Dissertations / Theses on the topic 'Thyrister control'
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張華 and Hua Zhang. "Digital vector control of forced-commutated cycloconverter drives." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B31234574.
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Zhang, Hua. "Digital vector control of forced-commutated cycloconverter drives /." [Hong Kong] : University of Hong Kong, 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1594847X.
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Fan, Lingling. "Robust decentralized control of power systems through excitation systems and thyristor controlled series capacitors." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2242.
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Thesis (Ph. D.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains x, 121 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 99-103).
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Ängquist, Lennart. "Synchronous Voltage Reversal Control of Thyristor Controlled Series Capacitor." Doctoral thesis, KTH, Electrical Systems, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3396.
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Series compensation of transmission lines is an effectiveand cheap method of improving the power transmission systemperformance. Series capacitors virtually reduces the length ofthe line making it easier to keep all parts of the power systemrunning in synchronism and to maintain a constant voltage levelthroughout the system. In Sweden this technology has been inuse since almost 50 years.
The possibility to improve the performance of the ACtransmission system utilizing power electronic equipment hasbeen discussed a lot since about ten years. Some newsemiconductor based concepts have been developed beside thesince long established HVDC and SVC technologies. The ThyristorControlled Series Capacitor (TCSC) is one such concept. Byvarying the inserted reactance an immediate and well-definedimpact on the active power flow in the transmission line isobtained. Several potential applications, specifically poweroscillation damping, benefit from this capability. The conceptimplied the requirement to design a semiconductor valve, whichcan be inserted directly in the high-voltage power circuit.This certainly presented a technical challenge but thestraightforward approach appeared to be a cost-effectivealternative with small losses.
It was also realized that the TCSC exhibits quite differentbehaviour with respect to subsynchronous frequency componentsin the line current as compared to the fixed series capacitorbank. This was a very interesting aspect as the risk ofsubsynchronous resonance (SSR), which just involves such linecurrent components, has hampered the use of series compensationin power systems using thermal generating plants.
The thesis deals with the modelling and control aspects ofTCSC. A simplifying concept, the equivalent, instantaneousvoltage reversal, is introduced to represent the action of thethyristor controlled inductive branch, which is connected inparallel with the series capacitor bank in the TCSC. The idealvoltage reversal is used in the thesis in order to describe andexplain the TCSC dynamics, to investigate its apparentimpedance at various frequencies, as a platform forsynthesizing the boost control system and as the base elementin deriving a linear, small-signal dynamical model of thethree-phase TCSC. Quantitative Feedback Theory (QFT) then hasbeen applied to the TCSC model in order to tune its boostregulator taking into account the typical variation ofparameters that exists in a power system. The impact of theboost control system with respect to damping of SSR is finallybeing briefly looked at.
Keywords:Thyristor Controlled Series Capacitor, TCSC,FACTS, reactive power compensation, boost control, phasorestimation, Quantitative Feedback Theory, subsynchronousresonance, SSR.
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Genc, Murat. "Design And Digital Implementation Of Thyristor Controlled Reactor Control." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12609184/index.pdf.
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In this research work, the control system of 16 MVAr, 13.8 kV TCR will be
designed and digitally implemented. A Real-Time Control System (NI
CompactRIOTM Reconfigurable I/O) and a Digital Platform (NI LabVIEWTM Gcode)
are used in the digital implementation of TCR control system. The digital
control system is composed of reactive power calculation, firing angle
determination and triggering pulse generation blocks. The performance of control
system will be tested in the field. The simulation results will also be compared
with test data.
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Kite, David John. "Improved current control in thyristor drives for d.c. machines." Thesis, University of Bath, 1985. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.767552.
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The accurate and versatile control of a direct current machine's speed using a thyristor converter has led to its use for many industrial applications. However, as will be demonstrated, the current gain characteristic of such a device is not linear and under certain operating conditions can lead to an unacceptable degradation in performance. In order to develop a method of adaptive control that can compensate for the gain changes, the key features and theory of phase controlled thyristor converters are described and used to develop a digital computer simulation of a single phase converter. The d.c. gain of the device as a function of firing angle is then determined and the model used as the basis of a larger simulation of the machine's armature current control loop. The latter is used to investigate a number of control strategies, one of which is developed practically using a combination of analogue and digital electronics. The performance of the adaptive control system is then investigated by means of a comparison with the responses predicted by the software model and also by comparing the responses of the adaptive controller with the current loop responses obtained from a purely linear commercial drive. These show that the implementation of the chosen control strategy, although being very complex, does not achieve ideal responses. However, those obtained are seen under most conditions to be an improvement on the conventional system. Finally, the effect of the different armature current controllers on the speed response of d.c. machines using both linear and variable structure speed controllers is investigated. This is done purely in software following the development of a digital simulation of the speed loop. These show the adaptive qualities of VSS speed control, especially when used with the "faster" adapted current loop.
