Dissertations / Theses on the topic 'Power transmission line performance'
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Liang, Feng. "Performance enhancement of digital relays for transmission line distance protection /." Internet access available to MUN users only, 2003. http://collections.mun.ca/u?/theses,153681.
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Mukherjee, Tonmoy Shankar. "High performance, low-power and robust multi-gigabit wire-line design." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/39515.
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The object of this research is to develop robust wire-line systems which demonstrate high performance while simultaneously consuming low power. The main focus of this work is the Clock and Data Recovery (CDR) system, which is the primary circuit of any modern wire-line transceiver. Different techniques starting from circuit-level to system-level have been investigated in this work to improve the performance of multi-gigabit CDRs. A 62 GHz bandwidth amplifier has been presented to address the need for a scalable amplifier for CDR needs. A new technique has been proposed to improve the radiation immunity of latches, to reduce the BER in CDRs occurring due to package radiations. An injection-lock based clock recovery method was investigated as an alternative to PLL based CDRs as they can be used for burst-mode wire-line communication. The investigation yielded the vulnerability of the method to jitter (false-locking and high jitter transfer), the attenuation of which is critical to commercial CDRs. A novel false-lock detector system has been proposed and demonstrated for the first time as a robust solution to the issue of false-locking of CDRs due to repetitive patterns. The implementation of the final CDR system required the use of an L-C tank VCO, the components of which are generic for all commercial CDRs. A new systematic layout technique for the VCO has been proposed and demonstrated in this work to substantially improve the layout area and the associated parasitics, approximately by 70 %. This new layout addresses a critical yet often neglected part of VCO design. Furthermore, a new concept has been proposed to optimize static dividers with respect to their power consumption and number of devices.
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Mthunzi, Everett Mondliwethu. "Performance analysis of a protection scheme based on P-class synchrophasor measurements." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2378.
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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016.Power grid and system protection advancement greatly depend on technological advances. Advent technologies like digital microprocessor type protective relays facilitate paradigm shifts, providing inimitable beneficial engineering adaptations. Phasor measuring technology provides one such technological advance. The onset and rapid development of the Phasor Measuring Unit (PMU) provides an excellent platform for phasor-based, power system engineering. Power transmission constitutes a critical section in the electric power system. The power system transmission lines are susceptible to faults which require instant isolation to establish and maintain consistent system stability. This research focuses on the study of transmission line protection based on P-Class synchrophasor measurements. The IEEE C37.238-2011 Precision Time Protocol (PTP) paradigm shift facilitates practical application of synchrophasors in protection schemes. Synchrophasor procession and accurate data alignment over wide areas support the hypothesis of a phasor-based transmission line differential protection. This research aims to directly implement P-Class synchrophasors in transmission line differential protection, employing synchrophasors to determine fault conditions and administer corresponding protective actions in wide area transmission lines. The research also aims to evaluate the operational characteristics of the synchrophasor-based transmission line differential protection scheme. The research deliverables include a laboratory scale Test-bench that implements the PMU-based transmission line differential protection scheme, and a differential protection utility software solution that follows guidelines specified by the C37.118-2011 standard for synchrophasors. The findings stand to evaluate performance of the PMU-based line differential protection scheme, verifying the protection model as an alternate, practical and feasible backup protection solution. The research deliverables include a synchrophasor-based current differential algorithm, software utility for implementing the PMU-based protection scheme and a Test-bench for concept and feasibility validation.
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Adebisi, Bamidele. "Broadband Transmission over indoor Power-line channels." Thesis, Lancaster University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.536027.
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Lu, Liping. "Performances and quality of service of PLC networks for MV and LV distribution systems." Thesis, Vandoeuvre-les-Nancy, INPL, 2006. http://www.theses.fr/2006INPL080N/document.
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In this thesis, we are interested in a wide-area PLC (Power Line Communication) network to provide a communication infrastructure for monitoring and control of energy distribution and consumption. This work has been carried out as a part of REMPLI (Real-time Energy Management via Power Line and Internet) European project and resulted in the definition of REMPLI PLC. For achieving high network performance and real-time data transfer using medium voltage and low voltage electricity grids, major problems such as dynamic packet routing, quality of service management and real-time event reporting are addressed. We designed an efficient routing protocol to cope with dynamic electricity grid topology changes and to relay packets to reach the destination. REMPLI PLC performance is evaluated using simulations and complemented by analytic studies. It is proved that most of the application requirements can be satisfied by REMPLI PLC. We proposed and implemented a new traffic dispatcher providing differentiated quality of service for applications. Based on ALOHA protocol, some variants have been designed and evaluated for enabling efficient real-time event notificationDans cette thèse, nous nous intéressons à la problématique liée à la communication numérique sur courant porteur dans l’objectif de fournir une infrastructure de communication qui permet la surveillance et le contrôle de la distribution et de la consommation de l’énergie. Ce travail a été effectué dans le cadre du projet européen REMPLI (Real-time Energy Management via Power Line and Internet) et a produit la spécification REMPLI PLC (Power Line Communication). Pour fournir une meilleure performance de la communication et effectuer le transfert de données en temps réel, en utilisant les réseaux électriques de moyenne tension et de basse tension, les problèmes principaux qui sont le routage dynamique de paquets de données, la gestion de la qualité de service et la notification des événement en temps réel, ont été traités. Nous avons développé un protocole de routage efficace pour s’adapter au changement dynamique de topologie du réseau électrique. Les performances de REMPLI PLC sont évaluées en utilisant des approches de simulation couplée avec des approches analytiques. Il est prouvé que la majorité des besoins applicatifs peuvent être satisfaite par REMPLI PLC. Nous avons proposé et implanté un nouvel “ordonnançeur de traffic” fournissant différents niveaux de qualité de service pour les applications. Des variantes de protocole ALOHA ont été proposées et évaluées afin de vérifier que les propriétés temps réel requises sur les notifications d’événements sont respectées
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Ahmeda, Mohammad. "Earthing performance of transmission line towers." Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/42730/.
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This work is primarily concerned with the performance of tower base earthing systems under AC variable frequency and transient conditions. The work has involved the investigation into the performance of practical earthing systems including tests on a full-size 275kV transmission tower base and corresponding calculation and numerical simulations.
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Alavi, Hessam. "Acoustics of high performance transmission-line loudspeakers." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/388041/.
