Dissertations / Theses on the topic 'Three-phase power supply system'
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Jacobs, D. M. (Danver Maxwill). "Voltage control of medium to high power three-phase inverter supply systems." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52608.
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Thesis (MScEng)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: In this thesis a new voltage control method is developed for a three-phase inverter supply system. The inverter supply system consist of a Permanent Magnet Generator, a three-phase rectifier, a three-phase inverter plus LC-filter and a three-phase transformer in series. This system supplies power to a network or to a stand-alone load. The main focus of this thesis is on the control aspects of the inverter and the LC-filter. Different voltage control systems are investigated and compared to each other. From these methods the proposed voltage control method is developed where only the output voltages are measured to establish good voltage control. All these voltage control methods are also simulated with a software package. The proposed voltage control method compares very well with other voltage control methods. The results that are obtained in the simulations are satisfactory. The proposed voltage control method is also implemented in an 8 kW laboratory scale model and, again, very good practical results are obtained. A TMS320F240 nsp controller is used to implement the proposed voltage control method. The controller compensates well for load steps, and these results compare well to an alternative voltage control method, which was also evaluated practically.
AFRIKAANSE OPSOMMING: In hierdie tesis IS 'n nuwe spanningsbeheermetode ontwikkel VIr 'n drie-fase wisselrigter kragtoevoerstelsel. Die wisselrigter kragtoevoerstelsel bestaan uit 'n Permanent Magneet Generator, 'n drie-fase gelykrigter, 'n drie-fase wisselrigter plus Le-filter, en 'n drie-fase transformator in serie. Hierdie stelsel voorsien krag aan 'n netwerk sowel as aan 'n alleenstaande las. Die hooffokus van hierdie tesis is op die beheeraspekte van die wisselrigter en Le-filter. Verskillende spanningsbeheermetodes is deeglik ondersoek en vergelyk met mekaar. Uit hierdie metodes is dan die voorgestelde beheermetode ontwikkel waar slegs die uittreespanning gemeet word om goeie spanningsbeheer te kan doen. Al hierdie spanningsbeheermetodes is dan gesimuleer met 'n sagteware pakket. Die voorgestelde spanningsbeheermetode vergelyk baie goed met die ander spanningsbeheermetodes. Die resultate verky in die simulasies is ook baie bevredigend. Die voorgestelde beheermetode is ook geïmplementeer op 'n 8 kW laboratorium skaalmodel en weereens is baie goeie praktiese resultate verky. 'n TMS320F240 DSP-beheerder is gebruik om die voorgestelde beheermetode mee te implementeer. Die beheerder kompenseer baie goed vir lastrappe en vergelyk ook goed met 'n ander spanningsbeheermetode wat prakties ge-evalueer is.
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Cheng, Limin. "A universal controller for a single-phase uninterruptible power supply system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ42361.pdf.
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Mesbahi, Abdessamad. "Deterministic and Stochastic Economic Modeling of Hybrid Power Supply System with Photovoltaic Generators." Master's thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/42555.
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Relevance of research. Due to the rapid deployment of the non-dispatchable (intermittent) generation sources in the smart grid, such as integration of the photovoltaic power plants and wind turbines in the distribution systems; this caused a problem of the uncertainty increase of simulation results for decision-making for power supply systems, these uncertainties of power systems are getting more and more notice. At the same time, the classical power systems models cannot give accurate simulation results. Wherein; it became necessary to define new models to represent the specific parameters of power system. wherein; this research reveals to the benefits of using probabilistic mathematical approaches to define and calculate the specific economic parameters, as well as the technical parameters for power supply system with the integration renewable energy generators, which are characterising by randomness and uncertainty due to the high penetration to the renewables. Monte Carlo Method, and Point Estimation Method are used to handle the uncertainties of renewable energy resources. The standard functions to represent the stochastic parameters of the model are analyzed with the use of three-point estimation technique for the distribution functions of their probable values. A synthetic skewed probability density function was analytically constructed basing on the standard normal distribution, which is suitable for analytic representation of the predicted and/or statistical random sampling of the uncertain model parameters of energy system with renewables, and analytical expressions were obtained to compute the moments of proposed synthetic probability function.
Relationship of work with scientific programs, plans, themes. is to demonstrate the possibility of describing the input parameters of the simulation Deterministic and Stochastic Modeling by probability Density Functions by the use of three-point approximation techniques and to obtain analytical expressions for the characteristics of such distributions, suitable for non-iterative (as opposed to Monte Carlo Method) probabilistic method applications, namely the Point Estimation Method.
Purpose and tasks of the research. Increasing the simulation accuracy results for estimation economic and technical parameters characterising photovoltaic power plant based on based on the life cycle model; as well as development of different algorithms based on deterministic and stochastic modeling of power system with non-dispatchable sources and minimize the computation time.
Object of research. Processes of determining the estimated technical and economic parameters characterising a photovoltaic power plant located in Ukraine basing on stochastic modeling.
Subject of research. Use of the Monte Carlo Method and Point Estimation Method to estimate the various economic and technical information characteristic of alternative power plants in order to obtain accurate simulation results.
Practical value of the results. Practical techniques of the three-point approximation are used to construct the probability density function of the model uncertain (stochastic) parameter, which dominantly influences the modeling result: an event occurrence probability, the result attainability, whatsoever. This technique is an effective tool for the practical evaluating of an uncertain value of a technological or economic factor of material and/or economic object, and widely used for overall Levelized Energy Cost (LCOE – LEC) which is directly or indirectly engaged into analytic representation of the power systel model. Usually, the model of a kind is designed to solve technical and/or economic problem by means of Deterministic and Stochastic Modeling.
Scientific novelty of the obtained results is the development of algorithms and mathematical solutions using a probabilistic approach basing Point Estimation Method instead of Monte Carlo Melthod to obtain more accurate estimation simulation results, as well as to obtain computational results in less time for useful decision-making in alternative power plant projects.
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Loubser, Karl Albie. "An experimental study of an inherently-safe, natural circulating, flash-tube type system for a nuclear reactor steam supply concept." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/96050.
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Thesis (MEng) -- Stellenbosch University, 2014.ENGLISH ABSTRACT: This project investigates aspects of a novel inherently safe nuclear power steam supply system as safety is of paramount importance. The system envisaged has unique features namely: a) a two-phase flow flash-tube type natural circulating primary loop (also the secondary radioactive particle containment); b) a twophase flow thermosyphon heat pipe type heat exchanger secondary loop is used to transfer heat from the primary loop to the steam generators, thereby physically separating the two flow streams from one another; c) a natural convection air cooled condenser for the removal of the reactor’s residual heat; d) a unique core using TRISO type fuel (acting as the primary radioactive particle containment) with life of at least 8.9 years; e) a steel containment vessel acting as a tertiary radioactive product containment; f) a concrete containing structure with air vents to allow air to pass over the main steel containment vessel for cooling purposes in the case of an emergency, and for the removal of parasitic heat during operation. In particular the primary and secondary loops of the proposed system are investigated. This is done by design, construction and testing of a small scale experimental set-up of the primary and secondary loops as well as the development of theoretical models for the two loops. A literature survey focusing on nuclear technology, thermosyphon loops, natural circulating loop instabilities, heat pipes, and two-phase flow modelling is presented to give a brief overview of the technologies as well as tools used in the work undertaken. Observations of the inside flow behaviour of the primary loop experimental set-up were made possible by windows providing many insights into the inner workings, such as plume formation and geysering. The transient response of the secondary heat pipe loop start-up is also investigated. A thermal resistance theoretical model was developed for the secondary loop using heat transfer formulae from theory as well as experimentally semiempirical correlated formula. Different states of operation of the secondary loop were observed during testing with the theoretical model of the condensing regime correlating well, two-phase regime correlating acceptably and liquid regime correlating poorly to experimental results and thus were modelled using an experimentally determined overall heat transfer coefficient. The secondary loop model of the liquid regime is coupled with the primary loop theoretical model to predict the system’s performance. A homogeneous, one-dimensional, simple theoretical model for the primary loop was derived and computer simulated. The results did not compare well with experimental results for single phase flow and failed to capture the onset of two-phase flow. The assumptions of one dimensional model with a unidirectional flow, a hydrostatic pressure problem, a constant volumetric flow rate and the inability of the implementation of the code to handle expansion are noted as some of the flaws in the theoretical model. The following recommendations are made: a more advanced design of the pressuriser should be incorporated into the experiment; the secondary loop’s theoretical model should be characterised under a broader set of operating conditions; the computer program can be used as the basis for further research and implementation of alternative solution algorithms and models.
AFRIKKANSE OPSOMMING: Hierdie projek ondersoek aspekte van ’n ongewone, essensieel veilige kernkrag stoomtoevoer-stelsel, omdat veiligheid van kardinale belang is. Die stelsel wat voorgestel is, het unieke eienskappe, naamlik: a) ’n twee-fasevloei flits-buistipe natuurlik sirkulerende primêre lus (wat ook die sekondêre inperking van radioaktiewe materiaal bevat); b) ’n twee-fasevloei termo-heweleffek sekondêre lus hitte-pyp hitte-uitruiler word gebruik om die hitte vanaf die primêre lus oor te dra na die stoomkragopwekkers en daardeur word die twee strome se vloei fisies geskei van mekaar; c) ’n natuurlike konveksie lugverkoelde kondensor word gebruik vir die verwydering van die reaktors se oortollige hitte; d) ’n unieke kern gebruik TRISO-tipe brandstof (wat as die primêre inperking van radioaktiewe materiaal optree) met ’n lewe van minstens 8.9 jaar; e) ’n inperkingshouer van staal wat optree as ’n tersiêre radioaktiewe produkhouer; f) ’n betonstruktuur met lugventilasie om toe te laat dat lug oor die hoof staalhouer vloei vir verkoeling in ’n noodgeval, en vir die verwydering van parasitiese hitte tydens werking. Hoofsaaklik word die primêre en sekondêre lusse van die voorgestelde stelsel ondersoek. Dit word gedoen deur die ontwerp, konstruksie en die toets van ’n eksperimentele opstelling van die primêre en sekondêre lusse op klein skaal, sowel as die ontwikkeling van teoretiese modelle vir die twee lusse. ’n Literatuurstudie wat fokus op kerntegnologie, termo-heweleffeklusse, natuurlik sirkulerende lus instabiliteit, hitte-pype, en twee-fase vloeimodellering word aangebied om ’n kort oorsig te gee van die tegnologie, sowel as gereedskap gebruik in die werk wat onderneem is. Om die interne vloeigedrag van die primêre lus se eksperimentele opstelling waar te neem, word daar gebruik gemaak van vensters wat dien as ’n manier om die innerlike werking van die proses soos pluimvorming en die kook van die water in die warmwaterkolom te toon. Die oorgangsreaksie van die sekondêre hittepyplus aanvangs is ook ondersoek. ’n Teoretiese termiese weerstandmodel is ontwikkel vir die sekondêre lus met behulp van hitte-oordragformules waarvoor hitte-oordragteorie gebruik is, wat met eksperimentele semi-empiriese formules gekorreleer is. Verskillende toestande van die sekondêre lus se werking is waargeneem gedurende die toetse. Die teoretiese model het goed met die kondensasiestaat gekorreleer, terwyl by die twee-fasewerkswyse aanvaarbare korrellasies aangetref is en die uiteindelike vloeitoestand swakker gekorrelleer het met eksperimentele resultate en dus gemodelleer is met behulp van die NTU-effektiwiteitsmetode. Die sekondêre lusmodel van die vloeistoftoestand is gekoppel met die primêre lus teoretiese model om die werking van die stelsels te voorspel. ’n Homogene een-dimensionele eenvoudige teoretiese model van die primêre lus is afgelei en ’n rekenaar simulasie is uitgevoer. Die resultate vergelyk nie goed met die eksperimentele resultate vir enkelfasevloei en kon nie die aanvang van twee-fasevloei beskryf nie. Die aannemings van ’n een-dimensionele model met eenrigting vloei, ’n hidrostatiese druk probleem, ’n konstant volumetries vloeitempo en die onvermoë van die implementering van die kode om uitbreiding te hanteer is bekend as ’n paar van die foute in die teoretiese model. Die volgende aanbevelings word gemaak: ’n meer gevorderde ontwerp van drukreëlaar moet in die eksperiment ingesluit word; die sekondêre lus se teoretiese model moet gekenmerk word onder ’n wyer stel bedryfsomstandighede, en die rekenaar program kan gebruik word as die basis vir verdere navorsing en die implementering van alternatiewe algoritmes en modelle.
