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Matarrese, Vincent D. "Tapered radio frequency transmission lines." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4329.
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A transformation used to obtain solutions for the beam parameter equation of fiber optics is applied to the second order differential equation for nonuniform transmission lines. Methods are developed for deriving possible transmission line tapers from known solutions of the transformed equation. This study begins with a comprehensive overview of previous work done to obtain closed-form solutions for the transmission line equations. Limitations of the lumped parameter model are also discussed. As part of this thesis, a tapered transmission line is constructed, based on one of the solutions obtained from the fiber optics studies. A discussion of the design and measurement results are given in the final chapter.
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Yang, Zemo 1957. "A study of lossy transmission lines." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/292035.
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Under the assumption of quasi-transverse electric and magnetic (quasi-TEM) mode of propagation, the transmission characteristics of a thin film microstrip line have been studied. Several numerical programs were employed to calculate the frequency dependent electrical parameters of the microstrip line, and to carry out the transient simulation in the thesis. Based on the simulation results, the relations of pulse distortion to the signal frequency content and the length of line have been investigated. Several transmission characteristics, such as attenuation and dispersion have been paid more attention, and their dependences on the frequency dependent electrical parameters have also been studied. Furthermore, a designing rule for the geometry of thin film microstrip lines is drawn, and a general conclusion is made concerning the effect of conductor losses on thin film microstrip line parameter and the things which should be considered in the design.
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Qian, Xin. "Optical waveguide analysis using transmission lines." Thesis, Bournemouth University, 2005. http://eprints.bournemouth.ac.uk/452/.
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Optical fibres have been used as a key medium for telecommunication and networking for more than two decades because in principle they offer sufficient transmission capacity, reaching total rates as high as Tbits/s per fibre. Critical fibre properties such as mode field profiles, single-mode propagation conditions and dispersion characteristics can all be related to the optical fibre refractive index profiles. For this reason, it is of fundamental importance to be able to determine the optical fibre refractive index profiles. In this thesis, a novel Transmission-Line technique has been studied and extended for both the forward and inverse solutions. In the forward solution of the Transmission-Line technique, it is shown that the technique is not only capable of determining exactly the propagation constants in optical fibres with real refractive index profiles, but also evaluating accurately the complex propagation constants in single-mode fibres with arbitrary complex refractive index profiles. To illustrate the effectiveness of this technique, it is applied to the evaluation and manipulation of the gain in a typical 980 nm pumped Erbium-Doped fibre as well as to the calculation of the attenuation of optical fibres when radial loss factors are presented. Moreover, based on the Transmission-Line equivalent circuit model, the exact analytical formulas are derived for a recursive algorithm which allows direct and efficient calculation of dispersion of arbitrary refractive index profile optical fibres. The proposed algorithm computes dispersion directly from the propagation constants without the need for curve fitting and successive subsequent numerical differentiation. The algorithm results in savings for both storage memory and computation time. In the inverse solution using the Transmission-Line technique, the optical fibre refractive index profile synthesis from the given mode electric field distribution is developed and demonstrated. The application of the Transmission-Line principles in the study of optical fibre properties was developed for the first time in the early 80's. However, until now the potential of using Transmission-Line technique for the design of optical fibres based on the given electric field pattern had not been examined. From Maxwell's equations, the Transmission-Line equivalent circuits are derived for a homogeneous symmetric optical fibre. This work demonstrates how to use the Transmission-Line model to reconstruct the exact refractive index profile from the electric field data. The accuracy of the reconstructed optical fibre refractive index profile is examined numerically.
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Liu, Qing. "Antennas using left handed transmission lines." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/595/.
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The research described in this thesis is concerned with the analysis and design of conventional wire antenna types, dipoles and loops, based on the left-handed transmission line approach. The left handed antennas have a unique feature that the wavelength of the induced current becomes shorter with decreasing frequency. The left handed transmission line concept can be extended to construct reduced-size dipole or loop antennas in the VHF frequency band. The use of higher order modes allows orthogonal polarisation to be obtained, which is thought to be a feature unique to these antennas. Efficiency is a key parameter of left handed antennas as the heavy left handed loading increases the resistive loss. A study of the efficiency of small dipole antennas loaded with a left-handed transmission line is specially described, and the comparison with conventional inductive loading dipoles. In a low order mode, the efficiency of L-loading dipole is better with low number of unit cell. If the number of cell increases, CL-loading presents comparable and even better performance. In a high mode the meandered left handed dipole gives the best efficiency due to the phase distribution, presenting orthogonal polarization as well. The optimized dipole loaded with parallel plate capacitors and spiral inductors presents the best performance in impedance and efficiency, even better than the conventional inductive loading. A planar loop antenna using a ladder network of left handed loading is also presented. Various modes can be obtained in the left handed loop antenna. The zero order mode gives rise to omnidirectional patterns in the plane of the loop, with good efficiency. By loading the loop with active components, varactors, a tunable left handed loop antenna with a switchable radiation pattern is implemented. The loop gives an omnidirectional pattern with a null to z axis while working in an n = 0 mode and can switch to a pattern with a null at phi = 45° in the plane of the loop in an n = 2 mode.
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Irfan, Nazish. "Simulation of incident field coupling with nonuniform transmission lines." Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27855.
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This thesis develops a new algorithm to simulate incident field coupling with high-speed interconnects. The interconnects considered in this thesis are represented by nonuniform multi-conductor transmission lines and are described through the Telegraphers Equations. The developed algorithm is based on the concept of model-order reduction via projection onto Hilbert space, where a reduced-order model representing the transmission line is constructed and employed as a stamp for representing the line. The incident field is represented by a set of terminal sources obtained from the projection operator used in constructing the reduced-order model. In addition to being developed to handle nonuniform transmission lines, the proposed algorithm offers an advantage by guaranteeing the passivity of the reduced order model. Several examples are presented to validate the validity and accuracy of the proposed algorithm.
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Thomas, David William Phillip. "Protection of major transmission lines using travelling-waves." Thesis, University of Nottingham, 1990. http://eprints.nottingham.ac.uk/14111/.
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An ultra high speed relay for the protection of long EBY transmission lines is described in this thesis. The need for ultra high speed relays is first discussed. From a brief review of protection based on "impedance" distance algorithms or methods using post fault transients, it is shown that at present, there is no truly ultra high speed relay available for the protection of long EBY transmission lines. The proposed relay operates on the incident fault transient travelling waves received at the relaying point only. After the arrival of the first incident transient at the relaying point all subsequent incident travelling waves are detected using the cross-correlation of the first reflected wave with the incident transient waves. From the amplitudes of the subsequent incident transients, two fault resistance estimates are obtained. These two fault resistance estimates are in agreement only for the subsequent incident wave which is caused by direct reflection from the fault. The fault location can then be determined from the time of arrival of this wave. Additional checks based on the ground mode delay or the line round trip wave amplitude, are incorporated to enhance further the security of the scheme. Good fault discrimination is shown to be possible over a large range of fault resistances for symmetric three phase faults to ground, phase to ground faults and phase to phase faults. Double circuit transmission lines and compensated transmission lines can also be protected. The relay has good noise tolerance and a reasonable bandwidth requirement. A real time implementation of the basic algorithm for an internal phase-a to ground fault shows that an ultra high speed relay response with good accuracy can be achieved using currently available digital hardware.
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Almajali, Ziyad. "Fault diagnosis for transmission lines using chromatic processing." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2019779/.
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Diagnosing the type of fault and its location in a transmission lines is performed by a variety of techniques and mainly relies on monitoring currents and voltages in the transmission line. Accurate fault diagnosis plays an important role in improving the overall system reliability, has a significant effect on the quality of service provided, improves the protection system efficiency, reduces power outage time and limits the risks and the economic losses. Transmission lines extend over wide areas and are exposed to vulnerable situation, to the harsh and uncontrolled environment random events (e.g.~lightning), this can lead to loss of lines due to various faults. This fact has an attraction for researchers to focus on utilising possible methods to improve protection system and supporting fault diagnosis solutions to overcome many of the transient fault conditions. This thesis explores an alternative method of fault diagnosis and location. The approach uses chromatic methodology to extract information from current and voltage waveforms from a simulated transmission line with different fault conditions. These waveforms are processed chromatically. The process involves two steps, filtering which is performed on a cycle by cycle basis of the three symmetrical components for each waveform, and then using the chromatic transformations to represent the outputs in an information space. Various chromatic models are available but the hue, lightness and saturation (HLS) model is employed in this study and the relation between changes in the waveforms and changes in the chromatic parameters forms the foundation for building the proposed diagnosis algorithms. A fault type classifier algorithm for the asymmetrical faults has been proposed for both, double and single line transmission systems. It employs the chromatic H parameter variation with the fault type for the negative sequence component. The processed waveforms are either the voltage or the current at a single terminal of the transmission line. L chromatic parameter values of the zero sequence component are incorporated in the algorithm to add the ground fault distinguishing element and the L parameter values of the rectified negative sequence component were used to support the classification decision even with high fault resistance. Another algorithm for fault location estimation for all types of faults has been used for the double transmission line system. It employs the L chromatic parameter values of the rectified positive sequence component. The processed waveforms are the current collected from both terminals of the transmission line. Finally, the proposed algorithms have been tested by variation of possible conditions of the faults, such as changing the fault location, the fault resistance, the line configurations and parameters, etc. In addition to robustness testing with different fault scenarios. Experimental results taken from a lumped parameter laboratory system have been also used to verify the outputs of the chromatic processing. The performance of the chromatic approach and other reported methods have been compared. The error of the chromatic method compares favourably with others. As such overall performance can be described as being good, this is encouraging and future work through proposing diagnostic tools for other power system components is needed.
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Baumgartner, Claus Ernst 1961. "Simulation methods for multiconductor transmission lines in electronic applications." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/284323.
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Accurate and efficient simulation of lossy, multi-conductor transmission lines that are terminated by nonlinear circuits is necessary to design high-performance electronic circuits and packages. In this work, theoretical and practical considerations of lossy line simulation are presented. Using delay differential equations, the class of systems with "bidirectional delay" is introduced. These systems can be partitioned such that the resulting subsystems are only linked via delayed variables. It is stated in the "decoupling theorem" that the subsystems can be solved independently for a time interval, which is not longer than the shortest time delay. Circuits that contain transmission lines are shown to form systems with bidirectional delay and, consequently, can be decoupled. Using concepts derived from waveform relaxation, the decoupling is exploited to reduce the computational effort required for transmission line simulation. Moreover, an efficient method for the approximation of lossy line characteristics by rational transfer functions is presented. The method employs nonlinear minimization techniques and yields function coefficients suitable for time-domain modeling. Furthermore, the exponential wave propagation function is represented in the time domain, and discrete-time convolution is employed to calculate the transmission line response. Also described is a filtering method which considerably improves the stability of the simulation, while the deviation in the simulation results is smaller than the local truncation error. In addition, implementation of the lossy line simulator "UAFLICS" is outlined, and practical applications demonstrate the significance of coupling and loss effects.
