文档介绍：东北电力大学硕士学位论文基于改进形态滤波器和HHT的电力系统谐波/间谐波检测新方法姓名:贺健伟申请学位级别:硕士专业:电力系统及其自动化指导教师:张宇辉 20080301 摘要摘要随着电力系统的发展以及非线性电力元件的大量应用,如主要的间谐波源一一电弧炉、加热控制器和整流装置等使电网中谐波和间谐波问题变得较为突出, 给电网和用电设备造成了危害。为了减小谐波的危害,多种谐波检测和谐波补偿的方法相继提出,而目前探讨谐波检测的方法大都单独局限在时域或频域内,并用于间谐波背景下谐波实时补偿的方法又存在着局限性,因此有必要对间谐波问题作进一步研究。本文提出了一种基于数学形态学和HHT的谐波和间谐波检测的新方法,首先, 通过对数学形态变换和数学形态滤波器特性作了细致的研究,并且针对其结构元素选取上的缺陷和统计偏移现象,对现有的数学形态滤波器结构元素选取上的缺陷进行了改进。利用数学形态滤波器在时域的低通特性对待分析的信号作消噪处理。然后,对消噪后的信号进行EMD分解得到一组平稳的IMF分量,并且对每个IMF分量进行Hilbert变换可以准确地得到其瞬时频率和瞬时幅值。从而实现了噪声背景下的谐波、间谐波的检测。大量的仿真结果表明:改进的数学形态滤波器较传统的滤波器能更有效的抑制多种噪声,除了可以抑制加性噪声之外,还在抑制正、负脉冲噪声上具有良好的效果。HHT是一种完全自适应时频分析方法,通过其EMD分解将待分析的信号平稳化处理得到各个频率分量的单频信号,使Hilben变换结果具有实际物理意义,实现了信号中谐波、间谐波的参数准确提取。关键词:改进的形态滤波器:消噪:谐波/问谐波:EMD分解:Hilbert变换东北电力大学工学硕士学位论文 Abstract With thedevelopment ofmodem Power System and application ofnonlinear electric elements,for example,electric arc furnaces,converters,induction motors and SO on,harmonics have changed into plex quegion andthe situation have endangered Power System and electricequipments,in which inter-harmonics and sub—harmonicsareimportant factors. To reduce these harms,various methods of harmonics detection and pensation were ,these methods areonly localized infrequency field or time fieldand the methods pensation ininter-harmonics are not satisfied. Therefore,it isnecessary tostudy how toanalyze inter-harmonics ponent extraction under inter-harmonics background furthermore. Anew method based onMathematical Morphology and HHT isproposed todetectthesignal with harmonic and inter· filterismodified asto selection of structure elements via doing fme researching forMM transformation and disadvantage ofselection structure element and signal isde·noisedthough character oflow-passing ,the signal isEMD to obtain a series ofIMF,and every IMF is hilbert-transformed togetamplitude andfrequency method realized detection of harmonic and inter-harmonic ontheground ofnoise on thereal sense. La