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Сиротин, Юрий Александрович. "Компенсация и учет реактивной мощности в электротехнических системах с несимметричными режимами." Thesis, НТУ "ХПИ", 2014. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21116.
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Диссертация на соискание ученой степени доктора технических наук по специальности 05.09.03 - электротехнические комплексы и системы. - Национальный технический университет "Харьковский политехнический институт". - Харьков, 2015.
Диссертационная работа посвящена решению важной научно-технической проблемы создания обобщенной теории мощности (ТМ), единого комплексного подхода к компенсации и учету неактивных составляющих полной мощности (ПМ) для обеспечения оптимального режима потребления электрической энергии (ЭЭ) в точке подключения неидеальной нагрузки к сети с несимметричным напряжением. На основе теоретических исследований, использующих метод ортогонального разложения векторов мгновенных значений 3-фазного тока и напряжения, получена обобщенная векторная математическая модель (ВММ), которая классифицирует электроэнергетические режимы (ЭР) в 3-фазной схеме электроснабжения с помощью векторной мгновенной мощности (ММ). Сформулированы и обоснованы предложения политики повышения качества поставки и потребления электроэнергии в 3-фазной сети, сочетающие установку поставщиком в каждой точке подключения потребителя счетчика, измеряющего каждую ЭКТ, заключение публичного договора, в котором предусмотрена оплата каждой ЭКТ по своему тарифу, установки потребителем КУ, применение компенсации неактивных составляющих ПМ на каждом уровне для уменьшения групповых потерь в сетях поставщика. Предложенная политика позволит учесть разную степень влияния ЭКТ на качество электроэнергии и обеспечит потребителю выбор выгодного для него способа потребления электроэнергии, стимулирует установку КУ, а поставщику обеспечит надежную методологию повышения качества электроэнергии в рамках несимметрии нагрузки и напряжения.Thesis for a Doctor’s degree in Engineering Sciences by specialty 05.09.03 - Electrical Engineering Complexes and Systems. - National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2015. The dissertation is devoted an important scientific and technical issues to improve the power quality of supply and consumption (SC) in three-phase networks through further development of die power theory, development of methods and ways of compensation, proposals for the accounting and payment of the inactive components of the apparent power (AP). A generalized mathematical model (GMM) of electric power processes (EPP) in a 3-phase SC scheme was developed. The model of 3-wire circuit is provided by a special (О-balanced) mode of the model 4-wire circuit The developed GMM classifies the SC modes using the vectorial instantaneous power (IP) and summarizes the class of models used in the theory of IP. For sinusoidal mode with asymmetric voltage the refines vectorial mathematical model (VMV) 3-phasors (complex rms vectors) was created. The analytical expressions for the integral characteristics of the classified modes are founded and their relationship with standard IP and vectorial IP are established. With asymmetrical voltage and asymmetrical loading a sinusoidal mode can be both unbalanced and pulsed. Each mode is represented by its power equation and the equivalent orthogonal decomposition of the 3-phase current Both decompositions are used to create the optimal mode of SC with a constant IP at asymmetrical voltage. The proposed compensator provides the non-puised energy supply with the highest possible power factor and with the same average (active) power as the initial current. Based on the evaluation and calculation of the power equation components of a unbalanced mode was developed a methodology for calculating the loss of the measuring selection. A methodology and technique of analytical calculation of additional losses on the passport data of the connected electrical equipment was proposed. Formulated and proved offers on differential measurement and payment of the energy components of AP will stimulate consumer sets the compensator, and provide a reliable methodology for improving the quality of SC (within unbalance loading and voltage).
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Beber, DG. "DSP controlled three phase to single phase uninterruptible power supply." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/5244.
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Includes bibliographical references.With the increase in use of electronic equipment such as personal computers, network stations and AC drive conrollers, an increased "polution" of the AC mains has resulted in the form of unwanted harmonics generated by the switching currents associated with these devices. Combined with the problem of mains "pollution" is the problem of balancing a large number of single phase loads onto a three phase supply, such as in a large computer network. This has resulted in more frequent supply voltage failure, causing substantial data and financial loss and in the extreme case death due to hospital equipment not being powered. Thus the need for an uninterruptible power supply (UPS) which is capable of resolving these problems. Taking these considerations into account, a three to single phase converter topology was developed and tested, using a Texas Instruments TMS320F243 Digital Signal Processor (DSP) for control of the system. The topology is based on a technique that utilises minimal semiconductor devices whilst still allowing for sinusoidal current to be drawn from the mains supply.
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Danko, Donald. "Configurable Frequency and Voltage Three Phase Power Supply." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1559166225004371.
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Magozore, Caxton. "DSP phase angle controlled three phase to single phase uninterruptible power supply." Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/5177.
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Uys, Jacobus Johannes. "Dynamic digital control schemes for three-phase UPS inverters." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52810.
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Thesis (MScEng)--University of Stellenbosch, 2002.ENGLISH ABSTRACT: This thesis presents the design and implementation of a voltage controller for an Uninterruptible Power Supply (UPS) Inverter. The inverter is capable of producing a nearly sinusoidal output voltage waveform, thereby keeping the Total Harmonic Distortion (THD) to a minimum. Digital controllers introduce a time delay in the control law that causes system instability. Various control techniques, which includes Pade approximations and system augmentation, are investigated to eliminate the effect of the time delay. These controllers employ classical control as well as modem control techniques. The selection of the various control parameters is verified by mathematical equations. A load-disturbance compensation scheme, implementing feed-forward and gain scheduling, is also developed to improve voltage distortion when varying loads, such as non-linear loads, are connected to the system. It is shown that the constructed pulse-width modulated (PWM) control scheme can achieve fast dynamic response as well as a low THD.
AFRIKAANSE OPSOMMING: Hierdie verhandeling ondersoek die ontwerp en implementering van 'n spanningsbeheerder vir 'n ononderbroke kragtoevoer omsetter. Die stelsel produseer 'n uittree spannigsgolfvorm met 'n lae Totale Harmoniese Distorisie (THD). Digital beheerders veroorsaak 'n tydvertraging in die beheerwet wat stelsel onstabiliteit kan veroorsaak. Verskeie beheertegnieke wat gebaseer is op die Pade benaderings van die tydvertraging en stelsel aanpassings, is ondersoek. Hierdie beheerders maak gebruik van klassieke en moderne beheertegnieke. Die seleksie van die verskeie beheerderveranderlikes word gestaaf deur wiskundige vergelykings. Spannigsvervorming word tot 'n minimum beperk deur gebruik te maak van 'n lasveranderings-kompensasietegniek wat onderskeidelik vorentoe-voer en aanwins skedulering implementeer. Verder word daar bewys dat die pulswydte modulasie (PWM) beheerskema vinnige dinamiese gedrag asook 'n lae THD bewerkstellig.
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Karshenas, Hamid Reza. "Input/output harmonic free current link three-phase AC power supply." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ28287.pdf.
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Cetinkaya, Suleyman. "Repetitive Control Of A Three-phase Uninterruptible Power Supply With Isolation Transformer." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608150/index.pdf.
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A repetitive control method for output voltage control of a three phase uninterruptible power supply (UPS) with isolation transformer is investigated. In the method voltage control loop is employed in the stationary dq frame. The controller eliminates the periodic errors on the output voltages due to inverter voltage nonlinearity and load disturbances. The controller design and implementation details are given. The controller is implemented on a 5-kVA UPS prototype which is
constructed in laboratory. Linear and nonlinear loads for balanced and unbalanced load operating conditions are considered. The steady-state and dynamic performance of the control method are investigated in detail. The theory of the control strategy is verified by means of simulations and experiments.
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Pande, Manish. "Three-phase voltage-type AC to DC power supply with improved performance." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0018/NQ35276.pdf.
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Драбик, Владислав Русланович, and Drabyk Vladyslav. "Проект енергоефективної системи електропостачання кормоцеху." Master's thesis, ЗМІСТ ВСТУП 7 1 АНАЛІТИЧНА ЧАСТИНА 9 1.1 Загальна характеристика господарства ТОВ «Агрокорм» 9 1.2 Аналіз і оцінка заходів електрозбереження та вирівнювання добового графіка електричних навантажень промислових підприємств 11 1.3 Оптимізація добового графіка електричного навантаження 16 2 НАУКОВО-ДОСЛІДНА ЧАСТИНА 20 2.1 Оптимізація показників добового графіка електричного навантаження кормоцеху 20 2.1 Оптимізація показників добового графіка електричного навантаження кормоцеху 25 3 ТЕХНОЛОГІЧНА ЧАСТИНА 29 3.1 Розрахунок електричних навантажень силової мережі кормоцеху 29 3.2 Розрахунок освітлювальної мережі 34 3.3 Розрахунок і вибір пускозахисної апаратури силових і освітлювальних мереж 39 3.3.1. Вибір пускозахисної апаратури для силового устаткування 39 3.3.2 Вибір пускозахисної апаратури для освітлювального обладнання. 41 3.3.3 Перевірка на узгодження струмів уставок ПЗА і тривало допустимих струмів провідників. 41 4 ПРОЕКТНО-КОНСТРУКТОРСЬКА ЧАСТИНА 45 4.1 Розробка системи електропостачання кормоцеху 45 4.1.1 Визначення розрахункової потужності на введенні. 45 4.1.2 Вибір коефіцієнта потужності. 50 4.1.3 Вибір трансформаторної підстанції 51 4.1.4 Вибір проводу і розрахунок мережі 0,4 кВ на падіння напруги. 52 4.2 Вибір лічильників для обліку електроенергії 53 6 4.2.1 Багатофункціональний лічильник електричної енергії серії SL7000 Smart 54 4.3 Заходи по компенсації реактивної потужності у кормоцеху 57 4.4 Перевірка вибраної пускозахисної апаратури кормоцеху на автоматичне спрацьовування і селективність роботи 59 4.4.1 Розрахунок струмів короткого замикання 59 4.4.2 Перевірка ПЗА на автоматичне спрацьовування і відключаючу здатність 62 5 СПЕЦІАЛЬНА ЧАСТИНА 65 5.1 Інтегрована модель графіка електричного навантаження кормоцеху з врахуванням споживачів-регуляторів 65 5.2 Дослідження графіка електричного навантаження кормоцеху 67 5.3 Порівняння показників графіка електричного навантаження кормоцеху до і після блоку оптимізації 71 6 ОБГРУНТУВАННЯ ЕКОНОМІЧНОЇ ЕФЕКТИВНОСТІ 74 Економічна ефективність роботи кормоцеху при різних тарифних системах (диференційованих по зонах доби) оплати електричної енергії 74 7 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ 82 7.1 Заходи безпеки при роботі кормоцеху ТОВ “Агрокорм” 82 7.2 Розрахунок захисного заземлення 85 7.3 Загальні положення з евакуації при виникненні надзвичайної ситуації 89 8 ЕКОЛОГІЯ 92 8.1 Аналіз впливу виробничих дій підприємства на довкілля 92 8.2 Заходи і засоби захисту довкілля від викидів підприємства 94 ЗАГАЛЬНІ ВИСНОВКИ ДО ДИПЛОМНОЇ РОБОТИ 96 ПЕРЕЛІК ПОСИЛАНЬ 98, 2019. http://elartu.tntu.edu.ua/handle/lib/29598.
