Дисертації з теми "Unbalanced mode"
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Hartono, Aryudha. "Microgrid Safety and Protection Strategies." Thesis, KTH, Elektroteknisk teori och konstruktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-226593.
Повний текст джерелаEtt problem som finns med microgrid är att de distribuerade produktionsgeneratorerna harett dubbelriktat effektflöde som modifierar felströmmen. Dessutom, inverterbaseradeförnyelsebara energikällor (IB-RES) begränsar det totala felströmsbidraget på grund av desstermiska kapacitet. Eftersom microgrids ska vara operativ vid både anslutning till externt nätsamt önätsdrift behövs skyddsstrategier för att kunna hantera fel, speciellt vid önätsdrift.Om endast IB-RES och batterilager används kan feldrift och normal drift inte särskiljas.Bortsätt från felhantering är det viktigt att studera felbortkoppling för microgrid underbegränsad felström som fås av IB-RES. För att kunna åstadkomma felbortkoppling behöveren IED (från engelskans Intelligent Electronic Device). Det första steget är att finna en metodför att kunna detektera fel under fel nivå modifiering. Denna avhandling tittar på att användanoll- och minusföljds ström sekvensskydd för att detektera fel. För att göra skyddet selektivtkommer det att titta på riktningen av effektflödet. I distributionsnät är det vanligt att haobalanserade laster vilket medför noll- och negativa sekvenskomponenter i nätet. För atttillämpa riktningsskydd för noll och negativ sekvens ström simuleras ett obalanserateffektflöde för att särskilja på feldrift och normal drift vid obalanserad last.Säkerhet och förordningar diskuteras kortfattat i denna avhandling. Det är viktigt att varjeIB-RES har en feltålighet som följer vissa förordningar. Denna förordning förväntassamordna det föreslagna skyddet i micronåt så att pålitlighet, selektivitet och känslighet kanåstadkommas vid nätanslutning och önätsdrift. Denna avhandling visar samordningen mellansäkringar, IED och feltåligheten för växelomriktare.Anpassningsförmågan för det föreslagna skyddet bedöms med avseende på expansion avmicrogrid. Resultatet visar att en expansion av ett microgrid inte kommer att störa denföreslagna samordningen om skyddsmetoden och tidsfördröjningskravet som presenteras idenna avhandling följs. Eftersom det är känt att distributionsnätet kommer att fortsätta ökasin lastkapacitet och mikrogenerering, är det lämpligt att skyddet förväntas varaanpassningsbart vilket innebär att det har en fast IED inställning när nätet expanderas.Analysen genomförs med mjukvarorna electrical transient analysis program (ETAP) ochMatlab Simulink. Kortslutningsanalysen, arbetssekvensen och obalanserad lastflödesimuleras av ETAP, medan skyddsstabiliteten simuleras av Matlab Simulink.
Kazem, Hussein A. "Development and analysis of supply side rectifier circuits model under balanced & unbalanced supply conditions." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506526.
Повний текст джерелаСиротин, 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.
Повний текст джерелаThesis 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).
Phan, Anh Tuan. "Power Systems Model Developments for Power Qality Monitoring : Application to Fundamental Frequency and Unbalance Estimation." Thesis, Mulhouse, 2016. http://www.theses.fr/2016MULH8692/document.
Повний текст джерелаRenewable energy, electricity and smart grids are core subjects as they have great environmental and societal impacts. Thus, generating, transporting and managing electric energy, i.e., power, still continue to drive a growing interest. In order to properly achieve these goals, several locks must be removed. Beyond issues related to the distribution architecture, the formalization of models, sizing tools, features and indicators, constraints and criteria, decentralized generation and energy management, power quality is central for the whole grid’s reliability. Disturbances affect the power quality and can cause serious impact on other equipment connected to the grid. The work of this thesis is part of this context and focuses on the development of models, indicators, and signal processing methods for power quality monitoring in time-varying power distribution systems.This thesis analyzes the power quality including several well-known features and their relevance. Power system models and signal processing methods for estimating their parameters are investigated for the purpose of real-time monitoring, diagnostic and control tasks under various operating conditions. Among all, the fundamental frequency is one of the most important parameters of a power distribution system. Indeed, its value which is supposed to be a constant varies continuously and reflects the dynamic availability of electric power. The fundamental frequency can also be affected by renewable energy generation and by nasty synchronization of some devices. Moreover, the power absorbed by loads or produced by sources is generally different from one phase to the other one. Obviously, most of the existing residential and industrial electrical installations with several phases work under unbalanced conditions. Identifying the symmetrical components is therefore an efficient way to quantify the imbalance between the phases of a grid. New state-space representations of power systems are proposed for estimating the fundamental frequency and for identifying the voltage symmetrical components of unbalanced three-phase power systems. A first state-space representation is developed by supposing the fundamental frequency to be known or to be calculated by another estimator. In return, it provides other parameters and characteristics from the power system. Another original state-space model is introduced which does not require the fundamental frequency. Here, one state variable is a function of the frequency which can thus be deduced. Furthermore this new state-space model is perfectly are able to represent a three-phase power system in both balanced and unbalanced conditions. This not the case of lots of existing models. The advantage of the proposed state-space representation is that it gives directly access to physical parameters of the system, like the frequency and the amplitude and phase values of the voltage symmetrical components. Power systems parameters can thus be estimated in real-time by using the new state-space with an online estimation process like an Extended Kalman Filter (EKF). The digital implementation of the proposed methods presents small computational requirement, elegant recursive properties, and optimal estimations with Gaussian error statistics.The methods have been implemented and validated through various tests respecting real technical constraints and operating conditions. The methods can be integrated in active power filtering schemes or load-frequency control strategies to monitor power systems and to compensate for electrical disturbances
Shan, Liang. "Joint Gaussian Graphical Model for multi-class and multi-level data." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/81412.