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Tax, David S. (David Samuel). "Mode conversation losses in overmolded millimeter wave transmission lines." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45855.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (p. 106-109).
Millimeter wave transmission lines are integral components for many important applications like nuclear fusion and NMR spectroscopy. In low loss corrugated transmission lines propagating the HE,1 mode with a high waveguide radius to wavelength ratio (a/X), the transmission line loss is predominantly a result of mode conversion in components such as miter bends. The theory for determining losses in miter bends though is only approximate, and is based instead on the problem of the loss across a diameter-length gap between two waveguide sections. Through simulation, we verified that the existing analytic theory of this gap loss is correct; however, our simulations could not verify the assumption that the miter bend loss is half the loss in the gap. We also considered the problem of higher order modes (HOMs) mixed with an HE11 input entering the miter bend. Using a numerical technique, we found that the loss through the miter bend is dependent on both the amplitude of the HOM content as well as its phase relative to the phase of the HE11 mode. While the overall loss averaged across all phases remains the same with increasing HOM content, the power that fails to traverse the gap tends to increase, and it is this power that appears as very high order modes that will cause heating around the miter bend. For the ITER transmission line, the loss based on gap theory is 0.027 dB and, using a coherent technique, we measured a loss of 0.05 + 0.02 dB with a vector network analyzer (VNA).
(cont.) We also set out to measure the mode conversion caused by a miter bend by using a 3-axis scanner system to measure the field patterns within the ITER waveguide. Due to the presence of higher order modes output by the HE I launcher, definitive results on the mode conversion attributed to the miter bend could not be obtained. Using a phase retrieval code, we were able to calculate the mode purity of the launcher output and found it to be 98 + 0.5 %. Future work will concentrate on reducing this HOM content to enable measurements of the miter bend mode conversion.
by David S. Tax.
S.M.
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Jamali, Sadegh. "Accurate fault location for power transmission lines." Thesis, City, University of London, 1990. http://openaccess.city.ac.uk/17425/.
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This thesis describes a new accurate fault location technique for power transmission lines. The technique is based on a distributed parameter line model which inherently accounts for line conductor asymmetry and shunt capacitance. The accuracy of the new technique is not significantly affected by fault resistance, source network configuration or line length. Also, in most cases no fault type identification is required. The new fault location technique uses the current and voltage phasors at power frequency measured at the line ends. These measurements are synchronised from a knowledge of the prefault phasor data. For a single-phase network the basic idea is to equate two equations obtained for the fault point voltage; one from the sending end phasor data and the other from the receiving end phasor data. The resultant equation is solved for the distance to fault. For multiphase systems the idea is 'generalised by using the theory of natural modes which involves the evaluation of eigenvalues and eigenvectors of the lines. In this way a multiphase system is decoupled into a number of single-phase modal circuits; each circuit can be solved for fault location. For perfectly transposed lines the eigenvalues can simply be evaluated from the sequence components and a real eigenvector matrix can be defined for all the lines. For untransposed lines the new algorithm maintains its high accuracy when assuming perfect transposition to simplify the evaluation of eigenvalues and eigenvectors. Also for double-circuit applications a circuit-by-circuit fault location, without any link between the two circuits, is possible. The test results for different fault conditions presented in this thesis show the higher accuracy in fault location achieved by the new,algorithm in comparison with the algorithms used in the best commercially available fault locators.
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Ayyagari, Suhaas Bhargava. "ARTIFICIAL NEURAL NETWORK BASED FAULT LOCATION FOR TRANSMISSION LINES." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_theses/657.
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This thesis focuses on detecting, classifying and locating faults on electric power transmission lines. Fault detection, fault classification and fault location have been achieved by using artificial neural networks. Feedforward networks have been employed along with backpropagation algorithm for each of the three phases in the Fault location process. Analysis on neural networks with varying number of hidden layers and neurons per hidden layer has been provided to validate the choice of the neural networks in each step. Simulation results have been provided to demonstrate that artificial neural network based methods are efficient in locating faults on transmission lines and achieve satisfactory performances.
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Ghimire, Sushma. "Analysis of Fault location methods on transmission lines." ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1800.
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Analysis of different types of fault is an important and complex task in a power system. Accurate fault analysis requires models that determine fault distances in a transmission line. The mathematical models accurately capture behavior of different types of faults and location in a timely manner, and prevents damaging power system from fault energy. The purpose of this thesis is to use two methods for determining fault locations and their distance to the reference end buses connected by the faulted transmission line. The two methods used in this investigation are referred to as impedance-based and traveling wave methods. To analyze both methods, various types of faults were modeled and simulated at various locations on a two-bus transmission system using EMTP program. Application and usefulness of each method is identified and presented in the thesis. It is found that Impedance-based methods are easier and more widely used than traveling-wave methods.
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Schilder, Melanie. "Wideband modelling of capacitive voltage sensors for open-air transmission line applications." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/53222.
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Thesis (PhD)--University of Stellenbosch, 2002.ENGLISH ABSTRACT: This dissertation considers the wideband modelling of capacitive voltage sensors for open-air transmission line applications. Two novel topologies were introduced, namely a differential parallel plate sensor with a floating faraday cage for the interface instrumentation and a coaxial sensor mounted around the earth conductor with a faraday cage connected to the earth conductor. The modelling and analysis procedures included the derivation of equivalent circuit models in order to simulate the calibration factor, the loading effect of the interface instrumentation and the effect of leakage to ground, both in the time- and frequency domain. In order to obtain a flat frequency response from very low frequencies (less than 5 Hz) to very high frequencies (several MHz) it is important that the interface instrumentation have a high input impedance and galvanic isolation be maintained. This was achieved by developing interface instrumentation with a fibre-optic link operated from battery power. The instrumentation represents a fairly unique approach in that the data is digitised before transmission across the serial fibre-optical link, where-as conventional interfaces use analogue optical technology. Despite the added complexity and high power requirements introduced by the digitising process, the improved versatility is expected to yield a superior interface solution. The instrumentation has a bandwidth of approximately 6 MHz, with an optional anti-aliasing filter at 1 MHz. Special consideration should be given to the support structure as any unbalanced leakage to ground will introduce variations in the frequency response towards the low-frequency end. Leakage of a 100 MQ was found to influence the frequency response of the circuit up to frequencies of 1 kHz. Extensive simulation studies were conducted to obtain qualitative and quantitative insight into the differential sensor topology and the associated electric fields. The improvement of a differential plate sensor over the traditional single element plate sensor was demonstrated using twodimensional simulations. Further simulations with a three-dimensional package showed that the two-dimensional simulations are insufficient, because the boundary conditions and end effects have a great influence on the calibration factor of the sensor. Extensive laboratory tests were also undertaken to evaluate the sensor topology as well as the effects of the interface instrumentation and leakage to ground. Excellent correlation were found between the measured and simulated waveforms, both in the time- and frequency domains regarding the calibration factor as well as the added poles or zeros at low frequencies. It can therefore be deduced that a valid circuit model was suggested for these sensor topologies in the frequency range from 10 Hz to 1 MHz. Keywords: Capacitive sensors, Open-air voltage sensors
AFRIKAANSE OPSOMMING: Hierdie verhandeling beskou die wyeband modellering van kapasitiewe spanningsensors vir opelug transmissie lyn toepassings. Twee oorspronklike topologieë is voorgestel, naamlik 'n differensiële parallel plaat sensor met 'n aparte faraday hok vir die koppelvlak instrumentasie en 'n koaksiale sensor wat rondom die aardgeleier monteer word met die faraday hok ook aan die aardgeleier gekoppel. Die modellerings en analise prosedures het ingesluit die afleiding van ekwivalente stroombaanmodelle vir simulasie van die kalibrasiefaktor asook die belasingseffek van die koppelvlak instrumentasie en lekweerstand na grond in beide die tyd- en frekwensie gebiede. Om 'n plat frekwensieweergawe te verkry vanaf baie lae frekwensies (laer as 5 Hz) tot by baie hoë frekwensies Cn paar MHz), is dit belangrik dat die koppelvlak instrumentasie 'n hoë intreeimpedansie het en galvaniese isolasie verseker word. Dit was bereik deur koppelvlak instrumentasie te ontwikkel met 'n optiese vesel koppeling wat met battery krag aangedryf word. Die instrumentasie verskaf 'n redelik unieke aanslag in die opsig dat die data gemonster word voordat dit oor die seriële optiese vesel skakel gestuur word, terwyl konvensionele koppelvlakke analoog optiese tegnologie gebruik. Ten spyte van die toegevoegde kompleksiteit en hoë drywingsvereistes van die versyferingsproses, het die instrumentasie se veelsydigheid toegeneem tot die mate dat dit as 'n beter koppelvlak oplossing beskou word. Die instrumentasie het 'n bandwydte van ongeveer 6 MHz, met 'n opsionele teen-vou filter by 1 MHz. Die ondersteuningstruktuur is van besondere belang aangesien enige ongebalanseerde lekweerstand na grond afwykings in die frekwensieweergawe sal veroorsaak aan die lae frekwensie kant. Lekweerstand van 100 MQ sal die frekwensieweergawe beïvloed tot by ongeveer 1 kHz. Uitgebreide simulasies is gedoen om kwalitatiewe en kwantitatiewe insig in die differensiële sensor topologie en die geassosieerde elektriese velde te verkry. Die verbetering van 'n differensiële parallel plaat sensor in vergelyking met die tradisionele enkel element plaat sensor is demonstreer met twee-dimensionele simulasies. Verdere simulasies met 'n drie-dimensionele pakket het gewys dat die twee- dimensionele simulasies onvoldoende is aangesien grensvoorwaardes en randeffekte 'n groot invloed het op die kalibrasiefaktor van die sensor. Uitgebreide laboratorium toetse is ook gedoen om die sensor topologie sowel as die effekte van die koppelvlak instrumentasie en lekweerstand na grond te evalueer. Uitstekende korrelasie is gevind tussen gemete en voorspelde golfvorms, in beide die tyd- en frekwensie gebied met betrekking tot die kalibrasie faktor sowel as die toegevoegde pole en zeros by lae frekwensies. Die gevolgtrekking is dus dat 'n geldige stroombaanmodel voorgestel is vir die sensor topologieë vir die frekwensie bereik van 10Hz to 1 MHz. Sleutelwoorde: Kapasitiewe sensors, Ope-lug spanningsensors
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Cecchi, Valentina Miu Karen Nan. "A modeling approach for electric power transmission lines in the presence of non-fundamental frequencies/." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2583.
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Zevallos, Alcahuaman Milton Elvis 1974. "Otimização de linhas de transmissão para manobra de abertura monopolar - análise da influência dos parâmetros transversais do sistema de compensação reativa." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260990.
