Dissertations / Theses on the topic 'Electric power transmission network'
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Shaaban, Mohamed Mohamed Abdel Moneim. "Calculation of available transfer capability of transmission networks including static and dynamic security." Thesis, Click to view the E-thesis via HKUTO, 2002. http://sunzi.lib.hku.hk/hkuto/record/B42576817.
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Grosse, Philippe. "Application of knowledge engineering techniques for managing operational expertise of transmission network operator." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249049.
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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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Radibratovic, Branislav. "Reactive optimization of transmission and distribution networks." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28264.
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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.Committee Chair: Begovic, Miroslav; Committee Member: Divan, Deepakraj; Committee Member: Dorsey, John; Committee Member: Ferri, Bonnie; Committee Member: Lambert, Frank.
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Das, Debrup. "Dynamic control of grid power flow using controllable network transformers." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43739.
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The objective of the research is to develop a cost-effective, dynamic grid controller called the controllable network transformer (CNT) that can be implemented by augmenting existing load tap changing (LTC) transformers with an AC-AC converter. The concept is based on using a fractionally rated direct AC-AC converter to control the power through an existing passive LTC. By using a modulation strategy based on virtual quadrature sources (VQS), it is possible to control both the magnitude and the phase angle of the output voltage of the CNT without having any inter-phase connections. The CNT architecture has many advantages over existing power flow controllers, like absence of low frequency storage, fractional converter rating, retro-fitting existing assets and independent per-phase operation making it potentially attractive for utility applications.
The independent control of the magnitude and the phase angle of the output voltage allow independent real and reactive power flow control through the CNT-controlled line. In a meshed network with asymmetric network stresses this functionality can be used to redirect power from critically loaded assets to other relatively under-utilized parallel paths. The power flow controllability of CNT can thus be used to lower the overall cost of generation of power. The solid state switches in the CNT with fast response capability enable incorporation of various additional critical functionalities like grid fault ride through, bypassing internal faults and dynamic damping. This bouquet of features makes the CNT useful under both steady state and transient conditions without compromising the grid reliability.
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Jayachandran, Krishna K. "STBC-encoded cooperative asynchronous transmissions for transmission energy efficiency." Diss., Online access via UMI:, 2005.
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Jones, Peter Gibson. "Evaluation of Voltage Instability Countermeasures in Constrained Sub-transmission Power Networks." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/112.
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This paper investigates the various parameters that effect voltage stability in sub-transmission power networks. The paper first looks at contributions from equipment: generators, transmission lines, transformers, capacitors, SVCs and STATCOMs. The paper also looks at the effects of loads on voltage stability. Power flow solutions, PV and VQ curves are covered. The study models an existing voltage problem i.e., a long, radial, 115 kV sub-transmission network that serves a 65 MW load. The network model is simulated with the following voltage instability countermeasures: adding a capacitor, adding an SVC, adding a STATCOM, tying to a neighboring transmission system, adding generation and bringing in a new 230 kV source. Then, using the WECC heavy-winter 2012 power flow base case and Siemens PTI software, VQ and PV curves are created for each solution. Finally, the curves are analyzed to determine the best solution.
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Kim, Joong-Ho. "Modeling of package and board power distribution networks using transmission matrix and macro-modeling methods." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/13864.
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McIlwaine, Stephen Andrew. "Reduction of spinning reserve requirements on the Northern Ireland electrical power network." Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317130.
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Bauknecht, Dirk. "Transforming the Grid : electricity system governance and network integration of distributed generation." Thesis, University of Sussex, 2011. http://sro.sussex.ac.uk/id/eprint/7443/.
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The thesis analyses how the standard model of liberalised electricity markets that was developed to increase the efficiency of electricity supply can deal with new objectives. While the liberalisation literature argues that additional objectives can be incorporated in the market framework through price signals, a large body of literature based on evolutionary economics argues that innovation and systemic transformation require governance mechanisms that complement the price mechanism of the market to overcome the lock-in of the existing system and coordinate innovation processes. The thesis focuses on the integration of distributed generation (DG) into electricity networks. In the standard model the governance of networks is mainly based on incentive regulation by independent regulators. Thus, the main question is how DG can be integrated into this regime and whether and how it needs to evolve. The research question is broken down according to both different governance issues (connection, integration, innovation, transformation) and different governance levels on which they can be addressed. This is analysed from two angles: Firstly, there is a mainly theoretical discussion of network regulation. Various approaches to amending the standard model are discussed. Secondly, this is complemented by country case studies of the UK and Denmark. The conceptual analysis shows how incentive regulation can accommodate the efficient integration of DG as an additional objective. There is also scope for this model to incorporate governance mechanisms that are geared towards infrastructure transformation. The UK case study shows the practical implementation of this approach and corresponding difficulties. As for Denmark – a DG and network transformation pioneer – the standard model plays a marginal role and economic issues are mainly dealt with outside regulation. The same is true for mechanisms beyond economic incentives. The thesis shows the potential of the standard model to pursue new objectives as well as the need to broaden the scope beyond governance based on economic incentives.
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Kundy, Beda Jerome. "Probabilistic analytical methods for evaluating MV distribution networks including voltage regulating devices." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52414.
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Thesis (PhD)--Stellenbosch University, 2001.ENGLISH ABSTRACT: Accurate load models are required for the computation of load flows in MV distribution networks. Modem microprocessors in recent times enable researchers to sample and log domestic loads. The findings show that they are stochastic in nature and are best described by a beta probability distribution. . In rural areas two different load types may be present. Such loads are domestic and pump loads, the latter may be modelled as constant P - Q loads. An analytical tool for computing voltage regulation on MV distribution networks for rural areas feeding the mentioned loads is therefore required. The statistical evaluation of the consumer voltages requires a description of load currents at the time of the system maximum demand. To obtain overall consumer voltages at any specified risk for the two types of the loads, the principle of superposition is adopted. The present work deals with conventional 22kV three-phase distribution (te:. - te:.) connected networks as used by ESKOM, South Africa. As the result of the connected load, MV networks can experience poor voltage regulation. To solve the problem of voltage regulation, voltage regulators are employed. The voltage regulators considered are step-voltage regulators, capacitors and USE (Universal Semiconductor Electrification) devices. USE devices can compensate for the voltage drops of up to 35% along the MV distribution network, thus the criteria for the application of the USE devices is also investigated. The load currents are treated as signals when assessing the cost of distribution system over a period of time due to power losses. The individual load current signal is modelled by its mean and standard deviation. The analytical work for developing general expressions of the total real and total imaginary components of branch voltage drops and line power losses in single and three-phase networks without branches are presented. To deal with beta-distributed currents on MV distribution networks, new scaling factors are evaluated at each node. These new scaling factors are derived from the distribution transformer turns ratio and the deterministic component of the statistically distributed load currents treated as constant real power loads. In the case of an individual load current signal, the transformation ratio is evaluated from the distribution transformer turns ratio and the average value of the· signal treated as constant real power load. The evaluation of the consumer voltage percentile values can be accurately evaluated up to 35% voltage drop. This is possible by the application of the expanded Taylor series, using the first three terms. The coefficients of these three terms were obtained using a search engine imbedded in the probabilistic load flow. The general expressions for evaluating the overall consumer voltages due to statistical and non-statistical loads currents are also given. These non-statistical currents may be due to constant P - Q loads, line capacitance and the modeling of voltage regulators. The Newton-Raphson algorithm is applied to perform a deterministic load flow on singlephase networks. A backward and forward sweep algorithm is applied to perform a deterministic load flow on single and three-phase systems. A new procedure for modelling step-voltage regulators in three-phase (te:. - te:.) connected networks is outlined. Specifying a transformation ratio of 1.1 and 1.15 respectively, identifies the open-delta or closed-delta configuration for three-phase networks. The algorithms and the developed general expressions for single and three-phase networks without branches are presented in this work. A new algorithm is developed to enable the developed general expressions to be applied to practical MV distribution networks. The algorithms were tested for their accuracy by comparing the analytical results with Monte Carlo simulation and they compared well. An illustrative example to show the application of the present work on a practical MY distribution networks is presented. A criterion for the application of the USE devices is outlined. It is anticipated that, the work presented in this thesis will be invaluable to those involved in the design of MY distribution systems in developing countries.