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Acoustically treated, lined ducts are used in a wide range of applications, one of which is a transmission-line loudspeaker (TLL), which consists of a long, acoustically-lined, folded duct attached to the rear of the loudspeaker driver. Consequently, knowledge and understanding of sound propagation within acoustically treated ducts is essential in order to be able to create and analyse designs for the intended applications. The lowfrequency driver of a loudspeaker creates pressure fluctuations on both sides of the diaphragm. Therefore, a loudspeaker cabinet of some sort is required to control the sound radiation from the rear of the driver and to prevent the unwanted interference of those sounds with that radiated from the front of the loudspeaker. The transmission-line loudspeakers are however, designed and optimized to control this rear driver radiations by redirecting the pressure at the back of the driver and use them to extend the overall low-frequency response of the loudspeaker system. Transmission-line loudspeakers rely on the use of sound absorbing materials and, although attempts at modelling the performance of these have been reported in the literature, most transmission-line loudspeakers are designed empirically, using a combination of experience and trial-and-error. This project is concerned with creating and evaluating an engineering method of accurately modelling the sound propagating inside the transmission-line loudspeaker waveguides. Loudspeaker systems inherently suffer from an insufficient low-frequency response, due to their inefficiency at low-frequencies. Therefore, TLL rely on the use of sound absorbing materials added on their internal boundaries to extend their overall response of the loudspeaker at the lowfrequency region. The acoustic load on the driver and the sound radiated from the open end of the TLL duct both depend upon the propagation of sound through the duct; and the physical length of the duct determines the frequencies that can propagate within it. The addition of sound absorbing materials along the interior boundaries of the TLL reduces the speed of propagating sound within it, causing the TLL to respond such as having a much longer internal waveguide, consequently accommodating far lower frequencies within the TLL duct, extending the overall response of the loudspeaker system. The characteristics of sound propagation through a variety of two-dimensional and three-dimensional acoustically lined ducts at low-frequencies have been analyzed. Analytical models of straight ducts have been compared with the developed numerical models. In this research dissipative mufflers, that consist of ducts lined on the inside with an acoustically absorptive material, have been considered. Starting with the propagation of sound within hard-walled boundary condition ducts, this investigation moves to the modelling of waveguides treated with locally-reacting acoustic liners and next into the analysis of ducts treated with bulk-reacting acoustic absorbent materials; two kinds of excitations have been considered, namely pistonic and non-uniform excitation. The impedance mismatch and acoustic dissipation between the sound absorbing layer and the free propagation within the duct has been modelled numerically, and the results have been compared with the in-situ measurements conducted on a range of acoustically treated and purpose built transmission-line loudspeakers. A wide range of sound absorbing materials, namely fibrous and porous absorbers, have been characterized using their low-resistivity and acoustic impedance. Based on their individual characteristics, acoustical optimization was applied on a simple geometry U-shaped TLL duct.
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Taylor, Gareth Andrew. "A high voltage transmission line for space power systems." Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315620.
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Chakrabarti, Abhimanyu. "Transmission line matrix modelling for semiconductor transport." Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338228.
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Chen, Dian. "Transmission line modelling (TLM) of physical systems." Thesis, University of Sheffield, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361632.
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Shen, Bin. "Analysis on adverse-weather-related power transmission line outages." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0017/MQ47093.pdf.
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Liu, Xiaopeng. "Power system dynamic vulnerability under extreme transmission line contingencies." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18782.
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Power systems around the world may be under the threat of extreme conditions such as natural disasters and terrorist attacks. To find the most severe condition in the static sense, systematic methods based on optimization have been developed. However, until now, there is no systematic way to find the most severe contingency in the dynamic sense. The thesis proposes such a systematic approach. The method adopts a two-step “screening-and-ranking” procedure similar to the one employed in conventional dynamic security analysis. In the “screening” step, transmission lines are screened using two criteria. The first criterion is based on critical eigen-sensitivity with respect to single line outages. A transmission line is selected only if one of the critical eigenvalues has a large sensitivity to the outage of this line. The second criterion is based on a topology analysis searching for cut-sets in the system. A transmission line is selected if it is a member of a system cut-set with high power imbalance ratio. In the “ranking” step, time-domain analysis is performed on all the combinations of the lines screened by the first step, to determine their real dynamic impact on the system. Relays for generators, loads, and transmission lines are set-up so as to capture possible cascading events after the initial disturbance. Test results on the One Area IEEE96 system show that the set of critical lines selected by the proposed screening scheme is dependent on the system operating conditions. The screening step can reduce the contingency number significantly, which will alleviate the computation burden in the ranking step by a large margin. The most severe contingencies in term of load shedding were in most cases identified by the proposed method. The merit of the method is its simplicity, which makes it applicable to the analysis of N-2 and N-3 transmission line contingencies. Limitations of the method, such as the possibility of missing the more disruptive cLes réseaux électriques peuvent être sous la menace de conditions extrêmes, tels que désastres naturels et attentats terroristes. Pour déterminer la condition la plus sévère en état stationnaire, des méthodes systématiques utilisant des techniques d'optimisations ont été développées. Jusqu'à présent il n'existe cependant pas de méthodes systématiques pour déterminer quel défaut est le plus sévère en régime dynamique. Cette thèse propose une telle méthode. Elle utilise une approche en deux étapes, « triage et classement », similaire à celle utilisée dans une analyse de sécurité dynamique conventionnelle. Dans l'étape de triage, les lignes de transport d'électricité sont sélectionnées selon deux critères. Le premier est basé sur la sensibilité critique des valeurs propres par rapport à la perte d'une seule ligne. Une ligne de transport est sélectionnée seulement si une des valeurs propres critiques a une sensibilité élevée à la perte de cette ligne. Le second critère est basé sur une analyse topologique et recherche des ensembles de coupure dans le système. Une ligne de transport est sélectionnée si elle appartient à un ensemble de coupure avec un déséquilibre de puissance élevé. Dans l'étape de classement, une analyse temporelle est effectuée sur toutes les combinaisons possibles des lignes de transport sélectionnées dans la première étape, afin de déterminer leurs véritables impacts dynamiques sur le réseau électrique. Les relais de protection sont représentés. Les résultats des simulations sur le système test IEEE96 démontrent que l'étape de triage peut réduire le nombre de défauts de manière significative, ce qui peut alléger considérablement le fardeau de calcul dans l'étape de classement. Les défauts les plus sévères en termes de délestage étaient identifiés dans la plupart des cas par la méthode proposée. L'intérêt de la méthode réside dans sa simplicité,$
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Mansour, Tony, and Majdi Murtaja. "Applied estimation theory on power cable as transmission line." Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-46583.
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This thesis presents how to estimate the length of a power cable using the MaximumLikelihood Estimate (MLE) technique by using Matlab. The model of the power cableis evaluated in the time domain with additive white Gaussian noise. The statistics havebeen used to evaluate the performance of the estimator, by repeating the experiment fora large number of samples where the random additive noise is generated for each sample.The estimated sample variance is compared to the theoretical Cramer Raw lower Bound(CRLB) for unbiased estimators. At the end of thesis, numerical results are presentedthat show when the resulting sample variance is close to the CRLB, and hence that theperformance of the estimator will be more accurate.
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De, Villiers Dirk I. L. "Analysis and design of conical transmission line power combiners." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/607.
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Shahri, Javad Yazdani Kohneh. "High frequency digital power line transmission for terrestrial and marine networks." Thesis, Lancaster University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288950.
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Keen, Alan G. "Planar transmission line analyses using the Method of Lines." Thesis, University of Kent, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293993.
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Patel, Hitesh Narhari 1970. "Self adjusting transmission line drivers for high performance systems." Thesis, The University of Arizona, 1993. http://hdl.handle.net/10150/278274.
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Output impedance matching for transmission line drivers is not easy to implement due to unavoidable process tolerances. An automatic system for adjusting the output impedance of fast CMOS drivers, on one chip, is described. The output impedance of all identical drivers is adjusted to match the impedance at the input of a reference transmission line, equal in geometry to the lines connected to the other drivers, by a circuit for measuring and correcting the mismatch between the output impedance of one of the drivers, taken as reference and dedicated for this purpose. The voltage measured at the far end of the reference line is sent to a differential amplifier where it is compared with the supply voltage of the final driving stage. According to the comparison result at specific time intervals, a signal is supplied to the regulator which supplies power to the penultimate driving stage, thereby controlling the resistance of the driver to match the line impedance. Simulations have shown that the percentage deviations of the far-end line voltage is approximately 3% for this design compared to a system without feedback which has a far-end line voltage deviation of approximately 18%.
