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Hasanović, Amer. "A simulation and analysis toolbox for power systems and genetic algorithm based damping controller design." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2173.
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Thesis (M.S.)--West Virginia University, 2001.<br>Title from document title page. Document formatted into pages; contains viii, 73 p. : ill. Includes abstract. Includes bibliographical references (p. 71-73).
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Waernlund, Angelica. "Modelling the Nordic Hydro Power System with Spine Toolbox." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-293977.
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In the Nordic power system, the largest balancing resource is hydro power. For future developments of the Nordic power system with more renewable and varying energy, such as wind power, the hydro power and its limitations must thus be taken into account. To be able to study this, a model with these limitations is needed. In earlier projects at KTH, a model of the Swedish hydro power system was built, but with the interconnected Nordic power system and the large amount of hydro power in Norway, the Norwegian hydro power system also needs to be considered. In this project, a model of both the Swedish and Norwegian hydro power system is built. Most of the data of the Swedish hydro power system is reused from the earlier projects, while new data of the Norwegian hydro power system is collected. Also data of transmission capacities and power generation and consumption for all areas, both in Sweden and Norway, were needed. Most of the data could be found, or calculated from, the Norwegian Water Resources and Energy Directorate, Nord Pool and Svenska Kraftnät. The new model built in this project includes 363 Norwegian and 256 Swedish hydro power plants, divided into four Swedish and five Norwegian electricity areas. The model is built in Spine Toolbox and is an expanded and remade model based on an earlier, smaller model of the Skellefte river, which maximised the profits of sold electricity. In this project the model is changed to instead minimise the spillage and explore the flexibility of the hydro power system. That is, its possibility to adjust its power generation to both variable levels of demand and other sources of power generation without being forced to spill water. The results from the simulations were hourly values of water flow between hydro power plants, discharged water and spilled water, electricity flow from each hydro power plant and between electricity areas, and reservoir volumes in each reservoir. From this, the simulated production in Sweden, Norway and all their electricity areas could be compared to real data of energy production. This comparison showed that the total simulated production was very similar to real data when factoring out import and export. The spillage and reservoir volumes were also discussed. Further work could improve the models performance, for example adding import and export, implementing minimum reservoir volumes, and base local inflow of water on real data, but overall the model provided promising results. This project has shown that is it possible to build large models in Spine, and adjust them to investigate different cases.<br>I det nordiska kraftsystemet är vattenkraft den största resursen för att balansera variationer i elproduktion. För framtida ändringar och utbyggnader i kraftsystemet med mer förnybara och varierade energikällor, som vindkraft, måste vattenkraften och dess begränsningar tas hänsyn till. För att kunna studera det nordiska kraftsystemet behövs en modell som tar häsyn till dessa begränsningar. I tidigare projekt på KTH togs en modell av det svenska vattenkraftsystemet fram, men med det sammankopplade nordiska kraftsystemet och den stora mängden vattenkraft i Norge, måste även Norges vattenkraftsystem beaktas. I detta projekt skapas en modell över det svenska och norska vattenkraftsystemet. Majoriteten av data för det svenska vattenkraftsystemet återanvänds från tidigare projekt, medan ny data för det norska vattenkraftsystemet samlas in. Även data över överföringskapaciteter och elproduktion och konsumtion för alla områden, både i Sverige och Norge, behövdes. Den nya modellen som byggs i detta projekt inkluderar 363 norska och 256 svenska vattenkraftverk, uppdelade i fyra elområden i Sverige, och fem i Norge. Modellen byggs i Spine Toolbox, och är en ombyggd och expanderad modell, baserad på en tidigare, mindre modell av Skellefteälven som maximerade inkomst från såld energi. I detta projekt ändras modellen till att istället minimera spillet och undersöka flexibiliteten i vattenkraftsystemet. Det vill säga, dess möjlighet att anpassa kraftproduktionen till både varierande efterfrågan och annan elproduktion, utan att tvingas spilla vatten. Resultaten från simuleringarna bestod av timvärden för vattenflöde mellan vattenkraftverk, tappat och spillt vatten, flöde av el från varje kraftverk och mellan elområden, och magasinvolymer. Den simulerade elproduktionen i Sverige, Norge och i alla elområden kunde sedan jämföras med verklig data. Denna jämförelse visade att den totala simulerade produktionen var mycket lik den verkliga vattenkraftproduktionen med import och export exkluderat. Även spill och magasinvolymer diskuterades. Ytterligare arbete kan ge en ännu bättre modell, exempelvis kan framtida arbete vara att lägga till export och import, implementera minimala magasinvolymer, och lägga in verklig data för lokalt inflöde av vatten, men överlag gav dock modellen lovande resultat. Detta projekt har visat att det är möjligt att skapa stora modeller över energisystem i Spine, och anpassa dem för att undersöka olika scenarion och se hur framtida förändringar i kraftsystemet kan påverka, och påverkas av, vattenkraftsystemet.
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Silva, Luisa Santiago Contreiras Brito da. "Quantitative analysis of the autonomic nervous system : toolbox development and application." reponame:Repositório Institucional da UnB, 2017. http://repositorio.unb.br/handle/10482/31424.
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Previous issue date: 2018-03-13<br>Fundação de Apoio à Pesquisa do Distrito Federal (FAP-DF).<br>A dinâmica entre a PA e a FC é de malha fechada, na qual a PA influencia a FC através do baroreflexo e a FC influencia a PA através da dinâmica circulatória. A respiração exerce uma influência direta sobre a FC que é mediada pelo SNA, chamada de acoplamento cardiorrespiratório (ACR), e também um efeito mecânico indireto mediado pelo baroreflexo. Enquanto análises espectrais univariáveis e bivariáveis podem ser usadas para avaliar esses mecanismos, são técnicas de malha aberta que são incapazes de diferenciar efeitos de retroalimentação dos efeitos de alimentação direta e também de separar o ACR das influências indiretas da respiração na FC. Para lidar com essas limitações, uma abordagem de identificação de sistemas foi aplicada. O CRSIDLab implementa três modelos: o modelo AR com entradas exógenas (ARX), o modelo de funções de base de Laguerre (FBL) e o modelo de funções de base de Meixner (FBM). As respostas ao impulso, que caracterizam a dinâmica entre cada par de variáveis, são calculadas a partir do modelo estimado. Esses modelos são capazes de isolar o ACR ao considerar ambos VPI e PAS como entradas e conseguem abrir a malha do baroreflexo computacionalmente pela imposição de atrasos entre a PAS e o IRR, caracterizando a resposta ao impulso do baroreflexo arterial (BRA). A partir dessas análises, não só o ganho em cada banda de frequência é fornecido através da transformada de Fourier da resposta ao impulso, mas também informações temporais como o atraso entre duas variáveis. Os resultados mostram que ficar de pé é acompanhado por uma supressão vagal e tom vascular simpático aumentado. Análises de correlação mostraram que as estimativas de ASR e SBR baseadas em análises espectrais não apresentam a mesma informação que as estimativas baseadas no modelo de ACR e BRA. As diferenças encontradas sugerem que as análises baseadas em modelo são efetivas em representar o ACR como uma medida dos efeitos diretos da respiração na FC e o BRA como expressão do baroreflexo independente da dinâmica circulatória. Assim, o CRSIDLab é uma ferramenta poderosa para a determinação não-invasiva de diferentes indicadores quantitativos do SNA. Os resultados mostram que os indicadores estimados refletem a fisiologia subjacente, pois ficar de pé é um estímulo simpático que deveria levar a supressão vagal, conforme observado. Os resultados obtidos também mostram que a abordagem de modelagem de sistemas multivariáveis pode fornecer importantes informações adicionais àquelas encontradas pelas abordagens espectrais mais tradicionais, podendo levar a indicadores quantitativos mais específicos do SNA.