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1
Axelberg, Peter. "On Tracing Flicker Sources and Classification of Voltage Disturbances." Doctoral thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3416.
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Developments in measurement technology, communication and data storage have resulted in measurement systems that produce large amount of data. Together with the long existing need for characterizing the performance of the power system this has resulted in demand for automatic and efficient information-extraction methods. The objective of the research work presented in this thesis was therefore to develop new robust methods that extract additional information from voltage and current measurements in power systems. This work has contributed to two specific areas of interest.The first part of the work has been the development of a measurement method that gives information how voltage flicker propagates (with respect to a monitoring point) and how to trace a flicker source. As part of this work the quantity of flicker power has been defined and integrated in a perceptionally relevant measurement method. The method has been validated by theoretical analysis, by simulations, and by two field tests (at low-voltage and at 130-kV level) with results that matched the theory. The conclusion of this part of the work is that flicker power can be used for efficient tracing of a flicker source and to determine how flicker propagates.The second part of the work has been the development of a voltage disturbance classification system based on the statistical learning theory-based Support Vector Machine method. The classification system shows always high classification accuracy when training data and test data originate from the same source. High classification accuracy is also obtained when training data originate from one power network and test data from another. The classification system shows, however, lower performance when training data is synthetic and test data originate from real power networks. It was concluded that it is possible to develop a classification system based on the Support Vector Machine method with “global settings” that can be used at any location without the need to retrain. The conclusion is that the proposed classification system works well and shows sufficiently high classification accuracy when trained on data that originate from real disturbances. However, more research activities are needed in order to generate synthetic data that have statistical characteristics close enough to real disturbances to replace actual recordings as training data.
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Looja, Tuladhar R. "Control of Custom Power System using Active Disturbance Rejection Control." Cleveland State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=csu1438913443.
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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.
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Les énergies renouvelables, l’énergie sous la forme électrique et son transport à l’aide de réseaux électriques intelligents représentent aujourd’hui des enjeux majeurs car ils ont de grands impacts environnementaux et sociétaux. Ainsi, la production, le transport et la gestion de l’énergie électrique, continuent toujours à susciter un intérêt croissant. Pour atteindre ces objectifs, plusieurs verrous technologiques doivent être levés. Au-delà des questions liées aux architectures des réseaux électriques, aux modèles, aux outils de dimensionnement, à la formalisation de caractéristiques et d’indicateurs, aux contraintes et aux critères, à la gestion et à la production décentralisée, la qualité de la puissance électrique est centrale pour la fiabilité de l’ensemble du système de distribution. Les perturbations affectent la qualité des signaux électriques et peuvent provoquer des conséquences graves sur les autres équipements connectés au réseau. Les travaux de cette thèse s’inscrivent dans ce contexte et de fait ils sont orientés vers le développement de modèles, d’indicateurs et de méthodes de traitement des signaux dédiés à la surveillance en temps-réel des performances des réseaux de distribution électrique.Cette thèse analyse la qualité de la puissance électrique, en prenant en compte plusieurs caractéristiques bien connues ainsi que leur pertinence. Les modèles des systèmes électriques et les méthodes de traitement du signal pour estimer leurs paramètres sont étudiés pour des applications en temps-réel de surveillance, de diagnostic et de contrôle sous diverses conditions. Parmi tous, la fréquence fondamentale est l’un des paramètres les plus importants pour caractériser un système de distribution électrique. En effet, sa valeur qui est censée être une constante, varie en permanence et reflète la dynamique de l’énergie électrique disponible. La fréquence peut également être affectée par certaines productions d’énergie renouvelable et peut être influencée par des mauvaises synchronisations de certains équipements. En outre, la puissance absorbée par les charges ou produite par des sources est généralement différente d’une phase à l’autre. Évidemment, la plupart des installations électriques existantes avec plusieurs phases, qu’elles soient résidentielles ou industrielles, travaillent dans des conditions déséquilibrées. Identifier les composantes symétriques de tension est dans ce cas un moyen pertinent pour quantifier le déséquilibre entre les phases d’un système électrique.De nouvelles représentations de type espace d’état et modélisant des systèmes électriques sont proposées pour estimer la fréquence fondamentale et pour identifier les composantes symétriques de tension des systèmes électriques triphasés et déséquilibrés. Le premier modèle d’espace d’état proposé considère la fréquence fondamentale comme connue ou obtenue par un autre estimateur. En contrepartie, il fournit les autres paramètres caractérisant le système électrique. Un second modèle d’état-espace est introduit. Il est original dans le sens où il ne nécessite aucune connaissance de la fréquence fondamentale. Une de ses variables d’état est directement reliée à la fréquence et permet donc de la déduire. En outre, ce nouvel espace d’état est parfaitement capable de représenter des systèmes électriques à trois phases équilibrés et non équilibrés. [...]Renewable 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
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Barrera, Núñez Víctor Augusto. "Automatic diagnosis of voltage disturbances in power distribution networks." Doctoral thesis, Universitat de Girona, 2012. http://hdl.handle.net/10803/80944.
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This thesis proposes a framework for identifying the root-cause of a voltage disturbance, as well as, its source location (upstream/downstream) from the monitoring place. The framework works with three-phase voltage and current waveforms collected in radial distribution networks without distributed generation. Real-world and synthetic waveforms are used to test it. The framework involves features that are conceived based on electrical principles, and assuming some hypothesis on the analyzed phenomena. Features considered are based on waveforms and timestamp information. Multivariate analysis of variance and rule induction algorithms are applied to assess the amount of meaningful information explained by each feature, according to the root-cause of the disturbance and its source location. The obtained classification rates show that the proposed framework could be used for automatic diagnosis of voltage disturbances collected in radial distribution networks. Furthermore, the diagnostic results can be subsequently used for supporting power network operation, maintenance and planning.En esta tesis se propone una metodología para la identificación de la localización relativa (aguas arriba/abajo) y la causa de una perturbación eléctrica. La metodología utiliza las ondas trifásicas de tensión y de corriente registradas en redes de distribución radial sin presencia de generación distribuida. La metodología es validada utilizando perturbaciones eléctricas reales y simuladas. La metodología involucra atributos que han sido concebidos basándose en principios eléctricos e hipótesis de acuerdo a cada uno de los fenómenos eléctricos analizados. Se propusieron atributos tanto basados en la forma de onda como en la fecha de ocurrencia de la perturbación. La cantidad de información contenida y/o explicada por cada atributo es valorada mediante la aplicación del análisis multivariante de la varianza y algoritmos de extracción automática de reglas de decisión. Los resultados de clasificación muestran que la metodología propuesta puede ser utilizada para el diagnóstico automático de perturbaciones eléctricas registradas en redes de distribución radial. Los resultados de diagnóstico pueden ser utilizados para apoyar las tareas de operación, mantenimiento y planeamiento de las redes de distribución.