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Shehab-Eldin, Elsayed Hassan. "Travelling wave distance measurement in E.H.V. power systems." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254446.
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Wilson, Colin Richard. "The design and development of fast pulsed power supplies using Transmission Line Transformers." Thesis, University of St Andrews, 1992. http://hdl.handle.net/10023/13600.
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This thesis is concerned with the development of Transmission Line Transfomer (TLT) pulsed power supplies and the generation of fast risetime (>50ns), good quality, high repetition-rate voltage pulses for flash x-ray preionisors and other applications. It explains the principle of the TLT and reports on two TLT pulsed power supplies that have been built. The first, or prototype, produced output voltage pulses with risetimes of 50ns and durations of 200ns and was used to power a flash x-ray preionisation source for a mercury bromide laser. The second, a 50kV, 100? device, was built as part of a wider research program concerned with the development of space based pulsed power supplies. The development of ceramic tile technology is also described and the relevant electrical, mechanical and thermal properties of some barium titanate tiles given; it is then shown how ceramic tiles can be used to construct compact pulse generators for TLT systems. Finally, the subject of nonlinear dielectric pulse sharpening is introduced and pulse sharpening in a delay line ladder network containing air-core inductors and non-linear capacitors is demonstrated. It is then explained how these lines can be used to improve the output risetime of a TLT.
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Baisden, Andrew Carson. "Modeling and Characterization of Power Electronic Converters with an Integrated Transmission-Line Filter." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/33188.
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In this work, a modeling approach is delineated and described in detail; predominantly done in the time domain from low frequency, DC, to high frequencies, 100 MHz. Commercially available computer aided design tools will be used to determine the propagation path in a given structure. Next, an integrated transmission-line filter â fabricated using planar processing technologies â is modeled to accurately predict the EMI characteristics of the system. A method was derived to model the filterâ s performance in the time-domain while accurately depicting the highly frequency dependant transmission-line properties. A system model of a power factor correction (PFC) boost converter was completed by using active device models for diodes, MOSFETs, and the gate driver. In addition, equivalent circuits were used to characterize high frequency impedances of the passive components.
A PFC boost converter was built and used to validate the model. The PFC operated at a peak output power of 1 kW, switching at 400 kHz, with a universal input ranging from 90-270 VRMS with unity power factor. The time-domain and EMI frequency spectrum waveforms are experimentally measured and agree very well with the simulated values; within 5 dB for EMI.
The transmission-line filter was also manufactured for model verification, and it is tested for the first time with an operating converter: a PFC at 50 W output and 50 VDC input. The small signal characteristics match the model very well. In addition, impedance interactions between the filter, the converter, and the EMI measurement set-up are discussed, evaluated, measured, and improved to minimize undesired resonances and increase low-frequency EMI attenuation. Experimentally measured attenuation provided by the filter in the range from 100 kHz to 100 MHz was 20-50 dBμV. The simulation also shows a similar attenuation, with the exception of one key resonance not seen in the simulation.Master of Science
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Roongsita, Somsak. "Simulation and study of harmonic interference in power line communications." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/101256.
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Power line carrier (PLC) is one of the communication and load control (C&LC) techniques employed in direct load control. A PLC is, within itself, a communication system. It utilizes power transmission line as a medium of transmitting control functions, and relaying. High frequencies, in the order of 30 to 300 kHz, are used. Power line carrier systems are, at present, the most attractive C&LC systems.
Recently, dispersed generation - photovoltaics, wind energy, small scale hydro - is introduced to power systems. The introduction of small scale dispersed generation sources degrades the performance of PLC systems by injecting dc-ac inverter related harmonics into the distribution lines. These harmonics interfere with PLC signals. Thus load control functions assigned to PLC systems are affected.
It is the purpose of this research to study how a PLC signal propagates through the transmission line and how it is affected by the harmonic interference. An experiment is conducted using a distribution network provided by the Jet Propulsion Laboratory discussions, and conclusions are presented.M.S.
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Abdelhalim, Hussein Mohamed. "Stability effects of frequency controllers and transmission line configurations on power systems with integration of wind power." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78461.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 52-53).
This thesis investigates the stability effects of the integration of wind power on multi-machine power systems. First, the small-signal stability effects of turbine governors connected to synchronous generators in the presence of large-scale penetration of wind and load power disturbances are analyzed. Results suggest that tuning the turbine governors when wind power generation is present can improve the small-signal stability of an interconnected system. Then, the transient stability effects of integrating doubly-fed induction wind turbine generators through different transmission line configurations and at different buses are analyzed. Results show that connecting the wind through transmission lines and to different buses introduces a delay in the oscillatory response of the synchronous generator speed, and bus voltage oscillations are also affected. Results also show that there is no significant effect on the base cases when using different interconnection voltages to connect the wind. Overall, the results can be used by power system operators when making decisions on turbine governor tuning and transmission line configurations when connecting wind farms to existing power systems while optimizing for small-signal and transient stability response.
by Hussein Mohamed Abdelhalim.
S.M.
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Kirawanich, Phumin. "Fuzzy logic control for an active power line conditioner /." free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060114.
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Chen, Yaow-Ming. "Active power line conditioner with neural network control /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841132.
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Lahmar, Mustafa. "ESTIMATION OF TRANSMISSION LINE PARAMETERS USING LINEAR METHOD WITH SYNCHRONIZED AND UNSYNCHRONIZED DATA." UKnowledge, 2019. https://uknowledge.uky.edu/ece_etds/135.
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Accurate value of transmission line parameters is important for power system protection applications, especially for distance relays whose zone settings are based on positive sequence line impedance. The research is devoted to estimating transmission line positive-sequence parameters from synchronized or unsynchronized measurements of voltage and current phasors that are obtained at both terminals of the line. The positive sequence parameters including series impedance and shunt admittance can be linearly estimated. The linear least square algorithm has been derived in this dissertation for different transmission line configurations. The algorithm is able to handle both synchronized and unsynchronized measurements and deal with potential synchronization errors by explicitly modeling the synchronization angle. Sample results are reported to demonstrate the effectiveness of the proposed method.
Three types of transmission line models depending on line length (long, medium and short) are studied in this dissertation. Chapter 3 uses unsynchronized data for the long transmission line. The derived method can detect the unsynchronized angle and estimate the positive sequence of long line parameters. The proposed method is examined with negative impacts such as errors on currents and voltages data. These errors are added randomly to one set each time to test the robustness of the developed algorithm.
The medium transmission line algorithm derivation is presented in chapter 4. This chapter uses a linear least square to estimate the lumped parameters of a medium transmission line. The two different transmission line circuits are used to model the medium line. The first circuit is a single transmission line with two nodes and is used to evaluate the developed algorithm. The second circuit is a double transmission line. These two lines can have the same or different line parameters or line length. The developed algorithm shows that the proposed method achieves highly accurate results for the estimation of positive sequence line parameters.