Full textAbstract:
У дипломній роботі здійснено проект енергоефективної системи електропостачання кормоцеху промислового підприємства ТОВ «Агрокорм» та розглянуто заходи, що направлені на електрозбереження та вирівнювання добового графіка навантаження. Вирішені основні питання з електропостачання і захисту силового енергоощадного електрообладнання кормоцеху. Вибрано однотрансформаторну KTП 250-10/0,4 кВ. Проведений розрахунок освітлювального навантаження на базі сучасних світлодіодних промислових світильників Highbay 200. Також, проведений розрахунок струмів короткого замикання, перевірено захисну та комутаційну апаратуру на чутливість до струмів КЗ, на автоматичне спрацьовування і відключаючу здатність. Здійснилося вирівнювання нерівномірності графіка електричного навантаження за рахунок оптимізації основних критеріїв моделі оптимізації: дисперсія графіка електричного навантаження зменшилася на 26,4%, збільшився коефіцієнт заповнення та зменшився коефіцієнт максимуму.In diploma work the project of the energy-efficient system of power supply to feeding room of industrial enterprise of LTD «Agrofeed» is carried out and events that is sent to electro-maintenance and smoothing of day's load-graph are considered. The decided basic questions are from a power supply and defence of power energy-efficient electrical equipment to feeding room. The onetransformer is chosen KTS 250-10/0.4 kV. Conducted calculation of the lighting loading on the base of modern light-emitting-diode industrial lamps of Highbay 200. Also, conducted calculation of currents of short circuit, a protective and interconnect apparatus is checked for a sensitiveness to the currents of short circuit, on an automatic wearing-out and disconnecting ability. Smoothing of unevenness of chart of the electric loading came true due to optimization of basic criteria of model of optimization: dispersion of chart of the electric loading diminished on 26,4%, a fillfactor increased and the coefficient of maximum diminished.
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Raval, Chintan A. "Three-phase ac-dc power supply design and experiments using a sic based power module." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/35520.
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Master of ScienceDepartment of Electrical and Computer Engineering
Behrooz Mirafzal
The rise of Wide Band Gap (WBG) devices has brought excitement in the field of Power converters. The WBG based converter can operate at the very high frequency and temperature making them ideal to use in harsh environments. The commercialization of WBG devices such as SiC and GaN MOSFETs has made it interesting for power engineering professionals all over the world. The use of WBG devices capable of operating at high switching frequencies reduces the overall system size dramatically with added benefit of improved power quality at high temperature. The main goal of this thesis is to design and test an AC-DC converter based on a SiC power module. The designed rectifier can be considered an active rectifier equipped with a controller to constantly provide feedback for modification of switching signals to get the desired output voltage. The designed active rectifier converts the varying frequency input power supply into rectified DC voltage while keeping the power factor of the system to unity. This thesis covers elementary information on power supply design, switching schemes and design of the controller. System arrangement will provide more light on the use of Six Channel MOSFET Gate Driver from CREE with the overall experimental setup. The experimental analysis will summarize the behavior of the system where information on achieved rectification, effect on the line currents at the generator and concluding power factor representation is described.
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Небера, Ольга Алексеевна. "Совершенствование методов и средств моделирования систем электроснабжения с двигательной нагрузкой." Thesis, НТУ "ХПИ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/20002.
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Диссертация на соискание ученой степени кандидата технических наук по специальности 05.14.02 – электрические станции, сети и системы. – НТУ "ХПИ". – Харьков, 2016.
Диссертация посвящена разработке математических моделей систем электроснабжения с двигательной нагрузкой, позволяет воспроизводить как электромагнитные, так и электромеханические составляющие переходных процессов в трехфазных схемах произвольной конфигурации. Узлы двигательной нагрузки, а вместе с ними и системы электроснабжения, содержащие такие узлы, являются одним из наиболее чувствительных к нарушениям электроснабжения элементов. Предотвращение отрицательных последствий таких нарушений может быть обеспечено только путем совершенствования средств противоаварийного управления и защиты на основе результатов моделирования переходных процессов. Показано, что уровень развития современных методов и средств исследования режимов работы систем электроснабжения с двигательной нагрузкой не соответствует изменениям, которые произошли за последние десятилетия как в самих системах, так и в условиях их эксплуатации. В то время, как для решения целого ряда задач обеспечения эффективного функционирования систем электроснабжения на стадии их проектирования и эксплуатации необходимо дальнейшее развитие методов и средств математического моделирования переходных процессов в системах электроснабжения с двигательной нагрузкой. Следует также отметить, что и возможности современных ЭВМ позволяют перейти к более полным и точным моделям на основе уравнений в фазных координатах. Для повышения точности моделирования переходных процессов в системах электроснабжения с двигательной нагрузкой значение частоты необходимо иметь на каждом шаге численного интегрирования. Предложен метод определения локальных отклонений частоты в электрических системах, путем перехода от мгновенных значений параметров режима трехфазной системы к их обобщенным векторам, обеспечивающий повышение быстродействия и эффективности средств измерения и диагностики. С помощью полученной модели выполнены исследования переходных процессов в реальных системах с узлами двигательной нагрузки, возникающие при симметричных и несимметричных коммутациях в сети, которые показали её высокую достоверность и эффективность.The thesis for granting the Degree of Candidate of Technical sciences in speciality 05.14.02 - power plants, networks and systems. National Technical University "Kharkiv Politechnic Institute", Kharkiv, 2016. The thesis is devoted to the development of mathematical models of electric power supply systems with motor load that allows to reproduce electromagnetic and electromechanical components of transients in three-phase circuits of arbitrary configuration. In the work current state of the problem, existing methods and tools for simulation of power supply systems were analyzed, first time a mathematical model of transients based on equations in phase coordinates for power supply systems with static elements and rotating electrical machines was developed. Methods of forming and solutions of differential equations in phase coordinates in relation to three-phase systems were improved, method for determining parameters of elements in phase coordinates was proposed, elements of inverse matrices inductance of rotating electric machines in an analytical form were received. First time the method of determining local frequency variations in the electrical systems which provides to increase speed and efficiency of measurement and diagnostic devices was proposed.
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Zhang, Huibin. "Application of multilevel inverter as shunt active power filter in three-phase three-wire power system." Thesis, University of Strathclyde, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501797.
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This research investigates application issues of the active power filter to three-phase three-wire systems, with unbalanced, distorted loads where the line impedance gives rise to voltage distortion at the point of common coupling. Five shunt active power filters are investigated: two-level, wye connected cascaded three and five level, and diode-clamped three and five level. Capabilities of the different shunt active power filter topologies to mitigate voltage/current distortion, compensate reactive power, and balance real power from the source are investigated. Results indicate that neutral point clamped multilevel inverters have advantages over wye cascaded multilevel inverters when operating under asymmetrical load conditions.
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Wu, Zhongyu. "Synchronized Phasor Measurement Units Applications in Three-phase Power System." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/51660.
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Phasor Measurement Units (PMUs) are widely acknowledged as one of the most significant developments in the field of real-time monitoring of power system. By aligning time stamps of voltage and current phasor measurements, which are consistent with Coordinated Universal Time (UTC), a coherent picture of the power system state can be achieved through either direct measurements or simple linear calculations. With the growing number of PMUs installed or planned to be installed in the near future, both utilities and research institutions are looking for novel applications of synchrophasor measurements from these widely installed PMUs. In this dissertation, the author proposes two new PMUs measurements applications: three-phase instrument transformer calibration, and three-phase line parameter calculation with instrument transformers.
First application is to calibrate instrument transformers. Instrument transformers are the main sensors used in power systems. They provide isolation between high voltage level of primary side and metering level of the secondary side. All the monitoring and measuring systems obtain input signals from the secondary side of instrument transformers. That means when instrument transformers are not accurate, all the measurements used in power system are inaccurate. The most important job of this dissertation is to explore a method to automatically calibrate all the instrument transformers in the power system based on real-time synchrophasor measurements.
The regular instrument transformer calibration method requires the instrument transformer to be out of service (offline) and calibrated by technicians manually. However, the error of instrument transformer changes when environment changes, and connected burden. Therefore, utilities are supposed to periodically calibrate instrument transformers at least once a year. The high labor and economic costs make traditional instrument transformer calibration method become one of the urgent problems in power industry. In this dissertation we introduce a novel, low cost and easy method to calibrate three-phase instrument transformers. This method only requires one three-phase voltage transformer at one bus calibrated in advance. All other instrument transformers can be calibrated by this method as often as twice a day, based on the synchrophasor measurements under different load scenarios.
Second application is to calculate line parameters during calibrating instrument transformers. The line parameters, line impedance and line shunt admittance, as needed by utilities are generated by the computer method. The computer method is based on parameters, such as the diameter, length, material characteristics, the distance among transmission line, the distance to ground and so on. The formulas to calculate line parameters have been improved and re-modeled from time to time in order to increase the accuracy. However, in this case, the line parameters are still inaccurate due to various reasons. The line parameters errors do affect the instrument transformers calibration results (with 5% to 10% error). To solve this problem, we present a new method to calculate line parameters and instrument transformers in the same processing step.
This method to calibrate line parameter and instrument transformers at the same time only needs one pre-calibrated voltage transformer and one pre-calibrated current transformer in power system. With the pre-calibrated instrument transformers, the line parameter as well as the ratio correction factors of all the other instrument transformers can be solved automatically. Simulation results showed the errors between calculated line parameters and the real line parameter, the errors between calibrated ratio correction factors and the real ratio correction factors are of the order of 10e-10 per unit. Therefore, high accuracy line parameters as well as perfectly calibrated instrument transformers can be obtained by this new method. This method can run automatically every day. High accuracy and dynamic line parameters will significantly improve power system models. It will also increase the reliability and speed of the relay system, enhance the accuracy of power system analysis, and benefit all other researches using line parameters. New methods of calculating line parameter and the instrument transformer calibrations will influence the whole power industry significantly.Ph. D.
