DOC《毕业设计（论文）》

毕业设计(论文) 题目基于HHT的暂态电能质量 多扰动信号的检测 基于HHT的暂态电能质量多扰动信号的检测 摘要传统时频分析方法在处理复杂的故障信号时存在一定的局限性,已经不能满足电力系统发生故障和复杂扰动时的电力信号的实时分析的需要.

本文应用Hilbert-Huang变换(HHT)进行电能质量暂态多扰动信号的分析与研究. Hilbert-Huang变换(HHT)是一种新的非平稳信号处理技术,该方法由经验模态 分解(EMD)与Hilbert谱分析两部分组成.任意的非平稳信号首先经过EMD方法处理后被分解为一系列具有不同特征尺度的数据序列,每一个序列称为一个固有模态函数(IMF),然后对每个IMF分量进行Hilbert谱分析得到相应分量的Hilbert谱,汇总所有Hilbert谱就得到了原信号的谱图.该方法从本质上讲是对非平稳信号进行平稳化处理,将信号中真实存在的不同尺度波动或趋势逐级分解出来,最终用瞬时频率和能量来表征原信号的频率含量. 本文研究了基于HHT的暂态电能质量扰动检测方法,介绍了HHT的基本原理和利用HHT检测电能质量多扰动信号的实现方法.仿真试验表明该方法可以实时检测扰动的起止时刻,持续时间和扰动幅度,适用于电能质量多扰动的监测和辨识系统. 关键词:HHT、电力系统、电能质量、扰动检测、MATLAB仿真 Abstract There are some limitations in traditional methods of time.Frequency analysis while deal with complex fault signals,and it is unable to meet with the real-time signal analysis in large power system disturbances and power failure.In this paper,Hilbert―Huang Transform(HHT) was used to analysis the transient disturbance signal of power system. Hilbert-Huang Transform(HHT) is a new non-stationary signal processing technology,including the Empirical Mode Decomposition(EMD) and Hilbert spectral analysis.In this method,arbitrary non-stationary signals was divided into a series data sequence with different characteristic scales after the first EMD treatment,each sequence is called an intrinsic mode function(IMF),and then each IMF component gained corresponding the Hilbert spectrum though Hilbert spectrum analysis,a summary of all Hilbert spectrum assembled to the spectra of the original signal.In essence,this method is a stable processing for non-stationary signal,which decomposed the different fluctuations or trends in the signal in rum,and represented the frequency content of the original signal using the final instantaneous frequency and energy. This paper study a method to detect power quality disturbances based on the HHT,in which the principle and the realization of the HHT and the realization of power quality disturbances used by the amplitude matrix of HHT of signals age introduced.The results show that this method can localize the disturbance precisely,so it is suitable to the monitoring and classification system for power quality disturbance. Keywords: HHT, power system, power quality, disturbances detect, MATLAB simulation 目录第1章绪论11.1课题研究背景及意义

1 1.2电能质量及其多扰动

2 1.2.1电能质量

2 1.2.2 电能质量多扰动

4 1.3 HHT及其研究现状

4 1.4本论文主要工作

7 第2章Hilbert-Huang变换(HHT)的基本原理

8 2.1 Hilbert-Huang变换(HHT)概述

8 2.2 瞬时频率

9 2.3 固有模态函数及其相关概念

10 2.3.1 特征尺度参数

10 2.3.2 固有模态函数

11 2.4 三次样条差值

12 2.5小结

13 第3章 基于HHT的电能质量多扰动检测的实现及仿真实例分析