基于改进双谱线插值FFT算法的电力谐波分析

Power Harmonic Analysis Based on Improved Algorithm for Double-spectrum-line Interpolation FFT

针对电力系统谐波分析中常用的双谱线插值FFT算法开方运算量大的问题,提出一种有效减少开方运算的改进双谱线插值算法。该算法利用窗函数主瓣内相邻谱线间的相位特性,改进了修正谐波幅值时谐波频率点附近最大、次最大两条谱线幅值之和及频率偏差的计算方法,使计算谐波幅值需要的开方运算减小为常规算法的一半,计算频率偏差完全无需开方运算,从而大幅降低运算量,提高了谐波分析的实时性。在Matlab中对改进算法和常规算法进行了仿真对比,结果发现,改进算法不仅计算量小,而且精度很高。

Aiming at the shortcomings of large computing capacity of double-spectrum-line interpolation FFT that is a commonly used algorithm for power harmonic analysis, an improved algorithm for double-spectrum-line interpolation FFT is presented, By using the phase characteristics of adjacent spectrum lines in main lobe of window function, the new algorithm improves the calculating methods of sum of the two spectrum lines, amplitude which are maximum and second maximum amplitude spectrum lines near harmonic frequency, as well as improves the calculating methods of the frequency deviation. It reduces the root operation by half for amplitude correction, and omits the root operation for frequency deviation calculation completely. So, it greatly reduces the computing capacity and improves the real-time performance for power harmonic analysis. Compared with the traditional method in Matlab, simulation results show that the improved algorithm is of high accuracy and small amount of calculation.