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Небера, Ольга Олексіївна. "Вдосконалення методів і засобів моделювання систем електропостачання з двигунним навантаженням." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/20000.
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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.14.02 – електричні станції, мережі і системи. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2016 р.
Дисертацію присвячено розробці математичних моделей систем електропостачання з двигунним навантаженням, що дозволяє відтворювати як електромагнітні, так і електромеханічні складові перехідних процесів в трифазних схемах довільної конфігурації. В роботі проведено аналіз сучасного стану проблеми та існуючих методів і засобів моделювання систем електропостачання, вперше розроблена математична модель перехідних процесів на основі рівнянь в фазних координатах для систем електропостачання зі статичними елементами та обертовими електричними машинами. Вдосконалено методи формування та рішення систем диференційних рівнянь в фазних координатах стосовно до трифазних систем, запропоновано метод визначення параметрів елементів в фазних координатах, отримані в аналітичній формі елементи зворотних матриць індуктивностей обертових електричних машин. Вперше запропоновано метод визначення локальних відхилень частоти в електричних системах, що забезпечує підвищення швидкодії та ефективності засобів вимірювання та діагностики.The thesis for granting the Degree of Candidate of Technical sciences in speciality 05.14.02 - power plants, networks and systems. National Technical University "Kharkiv Politechnic Institute", Kharkiv, 2016. The thesis is devoted to the development of mathematical models of electric power supply systems with motor load that allows to reproduce electromagnetic and electromechanical components of transients in three-phase circuits of arbitrary configuration. In the work current state of the problem, existing methods and tools for simulation of power supply systems were analyzed, first time a mathematical model of transients based on equations in phase coordinates for power supply systems with static elements and rotating electrical machines was developed. Methods of forming and solutions of differential equations in phase coordinates in relation to three-phase systems were improved, method for determining parameters of elements in phase coordinates was proposed, elements of inverse matrices inductance of rotating electric machines in an analytical form were received. First time the method of determining local frequency variations in the electrical systems which provides to increase speed and efficiency of measurement and diagnostic devices was proposed.
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Ehlers, P., CG Richards, and DV Nicolae. "Small power, three to one phase matrix converter for wind generators." International Review of Electrical Engineering, 2013. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001152.
Full textAbstract:
This paper investigates the concept of an isolated small wind power system based on
a three-phase generator and a direct ac-to-ac conversion. The ac-to-ac conversion is performed
by a matrix converter and thus removing the need of a large smoothing capacitor in the typical
rectifier-inverter solution. The paper is briefly presenting the operation for a particular topology
of a three-phase to single-phase matrix converter. The control of this conversion ensures system’s
frequency and voltage stability. Simulation results and practical results are presented to validate
the frequency and voltage regulation of the isolated power system.
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Parchure, Abhineet Himanshu. "Towards Three-Phase Dynamic Analysis of Large Electric Power Systems." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/54574.
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This thesis primarily focuses on studying the impact of Distributed Generation (DG) on the electromechanical transients in the electric grid (distribution, transmission or combined transmission and distribution (TandD) systems) using a Three Phase Dynamics Analyzer (hereafter referred to as TPDA). TPDA includes dynamic models for electric machines, their controllers, and a three-phase model of the electric grid, and performs three-phase dynamic simulations without assuming a positive sequence network model. As a result, TPDA can be used for more accurate investigation of electromechanical transients in the electric grid in the presence of imbalances.
At present, the Electromagnetic Transient Program (EMTP) software can be used to perform three-phase dynamic simulations. This software models the differential equations of the entire electric network along with those of the machines. This calls for solving differential equations with time constants in the order of milliseconds (representing the fast electric network) in tandem with differential equations with time constants in the order of seconds (representing the slower electromechanical machines). This results in a stiff set of differential equations, making such an analysis extremely time consuming. For the purpose of electromechanical transient analysis, TPDA exploits the difference in the order of time constants and adopts phasor analysis of the electric network, solving differential equations only for the equipment whose dynamics are much slower than those of the electric network. Power Flow equations are solved using a graph trace analysis based approach which, along with the explicit partitioned method adopted in TPDA, can eventually lead to the use of distributed computing that will further enhance the speed of TPDA and perhaps enable it to perform dynamic simulation in real time .
In the work presented here, first an overview of the methodology behind TPDA is provided. A description of the object oriented implementation of TPDA in C++/C# is included. Subsequently, TPDA is shown to accurately simulate power system dynamics of balanced networks by comparing its results against those obtained using GE-PSLF®. This is followed by an analysis that demonstrates the advantages of using TPDA by highlighting the differences in results when the same problem is analyzed using a three-phase network model with unbalances and the positive sequence network model as used in GE-PSLF®. Finally, the impact of rapidly varying DG generation is analyzed, and it is shown that as the penetration level of DG increases, the current and voltage oscillations throughout the transmission network increase as well. Further, rotor speed deviations are shown to grow proportionally with increasing DG penetration.Master of Science
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Sane, Hemant. "Power supply noise analysis for 3D ICs using through-silicon-vias." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33875.
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3D design is being recognized widely as the next BIG thing in system integration. However, design and analysis tools for 3D are still in infancy stage. Power supply noise analysis is one of the critical aspects of a design. Hence, the area of noise analysis for 3D designs is a key area for future development. The following research presents a new parasitic RLC modeling technique for 3D chips containing TSVs as well as a novel optimization algorithm for power-ground network of a 3D chip with the aim of minimizing noise in the network. The following work also looks into an existing commercial IR drop analysis tool and presents a way to modify it with the aim of handling 3D designs containing TSVs.
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Walraven, Justin Stewart. "Design of an Arbitrary Waveform Generator for Power System Perturbation." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/35493.
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In this thesis, the design of a voltage-source inverter (VSI)-based three-phase impedance analyzerâ s perturbation injection unit (PIU) is described including all relevant power stage and control design. Both series and shunt injection are examined from .1 Hz to 1000Hz. Both types of injection are performed using only energy from the system under test stored in a DC link capacitor. Sinusoidal, square (pulse), and chirp perturbation waveforms are explored. Results from a constructed realization of the design are presented, and the limits of the device characterized. The maximum achievable perturbation power is 10 kW in shunt and 8 kW in series on a 460 V, 100 kW bus. Using the same conditions, maximum power is achievable from 10Hz to 100Hz, at .1Hz, .72 kW is achievable, and at 1000Hz, 6.0 kW is achievable.Master of Science
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Karsli, V. M. "An investigation into real-time microcontrolled single phase uninterruptible power supply systems." Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637763.
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Recent developments in power electronic switching devices and microprocessors have led to power electronic systems with high efficiency and reliability. Today, high performance and low cost are the requirements to be met for most practical systems. This work describes the development of real-time based Uninterruptible Power Supply systems (UPS) which can operate on-line and off-line. Synchronous operation is an inevitable condition in off-line UPS systems. Here, back-synchronisation after a power failure is achieved automatically with the pre-set values. A new modified regular sampled symmetric pulse width modulation method has been developed, it has many advantages especially in low frequency applications. High switching frequency (18 kHz) reduces significantly the filtration and noise problems in UPS systems. Phase delay associated with transformer, filter, load, and control algorithm might cause drastic power failures in by-pass switches, thus to overcome this problem, phase shift control algorithms are developed. PID control algorithm is simplified for real-time on-line operation at high switching frequency. The complete system is based on a single Intel 80C196KC microcontroller chip and the developed software has the flexibility for further development. The developed system has been tested in the laboratory under linear load condition and the results are given. The test results are found to be satisfactory for most load conditions.
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Riley, J. M. "The appraisal of three gas-fired small-scale CHP systems." Thesis, Cranfield University, 1997. http://dspace.lib.cranfield.ac.uk/handle/1826/4548.
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The research in this thesis has undertaken a technical. economic and environmeiital
appraisal of three gas-fired, small-scale Combined Heat-and-Power (CHP) systenlýý
together with a study of the UK's electricity supply industry (ESi) and CHP market.
The purpose of each system is to attempt to utilise more of the heat and/or electricitY
output from the CHP unit. Within the non-technical research area, t hree
scenarios for the evolution of the ES1 have been developed to help establish llow
changes to forces acting within the industry, might affect the development of the
UK CHP market. New applications of several strategic management, alialysis tools
were used to develop and select the following scenarios: (i) 'N-ewa nd reduced ('02
limits set by the Climate Control Conference + stricter environmental legislatioil,
(ii) Changes to the Pool mechanism for pricing electricity. (iii) Business as usual.
It was concluded that in isolation scenarios I and 3 would aid the expansion of the,
CHP market, whereas scenario 2 is likely to hinder it. The selection of the scenarios
and the implications for the ESi and CHP market are supported by the opinions of
'industry specialists', which were solicited in a survey specifically undertaken for
this study.
The investigation into the first of the three technical systems involves the substitution
of two separate CHP units in place of a single larger unit. The intention
is to operate the larger of the two CHP units at maximum output to satisfy the
base heat-load and to use the second unit for meeting peak loads. The results for
five test-cases were produced via a newlY-developed predictive model, and indicated
that it is possible, for one of the case studies considered, to achieve shorter
pay-back periods when using the double-unit - with a higher availability of 9.5% -
rather than the single-unit system. In the other two cases (where CHP is a viable
economic option), longer pay-back periods ensue by the installation of the twounit
rather than the single-unit system. The operation of the two-unit system call
potentially increase energy-utilisation from the CHP units at one of the other sites'.
Furthermore, the proposed system can offer, in some cases, significant secondarý'
benefits, which could encourage a potential investor in the technology. These benefits
include the increased heat- an d-elect ri city output, increased availability from
the system, back-up from the secondary unit if one unit fails.
The second system determines the viability of an integrated small-scale CHP and
TES system. Another predictive model was developed and tested on five test -case",.
It was found that there is insufficient potential for the system and that the pot(, iitial
is limited by the following factors (i) CHP-sizing methodology, (ii) the relat IvCIN,
high capital cost for TEs hardware and installation, (iii) the relatively low econwilic
value attributed to heat and (iv) the availability of IoN%-pricedo ff-peak electricitv.
An industrial case study provided a rare and useful operational exainple of tlic
proposed system and the findings indicated that the heat-store could reduce i he
energy and monetary expenditures by up to 2.8/7c of the site's annual gas usage.
displacing approximately 30 tones Of C02 emissions each year. Howe\-er, becauýw
of the high financial cost of the TES components and installation. the pay-back
period produced would rarely be acceptable to a prospecti\-e investor. except in
exceptional circumstances.
Finally, the viability of an integrated CHP/absorption chiller systeni was in\-(, stigated.