AFRIKAANSE OPSOMMING: Akkurate lasrnodelle word benodig vir drywingsvloei analises in MV distribusiestelsels. As gevolg van nuwe digitale verwerkers is dit deesdae moontlik om huishoudelike laste te monitor. Die lasdata dui daarop dat laste stochasties is en kan met behulp van die Beta verdeling beskryf word. In landelike gebiede is daar twee tipes laste. Hulle is eendersyds huishoudelike laste en andersyds pomp-tipe laste wat as konstante P-Q laste beskou kan word. Dit is dus belangrik om toepaslike analitiese metodes te gebruik om die spanningsvalle by hierdie laste te bereken met inagname van die las-tipes. By die statistiese berekening van die verbruiker se spanning moet 'n statistiese model van die lasstroom verskaf word op die tydstip van maksimum aanvraag. Daarna moet die prinsiep van superposissie gebruik word om die spannings by verskeie nodes by 'n gespesifiseerde vertrouensinterval te bepaal. Hierdie proefskrif is gebaseer op konvensionele 22kV, drie fase distribusie (delta na delta) netwerke, soos deur Eskom, Suid Afrika gebruik. Hierdie stelsels ondervind dikwels nadelige spanningsvlakke en spanningsreëlaars word derhalwe aangewend. Hierdie reëlaars is gewoonlik van tap-tipe of daar kan ook gebruik gemaak word van kapasitore en ook elektroniese reëlaars soos die USE tipe toestelle. Laasgenoemde kan op LV vir spanningsvalle tot 35% kompenseer. In hierdie werk word die werkdrywing verliese in die geleiers bereken met behulp 'n seinmodel van die lasstrome. Die individuele lasstrome word by wyse van gemiddeldes en variasies beskryf. Om die algemene algoritmes vir die berekening van die reële en imaginêre spanningsvalle, asook die verliese in enkelfase en driefase stelsels daar te stel word aanvanklik gebruik gemaak van stelsels sonder vertakkings. Om die statistiese lasbeskrywing op die laagspanningskant na die MV vlak oor te dra word van nuwe skaalfaktore gebruik gemaak. Hierdie faktore word bereken op die basis van die transformator se verhouding en die deterministiese komponent van die statistiese verspreide lasstrome, as konstante reële drywingslaste beskou. Met die ontwikkelde metode kan die verbruiker se spanning by 'n gegewe vertrouensinterval akkuraat bereken word vir spanningsvalle tot 35%. Dit word moontlik gemaak deur die Taylor-reeks tot drie terme toe te pas. Daar moet egter gebruik gemaak word van toepaslike koëffisiënte wat bepaal word deur 'n geprogrammeerde soektog. 'n Algemene stel vergelykings om die spanning by enige verbruiker te bereken, ongeag die topologie van die netwerk, word ook gegee. Die Newton-Raphson metode word aangewend om die deterministiese drywingsvloei op enkelfase stelsels te bereken. A truwaartse-voorwaartse metode is gebruik om die drywingsvloei te bepaal vir driefase stelsels. 'n Nuwe prosedure is ontwikkel vir die modellering van die spanningsreëlaars in driefase, delta-delta netwerke. Deur gebruik te maak van 'n transformatorverhouding van 1.1 of 1.15 kan die oop-delta of toe-delta netwerke voorgestel word. 'n Nuwe algoritme is ontwikkelom multi-vertakkings in 'n netwerk te hanteer. Al die prosedures is deeglik met behulp van Monte Carlo simulasies getoets en die resultate is heel bevredigend. Om die metodes te illustreer word 'n gevallestudie ingesluit waar die metodes gebruik word om 'n netwerk te evalueer met en sonder die sogenaamde USE toestelle. Kriteria vir die aanwending van hierdie toerusting word voorgestel. Daar word verwag dat die werk soos in hierdie proefskrifuiteengesit is die ontwerp van MV distribusiestelsels, veral in ontwikkelende lande, heelwat sal verbeter.
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Engelbrecht, Frank. "The comparison of AC and DC alternatives for sub-transmission networks." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52495.
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Thesis (MScEng)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: Recent advances in semiconductor technology extended the economic power range for DC transmission to just a few MW. Network planners need tools to compare AC and DC alternatives in order to find the best technical and economic solution for a specific network. TESAT, a software analysis tool, is developed to determine the optimum conductor and line technology for a network. Voltage regulation problems are identified and can be solved with network devices which have the potential to solve network problems more effectively and economically than ever before. PSAT, another software analysis tool developed in previous research, is used to model networks and support technologies. Hence, with the aid of TESAT and PSAT, line and support technologies are combined in an attempt to find the most effective solution in terms of cost and technical performance. This is demonstrated with the aid of a case study. Furthermore, interfaces between PSAT and the real world are developed. This includes an extension to the input interface of PSAT that calculates the equivalent impedances of a transmission line automatically, as well as an interface to share data between ReticMaster and PSAT. A dispersed generation and support technology database is also developed as an extension to the output interface ofPSAT.
AFRIKAANSE OPSOMMING: Onlangse vooruitgang in halfgeleiertegnologie het tot gevolg dat GS transmissie ekonomies is vir slegs 'n paar MW. Netwerkbeplanners benodig gevolglik pakette om WS en GS alternatiewe te vergelyk vir 'n spesifieke netwerk. In hierdie tesis is 'n analitiese sagteware-pakket (TESAT) dus ontwikkelom die optimale geleier en lyntegnologie VIr 'n netwerk te bepaal. Spanningsregulasie-probleme word geïdentifiseer en opgelos met netwerktoestelle wat die potensiaal het om netwerkprobleme meer doeltreffend en ekonomies as ooit tevore op te los. PSAT, 'n ander analitiese sagteware-pakket wat in vorige navorsing ontwikkel is, word dan ook gebruik om netwerke en steuningstegnologieë te modelleer. Dus word PSA T en TESA T gebruik om lyn- en steuningstegnologieë te kombineer. Die doel hiervan is om die mees doeltreffende oplossing in terme van kostes en tegniese werksverrigting te vind. Dit word met behulp van 'n gevallestudie gedemonstreer. Verder word koppelvlakke tussen PSA T en die eksterne wêreld ontwikkel. Dit sluit in: (a) 'n uitbreiding van die intreekoppelvlak van PSAT wat die ekwivalente impedansie vir 'n transmissielyn outomaties bereken; (b) die koppelvlak om data te deel tussen PSAT en ReticMaster. 'n Verspreide generasie- en steuningstegnologie databasis is uiteindelik ook ontwikkel as 'n uitbreiding van die uittreekoppelvlak van PSAT.
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Yoon, Yong Tae. "Electric power network economics : designing principles for a for-profit independent transmission company and underlying architectures for reliability." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8620.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (leaves 231-237).