The short transmission line is studied in chapter 5. The short transmission line uses less data than the long or medium lines because in this model the shunt capacitance is omitted. Thus, the linear estimation yields highly accurate results. Case studies are considered to test the robustness of this developed method.
The line temperature mainly affects the series resistance, and the developed algorithms in previous three chapters can accurately estimate the transmission line parameters. To simplify the real-time estimation of line resistance and temperature, the series inductance, and shunt capacitance can be treated as constant and known values. Chapter 6 provides such studies of estimating resistance by treating inductance and capacitance as known values.
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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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Bridgeman, M. "Algorithms for on-line measurement of harmonic damping and avoidance of harmonic resonances due to power factor capacitor switching in distribution systems." Thesis, Staffordshire University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272760.
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Beyers, Ryno Dawid. "Circuit model design of conical transmission line power combiners and isolation of reactive combiners." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96976.
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Thesis (PhD)--Stellenbosch University, 2015.ENGLISH ABSTRACT: This dissertation presents a circuit-based design technique that leads to benefits in terms of the physical size, manufacturability, and exibility in the design of N-way conical line power combiners. An equivalent circuit model for the peripheral input ports of conical line power combiners is extracted, as well as empirical equations that allow the circuit element values to be calculated directly from the physical dimensions of the combiner, and vice versa. This allows for rapid optimization of various dimensions of the combiner at a significantly reduced computational cost compared to full-wave simulations. A design procedure is presented and a conical combiner designed with a measured reflection coefficient of better than -18 dB over a 46 % bandwidth around 10 GHz. The designed prototype is much smaller compared to previous designs while exhibiting similar performance. Design procedures for single-section and multi-section impedance tapered conical to coaxial line transitions are also presented, which can be used to simplify the design of conical combiners and reduce the manufacturing effort. Two combiners are designed, one with a single-section and one with a multi-section transition, and output port reflection coefficients of -23 dB and -17 dB over bandwidths of 20 % and 43 % around 10 GHz are measured, respectively. This dissertation additionally presents a method that can be used in general to improve the input port isolation of N-way power combiners without affecting their reciprocity. A simple S-parameter proof is presented, followed by a derivation of equations that can be used to estimate the worst-case performance. Some design examples are presented, showing that terminations can be used for isolation loads. A prototype based on microstrip transmission lines is manufactured and a much improved input port reflection and isolation performance of -15 dB and 20 dB is measured, respectively, compared to a simulated input port reflection coefficient of -2:5 dB and isolation of 2:5 dB before the method was applied. ii
AFRIKAANSE OPSOMMING: Hierdie proefskrif stel 'n stroombaangebaseerde ontwerpsmetode voor wat lei tot voordele in terme van die fisiese grootte, vervaardigbaarheid, en vryheid in die ontwerp van koniese lyn kombineerders. 'n Ekwivalente stroombaanmodel vir die voerpoorte word onttrek, asook empiriese vergelykings wat gebruik kan word om die stroombaanelement waardes vanaf die afmetings van die kombineerder te bepaal. Dit laat die ontwerper toe om verskeie afmetings van die kombineerder te optimeer teen 'n beduidende laer koste in vergelyking met volgolf simulasies. 'n Ontwerpsprosedure word voorgestel en gebruik om 'n koniese kombineerder te ontwerp en 'n weerkaatskoëffisient van beter as -18 dB met 'n bandwydte van 46 % om 10 GHz word gemeet. Die prototipe is aansienlik kleiner as vorige ontwerpe, maar toon soortgelyke werkverrigting. Ontwerpsprosedures vir enkel en veelvoudige deel koniese na koaksiale lyn oorgange word ook voorgestel, wat gebruik kan word om die ontwerp en vervaardiging van koniese kombineerders te vereenvoudig. Twee kombineerders word ontwerp, een met 'n enkel deel oorgang en een met veelvoudige dele, en onderskeidelike uittree weerkaatskoëffisiente van -23 dB en -17 dB oor bandwydtes van 20 % en 43 % word gemeet. Hierdie proefskrif stel ook 'n metode voor wat gebruik kan word om die intree poort isolasie van N-rigting kombineerders in die algemeen te verbeter, sonder om die wederkerigheid daarvan te beïnvloed. 'n Bewys van die metode word gelewer, gevolg deur 'n afleiding van vergelykings wat gebruik kan word om die slegste-geval werkverrigting af te skat. Verskillende voorbeelde van kombineerders word getoon waarop die metode toegepas is, en wys dat terminasies gebruik kan word vir die isolasie laste. 'n Prototipe gebaseer op mikrostrook transmissielyne word vervaardig en 'n verbeterde intreepoort weerkaatskoëffisient en isolasie van onderskeidelik -15 dB en 20 dB word gemeet, in vergelyking met 'n weerkaatskoëffisient van -2:5 dB en isolasie van 2:5 dB voordat die metode toegepas is.
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Katakam, Sri. "Design of Multi Band Microwave Devices Using Coupled Line Transmission Lines." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc801903/.
Full textAbstract:
Multi band technology helps in getting multiple operating frequencies using a single microwave device. This thesis presents the design of dual and tri band microwave devices using coupled transmission line structures. Chapter 2 presents the design of a novel dual band transmission line structure using coupled lines. In chapter 3, Design of a dual band branch line coupler and a dual band Wilkinson power divider are proposed using the novel dual band transmission line structure presented in the previous chapter. In chapter 4, Design of a tri band transmission line structure by extending the dual band structure is presented. The Conclusion and future work are presented in chapter 5.
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Ristanovic, Dragan. "New methodology for transmission line relay testing and evaluation using advanced tools." Texas A&M University, 2003. http://hdl.handle.net/1969.1/355.
Full textAbstract:
Protective relays are important parts of the power system. The protection guards valuable equipment, and protective relays play a vital role in performing the task. The relay detects fault conditions within an assigned area, opens and closes output contacts to cause the operation of other devices under its control. The relay acts to operate the appropriate circuit breakers to prevent damage to personnel and property. To ensure consistent reliability and proper operation, protective relay equipment must be evaluated and tested.
The importance of the relay evaluation issue is linked to capability to test the relays and relaying systems using very accurate waveform representation of a fault event. The purpose of testing protective relays is to ensure correct operation of the relay for all possible power system conditions and disturbances. To fulfill this purpose, relay testing in varying network configurations and with different fault types is required. There are a variety of options that have different performance potentials and implementation constraints. Use of digital simulators to test protective relays has proven to be an invaluable mean to evaluate relay performance under realistic conditions.
This thesis describes a new methodology that attempts to improve the existing practices in testing relays by using advanced digital simulator hardware, different software packages for network modeling, and new software tools for generating and replaying test waveforms.
Various types of microprocessor relays are tested and evaluated through the set of scenarios. New methodology that combines different software packages to facilitate particular testing objectives is applied.
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Kiani, Mehdi. "Wireless power and data transmission to high-performance implantable medical devices." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53396.
