scholarly journals Simulation of Partial Discharge Induced EM Waves Using FDTD Method—A Parametric Study

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3364 ◽  
Author(s):  
Alaa Loubani ◽  
Noureddine Harid ◽  
Huw Griffiths ◽  
Braham Barkat
Keyword(s):  
Time Domain ◽  
Parametric Study ◽  
Fdtd Method ◽  
Insulation Material ◽  
Frequency Content ◽  
Lateral Direction ◽  
Close Proximity ◽  
Set Up ◽  
The Time Domain ◽  
Uhf Antenna

This paper reports the results of a parametric study on the characteristics of electromagnetic (EM) waves propagated due to surface- and cavity-type partial discharges (PD) in materials using the finite-difference time domain (FDTD) method. First, the EM waves emitted by such discharges in material samples were measured using a broadband aperture antenna. The measurements showed that the frequency range of the measured signals lay within the ultra-high frequency (UHF) range, suggesting that by carefully choosing the UHF antenna characteristics and its location it might be possible to apply this method to characterize the PD-emitted waves; and hence, to potentially use it to detect and monitor PD defects. In this context, the FDTD simulations were used here to simulate the experimental set-up and examine the propagation characteristics of EM waves emitted by such discharges under uniform and non-uniform test electrode configurations. Using an approximation of the exciting PD current pulses, the electromagnetic field components and the voltage signals captured on a simulated monopole sensor were computed in the time domain at various locations. To explore the limits of the application of the UHF method for detecting these PD types, a parametric study was carried out to clarify how the captured signals are influenced by the PD intensity, the frequency content of the exciting PD pulse, the type of insulation material, the dimensions and the position of the UHF antenna. One of the challenges that needs further investigation is the accurate simulation of the actual PD current pulse produced by such discharges, and hence its frequency content, as there is limited or no measured data available. The results showed that while the amplitude of the captured EM signals increase with the PD intensity, no appreciable signal is detected when the PD pulse width is higher than about 4ns, which may not occur often in unbounded air insulated systems. Equally important is the location and orientation of the UHF sensor—the results showed improved sensitivity when the sensor is vertically polarized and placed in close proximity in the lateral direction with reference to the discharge path.

Research on Interference of Electromagnetic Radiation on Micro-Strip Line

2011 ◽  
Vol 110-116 ◽  
pp. 971-976
Author(s):  
Hong You Wang ◽  
Jin Guang Li
Keyword(s):  
Integrated Circuits ◽  
Time Domain ◽  
Integrated Circuit ◽  
Electromagnetic Compatibility ◽  
Fdtd Method ◽  
Field Calculation ◽  
Strip Line ◽  
The Time Domain ◽  
Radiation Conditions ◽  
Response Feature

Micro-strip line is a kind of transmission line that is the most widely used in microwave integrated circuit. With the development of microwave integrated circuits and the increasing work frequency of the micro-strip line, a higher requirement for its electromagnetic compatibility has been raised. Finite-Difference Time-Domain (FDTD) method has characteristics of good adaptability in the analysis of electromagnetic compatibility issues and superiority in complexity of the structure modeling. For these reasons, this Article uses FDTD method which is widely used in electromagnetic field calculation to analyze the time-domain of micro-strip line, calculates its current and voltage induced in ports and discuss the response feature under different radiation conditions.

scholarly journals Ultra Wideband Coplanar Waveguide Antenna with an Improved Gain using a Frequency Selective Surfaces (FSS)

2019 ◽  
Vol 8 (9S) ◽  
pp. 145-149
Keyword(s):  
Time Domain ◽  
Coplanar Waveguide ◽  
Unit Cell ◽  
Ultra Wideband ◽  
Frequency Range ◽  
Rectangular Slot ◽  
Improved Performance ◽  
Set Up ◽  
The Time Domain ◽  
Uwb Applications

In this article, an ultra-wideband FSS reflector has been proposed to enhance the gain of a CPW antenna for UWB applications. A CPW fed antenna having dimensions of 38mm×38mm×1.605mm and FSS unit cell having dimensions 14mm × 14mm × 1.605 mm are presented in the paper. A rectangular slot and stubs are interleaved at the outer edges of the patch for achieving desired characteristics of an ultra-wideband for the frequency range of 3.39 GHz to 12.9 GHz. Simulation results carried out using the CST microwave 2016 version in the time domain are presented for the proposed antenna. An FSS unit cell designed and simulated using periodic boundary conditions and floquet ports is presented. The combined setup of an array of FSS reflector behind the antenna has been simulated in the time domain. This set up shows an improved performance in terms of antenna’s gain. A maximum and minimum gain of 8.14 dB and 4.98 dB has been observed with the presence of FSS reflector behind the coplanar waveguide antenna. A significant improvement of 2.9 dB has been observed over the entire band of antenna’s operation

scholarly journals Hydrological model performance and parameter estimation in the wavelet-domain

2009 ◽  
Vol 6 (2) ◽  
pp. 2451-2498 ◽  
Author(s):  
B. Schaefli ◽  
E. Zehe
Keyword(s):  
Time Series ◽  
Parameter Estimation ◽  
Time Domain ◽  
Model Performance ◽  
Time Varying ◽  
Wavelet Domain ◽  
Frequency Content ◽  
Time Varying Frequency ◽  
The Time Domain

