期刊文献+
共找到3篇文章
< 1 >
每页显示 20 50 100
基于时频域转换法的配网电缆冷缩中间接头受潮诊断 被引量:12
1
作者 王子健 周凯 +3 位作者 朱光亚 梁钟颖 王子康 傅尧 《高电压技术》 EI CAS CSCD 北大核心 2022年第6期2178-2186,共9页
针对配网电缆冷缩中间接头由于受潮缺陷演变导致电缆故障频繁发生的问题,提出了基于频域和时域转换分析的电缆中间接头受潮诊断实用方法,弥补了单一频域反射法(FDR)在接头受潮检测方面的不足。首先介绍了冷缩接头典型结构,通过仿真及实... 针对配网电缆冷缩中间接头由于受潮缺陷演变导致电缆故障频繁发生的问题,提出了基于频域和时域转换分析的电缆中间接头受潮诊断实用方法,弥补了单一频域反射法(FDR)在接头受潮检测方面的不足。首先介绍了冷缩接头典型结构,通过仿真及实验研究了冷缩接头受潮电容变化规律,阐述了频域反射法的基本原理,并分析了该方法在检测局部缺陷或接头受潮时存在的不足,提出采用时频域转换对接头受潮缺陷进行联合诊断的方法,该方法首先采用FDR检测对接头位置进行准确定位,然后基于时域波形恢复技术通过提取接头位置处左右时域波形特征来对接头受潮情况进行判断。基于时频转换分析法对包含不同受潮程度接头的电缆进行仿真分析和实测,结果表明:界面受潮将使冷缩接头单位电容增大,进而影响该处特性阻抗,严重受潮冷缩接头单位电容值高于电缆本体单位电容值,该处时域恢复波形呈现“左负右正”的特征。所提的时频转换分析法可以实现对配网电缆受潮冷缩接头的有效定位诊断。 展开更多
关键词 配电电缆 冷缩式中间接头 受潮诊断 单位电容 时频转换分析
下载PDF
Study of seismic spectrum decomposition based on CEEMD 被引量:3
2
作者 LIU Shuang HAN Liguo 《Global Geology》 2014年第2期120-126,共7页
Empirical mode decomposition( EMD) is a powerful tool of time-frequency analysis. EMD decomposes a signal into a series of sub-signals,called Intrinsic mode functions( IMFs). Each IMF contains different frequency comp... Empirical mode decomposition( EMD) is a powerful tool of time-frequency analysis. EMD decomposes a signal into a series of sub-signals,called Intrinsic mode functions( IMFs). Each IMF contains different frequency components which can deal with the nonlinear and non-stationary of signal. Complete ensemble empirical mode decomposition( CEEMD) is an improved algorithm,which can provide an accurate reconstruction of the original signal and better spectral separation of the modes. The authors studied the decomposition result of a synthetic signal obtained from EMD and CEEMD. The result shows that the CEEMD has suitability in spectrum decomposition time-frequency analysis. Compared with traditional methods,a higher time-frequency resolution is obtained through verifying the method on both synthetic and real data. 展开更多
关键词 EMD spectrum decomposition time-frequency analysis
下载PDF
The Simulation and Characteristic Study of Wind Velocity for Long-Span Structures
3
作者 周岱 马骏 +1 位作者 吴筑海 陈思 《Journal of Shanghai Jiaotong university(Science)》 EI 2004年第4期41-46,共6页
The new technique that combines wave superposition with the fast Fourier transformation was introduced to simulate the nodal three-dimension relevant wind velocity time series of spatial structures. The wind velocity ... The new technique that combines wave superposition with the fast Fourier transformation was introduced to simulate the nodal three-dimension relevant wind velocity time series of spatial structures. The wind velocity field where the spatial structure is located is assumed to be homogeneous. The wind’s power spectral density is divided into frequency spectral function and coherency function and the spectral functions are transformed as the superposition coefficients. The wavelet analysis has excellent localized characters in both time and frequency domains, which not only makes wind velocity time series analysis more accurate, but also can focus on any detail of the objective signal series. The discrete wavelet transformation was adopted to decompose and reconstruct the discrete wind velocity time series. The stability of wavelet analysis for the wind velocity time series was also proved. 展开更多
关键词 spatial structure wind velocity simulation wavelet analysis wave superposition time-frequency analysis
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部