电力系统谐波分析

海南大学

课程论文

题目：电力系统谐波分析

学号： B******* *名：***

年级： 07电气1班

学院：机电与工程学院

系别：电气系

专业：电气工程及其自动化

指导教师：***

完成日期： 2010 年 06月 15 日

摘要

谐波对电力系统和用电设备产生了严重的危害及影响，而小波变换为电力系统谐波信号分析提供了有力的分析工具。与Fourier变换相比，小波变换是时间频率的局部化分析，它通过伸缩平移运算对信号逐步进行多尺度细化，最终达到高频处时间细分，低频处频率细分，能自动适应时频信号分析的要求，从而可聚焦到信号的任意细节，解决了Fourier变换的困难问题，成为继Fourier变换以来在科学方法上的重大突破。有人把小波变换称为“数学显微镜”。

本设计探讨了小波变换的基本原理之后，就如何应用小波工具箱对系统的谐波信号进行了分析。主要内容如下：

首先，采用小波变换进行谐波检测的方法进行了系统仿真，通过仿真验证了小波分析具有时域和频域的双重分辨率，能够较好的解决傅立叶分析所不能解决的问题。

其次，在谐波分析中，采用小波分析算法，不仅能正确的得到各次谐波，而且对用傅立叶分析没法解决的有关信号的暂态分量的提取，暂态分量时间的定位，电压、电流波形的间断、突起、凹陷和瞬态分量的检测都具有较好的效果。

最后MATLAB仿真的结果验证了本文的分析方法的正确性和有效性。基本达到了实验目的。

关键词：谐波分析小波理论MATLAB

Abstract

Harmonics have a serious danger and affect in the power system and electrical equipment, but wavelet transform can provides a powerful analytical tool for harmonics signal analysis. Compared with the Fourier transform, wavelet transform is the localized analysis of time frequency, which refines the signal multi-scale by scalabling and shifting operation step-by-step. Finally it meets the requirement of high-frequency time and low-frequency frequency subdivided, and of automatically adapting to time-frequency signal analysis. It can focus on arbitrary particulars of signal , solving the difficult problems of the Fourier transform. It is a major breakthrough in science method since the Fourier transform. Someone praised wavelet transform as the “mathematical microscope”.

After discussing the basic principles of wavelet transform, this Design discussed how to use the wavelet toolbox to analy the harmonic signals. They are as follows:

Firstly, the Harmonic Detection method was simulated by Wavelet Transform, and the simulation shows that the Wavelet Transform has double resolutions in both time and frequency domains, which can solve the problem that the Fourier Transform can't do well.

Secondly, we could not only correctly get various orders of harmonics, but also effectively solve how to draw the transient component of the signal ,and how to locate the time of transient component of the signal ,and solve the problem of intermittent and Processes and depression of the voltage and current wave, and solve how to detect transient component,and the Fourie are not available.

Finally,MATLAB simulation results verify the correctness and effectiveness of the analytical methods. It achieves the basic purpose of the experiment.

Key words: Harmonic measurement Wavelet theory MATLAB

目录

前言 5 第一章谐波的分析 6

1.1小波分析 6

第二章谐波检测仿真分析 8

2.1谐波信号模型的建立 8

2.1.1MATLAB 8

2.1.2电力系统谐波信号 10

2.2MATLAB小波分析 15

2.2.1信号模型一的小波分析模型 16

2.2.2信号模型二的小波分析模型 17

2.2.3信号模型三的小波分析模型 18

2.2.4信号模型四的小波分析模型 19

第三章结论 20

致谢 21

参考文献 21