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instantaneous phase inversion based on an unwrapping algorithm

Applied Geophysics 2020年第1期17卷 124-132,169,170页

作者： Lin Yu-Zhao Li Zhen-Chun Zhang Kai Ding Ren-Wei Jiang Ping Department of Geoscience China University of Petroleum(East China)Qingdao 266580China Shandong Provincial Key Laboratory of Depositional Mineralization&Sedimentary Minearl Shandong University of Science and TechnologyQingdao 266590China College of Science China University of Petroleum(East China)Qingdao 266580China

The full-waveform inversion method is a high-precision inversion method based on the minimization of the misfit between the synthetic seismograms and the observed ***,this method suffers from cycle skipping in the time domain or phase wrapping in the frequency because of the inaccurate initial velocity or the lack of low-frequency ***,the object scale of inversion is affected by the observation system and wavelet bandwidth,the inversion for large-scale structures is a strongly nonlinear problem that is considerably difficult to *** this study,we modify the unwrapping algorithm to obtain accurate unwrapped instantaneous phase,then using this phase conducts the inversion for reducing the strong *** normal instantaneous phases are measured as modulo 2π,leading the loss of true phase *** path integral algorithm can be used to unwrap the instantaneous phase of the seismograms having time series and onedimensional(1 D)signal ***,the unwrapped phase is easily affected by the numerical simulation and phase calculations,resulting in the low resolution of inversion *** increase the noise resistance and ensure the inversion accuracy,we present an improved unwrapping method by adding an envelope into the path integral unwrapping algorithm for restricting the phase mutation points,getting accurate instantaneous *** objective function constructed by unwrapping instantaneous phase is less affected by the local minimum,thereby making it suitable for full-waveform ***,the corresponding instantaneous phase inversion formulas are *** the improved algorithm,we can invert the low-wavenumber components of the underneath structure and ensure the accuracy of the inverted ***,the numerical tests of the 2 D Marmousi model and 3 D SEG/EAGE salt model prove the accuracy of the proposed algorithm and the ability to restore largescale low-wavenumber structures,resp

关键词： instantaneous phase path integral algorithm envelope constraint strongly nonlinear problem

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Vibration-based synchronous sampling and its application in wind-turbine drive-train-condition monitoring

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Clean Energy 2021年第1期5卷 79-92页

作者： Ting Hu Hongyi Wan Huageng Luo National Institute of Clean-and-Low-Carbon Energy China EnergyFuture Science CityChangping DistrictBeijing 102211P.R.China United Power Sida Company China EnergyWest 4th Ring Middle RoadHaidian DistrictBeijing 100039P.R.China Xiamen University 4221–134 Xiang’an South RoadXiang’an DistrictXiamenFujian 361102P.R.China

Utilizing shaft-speed information to analyse vibration signals is an important method for fault diagnosis and condition monitoring of rotating machineries,especially for those running at variable ***,in many cases,shaft-speed information is not always available,for a variety of ***,in most of the measurements,the shaft-speed information is embedded in the vibration response in many different forms,such as in the format of the fundamental shaft-rotation-frequency response and its harmonics,and the gear-meshing-frequency response and its harmonics,*** signal processing can be used to extract the shaft instantaneous speed from the measured vibration *** existing instantaneous shaft-speed-identification methods,a narrow-bandpass filtering technique is used explicitly or *** a complex gearbox system,such as that used in a wind turbine,the gear-meshing-response component could be modulated by many other shaft speeds,due to the configuration of the gearbox or due to the existence of component *** a result,it is very difficult to isolate a single vibration-response component for instantaneous shaft-speed *** this paper,an innovative approach is *** instantaneous shaft speed is extracted based on maxima tracking from the vibration-response spectrogram.A numerical integration scheme is employed to obtain the shaft instantaneous ***-domain synchronous resampling is then applied to the vibration data by using the instantaneous phase *** to the nature of noise suppression in the numerical integration,the accuracy of synchronous sampling is greatly *** proposed approach demonstrates the feasibility and engineering applicability through a controlled laboratory test case and two field wind-turbine *** detailed results and conclusions of this research are presented at the end of this paper.

关键词： wind turbine condition monitoring tacho-less instantaneous speed instantaneous phase synchronous sampling time synchronous averaging

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Single-ended Time Domain Fault Location Based on Transient Signal Measurements of Transmission Lines

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Protection and Control of Modern Power Systems 2024年第2期9卷 61-74页

作者： Jian Luo Yao Liu Qiushi Cui Jiayong Zhong Lin Zhang Chongqing University ChongqingChina Taiyuan University of Technology TaiyuanChina School of Electrical Engineering and with the Liyang Smart City Research Institute Chongqing UniversityChongqing 400044China Electrical Engineering from chongqing University ChongqingChina State Grid Chongqing Electric Power Company Research Institute ChongqingChina