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Barnes, M. J. "The prediction and control of transients in thyristor valves." Thesis, Aston University, 1985. http://publications.aston.ac.uk/15140/.
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This thesis describes an investigation of methods by which both repetitive and non-repetitive electrical transients in an HVDC converter station may be controlled for minimum overall cost. Several methods of inrush control are proposed and studied. The preferred method, whose development is reported in this thesis, would utilize two magnetic materials, one of which is assumed to be lossless and the other has controlled eddy-current losses. Mathematical studies are performed to assess the optimum characteristics of these materials, such that inrush current is suitably controlled for a minimum saturation flux requirement. Subsequent evaluation of the cost of hardware and capitalized losses of the proposed inrush control, indicate that a cost reduction of approximately 50% is achieved, in comparison with the inrush control hardware for the Sellindge converter station. Further mathematical studies are carried out to prove the adequacy of the proposed inrush control characteristics for controlling voltage and current transients during both repetitive and non-repetitive operating conditions. The results of these proving studies indicate that no change in the proposed characteristics is required to ensure that integrity of the thyristors is maintained.
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Mahmoud, M. El-S. "A microprocessor thyristor-controlled DC drive incorporating regenerative braking." Thesis, University of Bradford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355222.
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何沛德 and Pui-tak Ho. "Control and operation of high-performance thyristor-controlled-reactor(TCR) compensators." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B31231160.
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Uz, Eda. "Design And Implementation Of Thyristor Switched Shunt Capacitors." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611616/index.pdf.
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This research work deals with the analysis, design and implementation of thyristor switched plain capacitor banks and thyristor switched shunt filter banks. Performances of various thyristor switched capacitor (TSC) topologies are also investigated by simulations. The theoretical findings have been verified by carrying out experimental work on two prototypes implemented within the scope of this research work, one is a wye-connected laboratory prototype and the other is a delta-connected application prototype integrated to some of the SVCs existing in Turkish Coal Enterprise s Plants. The advantages of back-to-back connected thyristor switches over conventional electromechanical contactors are also made clear by conducting an intensive experimental work in the laboratory. A good correlation have been obtained between theoretical and experimental results.
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Smiai, Mohamed Salah. "Speed control of wound-rotor induction motor using thyristors to control rotor external resistance." Thesis, University of Bradford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253409.
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Leung, Chiu Hon. "The output frequency spectrum of a thyristor phase-controlled cycloconverter using digital control techniques." Thesis, University of Plymouth, 1985. http://hdl.handle.net/10026.1/2261.
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The principle of operation dictates that the output of a cycloconverter contains some harmonics. For drive applications, the harmonics at best increase losses in the motor and may well cause instability. Various methods of analysing the output waveform have been considered. A Fortran 77 program employing a modified Fourier series, making use of the fact that the input waveforms are sinusoidal, was used to compute the individual harmonic amplitudes. A six pulse three phase to single phase cycloconverter was built and a Z-80 microprocessor was used for the control of firing angles. Phase locked loops were used for timing, and their effect upon the output with changing input frequency and voltage were established. The experimental waveforms are analysed by a FFT spectrum analyser. The flexibility of the control circuit enables the following investigations not easily carry out using traditional analog control circuit. The phase relationship between the cosine timing and reference wave in the cosinusoidal control method was shown to affect the output waveform and hence the harmonic content. There is no clear optimum value of phase and the T.H.D. up to 500Hz remains virtually constant. However, the changes of individual harmonic amplitudes is quite significant. In practice it may not be possible to keep the value of phase constant but it should be considered when comparing control strategies. Another investigation involves the changing of the last firing angle in a half cycle. It shows that the value of firing angles produced by the cosinusoidal control method is desirable. Operation at theoretical maximum output frequency was also demonstrated.