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Parsons, Antony Cozart. "Automatic location of transient power quality disturbances /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Littler, Timothy Brian. "Wavelets for the analysis and compression of power system disturbances." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263403.
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Tamronglak, Surachet. "Analysis of power system disturbances due to relay hidden failures." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/39136.
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This research analyzes the linkage between power system disturbances and
failures in relaying systems. The annual disturbance reports prepared by the North
American Electric Reliability Council were examined. It has been found that
relaying system failures plays very important role in power system cascading
outages. The type of relaying system failures that are the most troublesome are the
ones that have a potential to remain hidden until being exposed by some abnormal
power system states to trigger relay misoperations.
Each commonly used relaying scheme in transmission system is examined
for any hidden failures that can lead to relay misoperations and multiple power
system contingencies. Each hidden failure mode has a region, called region of
vulnerability. Inside this region, some abnormal power system states can expose
the hidden failure. The reach of the region depends largely on the settings of the
relay in question.
A method of computing the relative importance of each region of
vulnerability, called vulnerability index, was proposed. The calculation of the
index can be based on some measurements of power system performances. In this
research, the stability measurements of the system following some contingencies
that may occur in the region are chosen. With this approach, vulnerable relays can
be identified.
A preventive method was proposed so that the number of relay
misoperations due to hidden failures and, ultimately, the number of power system
disturbances can be reduced.Ph. D.
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Fletcher, Robert Henry. "Optimal distribution system horizon planning /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/6018.
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Yu, Xuebei. "Distribution system reliability enhancement." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41091.
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Practically all everyday life tasks from economic transactions to entertainment depend on the availability of electricity. Some customers have come to expect a higher level of power quality and availability from their electric utility. Federal and state standards are now mandated for power service quality and utilities may be penalized if the number of interruptions exceeds the mandated standards. In order to meet the requirement for safety, reliability and quality of supply in distribution system, adaptive relaying and optimal network reconfiguration are proposed. By optimizing the system to be better prepared to handle a fault, the end result will be that in the event of a fault, the minimum number of customers will be affected. Thus reliability will increase.
The main function of power system protection is to detect and remove the faulted parts as fast and as selectively as possible. The problem of coordinating protective relays in electric power systems consists of selecting suitable settings such that their fundamental protective function is met under the requirements of sensitivity, selectivity, reliability, and speed. In the proposed adaptive relaying approach, weather data will be incorporated as follows. By using real-time weather information, the potential area that might be affected by the severe weather will be determined. An algorithm is proposed for adaptive optimal relay setting (relays will optimally react to a potential fault). Different types of relays (and relay functions) and fuses will be considered in this optimization problem as well as their coordination with others. The proposed optimization method is based on mixed integer programming that will provide the optimal relay settings including pickup current, time dial setting, and different relay functions and so on.
The main function of optimal network reconfiguration is to maximize the power supply using existing breakers and switches in the system. The ability to quickly and flexibly reconfigure the power system of an interconnected network of feeders is a key component of Smart Grid. New technologies are being injected into the distribution systems such as advanced metering, distribution automation, distribution generation and distributed storage. With these new technologies, the optimal network reconfiguration becomes more complicated. The proposed algorithms will be implemented and demonstrated on a realistic test system. The end result will be improved reliability. The improvements will be quantified with reliability indexes such as SAIDI.
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Rosado, Sebastian Pedro. "Analysis of Electric Disturbances from the Static Frequency Converter of a Pumped Storage Station." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34448.
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The present work studies the disturbances created in the electric system of a pumped storage power plant, which is an hydraulic generation facility where the machines can work as turbines or pumps, by the operation of a static frequency converter (SFC). The SFC is used for starting the synchronous machines at the station when in the pump mode. During the starting process several equipment is connected to the SFC being possible to get affected by the disturbances generated. These disturbances mainly include the creation of transient overvoltages during the commutation of the semiconductor devices of the SFC and the introduction of harmonics in the network currents and voltages. This work analyzes the possible effects of the SFC operation over the station equipment based on computer simulations. For this purpose, the complete system was modeled and the starting process simulated in a computer transient simulator program. The work begins with a general review of the effects of electric disturbances over high voltage equipment and in particular of the disturbances generated by power electronics conversion equipment. Then the models for the different kind of equipment present in the system are discussed and formulated. The control system that governs the operation of the SFC during the starting process is analyzed later as well as the operation conditions. Once the model of the system is set up, the harmonic analysis of the electric network is done by frequency domain and time domain methods. Time domain methods are also employed for the analysis of the commutation transient produced by the SFC operation. Finally, the simulation results are used to evaluate the impact of the SFC operation on the station equipment, especially on the generator step up transformer.Master of Science
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Etminan, S. "Simulation of high-speed static reactive compensation for suppression of power system disturbances." Thesis, University of Sunderland, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253748.
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Rivas-Davalos, Francisco. "A genetic algorithm for power distribution system planning." Thesis, Brunel University, 2004. http://bura.brunel.ac.uk/handle/2438/7891.
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The planning of distribution systems consists in determining the optimum site and size of new substations and feeders in order to satisfy the future power demand with minimum investment and operational costs and an acceptable level of reliability. This problem is a combinatorial, non-linear and constrained optimization problem. Several solution methods based on genetic algorithms have been reported in the literature; however, some of these methods have been reported with applications to small systems while others have long solution time. In addition, the vast majority of the developed methods handle planning problems simplifying them as single-objective problems but, there are some planning aspects that can not be combined into a single scalar objective; therefore, they require to be treated separately. The cause of these shortcomings is the poor representation of the potential solutions and their genetic operators This thesis presents the design of a genetic algorithm using a direct representation technique and specialized genetic operators for power distribution system expansion planning problems. These operators effectively preserve and exploit critical configurations that contribute to the optimization of the objective function. The constraints of the problems are efficiently handle with new strategies. The genetic algorithm was tested on several theoretical and real large-scale power distribution systems. Problems of network reconfiguration for loss reduction were also included in order to show the potential of the algorithm to resolve operational problems. Both single-objective and multi-objective formulations were considered in the tests. The results were compared with results from other heuristic methods such as ant colony system algorithms, evolutionary programming, differential evolution and other genetic algorithms reported in the literature. From these comparisons it was concluded that the proposed genetic algorithm is suitable to resolve problems of largescale power distribution system planning. Moreover, the algorithm proved to be effective, efficient and robust with better performance than other previous methods.
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Ibrahim, Sarmad Khaleel. "DISTRIBUTION SYSTEM OPTIMIZATION WITH INTEGRATED DISTRIBUTED GENERATION." UKnowledge, 2018. https://uknowledge.uky.edu/ece_etds/116.
