Yajuan Jia¹, Lisha Shang¹, Jiangping Nan¹, Guangping Hu², Zhigang Fang^3,4,*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 329-344, 2022, DOI:10.32604/fdmp.2022.017734

Abstract The flow past a fixed single transmission conductor and the related heat transfer characteristics are investigated using computational fluid dynamics and a relevant turbulence model. After validating the method through comparison with relevant results in the literature, this thermofluid-dynamic problem is addressed considering different working conditions. It is shown that the resistance coefficient depends on the Reynolds number. As expected, the Nusselt number is also affected by Reynolds number. In particular, the Nusselt number under constant heat flux is always greater than that under a constant wall temperature. More >

Abdullah Shoukat¹, Muhammad Ali Mughal^1,*, Saifullah Younus Gondal¹, Farhana Umer², Tahir Ejaz³, Ashiq Hussain¹

CMC-Computers, Materials & Continua, Vol.71, No.1, pp. 269-285, 2022, DOI:10.32604/cmc.2022.021575

Abstract Transmission line is a vital part of the power system that connects two major points, the generation, and the distribution. For an efficient design, stable control, and steady operation of the power system, adequate knowledge of the transmission line parameters resistance, inductance, capacitance, and conductance is of great importance. These parameters are essential for transmission network expansion planning in which a new parallel line is needed to be installed due to increased load demand or the overhead line is replaced with an underground cable. This paper presents a method to optimally estimate the parameters using the input-output quantities i.e., voltages,… More >

Abir Jendoubi^1,*, Frédéric Legeron²

CMC-Computers, Materials & Continua, Vol.70, No.1, pp. 1461-1477, 2022, DOI:10.32604/cmc.2022.018832

Abstract As inferred from earthquake engineering literature, considering soil structure interaction (SSI) effects is important in evaluating the response of transmission line towers (TLT) to dynamic loads such as impulse loads. The proposed study investigates the dynamic effects of SSI on TLT behavior. Linear and non-linear models are studied. In the linear model, the soil is represented by complex impedances, dependent of dynamic frequency, determined from numerical simulations. The nonlinear model considers the soil non-linear behavior in its material constitutive law and foundation uplift in a non-linear time history analysis. The simplified structure behavior of a typical lattice transmission tower is… More >

Hamdy A. Ziedan¹, Hegazy Rezk^2,3, Mujahed Al-Dhaifallah^4,*

CMC-Computers, Materials & Continua, Vol.67, No.1, pp. 491-518, 2021, DOI:10.32604/cmc.2021.014493

Abstract A new accurate algorithms based on mathematical modeling of two parallel transmissions lines system (TPTLS) as influenced by the mutual effect to determine the fault location is discussed in this work. The distance relay measures the impedance to the fault location which is the positive-sequence. The principle of summation the positive-, negative-, and zero-sequence voltages which equal zero is used to determine the fault location on the TPTLS. Also, the impedance of the transmission line to the fault location is determined. These algorithms are applied to single-line-to-ground (SLG) and double-line-to-ground (DLG) faults. To detect the fault location along the transmission… More >

Hongchun Shu^1,2, Xiaohan Jiang^1,2,*, Pulin Cao², Na An², Xincui Tian², Bo Yang²

Energy Engineering, Vol.118, No.1, pp. 53-71, 2021, DOI:10.32604/EE.2020.012381

Abstract The system impedance instability, high-order harmonics, and frequency offset are main fault characteristics of wind power system. Moreover, the measurement angle of faulty phase is affected by rotation speed frequency component, which causes traditional directional protections based on angle comparison between voltage and current to operate incorrectly. In this paper, a time-domain protection for connected to wind power plant based on model matching is proposed, which compares the calculated current and the measured current to identify internal faults and external faults. Under external faults, the calculated current and measured current waveform are quite similar because the protected transmission lines is… More >