<br>The autonomic nervous system (ANS) controls the involuntary functions of the body and its imbalance has been linked to increased risk of cardiac mortality. Heart rate variability (HRV) analysis is usually employed as a non-invasive method for assessing ANS modulation. Traditional measures of HRV are based on the analysis of the beat-to-beat oscillations in heart rate (or its reciprocal, the interval between consecutive R waves on the electrocardiogram - RRI), since heart rate (HR) rhythm is a consequence of sympathetic and parasympathetic activity on the sinoatrial node of the heart. However, these oscillations in beat-to-beat HR are also influenced by mechanisms, such as baroreflex and respiratory sinus arrhythmia (RSA), that affect HRV. Therefore, in this work, a multivariate analysis of the cardiorespiratory system is used. This study consists of two parts: the development of the cardiorespiratory system identification lab (CRSIDLab), a Matlab graphical user interface that provides quantitative indicators of ANS activity from a multivariate system model analysis of cardiorespiratory data, followed by its application on data obtained from subjects in supine and standing postures, illustrating its capabilities. Electrocardiogram (ECG), continuous blood pressure (BP) and airflow were recorded from 23 subjects in supine and standing postures for 10 min and preprocessed on CRSIDLab. In this work the classical HRV and BP variability (BPV) analyses were performed though power spectral density (PSD) analysis of the RRI and the systolic BP (SBP), respectively. CRSIDLab implements three methods for spectral analysis: the Fourier transform, Welch method and AR model. All methods were used to calculate the power of the low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.4 Hz) bands, as the areas under the PSD curve. For the HRV, the LF/HF ratio was also calculated. Traditional baroreflex sensitivity (BRS) estimates were calculated from the relation between HRV and BPV in the LF and HF regions. Spectral transfer functions were estimated between SBP and RRI, characterizing baroreflex, and between instantaneous lung volume (ILV, derived from the airflow record) and RRI, characterizing RSA, or the effects of respiration on HR, for the determination of the LF and HF gains. BRS was estimated from the gains of the transfer function between SBP and RRI.The dynamics between BP and HR are closed-loop, where BP influences HR through baroreflex and HR influences BP through circulatory dynamics. Respiration has a direct influence on HR that is mediated through the ANS, called the respiratory-cardiac coupling (RCC), and also a mechanical indirect effect mediated through baroreflex. While univariate and bivariate spectral analyses can be used to assess these effects, they are open-loop techniques that are unable to differentiate feedforward from feedback effects and also to separate RCC from the indirect effects of respiration on HR. To address these limitations a system model identification approach was applied. CRSIDLab implements three types of models: the autoregressive with exogenous inputs (ARX) model, the Laguerre basis function (LBF) model, and the Meixner basis function (MBF) model. The impulse responses, which characterize the dynamics between each pair of variables, are calculated from the estimated model. These multivariate models are able to isolate RCC by considering both SBP and ILV as system inputs and are able to computationally open the baroreflex loop through the imposition of time delays between SBP and RRI, characterizing the arterial baroreflex (ABR) impulse response. From this analysis not only the gain for each frequency band is provided from the Fourier transform of the impulse response, but also temporal information such as delays between variables. The results show that standing is accompanied by significant vagal withdrawal and increased sympathetic vascular tone. Correlation analyses showed that the spectral-based RSA and BRS estimates do not present the same information as the model-based RCC and ABR estimates. The differences found suggest the model-based analyses are effective in representing RCC as a measure of the direct effects of respiration on HR and ABR as an expression of baroreflex that is independent from circulatory dynamics. Thus, CRSIDLab is a powerful tool for the non-invasive determination of different quantitative indicators of the ANS. The results show that all estimated indicators reflect the underlying physiology, in the sense that standing is a sympathetic stimulus that should lead to vagal withdrawal, as observed. The results obtained also show that the multivariate system modeling approach can provide important additional information to those found by the more traditional spectral analyses approaches, which could potentially lead to more specific quantitative indicators of the ANS.
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Reim, Erich. "Analysis and visualization of historical traffic data collected on the Stockholm highway system." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-102747.
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The congestion due to traffic is a worldwide occurrence in major cities, where also the biggest part of the human population lives. To be able to control and oversee the ongoing traffic development in cities, traffic operators use different methods to observe the current trend. This is done by collecting data from stationary sensors to mobile sensors like floating car data. The data collected from stationary sensors is stored in a central database. This historical traffic data is used for analysis of traffic behavior along the main roadway network in Stockholm. Areas which are highly congested can be located as well as areas where traffic flows without problems. This thesis deals with methods to analyze and visualize the traffic behavior based on historical traffic data, measured in the city of Stockholm. Therefore a toolbox is implemented which is used to figure out bottlenecks and typical speed and flow patterns along the Stockholm highway system. Based on the typical speed and flow patterns, it is possible to calculate areas that are affected of congestion and also to determine whether congestion appears due to an incident or a bottleneck.
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Seyed, Zadeh Sabounchi Nasim. "Extending the System Dynamics Toolbox to Address Policy Problems in Transportation and Health." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/77330.
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System dynamics can be a very useful tool to expand the boundaries of one's mental models to better understand the underlying behavior of systems. But despite its utility, there remains challenges associated with system dynamics modeling that the current research addresses by expanding the system dynamics modeling toolbox. The first challenge relates to imprecision or vagueness, for example, with respect to human perception and linguistic variables. The most common approach is to use table or graph functions to capture the inherent vagueness in these linguistic (qualitative) variables. Yet, combining two or more table functions may lead to further complexity and, moreover, increased difficulty when analyzing the resulting behavior. As part of this research, we extend the system dynamics toolbox by applying fuzzy logic. Then, we select a problem of congestion pricing in mitigating traffic congestion to verify the effectiveness of our integration of fuzzy logic into system dynamics modeling.
Another challenge, in system dynamics modeling, is defining proper equations to predict variables based on numerous studies. In particular, we focus on published equations in models for energy balance and weight change of individuals. For these models there is a need to define a single robust prediction equation for Basal Metabolic Rate (BMR), which is an element of the energy expenditure of the body. In our approach, we perform an extensive literature review to explore the relationship between BMR and different factors including age, body composition, gender, and ethnicity. We find that there are many equations used to estimate BMR, especially for different demographic groups. Further, we find that these equations use different independent variables and, in a few cases, generate inconsistent conclusions. It follows then that selecting a single equation for BMI can be quite difficult for purposes of modeling in a systems dynamics context. Our approach involves conducting a meta-regression to summarize the available prediction equations and identifying the most appropriate model for predicting BMR for different sub-populations. The results of this research potentially could lead to more precise predictions of body weight and enhanced policy interventions to help mitigate serious health issues such as obesity.<br>Ph. D.
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Aboreshaid, Saleh Abdulrahman Saleh. "Composite power system well-being analysis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq24064.pdf.
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Zhang, Zhonghua. "Algorithms for power system security analysis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0025/MQ51827.pdf.
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Estes, Steven Douglas. "Power system analysis suite for Windows." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-02132009-170931/.
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Lv, Chen. "Damping torque analysis of power system stabiliser in power systems." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707821.
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Nowadays the small-signal angular stability problem caused by insufficient damping of low- frequency oscillations threatens the security and integrity of power grids when the power system is developing towards large or even super large interconnected grids. The low-frequency oscillation often persists for a long period of time, and in some cases it may interrupt stable operation of the power system. One effective way of suppressing the oscillations is that the auxiliary controllers called power system stabilisers (PSS) are installed in the excitation system of generators, to provide additional damping to the low-frequency power oscillations. The work presented in this thesis focuses on applying the damping torque analysis to power systems. The main contributions of the work are the following two aspects. Firstly, by using the damping torque analysis, an in-depth study on the damping contribution and distribution in modern power system is carried out. This study provides valuable detailed information about how and why the damping is distributed in the system as well as identifying the most responsible components to the damping. The results of extended analysis can be used to guide planning, operation and control of power systems, and have great value in practice. Secondly, the work has demonstrated that damping torque analysis is not only useful in studying global model of power systems as it was before, but can also be applied in local model of power systems and the new energy power generation systems (such as the wind power generation system). Hence the work significantly enhances the potential of the damping torque analysis technique in practical applications thereby making it comparable to the conventional method of modal analysis.
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Palethorpe, Ben. "A novel system impedance measurement for power system analysis and improvement in power quality." Thesis, University of Nottingham, 2002. http://eprints.nottingham.ac.uk/13199/.