In this thesis we examine the problem of designing architecture of an electric power network with the emphasis on transmission provision that supports various electricity market structures while ensuring the system wide reliability, following the electric power industry restructuring process. Specifically, the thesis proposes a possible regulatory incentive-based framework critical for creating a for-profit independent transmission company (ITC), and defines the role of ITC under the newly introduced regulatory framework, such that an adequate level of transmission capacity is provided for trading energy services between generators and loads over long-term. Before the restructuring process all of the electric services are provided by a so-called vertically integrated utility. A vertically integrated utility is a monopolistic entity who is responsible for meeting the region-wide demand for electricity at some acceptable quality by designing and operating entire generation, transmission and distribution assets within a regional electric power network. A vertically integrated utility fulfills its responsibilities by first projecting the demand of its customers over some period of time ( typically for the next 5 to 10 years) often assuming inelasticity. Then, based on the load projection, the utility plans for additional generation necessary for meeting the demand over the same period. Due to the lack of practical means of storing electricity and the uncertainty in equipment (both generation and transmission) availability, the adequate generation reinforcement includes not only the increase in projected demand but also the sufficient amount of reserves. Under the restructuring process, a completely new environment is created for producing, delivering and consuming electric power. A market is implemented for efficient trading of energy, and a vertically integrated utility is functionally unbundled into generation, transmission and distribution sectors by divesting the generation and distribution assets to many market participants including its affiliates. In the market the newly formed generation companies compete with other generation companies to provide energy to individual distribution companies who serve the ultimate consumer loads. The transmission asset owner and the network operator then together become a transmission provider (TP) who exists as a natural monopoly and provides network capacity to generation and distribution companies under the strict oversight of a regulator. With the introduction of a market mechanism there are a couple of new categories of uncertainties that are not encountered before the restructuring process, namely regulatory uncertainties and the market designs. It is asserted that these uncertainties play a critical role along with the well recognized uncertainties in equipment status/functionality in determining system wide efficiency as well as reliability in the operation and planning of an electric power network in the new environment. In dealing with the regulatory uncertainties, the price-cap regulation (PCR) scheme is suggested to replace the traditional cost-of-service regulation. Due to the particular characteristics of the industry including the lack of practical means of storing electricity and the lack of directly controlling the transmission path, some modifications to the conventional form of PCR scheme are necessary before actual application. In this thesis a practicable PCR scheme is proposed for regulating the operation and planning of a TP, which establishes the framework necessary for creating a for-profit ITC. In dealing with the uncertainties in market designs, the thesis introduces a usable business model for an ITC and the transmission products to be provided by this ITC. It is asserted that much of uncertainties in network usage, due to constantly changing supply and demand of the network users, can be eliminated through offering longer term transmission contracts by the ITC. A liquid market for these transmission contracts is essential for information revelation on the supply and demand of network users. The thesis proposes a workable mechanism for designing the market for transmission. In dealing with the uncertainties in equipment status/functionality, the thesis only suggests that there is a strong need for analytical tools in accurately computing the operational limit on power transfer through transmission lines within the network. Much work is needed for re-visiting the (short-term) reliability standards created under the old industry regime since various contractual agreements among the market participants now have very different interpretation on how the uncertainties in equipment status/functionality need to be handled. An active future research is urged for defining the market mechanisms essential for unbundling reliability in parallel to the functional unbundling. As attempted in this thesis, we believe that any proposed designs for electricity market structures should be examined with a clear understanding of the implications on the overall industry performance, as well as with an understanding of the implications on the individual industry participants, such as power suppliers, provider of wires, and consumers. Particular emphasis should be on understanding the long-term (in contrast to only short-term) effects of various changes on the adequacy of supply and evolution of the grid necessary to support the long-term needs of the energy markets. It will take some deep thinking and patience to get the entire electric power industry to function properly following the restructuring process.
by Yong Tae Yoon.
Ph.D.
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Mbango, Fessor. "Investigation into alternative protection solutions for distribution networks." Thesis, Cape Peninsula University of Technology, 2009. http://hdl.handle.net/20.500.11838/1107.
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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2009Recently, due to concerns about the liberalization of electricity supply, deregulation and global impact on the environment, securing a reliable power supply has become an important social need worldwide To ensure this need is fulfilled, detailed investigations and developments are In progress on power distribution systems protection and the monitoring of apparatus which Is part of the thesis. The main objective of a protection schemes is mainly to keep the power system stable by isolating only the affected components or the section of the electricity network in which the fault has developed while allowing the rest of the network to continue operating. It is important to note that the protection equipment does not prevent faults from occurring, but it limits the damaging effect of the fault and protects other healthy equipment. This is only achieved if the protection system of the electrical network involved complies with the requirements and purpose of the electrical protection standards. These requirements include the Operational speed, Reliability, Security and Sensitivity. In conventional substations that are still existing Within the utilities networks, a number of long cables are then used to complete the links between substation equipment in order for them to communicate (hardwired). This method is uneconomical and is being phased out completely in the near future. Over the last few years a new standard for substation automation communication has been developed Within the International Electrotechnical Commission (IEC), the IEC 61850. This standard defines the integration requirements of multi-vendor compliant relays and other lED's for multiple protection schemes as well as control and automation techniques. In this particular thesis, Distribution protection is the area of interest, particularly the application of Time and Overcurrent protection schemes. A look into different protection alternatives and the application of new technologies for Electrical Power Distribution Systems that unify protection and control units so that they can be incorporated into Intelligent Substation as opposed to the most existing (conventional substation) is analyzed. The proposed algorithm has been verified through simulations of the CPUT and Eureka three phase power distribution systems. A testing Lab is also part of this thesis and Is meant for experiments as well as simulation performance in order to gain knowledge and skills for designing and engineer substations with lEG 61850 standards equiprnents. The results indicate that the reduction of copper wiring cable has increased and the communication speed has improved and simplified.
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Akinsolu, Ojuetimi Ifedayo. "A design of variable transmission power control for wireless ad-hoc network." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/13559.
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Includes bibliography.Wireless Ad-hoc Network has emanated to be a promising network paradigm that can handle last mile technology due to unprecedented growth of internet users. This network is promising because it extends network to remote areas such as congested environments, rural environments etc. It is known that nodes involved in Wireless Ad-hoc Network rely on battery energy as their source of power. Energy consumption has become one of the major challenges experienced in Wireless Ad-hoc Network, which must be properly tackled. This could be traced to the effect of transmission power on the nodes in the network. Transmission power largely determines the amount of energy consumed by each node in the network. Therefore, a power control technique must be adopted in order to manage and select the optimal transmission power with respect to distance. This transmission power must be sufficient to transfer information from one node to another. Literature have proposed different algorithms for power control technique in Wireless Ad-hoc Network. Some researchers looked at the power control technique in terms of minimising energy consumed from different perspectives, which include power aware routing and power control topology management. However, most of these algorithms were applied at different layers in OSI model such as physical layer, data link layer, network layer and application layer. To achieve a reduced energy consumption at each node in the network, a novel algorithm for transmission power control was designed to select optimal transmission power. The proposed algorithm was designed in such a way that it selects transmission power based on the distance between the nodes without affecting the network throughput. Graph theory is used in this research to model the network topology, and transmission power with respect to the distance.
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Omran, Shaimaa AbdAlla Ezz Ibrahim. "Control Applications and Economic Evaluations of Distributed Series Reactors in Unbalanced Electrical Transmission Systems." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/52240.
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An important issue in today's power system is the need to analyse and determine the adequacy of transmission capacity. There is a need for approaches to increase transmission system capacity without construction of new transmission facilities, all while assuring secure operation of the grid. New technologies can enhance efficiency and reliability, increase capacity utilization, enable more rapid response to contingencies, and increase flexibility in controlling power flows on transmission lines. Distributed Series Reactor (DSR) control is a new smart grid technology that can be applied to control flows in the transmission system. DSRs can be used to balance phase flows in a single line as well as to control the distribution of flow in parallel flow paths.
This dissertation investigates the Design of Distributed Series Reactors (DSRs) on transmission lines and provide guidelines and considerations for their implementation in bulk power system transmission networks to control power flow to: increase the exisiting transmission capacity utilization, alleviate overloads due to load growth and contingencies, and mitigate the effects of unbalanced voltages, unbalanced transmission line impedances and unbalanced loads by balancing flows in the phases of an unbalanced line.
This dissertation provides several DSR System Design aspects; for a single line by performing an experiment for EHV and high voltage three parallel transmission lines, and for lines within the boundaries of a power system by deployment of DSRs over the IEEE 39 bus system that is modified and modelled as a 3-phase unbalanced transmission model with 345 kV lines that accounts for tower geometry and as a balanced, 3-phase model that is derived from the unbalanced, 3-phase model, and finally for lines within a control area and a set of tie lines among control areas by deployment of DSRs over a real system control area and the tie lines connecting this area to other power pool areas.
For all experiments and simulations in this dissertation lines are modelled as 3-phase lines. The DSR system design for Unbalanced vs. Balanced 3-phase systems (Unbalanced immittance, Unbalanced load) are examined. Also the Distributed vs. Lumped models for 3-phase systems are tested. Comparison between DSR system design and transposition for voltage balancing was performed. The effect of bundling the conductors for DSR system design was investiagted.
