【作者】 夏雪；

【导师】 周林；

【作者基本信息】 重庆大学 ， 电气工程， 2006， 硕士

【摘要】 电能是最重要的能源之一,而电能质量与国民经济的各个部门以及人民的生活密切相关。但是近年来,随着电力电子技术的快速发展,各种电力电子设备、家用电器以及其它非线性负荷的大量使用,使得电网中出现了大量的谐波,造成电力系统谐波污染问题日益严重,也严重影响了电能质量,同时对电力系统安全、稳定、高效地运行形成了威胁。为使电网能够安全运行,将谐波控制在安全的范围内,必须对电网中的谐波进行检测,并根据其结果采取必要的保护措施,严格控制其危害。谐波检测是谐波问题的基础,它也是我们处理谐波危害的根据。本论文对基于小波变换的谐波检测方法进行了研究,主要内容如下:简要分析和探讨了基于傅立叶变换、基于瞬时无功功率理论、基于人工神经网络以及基于小波变换的谐波分析、检测方法基本原理,并对各种方法的优劣进行了比较,同时列举出了各种方法目前的有代表性的主要进展。详细分析和阐述了小波多分辨率分析的基本原理及其在电力系统谐波检测应用的方法,并针对小波MALLAT算法的频率划分原理指出了其在不对称系统谐波检测中的不足。建立了仿真系统,对小波在对称系统中谐波检测进行了仿真,同时针对小波变换在不对称系统谐波检测中的不足,提出了一种基于小波变换的不对称系统谐波检测的新方法,并利用MATLAB建立了仿真系统进行仿真验证,并给出了相应的仿真波形。最后,根据推导出的谐波检测方法,充分利用TMS320LF2407型DSP器件的优势,灵活运用DSP中断功能,用汇编语言开发出了谐波检测的源程序,并建立实际的实验系统对本文提出的基于小波变换的谐波检测方法进行了实验验证,并利用DSP的绘图功能给出了相应的实验波形。从仿真和实验结果来看,小波变换可以比较准确地分离出系统中的谐波,利用DSP等设备,将小波应用于电力系统谐波检测的前景还是比较广阔的。更多还原

【Abstract】 Electricity is one of the most important energy sources, and the quality of electricity is nearly correlative with our lives. However, as the fast development of power electron technology, and the diversified equipment of power electron, home electrical instruments and other no-linear charges greatly increase, harmonics contamination of power system increases severity, and badly affects the quality of electricity and the safe run of power system. To insure the safe run of power system, and limit the harm of harmonics into a safe range, the harmonics of power system must be mearsured then according to its result to take necessary protection action to control its harm. Harmonics detection is the basis of harmonics problem, and is also the foundation to deal with the harm of harmonics. The harmonics detection methods based on wavelet transform are discussed in this paper. The main contents are as follows:Harmonics detection methods based on Fourier transform, instantaneous reactive power theory, artificial neural network and wavelet transform are shortly introduced and discussed, and the advantages and the disadvantages of the whole bag of tricks are compared. The main production of the whole bag of tricks are listed. The basic principium of wavelet transform based on MALLAT Arithmetic and the way to process harmonics detection by wavelet transform are introduced and discussed detailedly, the disadvantage of wavelet transform in the use of harmonics detection of dissymmetrical system is analyzed, too. The simulation system is founded by Matlab6.5, and the harmonics detection based on wavelet transform is simulated. Aimming at the disadvantage of wavelet transform in the use of harmonics detection of dissymmetrical system, a new detection method based on wavelet transform in dissymmetrical system is brought forward and simulated by Matlab, and the corresponding simulated waveforms are given.According to the new harmonic detection methods of this paper, and the signal processing power of TMS320LF2407 DSP(Digital Signal Processing), as well as the ISR(interrupt service routine), the assembler of harmonics detection based on wavelet transform is compiled. The practical detection system is founded to validate the new detection method of this paper, and the experiment waveforms are given by the waveformic function of DSP.According to the simulated and experimental results, the wavelet transform is更多还原