scholarly journals Thermal Distortion of Signal Propagation Modes Due to Dynamic Loading in Medium-Voltage Cables

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4436 ◽  
Author(s):  
Peter Wouters ◽  
Armand van Deursen
Keyword(s):  
Signal Propagation ◽  
Medium Voltage ◽  
Time Domain Signal ◽  
Phase Medium ◽  
Order Of Magnitude ◽  
The Time Domain ◽  
Phase Conductors ◽  
Schrödinger Perturbation ◽  
Degenerate Modes ◽  
Underground Power Cables

Temperature variation from dynamic cable loading affects the propagation characteristics of transient signals. The distortion of modal signal components as a function of temperature in a three-phase medium-voltage cable is investigated. The temperature influence arises mainly through the complex insulation permittivity, which has a non-linear relationship with temperature. Near the maximum operating temperature of the cross-linked polyethylene insulation, the propagation velocity increases by 0.56% per degree centigrade but is an order of magnitude less sensitive at ambient temperature. The paper presents modeling results based on cable impedance and admittance matrices obtained from electromagnetic field simulation, taking into account the time-varying temperature distribution in the cable cross-section. The results are verified by applying Rayleigh–Schrödinger perturbation analysis. In the time domain, signal patterns shift when the modal propagation velocities change upon cable loading. Moreover, separation of degenerate modes is observed when the cable phase conductors carry an unbalanced current. The perspectives for exploiting the temperature dependency of signal propagation for pinpointing cable defects and for dynamic rating of underground power cables are discussed.

scholarly journals Ultrawideband Impulse Radar Through-the-Wall Imaging with Compressive Sensing

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Wenji Zhang ◽  
Moeness G. Amin ◽  
Fauzia Ahmad ◽  
Ahmad Hoorfar ◽  
Graeme E. Smith
Keyword(s):  
Compressive Sensing ◽  
Time Domain ◽  
Measurement Data ◽  
Acquisition Time ◽  
Time Domain Signal ◽  
Spatially Extended ◽  
Data Volume ◽  
Order Of Magnitude ◽  
New Perspective ◽  
The Time Domain

Compressive Sensing (CS) provides a new perspective for addressing radar applications requiring large amount of measurements and long data acquisition time; both issues are inherent in through-the-wall radar imaging (TWRI). Most CS techniques applied to TWRI consider stepped-frequency radar platforms. In this paper, the impulse radar two-dimensional (2D) TWRI problem is cast within the framework of CS and solved by the sparse constraint optimization performed on time-domain samples. Instead of the direct sampling of the time domain signal at the Nyquist rate, the Random Modulation Preintegration architecture is employed for the CS projection measurement, which significantly reduces the amount of measurement data for TWRI. Numerical results for point-like and spatially extended targets show that high-quality reliable TWRI based on the CS imaging approach can be achieved with a number of data points with an order of magnitude less than that required by conventional beamforming using the entire data volume.

Partial discharge signal propagation in medium voltage branched cable feeder

2018 ◽  
Vol 34 (6) ◽  
pp. 18-29 ◽  
Author(s):  
M. Shafiq ◽  
K. Kauhaniemi ◽  
G. Robles ◽  
G. A. Hussain ◽  
L. Kumpulainen
Keyword(s):  
Partial Discharge ◽  
Signal Propagation ◽  
Medium Voltage

scholarly journals Is the time domain signal-averaged electrocardiogram helpful in patients with ventricular tachycardia without apparent structural heart disease?

1995 ◽  
Vol 18 (10) ◽  
pp. 568-572 ◽  
Author(s):  
Yelena S. K. Orlov ◽  
Michael A. Brodsky ◽  
Michael V. Orlov ◽  
Byron J. Allen ◽  
Rex J. Winters
Keyword(s):  
Heart Disease ◽  
Ventricular Tachycardia ◽  
Time Domain ◽  
Structural Heart Disease ◽  
Time Domain Signal ◽  
The Time Domain

scholarly journals NMR Resolution Enhancement and Homonuclear Decoupling Using Non-Uniform Weighted Sampling

2020 ◽  
Author(s):  
Chris Waudby ◽  
John Christodoulou
Keyword(s):  
Linear Prediction ◽  
Resolution Enhancement ◽  
Simple Method ◽  
Uniform Sampling ◽  
Homonuclear Decoupling ◽  
Time Domain Signal ◽  
Window Functions ◽  
Uniform Noise ◽  
Increased Sensitivity ◽  
The Time Domain

Non-uniform weighted sampling (NUWS) is a simple method for multi-dimensional NMR spectroscopy in which window functions are applied during acquisition by sampling varying numbers of scans across indirect dimensions. While NUWS was previously shown to provide modest increases in sensitivity, here we describe a complementary application to enhance spectral resolution by increasing the sampling of later points of the time domain signal. Moreover, by combining NUWS with carefully constructed apodization functions signal envelopes can be modulated in an arbitrary manner while retaining a uniform noise level, permitting further signal manipulations such as linear prediction and non-uniform sampling (NUS). We leverage this to develop a combined NUWS-NUS scheme for broadband homonuclear decoupling, with substantially increased sensitivity in comparison to constant time experiments.