In this dissertation an economic evaluation of DSR System Design for parallel lines and for the IEEE 39 bus three-phase unbalanced line model for N-1 criterion contingency with load growth is performed. The economic evaluation performed for the DSR system design of a power system versus new transmission line construction showed that DSRs can be cost effective in managing load increases from year to a year, and thus avoid larger investments in new line construction until load expectations are proven to be true. Thus, a major value of DSRs is handling load growth in the short term, delaying larger investments.
Although many aspects of DSR control implementation have yet to be explored, this work has demonstrated the fundamental concept is sound and the economics are compelling.Ph. D.
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Qiao, Wei. "Integrated control of wind farms, facts devices and the power network using neural networks and adaptive critic designs." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/29716.
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Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.Committee Chair: Ronald G. Harley; Committee Member: David G. Taylor; Committee Member: Deepakraj M. Divan; Committee Member: Ganesh Kumar Venayagamoorthy; Committee Member: Thomas G. Habetler. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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MARTINS, Cláudio Roberto Medeiros de Azevedo Braga. "ALOCAÇÃO DOS CUSTOS DO SISTEMA DE TRANSMISSÃO DE ENERGIA ELÉTRICA CONSIDERANDO A SEGURANÇA." Universidade Federal do Maranhão, 2013. http://tedebc.ufma.br:8080/jspui/handle/tede/1776.
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CNPQ
After implantation of the new economic model for power systems, a fair remuneration strategy of transmission companies has become a matter of great importance. This remuneration should be performed by system users, who must pay proportionally to its network usage. However, there is still no consensus about wich is the best criterion to be adopted to allocate these costs. The most widely used methods take into account the power ows only at normal operating conditions. however, it is recognized that the transmission system is planned and operated to accommodate power also at contingency scenarios, which requires additional transmission capacity. Moreover, part of the idle capacity is due to the characteristics of network investments and uncertainty in relation to demand. Thus, the costs allocated by these methods may not re ect the actual usage of the system. In this context, this work presents a transmission cost allocation method that takes into consideration all these network characteristics. The total costs are decomposed into three components, each of these associated with a part of the transmission capacity of the system and its function. These costs are then allocated based on their system usage in diferent operating scenarios. To validate the proposed method, tests are performed on small and medium power systems. Comparisons are established with some methods more used in the literature, where it is observed that the proposed method provides complete consistency with the expected results for the problem. It was also found that this method offers subsidies to consumers allowing them to define their security requirements.
Com a implantação do novo modelo econômico nos sistemas de potência, a adequada remuneração das empresas provedoras de serviços de transmissão tem se tornado um assunto de grande importância. Esta remuneração deve ser realizada pelos usuários do sistema, que devem pagar proporcionalmente ao seu grau de utilização da rede. No entanto, ainda não há um consenso do melhor critério a ser adotado para alocar estes custos. Os métodos mais utilizados levam em consideração os uxos de potência apenas quando a rede opera em condições normais. No entanto, sabe-se que o sistema de transmissão é planejado e operado para acomodar os uxos também em cenários de contingência, o que exige capacidade adicional de transmissão. Além disso, parte da capacidade ociosa é devido às características dos investimentos no setor e à incerteza em relação à demanda. Desta forma, os custos alocados por estes métodos pode não re etir a real utilização do sistema. Neste contexto, este trabalho apresenta um método de alocação dos custos pelo uso da transmissão que leva em consideração todas estas características da rede. Os custos totais são decompostos em três componentes, cada uma destas relacionada com parte da capacidade de transmissão do sistema e sua função. Estes custos são então alocados aos usuários da rede com base no seu grau de utilização do sistema em diversos cenários de operação. Para validar o método proposto, são realizados testes em sistemas de potência de pequeno e médio porte. Comparações são estabelecidas com alguns dos métodos mais aplicados na literatura, onde constata-se que o método proposto apresenta total coerência com os resultados esperados pelo problema. Veri ca-se ainda que este método oferece subsídios aos consumidores para que estes possam de nir quais seus requisitos de segurança.
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Kreikebaum, Frank Karl. "Control of transmission system power flows." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50392.
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Power flow (PF) control can increase the utilization of the transmission system and connect lower cost generation with load. While PF controllers have demonstrated the ability to realize dynamic PF control for more than 25 years, PF control has been sparsely implemented.
This research re-examines PF control in light of the recent development of fractionally-rated PF controllers and the incremental power flow (IPF) control concept. IPF control is the transfer of an incremental quantity of power from a specified source bus to specified destination bus along a specified path without influencing power flows on circuits outside of the path.
The objectives of the research are to develop power system operation and planning methods compatible with IPF control, test the technical viability of IPF control, develop transmission planning frameworks leveraging PF and IPF control, develop power system operation and planning tools compatible with PF control, and quantify the impacts of PF and IPF control on multi-decade transmission planning.
The results suggest that planning and operation of the power system are feasible with PF controllers and may lead to cost savings. The proposed planning frameworks may incent transmission investment and be compatible with the existing transmission planning process. If the results of the planning tool demonstration scale to the national level, the annual savings in electricity expenditures would be $13 billion per year (2010$). The proposed incremental packetized energy concept may facilitate a reduction in the environmental impact of energy consumption and lead to additional cost savings.
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Tinarwo, Loyd. "Development of methodologies for deploying and implementing local & medium area broadband PLC networks in office and residential electric grids." Thesis, University of Fort Hare, 2008. http://hdl.handle.net/10353/83.
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The use of electrical networks for telecommunications has a long history. It has been known since the beginning of the twentieth century [Ahola03]. The idea of using electrical networks for broadband communications arose in the 1990s [Hrasnica et al 04]. Recent and growing research interest has indicated that PowerLine Communications (PLC) is the threshold for achieving broadband delivery particularly in very dispersed and low teledensity areas. Currently, there are numerous PLC trials and commercial deployments underway inside and outside South Africa. Nevertheless, these PLC deployments are very isolated, done without clear methodology and performance remains bound to the physical layout of the electrical network. Because of that high bandwidth broadband PLC systems are prone to poor performance and this in turn limits the acceptance and deployment of this emerging alternative broadband technology. Though, PLC technical challenges are being addressed, there has been little analysis and research work that is focused on the “Development of Methodologies for Deploying and Implementing Local & Medium Area Broadband Power Line in Residential and Office Electric Grids” that would lead to broadband PLC being adopted and be of greater use to non-broadband communities of South Africa. PLC is a term describing several different systems using electrical grid distribution wires for simultaneous distribution of data by superimposing an analog signal [Hrasnica et al 04]. The research proposed and presented broadband PLC methodologies for typical medium voltage and local voltage PLC networks. These methodologieswere implemented and experimented with in configurations which closely mirrored residential and office settings through laboratory and multibuilding experiments using commercial 2nd Generation Mitsubishi Electric PLC technology. Research results presented not only serve to provide insight into broadband PLC but also how it handled broadband applications (communications), competed and compared with other technologies such as Ethernet LAN. In combination with networking communication theories, the research explored and analyzed the extent of PLC in providing broadband communication to residential and office electric grids at the University Fort Hare, Computer Science Department.
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Galymov, Birzhan. "Distribution Network Reconfiguration For Loss Reduction By Multi-branch Exchange Method." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614663/index.pdf.
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As structure and size of electric power distribution systems are getting more complex, distribution automation schemes become more attractive. One of the features that is desirable in an automated system is feeder reconfiguration for loss reduction. Loss reduction can make considerable savings for a utility and results in released system capacity. There is also improved voltage regulation in the system as a result of reduced feeder voltage drop.
In this thesis, multi branch exchange algorithm is introduced to solve the network reconfiguration for loss reduction problem. The proposed technique is based on heuristic techniques applied to constraint satisfaction optimization problems. A critical review of earlier methods related with feeder reconfiguration is presented. A computer program was developed using Matlab to simulate this algorithm and results of simulations demonstrate its advantages over single branch exchange method. Moreover, the results show that the final configuration is independent of the initial configuration and give assurance that any solution offered will have a radial configuration with all loads connected.
