毕业设计（论文）
题目 Matlab在输电线路故障测距中的应用
二级学院 电子信息与自动化学院 专 业 电气工程及其自动化
班 级 110070401
学生姓名 施永平 学号 11007990223 指导教师 雷绍兰 职称 教授 时 间2014年2月24日至6月10日
Matlab在输电线路故障测距中的应用
目录
摘要 ....................................................................................................................................... 4 Abstract ................................................................................................................................ 5 1绪论 .................................................................................................................................... 1
1.1 引言 ......................................................................................................................... 1 1.2本课题的研究目的及意义 ...................................................................................... 1 1.3输电线路故障测距方法的研究现状 ...................................................................... 2
1.3.1行波测距法 .................................................................................................... 2 1.3.2故障分析法 .................................................................................................... 3 1.3.3智能化测距法 ................................................................................................ 3 1.4本文的主要内容 ...................................................................................................... 4 2 高压输电线路的行波测距方法 ....................................................................................... 5
2.2 行波的传输特性 ..................................................................................................... 5 2.3行波的反射和折射 .................................................................................................. 7 2.4行波测距法的基本原理 .......................................................................................... 8
2.4.1 单端测距法 ................................................................................................... 8 2.4.2双端测距法 .................................................................................................... 9 2.5本章小结 ................................................................................................................ 10 3 基于小波变换的输电线路行波测距 ............................................................................. 11
3.1 连续小波变换的基本概念 ................................................................................... 11 3.2 小波变换模极大值理论 ....................................................................................... 12 3.3 本章小结 ............................................................................................................... 13 4 基于Matlab的行波故障测距仿真分析 ....................................................................... 15
4.1 仿真工具介绍 ....................................................................................................... 15
4.1.1 Matlab PSB简介 .......................................................................................... 15 4.1.2 Matlab中的小波分析工具箱 ...................................................................... 15 4.2 输电线路故障仿真模型 ....................................................................................... 16 4.3 输电线路故障行波的提取 ................................................................................... 16 4.4 仿真及结果分析 ................................................................................................. 17
4.4.1 接地电阻为0的单相接地短路故障测距仿真分析 ................................. 18 4.4.2 行波故障测距在不同故障距离、不同故障类型和不同接地电阻的仿真分析 ........................................................................................................................... 22 4.5 输电线路单端行波测距和双端行波测距的比较 ............................................... 25 4.6 本章小结 ............................................................................................................... 25 5 结论 ................................................................................................................................. 26 致谢 ..................................................................................................................................... 27
Matlab在输电线路故障测距中的应用
参考文献 ............................................................................................................................. 28 附录1 故障行波提取程序 ................................................................................................ 30
Matlab在输电线路故障测距中的应用
摘要
输电线路担负着输送电能的作用，一直被视为电力系统的大动脉，而输电线路故障又是电力系统故障的常见问题。准确、及时的输电线路故障测距能够缩短线路故障的时间和减小故障带来的经济损失，所以输电线路故障测距的研究一直是国内外研究的热点。
本文首先介绍了目前故障测距方法研究的现状，讲述了现代社会常用的输电线路故障测距方法，对常用的行波故障测距法、故障分析法及智能化测距法的理论原理进行了简单的介绍分析。接着对行波故障测距法进行了深入的分析，其中仔细讲述了基于小波变换的行波故障测距算法。为了验证行波故障测距法的可行性，本文利用Matlab建立输电线路故障模型，且基于输电线路的不同故障类型、不同接地电阻及不同故障点对其进行仿真分析，并用单端法和双端法对仿真分析后的数据进行故障定位，结果得出单端和双端行波测距法都有很高的精确度，而且还表明了不同的故障类型、不同的接地电阻以及不同的故障点不会影响电压行波故障测距的精度。 关键词：电力系统；输电线路；故障测距；行波；Matlab
Matlab在输电线路故障测距中的应用
Abstract
Transmission lines act as the transmission of electricity,has been regarded as the artery of the power system,and transmission line fault is a common problem of electric power system fault.Accurate and timely transmission line fault location can shorten the time of line fault and reduce the financial loss cause of transmission line fault.So the study of transmission line fault location is the focus of research at home and abroad.
This paper first introduces the current research situation of fault location method,tells the frequently-used transmission line fault location in modern society.And for the common traveling wave fault location method,the fault analysis and intelligent ranging method,this paper has carried on the simple introduction and analysis of the theory. Then the traveling wave fault location method is carried on the thorough analysis,and among them there carefully tell the traveling wave fault location algorithm based on wavelet transform.In order to verify the feasibility of traveling wave fault location method, this paper, by using Matlab power transmission line fault model is set up, and based on different fault types, different grounding resistance and different point of failure of the transmission line ,we have the simulation analysis on them respectively.We use the single end method and double ends method of traveling wave fault location to calculate the fault location with the simulation analysis of the data for fault.The results show that the single end method and double ends method of traveling wave fault location both have a high accuracy,and also shows that the different fault types, different grounding resistance and different point of failure will not affect the accuracy of voltage traveling wave fault location.
Keywords:The power system;Transmission line;Fault location; Traveling wave; Matlab