电网电压监测设备在监测运行设备的电流电压波形时通常采用谐波分析法，针对传统FFT谐波分析法在电网频率波动时谐波测量会产生栅栏效应和频谱泄漏的问题，在研究余弦窗特性的基础上提出了一种改进3项余弦窗。通过频谱衰减曲线与传统余弦窗对比，采用基于数据样本的非线性拟合方法，拟合出了改进窗插值算法的谐波幅值相位修正系数，使改进窗插值算法能实际应用于谐波测量。通过谐波测量仿真对比，验证了加改进余弦窗的谐波测量准确度更高。%Grid voltage monitoring equipments in the monitoring current and voltage waveforms of operating equipment commonly use the method of harmonic analysis. To solve the problem that traditional FFT harmonic analytical algorithm produces fence effect and spectrum leakage when the grid frequency shifts,an improved method of three cosine windows is proposed on the characteristic research of cosine window. Comparison to traditional windows through the spectrum attenuation curve shows superiority, a nonlinear fitting method based on the data sample is used to calculate correction factors for harmonic amplitude and frequency of the improved cosine window interpolated algorithm. With the corrected factors,the improved algorithm can be applied to real harmonic measure. Contrast to harmonic simulation results,the improved cosine window shows higher accuracy.
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