The effectiveness of these types of systems are dependent on several factors,
namely: the source-water temperature from the hot-engine CHP unit - for a high
cop - and the cooling load at the site, the cooling demand at the site and the
temperature of the cooling water. A first-stage predictive model was developed to
determine the initial appropriateness of the installation of the integrated system
at a local hospital for the first time. The indications were that the cooling demand
was too low and the surplus waste-heat from the CHP unit insufficient to make the
system viable at the site. A second working-system was studied with a full ('02
investigation undertaken. The intention was to compare the total C02 emissions
for the integrated CHP and absorption chiller system with those for a similarl. y
sized vapour-compression system. The results indicate that the installed systc1l)
will produce 0.30kgCO2/kWhcoolth compared with 0.27 kg and 0.32kg for two different
types of vapour compression systems at design conditions. If the CHP heat
output is increased - to supply all of the heat required by the absorption chiller -
then the proposed system can displace up to 0.06 kgC02 per kWhcoolth at design
conditions and 0.10 kgC02 per kWh of cooling delivered for lower cooling water
temperatures. This represents a reduction of 22% and 40% respectively, when
compared with the vap our- compressions system.
25
Shen, Zhiyu. "Online Measurement of Three-phase AC Power System Impedance in Synchronous Coordinates." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/49258.
Full textAbstract:
Over the last two decades there has been an increased use of three-phase AC power systems that may not be connected to the main power grid, such as the power systems on more-electric airplane and all-electric ships. Power-electronic converters are usually a significant part of these systems, which provide excellent performance. But their negative incremental impedance nature increases the possibility of system instability.A small-signal analysis that uses interface impedances defined in the synchronous frame is developed by Belkhayat at Purdue in the mid-90s to access the system stability. The system impedance varies with the operating point. Thus the impedance has to be obtained online at the desired operating point, on even in situ.
Literature investigates its use with system models, but the lack of equipment to measure such impedance prevents its use in practical systems. Measurement of impedances of each component enables the prediction of system stability before building the real system. The impedance data can also be used to investigate the instability in the system after it is built. The capability of impedance measurement can save the cost and time of system integrators.
After reviewing the state-of-the-art development of impedance measurement systems, the dissertation analyzes several systematical error sources in the system, which includes the signal processing and sampling circuits, the phase estimation for coordinate transformation and the injection device connection, and proposes the solution to reduce their influence.
Improved algorithm and system architecture are proposed to increase the measurement speed and accuracy. Chirp signal is used as an excitation signal to extract impedances at a group of frequencies at one time. The use of both shunt current injection and series voltage injection improves the SNR of measured signal. Oversampling, cross-correlation and frequency domain averaging technique are used to further reduce the influence of noise.
An instrument is built based on the proposed solution. A voltage source inverter is used to generate the perturbation. A PXI computer is used for real-time signal processing. A PC is used for data post processing and measurement process control. Software is developed to fully automate the measurement. The designed unit is tested with various linear and nonlinear load. The test result shows the validity of the proposed solution.
Ph. D.
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Grossman, Hy. "A NEXT GENERATION AIRCRAFT POWER MONITORING SYSTEM." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604535.
Full textAbstract:
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, NevadaHistorically, aircraft power monitoring has required the use of multiple signal conditioning functions to measure various parameters including voltage, current, frequency and phase. This information was then post processed to determine the characteristics of the 3-phase power quality on the aircraft. Recent developments in embedded DSP processors within signalconditioning systems provide the instrumentation engineer with expanded capabilities for realtime on-board power quality monitoring. Advantages include reduced space and bandwidth requirements and minimal wiring intrusion. For each phase, output data may include peak positive and negative voltages and currents, peak-to-peak, average and RMS voltages and currents, phase power (real and apparent), phase power factor, phase period (frequency), phase shift measurement from phase 1 (the reference phase) to phase 2, and from phase 1 to phase 3. In addition, a Fast Fourier Transform (FFT) is performed on each phase voltage to provide Total Harmonic Distortion measurements. This paper describes the methods employed in the implementation of these functions on a single signal-conditioning card in order to provide detailed information about the power quality of a three-phase aircraft power source.
27
Wen, Bo. "Stability Analysis of Three-Phase AC Power Systems Based on Measured D-Q Frame Impedances." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/51202.
Full textAbstract:
Small-signal stability is of great concern for distributed power systems with a large number of regulated power converters. These converters are constant-power loads (CPLs) exhibit a negative incremental input resistance within the output voltage regulation bandwidth. In the case of dc systems, design requirements for impedances that guarantee stability have been previously developed and are used in the design and specification of these systems. In terms of three-phase ac systems, a mathematical framework based on the generalized Nyquist stability criterion (GNC), reference frame theory, and multivariable control is set forth for stability assessment. However, this approach relies on the actual measurement of these impedances, which up to now has severely hindered its applicability. Addressing this shortcoming, this research investigates the small-signal stability of three-phase ac systems using measured d-q frame impedances. Prior to this research, negative incremental resistance is only found in CPLs as a results of output voltage regulation. In this research, negative incremental resistance is discovered in grid-tied inverters as a consequence of grid synchronization and current injection, where the bandwidth of the phase-locked loop determines the frequency range of the negative incremental resistance behavior, and the power rating of inverter determines the magnitude of the resistance. Prior to this research, grid synchronization stability issue and sub-synchronous oscillations between grid-tied inverter and its nearby rectifier under weak grid condition are reported and analyzed using characteristic equation of the system. This research proposes a more design oriented analysis approach based on the negative incremental resistance concept of grid-tied inverters. Grid synchronization stability issues are well explained under the framework of GNC. Although stability and its margin of ac system can be addressed using source and load impedances in d-q frame, method to specify the shape of load impedances to assure system stability is not reported. This research finds out that under unity power factor condition, three-phase ac system is decoupled. It can be simplified to two dc systems. Load impedances can be then specified to guarantee system stability and less conservative design.Ph. D.
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Khaniya, Dina. "Development of three-phase continuation power flow for voltage stability analysis of distribution systems." Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-11142008-101009.
Full text
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Milosavljevic, Ivana. "Power Electronics System Communications." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/31218.
Full textAbstract:
This work investigates communication issues in high-frequency power converters. A novel control communication network (Power Electronics System Network or PES Net) is proposed for modular, medium and high-power, converters. The network protocol, hardware and software are designed and implemented. The PES Net runs at 125 Mb/s over plastic optical fiber allowing converter switching frequencies in excess of 100 kHz. Communication control is implemented in a field programmable gate array device. A novel synchronization method applicable to ring networks is proposed. The effect of the communication delay on the power converter operation is studied.Master of Science
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Гулак, Сергій Олександрович. "Підвищення енергетичних показників електровозів змінного струму за рахунок адаптованої до системи електропостачання компенсації реактивної потужності." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48885.
Full textAbstract:
Дисертація на здобуття наукового ступеню кандидата технічних наук (доктора філософії) за спеціальністю 05.22.09 – "Електротранспорт" 141 – електроенергетика, електротехніка та електромеханіка) – Національний технічний університет "Харківський політехнічний інститут" МОН України. Харків, 2020. Дисертація присвячена створенню наукових основ вибору оптимальних параметрів та режимів роботи системи компенсації реактивної потужності на електровозах змінного струму та адаптації роботи системи компенсації до параметрів тягового електропостачання.
Для виконання досліджень розроблені математичні та програмно-орієнтовані моделі роботи тягового та допоміжного приводу електровозу змінного струму (на прикладі електровозу ВЛ-80К). Відмінними особливостями цих моделей є можливість врахування взаємного впливу роботи тягового приводу і допоміжних агрегатів та режимів роботи електровозу. Виконано експериментальне підтвердження адекватності розроблених імітаційних моделей з реальним тяговим та допоміжним приводом для рухомого складу. На основі розроблених моделей досліджено електромагнітні процеси в тяговому та допоміжному приводах, що дозволило якісно та кількісно їх оцінити. Розроблено силову схему гібридного КРП та схему керування його активної частини. Основою системи керування є метод визначення спектрального складу тягового струму на основі алгоритму Левінсона-Дарбіна, що дозволить адаптувати роботу компенсатора до параметрів системи електропостачання. Запропоновано в системі допоміжного приводу застосувати статичний перетворювач замість фазорозчіплювача. Розрахунок втрат повної потужності до та після модернізації підтвердив економічну доцільність впровадження компенсатора реактивної потужності та застосування статичного перетворювача в системі допоміжних машин замість фазорозчіплювача. Розроблені наукові положення є ефективним інструментом модернізації існуючого парку вантажних електровозів змінного струму серій ВЛ-80Т та ВЛ-80К і створення нового електрорухомого складу залізниць. Результати дисертаційної роботи впроваджені у "Науково-дослідному та конструкторсько-технологічному інституті залізничного транспорту" АТ "Укрзалізниця" (м. Київ), ДП "Український науково-дослідницький інститут вагонобудування" (м. Кременчук) та у навчальному процесі Державного університету інфраструктури та технологій (м. Київ).Thesis for a Candidate Degree in Engineering (Doctor of Philosophy) in specialty 05.22.09 - "Electrotransport" 141 - Electric Power Engineering, Electrical Engineering and Electromechanics) - National Technical University "Kharkiv Polytechnic Institute", MES of Ukraine. Kharkiv, 2020. The dissertation is devoted to creation of scientific bases of choice of optimum parameters and modes of operation of the system of reactive power compensation on electric locomotives operating on alternating current. The factors that have the greatest impact on the quality of traction power supply from the side of the electric rolling stock of alternating current are analyzed. Factors that cause the greatest distortion of the voltage form of the catenary include higher harmonic components, which are introduced into the traction power supply system by electric rolling stock. It is shown that such factors as poor current collection, passage of electric rolling stock of the feeder zone, the presence of several units of electric rolling stock in one feeder zone, modes of operation of electric rolling stock lead to the fact that the process of voltage change in the catenary is nondeterministic for the analysis of the spectral composition of the traction current of an electric locomotive, the application of classical Fourier transform methods is incorrect. Analysis of circuit solutions for compensation of reactive power consumed by electric rolling stock of alternating current showed that to date the most optimal solution is the use of hybrid compensators. In such compensators, the passive part reduces the phase shift between the voltage of the secondary winding of the traction transformer and the traction current, and the active part removes the higher harmonic components of the traction current. The active part of the hybrid compensator is a stand-alone current inverter and an inverter control system. The control system performs spectral analysis of the traction current, forms an algorithm for the generation of autonomous inverter higher harmonics, the same amplitude but antiphase to the higher harmonics of the traction current. Existing control systems use Fourier transform methods to determine the spectral components of the traction current, but in real operating conditions of the electric rolling stock they are incorrect. It is proposed to apply the methods of correlation spectral analysis to determine the spectral components of the traction current. Mathematical and program-oriented models of work of traction and auxiliary drive of an electric locomotive of an alternating current (on the example of the locomotive VL-80k) have been created. The unique features of these models are the ability to take into account the mutual influence of the traction and auxiliary drives and the operating modes of electric locomotives. The technique of calculating the parameters of asynchronous motors for asymmetrical stator windings has been improved. The relationship between such parameters as the scattering inductance and the mutual inductance with the geometric parameters of the windings is shown. This technique was used to create a mathematical model for the drive of auxiliary machines, in particular for the simulation of the phase splitter. It is proposed to investigate electrodynamic processes in auxiliary machine actuators in steady state operation, to replace the phase splitter with an asymmetrical voltage system that feeds the motors of fans. The mutual influence of traction actuator and auxiliary motors operation was investigated. The results of the study made it possible to clarify the spectral composition of the current in the traction and auxiliary drive circuits. The use of a hybrid reactive power compensator in traction drive circuits is substantiated. The elements of the passive and active part of the compensator are calculated. A control system for the active part of the reactive power compensator has been developed, which is based on the block of determination of harmonic components of traction current and suppression in the current spectrum of zero and higher harmonic components. A new scientific approach to the determination of the spectral components of the traction current is proposed. It is based on the application of the linear prediction method of Levinson-Darbin. This approach allows to take into account the random nature of the voltage and, as a consequence, the traction current, and to adapt the work of the compensator to the voltage of the contact network. The application of this approach also allows taking into account such factors as the nature of the mode of operation of the electric locomotive, the passage of the boundaries of the sections of the contact network, etc. Adjusted mathematical model of traction actuator when using of reactive power compensator, calculated and constructed amplitude-frequency and phase-frequency spectral characteristics of voltage and current on the traction winding of the transformer. The power factor of the upgraded traction actuator is calculated. The justified is use of a static converter instead of a phase splitter in the auxiliary drive power supply system. The system of mathematical modeling of the auxiliary drive of the electric locomotive is executed; the amplitude-frequency and phasefrequency spectral characteristics of the voltage on the winding of the transformer and the current flowing through the winding of its own needs are calculated and constructed. The power factor of the upgraded auxiliary actuator is calculated. The losses of active and full power in the traction and auxiliary drives of the locomotive were calculated before and after the modernization. The dependences of the efficiency and the power factor of the drives before and after the modernization were calculated. The results obtained indicate that the efficiency of the traction drive after the use of the compensator decreased by 0,6% a factor and the power factor increased by 3,2%. Auxiliary drive efficiency after upgrading increased by 1,5%, and power factor increased by 26,4%. The developed scientific provisions are an effective tool for modernization of the existing fleet of electric locomotives of the VL-80t and VL-80k series and the creation of a new electric rolling stock of railways. The results of the dissertation were implemented at the Scientific Research Design and Engineering Institute of Railway Transport of OJSC "Ukrzaliznytsya" (Kyiv), SE "Ukrainian Research Institute of Carriage" (Kremenchuk) and in the educational process of the State University of Infrastructure and Technology (Kyiv).