Повний текст джерелаPh. D.
Pham, Hai Minh. "Computation of the vibration of a whole aero-engine model with nonlinear bearings." Thesis, University of Manchester, 2010. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:128171.
Повний текст джерелаWang, Shuo. "Characterization and Cancellation of High-Frequency Parasitics for EMI Filters and Noise Separators in Power Electronics Applications." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/27885.
Повний текст джерелаPh. D.
Junior, Edson Luis Geraldi. "Parameter estimation for a three-phase distributed synchronous generator model using noisy measurements." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-19102018-143704/.
Повний текст джерелаOs modelos simplificados de geradores síncronos, amplamente utilizados em estudos de estabilidade de grandes sistemas elétricos de potência, não são completamente adequados para a análise de estabilidade e projetos de controladores dos geradores síncronos distribuídos, geralmente conectados a sistemas tipicamente desequilibrados. Para que os sistemas com geração distribuída possam ser analisados mais fidedignamente, é necessária a utilização de um modelo de gerador síncrono que considere a variação de frequência em suas equações elétricas. Além disso, esse modelo também deve ser capaz de representar possíveis tensões trifásicas desequilibradas nos terminais do gerador. Entretanto, para que esse modelo mais detalhado possa fornecer respostas coerentes com a realidade, deve-se conhecer seus parâmetros. Dessa forma, este trabalho avalia a influência dos parâmetros nas respostas de um modelo de gerador síncrono mais detalhado, adequado para representar operações desbalanceadas, e propõe uma abordagem para a estimação de seus parâmetros mais importantes. Nessa estrutura, inicialmente empregam-se as Funções de Sensibilidade de Trajetória para avaliar a dependência das respostas desse modelo em relação aos seus parâmetros e, a partir disso, ordená-los conforme sua importância. Em seguida, aplica-se um processo de estimação que utiliza o Filtro de Kalman Unscented com o auxílio de um algoritmo genético para estimar os principais parâmetros desse modelo de gerador síncrono em condições de desbalanço. Para a obtenção dos resultados e consequente avaliação da abordagem de estimação proposta, utiliza-se um sistema composto por um gerador síncrono conectado a uma carga trifásica desbalanceada. Além da operação desbalanceada desse sistema teste, também são considerados ruídos devidos ao constante chaveamento de cargas, típicos de sistemas de distribuição. As estimações realizadas para três condições de operação do gerador foram bem satisfatórias, indicando a eficiência da abordagem proposta na obtenção de modelos adequados para descrever a operação de geradores síncronos em condições de desbalanço.
Alkhatib, Rami. "Human locomotion analysis, classification and modeling of normal and pathological vertical ground reaction force signals in elderly." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSES029/document.
