2014,50(22)
1 引言
接触网是电气化铁路一种特殊形式的供电线路,是
电力机车良好受流和安全运行的关键,由于其安装高度
低和无备用的特点,因此是电气化铁路中的薄弱环节
[1]
。
接触网事故约占牵引供电总事故的 60%~80%,其中因
绝缘导致的故障占有较大比例
[2]
。受绝缘子工作环境的
限制,要完全避免绝缘子闪络是不可能的,只能采取措
施来降低绝缘子污闪事故发生的概率,主要途径是对绝
缘子状态实行实时监测。由于泄漏电流是气候、电压、
污秽三要素最终作用结果,且便于在现场连续测量,选
基于改进 EMD 的接触网绝缘子泄漏电流去噪
张友鹏,周 郁,赵珊鹏,王思华,董海燕
ZHANG Youpeng, ZHOU Yu, ZHAO Shanpeng, WANG Sihua, DONG Haiy an
兰州交通大学 自动化与电气工程学院,兰州 730070
School of Automation & Electric al Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
ZHANG Youpeng , ZHOU Yu, ZHAO Shanpe ng, et al. De-no ising of insulator leakage cur ren t of overhead contact
system based on improved EMD. Computer Engineering and Applications, 2014, 50(22):211-216.
Abstract:There is a larg e number of noise when insulator leakage current of overhead contact system is taken. EMD
(Empirical Mode Decomposition)has the problems of end effect and illusive component in actual use. In this paper, similar
extrema extension method and the ratio of power method are used to solve the problems e xisting in EMD, and then, wavelet
threshold is combined to de-noise the leakage current. Improved EMD threshold de -noising method and wavelet threshold
de-noising met hod are used respec tively to remove the noise from both the simulated leakage current and the leakage current
gathered i n the high volt age experiment . Estimate the results through the analysis and comparison of three characteristics
of the signal pre-and-post de -no ised, including effective value, the amplitud e value ratio of triple-harmonic to fundamental
and s ignal-to-noise ratio(SNR). It is shown that simil ar extrema extension method and the r atio of power method can
solve the problems of end effect and illusive compo nent, the de-noising result of de- noisi ng method ba sed on improved
EMD threshold method is better than wavelet threshold method. At the same time, impro ved EMD threshold method is
self-adaptive, therefore, is suitable to dirty wet insulator leakage current of overhead contact system de-noising.
Key wo rd s:overhead contact system insulator; leakage current; improved Empirical Mode Decomposit ion(EMD); signal
de-noi sing
摘 要:采集接触网绝缘子泄漏电流时存在大量干扰,且使用经验模态分解(Empirica l Mode Dec omposition,EMD)
方法去噪时存在端点效应和虚假分量的问题。提出利用类似极值延拓法和功率比值法(The Ra tio of Power,TRP)
解决 EMD 存在的上述问题,结合小波阈值方法对泄漏电流进行去噪。选择小波阈值去噪作为对比,对泄漏电流仿真
模型和高压实验采集的泄漏电流进行去噪处理。通过去噪前后的有效值、三次谐波和基波幅值之比和信噪比对去噪
效果进行评价。结果表明类似极值延拓法和 TRP法可有效解决端点效应和虚假分量问题,改进 EMD 阈值去噪方法去
噪效果优于小波阈值去噪。改进 EMD阈值去噪方法具有自适应性,适用于污湿情况下的绝缘子泄漏电流去噪处理。
关键词:接触网绝缘子;泄漏电流;改进经验模态分解阈值;信号去噪
文献标志码:A 中图分类号:U225.8 doi:10.3778/j.issn.1002-8 331.1306-0152
基金项目:铁道部科技研究开发计划重点课题(No.2012J007-C);教育部中央高校基本科研业务费专项资助项目(No.212099);兰州
交通大学青年科学基金项目(No.2013038)。
作者简介:张友鹏(1965—),男,教授,博士生导师,研究方向为高电压与绝缘技术研究;周郁(1987—),男,硕士研究生,研究方向
为高电压与绝缘技术研究;赵珊鹏(1983—),男,工程师,研究方向为高电压与绝缘技术研究;王思华(1968—),男,副
教授,研究方向为高电压与绝缘技术研究;董海燕(1987—),女,博士研究生,研究方向为高电压与绝缘技术研究。
E-mail:594720158@qq.com
收稿日期:2013-06-15 修回日期:2013-10-08 文章编号:1002-8331(2014)22-0211 -06
C omputer Engineering and Applications 计算机工程与应用
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