31
Elwakil, Ehab. "A new converter topology for high-speed high-starting-torque three-phase switched reluctance motor drive system." Thesis, Brunel University, 2009. http://bura.brunel.ac.uk/handle/2438/3009.
Full textAbstract:
Switched reluctance motor (SRM) has become a competitive selection for many applications of electric machine drive systems recently due to its relative simple construction and its robustness. The advantages of those motors are high reliability, easy maintenance and good performance. The absence of permanent magnets and windings in rotor gives possibility to achieve very high speeds (over 10000 rpm) and turned SRM into perfect solution for operation in hard conditions like presence of vibrations or impacts. Such simple mechanical structure greatly reduces its price. Due to these features, SRM drives are used more and more into aerospace, automotive and home applications. The major drawbacks of the SRM are the complicated algorithm to control it due to the high degree of nonlinearity, also the SRM has always to be electronically commutated and the need of a shaft position sensor to detect the shaft position, the other limitations are strong torque ripple and acoustic noise effects.
32
Гулак, Сергій Олександрович. "Підвищення енергетичних показників електровозів змінного струму за рахунок адаптованої до системи електропостачання компенсації реактивної потужності." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48887.
Full textAbstract:
Дисертація на здобуття наукового ступеню кандидата технічних наук (доктора філософії) за спеціальністю 05.22.09 – "Електротранспорт" 141 – електроенергетика, електротехніка та електромеханіка) – Національний технічний університет "Харківський політехнічний інститут" МОН України. Харків, 2020. Дисертація присвячена створенню наукових основ вибору оптимальних параметрів та режимів роботи системи компенсації реактивної потужності на електровозах змінного струму. Проаналізовані фактори, що мають найбільший вплив на якість тягового електропостачання збоку електрорухомого складу змінного струму. До факторів, що вносять найбільше спотворення форми напруги контактної мережі слід віднести вищі гармонійні складові, які вносяться в систему тягового електропостачання електрорухомим складом. Показано, що такі чинники, як неякісне струмознімання, проходження електрорухомим складом фідерної зони, наявність декількох одиниць електрорухомого складу на одній фідерній зоні, режими робот електрорухомого складу призводять до того, що процес зміни напруги в контактній мережі є недетермінованим, неергодичним негаусовим процесом, при якому для аналізу спектральних складових тягового стуму електровозу застосування класичних методів перетворення Фур‘є є некоректним. Аналіз схемотехнічних рішень щодо компенсації реактивної потужності, яка споживається електрорухомим складом змінного струму, показав, що на сьогоднішній день найбільш оптимальним рішенням є застосування гібридних компенсаторів реактивної потужності (ГКРП). В таких компенсаторах пасивна частина зменшує фазовий зсув між напругою вторинної обмотки тягового трансформатора та тяговим струмом, активна частина – видаляє вищі гармонійні складові тягового струму. Пасивною частиною ГКРП є LC-фільтр, а активною - автономний інвертор струму і система керування інвертором. Система керування виконує спектральний аналіз тягового струму, формує алгоритм для генерації автономним інвертором вищих гармонік, однакових по амплітуді але протифазними до вищих гармонік тягового струму. В існуючих системах керування для визначення спектральних складових тягового струму використовуються методи перетворення Фур‘є, які в реальних умовах експлуатації електрорухомого складу дають некоректні результати. Запропоновано для визначення спектральних складових тягового струму застосувати методи кореляційного спектрального аналізу. Створено математичні та програмно-орієнтовані моделі роботи тягового та допоміжного приводу електровозу змінного струму (на прикладі електровозу ВЛ-80к). Відмінними особливостями цих моделей є можливість врахування взаємного впливу роботи тягового та допоміжного приводів, а також режимів
роботи електровозу. Доопрацьовано методику розрахунку параметрів асинхронних двигунів при
несиметричних обмотках статора. Показано взаємозв‘язок таких параметрів, як індуктивність розсіювання та взаємна індуктивність із геометричними параметрами обмоток. Ця методика використовувалась при створенні математичної моделі приводу допоміжних машин, зокрема для моделювання роботи розчіплювача фаз. Запропоновано для дослідження електродинамічних процесів в приводах допоміжних машин у сталому режимі роботи замінити розчіплювач фаз несиметричною системою напруги, яка живить мотор-вентилятори. Досліджено взаємний вплив роботи тягового приводу і приводу допоміжних машин. Результати дослідження дозволили уточнити спектральний склад струму
в ланцюгах тягового та допоміжного приводів. Розраховано елементи пасивної та активної частин ГКРП. Розроблено систему керування активною частиною ГКРП, основою якого є блок визначення гармонійних складових тягового струму та видалення із спектру струму нульової та вищих гармонійних складових.
Запропоновано новий підхід до визначення спектральних складових тягового струму, в основі якого лежить застосування методу лінійного прогнозування Левінсона-Дарбіна. Такий підхід дозволяє враховувати випадковий характер зміни напруги на струмоприймачі електровозу і, як наслідок, тягового струму, та адаптувати роботу компенсатора до параметрів напруги контактної мережі. Застосування зазначеного підходу дозволяє також враховувати такі фактори, як характер режиму роботи електровозу, прохід меж ділянок контактної мережі, тощо. Скорегована математична модель тягового приводу при застосуванні ГКРП, розраховано та побудовано амплітудно-частотні та фазо-частотні спектральні
характеристики напруги та струму тягової обмотки трансформатора. Розраховано коефіцієнт потужності модернізованого тягового приводу. Обґрунтовано застосування в системі живлення допоміжних машин
статичного перетворювача замість фазорозчіплювача. Виконано математичне моделювання системи допоміжного приводу електровозу, розраховано та побудовано амплітудно-частотні та фазочастотні спектральні характеристики напруги на обмотці власних потреб трансформатора та струму, що протікає по обмотці власних потреб. Розраховано коефіцієнт потужності модернізованого допоміжного приводу.
Розраховано втрати активної та повної потужності в тяговому та допоміжному приводах електровозу до та після модернізації. Розраховано залежності ККД і коефіцієнту потужності приводів до та після модернізації. Отримані результати свідчать про те, що ККД тягового приводу після застосування компенсатора знизився на 0,6%, а коефіцієнт потужності збільшився на 3,2%. ККД допоміжного приводу після модернізації збільшився на 1,5%, а коефіцієнт потужності – на 26,4%. Розроблені наукові положення є ефективним інструментом модернізації існуючого парку вантажних електровозів змінного струму серій ВЛ-80т та ВЛ-80к і створення нового електрорухомого складу залізниць. Результати дисертаційної роботи впроваджені у "Науково-дослідному та конструкторсько-технологічному інституті залізничного транспорту" АТ "Укрзалізниця" (м. Київ), ДП "Український науково-дослідницький інститут вагонобудування" (м. Кременчук) та у навчальному процесі Державного університету інфраструктури та технологій (м. Київ).Thesis for a Candidate Degree in Engineering (Doctor of Philosophy) in specialty 05.22.09 - "Electrotransport" 141 - Electric Power Engineering, Electrical Engineering and Electromechanics) - National Technical University "Kharkiv Polytechnic Institute", MES of Ukraine. Kharkiv, 2020. The dissertation is devoted to creation of scientific bases of a choice of optimum parameters and operating modes of system of compensation of reactive power on electric locomotives of alternating current. The factors that have the greatest impact on the quality of traction power supply from the side of the electric rolling stock of alternating current are analyzed. The factors that cause the greatest distortion of the voltage form of the catenary include the higher harmonic components, which are introduced into the traction power supply system by electric rolling stock. It is shown that such factors as poor current collection, passage of electric rolling stock of the feeder zone, the presence of several units of electric rolling stock in one feeder zone, modes of operation of electric rolling stock lead to the fact that the process of voltage change in the catenary is nondeterministic for the analysis of the spectral composition of the traction current of an electric locomotive, the application of classical Fourier transform methods is incorrect. The analysis of circuit solutions for the compensation of reactive power consumed by the electric rolling stock of alternating current showed that to date the most optimal solution is the use of hybrid reactive power compensators (НRPС). In such compensators, the passive part reduces the phase shift between the voltage of the secondary winding of the traction transformer and the traction current, the active part - removes the higher harmonic components of the traction current. The passive part of the НRPС is LC-filter, and the active stand-alone current inverter and control system of inverter. The control system of inverter performs spectral analysis of the traction current, forms an algorithm for the generation of autonomous inverter higher harmonics, the same amplitude but antiphase to the higher harmonics of the traction current. Existing control systems use Fourier transform methods to determine the spectral components of the traction current, but in real operating conditions of the electric rolling stock they are incorrect. It is proposed to apply the methods of correlation spectral analysis to determine the spectral components of the traction current. Mathematical and program-oriented models of operation of the traction and auxiliary drive of the AC electric locomotive (on the example of the VL-80k electric locomotive) were created. Distinctive features of these models are the ability to take into account the mutual influence of traction and auxiliary drives, as well as modes of operation of the electric locomotive. The method of calculating the parameters of induction motors with asymmetric stator windings has been improved. The relationship between parameters such as scattering inductance and mutual inductance with the geometric parameters of the windings is shown. This technique was used in the creation of a mathematical model of the drive of auxiliary machines, in particular for modeling the operation of the phase release. It is proposed to replace the phase release with an asymmetric voltage system that feeds the motor-fans to study the electrodynamic processes in the drives of auxiliary machines in steady-state operation. The mutual influence of the work of the traction drive and the drive of auxiliary machines is investigated. The results of the study allowed clarifying the spectral composition of the current in the circuits of traction and auxiliary drives. The elements of the passive and active parts of НRPС are calculated. A control system for the active part of the НRPС has been developed, the basis of which is a unit for determining the harmonic components of the traction current and removing zero and higher harmonic components from the current spectrum. A new approach to determining the spectral components of traction current is proposed. This approach is based on the application of the Levinson-Darbin linear prediction method. This approach allows to take into account the random nature of the voltage change at the current collector of the electric locomotive and, as a consequence, the traction current, and to adapt the operation of the compensator to the voltage parameters of the catenary. The application of this approach also allows taking into account such factors as the nature of the mode of operation of the electric locomotive, the passage of the boundaries of the catenary, and so on. The mathematical model of the traction drive when using НRPС is corrected, the amplitude-frequency and phase-frequency spectral characteristics of the voltage and current of the traction winding of the transformer are calculated and constructed. The power factor of the modernized traction drive is calculated. The use of a static converter instead of a phase breaker in the power supply system of auxiliary machines is substantiated. Mathematical modeling system of auxiliary drive of the electric locomotive is performed, amplitude-frequency and phase-frequency spectral characteristics of the voltage of the winding of the transformer's own winding and the current flowing in the winding of the own needs are calculated and constructed. The power factor of the modernized auxiliary drive is calculated. The losses of active and full power in the traction and auxiliary drives of the electric locomotive before and after the modernization are calculated. The dependences of factor efficiency and factor power of drives before and after modernization are calculated. The obtained results show that the factor efficiency of the traction drive after the application of the compensator decreased by 0,6%, and the power factor increased by 3,2%. The factor efficiency of the auxiliary drive after modernization increased by 1,5%, and the power factor - by 26,4%. The developed scientific provisions are an effective tool for modernization of the existing fleet of electric locomotives of the VL-80t and VL-80k series and the creation of a new electric rolling stock of railways. The results of the dissertation were implemented at the Scientific Research Design and Engineering Institute of Railway Transport of OJSC "Ukrzaliznytsya" (Kyiv), SE "Ukrainian Research Institute of Carriage" (Kremenchuk) and in the educational process of the State University of Infrastructure and Technology (Kyiv).
