一种具有半波对称特性的电网谐波检测方法研究

针对一类电力系统的测试信号具有半波对称特性,提出了一种改进FFT算法.该算法在传统FFT算法的基础上省去了偶次谐波分量的计算,只分析奇次谐波,计算量是传统FFT的一半,大大提高了谐波的分析速度.在此基础上,为解决因非同步采样所导致的频率泄露问题,通过引入基于该改进算法的自适应频率跟踪流程,从而实现对这类电网谐波快速、精确的分析.MATLAB仿真结果表明,该算法响应速度快、实时性好、测量精度高,可有效地抑制电网频率和相位的突变影响,是一种工程实用方法.

A class of half-wave symmetry characteristics of the grid harmonic detection method research

An improved FFT algorithm considering the half-wave symmetric characteristic of the power system signals is presented based on the conventional FFT method.The new FFT algorithm analyzes only the odd harmonics in its calculation and omits the need for calculation of the even harmonics.So the calculation of the algorithm just has a half amount of the traditional FFT.It can improve the speed of the analysis of harmonic.On the base of this,an adaptive frequency tracking algorithm and processes were proposed to achieve accurate frequency tracking and harmonic analysis,in order to solve the problem of non-synchronous sampling.MATLAB simulation and experimental results show that the new algorithm and processes increase the speed and accuracy of responsible,effectively suppresses the sudden change impacts of frequency and phase of the grid.So it is a practical engineering method over the conventional method.