Fault Diagnosis of Motor Rotor Based on Fuzzy C-Means Clustering Analysis

2013 ◽  
Vol 273 ◽  
pp. 409-413 ◽  
Author(s):  
Yu Xiang Cao ◽  
Xue Jun Li ◽  
Ling Li Jiang
Keyword(s):  
Time Domain ◽  
Clustering Analysis ◽  
Statistical Features ◽  
Fuzzy C Means ◽  
Time Domain Signal ◽  
Fuzzy C Means Clustering ◽  
Important Means ◽  
Fault Diagnostic ◽  
Characteristic Features ◽  
The Time Domain

For the fuzziness of the fault symptoms in motor rotor, this paper proposes a fault diagnostic method which based on the time-domain statistical features and the fuzzy c-means clustering analysis (FCM). This method is to extract the characteristic features of time-domain signal via time-domain statistics and to import the extracted characteristic vector to classifier. And then the fuzzy c-means realizes the classification by confirming the distance among samples, which is based on the degree of membership between the sample and the clustering center. The fault diagnostic cases of motor rotor show that the method which bases on the time-domain statistical features-FCM can detect the rotor fault effectively and distinguish the different types of fault correctly. Therefore, it can be used as an important means of rotor fault identification.

Variability and Corresponding Amplitude–Velocity Relation of Activity Propagating in One-Dimensional Neural Cultures

2007 ◽  
Vol 97 (5) ◽  
pp. 3597-3606 ◽  
Author(s):  
Shimshon Jacobi ◽  
Elisha Moses
Keyword(s):  
Linear Relation ◽  
Signal Propagation ◽  
Front Velocity ◽  
Multielectrode Arrays ◽  
One Dimensional ◽  
Neuron Activation ◽  
Velocity Relation ◽  
Order Of Magnitude ◽  
Chemical Stimuli

We investigate the propagation of neural activity along one-dimensional rat hippocampal cultures patterned in lines over multielectrode arrays. Activity occurs spontaneously or is evoked by local electrical or chemical stimuli, with different resulting propagation velocities and firing rate amplitudes. A variability of an order of magnitude in velocity and amplitude is observed in spontaneous activity. A linear relation between velocity and amplitude is identified. We define a measure for neuron activation synchrony and find that it correlates with front velocity and is higher for electrically evoked fronts. We present a model that explains the linear relation between amplitude and velocity, which highlights the role of synchrony. The relation to current models for signal propagation in neural media is discussed.

Exact Interpolation of Fourier Transform Spectra

1983 ◽  
Vol 37 (2) ◽  
pp. 153-166 ◽  
Author(s):  
Carlo Giancaspro ◽  
Melvin B. Comisarow
Keyword(s):  
Fourier Transform ◽  
Graphical Form ◽  
Acquisition Time ◽  
Time Domain Signal ◽  
Parabolic Interpolation ◽  
Interpolation Procedure ◽  
True Frequency ◽  
Fourier Transform Spectra ◽  
The Time Domain ◽  
Absorption Mode

A systematic study of interpolation of Fourier transform (FT) spectra is reported. Interpolation errors are examined for both frequency determination and intensity determination for different interpolation procedures for both absorption mode and magnitude mode FT spectra. The errors are presented in both analytical and graphical form as functions of the number of zero-fillings and ( T/τ), the ratio of the acquisition time to the relaxation time of the time domain signal. For interpolation of absorption mode spectra, parabolic interpolation is superior to Lorentzian interpolation if T/τ < 2. For T/τ > 2, Lorentzian interpolation is superior. For small values of T/τ, both parabolic interpolation and Lorentzian interpolation of the absorption line shape give greater errors than no interpolation. For interpolation of the magnitude lineshape, interpolation with the “magnitude-Lorentzian” function gives the exact frequency of the continuous spectrum. This interpolation procedure permits exact determination of the true frequency and true intensity for both absorption mode and magnitude mode FT spectra.

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