scholarly journals Probabilistic Assessment of Lightning Related Risk of Transmission Lines Based on Frequency Dependent Modeling of Tower-Footing Grounding System

2018 ◽  
Vol 7 (1) ◽  
pp. 41-50
Author(s):  
J. Gholinejhad ◽  
R. Shariatinasab ◽  
K. Sheshyekani
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Wide Band ◽  
Band Model ◽  
Method Of Moment ◽  
Electrical Parameters ◽  
Frequency Dependent ◽  
Grounding System ◽  
Wide Band Model ◽  
The Time Domain

This paper presents a probabilistic evaluation, based on Monte-Carlo method, for the estimation of insulation risk of failure of overhead transmission lines (TLs). The proposed method takes into account the wide-band model of tower-footing grounding system. The wide-band model of grounding system in frequency domain is obtained by the method of moment solution to the governing electrical field integral equations. The electrical parameters of soil are considered to be either constant or frequency dependent. The time-domain representation of the grounding system is inferred through pole-zero characterization of its associated frequency response. The case of a typical 400-kV transmission line is modelled in EMTP_RV with the tower-footing grounding system integrated with the transmission line (TL) system. The results of the paper show that the failure risk of transmission lines is affected by the grounding system model. This effect is more pronounced when the soil electrical parameters are assumed to be frequency dependent.

ABCD Matrix: A Unique Tool for Linear Two-Wire Transmission Line Modelling

2003 ◽  
Vol 40 (3) ◽  
pp. 220-229 ◽  
Author(s):  
Pedro L. D. Peres ◽  
Carlos R. de Souza ◽  
Ivanil S. Bonatti
Keyword(s):  
Differential Equations ◽  
Transmission Line ◽  
Frequency Domain ◽  
Transmission Lines ◽  
Time Domain ◽  
Mathematical Concepts ◽  
Frequency Dependent ◽  
Abcd Matrix ◽  
The Time Domain

The aim of this note is to show that all the behaviour of a two-wire transmission line can be directly derived from the application of ABCD matrix mathematical concepts, avoiding the explicit use of differential equations. An important advantage of this approach is that the transmission line modelling arises naturally in the frequency domain. Therefore the consideration of frequency-dependent parameters can be carried out in a simple way compared with the time-domain. Some standard examples of transmission lines are analysed through the use of ABCD matrices and a case study of a balun network is presented.

scholarly journals Influence of the Spectral Model of Radiation on the Calculated Characteristics of Complex Heat Exchange in Flame Furnaces of the Petrochemical Industry

2020 ◽  
Vol 6 (6) ◽  
pp. 42-47
Author(s):  
A. Abdullin
Keyword(s):  
Petrochemical Industry ◽  
Wide Band ◽  
Combustion Products ◽  
Heat Fluxes ◽  
Spectral Model ◽  
Band Model ◽  
Total Heat Transfer ◽  
Complex Heat Exchange ◽  
Tube Furnaces ◽  
Wide Band Model

The influence of the spectral model of radiation on heat fluxes and the temperature of combustion products in the radiant chambers of tube furnaces of the petrochemical industry is analyzed. A wide-band model and a Hottel gray model are considered. It is shown that the spectral model of the combustion medium radiation weakly affects the calculated characteristics of the total heat transfer.

scholarly journals Ultra Wide Band (UWB) 3.4 - 4.8 Ghz Bandpass Filter Menggunakan Saluran Transmisi CRLH Satu Sel

2016 ◽  
Vol 2 (1) ◽  
pp. 18-26
Author(s):  
Andika Atmaja
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Bandpass Filter ◽  
Wide Band ◽  
Ultra Wide Band ◽  
Double Negative ◽  
Transmission Line Model ◽  
Artificial Material ◽  
Left Handed ◽  
Highpass Filter

Penelitian studi tentang Metamaterials (MTMs) dalam beberapa tahun terakhir telah meningkat sangat pesat. Metamaterials yang di sebut juga artificial material atau  Left Handed (LH) material adalah material yang tidak ada dialam dimana strukturnya direkayasa oleh manusia yang memiliki dua atau lebih properties yang khusus, misalkan pada Double Negative (DNG) material yang memiliki μ negative dan  ε negative. Beberapa pendekatan dalam mendesign metamaterial yaitu pendekatan resonant dan pendekatan Transmission line. Model transmision line yang pertama adalah Right Handed Transmission lines (RH TL) yang dimodelkan dalam sebuah unit sel sebagai rangkaian dan shunt kapasitor shunt(CR), yang kedua adalah Left Handed Transmission Line (LH TL) dimodelkan dalam sebuah unit sel sebagai rangkaian kapasitor seri(CL) dan induktansi shunt(LL). gabungan dari dua buah model transmission line ini disebut Composite Right-left Handed Transmission Line(CRLH TL)  dan ini menjadi dasar dalam mendesign metamaterial. CRLH transmission line dimodelkan dalam sebuah unit sel sebagai rangkaian kapasitor seri(CL), induktansi seri(LR) dan induktansi shunt (LL) serta induktansi shunt(LL). CRLH TL memiliki negatif, nol dankonstanta propagasi positif sesuai dengan karakteristik dari permitivitas efektif dan permeabilitas[1]. Hasil pengukuran bandpass filter menggunakan saluran transmisi CRLH satu sel menunjukkan frekuensi cutoff pada -10dB terletak pada frekuensi 3.016 GHz pada highpass filter dan 5.359GHz pada lowpass filternya. Sedangkan frekuensi 3.4 GHz terletak pada -4.8415 dB sedangkan frekuensi 4.8 Ghz terletak pada -4.753 dB. Hasil dari perancangan menunjukkan bahwa saluran transmisi CRLH satu sel dapat memenuhi spesifikasi yang diminta.

Nongray Radiative Gas Analyses Using the S-N Discrete Ordinates Method

1991 ◽  
Vol 113 (4) ◽  
pp. 946-952 ◽  
Author(s):  
T. K. Kim ◽  
J. A. Menart ◽  
H. S. Lee
Keyword(s):  
Radiative Heat ◽  
Narrow Band ◽  
Wide Band ◽  
Heat Fluxes ◽  
Discrete Ordinates ◽  
Band Model ◽  
Spectral Correlation ◽  
Discrete Ordinates Method ◽  
Computational Speed ◽  
Wide Band Model

The S-N discrete ordinates method is applied to analyze radiative heat transfer in nongray gases. Spectral correlation between the terms in the equation of transfer is considered for black or nearly nonreflecting walls. Formulations to apply the S-N method using a narrow-band or the exponential wide-band model are presented. The net radiative wall heat fluxes and the radiative source distributions are obtained for uniform, parabolic, and boundary layer type temperature profiles, as well as for a parabolic concentration profile. The narrow- and wide-band nongray solutions are compared with gray-band approximations using the same band models. The computational speed of the gray-band approximation is obtained at the expense of accuracy in the internal fluxes and radiative source distributions. The wall radiative flux predictions by the gray-band approximation are satisfactory.

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