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Orientador: Maria Cristina Dias TavaresTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-25T04:28:30Z (GMT). No. of bitstreams: 1 ZevallosAlcahuaman_MiltonElvis_D.pdf: 2479285 bytes, checksum: 4c1c5f42e8da1a073caee7cb88308479 (MD5) Previous issue date: 2013
Resumo: Uma solução bastante utilizada para reduzir a corrente de arco secundário nas linhas aéreas de transmissão em extra-alta-tensão após a ocorrência de faltas monofásicas não permanentes é a inserção de um reator de neutro no arranjo dos reatores dos bancos de compensação reativa em derivação da linha. Muitas vezes estes reatores de neutro não são otimizados, de modo que reatores com valores típicos são especificados nos projetos de linhas de transmissão aéreas, baseados simplesmente no seu nível de tensão, mas sem considerar as especificidades das linhas, como as suas características físicas ou o seu comprimento. A especificação inadequada do reator de neutro pode resultar em correntes de arco secundário elevadas, o que, em última análise, pode reduzir a taxa de sucesso da manobra de religamento monopolar. Além disto, o custo do sistema de compensação pode ser maior do que o necessário. A tese apresenta uma extensa análise de sensibilidade dos principais parâmetros que influenciam no dimensionamento de um tronco de transmissão longo, especificamente do nível de compensação mais adequado e do valor ótimo do reator de neutro. Destaca-se na pesquisa o desenvolvimento de uma representação dos componentes de um sistema de transmissão através de quadripolos trifásicos com o intuito de obter a resposta sustentada durante o desequilíbrio. Através desta representação foi possível identificar a relação entre o reator de neutro ótimo e os parâmetros transversais da linha de transmissão, assim como a influência direta entre o nível de compensação do sistema com o valor do reator de neutro otimizado. Adicionalmente foram identificados comprimentos limites para linhas não compensadas de diferentes níveis de tensão de modo a ainda apresentar alta probabilidade de sucesso para a manobra monopolar. Simulações de faltas monofásicas foram realizadas utilizando dados provenientes de linhas típicas do sistema elétrico brasileiro
Abstract: A widely used solution to reduce secondary arc current in the overhead transmission lines in EHV after single-phase non permanents faults is the insertion of a neutral reactor in the arrangement forming part of the shunt reactive compensation of the line. Frequently in Brazilian electrical system, neutral reactors are not optimized, so that reactors with typical values are specified in the project of overhead transmission lines based on their voltage level, but without considering the specifics line parameters, as their physical characteristics or their length. The specification of unsuitable neutral reactor can result in high secondary arc currents, which eventually diminishes the success rate of single-phase automatic reclosure (SPAR) maneuver. Moreover, the cost of the compensation system may be larger than necessary. This paper presents an extensive sensitivity analysis of the main parameters that influence the project of a long transmission trunk, specifically the most appropriate level of compensation and the optimal value of the neutral reactor. It is noteworthy the development of a transmission system components representation using three-phase two-ports networks in order to obtain sustained response during unbalance. Through this analysis it was possible to identify the relationship between the shunt reactor and the optimized neutral parameter and the influence of the compensation level with the neutral reactor optimized value. Additionally the maximum lengths of non-compensated lines that would have high probability of success of SPAR maneuver were identified. Simulations of single-phase faults were performed using data from typical lines of the Brazilian electric system
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica
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Mswane, Luke Mdumiseni. "Lightning performance improvement of the Swaziland Electricity Board transmission system (66kV & 132kV lines)." Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/5152.
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Ho, Jeffrey. "Analysis of transmission lines embedded in power distribution networks containing electromagnetic bandgap structures." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98967.
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Electromagnetic bandgap (EBG) structures are known for their frequency selective characteristics. They are easily implemented in printed circuit board (PCB) technology and can be designed to induce wide stopbands. Due to this feature, the EBG structures are utilized in power distribution networks (PDNs) in order to provide global power/ground noise suppression. Signal integrity in transmission lines routed within such a modified PDN is investigated in this thesis. For this purpose, a lumped element circuit model is introduced that is portable to commercial circuit simulators. This model, which includes losses and frequency dependent parameters, is validated with full-wave simulations, time domain pulse response and scattering parameter measurements. As well, data transmission in such a line is inspected by simulation and measurement of the eye-diagrams. Subsequently, a system simulation is performed to show the integration of the model in a typical electronic circuit containing logic gates and drivers and to demonstrate a sample application of the noise suppression method. Alternative PDN geometries employing EBG structures are also introduced to decrease the cost and complexity of fabrication and to increase the frequency range of the stopband induced by the EBG.
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D'Asaro, Matthew E. (Matthew Eric). "Flexible and stretchable tactile sensing skins using microwave transmission lines and piezoresistive rubber." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111855.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 225-232).
In the related fields of prosthetics and robotics there is a need for an inexpensive, durable, wide-area, flexible stretchable skin-like material that can sense pressure and shear. While there exists a variety of tactile skins with impressive sensitivity, resolution, and integration, they are complex, expensive to fabricate, and delicate. This thesis explores two distinct technologies for creating a sensing skin based on molded PDMS silicone rubber. The first, which serves as a baseline technology for this thesis, consists of arrays of sensors made of insulating PDMS, conducting metal doped PDMS, and piezoresistive carbon black doped PDMS. Flexible and stretchable sensors capable of sensing pressure, shear, and finger angle were demonstrated. The finger angle sensor showed a sensitivity of greater than 2.3 k[omega] per degree with a 230 k[omega] resting resistance and the pressure sensor showed a sensitivity of 253 [omega] per kPa with a resting resistance of 97 k[omega]. However, the sensors showed hysteresis, poor repeatability, and had a slow response time due to the CB/PDMS material having a 200 s time constant. They also required a minimum of 2[square root]N wires at the edges of a rectangular array of N sensors. The second technology, which is novel for tactile skins, is a distributed sensor based on buried microwave transmission lines. Applied pressure deforms the silicone rubber dielectric, creating an impedance discontinuity that is used to determine the location and degree of deformation. Using an algorithm derived in this thesis, the sensor deformation can be reconstructed from S-parameter measurements across frequency. The advantages of this sensor include that it requires only one electrical connection (and ground), it is rugged, simple, and inexpensive to make, the response time is ultimately limited only by the mechanics of the sensor materials, and the sensor is easy to model. These sensors showed pressure sensitivity of at least 10 kPa, depression sensitivity of less than 20 [mu]m, and 1-D spacial sampling of 7.3 mm. They are 1.6 mm thick, 13 mm wide, and 200 mm long with the thickness and usable length of the sensor limited by the conductivity of stretchable conductors. In addition, a proof-of-concept shear sensor based on two parallel transmission lines was demonstrated.
by Matthew E. D'Asaro.
Ph. D.
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Chen, Shelley L. "Programs for calculating high temperature ampacity and sag for overhead electrical conductors." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/17933.
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Hu, Xin. "Some studies on metamaterial transmission lines and their applications." Doctoral thesis, Stockholm : Skolan för elektro- och systemteknik, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10126.
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Chaiwan, Pramote. "NEW ACCURATE FAULT LOCATION ALGORITHM FOR PARALLEL TRANSMISSION LINES." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/813.
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Electric power systems have been in existence for over a century. Electric power transmission line systems play an important role in carrying electrical power to customers everywhere. The number of transmission lines in power systems is increasing as global demand for power has increased. Parallel transmission lines are widely used in the modern transmission system for higher reliability. The parallel lines method has economic and environmental advantages over single circuit. A fault that occurs on a power transmission line will cause long outage time if the fault location is not located as quickly as possible. The faster the fault location is found, the sooner the system can be restored and outage time can be reduced.
The main focus of this research is to develop a new accurate fault location algorithm for parallel transmission lines to identify the fault location for long double-circuit transmission lines, taking into consideration mutual coupling impedance, mutual coupling admittance, and shunt capacitance of the line.
In this research, the equivalent PI circuit based on a distributed parameter line model for positive, negative, and zero sequence networks have been constructed for system analysis during the fault. The new method uses only the voltage and current from one end of parallel lines to calculate the fault distance. This research approaches the problem by derivation all equations from positive sequence, negative sequence, and zero sequence network by using KVL and KCL. Then, the fault location is obtained by solving these equations. EMTP has been utilized to generate fault cases under various fault conditions with different fault locations, fault types and fault resistances. Then the algorithm is evaluated using the simulated data. The results have shown that the developed algorithm can achieve highly accurate estimates and is promising for practical applications.
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Pasik, Michael Francis 1965. "A finite-element analysis of the propagation characteristics of shielded lossy planar transmission lines." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277834.
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A finite-element formulation for the analysis of shielded lossy planar transmission lines is presented. The formulation determines the propagation characteristics of a planar transmission line and avoids spurious non-physical modes with non-zero divergence by requiring the field to be divergenceless. Singularities in the field at perfectly conducting corners are accounted for by using singular basis functions. In addition, a set of entire-domain basis functions are developed to reduce the number of unknowns. A quasi-TEM formulation is also presented to provide a comparison with the full-wave analysis. Numerical results are provided to characterize the propagation characteristics of a microstrip transmission line. In particular, their dependence on the thickness of the microstrip and losses in the substrate is examined. In addition, the propagation characteristics of symmetric coupled microstrip transmission lines of finite thickness and the use of artificial magnetic side walls with stripline geometries are analyzed.
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Castilho, Renato Maioli. "Otimização do uso da linha de transmissão através do monitoramento em tempo real." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261482.
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Orientador: José Pissolato FilhoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Este trabalho apresenta um método de análise do carregamento de linhas de transmissão aérea em tempo real o qual relaciona o respectivo carregamento da linha de transmissão com fatores externos que, direta ou indiretamente, exercem influência sobre os limites de operação da linha. Através da implementação de um sistema de monitoramento em uma linha de 230 kV da Eletronorte, informações atmosféricas e da própria linha foram coletadas e transmitidas via cabo OPGW para um centro de controle onde, a partir de um software, obteve-se a ampacidade da linha em tempo real. Fazendo uso do banco de dados gerado com as informações coletadas pelo sistema de monitoramento e utilizando técnicas de redes neurais artificiais, foi desenvolvido um módulo preditor da temperatura superficial do cabo, possibilitando estimar a ampacidade da linha no curto prazo. A pesquisa se deu em três fases, na primeira foi feito o desenvolvimento dos equipamentos que compõem o sistema de monitoramento, na segunda fase foi feita a implementação do sistema na linha de 230 kV e na terceira fase foi dado o tratamento matemático às informações coletadas. A abordagem realizada dos dados obtidos pelo sistema de monitoramento proposto gerou resultados interessantes no que tange a busca pelo melhor aproveitamento da linha e mostrou ser um sistema bastante útil para a operação no despacho de carga. O sistema de monitoramento analisado neste trabalho de pesquisa, foi desenvolvido pelo Centro de Pesquisa e Desenvolvimento em Telecomunicações - CPqD em parceria com a Universidade Federal do Pará - UFPA e faz parte do programa de pesquisa e desenvolvimento das Centrais Elétricas do Norte do Brasil S.A. - Eletronorte.
