Search for: transmission-lines
Total 127 records
Article 5th IFAC Symposium on Power Plants and Power Systems Control 2003, 15 September 2003 through 19 September 2003 ; Volume 36, Issue 20 , 2003 , Pages 1145-1149 ; 14746670 (ISSN) ; Varahram, M. H ; Kumieh, S. P ; Sharif University of Technology
IFAC Secretariat 2003
Common methods for the calculation of electric fields created by power transmission lines assume straight lines parallel to a flat ground and the influence of the sag due to the line weight is neglected. In this paper the magnetic fields of a catenary 3Phase line that has a change in direction was calculated and discussed. It is believed that this work has not been published before. © 2003 IFAC
Article International Review of Electrical Engineering ; Volume 7, Issue 2 , 2012 , Pages 3926-3934 ; 18276660 (ISSN) ; Vakilian, M ; Ghaffarian Niasar, M ; Sharif University of Technology
Praise Worthy Prize 2012
To locate accurately the occurrence of a partial discharge in a power transformer winding, a wide frequency band model of the winding is required. In this paper a wide frequency band Multi Conductor Transmission Line model (MTL) is employed to simulate the propagation of PD signal in transformer windings. The MTL model is briefly reviewed and the related equations of the model are reformulated to easily simulate occurrence of a PD signal along the winding. Software is developed in Matlab to calculate the windings resonance frequencies and the magnitudes of over-voltages occurring between different disks along the winding. Then propagation of PD signal in a power transformer (900MVA, 525kV),...
Article Amirkabir (Journal of Science and Technology) ; Volume 14, Issue 55 A , 2003 , Pages 610-630 ; 10150951 (ISSN) ; Porkar, S ; Vahidi, B ; Sharif University of Technology
Due to biological effects of magnetic fields of high voltage transmission lines and induceed effects on gas pipe line, telecommunication system and inteference with sensitive electronic equipment, many effort have been done to reduce transmission lines magnetic fields and several ideas have been introduced. In this paper we review three methods: phase split, shielded and compacted line methods. With aid of a developed software programme these methods are then applied to transmission lines and the results are analyzed
Calculation of transient electromagnetic field around a transmission line subjected to lightning strokes, Article 2003 IEEE Power Engineering Society General Meeting, Toronto, Ont., 13 July 2003 through 17 July 2003 ; Volume 1 , 2003 , Pages 258-261 ; 0780379896 (ISBN) ; Porkar, S ; Jahromi, A. N ; Sharif University of Technology
In this paper, a new method for the calculation of electromagnetic fields around a transmission line subjected to a lightning strike is described and discussed. The electric fields and magnetic fields are presented graphically as a function of spatial coordinate, as a function of time and as a function of both. It is believed that this exact solution have not been published before. First, a double exponential lightning surge current is injected into a transmission line. Once The temporal variations of current is known, then electric and magnetic fields can be calculated by using the field expressions for electric dipoles over infinitely conducting ground. As the calculation was done for each...
Multi-conductor transmission line networks in analysis of side-coupled metal-insulator-metal plasmonic structures, Article Optics Communications ; Vol. 313, issue , 2014 , pp. 375-381 ; ISSN: 00304018 ; Bahadori, M ; Rezaei, M ; Khavasi, A ; Hodaei, H ; Mehrany, K ; Sharif University of Technology
An approximate and accurate enough multi-conductor transmission line model is developed for analysis of side-coupled metal-insulator-metal (MIM) waveguides. MIM waveguides have been already modeled by single conductor transmission lines. Here, the side coupling effects that exist between neighboring plasmonic structures are taken into account by finding appropriate values for distributed mutual inductance and mutual capacitance between every two neighboring conductors in the conventional single-conductor transmission line models. In this manner, multi-conductor transmission line models are introduced. Closed-form expressions are given for the transmission and reflection of miscellaneous MIM...
Article Australian Journal of Electrical and Electronics Engineering ; Volume 7, Issue 3 , 2010 , Pages 211-223 ; 1448837X (ISSN) ; Vakilian, M ; Blackburn, T. R ; Sharif University of Technology
The first step in the accepted methods of overhead transmission line insulation coordination is to specify a reliability criterion, and then based on this constraint the most economic insulation design is sought. While the objective of an optimal insulation design method is to find an insulation design that minimises the total cost (the sum of the installation cost, operational cost and cost of failure), each of the cost components can be determined on a per-year basis taking into account the equipment's lifetimes. In this paper, through application of ATP software and realising the total cost of different transmission line designs, a set of alternative insulation designs using various surge...
Article IEEE Transactions on Microwave Theory and Techniques ; Volume 66, Issue 7 , 2018 , Pages 3234-3244 ; 00189480 (ISSN) ; Hashemi, S. M. A ; Farzaneh, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2018
Nonlinear transmission lines (NLTLs) are one of the most prominent solid-state sources of high-power RF pulses. However, there is no integrated mathematical basis, which predicts adequately the generated waveforms on an NLTL and those delivered to the load. This analysis is required for designing and optimizing these transmission lines. Most works in this area are related to experimental studies and results. In this paper, we have developed a theoretical basis, which predicts all the required characteristics of the generated RF pulses on a lossy NLTL. The RF amplitude, the maximum voltage, and the central frequency of the generated pulses at each node of an NLTL are formulated. All the...
