摘要随着我国发展程度的不断提升，城市电网的等级也在逐步的清晰和明确起来，我们在不同地区，甚至是不同城市采取不同的电压等级划分方法，但是还是有一定规律可以遵循，通常来说我国最高的电压等级是750千伏，当然在这种等级之下还有很多电压等级可以划分，经常出现在我们日常生活中的就是220千伏的电压等级了，由此我们可以得知，不同的电压等级我们应该采取不同的对待方式。75584

我国不同地区不同城市的电压等级是不一样的，按照我国的电气规范可划分为几个不同的等级，中性点接地也会因此分为不同的形式。其中最常用的是按照接地短路时接地电流的大小为依据分为大电流接地系统和小电流接地系统两种表现形式。向用户的供电安全与质量是否达到标准会对中性点连接方式造成一定的影响，例如系统能不能带一相故障接地时继续运行，或者系统会不会限制过电压要求这两个因素。我国普遍采取以下接地方式，在110kV及以上的电压等级使用直接接地，35kv等级或更小的使用本文介绍的小电流接地方式。

目前我国3～66kV配电网中，普遍采用非直接接地系统，就是常说的小电流接地系统。而此类系统发生最多的是单相接地故障，对于故障线路的辨别主要强调快和准，这也是比较困难的地方。所以在本论文中，仔细回顾了小电流接地系统单相接地故障选线方法的发展历史，并且对现有的各种选线原理和方法做了系统性的归纳和比较，也提出尚未解决的问题与建议。并且利用Matlab 仿真平台的Simulink 元件库中的各种元件搭建一个小电流接地的模型，逐步调整各个元件的设置参数，逐一进行对比，并且仔细的观察呈现出的波形走势，进行归纳。在本文的结尾，我们可以得到一个关于选线的结论，同时也会认识到选线方法的不足，希望可以在未来有所创新。

该论文有图18幅，表1个，参考文献45篇。

毕业论文关键词：小电流接地系统  单相接地故障  故障选线  Matlab 仿真

Fault Line Selection for Single Phase to Earth Fault in Small Current Grounding System

Abstract With the development of our country continuously improve the level of city power grid level also gradually clear up, we in different regions, and even different city take the voltage grading in different ways, but there are still some rules to follow, usually our highest voltage is 750 kV, of course at this level under there are a lot of voltage can be pided, the voltage level often appear in our daily life is 220 kV, so we can see that different voltage levels we should adopt different treatment method。 The different voltage city in different regions of China is not the same, in accordance with the electrical specification of China can be pided into several different grades, neutral grounding will be pided into different forms。 One of the most commonly used is to ground short circuit grounding current size is pided into large basis Two forms of current grounding system and the non-effectively grounded system。 The power supply to the safety and quality of the user meets the standards of neutral point connection will cause certain impact, such as the system can continue to run with a phase grounding fault, or the system will not limit the over-voltage requirements of these two factors。 Generally take the following grounding mode in 110kV and above voltage levels using direct grounding, 35kV grade or less use of the small current grounding。 At present 3 ~ 66kV in the distribution network, widely used in non direct ground system, small current grounding system is often said。 This system is the largest single phase grounding fault, the fault line for discrimination mainly emphasizes fast and accurate, it is difficult to place。 So in this paper, a careful review of the small current grounding system fault line selection Conclusion about waveform, comparison and inductive approach to the development of history, and the existing line selection principle and method of the system has not yet been proposed to solve the problems and suggestions。 And the use of Matlab simulation platform Simulink component library in a variety of components to build a small current grounding model, and gradually adjust each element of the set parameters, one by one are compared, and careful observation showed the trend are summarized。 In the end, we can get a fault line, also will realize fault line selection method, hope in future innovation。 The paper has 18 pictures and only 1table。 It also has 45  reference documentations。