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| 摘要: |
| 为选取一种满足继电保护可靠性和灵敏度要求的滤波算法,对傅里叶变换算法的2种常见改进算法——差分算法和补偿算法进行分析。研究当输入模拟信号叠加谐波和衰减直流分量时,在不同的采样频率下,这2种改进算法的性能和效率。衰减直流分量实时补偿的算法精度较高,但计算量过大。差分算法能在计算量增加不大的情况下,大幅度地提高滤波精度。通过MathCAD仿真计算,分析上述变换的误差,并对比采用全周和半周不同数据窗造成的差异。在一周期24点采样时,即可达到精度和速度的最优效果。考虑兼顾保护的动作速度和测量精度,可以在故障初期采用半周数据窗的傅里叶算法为保护提供数据,后期改用全周数据窗算法。 |
| 关键词: 傅里叶变换,谐波,衰减直流分量 |
| DOI： |
| 分类号:TM77 TM744 |
| 基金项目: |
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| Performance analysis of filtering algorithms based on Fourier transform |
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YAO Liang HU Zaichao HANG Yang
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| Abstract: |
| Two filtering algorithms based on Fourier transform,differential algorithm and compen-sational algorithm,are analyzed to decide which meets the requirements of protection better for both reliability and sensitivity.Under different sampling frequencies,their performances and efficiencies are researched as the input analog signals are added with harmonics and decaying DC.The compensational algorithm has better precision,but its calculation load is too heavy.The differential algorithm enhances greatly the precision without great calculation load increase.With MathCAD simulator,both transform errors are analyzed and the difference between full-wave and half-wave data window is discussed,which shows that,only 24 points per cycle may obtain the optimal results in both accuracy and speed.In consideration of both sampling precision and action speed,Fourier algorithm with half-wave data window is applied in the initial stage of fault to supply data to protection,while full-wave data window in following stages. |
| Key words: Fourier transform,harmonics,decaying DC |
