The New Methodology of Diagnosis for Transformer Inter-Turn Short Circuit Based on Wavelet Analysis

2014 ◽  
Vol 672-674 ◽  
pp. 1155-1158
Author(s):  
Yu Sheng Quan ◽  
Ning Chen ◽  
Zi Jian Wang ◽  
Pu Xin Shi
Keyword(s):  
High Frequency ◽  
Short Circuit ◽  
Frequency Component ◽  
Diagnostic Methods ◽  
High Frequency Component ◽  
Transformer Winding ◽  
Frequency Components ◽  
Circuit Fault Diagnosis ◽  
Experimental Data Analysis ◽  
Transformer Core

Based on the large number of experimental data analysis and processing, a new inter-turn short circuit transformer diagnostic methods is proposed. In this paper, take the grounding current of transformer core as the signal source. Using wavelet multi-resolution technology the signal wavelet multiscale decomposition, we can get high frequency components of the signal. Achieve short-circuit fault diagnosis between transformer winding turns by comparing the number of the high-frequency component contained in different signals in the decomposition of the same scale.

Research on Detection Method of Transformer Interturn Short Circuit Based on Wavelet Analysis

2014 ◽  
Vol 521 ◽  
pp. 358-361
Author(s):  
Yu Sheng Quan ◽  
Zong Cheng Zhang ◽  
Guang Chen ◽  
Dai Juan Wang
Keyword(s):  
High Frequency ◽  
Short Circuit ◽  
Frequency Component ◽  
Diagnostic Methods ◽  
High Frequency Component ◽  
Transformer Winding ◽  
Ground Current ◽  
Frequency Components ◽  
Circuit Fault Diagnosis ◽  
Experimental Data Analysis

Distribution transformer is an important device in the power supply system, once its failure can cause power outages. According to statistics, 70% -80% of the transformer accident was caused by a short circuit between the transformer turns. Based on the large number of experimental data analysis and processing, a new inter-turn short circuit transformer diagnostic methods is proposed. In this paper, the ground current of transformer core as the signal source, Using wavelet multi-resolution technology the signal wavelet multiscale decomposition, the decomposition of different signals of the same scale, get the high frequency components of the signal, achieve short-circuit fault diagnosis between transformer winding turns by comparing the number of the high-frequency component contained in different signals in the decomposition of the same scale. To illustrate the effectiveness of the method, the paper through a series of experiments and data processing, verify the effectiveness and feasibility of the method.

A Modified DFT-Based Channel Estimation Method for OFDM-RoF System

2014 ◽  
Vol 989-994 ◽  
pp. 3521-3525
Author(s):  
Li Qun Huang ◽  
Peng Zhang ◽  
Guang Yang
Keyword(s):  
Channel Estimation ◽  
High Frequency ◽  
Estimation Method ◽  
Frequency Component ◽  
High Frequency Component ◽  
Improved Method ◽  
Frequency Components ◽  
Influence Of Noise ◽  
Changing Rate ◽  
Better Than

In this paper, we present a modified discrete Fourier transform (DFT)-based channel estimation method. The conventional DFT-based method will produce additional high frequency component in the channel impulse response, and degrade the accuracy of channel estimation. The modified algorithm can eliminate additional high frequency components by extending the LS estimate in frequency domain with a symmetric signal of its own, and selects the useful paths by calculating the changing rate of energy. Thus, the proposed algorithm become more accurate. The simulation results show the new algorithm can reduce the influence of noise on channel estimation efficiently, and the performance of the improved method is better than the LS and conventional DFT algorithm.

Study on Ship Structural Hydroelasticity and Fatigue Assessment in Irregular Seaways

2013 ◽  
Author(s):  
Jung-Hyun Kim ◽  
Yonghwan Kim ◽  
Yooil Kim ◽  
Kyong-Hwan Kim
Keyword(s):  
High Frequency ◽  
Superposition Principle ◽  
Three Dimensional ◽  
Frequency Component ◽  
High Frequency Component ◽  
Fatigue Assessment ◽  
Hydroelastic Analysis ◽  
Frequency Components ◽  
Fully Coupled ◽  
Ship Hydroelasticity

This paper introduces an analysis of ship hydroelasticity for a fatigue assessment of ship structural design. In this study, the hydroelastic analysis for springing and whipping is carried out by using a fully coupled three-dimensional BEM-FEM approach with two-dimensional slamming theoreis, and a sequential fatigue assessment is performed. The fatigue damage is decomposed to wave frequency and high frequency components. Furthermore, the high frequency component is again decomposed to 1st harmonic springing, super harmonic springing and whipping contributions. This decomposition is achieved using a modal superposition principle. Amount of the contributions are compared in irregular sea states.

scholarly journals Stress Recovery Effects of High- and Low-Frequency Amplified Music on Heart Rate Variability