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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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Lustosa, Leonardo Silva. "Calculo dos parametros de linhas de transmissão trifasicas atraves das tensões e correntes em seus terminais." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260350.
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Orientadores: Jose Pissolato Filho, Sergio KurokawaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: O objetivo deste trabalho é calcular os parâmetros longitudinais e transversais de linhas de transmissão trifásica a partir das correntes e tensões nas fases das mesmas. Serão utilizadas equações desenvolvidas no domínio modal considerando as obtenções de correntes e tensões em um terminal da linha enquanto o outro terminal permanece em aberto ou em curto-circuito. Inicialmente é apresentada a teoria básica de linhas de transmissão partindo do pressuposto de que tais linhas são melhores representadas através do modelo de parâmetros distribuídos. Assim através da análise de circuitos elétricos e das leis de Kirchhoff são encontradas as equações diferenciais de segunda ordem de tensão e corrente que caracterizam a linha de transmissão. Em seguida é apresentada a metodologia para cálculo dos parâmetros da linha que utiliza a idéia de impedância equivalente de circuito aberto e curto-circuito quando um dos terminais está em aberto e em curto-circuito respectivamente. Utilizando o Toolbox SimPowerSystem do MatLab são simuladas a obtenção das correntes em linhas de transmissão trifásica de 330 kV, 440 kV e 500 kV, todas com comprimento igual a 500 km. De posse de tais correntes são calculados os parâmetros das linhas de transmissão e comparados com seus valores reais, mostrando a viabilidade da metodologia empregada e que o erro obtido com tal metodologia é menor do que o erro entre os parâmetros reais das linhas após construção e seus parâmetros de projeto existente nos bancos de dados das empresas.
Abstract: The objective of this work is to calculate the longitudinal and transversal transmission line parameters using phase currents and voltages. Developed equations are used, in the modal domain, considering current and voltages found between a line terminal and an open line terminal, and a short-circuit terminal. . Initially, the basic transmission line theory is presented assuming that these lines are best represented by distributed parameters model. Therefore, through the analysis of electric circuits and Kirchhoff's laws , second order differential equations for voltage and current are found, which characterizes the line transmission. Next it is shown the method to calculate the line parameters, which uses the concept of open circuit and short-circuit equivalent impedance when one of the terminals is open or in short-circuited respectively. Using the Toolbox of MatLab, SimPowerSystem, estimated currents are simulated in a three-phase transmission line of 330 kV, 440 kV and 500 kV, all with the length of 500 km. The found values are used to calculate parameters of lines transmission and to compared them with their real values, showing that the calculation is possible and that the error obtained with this method is smaller than an error between the real line parameters after construction and those of existing project in the data base of companies.
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica
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Chen, Sheng. "Future development trends of optical transport network infrastructure an infrastructural framework for metropolitan-based optical transport networks : a field test of a Chinese ISP and a case study of a Chinese electrical power company /." Access electronically, 2006. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20070822.115714/index.html.
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Lazaro, Orlando. "CMOS inductively coupled power receiver for wireless microsensors." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51874.
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This research investigates how to draw energy from a distant emanating and alternating (i.e., AC) magnetic source and deliver it to a battery (i.e., DC). The objective is to develop, design, simulate, build, test, and evaluate a CMOS charger integrated circuit (IC) that wirelessly charges the battery of a microsystem. A fundamental challenge here is that a tiny receiver coil only produces mV's of AC voltage, which is difficult to convert into DC form. Although LC-boosted diode-bridge rectifiers in the literature today extract energy from similar AC sources, they can do so only when AC voltages are higher than what miniaturized coils can produce, unless tuned off-chip capacitors are available, which counters the aim of integration. Therefore, rather than rectify the AC voltage, this research proposes to rectify the current that the AC voltage induces in the coil. This way, the system can still draw power from voltages that fall below the inherent threshold limit of diode-bridge rectifiers. Still, output power is low because, with these low currents, small coils can only extract a diminutive fraction of the magnetic energy available, which is why investing battery energy is also part of this research. Ultimately, the significance of increasing the power that miniaturized platforms can output is higher integration and functionality of micro-devices, like wireless microsensors and biomedical implants.
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Barlow, Jeffrey L. "Characterizing Dynamic Power and Data Rate Policies for WirelessUSB Networks." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1479.pdf.
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Silva, Jesús, Naveda Alexa Senior, Palma Hugo Hernández, Núẽz William Niebles, and Núẽz Leonardo Niebles. "Temporary Variables for Predicting Electricity Consumption Through Data Mining." Institute of Physics Publishing, 2020. http://hdl.handle.net/10757/652132.
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In the new global and local scenario, the advent of intelligent distribution networks or Smart Grids allows real-time collection of data on the operating status of the electricity grid. Based on this availability of data, it is feasible and convenient to predict consumption in the short term, from a few hours to a week. The hypothesis of the study is that the method used to present time variables to a prediction system of electricity consumption affects the results.
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Bressam, Wagner Caldas. "Utilizando chaves ópticas para controle de qualidade de serviços em redes inteligentes." Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/2538.
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Redes inteligentes de distribuição de energia fornecem serviços com o potencial de aumentar a eficiência energética e a qualidade de vida da sociedade, mas possuem requisitos severos de tempo de resposta, confiabilidade, escalabilidade e QoS. As chaves ópticas são dispositivos comutadores de caminhos em fibras ópticas popularmente utilizados para trocas físicas de rotas. Neste trabalho sugere-se utilizar estes dispositivos para ativamente reorganizar uma rede com o objetivo de diminuir a latência de comunicação, visando atender aos requisitos de comunicações dos serviços de redes inteligentes. Foram estudadas as características de protocolos de roteamento conhecidos e aplicou-se o algoritmo de Dijkstra na criação de quatro heurísticas de otimização dos caminhos máximos em redes com chaves ópticas. Simulações realizadas mostram que as heurísticas propostas reduzem o número de saltos nos caminhos máximos, levando à redução de latência. É sugerida a continuação deste estudo aperfeiçoando as heurísticas propostas com outros mecanismos de otimização e diferentes métricas, como redução de congestionamento de tráfego e de consumo de energia na rede.Smart grid networks provide services with the potential to increase energy efficiency and the quality of life of society, but have strict requirements regarding response time, reliability, scalability and QoS. The optical switches are fiber optic switching devices commonly used for physical route changing. In this study, it is suggested to use these devices to actively rearrange a network in order to reduce the communication latency, to meet the communications requirements of smart grid services. The characteristics of known routing protocols have been studied and the Dijkstra algorithm has been applied at the creation of four heuristics that aim to optimize the maximum paths in networks with optical switches. The simulations show that the heuristics reduce the maximum number of hops in the paths, leading to reductions in latency. It is suggested the continuation of this study improving the heuristics with other optimization engines and different metrics, such as reducing traffic congestion and energy.
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Benedik, Christopher. "Modeling and Minimization of Integrated Circuit Packaging Parasitics at Radio Frequencies." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1376605018.
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Mora, Flórez Juan José. "Localización de faltas en sistemas de distribución de energía eléctrica usando métodos basados en el modelo y métodos basados en el conocimiento." Doctoral thesis, Universitat de Girona, 2006. http://hdl.handle.net/10803/7735.
