| 引用本文: | 袁石良,董杰,徐志强,等.基于频率测量值的相量及电气量的DFT修正算法[J].电力系统保护与控制,2018,46(14):122-127. |
| YUAN Shiliang,DONG Jie,XU Zhiqiang,et al.A correction DFT algorithm of phasor and electric parameters based on frequency measurement[J].Power System Protection and Control,2018,46(14):122-127 |
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| 摘要: |
| 为解决频率偏移时电力系统相量及电气量的测量误差大的问题，提出了一种改进的离散傅里叶(DFT)修正算法。建立了相量的实部、虚部与幅值、初相角、频率偏移量之间的函数关系式，根据此关系式得到实部、虚部与频率之间所满足的一个恒等式。在频率已知条件下计算出修正后的相量幅值和相角，进一步推导出了修正后的相量实部与虚部，最后得到其他电气量的修正算法。仿真结果表明，当系统频率偏移时，在信号为纯正弦信号，或者含有高次谐波及随机噪声等情况下，算法均可有效地提高相量及电气量的计算精度。同时，该算法对采样频率和频率误差不敏感，计算量小，不增加额外的延迟时间。 |
| 关键词: 非同步采样 频率 相角误差 幅值误差 修正 |
| DOI：10.7667/PSPC171027 |
| 分类号: |
| 基金项目: |
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| A correction DFT algorithm of phasor and electric parameters based on frequency measurement |
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YUAN Shiliang1,DONG Jie2,XU Zhiqiang1,SONG Meijie3
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(1. China University of Mining & Technology (Beijing), Beijing 100083, China;2. Beijing Sifang Automation Co., Ltd, Beijing 100085, China;3. Guilin University of Aerospace Technology, Guilin 541004, China)
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| Abstract: |
| To solve the problem of the measurement error of phasor and electrical parameters in the power system when frequency offset, an improved DFT correction algorithm is proposed. The function relation between the real part, the imaginary part of the phase and the amplitude, the initial phase angle, the frequency offset is established. According to this relation expression, the real part, the imaginary part and the frequency offset satisfy an identities. Therefore, the correction algorithm of the amplitude and phase angle of the phase can be obtained under the known frequency. Further, the corrected real and imaginary parts of the phasor are derived. Finally, a correction algorithm for other electrical quantities is obtained. Simulation results show that when the system frequency is shifted, the algorithm can effectively improve the accuracy of phasor and electrical quantity when the signals are pure sinusoidal signals or the signals with higher harmonics and random noise. Meanwhile, the algorithm is insensitive to the sampling frequency and frequency error, and the algorithm has a small amount of calculation and does not increase the extra delay time. |
| Key words: asynchronous sampling frequency phase angle error amplitude error correction |