Article Journal of Lightwave Technology ; Volume 32, Issue 1 , 14 November 2013 , Pages 91-98 ; Sodagar, M ; Mehrany, K ; Eftekhar, A. A ; Adibi, A ; Rashidian, B ; Sharif University of Technology
We present a new method for modeling and design of photonic crystal nano-beam resonators (PCNBRs) based on cascaded transmission lines. The proposed model provides an accurate estimate of the PCNBRs properties such as resonance wavelength and quality factor (Q) with much smaller computation cost as compared to the brute-force numerical methods. Furthermore, we have developed a straightforward technique for the design of high-Q PCNBRs based on resonance modes with Gaussian electromagnetic field profiles. The results obtained by using the proposed transmission line model are compared against numerical and experimental results and the accuracy of the model is verified. The proposed model...
Analysis and design of optical demultiplexer based on arrayed plasmonic slot cavities: Transmission line model, Article IEEE Photonics Technology Letters ; Volume 25, Issue 8 , 2013 , Pages 784-786 ; 10411135 (ISSN) ; Eshaghian, A ; Hodaei, H ; Rezaei, M ; Mehrany, K ; Sharif University of Technology
A simple yet accurate model for the analysis of coupling between arrayed plasmonic slot cavities and bus/drop metal-dielectric-metal waveguides is presented. The evanescent coupling region is replaced by a transmission line section whose propagation constant and characteristic impedance are given in closed form. The side coupling between the bus waveguide and the slot cavity is modeled together with the direct coupling between the slot cavity and the drop channel. The proposed model is validated by using rigorous numerical method, and is used to design a typical demultiplexer
Article Microelectronics Reliability ; Volume 52, Issue 12 , 2012 , Pages 3026-3034 ; 00262714 (ISSN) ; Faez, R ; Moravvej Farshi, M. K ; Sharif University of Technology
Based on the transmission line model (TLM), we present an exact and general transfer function formula, useful for both single multiwall carbon nanotube (MWCNT) and MWCNT bundle interconnects. Using the standard parameters for 22-nm technology node we perform the Nyquist stability analysis, to investigate the dependence of the degree of relative stability for both single and bundle interconnects on the number of walls in each MWCNT its geometry and also on the bundle geometry. The numerical results, for 1- to 30-μm long interconnects composed of 3- to 7-wall-CNTs, show that by increasing the length or the outer shell diameter, both single and bundle interconnects become more stable. On the...
Article IEEE Electron Device Letters ; Volume 31, Issue 12 , 2010 , Pages 1458-1460 ; 07413106 (ISSN) ; Moravvej Farshi, M. K ; Faez, R ; Sharif University of Technology
We present a Nyquist stability criterion based on transmission line modeling for graphene nanoribbon (GNR) interconnects. This is the first instance that such an analysis has been presented for GNR, so far. In this analysis, the dependence of the degree of relative stability for multilayer GNR (MLGNR) interconnects on the geometry of each ribbon has been acquired. It is shown that, increasing the length and width, MLGNR interconnects become more stable
Analytical approach for analysis of nonuniform lossy/lossless transmission lines and tapered microstrips, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 54, Issue 12 , 2006 , Pages 4122-4129 ; 00189480 (ISSN) ; Mehrany, K ; Rashidian, B ; Sharif University of Technology
In this paper, distribution of voltage along a general nonuniform transmission line is expanded in an appropriate form, and by employing an approach similar to conventional and modified differential transfer matrix methods already proposed for optical structures, analytical expressions are obtained for voltage/current distributions and reflection/transmission coefficients. This method shows great accuracy in different test cases and has been found to be superior to the well-known analytical method of small reflections. Notwithstanding, the overall accuracy of proposed approach is further improved by introducing the technique of multiple divisions. In particular, lossy/lossless tapered...
Article IEEE Transactions on Power Delivery, Piscataway, NJ, United States ; Volume 15, Issue 3 , 2000 , Pages 1027-1033 ; 08858977 (ISSN) ; Hadjsaid, N ; Ranjbar, A. M ; Feuillet, R ; Sharif University of Technology
In this paper, an accurate fault location algorithm for series compensated power transmission lines is presented. Distributed time domain model is used for modeling of the transmission lines. The algorithm makes use of two subroutines for estimation of the fault distance - one for faults behind the series capacitors and another one for faults in front of the series capacitors. Then a special procedure to select the correct solution is utilized. Samples of voltages and currents at both ends of the line are taken synchronously and used to calculate the location of the fault. The proposed algorithm is independent of fault resistance and does not require any knowledge of source impedance. The...