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yoshie Nakajima ◽  
Naofumi Tanaka ◽  
Tatsuya Mima ◽  
Shin-Ichi Izumi
Keyword(s):  
Heart Rate ◽  
White Noise ◽  
High Frequency ◽  
Low Frequency ◽  
Frequency Component ◽  
High Frequency Component ◽  
Stress Recovery ◽  
Recovery Ratio ◽  
Autonomic Responses ◽  
Frequency Components

Sounds can induce autonomic responses in listeners. However, the modulatory effect of specific frequency components of music is not fully understood. Here, we examined the role of the frequency component of music on autonomic responses. Specifically, we presented music that had been amplified in the high- or low-frequency domains. Twelve healthy women listened to white noise, a stress-inducing noise, and then one of three versions of a piece of music: original, low-, or high-frequency amplified. To measure autonomic response, we calculated the high-frequency normalized unit (HFnu), low-frequency normalized unit, and the LF/HF ratio from the heart rate using electrocardiography. We defined the stress recovery ratio as the value obtained after participants listened to music following scratching noise, normalized by the value obtained after participants listened to white noise after the stress noise, in terms of the HFnu, low-frequency normalized unit, LF/HF ratio, and heart rate. Results indicated that high-frequency amplified music had the highest HFnu of the three versions. The stress recovery ratio of HFnu under the high-frequency amplified stimulus was significantly larger than that under the low-frequency stimulus. Our results suggest that the high-frequency component of music plays a greater role in stress relief than low-frequency components.

scholarly journals GEOLOGICAL HETEROGENEITY OF A SEDIMENTARY COVER OF THE PECHORA PLATE ACCORDING TO HYDROMAGNETIC SURVEY

2019 ◽  
Vol 47 (1) ◽  
pp. 161-173
Author(s):  
Yu.V. Brusilovsky ◽  
A.N. Ivanenko
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Sedimentary Cover ◽  
Low Frequency ◽  
Frequency Component ◽  
High Frequency Component ◽  
Spectral Structure ◽  
Magnetic Survey ◽  
Frequency Components ◽  
Buried Paleochannels

In August–September, 2018 in the Pechora Sea during the 38th flight of NIS “Academician Nikolay Strakhov” complex geologic-geophysical researches were conducted. Magnetic survey was carried out along with seismic profiling where as the radiator of elastic fluctuations the electrospark Sparker radiator was used. The group of a sea magnetometry was faced by a problem of mapping of the top layer of a sedimentary cover, including allocation of zones of development of thin deposits, buried paleochannels, zones of jointing and geological explosive violations. Hydromagnetic survey and interpretation of the received materials was as a result executed that allowed to estimate spectral structure of the abnormal magnetic field (AMF) and to allocate three frequency components to which there corresponds the deep range of sources of the field. Leaning on the received estimates of depths, and comparing them to the description of wells, also temporary bindings for the allocated deep ranges of sources of magnetic field were defined. High-frequency component, there corresponds the arrangement of sources of AMF in the topmost part of a section. The top edges of sources lie in the range of depths from 35 to 70 m that possibly correspond to deposits of pleystotsenovy age. It is possible that the thin deposits created during the last Valdai freezing can be sources of these high-frequency anomalies. The second deep range is created by sources of AMF the top edges of which are located in the range of depths of 260–510 m that possibly corresponds to stratigrafichesky range from top Yura to the lower chalk. The third, the deep range of bedding of the top edges of sources of AMF allocated by authors is determined by the most low-frequency part of a range and according to authors reflects the late Devonian stage of activization of magmatism.

Vibroseis Nonlinear Scanning Signal Simulation Analysis

2013 ◽  
Vol 318 ◽  
pp. 191-195
Author(s):  
Gong Ming Zheng ◽  
Yuan Yuan Shen ◽  
Ling Ling Song
Keyword(s):  
High Frequency ◽  
Seismic Waves ◽  
Simulation Analysis ◽  
Frequency Component ◽  
Seismic Exploration ◽  
High Frequency Component ◽  
Frequency Components ◽  
Signal Simulation ◽  
Important Means ◽  
Filtering Effect

Vibrator nonlinear scan is an important means of high frequency seismic exploration. With the propagation of seismic waves, High frequency components continue to be absorbed, due to the filtering effect of the earth. Nonlinear scanning technology can get some degree of compensation to the seismic wave loss in the high frequency part in the propagation, by extending the vibration of the high frequency component time. This article through MATLAB simulation, this paper analyzed the nonlinear scanning signals in scanning signals and logarithmic index scanning signals, and the similarities and differences between the two signals are summarized.

scholarly journals A Novel Infrared and Visible Image Information Fusion Method Based on Phase Congruency and Image Entropy

Entropy ◽  
2019 ◽  
Vol 21 (12) ◽  
pp. 1135 ◽  
Author(s):  
Xinghua Huang ◽  
Guanqiu Qi ◽  
Hongyan Wei ◽  
Yi Chai ◽  
Jaesung Sim
Keyword(s):  
Image Fusion ◽  
High Frequency ◽  
Low Frequency ◽  
Frequency Component ◽  
High Frequency Component ◽  
Source Image ◽  
Phase Congruency ◽  
Visible Image ◽  
Image Information ◽  
Frequency Components