Abstract: This paper presents a method of transmission line load analysis in real time, which relates of the transmission line loading with external factors that directly or indirectly exert influence over the operating range of the line. By setting up a monitoring system in a line of 230 kV, weather and line parameters information were collected and transmitted via OPGW cable to a control center where, using dedicated software, we obtained the ampacity of the line in real time. Making use of the database generated with information collected by the monitoring system and using techniques of artificial neural networks, we developed a predictor module surface temperature of the cable, allowing use to estimate the ampacity of the line in the short term. The research was divided in three phases, at first was developed the equipment that make up the monitoring system in the second round was implemented the monitoring system at 230 kV line and in the third stage was given the mathematical treatment of collected information. The data obtained by the proposed monitoring system, has generated interesting results allowing an optimized use of the line the system proved to be very useful for the line loading operation. The monitoring system of loading examined in this research work was developed by the Center for Research and Development in Telecommunications - CPqD in partnership with the Federal University of Pará - UFPA and is part of Centrais Elétricas do Norte do Brasil S.A - Eletronorte research and development program.
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica
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Chen, Jin. "Signal integrity analysis of transmission lines backed by electromagnetic bandgap structures in high speed systems." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86918.
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Signal integrity in transmission lines routed above an Electromagnetic Bandgap (EBG) structure is investigated in this thesis. The EBG structure can be designed to induce a wide omni-directional stopband and when it is employed in a conventional parallel plate power distribution network (PDN), efficient suppression of power/ground or simultaneous switching noise is provided. However, the signal lines that are routed above the EBG structure see an interrupted return current path. To investigate this loading effect, a number of signal routing scenarios in a PDN with an embedded mushroom-type EBG structure are investigated through full-wave simulations. Also one of the sample prototypes was fabricated and characterized in frequency and time domain measurements by S-parameters and the output eye diagrams. Furthermore, an equivalent lumped-element circuit is developed to represent the EBG return path. This model is further developed to be applicable to the studied routing scenarios and can be easily incorporated in commercial circuit simulators. The proposed models enable rapid signal integrity analysis as well as global system simulations. Verified by both simulation and measurement results, the signal integrity characteristics of the signal lines backed by an EBG structure are degraded. In order to improve the quality of signal transmission, a modified configuration is introduced. This solution, which utilizes a solid conductor island in the EBG reference plane, offers an optimal insertion loss profile while maintaining noise suppression characteristics of the embedded EBG structure in the PDN.L'intégrité des signaux sur les lignes de transmission au dessus de structures électromagnétiques de bande interdite (EBI) est investiguée dans ce mémoire. Les structures EBI peuvent être conçues afin d'induire une bande atténuée omnidirectionnelle large et quand employées dans un réseau de distribution de puissance (RDP) conventionnel de lames à faces parallèles, une suppression efficace du bruit associé à l'ouverture et fermeture électronique d'un circuit de puissance est réalisée. Cependant, les lignes de signaux au dessus d'une structure EBI sont sujettes à un chemin de retour de courant interrompu. Pour investiguer cet effet de chargement, quelques scénarios de cheminement de signaux dans un RDP avec une structure EBI de type champignon embarqué sont étudiés par des simulations d'ondes-complète. De plus, un des prototypes a été fabriqué et caractérisé dans le domaine fréquentiel et temporel en utilisant les paramètres de dispersion et des diagrammes en oeil. Également, un modèle de circuit à constantes localisées représentant le chemin de retour du EBI a été développé. Ce modèle a également été poussé afin d'être utilisable dans les scénarios de cheminement de lignes et peut être facilement incorporé dans des simulateurs de circuits commerciales. Les modèles proposés permettent une analyse rapide de l'intégrité des signaux ainsi que des simulations globales de systèmes. Vérifié par des simulations et des mesures expérimentales, les caractéristiques de l'intégrité des signaux des lignes supportées par une structure EBI sont dégradées. Afin d'améliorer la qualité des signaux de transmission, une configuration modifiée est introduite. Cette solution, utilisant une île de conducteur solide dans le plan de référence EBI, offre un profile d'affaiblissement d'insertion optimal tout en maintenant les caractéristiques de suppression du bruit des structures EBI dans un RDP.
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McFarland, Robert Bynum 1964. "Calculation of transmission line parameters for multiconductor lines in a multi-dielectric medium." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278111.
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A method for computing the per-unit-length capacitance matrix and the inductance matrix for multiconductor transmission lines in a multi-dielectric medium is presented. The multi-dielectric medium consists of both planar and non-planar dielectric regions. The formulation is based on an integral equation method for the free charge distribution on conductor surfaces and the polarization charge distribution on the non-planar dielectric interfaces. The kernel of the integral equation is a space domain Green's function for a layered medium. The numerical solution is obtained by the method of moments.
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Kleinhans, Kevin. "Investigation into possible mechanisms of light pollution flashover of 275kv transmission lines as a cause of unknown outages." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1071.
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Huelsewede, Ralf. "Erzeugung ultrakurzer elektrischer Impulse auf nichtlinearen Leitungsstrukturen - Generation of short electrical pulses on nonlinear transmission lines." Gerhard-Mercator-Universitaet Duisburg, 2001. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-09172001-120734/.
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In this work the generation of shock-waves and short electrical pulses on nonlinear transmission lines (NLTL) showing transients down to 3.6 ps and amplitudes of 1V - are presented. Special emphasis is layed upon the development of monolithic integration of planar schottky-diodes and coplanar waveguide structures based on InP-semiconductor material. The methods of simulating nonliear propagation effects on NLTL, designing and technology of NLTL and at last the experimental investigations in order to measure the generatred transients both in the time domain and frequency domain are shown in detail.
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Kowalski, Elizabeth J. (Elizabeth Joan). "Miter bend loss and higher order mode content measurements in overmoded millimeter-wave transmission lines." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62444.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 119-121).
High power applications require an accurate calculation of the losses on overmoded corrugated cylindrical transmission lines. Previous assessments of power loss on these lines have not considered beam polarization or higher order mode effects. This thesis will develop a theory of transmission that includes the effect of linearly polarized higher order modes on power loss in overmoded corrugated transmission line systems. This thesis derives the linearly polarized basis set of modes for corrugated cylindrical waveguides. These modes are used to quantify the loss in overmoded transmission line components, such as a gap in waveguide or a 900 miter bend. The dependence of the loss in the fundamental mode on the phase of higher order modes (HOMs) was investigated. In addition, the propagation of a multi-mode beam after the waveguide was quantified, and it was shown that if two modes with azimuthal (m) indices that differ by one propagate in the waveguide, the resultant centroid and the tilt angle of radiation at the guide end are related through a constant of the motion. These theoretical calculations are useful for high-power applications, such as the electron cyclotron heating in plasma fusion reactors. In addition, this thesis develops a low-power S-Parameter Response (SPR) technique to accurately measure the loss in ultra-low loss overmoded waveguide components. This technique is used to measure the loss of components manufactured to ITER (an experimental fusion reactor) specifications, operated at 170 GHz with a diameter of 63.5 mm and quarter-wavelength corrugations. The loss in a miter bend was found to be 0.022+0.08 dB. This measurement is in good agreement with theory, which predicts 0.027 dB loss per miter bend, and past measurements [18]. The SPR was used to measure the loss in a gap of waveguide and the results were in good agreement with the well-established theoretical loss due to gap, which demonstrates the accuracy of the SPR technique. For both of these measurements, a baseline analysis determined the effects of a small percentage (1-2%) of higher order modes in the system.
by Elizabeth J. Kowalski.
S.M.
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Jeong, Jaehoon. "Analytical time domain electromagnetic field propagators and closed-form solutions for transmission lines." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1105.
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Groch, Matthew. "HV Transmission line and tower inspection safe-fly zone modelling and metrology." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85795.
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Thesis (MEng)-- Stellenbosch University, 2013.ENGLISH ABSTRACT: The deployment of Unmanned Aerial Vehicles (UAV) for power line inspection requires the definition of safe-fly zones. Transient Over-Voltages (TOVs) on the Overhead Transmission Lines (OHTLs) put the UAV at risk if it encroaches on these zones. In order to determine the safe-fly zones of a UAV in the vicinity of OHTLs, realistic full-scale experimental tests are done. Non-linearity in breakdown effects renders small-scale testing and computational work inaccurate. Experimental work is used to describe the close-up approach distances for worst-case scenarios. Testing cannot provide a full solution due to the limitation of the equipment available. Further tests must therefore be done at a specialised facility. Experiments are run in two phases, namely non-linear and linear tests in the High Voltage (HV) laboratory. The non-linear tests are done to derive Minimum Approach Distances (MAD). The linear experiments are used to calibrate FEKO, the simulation tool, to the measurement environment. Once correlation between the linear test data and the simulated data is found, confidence is derived in both the simulation model and the test setup. The simulations can then be used to determine a geometric factor as an input into F. Rizk’s prediction equations. The Rizk equations are used to describe the safe-fly zones alongside OHTLs as an addition to the non-linear experimental work. Along with the standard’s suggestions, the Rizk predictions are formulated in such a way that line-specific solutions can be determined. The suggested clearance values are provided in terms of per unit values, which can be selected in accordance with historical line data. Power line sparking is investigated to better understand the line radiation phenomenon. This understanding could assist in the line inspection process, as well as in the layout of power lines near radio quiet areas. Knowledge of OHTL radiation patterns can aid in the location of corona and sparking sources in the inspection process. Aerial sparking measurements are taken using a UAV carrying a spectrum analyser. Measured sparking levels are used to verify a Computational Electromagnetic (CEM) model. The CEM model can then be used to further investigate OHTL radiation characteristics.
AFRIKAANSE OPSOMMING: Die aanwending van Onbemande Vliegtuie (UAVs) vir kraglyn inspeksies, vereis die definiëring van veilige vlieg sones. Oorspannings (TOVs) op oorhoofse kraglyne (OHTLs) kan hierdie vliegtuie in gevaar stel as hulle die grense van hierdie sones oorskry. Om die veilige vlieg sones van 'n UAV in die omgewing van OHTLs te bepaal, is realistiese volskaalse toetse gedoen. Die nie-lineariteit in afbreek effekte lewer onakkurate kleinskaal toetse en rekenaar werk. Eksperimentele werk word gebruik om die benaderde afstande vir die ergste geval te beskryf. Hierdie werk kan nie 'n volledige oplossing gee nie as gevolg van ‘n beperking op huidige toerusting. Dit beteken dat verdere toetse, by ‘n meer gespesialiseerde fasiliteit, gedoen moet word. Eksperimente is uitgevoer in twee fases: nie-lineêre en lineêre toetse in die Hoogspannings (HV) laboratorium. Die nie-lineêre toetse word gedoen om die kleinste-benaderde-afstand (MAD) af te lei en die lineêre eksperimente word gebruik om FEKO (‘n numeriese elektromagnetika simulasie program) met die metings omgewing te kalibreer. Sodra daar ‘n korrelasie tussen die lineêre data en die gesimuleerde data is, kan daar aangeneem word dat die simulasie model en die toets-opstelling betroubaar is. Die simulasies kan dan gebruik word om 'n meetkundige faktor te bepaal as 'n bydrae tot F. Rizk se voorspellings vergelykings. Die Rizk vergelykings word gebruik om die veilige vlieg sones langs die OHTLs te beskryf. Dit kan dus gebruik word as ‘n toevoeging tot die nie-lineêre eksperimentele werk. Saam met die normale meet standaard voorstellings, is die Rizk voorspellings geformuleer sodat dit die lyn spesifieke oplossings kan bepaal. Die voorgestelde verklarings waardes word in per eenheid waardes beskryf, wat dan gekies kan word met ooreenstemmende historiese lyn data. Kraglyn-vonke word ondersoek om die lyn-bestraling verskynsel beter te verstaan. Hierdie begrip kan in die lyn inspeksie proses en in die uitleg van kraglyne naby radiostilte-areas help. Kennis van OHTL bestralings patrone kan help met die identifisering van corona en vonk-bronne tydens die inspeksie proses. 'n UAV met 'n aangehegte spektrum analiseerder is gebruik om die lug-vonkende metings te neem. Vonk vlakke wat gemeet is word dan gebruik om 'n Numeriese Elektromagnetiese (CEM) model te bevestig. Die CEM model kan dan gebruik word om OHTL bestralings eienskappe verder te ondersoek.
