【作者】 曹国剑；

【导师】 黄纯；

【作者基本信息】 湖南大学 ， 电力系统及其自动化， 2004， 硕士

【摘要】 离散傅立叶变换(DFT)是电参量微机检测中应用最为广泛的一种算法。但由于非同步采样以及时、频域有限化和离散化等原因，常规DFT在对电参量信号进行频谱分析时会产生较大误差，测量结果难以满足高检测精度的要求。频谱校正理论近年来广泛应用于机械振动信号分析及故障诊断等领域，但在电力系统，特别是在电参量测量中的应用鲜为报道。因此，进一步开展频谱校正理论在电参量测量领域中的应用研究，补充和发展电参量检测的理论和方法，具有重要的理论意义和实用价值。 本文从提高电参量检测精度的角度出发，首先回顾了电参量检测方式的发展历程，介绍了常见电参量检测方法的特点以及提高DFT算法分析精度的多种改进方法，阐明了本文的研究背景；其次对傅立叶变换的基本理论、基本形式以及实际应用中应注意的问题进行了详细的阐述，对传统的基于加窗OFT的电参量检测方法产生误差的原因进行了深入分析，提出了频谱泄漏误差的解析表达式及校正方法的数学模型。进而对多种离散频谱校正方法的基本原理进行了数学推导，给出了实现具体算法的详细步骤，对各种方法的特点及其在电参量检测技术中的适用条件作了探讨和比较；进而针对典型电力系统信号，借助MATLAB语言对传统DFT算法和本文引入的多种校正方法进行仿真，通过对仿真的结果和算法复杂度的分析和对比，验证了频谱校正方法的有效性和优越性，阐述了各算法的特性及优缺点，同时对如何进一步扩展频谱校正方法的应用场合进行了初步探讨：基于提出的新检测原理，提出了一种新的微机型自动准同期并列装置电压参数的测量算法，介绍了该算法在实际装置中的实现步骤和方案；最后对全文工作做了总结，指出了研究的不足，对如何进一步提高校正方法的精度以及电参量检测技术的发展趋势做出了展望。更多还原

【Abstract】 Discrete fourier transform (DFT) is one of the most popular methods applied in computer-based measurement of electric parameters. However, the non-synchronous sampling, finiteization, and discretization of time-domain and frequency-domain during the spectrum analysis of electric signals cause measuring errors, which makes it difficult to satisfy the request of high detection precision. Spectrum correction theory is applied extensively in the field of machinery vibration signal analyzing and faults diagnose in recent years, but its application is seldom reported in power system, especially in the field of electric parameters measurement. Therefore, it has important theoretical significance and practical value to engage the research and supplement the detection method of electric parameters.From the viewpoint of improving the detection precision of electric parameters, this paper first reviews the development process of detection mode, and introduces the character of the usual electric parameters detection method and different kinds of improving method based on DFT algorithm to enhance the analysis precision, and elucidates the research background. Secondly this paper details the basic theory, form of fourier transform, and the problems which must be paid attention to in the practical application. The reasons of the error caused by the traditional electric parameter detection methods base on the windowed DFT are thoroughly analyzed. The analytic representation of the error caused by spectrum leakage and the numerical model of the correcting method are proposed. Mathematical derivation of the basic principle of many kinds of discrete spectrum correction method has been carried on. The detailed steps to realize the concrete algorithm are given in this paper. The characters of various methods and its applying condition in the electric parameters detection are discussed and compared. With the help of MATLAB language, simulation on detecting typical power system signals has been done by applying both the traditional DFT algorithm and the methods proposed in this paper. The analysis and comparison of the simulating results verifies the validity and advantage of the spectrum correction methods. The characters, advantages, and shortcomings of each algorithm are elaborated. At the same time, the problem about how to further expand the application occasion of the spectrum correction methods is discussed preliminarily. Based on the new detection principle, this paper designs a new measuring algorithm to measure the voltage parameters of a microcomputer based automatic quasi-synchronizationparalleling device, and introduces the realization steps and schemes of this algorithm. Finally the paper summarizes the research work of the whole paper and points out the flaws. The prospects about how to further improve the precision of correcting method and the developmental trend in the future are discussed.更多还原