Повний текст джерелаWalking is defined as sequences of repetitive cyclic gestures. It was already shown that the speed and the variability of these sequences can reveal abilities or motorskill failures. The originality of this work is to analyze and characterize the steps of elderly persons by using pressure signals. In a preliminary study, we showed that pressure signals are characterized by cyclostationarity. In this study, we intend to exploit the nonstationarity of the signals in a search for new indicators that can help in gait signal classification between normal and Parkinson subjects in the elderly population. These parameters are tested on a population of 47 subjects. First, we started with preprocessing the vertical ground reaction force (VGRF) signals and showed in this first part of the thesis that filtering can remove a vital part of the signal. That is why an adaptive filter based on empirical mode decomposition (EMD) was built. Turning points are filtered using synochronosqueezing of time-frequency representations of the signal. We also showed that the content of gait force signals is highly affected by unquantifiable parameter such as cognitive tasks which make them hard to be normalized. That is why features being extracted are derived from inter-subject comparison. For example we equated the difference in the load distribution between feet. It is also recommended in this work to choose the mid-sensor rather than relying on summation of forces from array of sensors for classification purposes. A hypothesis of balanced and unbalanced gait is verified to be potential in improving the classification accuracy. The power of this hypothesis is shown by using the load distribution and Age×Speed in the first classifier and the correlation in the second classifier. A time series simulation of VGRF based on a modified version of nonstationary- Markov model of first order is derived. This model successfully predict gaits in normal subjects and fairly did in Parkinson’s gait. We found out that the three modes: time, frequency and space are helpful in analyzing force signals that is why parallel factor analysis is introduced as a tensor method to be used in a future work
Gao, Zhi. "Sensorless Stator Winding Temperature Estimation for Induction Machines." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/13966.
Повний текст джерелаJakel, Roland. "Linear Dynamic System Analyses with Creo Simulate – Theory & Application Examples, Capabilities, Limitations –." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-225992.
Повний текст джерела1. Introduction to dynamic analysis theory in Creo Simulate 2. Modal analysis (standard and with prestress) 3. Dynamic analysis, including analysis classification, some simple examples for own self-studies (shaft under unbalance excitation and a one-mass-oscillator) and several real-world examples of bigger dynamic systems 4. Feedback to the software developer PTC (enhancement requests and code issues) 5. References
Chen, Wendy, and 陳嘉萍. "Balanced-unbalanced Transformer Design and Enhancement-depletion mode Voltage Control Oscillator Design." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/94186794081781754357.
Повний текст джерелаHayes, Philip Doyle Cunningham Philip. "Balanced and unbalanced flow in primitive eqaution model simulations of baroclinic wave life cycles." Diss., 2005. http://etd.lib.fsu.edu/theses/available/etd-04112005-121604.
Повний текст джерелаAdvisor: Dr. Philip Cunningham, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed June 7, 2005). Document formatted into pages; contains xiv, 118 pages. Includes bibliographical references.
Hung, Yu-Yan, and 洪于硯. "The power and sample size calculation for one-way random effects model - The Unbalanced Case." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/6w2t6w.
Повний текст джерела國立交通大學
管理科學系所
101
In the experimental design, sample size plays an important role in experimental reliability and confidence level. Under the constraints of costs and available resources, how can we determine the optimal sample size required to estimate characteristics of the population? In this research, we want to measure the power of intraclass correlation coefficient for the unbalanced case in the random effects model.
Ghimire, Narishwar. "Evaluating Water Transfers in Irrigation Districts." Thesis, 2013. http://hdl.handle.net/1969.1/149537.
Повний текст джерелаChen, Chih Pei, and 陳治霈. "Unbalance dynamic model exploring and vibration improvement in a high-speed precision punch." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/24535085369505039049.
Повний текст джерела明志科技大學
電機工程系碩士班
103
echanical crank presses in operation, the quality of the internal mechanism of Newton's second law of motion due to the inertia force generated on the rack, resulting in an imbalance of the machine, causing vibration punch when punching machines are more likely to cause life shortening . The conventional way to solve the dynamic imbalance punch, often with the addition of the slider balancing mechanism as a four-bar linkage group. Study purpose of this paper is to analyze the vibration generated by high-speed precision punch in the course of, and improve the machine vibration in the course of such value to enhance the punch. High-speed precision punching of the first crank provides manufacturers inertia force is derived in order to understand the operation of the power division of the punch of the process, and then use the lever weight and center of mass and other parameters of the slider do inertia cases and compared. Finally, the inertia force is derived as boundary conditions of numerical analysis and calculation method. In this paper, using numerical analysis method to analyze the calculation method can be used to calculate the numerical analysis computer software simulation, analysis software, ANSYS Workbench and so on through the finite elements, the present study first to draw the entire physical infrastructure software for frame part, using finite element Analysis ANSYS Workbench software for analysis, and the use of the inertial forces derived derived inertial force and the lateral thrust as boundary conditions to analyze, but to observe and analyze the results and the improvement of structural analysis results after comparison, to identify the partial structure The improvement programs can be used as a reference for future design improvements when.
Yi-Na, Chiang, and 江宜娜. "A System Dynamics Model of Education System in Taiwan--Unbalance between Supply & Demand of Teacher." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/40854842100037527251.