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Venkatesh, Vidya. "Fault Classification and Location Identification on Electrical Transmission Network Based on Machine Learning Methods." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5582.
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Power transmission network is the most important link in the country’s energy system as they carry large amounts of power at high voltages from generators to substations. Modern power system is a complex network and requires high-speed, precise, and reliable protective system. Faults in power system are unavoidable and overhead transmission line faults are generally higher compare to other major components. They not only affect the reliability of the system but also cause widespread impact on the end users. Additionally, the complexity of protecting transmission line configurations increases with as the configurations get more complex. Therefore, prediction of faults (type and location) with high accuracy increases the operational stability and reliability of the power system and helps to avoid huge power failure. Furthermore, proper operation of the protective relays requires the correct determination of the fault type as quickly as possible (e.g., reclosing relays).
With advent of smart grid, digital technology is implemented allowing deployment of sensors along the transmission lines which can collect live fault data as they contain useful information which can be used for analyzing disturbances that occur in transmission lines. In this thesis, application of machine learning algorithms for fault classification and location identification on the transmission line has been explored. They have ability to “learn” from the data without explicitly programmed and can independently adapt when exposed to new data. The work presented makes following contributions:
1) Two different architectures are proposed which adapts to any N-terminal in the transmission line.
2) The models proposed do not require large dataset or high sampling frequency. Additionally, they can be trained quickly and generalize well to the problem.
3) The first architecture is based off decision trees for its simplicity, easy visualization which have not been used earlier. Fault location method uses traveling wave-based approach for location of faults. The method is tested with performance better than expected accuracy and fault location error is less than ±1%.
4) The second architecture uses single support vector machine to classify ten types of shunt faults and Regression model for fault location which eliminates manual work. The architecture was tested on real data and has proven to be better than first architecture. The regression model has fault location error less than ±1% for both three and two terminals.
5) Both the architectures are tested on real fault data which gives a substantial evidence of its application.
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Duro, Magda Aparecida Salgueiro 1968. "Falhas em linhas de transmissão elétrica na região sudeste do Brasil e efeitos do ambiente geofísico." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260919.
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Orientadores: José Pissolato Filho, Pierre KaufmannTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: A atual dependência da sociedade aos diversos sistemas tecnológicos em funcionamento na Terra traz uma constante preocupação pela sua vulnerabilidade a fatores menos conhecidos. As possíveis falhas no fornecimento de energia elétrica podem ocasionar transtornos de grande impacto às comunidades podendo acarretar perdas financeiras expressivas. Diversos fatores podem ocasionar falhas nas linhas de transmissão, entre eles, os fatores climáticos. Nesse contexto, são pouco conhecidas as influências qualitativas de distintos fatores, destacando-se os efeitos do denominado clima espacial. Há indicações que o clima espacial influencia a alta atmosfera terrestre, com repercussão no clima bem como em sistemas de engenharia em operação na Terra. As redes de transmissão de alta tensão representam um grande circuito elétrico pouco acima do solo sujeito a uma série de sobrecargas temporárias de vários tipos, algumas das quais podem levar a falhas. Algumas destas falhas podem estar relacionadas ao ambiente geofísico. Neste trabalho foi analisada uma base de dados sem precedentes de falhas em linhas de transmissão por um longo período (nove anos) numa grande malha localizada no Estado de São Paulo (sudeste do Brasil). O período estudado (1998-2006) compreende uma significativa fração do ciclo de atividade solar 23. A concessionária responsável (ISA.CTEEP) pela operação das linhas estudadas classifica as falhas em noventa e cinco tipos distintos de causas possíveis, sendo que a maior parte está relacionada às descargas atmosféricas. Este estudo está relacionado aos desligamentos devido às descargas atmosféricas, em duas redes de alta voltagem da companhia, de 138 kV e de 440 kV. No período estudado, estes desligamentos correspondem a 1.957 (42,80%) num total de 4.572 para a linha de 138 kV e de 170 (22,28%) sobre 763 para a linha de 440 kV. Equivale a menos de um a cada dez mil do número total de descargas atmosféricas ocorridas na mesma área, o que demonstra alta resiliência das redes de potência em relação aos raios. Durante a época das chuvas, há uma maior concentração de desligamentos. Para todo o período estudado houve redução de 67% e 77% no número de desligamentos devido às descargas atmosféricas, para as linhas de 138 kV e 440 kV, respectivamente, havendo uma boa correspondência com a redução do número de manchas solares. Nenhuma correlação foi encontrada em relação às atividades geomagnéticas caracterizadas pelo índice planetário (Kp) e pelas grandes tempestades (Dst) tanto em longos quanto em curtos prazos. Uma explicação sugerida associa a diminuição da atividade solar ao aumento da condutividade na atmosfera causada pelo maior fluxo de raios cósmicos. Consequentemente poderá ocorrer uma redução do limiar de voltagem necessário para produzir descargas atmosféricas para provocar desligamentos nas redes de alta voltagem. O circuito elétrico global descrito pelo acoplamento ionosfera-terra (a eletrosfera) exerce um papel importante para explicar a redução dos desligamentos. Com o aumento da condutividade atmosférica as descargas são menos potentes, resultando em menor número de desligamentos com o decréscimo do ciclo solar
Abstract: The current society dependence on the operating technological systems on the Earth brings a permanent concern for their vulnerability to not well known factors. Possible failures in electricity supply can cause inconveniences with large impact to the communities, which may cause significant financial losses. Different factors can cause failures in the transmission networks, including, climate factors. In this context, the influences of various qualitative factors, especially the effects of space weather are not well known. There are indications that space weather affects the upper atmosphere, with repercussions on the climate as well as in engineering systems in operation on Earth. High-voltage transmission networks represent large electrical circuits just above the ground which are subjected to a number of transient overcharges of various kinds, some of which may lead to failures. Some failures might be related to anomalies of the geophysical environment. In the present study we analyze a database consisting in a one unprecedented long series of transmission grid failures (nine years) on high-voltage networks located in São Paulo state (southeastern Brazil). The studied period (1998-2006) includes an important fraction of the solar activity cycle 23. The company responsible by the power grid operator (ISA.CTEEP) classifies causes in ninety-five distinct failure classes to explain the transmission grid shut downs. Most of the failures were attributed to atmospheric discharges. We have studied the failures attributed to atmospheric discharge, in the two power grids of the company, 138 kV and 440 kV. The failures attributed to atmospheric discharge correspond to 1.957 (42.80%) for a total 4.572 at 138 kV and to 170 (22.8%) out of 763 at 440 kV. They correspond to less than one ten thousandth of the actual number of atmospheric discharges recorded in the same area, demonstrating the grid's high resilience to breakdowns due to lightning. A clear concentration of failures in the region's thunderstorm season has been found. A significant 67% and 77% reduction in the number of failure rates has been found for the 138 and 440 kV grids, respectively, for the period studied, in good correspondence with the decay in the sunspot numbers. No obvious correlation was found between power failures and geomagnetic activity, represented by (Kp) the planetary index or major geomagnetic storms (Dst) in the period, either on short or on long time scales. One suggested explanation associates the decrease in solar activity to the increased conductivity in the atmosphere caused by increase cosmic ray flux. Consequently there may be a reduction in the threshold voltage necessary to produce discharge atmospheric to cause failures in high-voltage grids. The global electric circuit described by the ionosphere-ground coupling (the electrosphere), plays an important role in explaining the reduction the failures. With increase in conductivity atmospheric discharges are less potent, resulting in fewer failures with the decreasing solar cycle
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica
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Filipovic-Gledja, Visnja. "A probability based unified model for predicting electrical, mechanical and thermal characteristics of stranded overhead-line conductors." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30086.pdf.
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Sechi, Daniel Luis, and Daniel Luis Sechi. "Planejamento da expansão da transmissão considerando a conexão de uma permissionária através de um método de apoio à decisão." Universidade Federal do Pampa, 2014. http://dspace.unipampa.edu.br:8080/xmlui/handle/riu/744.
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Este trabalho propõe um método de apoio à decisão aplicado ao problema do planejamento da expansão do sistema de transmissão de energia elétrica. O objetivo é investigar a influência de alguns atributos que são pertinentes para o planejamento das linhas de transmissão de 230 kV conectadas ao sistema interligado nacional (SIN), sob o ponto de vista de uma permissionária acessante. A motivação se deve ao fato que os modelos de planejamento mais utilizados no Brasil têm como estratégia considerar, no processo de expansão, somente os custos advindos de aspectos físicos e elétricos das linhas de transmissão, sem atribuir pesos e opiniões dos vários agentes (atores) do setor elétrico sobre outros aspectos menos tangíveis. Para tanto, busca-se inserir e avaliar um método de apoio à decisão como um elemento do processo de expansão do sistema de uma permissionária cooperativa do estado do Rio Grande do Sul. O impacto da adição deste método no planejamento será analisado e comparado com o estudo já realizado pela Empresa de Pesquisas Energéticas (EPE) na expansão desta permissionária. No estudo de caso, as alternativas propostas visam agregar situações que liberem a permissionária de contratos em 69 kV com outros agentes, de forma a minimizar custos com a conexão. Ou seja, diferentes traçados de linhas de transmissão em 230 kV são avaliados, a fim de suprir a conexão da permissionária, não satisfazendo somente critérios de custos com a implementação, mas também considerando aspectos técnicos e sociais da cooperativa.
This research aims to propose and test the technical feasibility of a decision support method applied to the problem of planning the expansion of the transmission of electricity in 230 kV system, a cooperative permittee of the state of Rio Grande South Similarly, the aim of this work is to investigate some attributes which are relevant to the planning of transmission lines (TL) of 230 kV connected to the national interconnected System (SIN). The motivation is due to the fact that models of planned expansion systems most used in Brazil as a strategy have to add, in the expansion process, almost only the physical and electrical transmission lines (TLs) aspects, without assigning weights & opinions planners of the electricity sector. To this end, we seek to enter and evaluate a method of decision support as an element of the system expansion process. The impact of adding this method in planning will be analyzed and compared with the study ever conducted by the Energy Research Company (EPE) in the expansion of permittee, in order to confirm and clarify the proposed methodology. Logo, citing that the alternative proposals aim to add situations that release the permittee contracts at 69 kV with agents of the electric power system, to minimize the connection costs. Ie different paths of transmission lines at 230 kV are proposed in order to supply the connection permittee, not only satisfying criteria of the implementation costs, but also considering environmental aspects partner.