Abstract. This paper proposes a method for rainfall-runoff model calibration and performance analysis in the wavelet-domain by fitting the estimated wavelet-power spectrum (a representation of the time-varying frequency content of a time series) of a simulated discharge series to the one of the corresponding observed time series. As discussed in this paper, calibrating hydrological models so as to reproduce the time-varying frequency content of the observed signal can lead to different results than parameter estimation in the time-domain. Therefore, wavelet-domain parameter estimation has the potential to give new insights into model performance and to reveal model structural deficiencies. We apply the proposed method to synthetic case studies and a real-world discharge modeling case study and discuss how model diagnosis can benefit from an analysis in the wavelet-domain. The results show that for the real-world case study of precipitation – runoff modeling for a high alpine catchment, the calibrated discharge simulation captures the dynamics of the observed time series better than the results obtained through calibration in the time-domain. In addition, the wavelet-domain performance assessment of this case study highlights which frequencies are not well reproduced by the model, which gives specific indications about how to improve the model structure.

Measurements of Shielding Effectiveness of Textile Materials Containing Metal by the Free-Space Transmission Technique with Data Processing in the Time Domain

2013 ◽  
Vol 20 (2) ◽  
pp. 217-228 ◽  
Author(s):  
Nadezhda Dvurechenskaya ◽  
Pawe R. Bajurko ◽  
Ryszard J. Zieliński ◽  
Yevhen Yashchyshyn
Keyword(s):  
Data Processing ◽  
Time Domain ◽  
Free Space ◽  
Coaxial Line ◽  
Shielding Effectiveness ◽  
Experimental Data Processing ◽  
Textile Materials ◽  
Transmission Technique ◽  
Set Up ◽  
The Time Domain

Abstract The results of shielding effectiveness (SE) measurements of textile materials containing metal by the free-space transmission technique (FSTT) in the 1-26.5 GHz frequency range are presented in the paper. It is shown that experimental data processing using time-domain gating (TDG) makes it possible to effectively remove diffracted and reflected components from the desired signal. The comparison with the results obtained by other techniques, namely modified FSTT with TDG and coaxial line probe technique (ASTM D4935-99) is given. The comparison shows that the proposed technique gives more reasonable results while the measurement set-up is simpler in realization.

scholarly journals Electromagnetic Field Coupling to Overhead Wire Configurations: Antenna Model versus Transmission Line Approach

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Dragan Poljak ◽  
Khalil El Khamlichi Drissi
Keyword(s):  
Electromagnetic Field ◽  
Transmission Line ◽  
Time Domain ◽  
Unit Length ◽  
Fdtd Method ◽  
Domain Analysis ◽  
Wire Antenna ◽  
Field Coupling ◽  
The Wire ◽  
The Time Domain

The paper deals with two different approaches for the analysis of electromagnetic field coupling to finite length overhead wire: the wire antenna theory (AT) and the transmission line (TL) method. The analysis is carried out in the frequency and time domain, respectively. Within the frequency domain analysis the wire antenna formulation deals with the corresponding set of Pocklington integrodifferential equation, while the transmission line model uses the telegrapher's equations. The set of Pocklington equations is solved via the Galerkin-Bubnov scheme of the Indirect Boundary Element Method (GB-IBEM), while the telegrapher’s equations are treated using the chain matrix method and the modal equation to derive per-unit-length parameters. For the case of the time domain analysis AT model uses the space-time Hallen integral equation set, while TL approach deals with the time domain version of the telegrapher’s equations. Hallen equations are handled via time domain version of GB-IBEM, while time domain telegrapher’s equations are solved by using Finite Difference Time Domain (FDTD) method. Many illustrative computational examples for the frequency and time domain response, respectively, for several configurations of overhead wires, obtained via different approaches, are given in this paper.

A Parametric Study on Relative Wave Height of Ships in Short Crested Irregular Sea With Forward Speed

2005 ◽  
Author(s):  
Yoshiyuki Inoue ◽  
N. M. Golam Zakaria ◽  
Ryoji Nakai
Keyword(s):  
Time Domain ◽  
Parametric Study ◽  
Fluid Motion ◽  
Irregular Waves ◽  
Linear Potential ◽  
Forward Speed ◽  
Sea Waves ◽  
Wave Heights ◽  
The Time Domain ◽  
General Cargo

This paper deals with the parametric study of relative wave heights of ships in short crested irregular seas. Here linear potential theory has been used to describe the fluid motion and 3-D sink-source technique with forward speed has been used to determine hydrodynamic forces for surface ship advancing in waves at constant speed. The time domain simulations of relative wave heights of typical container ship, bulk carrier, pure car carrier (PCC) and general cargo ships in short crested irregular waves have been carried out for three different sea states and for the parametric study of these vessels, different sizes of ships have been considered. Empirical roll damping has been taken into account in time domain analyses of motion responses of sea going ships in rough seas and for ensuring longer time simulation of the random sea waves, unequal frequency spacing has been used. Finally, the numerical results of the maximum and the significant values of irregular relative wave heights are discussed by comparing with some requirements by a classification society of shipping for the different sizes of ships which might provide some important information for the designer of ocean going vessel to assess possible deck load or bottom impact force on future regulation of designing ship.

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