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In this dissertation, several volt-var optimization methods have been proposed to improve the expected performance of the distribution system using distributed renewable energy sources and conventional volt-var control equipment: photovoltaic inverter reactive power control for chance-constrained distribution system performance optimisation, integrated distribution system optimization using a chance-constrained formulation, integrated control of distribution system equipment and distributed generation inverters, and coordination of PV inverters and voltage regulators considering generation correlation and voltage quality constraints for loss minimization. Distributed generation sources (DGs) have important benefits, including the use of renewable resources, increased customer participation, and decreased losses. However, as the penetration level of DGs increases, the technical challenges of integrating these resources into the power system increase as well. One such challenge is the rapid variation of voltages along distribution feeders in response to DG output fluctuations, and the traditional volt-var control equipment and inverter-based DG can be used to address this challenge.
These methods aim to achieve an optimal expected performance with respect to the figure of merit of interest to the distribution system operator while maintaining appropriate system voltage magnitudes and considering the uncertainty of DG power injections. The first method is used to optimize only the reactive power output of DGs to improve system performance (e.g., operating profit) and compensate for variations in active power injection while maintaining appropriate system voltage magnitudes and considering the uncertainty of DG power injections over the interval of interest. The second method proposes an integrated volt-var control based on a control action ahead of time to find the optimal voltage regulation tap settings and inverter reactive control parameters to improve the expected system performance (e.g., operating profit) while keeping the voltages across the system within specified ranges and considering the uncertainty of DG power injections over the interval of interest. In the third method, an integrated control strategy is formulated for the coordinated control of both distribution system equipment and inverter-based DG. This control strategy combines the use of inverter reactive power capability with the operation of voltage regulators to improve the expected value of the desired figure of merit (e.g., system losses) while maintaining appropriate system voltage magnitudes. The fourth method proposes a coordinated control strategy of voltage and reactive power control equipment to improve the expected system performance (e.g., system losses and voltage profiles) while considering the spatial correlation among the DGs and keeping voltage magnitudes within permissible limits, by formulating chance constraints on the voltage magnitude and considering the uncertainty of PV power injections over the interval of interest.
The proposed methods require infrequent communication with the distribution system operator and base their decisions on short-term forecasts (i.e., the first and second methods) and long-term forecasts (i.e., the third and fourth methods). The proposed methods achieve the best set of control actions for all voltage and reactive power control equipment to improve the expected value of the figure of merit proposed in this dissertation without violating any of the operating constraints. The proposed methods are validated using the IEEE 123-node radial distribution test feeder.
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Javanshir, Marjan. "DC distribution system for data center." Thesis, Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39344952.
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Elizondo, de la Garza David C. "Hidden Failures in Protection Systems and its Impact on Power System Wide-area Disturbances." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/31890.
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This document explores Hidden Failures in protection systems, which have been identified as key contributors in the degradation of Power System wide-area disturbances. The Hidden Failure Modes in which the protection
systems may fail to operate correctly and their consequences are identified in a theoretical approach. This theoretical side has its practical counterpart since a number of Hidden Failure Modes are found in real wide-area disturbances.
The original definition of Hidden Failure, which is a failure that remains undetected and is uncovered by another system event, is included as well as developments on Hidden Failure sequence of events and a methodology for Hidden Failure identification. This method is based on Protection Element Functionality Defects (PEFD), which are applicable to all the elements included in the protective chain. PEFD are classified in two main groups.
Primary and Back-up protection schemes applied for Generators, Buses, Transformers and Transmission Lines are analyzed. The abnormal Power System conditions that each Power System element may have are enumerated. A catalogue of the relays or relay systems, in charge of detecting and stopping the continuous presence of the abnormal conditions is developed. Relay families organize this catalogue. The relaying schemes for five Special Protection Systems are described.
Thirty-three Hidden Failures Modes are included based on the relaying implementation for Primary protection, Back-up protection and Special Protection Systems. These Hidden Failures Modes are based on PEFD-A. Hidden Failures related to PEFD-B are included in a general fashion.
Wide-area disturbances based on NERC reports are analyzed and Hidden Failures are identified employing the developed methodology. The mechanisms in the disturbances are summarized and are applicable to Primary protection, Back-up protection and Special Protection Systems.
Regions of Vulnerability and Areas of Consequence definitions are included and are identified for a Power System wide-area disturbance. For some protection schemes the term Condition of Vulnerability was developed.
Regions of Vulnerability and Areas of Consequence will bring the initial steps towards the problem solution. Further research directions are oriented towards the development of a computer-based tool to track the regions of vulnerability in real time.Master of Science
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Cartier, J. C. "Power quality analysis in a CC-130 Hercules aircraft power distribution system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/MQ44836.pdf.
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Duvnjak, Zarkovic Sanja. "Security of Electricity Supply in Power Distribution System : Optimization Algorithms for Reliability Centered Distribution System Planning." Licentiate thesis, KTH, Elektroteknisk teori och konstruktion, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-281813.
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The importance of electricity in everyday life and demands to improve the reliability of distribution systems force utilities to operate and plan their networks in a more secure and economical manner. With higher demands on reliability from both customers and regulators, a big pressure has been put on the security of electricity supply which is considered as a fundamental requirement for modern societies. Thus, efficient solutions for reliability and security of supply improvements are not just of increasing interest, but also have significant socio-economic relevance. Distribution system planning (DSP) is one of the major activities of distribution utilities to deal with reliability enhancement. This thesis deals with developing optimization algorithms, which aim is to min- imize customer interruption costs, and thus maximize the reliability of the system. This is implemented either by decreasing customer interruption duration, frequency of customer interruptions or both. The algorithms are applied on a single or multi- ple DSP problems. Mixed-integer programming has been used as an optimization approach. It has been shown that solving and optimizing each one of the DSP problems contributes greatly to the reliability improvement, but brings certain challenges. Moreover, applying algorithms on multiple and integrated DSP problems together leads to even bigger complexity and burdensome. However, going toward this inte- grated approach results in a more appropriate and realistic DSP model. The idea behind the optimization is to achieve balance between reliability and the means to achieve this reliability. It is a decision making process, i.e. a trade-off between physical and pricing dimension of security of supply.QC 20200925
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Manghat, Jaidev. "Simulation of power distribution management system using OMACS metamodel." Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/944.
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Chen, Linwei. "Distribution network supports for transmission system reactive power management." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/distribution-network-supports-for-transmission-system-reactive-power-management(abcc8197-fd85-478b-b91a-fd3d0b3220db).html.