Full textAbstract:
Novel techniques for high-performance wireless power transmission and data interfacing with implantable medical devices (IMDs) were proposed. Several system- and circuit-level techniques were developed towards the design of a novel wireless data and power transmission link for a multi-channel inductively-powered wireless implantable neural-recording and stimulation system. Such wireless data and power transmission techniques have promising prospects for use in IMDs such as biosensors and neural recording/stimulation devices, neural interfacing experiments in enriched environments, radio-frequency identification (RFID), smartcards, near-field communication (NFC), wireless sensors, and charging mobile devices and electric vehicles. The contributions in wireless power transfer are the development of an RFID-based closed-loop power transmission system, a high-performance 3-coil link with optimal design procedure, circuit-based theoretical foundation for magnetic-resonance-based power transmission using multiple coils, a figure-of-merit for designing high-performance inductive links, a low-power and adaptive power management and data transceiver ASIC to be used as a general-purpose power module for wireless electrophysiology experiments, and a Q-modulated inductive link for automatic load matching. In wireless data transfer, the contributions are the development of a new modulation technique called pulse-delay modulation for low-power and wideband near-field data communication and a pulse-width-modulation impulse-radio ultra-wideband transceiver for low-power and wideband far-field data transmission.
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Khomejani, Shabnam. "Performance enhancement of cognitive radio networks via multi-power level transmission." Thesis, King's College London (University of London), 2017. https://kclpure.kcl.ac.uk/portal/en/theses/performance-enhancement-of-cognitive-radio-networks-via-multipower-level-transmission(0f0a8ae7-cdab-48ba-b741-e5bd720effa8).html.
Full textAbstract:
The ubiquitous trend to the “next generation communication” is a symbol of the communication arena’s need for independence, efficiency and flexibility. Cognitive radio was introduced in the late 1990s as a concept to improve efficiency of spectrum use. Cognitive users would sense spectral holes and exploit unused spectrum. The original strategy suggested that spectrum being employed by licensed cognitive users should be strictly avoided in order to ensure no interference to the licensed users. However, this strict “white space” approach is also inherently spectrally inefficient. This Ph.D. thesis focuses its contributions to researching into technologies and solutions intended for cognitive radio networks that may lead to improvements in the coming wireless communication generations. Due to different technical challenges for spectrum sensing, power allocation and security in the physical layer, the contribution of this thesis is the proposition of a realistic scenario for cognitive radio systems. In this thesis, we suggest several strategies that offer limited interference to primary users while significantly improving the throughput of cognitive users. A novel cognitive radio scheme is proposed which exhibits improved achievable throughput levels and spectrum sensing capabilities compared to the conventional opportunistic spectrum access cognitive radio networks studied so far. The proposed cognitive radio strategy can overcome the sensing throughput trade-off problem in the opportunistic spectrum access cognitive radio systems. In addition, it also provide its cognitive users with increased levels of average achievable throughput.
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De, Villiers Wernich. "Prediction and measurement of power line carrier signal attenuation and fluctuation." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52410.
Full textAbstract:
Thesis (MScEng)--University of Stellenbosch, 2001,ENGLISH ABSTRACT: A frequency domain Power Line Carrier (PLC) simulation program, with the ability to simulate signal attenuation including the coupling equipment, was developed. This simulation program was put to the test against the independent program of Professor L.M. Wedepohl and against practical field measurements. The predictions of the two programs were in precise agreement for a wide range of input parameters. Results from the field tests and predictions also showed close agreement. Further investigations, applying the simulation program, explained how ground conductors and soil resistivity influences PLC signal propagation. An experiment, which was developed to monitor PLC signal attenuation, was installed on the PLC system between Koeberg power station and Acacia substation, both near Cape Town. Data logged continuously over 28 days, indicated measurable and deterministic PLC signal attenuation variations with typical time constants of a few hours. Simulations of the PLC system indicated that the signal amplitude variations were influenced by changes in the height above the ground plane of the phase conductor. This significant finding creates the possibility to obtain real time knowledge of the sag of an Over Head Transmission Line (OHTL) by exploiting an operational PLC system. The knowledge about real time sag can be used in economical dynamic ampacity control systems. The practical and financial benefits to the electricity supply and distribution industry can be significant.
AFRIKAANSE OPSOMMING: 'n Frekwensie gebied "Power Line Carrier" (PLC) simulasie program wat die sein verswakking en die koppeling verliese kan naboots, is ontwikkel. Die program is getoets teen die onafhanklike program van Professor L.M. Wedepohl asook praktiese metings in die veld. Die vooruitskatings van beide programme is presies die selfde vir 'n wye reeks van parameters. Metings en nabootsings het ook noue ooreenstemming getoon. Verdere ondersoek, m. b. v. die program, is gedoen ten einde te verduidelik hoe grond-geleiers en grond weerstand die PLC sein se voortplanting beïnvloed. 'n Eksperiment om die PLC sein se verswakking mee te monitor is ontwerp. Die eksperiment was geïnstalleer in die PLC stelsel tussen Koeberg kernkragstasie en Acacia substasie, naby Kaapstad. Die eksperiment was vir 28 dae geaktiveer en die data wat die eksperiment opgelewer het toon meetbare PLC sein verswakking met tyd konstantes van 'n paar uur. Verdere nabootsings het gewys dat die veranderende verswakking in die PLC seinsterkte toegeskryf kan word aan die wisseling in hoogte van die fase geleiers bo die grondvlak. Hierdie bevinding is van besondere belang aangesien dit die moontlikheid oopmaak om die gemiddelde sak van kraglyne in reële tyd en onder bedryfs toestande te kan meet. Die informasie van die reële sak van kraglyne kan gebruik word in effektiewe stroomdrae-vermoë beheer stelsels. Die praktiese en finansiële voordele wat krag voorsieners en verspreiders hieruit kan put kan aansienlik wees.
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MacNeill, Aaron. "Submarine Power Cable Transmission Line Parameters and Performance." 2012. http://hdl.handle.net/10222/15470.
Full textAbstract:
Submarine power production installations use the power of the ocean to generate
renewable energy for the population to use. To bring this electricity back to land, use of
electrical cables is required. The choice of cable will affect both the quality of received
power and the security of the transmission line. To find the inductance and capacitance of these submarine transmission lines, a study of the electric and magnetic fields that are produced due to the power flow on these cables must be performed. The armor that is used to protect the cable from underwater hazards is significant in determining the cable losses and finding the equivalent inductance and capacitance. Finding the inductance and capacitance of the submarine cable will allow for the determination of the two port parameters of the cable. These parameters will allow for the analysis of the transient and steady state performance of the cable.
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Goyal, Anuj. "Performance Enhancement of Power Line Communication Using OFDM and CDMA." Thesis, 2013. http://ethesis.nitrkl.ac.in/5411/1/211EC3308.pdf.
Full textAbstract:
Power line communication has been emanated as one of the most enduring means of communication for smart grid applications especially while considering the biggest advantage i.e. an already established infrastructure, therefore sending out the control information over the same network will add only a little cost and hence opens the door for a plethora of applications. The communication over Power Line is not so new when we are concerned about generation, transmission or deliverance of power but here our main concern is control and management of power rather than transmission or deliverance of power and this purpose can only be accomplished if we are utilizing the available resources in an efficient manner which in turn is dependent on the fast and effective transmission of data or control information over these channels. To ensure the fulfilment of these requisites there is a requirement to analyse the basic topological connections and the circuit modelling and thus determined the various control and traffic problems associated with the transmission of this information which usually varies according to applications. Therefore OFDM (BPSK, QPSK, and QAM) has been utilized for the purpose of analysis of the channel performance while ensuring the speed and robustness of the channel to be the main criteria for any kind of services or applications .Moreover there usually arises a problem of power failure and reliable communication over remote locations and therefore the solution for it is an interfacing between wired and wireless communication technologies and hence in the thesis work, a comparison of the bit error probability had been shown between the performance of the channel while using OFDM and CDMA and this comparison provides an solution to choose the technology according to the requirement of application .