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Xu, Ye. "Kilowatt Three-phase Rotary Transformer Design for Permanent Magnet DC Motor with On-rotor Drive System." Thesis, Mittuniversitetet, Avdelningen för elektronikkonstruktion, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-27781.
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The aim of this thesis is to design a kilowatt three-phase step-down rotary transformer for a permanent magnet DC motor. The permanent magnet DC motor has an on-rotor drive system, and therefore requiring a power supply that can transfer power to its drive unit without mechanical contact. The rotary transformer has a detached magnetic coupling structure that qualifies it as a potential method for the wireless power transfer. This thesis studies the rotary transformer as a static device, focusing on its core loss. By using a transient finite element analysis of COMSOL Multiphysics and an iron loss prediction model, the rotary transformer was optimized in terms of efficiency and power density for the on-rotor drive system through proper material selection and geometry exploration. After this, a mechanical design, which based on a literature review of the influences of manufacturing processes on electrical steels, was proposed for realizing the core fabrication and the rotary transformer assembly. The results show that the rotary transformer can step down 400 V/50 Hz three-phase voltage to 13.15V in a Delta-wye connection and output 1.17kW power over an air-gap of 0.3mm with 95.94% overall efficiency. The proposed mechanical design enables the transformer to minimize the core loss and the manufacturing cost. Without using resonant inductive coupling, this transformer design simplifies the power supply for the motor, thereby decreasing the motor manufacturing and maintenance cost.
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Jain, Himanshu. "Dynamic Simulation of Power Systems using Three Phase Integrated Transmission and Distribution System Models: Case Study Comparisons with Traditional Analysis Methods." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/74234.
Full textAbstract:
Solar PV-based distributed generation has increased significantly over the last few years, and the rapid growth is expected to continue in the foreseeable future. As the penetration levels of distributed generation increase, power systems will become increasingly decentralized with bi-directional flow of electricity between the transmission and distribution networks. To manage such decentralized power systems, planners and operators need models that accurately reflect the structure of, and interactions between the transmission and distribution networks. Moreover, algorithms that can simulate the steady state and dynamics of power systems using these models are also needed. In this context, integrated transmission and distribution system modeling and simulation has become an important research area in recent years, and the primary focus so far has been on studying the steady state response of power systems using integrated transmission and distribution system models.
The primary objective of this dissertation is to develop an analysis approach and a program that can simulate the dynamics of three phase, integrated transmission and distribution system models, and use the program to demonstrate the advantages of evaluating the impact of solar PV-based distributed generation on power systems dynamics using such models. To realize this objective, a new dynamic simulation analysis approach is presented, the implementation of the approach in a program is discussed, and verification studies are presented to demonstrate the accuracy of the program. A new dynamic model for small solar PV-based distributed generation is also investigated. This model can interface with unbalanced networks and change its real power output according to the incident solar irradiation. Finally, application of the dynamic simulation program for evaluating the impact of solar PV units using an integrated transmission and distribution system model is discussed.
The dissertation presents a new approach for studying the impact of solar PV-based distributed generation on power systems dynamics, and demonstrates that the solar PV impact studies performed using the program and integrated transmission and distribution system models provide insights about the dynamic response of power systems that cannot be obtained using traditional dynamic simulation approaches that rely on transmission only models.Ph. D.
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Huang, Gang. "Compact physical models for power supply noise and chip/package co-design in gigascale integration (GSI) and three-dimensional (3-D) integration systems." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26619.
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Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.Committee Chair: Meindl, James D.; Committee Member: Bakir, Muhannad S.; Committee Member: Davis, Jeffrey A.; Committee Member: Gaylord, Thomas K.; Committee Member: Kohl, Paul A.; Committee Member: Naeemi, Azad. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Louganski, Konstantin P. "Modeling and Analysis of a Dc Power Distribution System in 21st Century Airlifters." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/35514.
Full textAbstract:
A DC power distribution system (PDS) of a transport aircraft was modeled and analyzed using MATLAB/Simulink software. The multi-level modeling concept was used as a modeling approach, which assumes modeling subsystem of the PDS at three different levels of complexity. The subsystem models were implemented in Simulink and combined into the whole PDS model according to certain interconnection rules. Effective modeling of different scenarios of operation was achieved by mixing subsystem models of different levels in one PDS model. Linearized models were obtained from the nonlinear PDS model for stability analysis and control design.
The PDS model was used to examine the system stability and the DC bus power quality under bidirectional power flow conditions. Small-signal analysis techniques were employed to study stability issues resulting from subsystem interactions. The DC bus stability diagram was proposed for predicting stability of the PDS with different types of loads without performing an actual stability test based on regular stability analysis tools. Certain PDS configurations and operational scenarios leading to instability were identified. An analysis of energy transfer in the PDS showed that a large energy storage capacitor in the input filter of a flight control actuator is effective for reduction of the DC bus voltage disturbances produced by regenerative action of the actuator. However, energy storage capacitors do not provide energy savings in the PDS and do not increase its overall efficiency.Master of Science
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Francis, Gerald. "An Algorithm and System for Measuring Impedance in D-Q Coordinates." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/26462.
Full textAbstract:
This dissertation presents work conducted at the Center for Power Electronics Systems (CPES) at Virginia Polytechnic Institute and State University.
Chapter 1 introduces the concept of impedance measurement, and discusses previous work on this topic. This chapter also addresses issues associated with impedance measurement.
Chapter 2 introduces the analyzer architecture and the proposed algorithm. The algorithm involves locking on to the voltage vector at the point of common coupling between the analyzer and the system via a PLL to establish a D-Q frame. A series of sweeps are performed, injecting at least two independent angles in the D-Q plane, acquiring D- and Q-axis voltages and currents for each axis of injection at the point of interest.
Chapter 3 discusses the analyzer hardware and the criteria for selection. The hardware built ranges from large-scale power level hardware to communication hardware implementing a universal serial bus. An eight-layer PCB was constructed implementing analog signal conditioning and conversion to and from digital signals with high resolution. The PCB interfaces with the existing Universal Controller hardware.
Chapter 4 discusses the analyzer software. Software was written in C++, VHDL, and Matlab to implement the measurement process. This chapter also provides a description of the software architecture and individual components.
Chapter 5 discusses the application of the analyzer to various examples. A dynamic model of the analyzer is constructed, considering all components of the measurement system. Congruence with predicted results is demonstrated for three-phase balanced linear impedance networks, which can be directly derived based on stationary impedance measurements. Other impedances measured include a voltage source inverter, Vienna rectifier, six-pulse rectifier and an autotransformer-rectifier unit.Ph. D.
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Zhong, Shan. "Measurement calibration/tuning & topology processing in power system state estimation." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1595.
Full textAbstract:
State estimation plays an important role in modern power systems. The errors in the telemetered measurements and the connectivity information of the network will greatly contaminate the estimated system state. This dissertation provides solutions to suppress the influences of these errors.
A two-stage state estimation algorithm has been utilized in topology error identification in the past decade. Chapter II discusses the implementation of this algorithm. A concise substation model is defined for this purpose. A friendly user interface that incorporates the two-stage algorithm into the conventional state estimator is developed.
The performances of the two-stage state estimation algorithms rely on accurate determination of suspect substations. A comprehensive identification procedure is described in chapter III. In order to evaluate the proposed procedure, a topology error library is created. Several identification methods are comparatively tested using this library.
A remote measurement calibration method is presented in chapter IV. The un-calibrated quantities can be related to the true values by the characteristic functions. The conventional state estimation algorithm is modified to include the parameters of these functions. Hence they can be estimated along with the system state variables and used to calibrate the measurements. The measurements taken at different time instants are utilized to minimize the influence of the random errors.
A method for auto tuning of measurement weights in state estimation is described in chapter V. Two alternative ways to estimate the measurement random error variances are discussed. They are both tested on simulation data generated based on IEEE systems. Their performances are compared. A comprehensive solution, which contains an initialization process and a recursively updating process, is presented.
Chapter VI investigates the errors introduced in the positive sequence state estimation due to the usual assumptions of having fully balanced bus loads/generations and continuously transposed transmission lines. Several tests are conducted using different assumptions regarding the availability of single and multi-phase measurements. It is demonstrated that incomplete metering of three-phase system quantities may lead to significant errors in the positive sequence state estimates for certain cases. A novel sequence domain three-phase state estimation algorithm is proposed to solve this problem.
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Hord, Kyle A. "MODELING AND VALIDATION OF A SYNCHRONOUS-MACHINE/CONTROLLED-RECTIFIER SYSTEM." UKnowledge, 2014. http://uknowledge.uky.edu/ece_etds/42.