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To mitigate high voltages in transmission systems with low demands, traditional solutions often consider the installation of reactive power compensators. The deployment and tuning of numbers of VAr compensators at various locations may not be cost-effective. This thesis presents an alternative method that utilises existing parallel transformers in distribution networks to provide reactive power supports for transmission systems under low demands. The operation of parallel transformers in small different tap positions, i.e. with staggered taps, can provide a means of absorbing reactive power. The aggregated reactive power absorption from many pairs of parallel transformers could be sufficient to provide voltage support to the upstream transmission network. Network capability studies have been carried out to investigate the reactive power absorption capability through the use of tap stagger. The studies are based on a real UK High Voltage distribution network, and the tap staggering technique has been applied to primary substation transformers. The results confirm that the tap staggering method has the potential to increase the reactive power demand drawn from the transmission grid. This thesis also presents an optimal control method for tap stagger to minimise the introduced network loss as well as the number of tap switching operations involved. A genetic algorithm (GA) based procedure has been developed to solve the optimisation problem. The GA method has been compared with two alternative solution approaches, i.e. the rule-based control scheme and the branch-and-bound algorithm. The results indicate that the GA method is superior to the other two approaches. The economic and technical impacts of the tap staggering technique on the transmission system has been studied. In the economic analysis, the associated costs of applying the tap staggering method have been investigated from the perspective of transmission system operator. The IEEE Reliability Test System has been used to carry out the studies, and the results have been compared with the installation of shunt reactors. In the technical studies, the dynamic impacts of tap staggering or reactor switching on transmission system voltages have been analysed. From the results, the tap staggering technique has more economic advantages than reactors and can reduce voltage damping as well as overshoots during the transient states.
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Men, Kun. "Long term voltage stability analysis for small disturbances." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2499.
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Ozel, Kerem. "Losses In Electric Distribution System." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607916/index.pdf.
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The purpose of this thesis is to examine the technical losses in Electric Distribution Systems, the sources of the losses, minimum levels of the losses, ways to decrease the losses and current applications in Turkey. The wrong and weak parts of the current applications are determined and emphasized. Ways to decrease losses in Distribution Systems are advised.
The energy resources in the world are decreasing rapidly. There is a rapid growth in consumption. It is a must to use existing resources in most efficient way because there is no unlimited energy source. Losses in the electric distribution systems are one of the most important subjects because the most of the technical losses in electric systems occur in the distribution systems.
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McDermott, Thomas E. "A Heuristic Nonlinear Constructive Method for Electric Power Distribution System Reconfiguration." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30447.
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The electric power distribution system usually operates a radial configuration, with tie switches between circuits to provide alternate feeds. The losses would be minimized if all switches were closed, but this is not done because it complicates the system's protection against overcurrents. Whenever a component fails, some of the switches must be operated to restore power to as many customers as possible. As loads vary with time, switch operations may reduce losses in the system. Both of these are applications for reconfiguration.
The problem is combinatorial, which precludes algorithms that guarantee a global optimum. Most existing reconfiguration algorithms fall into two categories. In the first, branch exchange, the system operates in a feasible radial configuration and the algorithm opens and closes candidate switches in pairs. In the second, loop cutting, the system is completely meshed and the algorithm opens candidate switches to reach a feasible radial configuration. Reconfiguration algorithms based on linearized transshipment, neural networks, heuristics, genetic algorithms, and simulated annealing have also been reported, but not widely used. These existing reconfiguration algorithms work with a simplified model of the power system, and they handle voltage and current constraints approximately, if at all.
The algorithm described here is a constructive method, using a full nonlinear power system model that accurately handles constraints. The system starts with all switches open and all failed components isolated. An optional network power flow provides a lower bound on the losses. Then the algorithm closes one switch at a time to minimize the increase in a merit figure, which is the real loss divided by the apparent load served. The merit figure increases with each switch closing. This principle, called discrete ascent optimal programming (DAOP), has been applied to other power system problems, including economic dispatch and phase balancing. For reconfiguration, the DAOP method's greedy nature is mitigated with a backtracking algorithm. Approximate screening formulas have also been developed for efficient use with partial load flow solutions. This method's main advantage is the accurate treatment of voltage and current constraints, including the effect of control action. One example taken from the literature shows how the DAOP-based algorithm can reach an optimal solution, while adjusting line voltage regulators to satisfy the voltage constraints.Ph. D.
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Ratanapanachote, Somnida. "Applications of an electronic transformer in a power distribution system." Texas A&M University, 2004. http://hdl.handle.net/1969.1/2756.
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In electrical power distribution and power electronic applications, a transformer is an indispensable component which performs many functions. At its operating frequency (60/50 Hz), it is one of the most bulky and expensive components. The concept of the electronic transformer introduced previously has shown considerable reduction in size, weight, and volume by operating at a higher frequency.
In this dissertation, the concept of the electronic transformer is further extended to the auto-connected phase-shifting type to reduce harmonics generated by nonlinear loads. It is shown that with the addition of primary side and secondary side AC/AC converters achieves phase-shifting. With the addition of converters, magnetic components are operated at a higher frequency to yield a smaller size and weight. Two types of auto-connected electronic transformer configurations are explored. In the first configuration, the secondary converter is eliminated and the output is suitable for rectifier type loads such as adjustable speed drives. In the second configuration, the
secondary converter is added to obtain a sinusoidal phase-shifted AC output voltage. This approach is applicable in general applications. With the proposed approaches, the th and 7th harmonic in utility line currents, generated by two sets of nonlinear loads, are subtracted within the electronic transformer, thereby reducing the total harmonic distortion (THD) of the line current. The analysis and simulation results are presented.
In the second part of the dissertation, the electronic transformer concept is applied to a telecommunication power supply (-48 VDC) system. The proposed approach consists of a matrix converter to convert the low frequency three-phase input AC utility to a high frequency AC output without a DC-link. The output of the matrix converter is then processed via a high frequency isolation transformer to produce -48 VDC. Digital control of the system ensures that the output voltage is regulated and the input currents are of high quality, devoid of low frequency harmonics and at near unity input power factor under varying load conditions. Due to the absence of DC-link electrolytic capacitors, the power density of the proposed rectifier is shown to be higher. Analysis, design example and experimental results are presented from a three-phase 208 V, 1.5 kW laboratory prototype converter.
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Guo, Wennan. "An ac-ac inverter for high frequency power distribution system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ59305.pdf.
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Whitcomb, Clifford Alan. "Composite system analysis of advanced shipboard electrical power distribution systems." Thesis, Cambridge, Massachusetts : Massachusetts Institute of Technology, 1992. http://handle.dtic.mil/100.2/ADA254851.
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Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1992 and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.Thesis Advisor: Kirtley, James L., Jr. "May 1992." Description based on title screen as viewed on March 30, 2009. Includes bibliographical references (p. 73-74). Also available in print.
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Weinstein, Lee. "Scale free networks and their power law distribution." Diss., Connect to the thesis, 2005. http://hdl.handle.net/10066/3880.
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Youssef, Tarek. "Co-design of Security Aware Power System Distribution Architecture as Cyber Physical System." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3210.
