基于Hanning自相乘窗的电力谐波FFT分析方法

目前谐波分析准确度的关键在于窗函数具有优秀的旁瓣特性。提出了Hanning窗进行时域自相乘运算，得到一种新的Hanning自相乘窗，具有旁瓣特性随着相乘次数的增加不断提高的优点。同时提出基于五项余弦组合窗的四谱线插值FFT的电力谐波分析方法，利用曲线拟合函数得到四谱线插值修正公式。对该窗函数与Hanning窗，Nuttall4项5阶窗的四谱线插值进行仿真对比，验证提出的窗函数对幅值、相位、频率具有更高的分析精度。对南京化工园热电二次电流进行谐波分析进一步验证了所提出的窗函数的有效性。

An approach for electrical harmonic FFT analysis based on Hannning self-multiply window

The key of accuracy of current harmonic analysis is the window function with good sidelobe characteristics. This paper proposes Hanning self-multiply window for the first time, which is constructed by the self multiply of Hanning window in time domain, and it has the advantage that its sidelobe characteristics is increasing with the increase of times of self multiply. At the same time, it puts forward four-spectrum-line interpolation FFT power harmonic analysis method based on five terms cosine window, and applicable rectification fomulas of four-spectrum-line are obtained by using polynomial curve fit function. Comparison with Hanning window, Nuttall 4 terms 5 order window four-spectrum-line interpolation FFT method is carried out by simulation, which verifies this window function has higher precision of analysis at amplitude, phase and frequency. Harmonic analysis for Nanjing Chemical Industrial Park thermoelectric secondary current further verifies the effectiveness of the proposed window function. This work is supported by the State Grid Program of China.