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The hardware validation of a novel average-value model (AVM) for the simulation of a synchronous-generator/controlled rectifier system is presented herein. The generator is characterized using genetic algorithm techniques to fit standstill frequency response (SSFR) measurements to q and d-axis equivalent circuits representing the generator in the rotor reference frame. The generator parameters form the basis of a detailed model of the system, from which algebraic functions defining the parametric AVM are derived. The average-value model is compared to the physical system for a variety of loading and operating conditions including step load change, change in delay angle, and external closed-loop control, validating the model accuracy for steady-state and transient operation.
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Rojas, Lobos Felix Eduardo [Verfasser], Ralph [Akademischer Betreuer] [Gutachter] Kennel, and Jon [Gutachter] Clare. "A High Performance Power Supply based on a Four-Leg Three-Level NPC Converter for Non-linear and Unbalanced Systems / Felix Eduardo Rojas Lobos. Betreuer: Ralph Kennel. Gutachter: Ralph Kennel ; Jon Clare." München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1111038929/34.
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Vápeník, René. "Modelování nesymetrického třífázového vedení." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218010.
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The subject of the thesis is creation and description of mathematical model of three-phase asymmetric power line and proposal for three-phase operation calculating of the power network by variet aspects. Another component is the creation of a program in PHP, which would use this mathematical model for the calculation of the three-phase operation of the power network. Part of this work deals with derivation of matrices of elementary multipoles and their serial ordering derive complex multipoles that can be use for concentrated parameters compensation of the power lines.
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Carvalho, Hamilton Dias de. "Avaliação de desempenho do gerador de indução trifásico assimétrico conectado a uma rede monofásica - aplicações rurais." Universidade Federal de Uberlândia, 2006. https://repositorio.ufu.br/handle/123456789/14635.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThis work has for motive to obtain the project and build of an assymmetrical three-phase induction generator connected to single-phase supply system, in order to be used in rural areas. This equipment has been presented as a better alternative in relation the others proposed more commercialized at the moment, due to its robustness, low cost, less maintenance requirements and excellent performance. Firstly, in the theoric part concerned to the system it is presented a mathematical representation, frequency domain mathematical model, whose equations are performed in function of an unbalance factor in order to obtain balance three-phase voltages in the system. Then, some simulations are performed in the simulator that was developed in the Microsoft Excel program. From these implements, it is carried out study cases to prove the assymmetrical three-phase induction generator use potentialities. A prototype is projected and built, which experimental results are compared to the computer result.
O objetivo deste trabalho é obter o projeto e a construção de um gerador de indução trifásico assimétrico conectado a um sistema de distribuição de energia elétrica monofásica; visando aplicá-lo em áreas rurais. Este dispositivo, em face de sua robustez, baixo custo, menores requisitos de manutenção e bom desempenho, consiste numa alternativa bastante atrativa em relação às outras propostas existentes atualmente. O estudo teórico inicia-se através da elaboração de uma modelagem matemática para o sistema, no domínio da freqüência, cujas equações são colocadas em função de um fator indicativo do nível de desbalanceamento, visando à obtenção de tensões balanceadas na carga. Para tanto, a modelagem matemática elaborada é implementada num simulador desenvolvido no programa Microsoft Excel. A partir desta implementação, são efetuados estudos de casos no sentido de evidenciar as potencialidades do gerador assimétrico conectado a cargas rurais. Os trabalhos computacionais são devidamente validados à luz de resultados experimentais extraídos de um protótipo de equipamento concebido, projetado e construído para fins deste trabalho.
Mestre em Ciências
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Holub, Ondřej. "Proaktivní diagnostika a monitorování stavu trojfázových asynchronních motorů v průmyslovém podniku." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241220.
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This master thesis deals with the proactive diagnostics and monitoring of state of the three phase asynchronnous motors in industrial company Bosch Diesel Jihlava. In master thesis is designed diagnostics system based on the selected suitable diagnostics methods and other appropriate process monitors the status of these technical equipments.
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Leplus, François. "Sur la modélisation numérique des transformateurs monophasé et triphasé : Application aux montages redresseurs et gradateurs." Lille 1, 1989. http://www.theses.fr/1989LIL10073.
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Méthode de résolution des équations du système modélisé, indépendante de son environnement électrique, donnant un programme modulaire, utilisable dans un ensemble plus complexe. Extension de la méthode et procédure d'identification des paramètres. Expérimentation en fonctionnement redresseur et gradateur
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Chang, Tsuen-Ding, and 張村叮. "Implementation of Three-Phase Fed DC Power Supply System with High Power Factor." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/x27zfm.
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碩士中原大學
電機工程研究所
93
In this thesis, a high efficiency power supply system with high power factor is proposed for high power applications. The studied power supply system consists with a three-phase three-switch power factor corrector (PFC) and a phase-shifted zero-voltage-transition full-bridge DC/DC converter with current doubler rectification. High power factor input can be achieved by the adopted PFC circuit with a simple configuration. The phase-shifted operation of the full-bridge DC/DC converter provides the zero-voltage-switching (ZVS) features for the bridge switches to reduce the switching losses effectively. The current doubler rectification reduces significantly the secondary rectification losses. Therefore, high efficiency can be also accomplished. The detailed operating principle and design consideration of this power supply system are analyzed and described. A 1.1kW 55V/20A laboratory prototype was implemented and tested. The experimental waveforms verify the feasibility of the proposed design. The implemented power supply system exhibits optimum performances such as high power factor, high efficiency, simple configuration and high reliability.
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Wu, Wen-Chieh, and 巫文傑. "Simulation of Integrated Three-phase AC/DC Power Supply System of MRTS." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/57903918357180689620.
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碩士國立臺灣科技大學
電機工程系
88
The major purpose of this thesis is to apply a commercial circuit simulation software, Intusoft ICAP/4, to simulate the operation property of a three-phase AC/DC power supply system of the MRTS under normal and abnormal conditions, and based on the maximal DC traction demand and the electric demand of stations. The disadvantages of conventional approaches that separate the calculations of AC and DC networks and the necessary of setting the control variables of the AC/DC converters are avoided in the proposed method. First of all, the mathematical models of the major facilities of the AC/DC power supply systems of the MRTS were introduced. These equivalent circuit models were implemented by the Intusoft IsSpice. After the model of a simple converter bank was implemented. The effects of source voltage unbalance and harmonic pollution on the rectifier were evaluated. Finally, the full-scale model of the AC/DC network of the Panchiao-Nankang line of Taipei MRTS was implemented and simulated by the IsSpice. The voltage profiles, power flows and harmonics on both AC and DC networks can be obtained in a single run. The simulation results have verified the correctness and feasibility of the proposed method.
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Wang, Kuo-Cheng, and 王國丞. "Design and Implementation of Parallel Type Three-phase Uninterruptible Power Supply Systems." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/56638494191890576260.
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碩士國立臺灣科技大學
電機工程系
95
This thesis is concerned with the design of three-phase expandable parallel multi-functional uninterruptible power supply (UPS) systems. The system communication is conducted by controller area network (CAN). When the AC mains is normal, the proposed system provides compensating reactive power using current-controlled mode. Whereas, if the AC mains fails, the system will supply the battery power to the load with master/slave control. The master UPS operates under voltage-controlled mode, while all the other converters function under current-controlled mode. If the UPS under voltage-controlled mode fails, one of the UPS under current-controlled mode will be changed to voltage-controlled mode to provide stable AC voltage. Thus, each UPS can either provide AC voltage source independently, or be connected with others in parallel for capacity expansion. The control scheme of the system is implemented by a 16-bit digital signal processor to reduce the hardware components. The experimental results for 1030 W linear resistive load show that the total harmonic distortion of output voltage is 1.32 %. Each UPS can share current and output power evenly.
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Chang, Hsiu Wei, and 張修維. "Design and Implementation of Rotary-Type Three-Phase Uninterruptible Power Supply Systems." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/51100769214788849609.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
96
This thesis is concerned with the design and implementation of rotary-type, three-phase uninterruptible power supply (UPS) systems. In this system, a permanent-magnet synchronous motor is used to drive an excited-type synchronous generator to generate three-phase electrical power to loads. The full-bridge diode rectifier is used to convert the utility to dc source for inverter to drive the permanent-magnet synchronous motor. Besides, batteries can release energy when utility fails to assure the supply of dc source voltage. The current control method of synchronous frame with closed-loop speed control mechanism is used to maintain constant motor speed. On the other hand, the dc chopper in accordance with the feedback of three-phase voltage is designed to adjust the exciting current for synchronous generator, and thereby outputs the three-phase electrical power with constant-voltage and constant-frequency. A high-performance, low-cost, 16-bit digital signal processor (DSP, TMS320LF2407A) is used as the control core. The control of motor and inverter is accomplished by software for reducing the circuit complexity. A prototype of 600W synchronous motor with speed control system is developed. Finally, experiments are given to justify the feasibility of the proposed system.
49
Yang, Jiou-Meng, and 楊久孟. "Development of Three-Phase Parallel Uninterruptible Power Supply Systems with the Function of Reactive Power Compensator." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/53614840266661310485.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
93
This thesis is concerned with the implementation of three-phase parallel multi-functional uninterruptible power supply systems. The system consists of two three-phase three-leg parallel converters. When the AC mains is normal, the proposed system regulates its output current according to the AC load, and achieves compensating reactive power, reducing voltage regulation and charging battery. If the AC mains fails, the system will supply the battery power to the load with master/slave control. The first dc-to-ac power converter with double control loops provides stable AC voltage source with low harmonic distortion, whereas the second converter operates under current-controlled mode to provide harmonic compensation current or share load current based on different loads to improve system capacity. As to the management of batteries, the charging/discharging schemes are fulfilled by a boost/buck DC chopper. The performance of the system is first simulated with MATLAB/Simulink. The control scheme of the system is implemented by a 16-bit digital signal processor (DSP, TMS320LF2407A) to reduce the hardware components. The experimental results for 1380 W linear resitive load and 1030 W nonlinear load show that the total harmonic distortions of output voltage are 1.4 % and 5.5 %, respectively. Besides, the proposed system can yield power compensation for the inductive load of 630 W and 640 VAR under normal utility operation. Experimental and simulated data are given to justify the analysis.
50
Li, Yu-wei, and 李昱葳. "Photovoltaic Power Supply System with Three-stage Energy Management and Maximum Power Point Tracking under Partially Shaded Conditions." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/41135901828485335429.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
100
In recent years, because environmental pollution and fossil energy will be run out soon, renewable energies are becoming the focus of the development worldwide. Among them, solar energy is the most attractive. The advantages of the solar energy are quiet, clean and inexhaustible. This thesis aims to study and implement a photovoltaic power supply system with three-stage energy management and maximum power point tracking (MPPT) capability under partially shaded conditions. The three-stage energy management can increase the utilization of solar panels, and raise system stability. A modified P&O MPPT method is also realized to overcome the problems due to solar shading effect. The operating principles and design considerations of the studied photovoltaic system are analyzed and discussed in details. A 2-kW laboratory prototype was implemented and tested. The experimental results are shown to verify the feasibility of the proposed scheme.