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This thesis presents an investigation of on-line supply impedance measurement. Network impedance values are invaluable for power system modelling and simulation. Without knowledge of a network structure and the impedances that make up that structure it is impossible to simulate or predict harmonic propagation within a plant. If the impedance structure for a plant is known then it may be possible to alleviate voltage distortion problems by simply redistributing sensitive loads to points of low harmonic distortion. Alternatively distorting loads may be repositioned thus removing the need for additional filters or compensation equipment. The supply impedance, in particular, is of interest. At a simple level it is important for wiring, fuse and circuit breaker calculations. It is also important when designing filters for power factor correction or harmonic attenuation. Two novel on-line impedance measurement techniques are presented. Both techniques apply a small disturbance to a power network, using measurements of the subsequent transients it is possible to identify the system impedance at the point of measurement. These techniques are implemented both in simulation and experimentally. Excellent identification was possible for linear impedance networks. The performance of the techniques was also investigated in the presence of various non-linear loads. Limitations to both approaches are identified. An active shunt filter was designed and constructed for this work. Experimental impedance measurement was undertaken using this hardware. It was therefore possible to demonstrate the possibility of impedance measurement using an existing active shunt filter and during its normal operation. Finally experimental measurement data was used to demonstrate the operation of the active shunt filter using reference currents determined from supply voltage and supply impedance.
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Hammer, Anders. "Analysis of IEEE Power System Stabilizer Models." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14035.
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Student:Anders HammerSupervisor:Kjetil UhlenContact:Daniel MotaCollaboration with:Voith HydroProblem descriptionIEEE (Institute of Electrical and Electronics Engineers) presented in 2005 a new PSS structure named IEEE PSS4B (Figure 0 1). Voith Hydro wants to analyse the pros and cons of using this new type compared to older structures. The PSS4B is a multi-band stabilizer that has three separate bands and is specially designed to handle different oscillation frequencies in a wide range. Until now, Voith Hydro has used the common PSS2B in their installations, but in the future they will probably start to implement the new PSS4B. This master thesis will seek to find an answer on following questions:•How should the PSS4B be tuned to give the best damping of the local and inter-area oscillation mode?•Will an implementation of PSS4B give a better result compared to PSS2B?•What are the pros and cons of PSS2B and PSS4B? Figure 0 1: The multi-band stabilizer, IEEE PSS4B [1].MethodIn order to test and compare different PSS models, a simple two-area network model is created in a computer simulation programme (SIMPOW). One of the generating units is a hydro generator, which has a model of a static excitation system made by Voith Hydro. This network is characterised by a poorly damped inter-area oscillation mode, and in addition some local oscillation modes related to each machine. Different PSS structures (PSS2B and PSS4B) are then tuned and installed in the excitation system of the hydro generator, in order to improve the stability of the network. Different tuning methods of the PSS4B are designed, tested and later compared with the more common stabilizer the PSS2B. Simplifications are made where parts of the stabilizer is disconnected in order to adapt the control structure to the applied network and its oscillations. Totally 5 different tuning methods are presented, and all these methods are based on a pole placement approach and tuning of lead/lag-filters. ResultsInitial eigenvalues of the different setups are analysed and several disturbances are studied in time domain analysis, in order to describe the robustness of the system. Figure 2 illustrates the rotor speed of the generator, where the different PSS’s are implemented. PSS4B is clearly resulting in increased damping of all speed oscillations in this network. The same results can also be seen in an eigenvalue analysis.Conclusion The best overall damping obtained in this master thesis occurs when the high frequency band of the PSS4B is tuned first, and in order to maximize the damping of the local oscillation mode in the network. The intermediate frequency band is then tuned as a second step, according to the inter-area oscillation mode. Results of this tuning technique show a better performance of the overall damping in the network, compared to PSS2B. The improvement of the damping of the inter-area oscillation mode is not outstanding, and the reason is that the applied machine is relative small compared to the other generating units in the network. The oscillation modes in the network (local and inter-area) have a relative small frequency deviation. A network containing a wider range of oscillation frequencies will probably obtain a greater advantage of implementing a multi-band stabilizer.
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Baba, Zein El Abidin. "Interactive transient analysis of power system networks." Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315390.
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Dandachi, Najib H. "Network flow method for power system analysis." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47398.
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Zhu, Dan. "Power System Reliability Analysis with Distributed Generators." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/32848.
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Reliability is a key aspect of power system design and planning. In this research we present a reliability analysis algorithm for large scale, radially operated (with respect to substation), reconfigurable, electrical distribution systems. The algorithm takes into account equipment power handling constraints and converges in a matter of seconds on systems containing thousands of components. Linked lists of segments are employed in obtaining the rapid convergence. A power flow calculation is used to check the power handling constraints. The application of distributed generators for electrical distribution systems is a new technology. The placement of distributed generation and its effects on reliability is investigated. Previous reliability calculations have been performed for static load models and inherently make the assumption that system reliability is independent of load. The study presented here evaluates improvement in reliability over a time varying load curve. Reliability indices for load points and the overall system have been developed. A new reliability index is proposed. The new index makes it easier to locate areas where reliability needs to be improved. The usefulness of this new index is demonstrated with numerical examples.<br>Master of Science
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Fernando, Kurukulasuriya Joseph Tilak Nihal. "Soft computing techniques in power system analysis." Thesis, full-text, 2008. https://vuir.vu.edu.au/2025/.
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Soft computing is a concept that has come into prominence in recent times and its application to power system analysis is still more recent. This thesis explores the application of soft computing techniques in the area of voltage stability of power systems.
Soft computing, as opposed to conventional “hard” computing, is a technique that is tolerant of imprecision, uncertainty, partial truth and approximation.
Its methods are based on the working of the human brain and it is commonly known as artificial intelligence. The human brain is capable of arriving at valid conclusions based on incomplete and partial data obtained from prior
experience. It is an approximation of this process on a very small scale that is used in soft computing. Some of the important branches of soft computing (SC) are artificial neural networks (ANNs), fuzzy logic (FL), genetic
computing (GC) and probabilistic reasoning (PR). The soft computing methods are robust and low cost.
It is to be noted that soft computing methods are used in such diverse fields as missile guidance, robotics, industrial plants, pattern recognition, market prediction, patient diagnosis, logistics and of course power system analysis and prediction. However in all these fields its application is comparatively new and research is being carried out continuously in many universities and
research institutions worldwide.
The research presented in this thesis uses the soft computing method of Artificial Neural Networks (ANN’s) for the prediction of voltage instability in power systems. The research is very timely and current and would be a substantial contribution to the present body of knowledge in soft computing and voltage stability, which by itself is a new field. The methods developed in this research would be faster and more economical than presently available methods enabling their use online.
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Fernando, Kurukulasuriya Joseph Tilak Nihal. "Soft computing techniques in power system analysis." full-text, 2008. http://eprints.vu.edu.au/2025/1/thesis.pdf.
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Soft computing is a concept that has come into prominence in recent times and its application to power system analysis is still more recent. This thesis explores the application of soft computing techniques in the area of voltage stability of power systems. Soft computing, as opposed to conventional “hard” computing, is a technique that is tolerant of imprecision, uncertainty, partial truth and approximation. Its methods are based on the working of the human brain and it is commonly known as artificial intelligence. The human brain is capable of arriving at valid conclusions based on incomplete and partial data obtained from prior experience. It is an approximation of this process on a very small scale that is used in soft computing. Some of the important branches of soft computing (SC) are artificial neural networks (ANNs), fuzzy logic (FL), genetic computing (GC) and probabilistic reasoning (PR). The soft computing methods are robust and low cost. It is to be noted that soft computing methods are used in such diverse fields as missile guidance, robotics, industrial plants, pattern recognition, market prediction, patient diagnosis, logistics and of course power system analysis and prediction. However in all these fields its application is comparatively new and research is being carried out continuously in many universities and research institutions worldwide. The research presented in this thesis uses the soft computing method of Artificial Neural Networks (ANN’s) for the prediction of voltage instability in power systems. The research is very timely and current and would be a substantial contribution to the present body of knowledge in soft computing and voltage stability, which by itself is a new field. The methods developed in this research would be faster and more economical than presently available methods enabling their use online.
