基于加窗插值和ZoomFFT的电网宽频信号自适应测量方法

Adaptive Measurement Method for Wide-band Signal in Power Grid Based on Windowed Interpolation and ZoomFFT

随着电力电子化电网的不断发展,日趋宽频化、复杂化的电网信号对测量算法的自适应性和精度提出了更高的要求。为此,提出了一种基于加窗插值和复调制细化谱分析的宽频信号自适应测量方法。基于主、旁瓣特性和插值校正过程对窗函数进行选型后,根据信号频谱的主瓣干扰情况,分别基于4项5阶Nuttall窗双谱线插值算法和复调制细化谱分析法进行针对性的测量。最后,通过仿真对比及实测数据分析验证了所提方法的测量精度和稳定性,结果表明其有效实现了0~2.5 kHz范围内谐波和频率相近间谐波的高精度自适应测量,更高的测量精度和更低的运算代价使其能够满足电力电子化电网的测量需求。

With the continuous development of power-electronized power grid,the increasingly wide-band and complex power grid signals demand higher adaptability and accuracy of measurement algorithms.Therefore,an adaptive measurement method for wideband signals based on windowed interpolation and multiple modulation zoom spectrum analysis is proposed.After selecting the window function based on the characteristics of main and side lobe and interpolation correction process,according to the main-lobe interference of the signal spectrum,the double-spectral-line interpolation algorithm based on four-term fifth-order Nuttall window,and multiple modulation zoom spectrum analysis are separately used for targeted measurements.Finally,the measurement accuracy and stability of the proposed method are verified by simulation comparison and measured data analysis.The results show that the high-accuracy adaptive measurement of harmonics and inter-harmonics with similar frequencies in the range of 0~2.5 k Hz is effectively realized.Higher measurement accuracy and lower computation cost enable it to meet the measurement requirements of a power-electronized power grid.