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The modern smart grid would involve deep integration between measurement nodes, communication systems, artificial intelligence, power electronics and distributed resources. On one hand, this type of integration can dramatically improve the grid performance and efficiency, but on the other, it can also introduce new types of vulnerabilities to the grid. To obtain the best performance, while minimizing the risk of vulnerabilities, the physical power system must be designed as a security aware system.
In this dissertation, an interoperability and communication framework for microgrid control and Cyber Physical system enhancements is designed and implemented taking into account cyber and physical security aspects. The proposed data-centric interoperability layer provides a common data bus and a resilient control network for seamless integration of distributed energy resources. In addition, a synchronized measurement network and advanced metering infrastructure were developed to provide real-time monitoring for active distribution networks.
A hybrid hardware/software testbed environment was developed to represent the smart grid as a cyber-physical system through hardware and software in the loop simulation methods. In addition it provides a flexible interface for remote integration and experimentation of attack scenarios.
The work in this dissertation utilizes communication technologies to enhance the performance of the DC microgrids and distribution networks by extending the application of the GPS synchronization to the DC Networks. GPS synchronization allows the operation of distributed DC-DC converters as an interleaved converters system. Along with the GPS synchronization, carrier extraction synchronization technique was developed to improve the system’s security and reliability in the case of GPS signal spoofing or jamming.
To improve the integration of the microgrid with the utility system, new synchronization and islanding detection algorithms were developed. The developed algorithms overcome the problem of SCADA and PMU based islanding detection methods such as communication failure and frequency stability. In addition, a real-time energy management system with online optimization was developed to manage the energy resources within the microgrid. The security and privacy were also addressed in both the cyber and physical levels. For the physical design, two techniques were developed to address the physical privacy issues by changing the current and electromagnetic signature. For the cyber level, a security mechanism for IEC 61850 GOOSE messages was developed to address the security shortcomings in the standard.
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Thompson, Jeffrey Craig. "An expert system for protection system design of interconnected electrical distribution circuits." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-170345/.
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Fallier, William F. "Analysis of system wide distortion in an integrated power system utilizing a high voltage DC bus and silicon carbide power devices." Thesis, Monterey, California. Naval Postgraduate School, 2007. http://hdl.handle.net/10945/3006.
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This research investigates the distortion on the electrical distribution system for a high voltage DC Integrated Power System (IPS). The analysis was concentrated on the power supplied to a propulsion motor driven by an inverter with simulated silicon carbide switches. Theoretically, silicon carbide switches have the advantage of being able to withstand a very large blocking voltage and carry very large forward currents. Silicon carbide switches are also very efficient due to their quick rise and fall times. Since silicon carbide switches can withstand high voltage differentials and switch faster than silicon switches, the switching effects on the electrical distribution system were investigated. The current state of silicon carbide power electronics was also investigated. This research quantifies the current and voltage distortion over various operating conditions. A system model was developed using Matlab, Simulink, and SimPowerSystems. The model consisted of a synchronous generator supplying a rectifier and inverter set driving an induction motor. This induction motor simulates the propulsion motor for a Navy ship. This model had a DC link voltage of 10 kV in order to simulate future Navy IPS systems. The current and voltage distortion were compared to MIL STD 1399 and IEEE STD 519 and 45.Contract Number: N62271-97-G-0026
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Weerasinghe, Handuwala Dewage Dulan Jayanatha. "Planning optimal load distribution and maximum renewable energy from wind power on a radial distribution system." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/28714.
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Doctor of PhilosophyElectrical and Computer Engineering
Ruth D. Miller
Optimizing renewable distributed generation in distribution systems has gained popularity with changes in federal energy policies. Various studies have been reported in this regard and most of the studies are based on optimum wind and/or solar generation planning in distribution system using various optimization techniques such as analytical, numerical, and heuristic. However, characteristics such as high energy density, relatively lower footprint of land, availability, and local reactive power compensation ability, have gained increased popularity for optimizing distributed wind generation (DWG) in distribution systems. This research investigated optimum distributed generation planning (ODGP) using two primary optimization techniques: analytical and heuristic. In first part of the research, an analytical optimization method called “Combined Electrical Topology (CET)” was proposed in order to minimize the impact of intentional structural changes in distribution system topology, in distributed generation/ DWG placement. Even though it is still rare, DWG could be maximized to supply base power demand of three-phase unbalanced radial distribution system, combined with distributed battery energy storage systems (BESS). In second part of this research the usage of DWG/BESS as base power generation, and to extend the ability to sustain the system in a power grid failure for a maximum of 1.5 hours was studied. IEEE 37-node, three-phase unbalanced radial distribution system was used as the test system to optimize wind turbines and sodium sulfide (NaS) battery units with respect to network real power losses, system voltage profile, DWG/BESS availability and present value of cost savings. In addition, DWG’s ability to supply local reactive power in distribution system was also investigated. Model results suggested that DWG/NaS could supply base power demand of a threephase unbalanced radial distribution system. In addition, DWG/NaS were able to sustain power demand of a three-phase unbalanced distribution system for 1.5 hours in the event of a power grid failure.
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Thandi, Gurjit Singh. "Modeling, Control and Stability Analysis of a PEBB Based DC Distribution Power System." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36788.
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Power Electronic Building Block (PEBB) concept is to provide generic building blocks for power conversion, regulation and distribution with control intelligence and autonomy. A comprehensive modeling and analysis of a PEBB based DC distributed power system (DPS), comprising of a front end power factor correction (PFC) boost rectifier, a DC-DC converter and a three phase four leg inverter is performed. All the sub-systems of the DC DPS are modeled and analyzed for stability and good transient performance.
A comprehensive stability analysis of a PEBB based DC DPS is performed. The effect of impedance overlap on the system and individual sub-systems is examined. Ability of a PEBB based converter to stabilize the integrated system by actively changing the system bandwidth is presented. The fault tolerance capability in a PEBB based rectifier is established by ensuring stable system operation, with one leg of the rectifier failed open-circuited.
Master of Science
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Hämäläinen, J. (Joona). "Register-transfer-level power profiling for system-on-chip power distribution network design and signoff." Master's thesis, University of Oulu, 2019. http://jultika.oulu.fi/Record/nbnfioulu-201905141744.
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Abstract. This thesis is a study of how register-transfer-level (RTL) power profiling can help the design and signoff of power distribution network in digital integrated circuits. RTL power profiling is a method which collects RTL power estimation results to a single power profile which then can be analysed in order to find interesting time windows for specifying power distribution network design and signoff.
The thesis starts with theory part. Complementary metal-oxide semiconductor (CMOS) inverter power dissipation is studied at first. Next, power distribution network structure and voltage drop problems are introduced. Voltage drop is demonstrated by using power distribution network impedance figures. Common on-chip power distribution network structure is introduced, and power distribution network design flow is outlined. Finally, decoupling capacitors function and impact on power distribution network impedance are thoroughly explained.