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Hua, Ke Qian. "Probabilistic power system contingency analysis considering wind." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/79903/1/Ke%20Qian_Hua_Thesis.pdf.
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This thesis was a step forward in developing probabilistic assessment of power system response to faults subject to intermittent generation by renewable energy. It has investigated the wind power fluctuation effect on power system stability, and the developed fast estimation process has demonstrated the feasibility for real-time implementation. A better balance between power network security and efficiency can be achieved based on this research outcome.
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Jirutitijaroen, Panida. "Some optimization problems in power system reliability analysis." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1491.
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Raoofsheibani, Davood [Verfasser]. "Online Power System Security Analysis and State Prediction : Enhanced Power System Models and Tools / Davood Raoofsheibani." Düren : Shaker, 2021. http://d-nb.info/1240853947/34.
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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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Min, Liang. "Decomposition algorithms for multi-area power system analysis." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5919.
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A power system with multiple interconnected areas needs to be operated coordinately
for the purposes of the system reliability and economic operation, although
each area has its own ISO under the market environment. In consolidation of different
areas under a common grid coordinator, analysis of a power system becomes more
computationally demanding. Furthermore, the analysis becomes more challenging
because each area cannot obtain the network operating or economic data of other
areas.
This dissertation investigates decomposition algorithms for multi-area power system
transfer capability analysis and economic dispatch analysis. All of the proposed
algorithms assume that areas do not share their network operating and economic
information among themselves, while they are willing to cooperate via a central coordinator
for system wide analyses.
The first proposed algorithm is based on power transfer distribution factors
(PTDFs). A quadratic approximation, developed for the nonlinear PTDFs, is used to
update tie-line power flows calculated by Repeated Power Flow (RPF). These tie-line
power flows are then treated as injections in the TTC calculation of each area, as
the central entity coordinates these results to determine the final system-wide TTC
value.
The second proposed algorithm is based on REI-type network equivalents. It uses
the Continuation Power Flow (CPF) as the computational tool and, thus, the problem of voltage stability is considered in TTC studies. Each area uses REI equivalents of
external areas to compute its TTC via the CPF. The choice and updating procedure
for the continuation parameter employed by the CPF is implemented in a distributed
but coordinated manner.
The third proposed algorithm is based on inexact penalty functions. The traditional
OPF is treated as the optimization problems with global variables. Quadratic
penalty functions are used to relax the compatible constraints between the global
variables and the local variables. The solution is proposed to be implemented by
using a two-level computational architecture.
All of the proposed algorithms are verified by numerical comparisons between the
integrated and proposed decomposition algorithms. The proposed algorithms lead to
potential gains in the computational efficiency with limited data exchanges among
areas.
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McIlhagger, David. "Acceleration of power system small signal stability analysis." Thesis, Queen's University Belfast, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486529.
Full textAbstract:
Electric power networks comprise large complex interconnections of generation and loads. The generators, and their controllers, are non-linear dynamic systems which on interconnection form a very complex control problem. Traditionally the models used to capture the small signal Rtability of these systems were not highly detailed. This waR jURtified Rince the generation was provided by large centralized power Rtations, however with the current trend towards small scale and diRtributed generation, as provided by.wind farmR and diesel genRetR, the power system modelR require a greater level of detail. This means that the stability assessment of theRe models involves greater detail and requires greater computation time, thus rendering near future predictions obsolete. ThiR thesis studies the methods that are Ilsed to determine • power system small signal stability, in order to provide acceleration to this analysis. A method based on wavelet approximations to provide an approximate solution was developed and its effectiveneRs against the traditional QR algorithm waR investigated. The method was applied to a four generator RyRtem and the IEEE New England 39 bus Rystem. Alternative methods to form accelerating polynomials for eigenvalue methodR were developed and evaluated against the IEEE New England 39 bus system. A new algorithm, called the polygon polynomial Arnoldi method (PPAM) was developed and tested against the implicitly restarted Arnoldi method (IRAM), from the linear algebra literature. The effectiveness of both theRe methods was tested against the IEEE New England 39 bus system and the one area IEEE reliability test system along with that for the QR algorithm.
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Cresswell, Charles. "Steady state load models for power system analysis." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/3846.
Full textAbstract:
The last full review of load models used for power system studies occurred in the 1980s. Since then, new types of loads have been introduced and system load mix has changed considerably. The examples of newly introduced loads include drive-controlled motors, low energy consumption light sources and other modern power electronic loads. Their numbers have been steadily increasing in recent years, a trend which is expected to escalate. Accordingly, the majority of load models used in traditional power system studies are becoming outdated, as they are unable to accurately represent power demand characteristics of existing and future loads. Therefore, in order to accurately predict both active and non-active power demand characteristics of aggregated modern power system loads in different load sectors (e.g. residential, commercial or industrial), existing load models should be updated and new models developed. This thesis aims to fill this gap by developing individual, generic and aggregated steady state models of the most common loads in use today, as well as of those expected to show significant growth in the future. The component-based approach is adopted for load modelling, where individual load models are obtained in detailed simulations of physical devices. Whenever possible, the developed individual load models are validated by measurements. These detailed individual load models are then simplified and expressed as equivalent circuit and analytical models, which allowed the establishment of generic load models that can be easily aggregated. It should be noted that since all non-active power characteristics are correctly represented, the developed aggregated load models allow for a full harmonic analysis, which is not the case with the standard steady state load models. Therefore, the proposed load models form an extensive library of comprehensive load models that are suitable for use in multiple areas of power system research. Based on the results of research related to typical domestic/residential sector load mix, the newly developed load models are aggregated and then applied to a typical UK/Scotland distribution network. Considerable differences are seen between network characteristics of newly proposed and previously developed models. The voltage distortion of a typical distribution system bus is investigated, and it is shown that distortion of the system voltage is likely to increase significantly in the future. The results of the presented research also suggest that neglecting the harmonic characteristics from the set of general load attributes may introduce errors in standard load flow studies.
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Wu, Zhongyu. "Wide Area Analysis and Application in Power System." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/36427.
Full textAbstract:
Frequency monitoring network (FNET) is an Internet based GPS synchronized wide-area frequency monitoring network deployed at distribution level. At first part of this thesis, FNET structure and characteristics are introduced. After analysis and smoothing FDR signals, the algorithm of event trigger is present with Visual C++ DLL programming.
Estimation of disturbance location method is discussed based on the time delay of arriving (TDOA) in the second part of this work. In this section, author shows the multiply method to calculate event time, which is important when deal with pre-disturbance frequency in TDOA part. Two event kinds are classified by the change of frequency and the linear relationship between change of frequency and imbalance of generation and load power is presented. Prove that Time Delay of Arrival (TDOA) is a good algorithm for estimation event location proved by real cases. At last, the interface of DLL module and the key word to import and export DLL variables and function is described. <p>
At last, PSS compensation optimization with a set of nonlinear differential algebraic equations (DAE) is introduced in detail. With combining the bifurcation theory of nonlinear system and the optimization theory, the optimal control of small-signal stability of power electric systems are solved. From the perspective of stability margin, global coordination of controller parameters is studied to ensure the stable operation of power grids. The main contents of this thesis include:<p>
ï¼ 1ï¼ Models of power systems and test power electric systems. Tht5e dynamic and static models of the elements of power systems, such as generatorbbs, AVRs, PSSs, loads and FACTS controllers are presented. Method of power system linearization modeling is introduced. Three test power systems, WSCC 9-bus system, 2-area system, New England 39-bus system, are used in thesis.<p>
ï¼ 2ï¼ Multi-objective optimizations based on bifurcation theory. The optimization models, damping control-Hopf bifurcation control, voltage control-damping control, are presented. Pareto combined with evolutionary strategy (ES) are used to solve multi-objective optimizations. Based on traditional PSS parameters optimizations, it can be formulated as a multi-objective problem, in which, two objectives should be taken into account. The minimum damping torque should be identified.<br>Master of Science
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Ibrahim, Awad Ibraik. "An intelligent support system for the analysis of power system transients." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0021/NQ56562.pdf.