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Matshidza, Rhulani Daphney. "Improved transmission line protection performance concerning high resistance faults." Thesis, 2006. http://hdl.handle.net/10413/2211.
Full textAbstract:
ESKOM has relied primarily on impedance-based measurement protection relays for the protection of transmission lines. One of the main disadvantages of distance relays is the limited fault resistance measurement capability. High-resistance faults are characterised by low fault currents, therefore the impedance calculated would be much bigger and so the fault will appear to be beyond the protected line. The main aim of the study is to gain clear understanding of the capability of the existing relays used in Eskom Transmission network, to be able to give recommendations on the refinements to the transmission line protection philosophy required to improve future protection performance. Omicron relay tests, showed that the dynamic characteristics of the three selected relays which were tested covers more fault resistance than that of the normal static impedance and also that the effect of DC offset is negligible with regards to fault resistance measurement capability. Normally the relays have built in algorithms which are able to filter nuisance signals. Theoretical case study that compared the most used relays in Eskom Transmission was done and the results are documented. Settings recommendations to improve fault resistance coverage were deduced from the above study. Fault investigation by using digital simulations (Matlab simulations) has proven the lack of capability to operate for some impedance relays in some fault conditions, as the fault resistance sometimes moves fault impedance beyond relay characteristic even when actual . polarization of the relay is considered. Analysis of the protection performance in transmission proved that high resistance faults accounts for at least half of protection equipment performance index (PEPI) incidents. Finally the author made recommendations to improve the protection performance concerning high resistance faults.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2006.
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Jena, Smrutisinha. "Performance Analysis of Transmission Line Using Upfc With Pi and Fuzzy Controller." Thesis, 2016. http://ethesis.nitrkl.ac.in/8083/1/2016-Mtech--214EE4543-Performance.pdf.
Full textAbstract:
High quality power and high efficient power is an apprehension for now days due to advancement in electrical technology. Today’s power systems are highly composite and require suitable design when new effective and consistent devices are to be introduced in the liberalized electric power industry. This is done in order to flexibly control the power flow. In the early 1980s, the Electric Power Research Institute (EPRI) framed a new strategy in order to resolve the difficult of designing, adjusting and functioning the power systems: the projected concept came to be known as Flexible AC Transmission Systems (FACTS). It is reckoned conceptually as a target for the long term development in order to offer new opportunities for controlling the power in addition to enhancing the capacity of the present as well as new lines in the coming decades. Its main objectives are to raise power transmission capability, voltage control, voltage stability enrichment and power system stability improvement.
There are several FACTS controllers. Among them the UPFC is the most adaptable and proficient device which was introduced in 1991. In UPFC, the transmitted power can be controlled by changing three parameters namely the magnitude of the transmission voltage, the impedance and the phase angle. The Unified Power Flow Controller (UPFC) is the most prominent member of the FACTS family which has the capability to control parameters such as voltage, impedance and phase angle. By the use of UPFC a superior power flow control over the existing power line is not only possible but also it will work nearer to its thermal stability limit making the system more efficient and reliable.
FACTS devices controls the power flow in a systematic manner by which not only the power flow is controlled but also the stability of the system is always maintained in a space region. The control mechanism incorporated with the UPFC has an edged control over the power flow and the system stability. The performance is varied for different control mechanism used for the control of UPFC. The performance of each controller must be properly studied before implementing to the power system. The two controllers are PI and Fuzzy. On comparing we can say that Fuzzy Logic Controller based UPFC gives better voltage sag compensation than PI Controller based UPFC.
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De-MingLin and 林德銘. "Performance Analysis and Strategy Evaluations of Line Arresters for Lightning Restriction on Electric Power Transmission Lines." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/04632345744732021207.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
98
This thesis is aimed to investigate the lightning restriction performance of line arresters installed in overhead transmission lines, through which the results are gained as a useful reference to decrease the flashover accidents and increase the operation reliability. In the thesis, the data of lightning statistics is first collected such that the lightning model related with transmission lines can be well constructed. Then, several placement strategies of line arresters are analyzed under different lightning locations and lightning energy. Meanwhile, the computation of failure rate of line arrester under various footing resistance is also well performed, thus anticipating the optimization of line arrester placement strategy can be better consolidated while the lightning restriction quality on overhead transmission lines can be highly improved.
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LIN, SHYH-RU, and 林世孺. "Multi-objective Genetic Algorithm Solution to the Optimum Maintenance Performance Problem of Power Transmission Line." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/27943052852100329766.
Full textAbstract:
碩士中華大學
資訊管理學系碩士在職專班
101
The electrical power system is critical in modern economic activity, it will make seriously economic damage if power interrupted in accident. There are lots of ways to keep system running continuously to avoid such situation and lower property damage from the accident. The Power transmission line (PTL) is an important section of the whole network. How to keep it stable working and do not breakdown is most important issue in the power system. Normally, the foreman choice to maintain area monthly for network is arbitrary. They never care of cost and facility actual status whether requirement needed or not. In this paper, we will try to set up an algorithm that may find out what and where is the area that system maintains needed most urgently and cost efficiently, with four indexes: “the condition of PTL”, “the reliability of the PTL”, “interval of maintenance”, “minimize distance”, this study will indicate a Multi-objective decision-making method used for the maintenance of PTL to achieve the above four indicators. With these concepts of reliability, Hungarian method, genetic algorithm, etc. we’ll propose a Multi-objective decision-making method used for the maintenance of PTL .The four indicators parameters, can be adjusted by different target weights.Finally, relation to information technology of genetic algorithms,With the model of transmission maintenance implementation,We could solve PTL combinations results most appropriate. Compare algorithm with actually working record since January 2011 and expiring in December 2012, the algorithm is applied to 65 lines and two years examination.This study results with the findings that could satisfied our desirable purpose: minimize distance of Maintenance, while its reliability of persistent working could also be ensured and finaly reduce maintenance costs.
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Yuan, Lin Ju, and 林車遠. "A Study on the Operation Performance for the Transmission Line System of Taichung Power Supply Branch of Taiwan Power Company." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/03452701202463861132.