The practical part of the thesis contains RTL power profiling flow details and power profiling flow results for one simulation case in one design block. Also, some methods of improving RTL power estimation accuracy are discussed and calibration with extracted parasitic is then used to get new set of power profiling time windows. After the results are presented, overall RTL power estimation accuracy is analysed and resulted time windows are compared to reference gate-level time windows. RTL power profiling result analysis shows that resulted time windows match the theory and RTL power profiling seems to be a promising method for finding time windows for power distribution network design and signoff.Rekisterisiirtotason tehoprofilointi järjestelmäpiirin tehonsiirtoverkon suunnittelussa ja verifioinnissa. Tiivistelmä. Tässä työssä tutkitaan, miten rekisterisiirtotason (RTL) tehoprofilointi voi auttaa digitaalisten integroitujen piirien tehonsiirtoverkon suunnittelussa ja verifioinnissa. RTL-tehoprofilointi on menetelmä, joka analysoi RTL-tehoestimoinnista saadusta tehokäyrästä hyödyllisiä aikaikkunoita tehonsiirtoverkon suunnitteluun ja verifiointiin.
Työ alkaa teoriaosuudella, jonka aluksi selitetään, miten CMOS-invertteri kuluttaa tehoa. Seuravaksi esitellään tehonsiirtoverkon rakenne ja pahimmat tehonsiirtoverkon jännitehäviön aiheuttajat. Jännitehäviötä havainnollistetaan myös piirikaavioiden ja impedanssikäyrien avustuksella. Lisäksi integroidun piirin tehonsiirtoverkon suunnitteluvuo ja yleisin rakenne on esitelty. Lopuksi teoriaosuus käsittelee yksityiskohtaisesti ohituskondensaattoreiden toiminnan ja vaikutuksen tehonsiirtoverkon kokonaisimpedanssiin.
Työn kokeellisessa osuudessa esitellään ensin tehoprofiloinnin vuo ja sen jälkeen vuon tulokset yhdelle esimerkkilohkolle yhdessä simulaatioajossa. Lisäksi tässä osiossa käsitellään RTL-tehoestimoinnin tarkkuutta ja tehdään RTL-tehoprofilointi loisimpedansseilla kalibroidulle RTL-mallille. Lopuksi RTL-tehoestimoinnin tuloksia ja saatuja RTL-tehoprofiloinnin aikaikkunoita analysoidaan ja verrataan porttitason mallin tuloksiin. RTL-tehoprofiloinnin tulosten analysointi osoittaa, että saatavat aikaikkunat vastaavat teoriaa ja että RTL-tehoprofilointi näyttää lupaavalta menetelmältä tehosiirtoverkon analysoinnin ja verifioinnin aikaikkunoiden löytämiseen.
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Kavi, Moses. "Smart protection system for future power system distribution networks with increased distributed energy resources." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/124628/1/Moses_Kavi_Thesis.pdf.
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This thesis investigates the impact of increased penetration of distributed energy resources (DERs) on the power system distribution network protection system which has been designed on the premise of passive radial network with unidirectional power flow. The investigation involved developing a multistage morphological fault detection and diagnostic tool called the decomposed open-close alternating sequence algorithm using a signal processing technique called mathematical morphology. This investigation culminated in proposing new strategies for; adaptive overcurrent protection in AC radial distribution network with increased DER penetration and high impedance arc-fault detection in AC and DC power distribution networks.
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Scott, Nigel Clive. "Limitation of distribution system voltage by decentralised load control." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327325.
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Yu, Qiuli. "Multi-agent systems for reconfiguration of shipboard integrated power system including AC-DC zonal distribution system." Diss., Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-11072008-122943.
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Wang, Zhuding. "Distribution system planning a set of new formulations and hybrid algorithms /." online access from Digital Dissertation Consortium access full-text, 2000. http://libweb.cityu.edu.hk/cgi-bin/er/db/ddcdiss.pl?9994047.
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Mahajan, Nikhil R. "System Protection for Power Electronic Building Block Based DC Distribution Systems." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-12052004-233822/.
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The purpose of this research has been to develop an agent based protection and reconfiguration scheme for power electronic building block based (PEBB) DC distribution systems. One of the foremost applications would be in the new zonal DC distribution on naval ships. The research involves the design of an agent based protection scheme which uses the PEBBs for current limiting and circuit breaking purposes. Considerations are given to reduce the system downtime under fault conditions, allow proper coordination and provide backup protection. The research also involves the design of a reconfiguration management scheme based on collaborative agents. The collaboration ensures that the reconfiguration is achieved at a global level, enhancing the system survivability under the conditions of multiple faults and damages. The coordination ensures that only the faulted part of the system is isolated and the reconfiguration makes sure that the power to the healthy part of the system is supplied continuously. The reconfiguration management also performs load shedding if the generation does not meet the load demand of the reconfigured system due to a fault or damage in the generator.
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Nordqvist, Emil. "Preliminary design of a modular high altitude balloon power distribution system." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79762.
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This thesis conducts research into different rechargeable battery technologies and their applicability to the high altitude balloon flights conducted at Esrange space center. The research focuses on the possible use of lithium ion batteries’, sodium ion batteries, nickel metal hydrate, and Metal hydridelithiumion batteries. Resulting in lithium ion batteries in 18650 cells being recommended. The thesis continues with a modular power distribution system architecture design. The system architecture is established with solarcharging capabilities, up to 1500W peak output power, over 600W continuous output power, multiple output voltages, more than six output channels, remote output power switching, and monitoring of power consumption. A prototype is built from this architecture on which limited testing is performed.The testing shines light on future improvements and displays proof of concept for some parts.
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Moberg, Elias. "The value of flexibility in a future electric power distribution system." Thesis, Uppsala universitet, Industriell teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447539.
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The size and composition of the Swedish electricity generation are changing. This, in combination with new legal requirements from regulatory entities including the EU Directive 2019/944, creates several challenges for the design of the future system. Among other things, the directive suggests that flexibility solutions are to be integrated into grids to increase the degree of utilization and avoid congestions, when socio-economically profitable. This thesis evaluates what this could mean in a Swedish context, in combination with providing a basic understanding of the contradictions that can arise between a desired efficient grid use in an energy system that goes towards more distributed and intermittent energy generation sources. The work is carried out in collaboration with Vattenfall Eldistribution AB, focusing on the geographical area of Uppsala and Stockholm, the Swedish region hit hardest by local congestions. The work assumes that the economic value of a flexibility solution is at most equivalent to the cost of a conventional new construction aimed at capacity strengthening, or the Value of Lost Load (VoLL). The report’s most important deliverable is a model based on this view. The model is used to evaluate the economic value of flexibility per kWh, in three regional grid construction projects within the mentioned region. The results show that there is a great potential for using flexibility resources to increase utilization in grids and also to optimize the costs that society pays for this infrastructure by such methods. However, the work concludes that the usage of flexible technologies primarily is to adapt electric consumption with intermittent energy generation, rather than being used to solve local grid capacity shortages.