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Kazazoglu, Renan. "The Global Navigation System Scope (GNSScope) : a toolbox for the end-to-end modelling simulation and analysis of GNSS." Thesis, University of Westminster, 2010. https://westminsterresearch.westminster.ac.uk/item/90679/the-global-navigation-system-scope-gnsscope-a-toolbox-for-the-end-to-end-modelling-simulation-and-analysis-of-gnss.
Full textAbstract:
The thesis provides a detailed overview of the work carried out by the author over the course of the research for the award of the degree of Doctor of Philosophy at the University of Westminster, and the performance results of the novel techniques introduced into the literature. The outcome of the work is collectively referred to as the Global Navigation System Scope (GNSScope) Toolbox, offering a complete, fully reconfigurable platform for the end-to-end modeling, simulation and analysis of satellite navigation signals and systems, covering the signal acquisition, tracking, and range processing operations that take place in a generic Global Navigation Satellite System (GNSS) receiver, accompanied by a Graphical User Interface (GUI) providing access to all the techniques available in the toolbox. Designed and implemented entirely in the MATLAB mathematical programming environment using Software Defined Radio (SDR) receiver techniques, the toolbox offers a novel new acquisition algorithm capable of handling all Phase-Shift Keying (PSK) type modulations used on all frequency bands in currently available satellite navigation signals, including all sub-classes of the Binary Offset Carrier (BOC) modulated signals. In order to be able to process all these signals identified by the acquisition search, a novel tracking algorithm was also designed and implemented into the toolbox to track and decode all acquired satellite signals, including those currently intended to be used in future navigation systems, such as the Galileo test signals transmitted by the GIOVE satellites orbiting the Earth. In addition to the developed receiver toolbox, three novel algorithms were also designed to handle weak signals, multipath, and multiple access interference in GNSScope. The Mirrored Channel Mitigation Technique, based on the successive and parallel interference cancellation techniques, reduces the hardware complexity of the interference mitigation process by utilizing the local code and carrier replicas generated in the tracking channels, resulting in a reduction in hardware resources proportional to the number of received strong signals. The Trigonometric Interference Cancellation Technique, used in cross-correlation interference mitigation, exploits the underlying mathematical expressions to simplify the interference removal process, resulting in reduced complexity and execution times by reducing the number of operations by 25% per tracking channel. The Split Chip Summation Technique, based on the binary valued signal modulation compression technique, enhances the amount of information captured from compressing the signal to reveal specific filtering effects on the positive and negative polarity chips of the spreading code. Simulation case studies generated entirely using the GNSScope toolbox will be used throughout the thesis to demonstrate the effectiveness of the novel techniques developed over the course of the research, and the results will be compared to those obtained from other techniques reported in the literature.
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Ma, Anthony Winston. "Modeling and Analysis of a Photovoltaic System with a Distributed Energy Storage System." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/727.
Full textAbstract:
As California continues to integrate more renewable energy into its electrical system, the state has experienced a corresponding rise in photovoltaic system installations. PV arrays are a unique source of power generation in that they are affected by the location of the sun, shading, and temperature changes. These characteristics make solar one of the most highly variable forms of renewable energy. In order to improve solar power’s consistency, PV systems require a supplemental source of power. The primary focus of this paper is to determine if distributed energy storage systems can be used to reduce the effect of solar intermittency. This paper examines the test data and system specifications of an experimental DESS. The benefits of using a DESS in a PV system are further studied using computer simulation modeling. This paper also shows through computer simulations how a maximum power point tracker can increase a PV array’s power output. The results of this thesis demonstrate that DESS’s are capable of smoothing out highly variable load profiles caused by intermittent solar power.
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Domínguez, García José Luis. "Analysis of the contribution of wind power plants to damp power system oscillations." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/129687.
Full textAbstract:
Wind power has emerged as one of the most promising renewable energy sources. The very penetration levels of wind energy in power systems have altered several aspects of power system operation, such as system stability. Owing to the large penetration of wind power, transmission system operators (TSOs) have established special grid codes for wind farms connection. These grid codes require wind farms to provide ancillary services to the grid such as frequency and voltage regulation. In the near future, the capability of damping power system oscillations will be required. As a result of the development of such requirements, the concept of wind power plant (WPP) arises being de ned as a wind farm which is expected to behave similarly to a conventional power plant in terms of power generation, control and
ancillary services.
As future grid codes will require power oscillation damping contribution from wind power, the thesis is mainly focused on the analysis of the power system stabilizer (PSS) capability of wind power plants. The change produced by wind power plants based on di erent wind turbine technologies on power system small signal dynamics is analysed to determine their possible contribution to damp oscillations. The eff ect of the distance from the tie line to the wind power plant on the controller response and the influence of wind power plants proximity to synchronous generators are demonstrated to be critical factors. At this point several questions are raised as: What are the most critical factors? How can be ensure a proper contribution, at least the best possible response? Can it be ensured to be independent to
the power system and the controller selected?
To answer these questions, this thesis conducts research on proper selection of input-output signal pairs to damp out electromechanical oscillations using wind power plants without drawing attention to a particular control design. This is necessary conclusions about the power system independently of a particular controller. The capability to damp is an intrinsic characteristic of the system and should not be a ected by a particular controller (PSS).
Firstly, di erent analysis techniques are compared, considering both controllability and observability measures and input-output interactions. This enables recommendations to be drawn so as to the selection of the the best signal pairs to damp power system oscillations considering di erent approaches, such as single-input single-output (SISO) and multivariable control (MIMO). Second, a new criterion to select the best input-output signals used by a PSS based on WPPs is presented, considering explicitly local and remote signals in the analysis. Taking into account fundamental design limitations and using controllability and observability concepts, the criterion is able to identify the most suitable pair of input-output local signals without consider any particular controller. Finally, due to the increase of wind power generation - including o shore locations - and the concept of an interconnected Pan-European network, a new o shore wind power plant AC network similar in design to the European SuperGrid \SuperNode", is analyzed. The cost e ect of choosing a nonstandard operating frequency on the o shore AC network is investigated. As the o shore AC network is isolated from onshore networks through the use of HVDC links, it may be operated in an asynchronous fashion and at a suitable frequency. The cost associated with operating the network at a fixed frequency in the range 20 to 120 Hz is investigated, focusing on the frequency-cost-scalings of electrical devices (such as cables, transformers and reactive compensation) and the related o shore infrastructures,<br>L'energia e olica s'ha convertit en una de les fonts d'energia renovable m es prometedores. Actualment, l'elevat nivell de penetraci o de l'energia e olica a la xarxa el ectrica ha conduï t a la modi caci o del comportament de diversos aspectes d'aquesta, com per exemple, l'estabilitat. Degut a aquesta gran penetraci o, els operadors de xarxes de transmissi o (TSOs) han establert procediments d'operaci o especials per a la connexi o de grans parcs e olics. Aquests codis requereixen als parcs elics que realitzin serveis auxiliars al sistema el ectric com, per exemple, la regulaci o de freqü encia i la regulaci o de la pot encia reactiva. En un futur proper, la capacitat dels parcs e olics per
esmorteir les oscil lacions del sistema de pot encia es requerir a (en l'actualitat ja existeixen esborranys de nous procediments d'operaci o que ho inclouen).
