基于Matlab的加窗FFT电力系统谐波分析.docx

基于Matlab的加窗FFT电力系统谐波分析基于Matlab的加窗FFT电力系统谐波分析摘要：随着电力系统中非线性电力元件的增多，电网中谐波分量大大增加，谐波污染的情况也日益严重，对电力系统的安全经济运行造成了极大的影响。谐波测量是谐波问题研究的主要依据，实时测量电网中的谐波含量，确切掌握电网中谐波的实际情况，对于防止谐波危害，维护电网的安全运行是十分必要的。对于谐波的分析，常用的分析方法有快速傅里叶变换（FFT），沃尔什变换（Walsh）,哈里特变换（Harley）和小波变换（Wavelets）等。快速傅里叶变换方法因为具有实现简单，精确度较好，功能较为丰富等优点，所以被用来作为常用的谐波检测方法，但是由于谐波分析时同步采样的难度较大，造成采样频谱泄露、栅栏效应，频率混叠等问题，使得算出的谐波精度不高。针对快速傅里叶变换测量谐波精度不足的缺点，通常采用加窗值FFT和全相位FFT等方式进行FFT的优化。本文的重点工作是：分析FFT算法存在的缺陷以及针对这些缺陷进行的改进，分析了多种窗函数的特性，并根据多种穿函数的优缺点，适当的将多个窗函数组合起来，达到更高的精度，仿真的结果表明，这种方法是切实可行的，能够达到足够的精度要求。关键词：电力系统，谐波，FFT，窗函数，加窗。Harmonic analysis of power system based on Matlab for FFT power systemAbstract：With the increase of power system nonlinear electric elements, harmonic component is greatly increased, harmonic pollution is becoming more and more serious, the safe and economic operation of power system caused a great impact. Harmonic measurement is a main basis in the study of harmonic problems, real-time measurement in power grid harmonic content, the exact grasp the actual conditions of power network harmonic, to prevent the harm of harmonics, maintenance and the safety operation of the power grid is very necessary. For the harmonic analysis, the common methods of analysis are fast Fourier transform (FFT), Walsh transform (Walsh), Harriet transform (Harley) and wavelet transform (Wavelets), etc. Fast Fourier transform method for its realization is simple, good accuracy and more feature rich and advantages, it is used for as a commonly used harmonic detection methods, but due to the harmonic analysis of synchronous sampling difficulty is greater, cause sampling frequency spectrum leakage and picket fence effect, frequency mixed stack and other issues, making the calculated harmonic precision is not high. In view of the shortcomings of the fast Fourier transform for measuring harmonic accuracy, the optimization of FFT by adding window value FFT and full phase FFT is usually used. The focus of this paper is: analysis of FFT algorithm in the presence of