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La calidad de energía eléctrica incluye la calidad del suministro y la calidad de la atención al cliente. La calidad del suministro a su vez se considera que la conforman dos partes, la forma de onda y la continuidad. En esta tesis se aborda la continuidad del suministro a través de la localización de faltas. Este problema se encuentra relativamente resuelto en los sistemas de transmisión, donde por las características homogéneas de la línea, la medición en ambos terminales y la disponibilidad de diversos equipos, se puede localizar el sitio de falta con una precisión relativamente alta. En sistemas de distribución, sin embargo, la localización de faltas es un problema complejo y aún no resuelto. La complejidad es debida principalmente a la presencia de conductores no homogéneos, cargas intermedias, derivaciones laterales y desbalances en el sistema y la carga. Además, normalmente, en estos sistemas sólo se cuenta con medidas en la subestación, y un modelo simplificado del circuito. Los principales esfuerzos en la localización han estado orientados al desarrollo de métodos que utilicen el fundamental de la tensión y de la corriente en la subestación, para estimar la reactancia hasta la falta. Como la obtención de la reactancia permite cuantificar la distancia al sitio de falta a partir del uso del modelo, el Método se considera Basado en el Modelo (MBM). Sin embargo, algunas de sus desventajas están asociadas a la necesidad de un buen modelo del sistema y a la posibilidad de localizar varios sitios donde puede haber ocurrido la falta, esto es, se puede presentar múltiple estimación del sitio de falta.
Como aporte, en esta tesis se presenta un análisis y prueba comparativa entre varios de los MBM frecuentemente referenciados. Adicionalmente se complementa la solución con métodos que utilizan otro tipo de información, como la obtenida de las bases históricas de faltas con registros de tensión y corriente medidos en la subestación (no se limita solamente al fundamental). Como herramienta de extracción de información de estos registros, se utilizan y prueban dos técnicas de clasificación (LAMDA y SVM). Éstas relacionan las características obtenidas de la señal, con la zona bajo falta y se denominan en este documento como Métodos de Clasificación Basados en el Conocimiento (MCBC).
La información que usan los MCBC se obtiene de los registros de tensión y de corriente medidos en la subestación de distribución, antes, durante y después de la falta. Los registros se procesan para obtener los siguientes descriptores: a) la magnitud de la variación de tensión ( dV ), b) la variación de la magnitud de corriente ( dI ), c) la variación de la potencia ( dS ), d) la reactancia de falta ( Xf ), e) la frecuencia del transitorio ( f ), y f) el valor propio máximo de la matriz de correlación de corrientes (Sv), cada uno de los cuales ha sido seleccionado por facilitar la localización de la falta. A partir de estos descriptores, se proponen diferentes conjuntos de entrenamiento y validación de los MCBC, y mediante una metodología que muestra la posibilidad de hallar relaciones entre estos conjuntos y las zonas en las cuales se presenta la falta, se seleccionan los de mejor comportamiento.
Los resultados de aplicación, demuestran que con la combinación de los MCBC con los MBM, se puede reducir el problema de la múltiple estimación del sitio de falta. El MCBC determina la zona de falta, mientras que el MBM encuentra la distancia desde el punto de medida hasta la falta, la integración en un esquema híbrido toma las mejores características de cada método. En este documento, lo que se conoce como híbrido es la combinación de los MBM y los MCBC, de una forma complementaria.
Finalmente y para comprobar los aportes de esta tesis, se propone y prueba un esquema de integración híbrida para localización de faltas en dos sistemas de distribución diferentes. Tanto los métodos que usan los parámetros del sistema y se fundamentan en la estimación de la impedancia (MBM), como aquellos que usan como información los descriptores y se fundamentan en técnicas de clasificación (MCBC), muestran su validez para resolver el problema de localización de faltas. Ambas metodologías propuestas tienen ventajas y desventajas, pero según la teoría de integración de métodos presentada, se alcanza una alta complementariedad, que permite la formulación de híbridos que mejoran los resultados, reduciendo o evitando el problema de la múltiple estimación de la falta.
Power quality includes the supply and customer support quality. The supply quality considers two aspects, the wave shape and continuity. In this thesis the fault location problem, topic related with supply continuity is considered.
Fault location is a relatively solved problem in power transmission systems, due to the homogeneous characteristics of the power line, measurements in both terminals and also the availability equipment such as fault locators normally included in distance relays. However, in power distribution systems the fault location is a complex problem which remains unsolved. The complexity is mainly because the presence of laterals, load taps, non homogeneous conductors, unbalances in the system and load. In addition, these power systems only have measurements at the substation and a simplified model of the power network. The main efforts to solve this problem have been oriented to the development of impedance based methods. Because of the reactance estimation makes possible the estimation of the distance to the faulted node by using the circuit model, those methods are considered as Model Based Methods (MBM). However the main drawbacks are related to the requirement of a good system model and to the possibility of multiple estimation of the location of the fault due to the three-shape of such networks.
As a result, in this thesis an analysis and a comparative test between several MBM frequently cited is presented. In addition, the solution of the fault location is complemented by using methods which use more than the rms values of current and voltage obtained from fault databases. As tool to relate this information with the fault location, two classification techniques are used and tested (LAMDA and SVM). These relate the voltage and current characteristics to the faulted zone and are denoted in this document as Classification Methods Based on the Knowledge (CMBK).
The information used by CMBK is obtained from current and voltage fault registers measured at the distribution substation, before, during and after the fault. These registers are pre-processed to obtain the following characteristics or descriptors: a) The magnitude of the voltage variation between the steady states of fault and pre-fault ( dV ), b) the magnitude of the current variation between the steady states of fault and pre-fault ( dI ), c) the magnitude of the apparent power variation between the steady states of fault and pre-fault ( dS ), d) the magnitude of the reactance as seen from the substation ( Xf ), e) the frequency of the transient caused by the fault ( f ), and f) the maximum eigenvalue of the correlation matrix of the currents ( Sv ). By using these descriptors, several training and validation sets were used with CMBK and by means of a proposed methodology it is shown how to relate these sets with the faulted zone and also to select those which offer the best performances.
The application results demonstrate how by combining the MBM with the CMBK it is possible to reduce the multiple estimation of the fault location. The CMBK is used to determine the faulted zone while the MBM finds the distance from the measurement point to the faulted node. Thus the integration in a hybrid approach uses the best characteristics of each method. In this document, the term hybrid is used to describe the complementary combination of MBM and CMBK.
Finally and aimed to compare the thesis results, an integration hybrid scheme to fault location is proposed and tested in two different power distribution systems. Both, methods which use the system parameters and are based on the impedance estimation (MBM), and those which use the information represented by the signal descriptors and are based in classification techniques (CMBK) have shown the capability to solve the problem of fault location. The two proposed methodologies have advantages and drawbacks, but according to the integration theory presented, high complementarity has been reached. This makes possible the development of a hybrid approach used to avoid or reduces the multiple estimation of the fault location.
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Cui, Xian. "Efficient radio frequency power amplifiers for wireless communications." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1195652135.
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Gardner, Robert Matthew. "A Wide-Area Perspective on Power System Operation and Dynamics." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26779.
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Classically, wide-area synchronized power system monitoring has been an expensive task requiring significant investment in utility communications infrastructures for the service of relatively few costly sensors. The purpose of this research is to demonstrate the viability of power system monitoring from very low voltage levels (120 V). Challenging the accepted norms in power system monitoring, the document will present the use of inexpensive GPS time synchronized sensors in mass numbers at the distribution level. In the past, such low level monitoring has been overlooked due to a perceived imbalance between the required investment and the usefulness of the resulting deluge of information. However, distribution level monitoring offers several advantages over bulk transmission system monitoring. First, practically everyone with access to electricity also has a measurement port into the electric power system. Second, internet access and GPS availability have become pedestrian commodities providing a communications and synchronization infrastructure for the transmission of low-voltage measurements. Third, these ubiquitous measurement points exist in an interconnected fashion irrespective of utility boundaries. This work offers insight into which parameters are meaningful to monitor at the distribution level and provides applications that add unprecedented value to the data extracted from this level. System models comprising the entire Eastern Interconnection are exploited in conjunction with a bounty of distribution level measurement data for the development of wide-area disturbance detection, classification, analysis, and location routines.
The main contributions of this work are fivefold: the introduction of a novel power system disturbance detection algorithm; the development of a power system oscillation damping analysis methodology; the development of several parametric and non-parametric power system disturbance location methods, new methods of power system phenomena visualization, and the proposal and mapping of an online power system event reporting scheme.Ph. D.