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Visser, Abraham Johannes. "Transformerless series dip/sag compensation with a multilevel cascaded inverter." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52592.
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Thesis (MScEng)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: This thesis covers the development of a multilevel cascaded inverter for the purpose of costeffective transformerless series dip compensation. Of all known power quality problems, voltage dips are the greatest reason for concern. Dips/sags occur more frequently than outages and therefore tend to be more costly for industry as modem technical equipment becomes all the more sensitive to the quality and reliability of supply. A number of devices already exist to compensate for this problem, but the cost of most of these systems does not always justify the financial losses they compensate for. All of these systems are using transformers and/or large filter components that contribute to the size, price and losses to quite a large extent. Series injection dip compensators offer the advantage of only having to compensate for the decrease in supply voltage during a dip. This results in a significant reduction in the converter ratings and energy storage requirements compared to conventional uninterruptible power supplies or shunt injection power quality devices. Existing inverter topologies, including multilevel inverters, were therefore studied and compared as possible solutions for cost-effective transformerless series dip compensation. On the basis of these considerations the multilevel cascaded inverter seems to be the most cost-effective option. The relatively low harmonic content of its unfiltered output also eliminates the need for a large output filter. A single-phase dip compensator, with this topology, was designed and built according to specifications stated by Eskom, the main utility in South Africa. Batteries as energy storage and automotive MOSFETs as switching components, proved to be most cost-effective options for the specified power ratings. Control algorithms for dip compensation with the multilevel inverter were also developed. Some of these algorithms are based on existing techniques, but two new algorithms were also developed to implement force commutation of the thyristors and to share the power dissipation in the dip compensator. Simulations indicated that these algorithms could be suitable and sufficient for their application. This dip compensator with its control algorithms was tested with a dip generator, developed at the University of Stellenbosch, for different types of loads. The experimental results confirmed the simulations and showed a very good performance for the specified conditions. An optimised design of this dip compensator will make it a cost-effective solution for dip compensation.
AFRIKAANSE OPSOMMING: Hierdie tesis dek die ontwikkeling van 'n multivlakwisselrigter, in kaskade, met koste-effektiewe transformatorlose duik kompensasie as mikpunt. Van al die bekende toevoerkwaliteit probleme wek duike in die spanning die meeste kommer. Duike kom meer gereeld voor as kragonderbrekings en neig daarom om 'n groter onkoste te wees vir die industrie soos wat moderne tegnologiese toerusting al hoe meer sensitief raak vir die kwaliteit en betroubaarheid van die toevoer. 'n Aantal toestelle wat vir hierdie probleem kompenseer bestaan reeds, maar die koste van hierdie stelsels regverdig nie altyd die finansiële verliese wat hulle moet elimineer nie. Al hierdie stelsels gebruik transformators en/of groot filter komponente wat grootliks bydra tot die grootte, prys en verliese van hierdie stelsels. Serie-injeksie kompenseerders het die voordeel dat hulle net kompenseer vir die verlies in die toevoerspanning tydens die duik. Dit het 'n beduidende vermindering in die omsetterkenwaardes en energiestoorvereistes tot gevolg in vergelyking met ononderbroke kragbronne (UPS) of newe-injeksie toevoerkwaliteit toestelle. Daarom IS bestaande wisselrigtertopologië, insluitende multivlakwisselrigters, bestudeer en vergelyk as moontlike oplossings vir koste-effektiewe serie duik-kompensasie. Van al hierdie moontlikhede lyk die multivlakwisselrigter, in kaskade, na die mees koste-effektiewe opsie. Die relatiewe lae harmoniese inhoud van sy ongefilterde uittree elimineer die behoefte aan 'n groot uittreefilter. 'n Enkelfase duik kompenseerder, met hierdie topologie, is ontwerp en gebou volgens die spesifikasies wat vasgestel is deur Eskom, die hoof elektriese kragvoorsiener in Suid-Afrika. Dit het geblyk dat batterye, en MOSFETte uit die motorbedryf, die mees koste-effektiewe opsies bied vir onderskeidelik die energiestoor en skakelkomponente. Beheeralgoritmes VIr duik kompensasie met die multivlakwisselrigter is ook ontwikkel. Sommige van hierdie algoritmes is gebaseer op bestaande tegnieke, maar twee nuwe algoritmes is ook ontwikkel vir die kommutering van die tiristors en die deling van die drywingsverkwisting in die duik kompenseerder. Simulasies dui aan dat hierdie algoritmes geskik en voldoende kan wees vir hulle toepassing. Hierdie duik kompenseerder met sy beheeralgoritmes is getoets vir verskillende tipes laste met 'n duikgenerator wat ontwikkel is by die Universiteit van Stellenbosch. Die eksperimentele resultate bevestig dit wat verkry is uit die simulasies en wys 'n goeie werkverrigting vir die gespesifiseerde kondisies. 'n Geoptimeerde ontwerp van hierdie duik kompenseerder sal dit 'n koste-effektiewe oplossing maak vir duik kompensasie.
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Pinto, André Jinno Gomes 1983. "Análise dos parâmetros elétricos e transitórios eletromagnéticos de linhas de transmissão compostas por torres com altura elevada." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259379.
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Orientador: José Pissolato FilhoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: As redes de transmissão de energia elétrica estão entre as grandes contribuições que a engenharia ofereceu à civilização moderna. Se tornando aparentes, pelas expressivas linhas de transmissão de alta tensão apoiadas sobre elevadas torres de aço que cruzam o território nacional em todas as direções. No corrente trabalho tem-se por objetivo tratar das alternativas não-convencionais de transmissão de energia elétrica. Comparando o desempenho dessas novas estruturas com o comportamento das estruturas atualmente utilizadas no sistema de transmissão convencional. Para tal são descritos alguns dados da atual configuração do sistema de transmissão nacional. Ademais, breves descrições técnicas serão apresentadas sobre os principais componentes de linhas de transmissão convencionais, tais como: condutores múltiplos, isoladores e anéis anticorona. Tais definições serão introduzidas com o âmbito de proporcionar uma maior familiaridade com o tema em estudo. Uma análise minuciosa é traçada no cálculo dos parâmetros elétricos na frequência, seguido de um estudo dos transitórios eletromagnéticos no domínio do tempo. Causados por sinais de tensão aplicados a entrada das linhas de transmissão
Abstract: The transmission of electric energy is among the great contributions that engineering offered to modern civilization. Becoming apparent, by the expressive lines of high voltage transmission supported on large steel towers that crisscross the country in all directions. In the current work has been aimed at dealing with alternative non-conventional electric power transmission. Comparing the performance of these new structures with the behavior of the structures currently used in conventional transmission system. For such thing are described some of the current configuration of the national transmission system. In addition, brief technical descriptions are presented on the main components of conventional transmission lines, such as multiple conductors, insulators and anti-corona rings. Such definitions will be introduced to the scope of providing a greater familiarity with the subject under study. A detailed analysis is plotted on the calculation of electrical parameters on frequency, followed by a study of electromagnetic transient time domain. Caused by voltage signals applied to the input of the transmission lines
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica
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Pinto, André Jinno Gomes 1983. "Modelagem de torres de transmissão utilizando análise numérica dos campos eletromagnéticos e funções racionais." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260916.
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Orientadores: José Pissolato Filho, Eduardo Coelho Marques da CostaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: A análise do comportamento dinâmico da torre de transmissão de energia elétrica e torres de telecomunicações é de interesse nos estudos de proteção relacionados com descargas atmosféricas. Normalmente, a impedância de surto da torre no domínio do tempo é usada para caracterizar o comportamento dinâmico da torre. A principal desvantagem na definição de tais impedâncias de surto é a dependência da forma de onda de excitação, e não há consenso sobre a forma de onda de corrente a ser usada. Além disso, não há concordância sobre uma definição única da tensão envolvida. A fim de contornar tais limitações e problemas, o modelo aplicado ao estudo faz uso das análises no dominio da frequência, onde a impedância de surto da torre depende somente da geometria da estrutura e das características eletromagnéticas do meio. Ademais, as limitações associadas com as abordagens simplificadas são enfatizadas no decorrer do presente trabalho. Os resultados apresentados fazem uso de ferramentas computacionais como o código NEC-2 (Numerical Electromagnetic Code) que se baseia na análise numérica da dinâmica do campo eletromagnético. Com a utilização desse código, correntes são geradas e posteriormente utilizadas para o cálculo da impedância de surto da torre. Posteriormente, é gerado um circuito RLC representativo das características da estrutura metálica, obtidas pelo método de vector fitting que aproxima a função impedância de surto da torre por funções racionais. Por fim, o circuito RLC gerado pode ser aplicado nas análises diretamente no domínio do tempo com o uso de programas computacionais como o EMTP (Electromagnetic Transients Program), sem a necessidade do uso de transformadas para alterar o domínio de análise
Abstract: The dynamic analysis of the behavior in power transmission towers and telecommunications towers is of interest in studies related to lightning protection. Normally, the surge impedance of the tower in the time domain is used to characterize the dynamic behavior of the tower. The main disadvantage of these definition of surge impedances is the dependence on the waveform of excitation, and there is no consensus on which current wave to be used. Furthermore, there is no agreement on a single definition of the voltage involved. In order to overcome such limitations and problems, the model applied to the study makes use of the analysis in the frequency domain, where tower¿s surge impedance depends only on the geometry of the structure and electromagnetic characteristics of the medium. Moreover, the limitations associated with the simplified approaches are emphasized in the course of this work. The results presented make the use of computer code as NEC-2 (Numerical Electromagnetic Code) based on the numerical analysis of the electromagnetic field dynamics. Using this code, currents are generated and then used to calculate the surge impedance of the tower. Subsequently, an RLC circuit is generated representating the characteristics of the metal structure, obtained by vector fitting method, that approximates the surge impedance function of the tower by means of rational functions. Finally, the generated RLC circuit can be applied directly in analyzes in the time domain using computer programs such as EMTP (Electromagnetic Transients Program) without the need of using transforms to change domain analysis
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica
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Hellstenius, Ebba, and Nils Johansson. "Implementation of Wind- and Hydropower in Electrical Grids in Dalarna." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-293880.