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Tang, C. K. K. "Performance studies of a thyristor controlled reactor for arc furnace compensation using computer and laboratory models." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381290.
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Johansson, Nicklas. "Control of Dynamically Assisted Phase-shifting Transformers." Licentiate thesis, Stockholm : Elektrotekniska system, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4653.
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Engel, Stefan P. [Verfasser]. "Thyristor-Based High-Power On-Load Tap Changers : Control under Harsh Load Conditions / Stefan P. Engel." Aachen : Shaker, 2017. http://d-nb.info/1124366547/34.
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Poyiadjis, Soteris. "A New Cell Bypass Arrangement and Control for Modular Multilevel Converters based on Thyristor Forced Commutation Circuit." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-201660.
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HVDC transmission lines are a competitive and in some cases are proven to bea superior choice compared to AC transmission applications. Suitable convertershave been developed for that matter where Modulär Multilevel Converters (MMC)are highly preferred due to their low losses, no filtering requirementsand direct andfast control of AC and DC side. However, the overall eciency of the converteris higher than of a six pulse voltage source converter, it is still lower than the linecommutated converter type.In this master thesis an attempt to decrease the conduction losses of the MMC isinvestigated. A new cell structure design used in MMC is proposed along with itsassociated control strategy. The main idea is to divert the current at steady stateoperation through thyristors, which have lower conduction resistance than IGBTsthat are used in MMC topologies, at time intervals where the capacitor is bypassedfrom the cell. This new cell commutation is tested initially in the lab and thenthe whole structure operation is validated on a 3 phase MMC PSCAD model. Theresults from the lab confirmed the commutation of the new cell and the results fromthe 3 phase model showed that the new cell structure does not disturb the normaloperation of the MMC. A rough loss comparison that have been conducted betweenthe new cell structure and a half bridge that is used in a typical MMC, showed thatthe first one was less efficient. For that reason a generalized concept is introducedwhich promise higher efficiency than of the proposed concept.HVDC transmission är ett fördelaktigt sätt att överföra eekt i jämförelse med ACtransmission. Omriktare har utvecklats för att passa applikationen, där ModularMultilevel Converters (MMC) har visat sig passa bra för HVDC på grund av de lågaförlusterna och dess obentliga krav på lter. Dessutom har de en direkt och snabbkontrollteori på både AC och DC sidan. Även om dess totala verkningsgrad är högreän hos six-pulse voltage source converter (VSC) men lägre än Line CommutatedConverter (LCC).Detta exjobb innefattar att minska ledningsförlusterna i MMCn. En ny designav cell strukturen föreslås, tillsammans med en passande kontrollteori. Idén äratt, på grund av dess lägre ledningsresistans använda tyristorer snarare än IGBTervilka annars är vanliga i MMCer, detta då kondensatorn är förbikopplad.. Dennya cellstrukturen testas initialt experimentellt i laboratorium och hela systemetvalideras genom simulering av en 3-fas MMC modell i PSCAD. De experimentellaresultaten bekräftade att den nya modellen fungerar och de simulerade resultatenvisar att den föreslagna topologin inte stör funktionen hos MMCn. En jämförelsemellan den nya topologin och den konventionella halvbridge strukturen har gjorts,där den föreslagna topologin hade lägre verkningsgrad. Istället har en generelltkoncept introducerats för att utlova en högre verkningsgrad än den först föreslagnatopologin.
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Levon, Elena. "Multi-loop Control Systems of Compensators for Powerful Sounding Pulses Generators." Thesis, Institute of Electrical and Electronics Engineers, 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/44052.
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Construction principles of multi-loop control systems of compensators for powerful sounding pulses generators are presented. A method for controlling a compensating system using fuzzy logic and forecast control ideas is described. Proposed compensating system is able to solve different problems: reactive power compensation, harmonic elimination. The system is based on a combination of a thyristor compensator and an active power filter. Some practical results with Matlab-Simulink are presented to check the proposed control performance.
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Sechilariu, Manuela. "Utilisation des réseaux de Petri colorés et temporisés pour la modélisation et la simulation des montages redresseurs et onduleurs." Angers, 1993. http://www.theses.fr/1993ANGE0012.