Article Journal of Lightwave Technology ; Vol. 32, issue. 15 , August , 2014 , pp. 2659-2665 ; ISSN: 07338724 ; Eshaghian, A ; Mehrany, K ; Sharif University of Technology
A circuit model based on the transmission line theory is proposed to analyze the recently introduced metal-insulator-metal (MIM) complementary split-ring resonators (CSRRs). It is shown that integer and noninteger modes of CSRRs can be characterized by transmission line models with short- and open-circuited terminals. The proposed circuit model is then extended to incorporate side-coupling effects between the CSRRs and straight MIM waveguides. Thereby, simple closed-form expressions are provided for the coupling quality factor. It is shown that waveguide resonator structures based on CSRRs at specific resonance frequency and bandwidth can be smaller than waveguide resonator structures based...
Tunable Stopband HTS Josephson Junction Left-Handed Transmission Line with Independently Biasable Unit Cells, Article IEEE Transactions on Applied Superconductivity ; Volume 30, Issue 1 , 2020 ; Rejaei, B ; Fardmanesh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2020
A practical coplanar Josephson junction left-handed transmission line based on a step-edge junction technique is proposed in high-temperature superconductor technology and analyzed by electromagnetic simulations. The layout is designed for monolayer Yttrium Barium Copper Oxide thin film fabrication process. The propagation stopbands are tunable by controlling bias currents of Josephson junction arrays acting as parallel inductors for unit cells of the transmission line. Unlike the reported designs, each unit cell of our left-handed transmission line is independently biasable due to dc isolation of the unit cells along the transmission line. Being individually biasable is practically...
Article 2006 IEEE Power India Conference, New Delhi, 10 April 2006 through 12 April 2006 ; Volume 2005 , 2005 , Pages 428-432 ; 0780395255 (ISBN); 9780780395251 (ISBN) ; Fotuhi, M ; Sanaye Pasand, M ; Sharif University of Technology
In this paper a reliability model for power transformer protection is proposed. The model is an extension of a previously proposed Markov model for transmission line protection. Optimum routine test and self checking intervals of the power transformer protection system are determined using the extended Markov model. © 2006 IEEE
Mitigation of ac voltage occurring in pipeline located closed to electric transmission lines with design of joint right of way, Article 5th IFAC Symposium on Power Plants and Power Systems Control 2003, 15 September 2003 through 19 September 2003 ; Volume 36, Issue 20 , 2003 , Pages 1151-1154 ; 14746670 (ISSN) ; Varahram, M. H ; Kumleh, S. P ; Sharif University of Technology
IFAC Secretariat 2003
In joint-use corridors where both pipelines and AC electric transmission lines are present, a portion of the energy contained in the electromagnetic field surrounding the electric transmission lines is captured by each pipeline, resulting in induced AC voltages. In this paper a joint power line/pipeline Right ofWay is designed. Suitable single and double circuit configuration of overhead transmission line or suitable distance of buried pipelines from center electric power lines for mitigation of buried pipeline voltage due to AC Inductive Coupling is introduced and discussed. Copyright © 2003 IFAC
M.Sc. Thesis Sharif University of Technology ; Mehrany, Khashayar ; Fardmanesh, Mehdi
Nonuniform superconducting microstrip transmission lines in microwave regime have been investigated. Nonuniform transmission lines provide the capability of controlling line parameters. Photonic structures with subwavelength features can be homogenized and thus be accurately approximated by homogeneous yet spatially dispersive structures. This idea is here applied to nonuniform superconducting transmission lines with subwavelength nonuniformities, i.e. subcentimeter features in the microwave regime. This modelling is quite useful in geometrical and optical control of quasi-TEM wave propagation and dispersion engineering along microwave superconducting lines. This approach has applications...
Modeling of Sub-wavelength Normal and Superconducting Nonuniform Transmission Lines in the Quasi-static Approximation, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mahdi ; Mehrany, Khashayar
In this thesis, we have investigated nonuniform normal and superconducting microstrip transmission lines in microwave regime. Photonic structures with subwavelength features can be homogenized and thus be accurately approximated by homogeneous structures. This idea is here applied to nonuniform transmission lines with subwavelength nonuniformities, i.e. subcentimeter features in the microwave regime. We present an analytical model based on telegraphers’ equations in order to obtain line propagation characteristics; characteristic impedance, propagation constant, and group velocity. The accuracy of analysis in normal and superconducting lines is evaluated by measurement and electromagnetic...
Design of a Robust Active Controller to Suppress the Undesirable Vibration of Power Transmission Lines by Using the Intermediate Actuators and Optimization of Their Locations, M.Sc. Thesis Sharif University of Technology ; Moradi, Hamed
Power transmission lines, which are responsible for the distribution and transmission of electrical energy from the power plant to the consumer areas, due to their characteristics such as long length and flexibility with low structural damping, face environmental irritations, especially the galloping phenomenon, causing many damages annually. In this study, it has been attempted to reduce the vibrations of power transmission lines by designing a robust active control and by using intermediate actuators in such a way that the failures of these lines can be prevented. For this purpose, linear modeling of the system and designing the controller using the pole replacement method have been done....