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These days more renewable energy sources are beingintegrated into the power system, while nuclear power and otherconventional energy sources are being demounted. This comeswith some obstacles, e.g. the renewable energy sources do nothave the same ability to produce reactive power as conventionalenergy sources do. The purpose of this study is to investigate howthe voltage in a power grid would behave with only renewableenergy sources as generators. A fictive power grid was madeto represent a real power grid based in the region of Dalarna,Sweden. Maintain a stable voltage by only using wind andhydropower was the goal of the study, but also to have an self-sufficient grid that does not have to import power from nearbyregions. By using numerical analysis in Matlab with real data,the grid was simulated. The result was that the fictive grid wasnot able to be entirely self-sufficient as it had to import powerfrom nearby regions. In the constructed grid the voltage neverdeviated more than 1 % from the nominal voltage. In conclusion,the study fulfilled all the goals other than making it independent.Dessa dagar integreras fler förnybara energikällor i elnätet medan kärnkraft och andra konventionella energikällor demonteras. Detta kommer med några hinder, t.ex att de förnybara energikällorna inte har samma förmåga att producera reaktiv effekt som de konventionella energikällorna kan. Syftet med denna studie är att undersöka hur spänningen i ett elnät skulle uppföra sig med endast förnybara energikällor som generatorer. Ett fiktivt elnät skapades för att representera ett verkligt nät baserat i en region i Dalarna, Sverige. Att ha en stabil spänning genom att bara använda vind- och vattenkraft var studiens syfte, men också att nätet skulle vara självförsörjande och inte behöva importera effekt från grannområdena. Genom att använda numerisk analys i Matlab med verkliga värden simulerades nätet. Resultatet var att det fiktiva nätet inte kunde vara helt oberoende eftersom det var tvunget att importera effekt från de närliggande regionerna. Spänningarna i det konstruerade nätet avvek aldrig mer än 1 % från den nominella spänningen. Sammanfattningsvis uppfyllde nätet alla mål förutom att göra det självförsörjande.
Kandidatexjobb i elektroteknik 2020, KTH, Stockholm
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Zuboraj, MD R. "Coupled Transmission Line Based Slow Wave Structures for Traveling Wave Tubes Applications." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1477947681829031.
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Hobdell, Stephen Barry. "Thermally stimulated current and electrokinetic investigations of HV cable models." Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311421.
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Oliveira, Fábio Gabriel de. "Estudo de instalações de linhas subterrâneas de alta tensão com relação a campos magnéticos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-20102010-165349/.
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Atualmente, a intensidade de campo elétrico, campo magnético e campo eletromagnético é um fator determinante não só para a implantação de novas instalações, mas também, para as instalações existentes no sistema elétrico. Apesar de não existir nenhum estudo conclusivo que comprove a evidência direta entre a exposição a estes campos e os efeitos nocivos na saúde das pessoas, muitos países, inclusive o Brasil, definiram em suas legislações limites básicos à exposição de campos elétrico e magnético provenientes dos sistemas elétricos. Este trabalho tem como objetivo contribuir para análise de campo magnético de linhas subterrâneas de alta tensão existentes ou linhas em fase inicial de projeto, visando atender os limites de exposição vigentes na legislação local. Nele é apresentada a metodologia de cálculo de campo magnético baseada na Lei de Biot-Savart e no princípio da superposição. Estudos analíticos para verificação da influência dos parâmetros de instalação e elétricos de linhas sobre o campo magnético são apresentados para linhas subterrâneas de alta tensão compostas por um e dois circuitos com diferentes tipos de instalação e aterramentos. Comparações entre valores analíticos e valores de medições de campo magnético de linhas subterrâneas de alta tensão existentes em operação também são abordadas neste trabalho. As principais técnicas de mitigação de campo magnético utilizadas em linhas subterrâneas de alta tensão, tais como técnicas de compensação envolvendo laços de cabos e técnicas de blindagens com materiais metálicos externos aos cabos, também são apresentadas. Devido ao campo elétrico externo ao cabo isolado ser praticamente zero, assuntos referentes a este campo não são abordados neste trabalho. Por simplicidade, campo magnético refere-se à densidade de fluxo magnético neste documento.Nowadays, the intensity of electric field, magnetic field and electromagnetic field is a determining factor, not only for implantation of new installations, but also for existing installations in the power system. Although no exist conclusive study that proves the direct evidence between exposure to these fields and adverse effects on human health, many countries, including Brazil, have defined in their laws basic limits for exposure to electric and magnetic fields produced by the electric system. This work aims to contribute to analysis of magnetic field for both existing high voltage underground lines and lines in initial stage of project, aiming the actual exposure limits of the local legislation. In it, is shown the magnetic field calculation methodology based on the Biot-Savart\'s law and the superposition principle. Analytical studies to verify the influence of installation and electrical parameters of lines on the magnetic field are presented for high voltage underground lines consist of one and two circuits with different types of installation and earthing. Comparisons between analytical and measurement values of magnetic field of existing high voltage underground lines in operation are also addressed in this work. The main mitigation techniques of magnetic field used in high voltage underground lines, such as compensation techniques by loop of cables and shielding by metallic materials, are also presented. Due the electric field outside the insulated cable be practically zero, issues related to the electric field are not addressed in this work. For simplicity, the magnetic field refers to the magnetic flux density in this document.
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Talaisys, Jonas Lemos. "Conteúdo harmônico e estimativa da variação de comprimento de arcos elétricos gerados artificialmente em linhas de transmissão = Harmonic content and estimation of length variation of artificially generated electrical arc in transmission lines." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259600.
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Orientador: Maria Cristina Dias TavaresDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Este trabalho apresenta resultados do estudo do conteúdo harmônico e da variação do comprimento de arcos elétricos longos, com comprimento inicial superior a 4 m. Os resultados decorreram da análise de uma grande quantidade de dados obtidos de 647 ensaios realizados em ambiente não confinado em um trecho experimental de linha de transmissão aérea de 500 kV. Diversos níveis de corrente de arco foram abrangidos, desde 15 Aef até 10.000 Aef. O conteúdo harmônico da tensão e da corrente dos arcos foi analisado através da Trans-formada de Fourier Discreta em Tempo Reduzido. Mediante um tratamento estatístico, este conteúdo harmônico possibilitou a consolidação da assinatura harmônica dos arcos estudados. Uma contribuição importante da pesquisa consiste na verificação de que o conteúdo harmônico do arco pode ser utilizado para identificar o momento a partir do qual o arco elétrico se encontra com suas características elétricas estabilizadas. A partir deste instante os parâmetros elétricos do arco podem ser utilizados para obtenção de um modelo matemático. Utilizando-se do conteúdo harmônico e de registros visuais, a variação de comprimento foi obtida para 69 arcos. Esta análise inicial permite que se tenha uma noção da velocidade de alongamento destes arcos em relação ao seu nível de corrente. Permitiu também a obtenção de um gradiente de tensão mais preciso dos arcos, considerando-se tanto o alongamento quanto a estabilidade destes. Por fim, este trabalho tem por objetivo apresentar resultados que forneçam características e informações relevantes à obtenção de um modelo matemático de arco elétrico secundário adequado para o estudo da Manobra de Abertura e Religamento Monopolar. O conteúdo harmônico é identificado como uma ferramenta eficaz para caracterização da estabilidade destes arcos e o alongamento é um dos principais fatores relacionados com a extinção e duração do arco secundário
Abstract: This document presents results related to harmonic content and length variation of long electrical arcs in air, with initial length of 4 m. The results are based in the analysis of a data-base containing 647 experiments in non-confined environment of an experimental aerial 500 kV transmission line. The current range analyzed lies between 15 Arms and 10,000 Arms. The harmonic contents of voltage and current of electrical arcs were analyzed by the Short Time Discrete Fourier Transform. Using a statistic treatment this harmonic content allowed to consolidate the harmonic signature of the arcs in study. Furthermore, in the present work it was proposed that the harmonic content of an electrical arc defines the moment when the electric arc has its electrical characteristics stabilized. This instant is crucial to obtain the correct arc electrical parameters that will used to represent the arc. Using the harmonic content and visual data, the variation in length was obtained for 69 arcs. This initial analysis lead to arc elongation velocity regarding the current level and permit-ted to obtaining a more precise arc voltage gradient, considering both elongation as its stability. Finally, this work aims to supply relevant characteristics and information to obtaining a secondary arc model useful to the Single-Phase Autoreclosing Maneuver study. The harmonic content is an efficient way to characterize these arcs and the arc elongation is one of the main factors related to the duration and self-extinction of the secondary arc
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica
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Fourie, Gerhardus Johannes. "10 kW L-Band planar power combiner." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/2690.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006.This thesis relates to the design and characterization of a 10 kW L-band power combiner consisting of 8 input ports. The design is implemented in a non-radial planar transmission line architecture and operates between 1.2 and 1.4 GHz. Because of the ultra high power requirements for the combiner, special attention is given to the power handling capabilities of the transmission lines and the other components involved. Simulated S-parameter models of connector to stripline transitions and a one to four-way junction, as well as measured S-parameter models of high power terminations are incorporated in the final design. A 10 kW combiner was built and measured at low power only due to time constraints and the limited availability of high power sources. Satisfactory results were obtained in terms of the graceful degradation of unit amplifiers, port mismatches and power combining efficiency.
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Uzelac, Lawrence Stevan. "A Multiple Coupled Microstrip Transmission Line Model for High-Speed VLSI Interconnect Simulation." PDXScholar, 1991. https://pdxscholar.library.pdx.edu/open_access_etds/4526.
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A model is presented which incorporates the advantages of a mixed mode simulation to characterize transmission line behavior in multiple coupled Transmission line systems. The model is intended for use by digital circuit designers who wish to be able to obtain accurate transmission line behavior for complex digital systems for which continuous time simulation tools such as SPICE would time prohibitive. The model uses a transverse electromagnetic wave approximation to obtain solutions to the basic transmission line equations. A modal analysis technique is used to solve for the attenuation and propagation constants for the transmission lines. Modal analysis done in the frequency domain after a Fast Fourier Transform of the time-domain input signals. Boundary conditions are obtained from the Thevinized transmission line input equivalent circuit and the transmission line output load impedance. The model uses a unique solution queue system that allows n-line coupled transmission lines to be solved without resorting to large order matrix methods or the need to diagonals larger matrices using linear transformations. This solution queue system is based on the method of solution superposition. As a result, the CPU time required for the model is primarily a function of the number of transitions and not the number of lines modeled. Incorporation of the model into event driven circuit simulators such as Network C is discussed. It will be shown that the solution queue methods used in this model make it ideally suited for incorporation into a event-driven simulation network. The model presented in this thesis can be scaled to incorporate direct electromagnetic coupling between first, second, or third lines adjacent to the line transitioning. It is shown that modeling strictly adjacent line coupling is adequate for typical digital technologies. It is shown that the model accurately reproduces the transmission line behavior of systems modeled by previous authors. Example transitions on a 8-line system are reviewed. Finally, future model improvements are discussed.
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Mahiddini, Florian. "Modélisation couplée Compatibilité Électromagnétique - Thermique d’architectures de câblages électriques embarquées." Thesis, Toulouse, ISAE, 2018. http://www.theses.fr/2018ESAE0007/document.