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Picorone, Antonio Angelo Missiaggia. "Comunicação digital em canais PLC: técnicas de transmissão, detecção e caracterização de canais PLC outdoor brasileiros." Universidade Federal de Juiz de Fora (UFJF), 2014. https://repositorio.ufjf.br/jspui/handle/ufjf/4168.
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Esta tese discute a medição e a caracterização das redes de distribuição de energia elétrica de baixa tensão (RDE-BT) e externa (outdoor) como meio de comunicação de dados para sistemas power line communication (PLC). São apresentados e discutidos diversos parâmetros obtidos a partir de uma campanha de medição realizada na RDE-BT de uma concessionária brasileira. Dentre os parâmetros analisados destacam-se o tempo de coerência, banda de coerência, espalhamento do atraso, comprimento da resposta ao impulso do canal e capacidade do canal, quando se considera as bandas de frequências de 1,7 a 30 MHz, 1,7 a 50 MHz e 1,7 a 100 MHz. As análises estatísticas evidenciam o potencial da rede de energia elétrica como meio de comunicação e discute os limites dessa potencialidade. Além disso, são propostos modelos de densidade espectral de potência dos ruídos, caracterização esparsa de canais PLC e proposto um modelo para geração de canais PLC variantes no tempo, cujo tempo de coerência entre as realizações dos canais é controlado. A estimação de canais PLC é apresentada como uma oportunidade de aplicação das técnicas de amostragem compressiva. Os resultados relacionados com as modelagens propostas constituem um ferramental de grande utilidade para projetar e analisar o desempenho de sistemas PLC.
This dissertation aims at discussing the measurement and characterization of outdoor electric power grid of low voltage as communication medium (power line communication - PLC). Statistical analyses carried out on several parameters such as average channel gain, coherence time, coherence bandwidth, delay spread, length of the channel impulse response, and channel capacity, when it is considered the frequency bands from 1.7 to 30 MHz, from 1.7 up to 50 MHz, and from 1.7 up to 100 MHz, are presented. These analyses reveal the circumstances in which outdoor and low-voltage electric power grids can be advantageous to support a reliable and efficient PLC system operation. Moreover, power spectral density models of additive noise and sparse representation of PLC channels are proposed. Also, a PLC time-varying channels model generator that makes use of coherence time is introduced. The proposed model generator, which is validated with measured PLC channels, is an effective tool to carry out performance analysis of PLC systems. Finally, PLC channel estimation is highlighted as an opportunity for the application of compressive sampling-based techniques. The use of traditional OFDM - based channel estimation techniques and the ones based on compressive sensing gives some directions for advancing channel estimation techniques for PLC channels.
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Lee, Cheuk-wing. "Transmission expansion planning in a restructured electricity market." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38959410.
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Sozer, Sevin Park Chan S. "Transmission expansion planning to alleviate congestion in deregulated power markets." Auburn, Ala., 2006. http://repo.lib.auburn.edu/Send%206-15-07/SOZER_SEVIN_35.pdf.
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Yu, Chang. "An investigation of subsynchronous oscillation of AC/DC power systems modeling and analysis /." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B37151885.
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Salem, M. M. "Two level state estimation for large electric power systems." Thesis, University of Strathclyde, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372189.
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Zhang, Xiaodong. "Power system transmission enhancement through storage." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-11242009-020211/.
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Zabel, D. F. "Structure-borne sound transmission within electric power steering systems." Thesis, University of Salford, 2018. http://usir.salford.ac.uk/48186/.
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Transfer path analysis (TPA) is an established and valuable tool in the automotive industry, to determine the contributions of structure-borne sound sources to receiver responses at target positions. The classical TPA approach is based on contact forces at the interface between source and receiver to characterise the dynamic loads induced by the source and frequency response functions (FRFs) to quantify the transfer paths of the sound from the interface locations to the target positions. With knowledge of the determined contributions it is then possible to decide whether source loads or FRFs must be improved to optimise the target quantities. Recently a timesaving improvement to classical TPA has been proposed, where the loads are characterised using the in-situ blocked force method, so that dismantling of source and receiver is not necessary. This method is therefore called in-situ TPA. However, if the contributions of internal structure-borne sound sources to the overall vibro-acoustic behaviour of a product are desired it is of benefit if the target quantities are blocked forces. Thus it would be possible to virtually couple the product with the properties of an overall receiver. Therefore this thesis presents a TPA approach called “blocked force transmissibility transfer path analysis” (bfTPA). In this context, the proposed internal-source-path-receiver-model (ISPRM) poses the theoretical basis of bfTPA. The aim of the presented novel TPA is to determine the contribution of internal structure-borne sound sources to an overall target quantity of a product. The presented approach uses the vector of in-situ blocked forces measured externally at the contact interface of the overall product and a corresponding set of “blocked force transmissibility” (BFT) functions relating the external coupling degrees of freedom (DOFs) to the internal source DOFs in order to propagate the external in-situ blocked forces back to multiple internal in-situ blocked forces. To prove the methodology of the presented approach three case studies, which increase in complexity, were carried out experimentally. The case studies concern a beam and an electric power steering system with paraxial servo unit (EPSapa), respectively. EPSapa systems consist of multiple embedded vibrational components which are defined as “internal sources”. The electric motor, the ball nut assembly and the toothed belt are identified as the main internal sources of an EPSapa system. Hence they are characterised by means of experimentally determined blocked forces. For the determination, micro electro mechanical systems (MEMS) accelerometers are embedded at the so called “internal interfaces”. This poses a novel application of the in-situ method in combination with the dealing of continuous and revolving internal interfaces. Concluding a further application of the bfTPA methodology is presented. It allows the external in-situ blocked forces of EPS systems or other products to be predicted based on internal insitu blocked forces and the BFT functions within internal receivers such as housings, for instance. Hence, the proposed approach is called “virtual component assembly”. It offers the advantage to synthesize a virtual EPS system based on the in-situ blocked forces of its components which are determined on test benches.
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Yan, Yonghe, and 嚴勇河. "A multi-agent based approach to transmission cost allocation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B3124256X.
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Zahra, Fathima. "Artificial neural network approach to transmission line relaying." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ42465.pdf.
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Lee, Cheuk-wing, and 李卓穎. "Transmission expansion planning in a restructured electricity market." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38959410.
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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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Li, Xiaojuan. "Estimations of power system frequency, phasors and their applications for fault location on power transmission lines." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0125.
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The thesis is devoted to the development of new algorithms for estimation of system frequency, power system phasors and transmission line fault location in the context of power system protection and control. A z-transform signal model combined with a nonlinear post-filtering scheme to estimate the operating frequency in a power system is first developed in the thesis. The signal model parameters are identified by an optimisation method in which the error between the model output and the actual signal that represents a voltage or current in the power system is minimised. The form and the structure of the signal model do not require iterations in the optimisation process for parameter identification. The system operating frequency is directly evaluated from the model parameters. Effects of noise and any frequency components other than the operating or supply-frequency on the accuracy are countered very effectively by applying a median post-filtering on the time series representing the frequency estimates derived from the model. Extensive simulation studies and comparisons with previously-published frequency estimation techniques confirm the high performance of the method developed in the thesis in terms of accuracy and time delay. With respect to power system phasor estimation, a method is developed based on waveform interpolation in the discrete time-domain to counter the spectral leakage errors arising in forming, by discrete Fourier transform (DFT), the supply frequency phasors representing power system voltages and currents when there are system frequency deviations from the nominal value. The interpolation scheme allows DFT evaluation to be performed with a time window length which is exactly equal to the fundamental period of the voltage or current waveform. Comparative studies presented in the thesis confirm the improvements achieved by the method proposed over other previouslypublished techniques in terms of accuracy and computing time. With the availability of accurate operating frequency and phasor estimates, an optimal fault location method based on multi-conductor distributedparameter line model is developed. The method is a general one which is applicable to any transmission line configurations, including multi-terminal lines. The fault location method is based on the minimisation of an objective function in which the fault distance is a variable. The objective function is formed from combining the phase-variable distributed-parameter equations of individual line sections from the fault point to the line terminals. The multivariable minimisation leads to high accuracy and robustness of the fault location algorithm in which any voltage/current measurement errors, including sampling time synchronisation errors, are represented in the estimation procedure as variables in addition to the fault distance. Extensive simulation studies are performed to verify that the method developed is highly accurate and robust. The thesis is supported by two international publications of which the candidate is a joint author.