Full textAbstract:
碩士臺中健康暨管理學院
經營管理研究所
93
A Study on the Operation Performance for the Transmission Line System of Taichung Power Supply Branch of Taiwan Power Company Abstract Electricity is the mother of industry, the island wide blackouts caused by July twenty-nine Event and September Twenty-first Earthquake in 1999 brings about great economic damages. This thesis aims to explore how to reach the highest managing achievement. The research method included questionnaire and specialist interview survey. A questionnaire was distributed to all interior employees of the transmission line system department in Tai-Chung branch of Taiwan Power Company, and exterior employees of the line system department in Tai-Chung, Chang-Hua, Nan-Tou district offices. In total 400 interior questionnaires, the 332 returned questionnaire, the valid returning rate numbered 83%. This research is to gather statistics regarding the managing achievement of the special maintaining personnel of transmission line system. The data was gathering by questionnaires of the balance scored cards and then analyzed with the SPSS program to discover the characteristics of managing achievement from sides of financial, customers, inner procedures, learning & grow up, executives and managing strategies. The result revealed that: 1.Evolving from one to ten power companies（including 9 IPP power plants）, the composition is getting fiercely. Only can the strong teamwork develop great managing achievements. 2. The research was done by the balance scored cards from four sides of financial, customers, inner procedures, learning and grow up to discover the combined mechanism differences revealed that the four sides were distributed uniform, the company well good and the left rates was low. Distinguish from stable supply power and do well service to get profit; use well project can change supply power system weakness , shaau the expenditures and make provisions before troubles occur. The most important is to train employees and create a wisdom property right. 3. This research aims to explore the managing achievement of special environment and based on various interior operation principles, maintain the equipment and let supply power normal, and what’s more keep techniques, make natural disaster plan, do the well training, let employee has more loyalty, and then the company well get the goal
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Maturu, Suresh. "Performance Evaluation Of Distance Relays For FACTS Compensated Transmission Lines." Thesis, 2011. https://etd.iisc.ac.in/handle/2005/2084.
Full textAbstract:
With limited enhancement or expansion of the transmission infrastructure, the contemporary power systems are operating under more stressed conditions. It becomes important to fully utilize the existing transmission system to supply load demand as much as possible, thus eliminating or reducing the need for new transmission investment.
Flexible AC Transmission System (FACTS) technology provides an alternative to fully utilize the existing transmission lines as well as new and upgraded lines, by controlling power and also enhancing the power transfer capability of transmission lines. However, the implementation of FACTS controllers in the transmission system has introduced new power system dynamics that must be addressed in the area of power system protection, such as rapid changes in line impedance, power angle, line currents, transients introduced by the occurrence of fault and associated control action of the FACTS controller. Therefore, the performance of the protection system must be carefully analyzed in the presence of FACTS controllers.
The thesis aims at evaluating the performance of distance relays when different types of FACTS controllers, in particular Voltage Source Converter (VSC) based FACTS controllers, are incorporated at the midpoint of the transmission system to achieve voltage profile improvement and power transfer capability. The detailed models of these controllers and their control strategies are described. The presence of FACTS controllers in the loop affects both steady state and transient components of voltage and current signals. The rapid response of FACTS controllers to different power system configurations significantly affects the apparent impedance seen by distance relays. The apparent impedance seen by distance relays would be different from that of the system without FACTS controller. Due to this, the distance relay may malfunction, resulting in unreliable operation of the power system during faults. Furthermore, the effect of FACTS controllers on distance relay operation depends on the type of FACTS controller used, the application for which it has been installed and its location in the power system. The distance relay is evaluated for different loading conditions and for various fault conditions. Simulation studies are carried out using PSCAD/EMTDC based transient simulation package.
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Maturu, Suresh. "Performance Evaluation Of Distance Relays For FACTS Compensated Transmission Lines." Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/2084.
Full textAbstract:
With limited enhancement or expansion of the transmission infrastructure, the contemporary power systems are operating under more stressed conditions. It becomes important to fully utilize the existing transmission system to supply load demand as much as possible, thus eliminating or reducing the need for new transmission investment.
Flexible AC Transmission System (FACTS) technology provides an alternative to fully utilize the existing transmission lines as well as new and upgraded lines, by controlling power and also enhancing the power transfer capability of transmission lines. However, the implementation of FACTS controllers in the transmission system has introduced new power system dynamics that must be addressed in the area of power system protection, such as rapid changes in line impedance, power angle, line currents, transients introduced by the occurrence of fault and associated control action of the FACTS controller. Therefore, the performance of the protection system must be carefully analyzed in the presence of FACTS controllers.
The thesis aims at evaluating the performance of distance relays when different types of FACTS controllers, in particular Voltage Source Converter (VSC) based FACTS controllers, are incorporated at the midpoint of the transmission system to achieve voltage profile improvement and power transfer capability. The detailed models of these controllers and their control strategies are described. The presence of FACTS controllers in the loop affects both steady state and transient components of voltage and current signals. The rapid response of FACTS controllers to different power system configurations significantly affects the apparent impedance seen by distance relays. The apparent impedance seen by distance relays would be different from that of the system without FACTS controller. Due to this, the distance relay may malfunction, resulting in unreliable operation of the power system during faults. Furthermore, the effect of FACTS controllers on distance relay operation depends on the type of FACTS controller used, the application for which it has been installed and its location in the power system. The distance relay is evaluated for different loading conditions and for various fault conditions. Simulation studies are carried out using PSCAD/EMTDC based transient simulation package.
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Yen-Ting, Lo, and 駱彥廷. "A Study on the Relationships between Job Satisfaction and Job Performance for Dispatched worker.—An Example of Department of Transmission Line and Substation Projects, Taiwan Power Company." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/88113093340615191882.
Full textAbstract:
碩士國立中山大學
企業管理學系研究所
94
In recent years, more and more companies and enterprises started using dispatched worker. This new trend of “hiring, not employing” brought profound impact and challenges to the existing structure of labor-employer relations, as well as human resource management. Even in the government department. The main purpose of this study was to investigate the relationships between job satisfaction and job performance for government dispatched workers, taking Department of Transmission Line and Substation Projects（DTSP） as an example. There were 145 effectual samples in this study. Questionnaire survey was the main research method of this study. The research instrument included job satisfaction scale and job performance scale. The data were analyzed through Frequency Distribution, T-test, one-way ANOVA and Person Correlation Analysis. After this study analysis, the conclusion is made as follows: 1. The degree of DTSP dispatched workers’ job satisfaction (average score is 3.42, standard deviation (SD) is 0.52) is not so high as expected. The degree of DTSP dispatched workers’ job performance (average score is 3.71, standard deviation (SD) is 0.53) is belonged to normal level. 2. The dispatched workers’ job satisfaction and job performance are related significantly and positively. 3. For dispatched workers’ personal background, there are two variables which have influence to the job satisfaction, belonged department and belonged region . 4. For dispatched workers’ personal background, there are two variables which have influence to the job perfomance, belonged department and belonged region
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Strelec, Gavin Jason. "Comparison of the lightning performance between the poles of the Cahora-Bassa ±533 kV HVDC lines." Thesis, 2016. http://hdl.handle.net/10539/21066.
Full textAbstract:
This work contributes toward research in the field of lightning performance of High Voltage Direct Current (HVDC) transmission lines, focusing on the impact of the line polarity on the incidence of line faults. Although there has been some recent research into the influence of polarity, there appears to be no confirmed effect that might influence the design of new lines. The research presents an investigation into the lightning performance of the two poles of the Cahora-Bassa HVDC transmission line. In order to compare the performance of the two polarities, the average lightning exposure over an 8-year period was confirmed to be very similar for both lines. Lightning stroke data from the South African Lightning Detection Network was correlated with fault times from the transmission-line protection scheme. The classification of the lightning related faults was used to determine the relative performance of the two poles, particularly in relation to polarity, and to infer if there was any influence of polarity on the lightning attachment process. This investigation for the Cahora-Bassa scheme shows that twenty-three out of twenty-five lightning related faults occurred on the positive pole. The results concur with performance experience on several HVDC lines from China and Canada, which indicate that lightning related faults favour the positive pole by a ratio of between 8:1 and 10:1. This represents a valuable contribution, which substantiates that HVDC line polarity has an influence on the lightning attachment process, and indicates that there is a need to re-examine the lightning shielding design for HVDC transmission lines.GS2016
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Bortnik, Jacob. "Transmission line compaction using high phase order transmission." Thesis, 2016. http://hdl.handle.net/10539/20879.