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Le développement d’aéronefs « plus » voire « tout » électriques a pour conséquence la conception d’architectures électriques embarquées de plus en plus complexes entraînant une très nette augmentation du nombre de câbles électriques à déployer au sein des véhicules. Parmi les contraintes rencontrées lors des phases de définition et d’intégration des réseaux de câblages, les aspects de compatibilité électromagnétique et de gestion des échauffements thermiques deviennent de plus en plus critiques. Ainsi, ces travaux de thèse sont dédiés au développement d’une méthodologie permettant la prédiction d’une part, des courants induits par et sur les réseaux de câblages et d’autre part, de leur niveaux d’échauffement. En particulier, l’analyse bibliographique effectuée à cette occasion montre que les phénomènes électrostatiques (à la base de la théorie des lignes de transmission) et de conduction stationnaire de la chaleur sont strictement analogues, ce qui autorise une résolution simultanée de ces deux problèmes pour les réseaux de câblages considérés. Les présents travaux démontrent que le calcul des paramètres électriques primaires (p.u.l) du réseau et de la distribution de température dans le plan transverse peut se faire de manière totalement couplé à l’aide d’un schéma numérique basé sur la Méthode des Moments(MoM). Le choix de l’utilisation des équations intégrales pour la résolution de ce problème de potentiel se fonde sur plusieurs avantages tels qu’une utilisation optimisée des ressources de calcul et l’utilisation d’algorithmes efficaces de résolution, de surcroît naturellement parallélisables pour de futurs développements. Les outils de calculs thermiques développés dans le cadre de cette thèse, et qui ont vocation à être intégrés dans la suite logicielle CRIPTE de l’ONERA, ont fait l’objet d’une validation expérimentale pour plusieurs configurations de harnais électriques. Les comparaisons simulations-mesures présentent de bons accords bien que les expérimentations menées aient montré la difficulté d’obtenir précisément des valeurs du coefficient d’échange thermique,même dans des conditions parfaitement maîtrisées. Les travaux ouvrent enfin des perspectives nouvelles sur l’optimisation en terme de masse des réseaux de câblage (EWIS)The on-going development of “more” or “all” electrical aircraft leads to the design of ever-complex embeddedelectrical networks, which causes a significant increase of electrical cables to be used within these innovativevehicles. Among the constraints encountered during the definition and integration phases of the network, thoserelated to the electromagnetic compatibility between equipment as well as the management of thermal heatingby Joule’s effect become more and more stringent. Thus, this thesis is dedicated to the development of anoriginal methodology enabling the prediction of both induced and crosstalk currents as well as the heating upstate in complex bundles of cables. Indeed, literature review explicitly shows that electrostatic and stationaryheat transfer phenomena are, from a mathematical standpoint, strictly the same which allows the simultaneouscomputation of these two problems for an arbitrary network. This research work demonstrates that the determinationof primary electrical parameters (per unit length) and the temperature distribution within a givencross-section can be handled with the numerical Method Of Moment (MoM). This choice is motivated by theseveral inherent advantages of the method like an optimized use of the computer resource and the naturalparallelization of the algorithms. The developed numerical tools, intended to be fully integrated in the in-housesoftware suite CRIPTE, has been validated during an experimental campaign that has involved several typesof bundles. Although the comparisons between experimental and simulated results comply with each other,experiments reveal the hard task of getting a precise estimation of the heat transfer coefficients, even in awell-controlled environment. Finally, these works open new and very promising perspectives for future EWIS(Electrical Wiring Interconnection System) in term of mass optimization
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SAFRA, LEANDRO C. P. G. "Obtenção de fios em ligas de cobre para utilização em linhas de transmissão e em eletrodos para contatos elétricos." reponame:Repositório Institucional do IPEN, 2011. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10052.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Najafi, Syed Ahmed Ali. "Energy Harvesting From Overhead Transmission Line Magnetic Fields." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1548448189459464.
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Mestas, Valero Patricia. "Controle adaptativo para religamento tripolar aplicado a linhas de transmissão com compensação reativa em derivação." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260992.
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Orientador: Maria Cristina Dias TavaresTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: O presente trabalho descreve um novo método de controle adaptativo para chaveamento sincronizado de disjuntores durante a manobra de religamento tripolar de linhas de transmissão com compensação reativa em derivação. O objetivo principal do método desenvolvido é controlar as sobretensões transitórias e reduzir o tempo morto antes do religamento. Diferentes estratégias para controlar sobretensões decorrentes do religamento tripolar são descritas com a finalidade de diferenciar as vantagens do chaveamento sincronizado. Os benefícios potenciais a serem obtidos a partir do religamento tripolar rápido são expostos. O método de controle adaptativo desenvolvido consiste em identificar com antecedência a região ótima para o religamento, permitindo fechar o disjuntor já no primeiro mínimo do batimento da tensão entre os contatos do disjuntor após o tempo morto de atuação da proteção. Após os testes realizados utilizando um programa para simulação de transitórios eletromagnéticos (PSCAD/EMTDC), o método proposto foi implementado em protótipo (controlador). Este protótipo foi testado utilizando o Simulador Digital em Tempo Real (RTDS). As simulações em tempo real demonstraram a eficiência do método no controle das sobretensões e na redução do tempo morto. Finalmente, o método foi avaliado parametricamente para uma série de condições simuladas, incluindo diferentes níveis de compensação reativa em derivação, a influência da compensação série, a influência da transposição da linha de transmissão e os efeitos da variação do comprimento da linha. Além disto, outras simulações foram realizadas para comparar o desempenho dos métodos de controle existentes e do método proposto
Abstract: The present thesis describes a new adaptive control method for synchronous switching of circuit breakers during three-phase reclosing of shunt compensated transmission lines. The main objective of the developed method is to control the overvoltages and to reduce the dead time prior of reclosing. Several strategies to control overvoltages resulting from three-phase reclosing are described in order to differentiate the benefits of the proposed method. The potential benefits obtained from the developed controlled reclosing method are exposed. The proposed algorithm identified, in advance, the optimal region for reclosing of transmission line, allowing closing the circuit breaker at the first minimum voltage beat across circuit breaker, after protection dead time. After off-line testing using electromagnetic transients simulation program (PSCAD/EMTDC), the proposed method was also implemented in physical hardware. This hardware was then tested on a real-time transients simulator (RTDS). The real time simulations demonstrate the method efficiency to control overvoltages and to reduce the dead time. Finally, the method has been parametrically evaluated for a range of simulated conditions, including different shunt compensation levels, influence of series compensation, influence of transmission line transposition, effect of line lengths. In addition, simulations have been conducted to compare the performance of existing control method and the proposed method
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica
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Almeida, Venicio Ferreira de. "Metodologia para avaliar o impacto de técnicas de repotenciação no desempenho de linhas de transmissão em regime permanente." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-10122013-093636/.
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O presente trabalho tem como objetivo propor uma metodologia para avaliar o impacto das diversas técnicas de repotenciação no desempenho de linhas de transmissão em regime permanente, visto que na atual literatura não existe uma análise abrangente que possa ser aplicada em qualquer linha de transmissão carente de repotenciação. A metodologia busca fornecer subsídios para escolha da técnica mais vantajosa para repotenciar uma linha, utilizando de forma extensiva, os fatores de desempenho, e de forma sintetizada, os índices de mérito agregado, que, avaliados individualmente e/ou em conjunto, propiciam informações qualificadas para as conclusões técnicas. Destaca-se que a proposição dos fatores de desempenho e dos índices de mérito são as principais contribuições deste trabalho. Para complementar a metodologia, uma análise de curtos-circuitos foi proposta. Os resultados da utilização da metodologia foram positivos, possibilitando verificar os ganhos de potência na transmissão de energia. Vale destacar a eficiência dos índices de mérito agregado, que identificaram a melhor técnica de repotenciação de forma sintetizada, resguardando a qualidade e enquadramento dos resultados nas normas regulamentadoras.This work aims at proposing a methodology to assessing the impact of power upgrade techniques on the steady-state performance of transmission lines, since there is not anything similar to this in the technical literature. The proposed methodology aims at providing technical information to subside the choice of the best power line upgrade technique, by the extensive application of the performance factors and of the aggregate merit indices. It must be pointed out that the proposition of the performance factors and of the aggregate merit indices are the main contributions of this work. Additionally, a short circuit analysis was also proposed to assess the power upgrade techniques. The results after the method application were satisfactory and allowed verifying the surplus of power related to each upgrade technique. The contribution of the aggregate merit indices was very important to identifying the most favorable upgrade technique in a simple way, so that all statutory technical limits were not violated.
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Mbairi, Felix D. "Some Aspects of Advanced Technologies and Signal Integrity Issues in High Frequency PCBs, with Emphasis on Planar Transmission Lines and RF/Microwave Filters." Doctoral thesis, KTH, Mikroelektronik och tillämpad fysik, MAP, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4324.
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The main focus of this thesis is placed on high frequency PCB signal Integrity Is-sues and RF/Microwave filters using EBG structures. From the signal Integrity aspect, two topics were mainly discussed. On one hand, the effect of increasing frequency on classical design rules for crosstalk reduction in PCBs was investigated experimentally and by full-wave simulations. An emphasis was placed on the 3×W spacing rule and the use of guard traces. Single-ended and differential transmission lines were considered. S-parameter measurements and simu-lations were carried out at high-frequency (up to 20 GHz). The results emphasize the necessity to reevaluate traditional design rules for their suitability in high frequency applications. Also, the impacts of using guard traces for high frequency crosstalk re-duction were clearly pointed out. On the other hand, the effect of high loss PCB ma-terials on the signal transmission characteristics of microstrip lines at high frequency (up to 20 GHz) was treated. Comparative studies were carried out on different micro-strip configurations using standard FR4 substrate and a high frequency dielectric ma-terial from Rogers, Corporation. The experimental results highlight the dramatic im-pact of high dielectric loss materials (FR4 and solder mask) and magnetic plating metal (nickel) on the high frequency signal attenuation and loss of microstrip trans-mission lines. Besides, the epoxy-based SU8 photoresist was characterized at high frequency (up to 50 GHz) using on-wafer conductor-backed coplanar waveguide transmission lines. A relative dielectric constant of 3.2 was obtained at 30 GHz. Some issues related to the processing of this material, such as cracks, hard-skin, etc, were also discussed. Regarding RF/Microwave filters, the concept of Electromagnetic Band Gap (EBG) was used to design and fabricate novel microstrip bandstop filters using periodically modified substrate. The proposed EBG structures, which don’t suffer conductor backing issues, exhibit interesting frequency response characteristics. The limitations of modeling and simulation tools in terms of speed and accuracy are also examined in this thesis. Experiments and simulations were carried out show-ing the inadequacies of the Spice diode model for the simulations in power electronics. Also, an Artificial Neural Network (ANN) model was proposed as an alternative and a complement to full-wave solvers, for a quick and sufficiently accurate simulation of interconnects. A software implementation of this model using Matlab’s ANN toolbox was shown to considerably reduce (by over 800 times) the simulation time of microstrip lines using full-wave solvers such as Ansoft’s HFSS and CST’s MWS. Finally, a novel cooling structure using a double heatsink for high performance electronics was presented. Methods for optimizing this structure were also discussed.QC 20100809