A causa d'aquest requeriments, el concepte de central de generaci o d'energia e olica es de neix com un parc e olic que s'espera que es comporti de manera similar a una central de generaci o el ectrica convencional en termes de poder realitzar tasques tals com generaci o, control i serveis auxiliars. Ja que un futur requeriment dels operadors de xarxa ser a la contribuci o de l'energia e olica en l'esmorteiment de les oscil lacions de pot encia, en aquesta tesi s'estudia la capacitat de les centrals e oliques per actuar com estabilitzador dels sistemes el ectrics de pot encia. A m es a m es, s'analitza l'efecte de les centrals d'energia e olica al comportament din amic del sistema el ectric considerant l'estabilitat de petita senyal, per a determinar quina podr a ser la possible contribuci o proporcionada per aquestes tecnologies. S'ha estudiat
que l'efecte de la dist ancia des d'el punt de connexi o amb la central d'energia e olica a la resposta del control estabilitzant i la influ encia de la proximitat de les centrals e oliques als generadors s ncrons s on factors cr tics. D'aquest fet surgeixen algunes preguntes com: Es aquest el factor m es cr tic? Com es pot assegurar una contribuci o adequada, si m es no la millor resposta possible, per ajudar a estabilitzar el sistema el ectric? Es poden asegurar quina ser a la contribuci o a l'estabilitat del sistema el ectric independentment de la xarxa i l'esquema de control escollit?
Per respondre a aquestes preguntes, aquesta tesi ha realitzat investigacions sobre l'adequada selecci o de parells de senyals d'entrada-sortida per esmorteir les oscil lacions electromec aniques amb centrals e oliques evitant dissenyar el controlador i propossant met odes f acilment adaptables a qualsevol sistema el ectric. En primer lloc, s'han comparat diferents t ecniques d'an alisi tenint en compte tant les mesures de controlabilitat i observabilitat com les interaccions entre les senyals d'entrada i sortida. D'aquesta comparaci o, certes recomanacions es donen a l'hora de seleccionar els millors parells de senyals per esmorteir les oscil lacions del sistema el ectric de pot encia considerant diferents esquemes de control com ara entrada unica sortida unica (SISO) i control multivariable (MIMO). En segon lloc, s'ha proposat un nou criteri per seleccionar les senyals d'entrada i sortida utilitzades per un control estabilitzador per centrals d'energia e olica. On, a difer encia amb anteriors met odes de selecci o proposats, el criteri presentat considera expl citament tant senyals locals com senyals remotes dins el seu an alisi. Aquest criteri es capa c d'identi car la parella de senyals locals d'entrada i sortida m es adequada sense realitzar el disseny del controlador, considerant tant les limitacions fonamentals del disseny del controlador imposades per el sistema com els conceptes de controlabilitat i observabilitat.
Finalment, a causa del augment de la generaci o d'energia e olica, principalment en localitzacions marines, i al concepte d'una xarxa el ectrica comuna Pan-Europea, s'ha realitzat l'an alisi d'un nou concepte de xarxa en corrent altern (AC) dins de les centrals d'energia e olica marina, amb un disseny similar al concepte investigat a la Super-Xarxa Europea \Supernode". En aquest treball s'ha investigat l'efecte que t e en els costos la tria una freqüencia nominal d'operaci o no est andard en dita xarxa en corrent altern. La xarxa en AC que es forma entre les turbines e oliques i el convertidor de transmissi o es aï llada tant de les xarxes terrestres per l' us d'enlla cos en corrent continu (HVDC) com de la pr opia de les turbines per el convertidor que porten incorporat. Aquest fet implica que aquesta xarxa pot ser operada sense sincronitzar
a qualsevol freqüencia.
En aquesta tesi, s'ha estudiat quin es el cost associat amb l'operaci o de la xarxa a una freqü encia fi xa dins del rang de 20-120 Hz, focalitzant principalment en l'escalat del costos dels diferents elements el ectrics (com ara cables, transformadors i compensaci o reatviva i
infraestructures necessaris en instal lacions marines respecte la freqüencia.
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Boesak, Dawid John Johannes. "Voltage stability analysis of a power system network comprising a nuclear power plant." Master's thesis, Faculty of Engineering and the Built Environment, 2018. http://hdl.handle.net/11427/30056.
Full textAbstract:
As recently as 2016, the performance of South Africa’s power utility has shown that it is not resilient enough to withstand the consequences of a power system blackout. Blackouts are defined as being a form of power system instability that can be brought about by a variety of abnormal network scenarios. The most common modes of failure are grouped under the term power system stability. In this dissertation, the different modes of power stability that can affect a nuclear power station will be investigated and discussed. The particular phenomenon that will be focused on, however, is the effect that voltage instability has on the ability of generators and loads to perform their standard functions, thus ensuring a secure power system. To investigate the effect that voltage instability has on a nuclear power station, this dissertation will look at relevant literature on the topic. In addition, by extracting from common examples of national and international occurrences of voltage stability, this dissertation will record the effects that this phenomenon has on the security of a power system, in particular on nuclear power plants. To model the network containing a nuclear power plant for the evaluation of voltage stability, the different mathematical models of the generation plant are presented, which include: the automatic voltage regulator, power system stabilizer, governor, nuclear reactor, and excitation system. Also presented are mathematical models of network equipment such as under voltage tap changers and the dynamic loads that are of interest when evaluating voltage stability. The models used for evaluation of the voltage stability phenomenon affecting a nuclear power plant and the surrounding integrated power system are built in the Digsilent PowerFactory® software. The scenario for evaluation is based on a voltage stability event that occurred around at the Koeberg nuclear power system situated in the Western Cape province on South Africa on 15 October 2003. It is commonly accepted that voltage stability can be evaluated at a steady state level by performing power versus voltage (PV) analysis to determine the voltage buses vulnerable to voltage collapse, and reactive power versus voltage (QV) analysis to determine the critical reactive devices required to avert a voltage instability event. The scenarios that are evaluated for voltage stability are divided into two sections: i) a PV and QV analysis as per the event that occurred on 15 October 2003 and ii) present-day voltage stability indices for PV and QV if mixed with a generation such as renewable energy sources that include wind, solar, biomass and concentrated solar power (CSPs). The result reveals the vulnerabilities of the nuclear power plant and the surrounding integrated power system due to a voltage instability event. Some of the solutions proposed include a review of the typical power system protection schemes — such as under and overvoltage detection scheme — that are used. In the study, PV and QV curves provide v good indications of the state of critical busbars and the reactive power reserve margins available before instability can potentially settle in. Simulations confirmed the effectiveness of critical equipment installed in the Western Grid and the effect on their electrical parameters such as torque and the slip on motors.
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Holthe, Alexander Håkan George. "Analysis of a Multi-Infeed HVDC System in the Norwegian Power System." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26982.
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The impact of a new Modular Multi-Level Converter (MMC) on a Line Commutated Converter (LCC) in the same AC-grid, representing the future system of NordLink and NorNed is investigated. This multi-infeed HVDC system is compared against today's LCC stand alone system. A method for detecting commutation failure is proposed. The commutation failure immunity index is 36% and 28% respectively. The result indicate that the MMC-link hence mitigates the weakness of the LCC-link, and makes the LCC inverter less prone to commutation failure. The multi-infeed HVDC system is analysed in both steady and transient state. The MMC is able to control the active and reactive power, and enhances AC voltage regulation. Existing voltage supporting equipment can thus be utilized for a more continuous voltage regulation when the new MMC-link is connected, and to minimize losses. Single and three phase to ground faults are applied. The results indicate that a LCC inverter in weak AC grids may suffer from commutation failure. The MMC is able to ride through relatively severe AC faults. The results indicates that the multi-infeed system improves the performance when AC faults are applied as compared the existing LCC stand alone system. The MMC-link is able to mitigate the impact of AC faults, thus helping the LCC-link recover faster. The coupling effect between AC and DC overhead lines sharing the same Rights-of-Way is investigated, and a single pole to ground fault is applied. Induced DC currents into AC lines are detected. The peak rms neutral current in the AC lines is found to be 1000 A for fault location close to MMC inverter. Two mitigation methods are proposed. First, an optimal displacement of the middle AC tower is found to be 45 meters apart from the DC tower, and leads to a reduction of 22.3% (777 A). Second, transposition of the AC-lines efficiently reduced the coupling effect, as it averages the unbalance between the three phases.
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Alsenani, Theyab R. "Power System Repair and Restoration Optimisation." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23493.