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Arunachalam, Suresh. "Expansion of an existing power system - a study." Diss., Rolla, Mo. : University of Missouri--Rolla, 1989. http://scholarsmine.mst.edu/thesis/pdf/Arunachalam_09007dcc805881ce.pdf.
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Thesis (M.S.)--University of Missouri--Rolla, 1989.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed October 7, 2008) Includes bibliographical references (p. 89).
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Singh, Manish K. "Optimal Operation of Water and Power Distribution Networks." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/86860.
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Under the envisioned smart city paradigm, there is an increasing demand for the coordinated operation of our infrastructure networks. In this context, this thesis puts forth a comprehensive toolbox for the optimization of electric power and water distribution networks. On the analytical front, the toolbox consists of novel mixed-integer (non)-linear program (MINLP) formulations; convex relaxations with optimality guarantees; and the powerful technique of McCormick linearization. On the application side, the developed tools support the operation of each of the infrastructure networks independently, but also towards their joint operation. Starting with water distribution networks, the main difficulty in solving any (optimal-) water flow problem stems from a piecewise quadratic pressure drop law. To efficiently handle these constraints, we have first formulated a novel MINLP, and then proposed a relaxation of the pressure drop constraints to yield a mixed-integer second-order cone program. Further, a novel penalty term is appended to the cost that guarantees optimality and exactness under pre-defined network conditions. This contribution can be used to solve the WF problem; the OWF task of minimizing the pumping cost satisfying operational constraints; and the task of scheduling the operation of tanks to maximize the water service time in an area experiencing electric power outage. Regarding electric power systems, a novel MILP formulation for distribution restoration using binary indicator vectors on graph properties alongside exact McCormick linearization is proposed. This can be used to minimize the restoration time of an electric system under critical operational constraints, and to enable a coordinated response with the water utilities during outages.Master of Science
The advent of smart cities has promoted research towards interdependent operation of utilities such as water and power systems. While power system analysis is significantly developed due to decades of focused research, water networks have been relying on relatively less sophisticated tools. In this context, this thesis develops Advanced efficient computational tools for the analysis and optimization for water distribution networks. Given the consumer demands, an optimal water flow (OWF) problem for minimizing the pump operation cost is formulated. Developing a rigorous analytical framework, the proposed formulation provides significant computational improvements without compromising on the accuracy. Explicit network conditions are provided that guarantee the optimality and feasibility of the obtained OWF solution. The developed formulation is next used to solve two practical problems: the water flow problem, that solves the complex physical equations yielding nodal pressures and pipeline flows given the demands/injections; and an OWF problem that finds the best operational strategy for water utilities during power outages. The latter helps the water utility to maximize their service time during power outages, and helps power utilities better plan their restoration strategy. While the increased instrumentation and automation has enabled power utilities to better manage restoration during outages, finding an optimal strategy remains a difficult problem. The operational and coordination requirements for the upcoming distributed resources and microgrids further complicate the problem. This thesis develops a computationally fast and reasonably accurate power distribution restoration scheme enabling optimal coordination of different generators with optimal islanding. Numerical tests are conducted on benchmark water and power networks to corroborate the claims of the developed formulations.
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Khaliq, Abdul. "Preventive control for the attainment of a dynamically secure power system." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/13893.
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Golder, Andrew S. Miu Karen Nan. "Photovoltaic generator modeling for large scale distribution system studies /." Philadelphia, Pa. : Drexel University, 2006. http://hdl.handle.net/1860/1220.
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Bank, Jason Noah. "Propagation of Electromechanical Disturbances across Large Interconnected Power Systems and Extraction of Associated Modal Content from Measurement Data." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/73008.
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Changes in power system operating conditions cause dynamic changes in angle and frequency. These disturbances propagate throughout the system area with finite speed. This propagation takes the form of a traveling wave whose arrival time at a particular point in the system can be observed using a wide-area measurement system (WAMS). Observations of these waves both through simulation and measurement data have demonstrated several factors that influence the speed at which a disturbance propagates through a system. Results of this testing are presented which demonstrate dependence on generator inertia, damping and line impedance. Considering a power system as an area with and uneven distribution of these parameters it is observed that a disturbance will propagate throughout a system at different rates in differing directions. This knowledge has applications in locating the originating point of a system disturbance, understanding the overall dynamic response of a power system, and determining the dependencies between various parts of that system.
A simplified power system simulator is developed using the swing equation and system power flow equations. This simplified modeling technique captures the phenomenon of traveling electromechanical waves and demonstrates the same dependencies as data derived from measurements and commercial power system simulation packages. The ultimate goal of this research is develop a methodology to approximate a real system with this simplified wave propagation model. In this architecture each measurement point would represent a pseudo-bus in the model. This procedure effectively lumps areas of the system into one equivalent bus with appropriately sized generators and loads. With the architecture of this reduced network determined its parameters maybe estimated so as to provide a best fit to the measurement data. Doing this effectively derives a data-driven equivalent system model. With an appropriate equivalent model for a given system determined, incoming measurement data can be processed in real time to provide an indication of the system operating point. Additionally as the system state is read in through measurement data future measurements values along the same trajectory can be estimated. These estimates of future system values can provide information for advanced control and protection schemes.
Finally a procedure for the identification and extraction of inter-area oscillations is developed. The dominant oscillatory frequency is identified from an event region then fit across the surrounding dataset. For each segment of this data set values of amplitude, phase and damping are derived for each measurement vector. Doing this builds up a picture of how the oscillation evolves over time and responds to system conditions. These results are presented in a graphical format as a movie tracking the modal phasors over time. Examples derived from real world measurement data are presented.Ph. D.
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Fang, Yong Jie. "Dynamic and transient system control using fast acting quadrature boosters." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244084.
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Janovsky, Pavel. "Large-scale coalition formation: application in power distribution systems." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35328.
