【作者】 王丽娟；

【导师】 姚李孝；

【作者基本信息】 西安理工大学 ， 水利水电工程， 2005， 硕士

【摘要】 本文提出了基于小波变换的小电流接地系统单相接地故障选线和测距方法。在分析了小电流接地系统发生单相接地故障时零序电流的暂态过程及特点的基础上，提出了利用小波变换提取故障暂态信息的选线方法。对故障后的暂态分量进行小波变换，通过比较零序电流小波变换模极大值的大小和极性实现故障选线。该方法克服了传统方法中因稳态零序电流较小而误选的缺点，且不受故障电阻及系统运行方式的影响，能可靠实现故障选线。 现代电力系统中对小电流接地系统的故障测距研究相对较少，主要是因为配电网的网络结构复杂，且故障特征不明显，这些都给小电流接地系统的故障测距研究带来了困难。行波测距法具有较高的可靠性和精度，抗干扰能力强，且不受故障电阻及系统运行方式的影响。因而，本文将行波法应用到小电流接地系统的故障测距中，采用单端测距算法，对故障后的三相电压、电流行波进行相模变换。由于地模分量在传播过程中存在严重衰耗且受线路参数的影响较大，而线模分量受频率的影响较小，所以从线模分量中提取反向电压行波，并对其进行二进小波变换。根据小波变换的奇异性理论检测初始行波波头及故障点反射波的到达时刻，进而计算出故障距离，实现故障测距。 最后，利用MATLAB搭建仿真模型，对本文提出的选线和测距算法进行验证。结果表明，利用小波变换实现小电流接地系统单相接地故障定位的方法是合理的和行之有效的。更多还原

【Abstract】 This paper presents a method of fault line selection and fault location for single-phase earth fault in non-solid earthed power system based on wavelet transform. It analyses the transient course and characteristics of zero sequence current when a single-phase earth fault happened in non-solid earthed power system. A method of fault line selection which uses wavelet transform extract the transient fault information is brought forward. Transforming the post-fault transient component with wavelet, the fault line is found through comparing the magnitude and polarity of wavelet transform of zero sequence currents. This method overcomes the defects of traditional fault line selection means, which will misjudge the fault line when the steady zero sequence current is very small. It is free from the fault resistance and the neutral grounding modes and can find the fault line reliability.The research of fault location in non-solid earthed power system is relatively small in modern power system. The leading causes are the network structure of distribution system is complicated and the fault characteristics are not very obvious, which bring some problems to the research of fault location. The traveling wave fault location has high reliability, accuracy and anti-disturbance capability, and it also immunes from the更多还原