Qigang Sun¹, Jian Wu¹, Dahai Wang^2,*, Yue Xiang², Haitao Liu¹, Xiaobin Sun³

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 287-302, 2020, DOI:10.32604/cmes.2020.09118

Abstract Downburst event is identified as a major cause to failure of transmission lines in non-coastal regions. In this paper, a novel nonlinear analytical frame for quasi-static buffeting responses of hinged and multi-span insulator-line systems are derived based on the theory of cable structure. The closed-form solutions are presented and applied to predict nonlinear response including displacements and other reactions of the system subjected to a moving downburst wind in a case study. Accuracy and efficiency of the derived analytical frame are validated via comparisons with results from finite element method. More >

Maciej Dutkiewicz^1,*, Marcela R. Machado²

Sound & Vibration, Vol.53, No.4, pp. 161-175, 2019, DOI:10.32604/sv.2019.04803

Abstract In the paper an important issue of vibrations of the transmission line in real conditions was analyzed. Such research was carried out by the authors of this paper taking into account the cross-section of the cable being in use on the transmission line. Analysis was performed for the modern ACSR high voltage transmission line with span of 213.0 m. The purpose of the investigation was to analyze the vibrations of the power transmission line in the natural environment and compare with the results obtained in the numerical simulations. Analysis was performed for natural and wind excited vibrations. The numerical model… More >

Marco Orellana¹, Jordi Selga¹, Paris Vélez¹, Marc Sans¹, Ana Rodríguez², Vicente Boria², Ferran Martín¹

CMC-Computers, Materials & Continua, Vol.52, No.3, pp. 159-174, 2016, DOI:10.3970/cmc.2016.052.157

Abstract This paper is focused on the automated synthesis of wideband bandpass filters operating at microwave frequencies and based on electromagnetic bandgap (EBG) structures. The classical counterpart of such filter consists of a combination of transmission line sections and shunt-connected grounded stubs placed at equidistant positions. By replacing the transmission line sections with capacitively-loaded lines (a kind of EBG-based lines) exhibiting the same phase shift at the lower cutoff frequency and the same characteristic (actually Bloch) impedance, filter size is reduced and the spurious pass bands can be efficiently suppressed. In practice, the loading capacitances are implemented by means of patches,… More >

Shiv Narayan¹, Shamala Joshi B¹, Raveendranath U. Nair¹, R M Jha¹

CMC-Computers, Materials & Continua, Vol.31, No.1, pp. 1-16, 2012, DOI:10.3970/cmc.2012.031.001

Abstract The electromagnetic design and performance analysis of dual/ multi-band metamaterial frequency selective surface (FSS) structures have been carried out for radome applications in microwave and millimeter wave frequency regimes. The proposed metamaterial FSS structure, consisting of cascaded MNG (mu-nega -tive) and DPS (double positive) layers, exhibits dual-band transmission responses at V-band and W-band. Excellent transmission efficiency (more than 95%) has been obtained over the frequency range 45.8-53.1 GHz at first resonance, and from 93.0-97.1 GHz at second resonance. The incorporation of additional DPS layer to the proposed metamaterial-FSS structure facilitates multiband bandpass characteristics at 30 GHz (in Ka-band), 64 GHz… More >

J.R. Jimenez-Octavio¹, O. Lopez-Garcia², E. Pilo¹, A. Carnicero²

CMES-Computer Modeling in Engineering & Sciences, Vol.25, No.2, pp. 81-98, 2008, DOI:10.3970/cmes.2008.025.081

Abstract This paper presents a multidisciplinary design and optimization method of power transmission lines. This optimization method solves both mechanical and electrical problems by a new strongly coupled method that also optimizes the potential designs using a genetic algorithm. A multi-objective function is formulated to simplify a constrained typical optimization problem into an unconstrained one. The scope of this work is the sizing and configuration optimization problem with fixed topology. The method is applied to a railway overhead transmission line. The genetic algorithm is applied to mechanical, electrical and electromechanical optimization problems obtaining good results. Finally, the solution of the electromechanical… More >