Full textAbstract:
This thesis contributes to the power system restoration (PSR) field by studying (in the aim of improving) the power system repair and restoration (PSRR) which is a novel problem in PSR. The optimisation concept was our approach and mechanism in tackling this topic. The thesis provides a basic contribution to the PSRR field by studying some of its main subjects and presenting improvements to the best practices in the field. This thesis is built on five research papers related to the thesis title. The thesis investigated a large number of high-quality published research papers, and presented a novel, precise, and comprehensive overview of the topic that could be considered a good introduction for anyone who would like to learn the topic. This was presented in chapter two. We have presented a well-developed and easy to understand structure that starts from the basics of PSR and PSRR to their details and relevant subjects. Also, in this thesis we provided application-based studies using mathematical optimisation techniques, where we model a specific power system then solve the PSRR problem aiming optimality. Different optimisation techniques were applied, analysed, and compared for both sides of the problem (i.e. the restoration problem, and the repair problem) as well as different modelling for power systems. Our findings in this chapter were interesting and align with other high-quality studies in the literature. This was presented in details in chapter three. This thesis also tackled a very important relevant subject which is the system reliability under certain restoration scenarios. Where we studied the effects of restoration actions under certain conditions such as cold load pickup events to the reliability indices of the system. A novel Nature-inspired optimisation technique was developed and compared to an old technique that was presented in a high-quality study in the literature. This was presented in chapter four. We concluded this thesis research by developing a statistical analysis for power system outages for a decade period of time in the Australian industry as well as investigating the potential benefits of smart grid technologies and their investments to the power grid. Many statistical methods were applied and investigated using state-of-the-art programming tools. This was presented in chapter five. We have presented very interesting results and findings in this chapter.
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Olofsson, Magnus. "Power Flow Analysis of the Swedish Railway Electrical System." Licentiate thesis, Stockholm, 1993. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-223934.
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This thesis deals with analysis of the steady state power flow in the Swedish railway electrical system. Finding the steady state of the system means that all voltages and power flows in the system are known. The trains are supplied from the public grid using frequency converters. This is the major difference compared with ordinary power systems fed from turbine-driven generators. The output voltage phase shift function for the converters is important in the mathematical formulation of the problem. In the system, the locomotives are almost entirely of the Re-type, having a rectifier and d.c.-motors. The fundamental frequency reactive power need is thereby dependent on the train speed, wheel power and line voltage. In this thesis, the converters and thyristor locomotives are modelled and included in the load flow formulation. The method is shown to have good convergence properties. An approximate and fast method for the calculation of the power injections from converters is presented. A necessary condition for this approximate method to be valid is that the converters are strongly interconnected. The construction of a new 130 kV line brings the converters close to each other electrically. Energy input from each of the converters inthe system can be simulated calculating repeated load flows. Measurements in a real system have verified the applicability of the proposed load flow method. Examples of areas where the method can be used are system studies and optimal control of the system. The locomotives act as sources of harmonic currents. In an extended load flow formulation this is taken into account. The fundamental idea behind the method is that harmonic powers caused by the thyristor bridges at first are transferred as fundamental frequency active power from the sinusoidal voltage sources. The method thus gives the fundamental frequency powers injected from the sinusoidal voltage sources to the network. Comparisons with time simulations with detailed models show good agreement.
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Bocancea, Emanuel. "Data acquisition and analysis system for power electronic circuits." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq22575.pdf.
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Deese, Anthony Steven Nwankpa Chika O. "Analog methods for power system analysis and load modeling /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2822.
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Ahmad, M. Masood. "Sensitivity estimates via perturbation analysis in power system simulations." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/15408.
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Scheidiger, Michael. "Power System Harmonics Analysis of HighPower Variable Speed Drives." Thesis, KTH, Elektrisk energiomvandling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-153676.
Full textAbstract:
Power system harmonics are a topic of significant concern when considering power quality issues in systems containing Variable Speed Drives. The extent to which grid-connected power electronics based motor drives affect power quality is tightly enforced through standards, and must be adhered to. To ensure compliance, harmonic models of Variable Speed Drives and relevant components of the connected power system are evaluated. When necessary, analysis results can be used to aid the design of additional harmonic mitigation measures. Harmonic assessments are most commonly carried out using time-domain models. This thesis details the fundamentals of harmonic assessment and mitigation measure design. Matlab implementations of those fundamentals are discussed, with comments regarding the accuracy and limitations of each. State of the art analytical harmonic models for Voltage Source Variable Speed Drives are analyzed and compared, from which a new model for 3-level inverter Variable Speed Drives is proposed. The new model can be implemented in any numerical computing environment and is thought to generate a harmonic current spectrum for an approximate judgement of harmonic compliance based on the current injection method.<br>Övertoner i kraftsystem innehållande frekvensomriktare är ett viktigt ämne när el-kvalité behandlas. Den grad nätanslutna elektroniska motorsystem påverkar el-kvalitén är noggrant upprätthållen av standarder och måste följas därefter. För att säkerställa att standarder upprätthålls utvärderas modeller för frekvensomriktare och relevanta komponenter. När det anses nödvändigt kan resultaten vara vägledande för design av ytterligare övertonsminskande åtgärder. Utvärdering av övertoner görs i allmänhet med hjälp av modeller i tidsdomän. Denna uppsats går igenom grunderna för bedömning av övertoner och design av övertonsminskande åtgärder. Matlab-modeller av dessa diskuteras i termer av precision och begränsningar. De främsta analytiska modeller for frekvensomriktare undersöks och jämförs, varefter en ny modell av en växelriktare med 3 nivåer föreslås. Denna modell kan med enkelhet implementeras i numeriska datormiljöer och framställer ett frekvensspektrum av strömmen för en approximativ bedömning av el-kvalité baserad på ströminmatningsmetoden.
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MANSO, LUIZ ANTONIO DA FONSECA. "POWER SYSTEM ANALYSIS THROUGH INTERACTIVE ALGORITHMS FOR PERSONAL COMPUTERS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1989. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9399@1.
Full textAbstract:
O presente trabalho de dissertação de mestrado tem por
finalidade contribuir para uma maior dinamização do
ensino de engenharia de sistemas de potência através da
elaboração de um conjunto de algoritmos interativos para
microcomputadores, onde o aluno poderá realizar um
processo contínuo de experimentação, questionamento e
revisão de conceitos.
Para um bom desenvolvimento deste processo de
aprendizagem
é criado um ambiente amigável onde o usuário tem suas
ações amparadas por mensagens explicativas e de
monitoração de erros, resultando na redução do tempo
gasto
em cada seção de estudo e estimulando o mesmo a realizar
um número maior de simulações.
Foram elaboradas quatro programas de computadores. O
primeiro, responsável pela estrutura conversacional e
gerenciamento, foi escrito em PASCAL. Os demais foram
escritos em FORTRAN77 e se restringem à execução dos
cálculos necessários aos estudos de: fluxo de potência,
curto-circuito e estabilidade transitória. Estes três
últimos programas utilizam técnicas especiais para
armazenagem de matrizes esparsas e obtenção do elementos
de interesse de suas inversas.
Três sistemas de potência foram escolhidos para estar
imediatamente disponíveis ao usuário, sendo que um deles
é
utilizado no texto durante a explanação da estrutura
conversacional para os estudos disponíveis.<br>The present Dissertation aims to provide more dynamism to
the teaching and learning process in power system
engineering through a set of interactive personal computer
algorithms. The student may carry out a continuous process
of experimenting, questioning and revision of concepts.
In order to better develop the leaining process, a frindly
environment is created where the user has his actions
supported by explanatory and error monitoring messages.
This results in a reduction of the time spent in each
study section and, consequently, it estimulates the
student to perform a greater number of simulations.
Four computer programs have been developed. There
is one written in PASCAL language, responsible for the
following studies: load flow, slort-circuit and transient
stability. These programs use special sparsity techniques
and programming.
Three power systems have been choosen to be
immediately available to the user. One of them is used in
the text during the explanation process of the
conversational structure of the power system studies.
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Naidoo, Throshni. "The development of a behavioural video analysis system and a toolbox prototype." Thesis, 1996. http://hdl.handle.net/10413/5910.