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Kalantari, Amir. "Wind power integration in electrical networks with transmission congestion: operational complications and efficient solutions." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119576.
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Nature's ecological and geophysical balance, security of supply, and access to affordable electrical energy are threatened by increasing reliance on diminishing fossil fuels. These threats have motivated the consideration of alternative energy options, most notably renewables. Thus, as a clean and relatively free energy resource fairly abundant in many areas of the world, wind has gained significant attention. Variability and uncertainty of wind power, however, bring about operational challenges such as frequent cycling and suboptimum operation of conventional generating units, more reserve requirement and reduced capacity factor as well as very high or very low (even negative) energy prices due to out of merit dispatch. The more congested the power grid is, the more severe the challenges are. The added variability and uncertainty also introduce complexities into simulation tools used to study these challenges and, most notably, into unit commitment. A major concern here is the added computational burden due to the numerous probable wind power scenarios that must be examined when scheduling the ensemble of generating units for the short-term (day-ahead) operation. The thesis first studies the short-term techno-economic complications of wind integration in congested power grids using both theory and simulations. A Trans-Canadian Grid is introduced as a potential real-world example of a nation-wide balancing area whose various benefits include facilitating large-scale wind power integration. The thesis then presents two efficient variations of the unit commitment with wind power generation; (i) reduced security-constrained unit commitment or R-SCUC and (ii) generalized sigma or G-Sigma unit commitment. The first variation is based on the concept of Loadability Sets and reduces the computational burden significantly by doing away with the reserve-deployment generation variables under each individual scenario. The second variation extends the traditional 3σ approach based on the extreme levels of the single-dimensional system residual demand (demand minus wind power) to one based on the extreme levels of the random multi-dimensional bus residual demands or, alternatively, the random multidimensional system residual demand and line power flows. Core to both of these variations are transmission constraints, an aspect not treated in earlier efforts.L'équilibre écologique, la sécurité de l'approvisionnement, et l'accès à l'énergie électrique économique sont menacés par la dépendance croissante sur les combustibles fossiles, une source énergétique de plus en plus chère et introuvable. Ces inquiétudes ont motivé l'examen d'alternatives, notamment les énergies renouvelables. Or, étant une source d'énergie propre, relativement peu couteuse, et assez abondante à travers le monde, l'énergie électrique éolienne attire beaucoup d'attention. Cependant, la variabilité et l'incertitude du vent apportent des défis opérationnels tels que des fluctuations fréquentes et sous-optimales dans l'exploitation des unités conventionnelles de production. Pareillement, l'énergie électrique éolienne exige plus de réserve et donne lieu à un facteur de capacité réduit en plus qu'à des prix périodiquement très hauts ou très bas (mêmes négatifs) attribués à l'exploitation au-delà du point optimal. D'ailleurs, plus le réseau de transport est congestionné, plus les défis deviennent sévères. La variabilité et l'incertitude introduites par l'énergie éolienne augmentent également la complexité des outils de simulation utilisés pour étudier ces effets, particulièrement en ce qui concerne l'engagement des groupes pour chaque heure du jour suivant. Ce qui est particulièrement préoccupant est l'effort de calcul dû aux nombreux scénarios d'énergie éolienne qui doivent être examinés pour réaliser un tel ordonnancement. Par la voie théorique et par simulation, cette thèse étudie premièrement les complications techno-économiques à court-terme dû à l'intégration de l'énergie éolienne dans des réseaux électriques congestionnés. La notion d'un réseau transcanadien est introduite comme exemple d'un réseau couvrant un grand territoire exploité conjointement dont un avantage est la facilitation de l'intégration de l'énergie éolienne. La thèse présente alors deux variations efficaces du programme d'ordonnancement d'unités de génération en présence d'énergie éolienne : (i) l'ordonnancement sous contraintes de sécurité ou R-SCUC et (ii) l'ordonnancement par la méthode sigma généralisée. La première variation est basée sur le concept d'ensembles de faisabilité de la demande ce qui réduit la charge de calcul de façon significative en éliminant le besoin de calculer les variables de déploiement de réserve sous chaque scénario éolien. La deuxième variation étend l'approche traditionnelle 3σ basée sur les valeurs extrêmes de la demande résiduelle (demande moins production éolienne) du réseau à une méthode basée sur les valeurs extrêmes des demandes résiduelles aléatoires locales ou, alternativement, de la demande résiduelle aléatoire du réseau et des écoulements aléatoires de puissance à travers les lignes de transport. Dans ces variations, un aspect fondamental n'ayant pas été traité auparavant est la considération des contraintes de transport du réseau.
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Matevosyan, Julija. "Wind Power Integration in Power Systems with Transmission Bottlenecks." Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4108.
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Cordero, Roberto. "Estimation of transmission losses in a changing electric power industry." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39395.
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Tang, Yousin. "Power system stability in the presence of FACTS elements." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/13432.
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Wei, Ping. "A comprehensive approach to transmission pricing and its applications /." Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23765926.
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Westerlund, Per. "Condition measuring and lifetime modelling of electrical power transmission equipment." Licentiate thesis, KTH, Elektroteknisk teori och konstruktion, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-167136.
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The electric grid is important in modern society, so the outages should be few. The transmission grid should have a real high availability, since it transports electrical energy across the country. Then, it is difficult to plan outages for maintenance and installation. This thesis lists twenty surveys about failures of circuit breakers and disconnectors, with data about the cause and the lifetime. It also contains a survey of about forty condition-measuring methods for circuit breakers and disconnectors, mostly applicable to the electric contacts and the mechanical parts. As there is no published method to monitor the electric contacts at voltages around 400 kV, a system with IR sensors has been installed at the nine contacts of six disconnectors. The purpose is to avoid outages for maintenance by estimating the condition of the contacts while the disconnectors are still connected to high voltage. The measured temperatures are collected by radio and regressed against the square of the current, since the best exponent for the current was found to be 2.0. The coefficient of determination $R^2$ is high, greater than 0.9. This gives for each contact a regression coefficient, which can serve as an estimate of the condition of the contact. The higher the coefficient is, the more heat is produced at the contact, which can damage the material. This enables a ranking of the different contacts and shows which the worst ones are. This coefficient can also give a dynamic rating of the disconnector.Elnätet är viktigt i det moderna samhället, så antalet avbrott bör vara lågt. Särskilt stamnätet bör ha en särskilt hög tillgänglighet, då det transporterar elektrisk energi tvärsöver landet. Då blir det svårt att planera avbrott för underhåll och utbyggnad. Denna avhandling tar upp tjugo studier av fel i brytare och frånskiljare med data om felorsak och livslängd. Den har också en översikt av ett fyrtiotal olika metoder för tillståndsmätningar för brytare och frånskiljare, som huvudsakligen rör de elektriska kontakterna och de mekaniska delarna. Eftersom det inte finns någon beskriven metod för att övervaka elektriska kontakter för spänningar på runt 400 kV, har ett system med IR sensorer installerats på de nio kontakterna på sex frånskiljare. Målet är att minska antalet avbrott för underhåll genom att skatta skicket hos kontakterna, när frånskiljarna fortfarande är kopplade till högspänning. De uppmätta temperaturerna tas emot genom radio och behandlas genom regression mot kvadraten av strömmen, då den bästa exponenten för strömmen visade sig vara 2,0. Förklaringsfaktorn $R^2$ är hög, över 0,9. För varje kontakt ger det en regressionskoefficient, som blir en skattning av kontaktens skick. Ju högre koefficienten är, desto mer värme utvecklas det i kontakten, vilket kan leda till skador på materialet. Kontakternas olika koefficienter ger en rankordning dem och därmed en möjlighet att prioritera vilken frånskiljare som ska underhållas först. Systemet kan också användas för att minska eller öka den tillåtna strömmen baserat på skicket.
QC 20150522