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Doctor of PhilosophyDepartment of Computing and Information Sciences
Scott A. DeLoach
Coalition formation is a key cooperative behavior of a system of multiple autonomous agents. When the capabilities of individual agents are not su fficient for the improvement of well-being of the individual agents or of the entire system, the agents can bene t by joining forces together in coalitions. Coalition formation is a technique for finding coalitions that are best fi tted to achieve individual or group goals. This is a computationally expensive task because often all combinations of agents have to be considered in order to find the best assignments of agents to coalitions. Previous research has therefore focused mainly on small-scale or otherwise restricted systems. In this thesis we study coalition formation in large-scale multi-agent systems. We propose an approach for coalition formation based on multi-agent simulation. This approach allows us to find coalitions in systems with thousands of agents. It also lets us modify behaviors of individual agents in order to better match a specific coalition formation application. Finally, our approach can consider both social welfare of the multi-agent system and well-being of individual self-interested agents. Power distribution systems are used to deliver electric energy from the transmission system to households. Because of the increased availability of distributed generation using renewable resources, push towards higher use of renewable energy, and increasing use of electric vehicles, the power distribution systems are undergoing signi ficant changes towards active consumers who participate in both supply and demand sides of the electricity market and the underlying power grid. In this thesis we address the ongoing change in power distribution systems by studying how the use of renewable energy can be increased with the help of coalition formation. We propose an approach that lets renewable generators, which face uncertainty in generation prediction, to form coalitions with energy stores, which on the other hand are always able to deliver the committed power. These coalitions help decrease the uncertainty of the power generation of renewable generators, consequently allowing the generators to increase their use of renewable energy while at the same time increasing their pro fits. Energy stores also bene t from participating in coalitions with renewable generators, because they receive payments from the generators for the availability of their power at speci fic time slots. We first study this problem assuming no physical constraints of the underlying power grid. Then we analyze how coalition formation of renewable generators and energy stores in a power grid with physical constraints impacts the state of the grid, and we propose agent behavior that leads to increase in use of renewable energy as well as maintains stability of the grid.
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Labricciosa, Ivano N. "A case study of power quality enhancement in an electrical distribution system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0027/MQ51617.pdf.
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Fu, Hao. "Market-oriented micro virtual power prosumers operations in distribution system operator framework." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7516/.
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As the European Union is on track to meet its 2020 energy targets on raising the share of renewable energy and increasing the efficiency in the energy consumption, considerable attention has been given to the integration of distributed energy resources (DERs) into the restructured distribution system. This thesis proposes market-oriented operations of micro virtual power prosumers (J.lVPPs) in the distribution system operator framework, in which the J.lVPPs evolve from home-oriented energy management systems to price-taking prosumers and to price-making prosumers. Considering the diversity of the DERs installed in the residential sector, a configurable J.l VPP is proposed first to deliver multiple energy services using a fuzzy logic-based generic algorithm. By responding to the retail price dynamics and applying load control, the J.lVPP achieves considerable electricity bill savings, active utilisation of energy storage system and fast return on investment. As the J.lVPPs enter the distribution system market, they are modelled as price-takers in a two-settlement market first and a chance-constrained formulation is proposed to derive the bidding strategies. The obtained strategy demonstrates its ability to bring the J.l VPP maximum profit based on different composition of DERs and to maintain adequate supply capacity to meet the demand considering the volatile renewable generation and load forecast. Given the non-cooperative nature of the actual market, the J.l VPPs are transformed into price-makers and their market behaviours are studied in the context of electricity market equilibrium models. The resulted equilibrium problems with equilibrium constraints (EPEC) are presented and solved using a novel application of coevolutionary approach. Compared with the roles of home-oriented energy management systems and price-taking prosumers, the J.lVPPs as price making prosumers have an improved utilisation rate of the installed DER capacity and a guaranteed profit from participating in the distribution system market.
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Pinto, Sampaio Gomes Douglas. "Vegetation High-Impedance Fault Detection and Characterization using Machine Learning." Thesis, 2020. https://vuir.vu.edu.au/41839/.
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Vegetation High-Impedance Faults (VHIFs) are relevant and under-addressed power dis- tribution system disturbances. They are low-energy events, represented by the contact between power lines and nearby vegetation, that are not detected by traditional protection devices. Despite not harmful to power equipment, they can ignite fires in vegetation with great potential to life and property damage. After devastating HIF-related fires in 2009, the Victorian Government found the lack of technical solutions to prevent similar disasters and funded a vegetation ignition testing program to foster further research. It staged hundreds of VHIFs that generated the data pertained to this thesis.
In the related literature, High-Impedance Faults (HIFs) comprise an extensive research field, but few works are solely dedicated to studying VHIFs. Although generally treated as a single problem, different high-impedance conducting surfaces introduce significant variance in faults’ characteristics and behaviours. For these reasons, the staged VHIFs recordings represent a niche type of faults having specific behaviours with significant potential for insights regarding phenomenon characterization.
The main contributions from this thesis result from using the staged VHIF data to address the knowledge gaps related to its characterization and detection method. Initial investigations presented the likely presence of discriminative features in the signals’ high- frequency (HF) spectrum. The results gave confidence for the production of a machine learning-based VHIF classifier, conceptualized and discussed as part of a potential detection method. Subsequently, the existence of discriminative information and invariance in the HF signals was proved with the application of renowned signal representation techniques and machine learning algorithms. A study regarding the importance of using HF signals was also performed to support the chosen approach when conceptualizing the classifier. It led to the finding that although the accessibility of such signals might be not optimal, they may be imperative for an effective VHIF detection method. To deflate some of the potential implementation concerns, a low-cost, proof-of-concept prototype was produced, attesting the capabilities of real-time classification. Lastly, an unsupervised learning technique was used to capture some of the convoluted and complex fault signatures in the time domain. The found patterns led to insights about VHIF behaviour and signatures signals that resulted in more detailed phenomena characterization.
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Paracha, Zahir Javed. "Design and development of intelligent computational techniques for power quality data monitoring and management." Thesis, 2011. https://vuir.vu.edu.au/19381/.
Full textAbstract:
The most important requirement of power system operations is sustained availability and quality supply of electric power. In Electrical Power Distribution System (EPDS), non-linear loads are the main cause of power quality (PQ) degradation. The PQ problems generated by these non-linear loads are complex and diversified in nature. The power system which is not capable to handle non-linear loads faces the problem of voltage unbalance, sag, swell, momentary or temporary interruption and ultimately complete outage of EPDS. The PQ problems have motivated power system engineers to design and develop new methodologies and techniques to enhance EPDS performance. To do so, they are required to analyse the PQ data of the system under consideration. Since, the density of the monitoring nodes in EPDS is quite high, the aggregate analysis is computationally involved. In addition, the cost involved with the PQ shortcomings is significantly high (for domestic consumers and rises exponentially for industrial consumers), hence it also becomes mandatory to project /predict the undesired PQ disturbance in EPDS. This will provides power system engineers to formulate intelligent strategy for efficient power system operations. This objective of the research is to identify and exploit the hidden correlation in PQ data with minimal computational cost and further use this knowledge to classify any PQ disturbance that may occur. ... Further this research also investigates the power distribution system behaviour considering the relationship of main PQ disturbance harmonics in conjunction with the other major PQ parameters i.e. voltage unbalance, sag, swell and frequency.