．3本章小结 32
6 结论与展望 33
致  谢 35
参考文献 36

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