Full textAbstract:
A dissertation submitted to the Faculty of Engineering,
University of the Witwatersrand, Johannesburg, in
fulfilment of the requirements for the degree of Master
of Science in Engineering
Degree awarded with distinction on 8 December I998
Johannesburg, 1998This report discusses high phase order (HPO) technology, i.e. the use of more than the conventional 3 phases for transmission of electric power, its use in the compaction of lines, and power density maximization over existing servitudes. It is structured in four parts. The first part introduces the concepts, establishes the need, and lists the advantages ofHPO. The second part deals with the technology itself and shows that it is possible to analyze HPO systems using symmetrical component analysis, lists common transformer configurations, covers protection, and so on. The third part analyses 5 case studies, the first 3 being analytical, and the last 2 being the first experimental test line, and the world's :first utility application ofHPO lines. The fmal section is a South African case study and compares an HPO line to an existing 400 kV 3-phase line and shows that the former is 87.5% more expensive to implement than the latter. Comparing the 3-phase and 6-phase lines on a more even basis, yielded a breakeven distance of225.86 km, above which the 6-phase option becomes more economical. These results are then explained and discussed in the conclusions section.
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Janse, van Rensburg P. A. "Effective coupling for power-line communications." Thesis, 2009. http://hdl.handle.net/10210/2442.
Full textAbstract:
D.Ing.The technique of using a live power cable to simultaneously transport a communication signal, has been practiced since the early 1900’s. In most cases, power-line communications has been implemented as a retrofit technology, with its main benefit being the utilization of a ‘free’ existing network. This driving force of power-line communications is typical for high-, medium-, and low-voltage distribution networks, as well as intra-building networks currently targeted for home automation and home networking. Researchers have thus focused on the optimum use of these existing power-line channels, often accepting the inherent drawbacks of this hostile communication channel. Apart from unpredictable noise sources, two main disadvantages of the low-voltage powerline network as a communication channel, are i) the unknown power cable characteristics and topology and ii) time-dependent fluctuation of the power-line impedance level as loads are unpredictable switched into, and out of the network. These two factors have obscured the requirements for proper coupling and impedance adaptation to the degree that most researchers and manufacturers have merely accepted this typical ≈ 20-dB coupling loss as one of the inherited disadvantages of the power-line channel. Most researchers and manufacturers have thus defaulted to a guessed power-line impedance level, and have used one fixed coupler winding ratio under all circumstances, regardless of power-line conditions. This study has shown that proper coupling and impedance adaptation can yield significant transmission gains even with limited (qualitative) knowledge of a power-line channel and its topology. After formulating design steps for an impedance-adapting coupler that facilitates bidirectional transmission, the impact of the fluctuating power-line impedance on coupler bandwidth was investigated. Next, impedance adaptation strategies were considered and the tradeoff between series cable requirements and parallel load requirements was explored. A model of sufficient simplicity was developed to facilitate qualitative description and classification of power outlets – functioning as communication nodes. Very interesting simulation results were obtained and these were verified using a laboratory setup of characterized power cables and calibrated loads. Next, these simulation results were employed to improve power-line transmission over a live, uncharacterized 220-V residential network by means of i) classifying typical residential rooms qualitatively in order to choose proper coupler winding ratios and ii) using an innovative dual coupler for dedicated on-off switching with harsh loads, thereby mitigating the fluctuating impact of said loads on low-voltage power-line communications.
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Yi-Shin, Wu, and 吳宜欣. "A Study on Transmission Properties of Power Line." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/10733013922542234833.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
92
The transmission properties of the power-line communications are studied to evaluate the possible applications of the power-line communications for Taiwan Power Company. The related regulations and current developments of the power-line communications are collected for references. Also, the transmission properties of the Taipower distribution systems are measured, and signal attenuation and impedance matching are evaluated. The transmission models of the power-line carriers are applied in order to analyze the signal propagation. Besides, measurements of the electromagnetic interferences due to the power-line carriers are performed and the noises possibly interfering the power-line communications are studied. Results obtained from this project may be applied in planning and deploying the power-line communications systems for Taiwan Power Company.
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陳衍璋. "Signal transmission for vehicles using power line communications." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/00653043929258501825.
Full textAbstract:
碩士國立交通大學
電控工程研究所
100
We proposed a PLC system for transmitting signals in battery electrical vehicle via power line, and implemented it in an IC. The proposed system can support ten components. The tape-out IC have the following specification: The maximum data rate of the chip is 50 kbps. The die area is 3.74 mm2 and the technology is TSMC0.18 um. The power consumption of the chip is 45 mW.
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Lin, Chyi-Taur, and 林祺濤. "A Study on Data transmission by Power Line." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/07881770229968358481.
Full textAbstract:
碩士國立高雄第一科技大學
電腦與通訊工程所
91
A Study on Data Transmission by Power Line Student：Chyi-Taur Lin Advisors：Dr. Wei-Chih Hsu Department of Computer and Communication Engineering National Kaohsiung First University of Science and Technology 英文摘要 ABSTRACT This paper presents a characteristical measurement of power line to probe the possibility as a kind of communicational medium. The electric potential attenuation of power line against frequency has been measured by means of signal generator, frequency counter, and ocsilloscope. We wrote a program to measure the byte-loss rates of the server-to-client data transmission on the power lines with different lengths. Besides,we also investigated the influences of no-fuse breaker and the power with different phases on data transmission. In application, we constructed a PC-based power line communicator to control a programmable message sign. The alphanumerical characters were sent from the computer to the message sign for display. We also programmed a timing corrector to actively or passively transmit the date and the time of the server computer to the client computer for alignment. The experiments show that power line is capable of data transmission. The experimental results reveal that the electrical attenuation of power line varies with frequency. The transmission distance and the numbers of connected appliances also affect the loss rate of data transmission.
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Chen, Tai-Chen, and 陳泰蓁. "Performance Optimization Under the Transmission Line Model." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/82510908347426425020.
Full textAbstract:
碩士國立交通大學
資訊科學系
89
Transmission line effects are very important for the timing estimation and optimization in high-performance circuits. Most previous works on transmission lines are based on relatively complicated models, resulting in higher time complexity. We present a simple, yet accurate formula for the delay computation under the lossless and lossy transmission line models. Extensive simulations with SPICE show that the formula has high fidelity, with an average error rate of within 6.85% (1.50%) for a lossy (lossless) transmission line. Based on this formula, we show the property that the minimum delay for a lossy transmission line with reflections occurs when the number of round trips equals one. Besides, we show that the delay (with the consideration of fringing capacitance) of a circuit path is a posynomial function (i.e., convex function) in wire and buffer sizes, implying that a local optimum is equal to the global optimum. Thus we can apply any efficient search algorithm, such as the well-known gradient search procedure, to compute the optimal wire and buffer sizes for timing optimization for a circuit path. Experimental results show that simultaneous wire and buffer sizing is very effective in minimizing the delay of circuit paths under the transmission line model.