Precise fault location plays an important role in the reliability of modern power *** the in-creasing penetration of renewable energy sources,the power system experiences a decrease in system inertia and alterations in steady-state characteristics following a fault *** existing single-ended phasor domain methods assume a certain impedance of the remote-end system or consistent current phases at both *** problems present challenges to the applicability of con-ventional phasor-domain location *** paper presents a novel single-ended time domain fault location method for single-phase-to-ground faults,one which fully considers the distributed parameters of the line *** fitting of transient signals in the time domain is real-ized to extract the instantaneous amplitude and ***,to eliminate the error caused by assumptions of lumped series resistance in the Bergeron model,an im-proved numerical derivation is presented for the distrib-uted parameter line *** instantaneous symmet-rical components are extracted for decoupling and inverse transformation of three-phase recording *** on the above,the equation of instantaneous phase constraint is established to effectively identify the fault *** proposed location method reduces the negative effects of fault resistance and the uncertainty of remote end pa-rameters when relying on one-terminal data for ***,the proposed fault analysis methods have the ability to adapt to transient processes in power *** comparisons with existing methods in three different systems,the fault position is correctly identified within an error of 1%.Also,the results are not affected by sampling rates,data windows,fault inception angles,and load conditions. Index Terms—Fault location,distributed parameter line model,transient signal,renewable energy,instantaneous phase.

关键词： Fault location distributed parameter line model transient signal renewable energy instantaneous phase

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Extrapolate well logs based on the constrained interpolation algorithm

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Applied Geophysics 2008年第4期5卷 307-313页

作者：刘红伟刘洪秦月霜首皓中国科学院地质与地球物理研究所北京100029 中国地质大学(北京)地质过程与矿产资源国家重点实验室北京100083 中国石油大庆油田有限责任公司大庆163712 中国石油勘探开发研究院北京100083

Based on a detailed analysis of differences between seismic data and well logs, we discuss the problem of matching seismic traces and well logs and present a new matching method based on event search in instantaneous phase which greatly improves seismic resolution. The method is based on flattening events in instantaneous phase to compare the seismic traces to the well log traces with the same phase. We calculate the coefficients using the singular value decomposition method to extrapolate the well logs. As a result, the events in the seismic profile are continuous and match well with well logs. We apply this method to the Mao-2 well in Daqing Oilfield with good results.

关键词： events flattening SVD method instantaneous phase correlation

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Properties of an improved Gabor wavelet transform and its applications to seismic signal processing and interpretation

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Applied Geophysics 2017年第4期14卷 529-542,621页

作者： Ji Zhan-Huai Yan Sheng-Gang School of Marine Science and Technology Northwestern Polytechnical University Xi＇an 710012 China School of Science Xi＇an University of Science and Technology Xi＇an 710054 China.

This paper presents an analytical study of the complete transform of improved Gabor wavelets （IGWs）, and discusses its application to the processing and interpretation of seismic signals. The complete Gabor wavelet transform has the following properties. First, unlike the conventional transform, the improved Gabor wavelet transform （IGWT） maps time domain signals to the time-frequency domain instead of the time-scale domain. Second, the IGW＇s dominant frequency is fixed, so the transform can perform signal frequency division, where the dominant frequency components of the extracted sub-band signal carry essentially the same information as the corresponding components of the original signal, and the sub- band signal bandwidth can be regulated effectively by the transform＇s resolution factor. Third, a time-frequency filter consisting of an IGWT and its inverse transform can accurately locate target areas in the time-frequency field and perform filtering in a given time-frequency range. The complete IGW transform＇s properties are investigated using simulation experiments and test cases, showing positive results for seismic signal processing and interpretation, such as enhancing seismic signal resolution, permitting signal frequency division, and allowing small faults to be identified.

关键词： Seismic signal inverse transform Gabor wavelet transform faults resolutions instantaneous phase

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Extrapolate well logs based on the constrained interpolation algorithm

Extrapolate well logs based on the constrained interpolation...

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中国科学院地质与地球物理研究所2008学术年会

作者： Liu Hongwei,Liu Hong,Qin Yueshuang,and Shou Hao 1.Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China. 2.State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing,100083 3.The Exploratory development Institute of Daqing Oilfield Limited Liability Company,Daqing 163712,China. 4.Research Institute of Exploration and Development of Chinese Petroleum,Beijing 100083,China.

Based on a detailed analysis of differences between seismic data and well logs, we discuss the problem of matching seismic traces and well logs and present a new matching method based on event search in instantaneous phase which greatly improves seismic *** method is based on flattening events in instantaneous phase to compare the seismic traces to the well log traces with the same *** calculate the coefficients using the singular value decomposition method to extrapolate the well *** a result,the events in the seismic profile are continuous and match well with well *** apply this method to the Mao-2 well in Daqing Oilfield with good results.

关键词： events flattening SVD method instantaneous phase correlation

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