Повний текст джерела大葉大學
事業經營研究所
92
Facing the phenomenon that teacher job vacancies are difficult to recruited, and many senior teachers are waiting to retired. This study view unemployed problems of “vagabond teacher” as an education government management range, and the quality of teacher also is an important loop in the education system. Therefore, we focus on unbalanced problems between teacher supply and demand. We use whole system viewpoint study education system structure, and build teacher supply and demand system dynamics model to find out fluctuate sources in education system. In order to observe education develop process in education system model, we divide education system to three subsystems. First, the science subsystem, second, the education policy and third is economic subsystem. Through the reality simulation, we can find the changed patterns of three variables, they are vagabond teacher, teacher quality and teacher supply and demand. Finally, we use policy-test methods to find out the best policies and then improve the system behavior. To avoid single policy to obstruct whole system long term develop make system bring out “fixes that fail” behavior.
Hsu, Chun Hao, and 許淳皓. "Dynamical Performance Enhancement of Isolated Power Converters under Unbalanced and Nonlinear Load Conditions by Combining Model Predictive Control and Repetitive Control." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/17225414432756147992.
Повний текст джерела國立清華大學
電機工程學系
104
Under the isolated microgrid, the output voltage of the inverter is influenced by different load conditions; further, the unbalanced load and the nonlinear load affect the output voltage of the inverter significantly. In order to mitigate voltage unbalance rate and improve total harmonic distortion (THD) caused by the unbalanced loads under the existing converter structure, this thesis not only applies model predictive control on inner current control loop to improve the dynamic response, but also performs the repetitive control on the outer loop to improve THD. Besides, the discrete model for analyzing effect of the predictive controller and repetitive controller are constructed to prove the stability of the system. The proposed control strategy is performed by Simulink; moreover, the presented theory are also verified by different simulations such as unbalanced loads, nonlinear loads and switching loads.
Huang, Yunkai. "Non-global regression modelling." Thesis, 2016. http://hdl.handle.net/1828/7346.
Повний текст джерелаGraduate
SHEU, RUEY-LONG, and 許瑞龍. "Experimental study of a two-dimension perturbation and observation algorithm for improving the unbalanced operation of a three-phase induction machine in motor and generator modes." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/qj49su.
Повний текст джерела國立雲林科技大學
工程科技研究所
104
To address the voltage unbalance issues of the single-phase powered three-phase induction motor and the three-phase self-excited induction generator supplying single-phase loads, a novel balancing scheme with PC-based control called the two-dimensional perturbation and observation method is proposed and implemented. In the first part, the balancing scheme is composed of two static Var compensators (SVCs) in Steinmetz connection, and is modeled and analyzed by the positive- and negative-sequence equivalent circuits of the three-phase induction motor. The steady-state analysis allows the proper values of the energy-storage elements that balance the motor to be found. Simulations using the EMTP have shown that the motor can be balanced from starting to full load by adjusting the SVCs' firing angles. In the second part, the induction motor is operated as a self-excited induction generator. Appropriate control of the SVC firing angles also allows the single-phase loaded generator to work in a balance condition. Finally, a practical 0.5 HP cage induction motor with SVCs is used in the motor mode and the generator mode to test the PC-based control interface. The testing results indicate that the experimental results are in very good agreement with the simulation results, which demonstrates that the proposed PC-based control interface is feasible and can have more future applications.
Costa, Sofia Moura da. "Baumol’s cost disease in the health care sector." Master's thesis, 2019. http://hdl.handle.net/10400.14/29040.
Повний текст джерелаO impacto do aumento dos custos na despesa pública e privada relativos ao Sector da Saúde tem sido motivo de preocupação, uma vez que estes afetam a estabilidade financeira do país. Assim, foram estudados vários fatores influenciadores dos gastos associados ao sector da Saúde. De acordo com os resultados obtidos, a doença de custos de Baumol foi um dos fatores com maior impacto no crescimento dos referidos custos. Baumol (1967) define a doença dos custos como sendo a diferença entre o crescimento dos salários na Economia e o crescimento da produtividade no sector dos serviços, como é o caso do sector da saúde. Portanto, esta diferença faz com que os custos unitários no sector de saúde aumentem ao longo do tempo. Esta tese estuda o impacto da doença dos custos de Baumol no sector da Saúde com o intuito de compreender se existe espaço suficiente para a introdução de políticas eficazes na contenção do aumento dos custos associados a este sector. Portanto, foi definido um instrumento – variável de Baumol ajustada – para medir a doença de custos de Baumol e, posteriormente, foi aplicada com um conjunto de dados em painel, contendo 18 países membros da OCDE de 1970 a 2016. Os resultados encontrados mostram que a referida variável explica entre 20% a 80% do aumento dos gastos com a saúde dependendo da definição do sector de Baumol. Conclui-se que existe margem para implementar políticas pois o aumento das de saúde não é totalmente explicado pela doença dos custos de Baumol.