电力系统间谐波检测算法设计与仿真
毕业论文关键词：间谐波，傅里叶变换，窗函数，小波包
Abstract With the increase of nonlinear equipment load application and the growth trendamong power grid harmonic content, the harm has aroused people's attention.The detectionof harmonics is the premise of inhibition to analyze it.Therefore, the study of power systemharmonics detection algorithm has a good practical application value.Based on containing harmonic in power system harmonics,the voltage signal model isselected as the research object.The paper uses FFT, harmonics detection and window FFTalgorithm to analyse harmonics. the detection of harmonics in the MATLAB environmentto achieve the algorithm and the simulation with the model have been finished.In this paper,the main work is as follows:(1) The paper aims at under asynchronous sampling condition and uses FFTalgorithm directly to solve the problem of low precision of harmonics detection. this paperanalyzes the characteristics of window function and selects the hanning window to reducethe error value. Simplified formula of add window interpolation FFT algorithm has beendeduced. the direct FFT and window FFT harmonics detection algorithm are simulated, thesimulation results are given.(2) The paper uses wavelet packet characteristic to complete the detection of voltagesignal frequency components.The simulation results show that: add window FFT algorithm can well solve theharmonic detection between the non synchronous sampling in the problem of low precision,wavelet packet decomposition can estimate signal frequency of the ingredients.
Key words: harmonics, Fourier transform, window function, wavelet packet
目录
第一章绪论1
1.1研究的目的和意义.1
1.2间谐波的基本概念.2
1.3间谐波和谐波的区别3
1.4间谐波波源和它的危害..4
1.5研究现状6
1.6本文主要研究内容.7
第二章基于傅里叶变换的间谐波检测算法8
2.1傅里叶变换..8
2.1.1傅里叶变换分析法8
2.1.2离散傅里叶变换和快速傅里叶变换8
2.2电力系统中间谐波检测的fft算法.9
2.3影响间谐波检测精度的因素10
2.3.1栅栏效应..10
2.3.2频谱泄漏..10
2.4算法的仿真及其结果.11
2.5本章小结.14
第三章加窗傅里叶变换的间谐波检测算法.15
3.1常见的窗函数及其特性15
3.1.1矩形窗.15
3.1.2Hanning窗16
3.1.3Hamming窗.16
3.1.4Blackman窗.17
3.2窗函数选择原则18
3.3加hanning窗的FFT算法..18
3.4算法的仿真及其结果分析.20
3.5本章小结.21
第四章基于小波包的间谐波频率检测23
4.1小波包的研究意义..23
4.2小波包分解的优势..23