配电网单相接地故障选线及定位方法研究

【作者】 王旭；

【导师】 束洪春；

【作者基本信息】 昆明理工大学 ， 电力系统及其自动化， 2011， 硕士

【摘要】 近年来,随着电缆应用成本的下降和城市电网改造及城市美化工程的需要,电缆使用量大大增加,导致配电网的电缆线总长度增长,配电网的分布电容和分布电导将迅速增加,接地容性电流会大大超过运行规程规定值,需要采用中性点经消弧线圈接地的运行方式来提高系统供电的可靠性。本文分析了配电网单相接地故障选线及定位方法的研究现状,并结合配电网的新特征,利用MATLAB/Simulink仿真工具搭建了具有电缆线路,架空线,电缆-架空线混合线路的中性点经消弧线圈接地的多分支辐射网模型。在多分支辐射网仿真模型的基础上,进行了大量仿真试验,讨论了配电网中电缆的特性,消弧线圈的补偿特性,线路行波的电磁耦合特性,及故障合闸角和过渡电阻对故障行波的影响,由此,为配电网单相接地故障选线及定位方法的提出奠定了基础。深入分析了配电网发生单相接地故障时故障线路与健全线路在电气特征上的差别,利用数学形态学构造了峰谷检测器,并针对故障线路与健全线路的峰谷特性差别实现了故障选线。该形态峰谷检测方法不仅适用于零序电流选线,并且对只安装A、C两相电流互感器的情况也能实现正确选线。在实现故障选线的基础上,针对故障线路,为了更快的排除故障需要确定精确的故障位置,本文在分析了测量端信号频谱与故障位置关系的基础上,提出了利用S变换提取信号频谱并通过神经网络实现故障定位的方法；同时,本文还分析了故障行波特性与故障位置的对应关系,并在此基础上提出了利用首波头Lipischitz指数β和前三个波头时差的配电网单相接地故障智能测距方法。更多还原

【Abstract】 With the proportion of power cable in urban areas power grids increasing quickly, resulting in the distribution network distributed capacitance and conductance increase quickly, ground capacitive current of distribution network is increasing gradually, so that fault current increases when single-phase ground fault occurs, the compensating method of neutral point grounding through Arc-Suppression Coil is commonly used in our country. The paper analyzes some methods have been proposed for fault line detection and location of distribution systems, considering the new features, a Neutral point grounding via Arc-Suppression Coil of multi-branch simulation model was constructed with MATLAB/simulink tool, which have cable lines, overhead lines and cable-overhead lines.A large number of simulation experiments conducted based on multi-branch network simulation model. The characteristics of the cable in distribution network, the compensation characteristics of arc suppression coil, traveling wave of electromagnetic coupling characteristics, and different fault closing angles and transition resistances affect fault traveling wave have been discussed. Laid the foundation for the methods of fault line selection and location have been proposed. The mathematical morphology Top-Bottom detection method is applicable not only zero sequence current line selection but also A, C two-phase current to achieve the correct alignment.In the realization of fault line selection, based on the fault line, in order to faster troubleshooting need to determine the exact fault location, based on the the relationship between signal spectrum and fault location the use of S-transform through the neural network method for fault location is proposed. The paper also analyzes the fault location and fault lines wave the corresponding relationship, and on this basis proposed a fault location method by the first wave of Lipischitz indexβand the first three waves tip difference.更多还原