论文标题:基于抗混叠小波理论的电力系统谐波检测与抑制研究
Study on Harmonic Detection & Suppression in Power System Based on Anti-aliasing Wavelet Theories
论文作者
论文导师 陈光（礻禹）,论文学位 博士,论文专业 测试计量技术及仪器
论文单位 电子科技大学,点击次数 83,论文页数 131页File Size4563K
2005-12-01论文网 http://www.lw23.com/lunwen_741198997/
Power System; Wavelet Transform; Instantaneous Reactive Power Theory; Wavelet Aliasing; Harmonic Detection; Harmonic Suppression
电力系统谐波一直是一项富有挑战性的研究课题。谐波检测与抑制是谐波问题中的核心内容，是谐波问题研究的主要依据和最终目标。由于谐波固有的非线性、随机性、分布性、非平稳性和影响因素的复杂性等特征，许多常规的检测方法难以对谐波进行准确测量，因此研究新的谐波检测与抑制方法，具有重要的理论和实用意义。小波变换因其良好的时频局部化特性，可用来进行谐波检测。自从1996年IEEE在第7届国际谐波学术会议上倡议将小波理论应用到电力系统以来，小波检测方法在谐波测量领域得到长足的发展。然而，目前几乎所有的小波函数都存在小波混叠问题，虽然许多文献都表明基于小波变换的谐波检测方法优于传统的谐波检测技术，但由于没有采取混叠抑制措施，不能满足精度和鲁棒性的要求。本论文基于抗混叠小波理论，深入研究了电力系统谐波的检测抑制方法。作者的主要工作有如下3个方面： (1) 研究了小波混叠误差估计与混叠原因分析 利用Shannon采样定理和Walter采样定理，推导并估算了小波变换总误差和小波混叠误差；从多种角度阐明了小波混叠产生的物理本质、幅频特性原因和滤波器设计局限；举例说明了小波混叠现象及混叠对谐波检测的影响。 (2) 提出了三种抗混叠小波变换谐波检测方法 ①基于频域内插抗混叠小波变换的谐波检测方法。选择分频严格的Shannon小波作为变换母函数，采用频域内插算法来抑制小波混叠和Gibbs现象，并利用线性调频Z变换进行快速求解。 ②基于混叠补偿抗混叠小波变换的谐波检测方法。在既有的滤波器结构上，增加混叠补偿环节，注重小波分解分量的混叠抑制，将谐波信号分解成不同频带的子频带信号，再利用连续小波变换提取谐波特征。 ③基于内插优化抗混叠小波包变换的谐波检测方法。在既有的滤波器结构上，增加一些内插的高低通滤波器，采用权系数来平衡两个优化准则，并利用优化算法求解内插滤波器系数。设计的抗混叠滤波器，同时兼顾了混叠抑制与信号保持两方面因素，克服了传统小波滤波器仅考虑信号精确重建和总体抗混叠而带来的固有缺陷。
Power system harmonic issue is a challenge topic in the world. As core of harmonic issues, harmonic detection and suppression is the main basis and final goal of harmonic studies. Owing to the inherent nonlinearity, randomness, distributing, nonstationarity and complexity of influencing factor on power system harmonics, many conventional detection techniques can"t acquire accurate harmonic identification, so it is excellent valuable in theory and practice to investigate new detection and suppression methods. Because of excellent time-frequency localization characteristics, wavelet transform (WT) can be used to detect harmonics. Since IEEE proposed applying WT to harmonic analysis in the 7~(th) international harmonic conference in 1996, WT based methods gained rapid development in harmonic detection. However, owing to aliasing within almost all the existed wavelets, even though it is shown that wavelet-based methods are superior to the traditional detection techniques, they can"t satisfy the accurateness and robustness requirement. This dissertation deeply studies harmonic detection and suppression technology based on anti-aliasing wavelet theories. Author"s main work concentrates on three aspects as follows:(1) Wavelet aliasing error estimation and aliasing reason analysisWT total error and aliasing error is estimated by using Shannon sampling theory and Walter sampling theory, and aliasing cause is clarified in many ways such as physics essence, magnitude-frequency characteristics and filter design limitation. In addition, aliasing phenomenon and aliasing harm is illustrated.(2) Three anti-aliasing wavelet based harmonic detection methods① Harmonic detection method based on frequency-domain interpolation anti-aliasing wavelet transform. Shannon wavelet function which can divide frequency-band strictly is selected as generating function; the frequency-domain interpolation algorithm is used to cancel wavelet aliasing and Gibbs phenomenon; Chirped Z transform is used to achieve fast computation.
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