In multi-modality image fusion, source image decomposition, such as multi-scale transform (MST), is a necessary step and also widely used. However, when MST is directly used to decompose source images into high- and low-frequency components, the corresponding decomposed components are not precise enough for the following infrared-visible fusion operations. This paper proposes a non-subsampled contourlet transform (NSCT) based decomposition method for image fusion, by which source images are decomposed to obtain corresponding high- and low-frequency sub-bands. Unlike MST, the obtained high-frequency sub-bands have different decomposition layers, and each layer contains different information. In order to obtain a more informative fused high-frequency component, maximum absolute value and pulse coupled neural network (PCNN) fusion rules are applied to different sub-bands of high-frequency components. Activity measures, such as phase congruency (PC), local measure of sharpness change (LSCM), and local signal strength (LSS), are designed to enhance the detailed features of fused low-frequency components. The fused high- and low-frequency components are integrated to form a fused image. The experiment results show that the fused images obtained by the proposed method achieve good performance in clarity, contrast, and image information entropy.

A Raman study of aqueous DMF and DMA solutions at low temperatures

2004 ◽  
Vol 82 (10) ◽  
pp. 1468-1473 ◽  
Author(s):  
K Tomikawa ◽  
H Kanno ◽  
H Kimoto
Keyword(s):  
Aqueous Solution ◽  
High Frequency ◽  
Low Temperatures ◽  
Low Frequency ◽  
Frequency Component ◽  
Solute Concentration ◽  
Area Ratio ◽  
High Frequency Component ◽  
Frequency Components ◽  
Raman Study

Hydrogen bonding in aqueous N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) solutions was studied by Raman spectroscopy of the OH-stretching spectra of water as functions of solute concentration and temperature (from –50 to 50 °C). The Raman spectra were decomposed successfully into two components (the low- and high-frequency components). The peak area ratio of the low-frequency component to the high-frequency component increases exponentially with decreasing temperature. The frequency of the low-frequency component decreases linearly with lowering temperature down to –50 °C at all solute concentrations (solute mol fraction from 0.3 to 0.7). It is shown that the hydrogen bonds in the clathrate structures around DMA molecules are stronger than those around DMF molecules.Key words: Raman spectrum, DMF, DMA, aqueous solution, low temperature.

Galloping Characteristics of Conductor Accreted with Crescent-Shaped Ice

2012 ◽  
Vol 226-228 ◽  
pp. 158-161 ◽  
Author(s):  
Hui Xue Dang ◽  
Feng Li Yang ◽  
Xin Min Li ◽  
Jing Bo Yang
Keyword(s):  
High Frequency ◽  
Software Package ◽  
Free Stream ◽  
Low Frequency ◽  
Frequency Component ◽  
High Frequency Component ◽  
Span Length ◽  
Test Results ◽  
Frequency Components ◽  
Commercial Software Package

Accounting for the disastrous phenomena of ice-accreted conductor galloping, wind tunnel tests of LGJ630/45 conductor accreted with crescent-shaped ice are conducted. Based on the test results, conductor galloping is simulated by employing the PCL language of ANSYS commercial software package and then the influences of span lengths as well as free-stream speeds on galloping characteristics are studied. The results indicate that, conductor galloping consists several different frequency components. With the increase of span length, galloping energy moves from low-frequency component to its high-frequency counterpart, and finally high-frequency component dominates the galloping phenomenon. And with the movement of energy, galloping traces transforms from ellipse to that similar to a butterfly. With the increase of span length, the maximum cable tension first increases, next decreases sharply, and then increases again.

High Speed and High Sensitivity Slip Sensor for Dexterous Grasping

2012 ◽  
Vol 24 (2) ◽  
pp. 298-310 ◽  
Author(s):  
Seiichi Teshigawara ◽  
◽  
Takahiro Tsutsumi ◽  
Yosuke Suzuki ◽  
Makoto Shimojo ◽  
...  
Keyword(s):  
High Frequency ◽  
High Speed ◽  
High Sensitivity ◽  
Frequency Component ◽  
High Frequency Component ◽  
Robot Hand ◽  
Voltage Signal ◽  
Frequency Components ◽  
Slip Sensor ◽  
Gripping Force

Slip-detecting tactile sensors are essential if robot hands are ever to achieve the gripping motions of human hands. In our previous research, we developed a flexible, thin, and lightweight slip sensor that exploits resistance changes in pressure conductive rubber. However, using this sensor, it was difficult to distinguish between object slip and changes in normal force. Therefore, in this research, we investigate a method of identifying object slip by analyzing the frequency components of the output signal from the sensor. As a result, we find that high-frequency components of several kilohertz or more are included in the complex voltage signal immediately before object slip. Therefore, using this high-frequency component, we develop a simple structure sensor that distinguishes between both contact and a state of immediately before slip with high sensitivity. Moreover, we design a slip sensor for a robot hand and examine the effects of noise by manipulation. Finally, we describe an experiment involving the adjustment of the gripping force of a robot hand.

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