摘要因故障电流小，单相故障后系统可带故障继续运行一段时间，不影响对负荷的持续供电等特点，国内外中低压配电网中性点广泛采用小电流接地方式。在配电网中，单相接地故障率最高，但由于故障电流微弱、电弧不稳定等原因，小电流接地系统单相接地故障选线问题一直没有得到有效的解决。本文针对这个问题开展研究工作。65984

本文首先论述了小电流接地系统的主要特点。其次，分析了四种选线方法的基本原理。并以Matlab软件为平台，对小电流接地系统的单相接地故障进行建模，在小电流接地系统中进行金属性接地、高阻接地进行仿真，根据仿真结果总结了各选线方法自适应的范围，突出优势和自身的局限性。最后提出了待解决问题和展望。

毕业论文关键词： 小电流接地系统；故障选线； MATLAB.

毕业设计说明书（论文）外文摘要

Title  The Study of Small Current Grounding System in                

          Single-Phase Ground Fault Line Selection                                                

Abstract

The countries have widely adopted neutral point non-effective grounding mode in medial and low voltage distribution networks, because the fault current is small when system occurs single-phase grounding fault, the system may operate for a while with trouble which does not affect the normal power supplying to the load. The rate of single-phase grounding fault is the highest in distribution network, However, due to fault current is small and the electricity arc is unstable, the line selection problem on small current system single-phase grounding fault has not been effectively settled, and the article aims to solving this problem.

The article firstly introduces the features of small current grounding 

System. Secondly, analyzes the basic principle of four kinds of line 

selection methods. Thirdly, build a simulation model of small current 

grounding system based on the Matlab software for platform, simulate 

metallic grounding and high-resistance grounding in small current 

system. And summarize the scope, advantages, and limits of different 

methods. Lastly, raise unsolved problems and prospects.

Keywords: Small Current Grounding system, Line Selection, MATLAB.

目   次

1  绪论 1

1.1 研究背景和意义 1

1.2 国内外研究现状及发展趋势 1

1.3 论文的主要工作 2

2  小电流接地系统单相接地故障过程分析 3

2.1 电力系统各种接线方式介绍 3

2.2 小电流接地系统三种接地方式下的故障分析 4

3  四种选线方法原理介绍 10

3.1 零序电流比幅法 10

3.2 零序功率方向法 10

3.3 零序五次谐波分量法 11

3.4 注入信号法 11

4  小电流接地系统单相接地故障选线方法的matlab仿真 14

4.1 MATLAB及Simulink简介 14

4.2 小电流接地系统的MATLAB Simulink仿真模型