Full textAbstract:
Behavioural research studies often include a data acquisition process, during which
subjects are observed, and the displayed behaviours recorded, and a subsequent analysis
process, during which the observed behaviours are analysed. In addition the data
acquisition process could occur in real-time, or at a later stage, by referring to a recording
of the original session.
This dissertation addresses the latter approach through the use of computer based digital
video technology. A windows based video analysis system, called VAS, that was
developed to assist with the acquisition of observed behaviours from the video, and the
analysis thereof is discussed. This is followed by a discussion of the implementation of
VAS. Finally the directions for further research are identified, and discussed.<br>Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.
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林士煜. "Power system harmonic analysis." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/80403314004726205987.
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Reddy, C. M. "Power System Voltage Stability Analysis." Thesis, 2011. http://raiith.iith.ac.in/662/1/EE09G003.pdf.
Full textAbstract:
Power system is facing new challenges as the present system is subjected to severely
stressed conditions. Voltage instability is a quite frequent phenomenon under such a
situation rendering degradation of power system performance. In order to avoid system
blackouts, power system is to be analyzed in view of voltage stability for a wide range of
system conditions.
In voltage stability analysis, the main objective is to identify the system maximum
loadability limit and causes of voltage instability. Static voltage stability analysis with
some approximations gives this information. Voltage stability problem is related to load
dynamics and therefore dierent load characteristics are to be considered in the voltage
stability analysis.
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Tseng, Shang-Ren, and 曾上仁. "Power System Contingency Analysis by Power-Voltage Curve." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/76630173172664947369.
Full textAbstract:
碩士<br>國立臺灣海洋大學<br>電機工程學系<br>96<br>Voltage instability of power system is mainly caused by large amount of increase in load demand, yielding drops in the bus voltage which, if out of control, may lead to contingencies with voltage collapse.
The main objective of this thesis is to analyze power system voltage stability by using both P-V Curve and Q-V Curve. In static analysis, the P-V Curve will denote the point of voltage collapse and the maximum transmission power limit can be obtained, and Q-V Curve can identify the voltage stability limit and can reveal the robustness of the power network. As for dynamic analysis, time domain dynamic responses are investigated in the study of voltage stability. Comparisons are made with the results obtained from static and dynamic analyses. Moreover, case studies associated with some contingencies are conducted for examining the resultant impact on power system voltage stability.
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Wu, Chien-Liang, and 吳建良. "Power system Load Flow and Power Factor Improvement Analysis." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/05678667082150156149.
Full textAbstract:
碩士<br>和春技術學院<br>電機工程系碩士班<br>100<br>Electric power systems play a very important role in our daily life. The Generating system provides us electric power, and the transmission system is responsible for distributing the electric power everywhere. Furthermore, The distribution system relocates the power to various users. However, during the process of the power distribution, the quality of the electric power will be affected by the all kinds of the equipment or the distributing systems. Owing to the issue, we will discuss the problems based on the analysis of the load characteristics. First of all, we make of Model 7, 22 and 35 which are small, medium and the large-scale bus, using the CYME electrical power system simulator by Gauss-seidel method, the Fast Decoupled bus voltage size and phase angle change, and active power, reactive power and line losses. We also take advantages of uses in CYME to construct Static Var Compensator, compensate system on reactive power, improved power factor, reduction system loss, and aims to install the position and setting of the parameters, and to discuss the systematic change after installing around SVC. In addition, when the system revolution arise fault, we analyze the different types of the short circuit faults. Moreover, once faults occur, it will compute system's various buses voltage and electric current size.
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Zhang, Zhonghua. "Algorithms for power system security analysis." 1999. http://hdl.handle.net/1993/2298.
Full textAbstract:
This thesis analyses the transient stability calculation tools for power system dynamic security assessment. It gives basic implementation of common transient energy function methods: Extended Equal Area Criterion method, Relative Unstable Equilibrium Point method, Potential Energy Boundary Surface method. Assumptions for these methods and their affect on the accuracy are given. Detailed theoretical analysis, algorithms, and sensitivity analysis are presented for each method. Applications of these methods on two sample systems are performed and results are obtained.
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Chen, Ying-Wang, and 陳應望. "Cluster Analysis of Power System Coherency." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/35901276080079823297.
Full textAbstract:
碩士<br>國立海洋大學<br>電子工程學系<br>83<br>With the increasing size of interconnected power systems,power
system dynamics study has been becoming more complex.
Methods of coherency-based dynamic equivalencing have been
proposed to reduce the computational effort required in power
system dynamics study. The key step in the construction of
coherency-based dynamic equivalents is the identification of
coherent generators. A useful application of fuzzy mathematics
is the hierachical clustering whose correctness depends on
the computation of the fuzzy transitive closure. The objective
of this thesis is to develop an efficient hierarchical
clustering method suitable for the identification of coherent
generators in power systems. This method is based on the
concept of similarity relation and the technique of
hierarchical cluster analysis.This hierarchical structure
depicts the generator clustering at different level of
coherency, and from which appropriate number of coherent
groups can be determined according to the need for
reduction in model complexity.
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Hsieh, Chi-Hao, and 謝其浩. "Nanosat power system planning and analysis." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/50272426659053957996.
Full textAbstract:
碩士<br>國立中央大學<br>機械工程研究所<br>90<br>The goal of this thesis is design a power system to fit the Nanosat use to reach the mission requirement. The weight of Nanosat is 10 kilograms, sun-synchronous circular orbit, orbit altitude is 800 km, orbit inclination is 98.6 degree, orbit period is 101 minutes. The main mission is atmosphere observation and GPS positioning.
In this project, we’ll introduce the solar arrays planning and the battery charge/discharge designing. Make a power summary table for each mission mode. We know the total power we need is 20 W, maximum eclipse period is 35 minutes, solar arrays effective area is 0.3029 m2, the depth of discharge of battery is 20.4 %, charge current is 1.035 A, complete charge time is 1.096 hr.
The power circuit system including DC-DC converter, diode, current sense, voltage sense, temperature sense, switch component etc. According to the component and system test to ensure the system will be fine. Conduct trade studies in search of design improvements and duty cycle analysis. Refine the power summary table.
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HUANG, ZHONG-GING, and 黃鐘慶. "Long-term power system dynamic analysis." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/32645466904050563900.
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Zheng, Yu Yao, and 鄭宇堯. "Power System Analysis of Cogeneration Plant." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/37447897136032786559.
Full textAbstract:
碩士<br>長庚大學<br>電機工程學系<br>98<br>This thesis focuses on the power system analysis of an actual cogeneration plant. The analysis includes power flow calculation, short-circuit current analysis, transient stability evaluation, and voltage sag analysis. First, the system structure of the plant including synchronous generators, induction motors, and transformers are built. The power flow analysis ensures that all equipments are operated under their rated capacities in all possible situations. The short circuit analysis identifies that the fault currents on each bus are within their momentary and interrupting withstanding levels. The transient stability analysis evaluates that the cogeneration plant can recovery from utility faults and possible grid-disconnection behaviors. The voltage sag analysis ensures that sensitive loads in the plant won’t trip because of faults. The above analysis results can provide field personnel with useful information to enhance the overall operation reliability of the plant.
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Chu, Chih-Tsung, and 朱志琮. "Power System Inter-area Mode Analysis." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/59879372002730433355.
Full textAbstract:
碩士<br>國立臺灣海洋大學<br>電機工程學系<br>94<br>Abstract
The main purpose of this thesis is to study the inter-area oscillation mode in power systems, with the application of remote synchronized phasor measurements to the improvement of overall system stability. In this thesis, the corresponding eigenstructure of the inter-area modes of both a two-area-four-generator power system and a large scale power system are investigated in details. Various factors in the design of power system stabilizers, including installation site, signal selection and signal delay, are examined to analyze their effects on system stability and to verify the feasibility the designed power system stabilizers.
Keywords: Inter-area Oscillation Mode, Power System Stabilizer (PSS), Phasor Measurement Unit (PMU).
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WANG, LI, and 王醴. "Analysis of power system dynamic stability." Thesis, 1988. http://ndltd.ncl.edu.tw/handle/45625016847724142637.
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林士傑. "Analysis of Marine Electric Power System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/25497736170299086903.
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