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Ce mémoire montre la faisabilité d'une technique de commande des convertisseurs statiques, utilisant les réseaux de Petri (RDP). L'originalité de ce travail réside dans l'utilisation de RDP colorés et temporisés pour la modélisation. Deux exemples sont retenus. Le modèle du redresseur triphasé à thyristors est présenté de manière que l'on puisse analyser les valeurs de l'angle de retard d'allumage ; des temporisations de durées variables permettent de simuler la variation de la tension redressée. Le modèle de l'onduleur autonome évolue dynamiquement à la fréquence souhaitée ; le changement de la durée des temporisations associées aux transitions conduit au changement de la fréquence de sortie de l'onduleur. L'étude effectuée sur l'ensemble redresseur-onduleur machine-asynchrone nous permet d'envisager une stratégie de fonctionnement en vitesse de rotation variable, fondée sur une commande algorithmique des temporisations, conformément à l'asservissement donné. Nous avons réalisé une maquette de redresseur à thyristors liée à un ordinateur. La commande est gérée par RDP synchronisé. Elle ouvre des perspectives pour une nouvelle technique de commande des convertisseurs statiques.
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Murray, Nicholas John. "Flexible Power control in Large Power Current Source Conversion." Thesis, University of Canterbury. Electrical and Computer Engineering, 2008. http://hdl.handle.net/10092/2610.
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This thesis describes a new concept, applicable to high-power current-sourced conversion (CSC), where a controllable firing-angle shift is introduced between series and parallel converters to enable independent active and reactive power control. The firing-shift concept solves a difficult problem, by giving thyristor based CSCs the control flexibility of pulse-width modulated (PWM) converters, but without a loss in efficiency or rating. Several configurations are developed, based on the firing-shift concept, and provide flexible, efficient solutions for both very high power HVDC transmission, and very high current industrial processes.
HVDC transmission configurations are first developed for 4-quadrant high-pulse operation, based on the series connected multi-level current reinjection (MLCR) topology. Independent reactive power control between two ends of an HVDC link are proven under firing-shift control, with high-pulse operation, and without on-load tap changing (OLTC) transformers. This is followed by application of firing-shift control to a bi-directional back-to-back HVDC link connecting two weak systems to highlight the added dc voltage control flexibility of the concept.
The fault recovery capability of an MLCR based ultra-HVDC (UHVDC) long distance transmis-sion scheme is also proven under firing-shift control. The scheme responds favourably to both ac disturbances and hard dc faults, without the risk of commutation failures and instability experienced during fault recovery of line-commutated conversion.
The two-quadrant capability of very high current rectification is also proven with configurations based on phase-shifted 12-pulse and MLCR parallel CSCs. The elimination of the electro-mechanical OLTC/satruable reactor voltage control, the high-current CSC’s biggest shortcoming, greatly improves controllability and with firing-shift control, ensures high power-factor for all load conditions. This reduces the reactive power demands on the transmission system, which results in more efficient power delivery
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Johansson, Nicklas. "Aspects on Dynamic Power Flow Controllers and Related Devices for Increased Flexibility in Electric Power Systems." Doctoral thesis, KTH, Elektriska maskiner och effektelektronik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-37823.
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This thesis studies different aspects of Flexible AC Transmission System (FACTS) devices which are used to improve the power transfer capability and increase the controllability in electric power systems. In the thesis, different aspects on the usage and control of Dynamic Power Flow Controllers (DPFC) and related FACTS devices are studied. The DPFC is a combination of a Phase Shifting Transformer (PST) and a Thyristor Switched Series Capacitor (TSSC)/Thyristor Switched Series Reactor (TSSR). The thesis proposes and studies a new method, the Ideal Phase-Shifter (IPS) method, for selection and rating of Power Flow Controllers (PFC) in a power grid. The IPS method, which is based on steady-state calculations, is proposed as a first step in the design process for a PFC. The method uses the Power controller plane, introduced by Brochu et al in 1999. The IPS method extends the usage of decoupling methods in the Power controller plane to a power system of arbitrary size. The IPS method was in the thesis used to compare the ratings of different PFC:s required to improve the power transfer capability in two test systems. The studied devices were here the PST, the TSSC/TSSR and the DPFC. The thesis treats control of ideal Controlled Series Capacitors (CSC), TCSC, TSSC/TSSR, and DPFC. The goals of the FACTS controllers which are developed are Power Oscillation Damping (POD), fast power flow control, and transient stability improvement in the power system. New adaptive control strategies for POD and power flow control are proposed and studied in different models of power systems by time-domain simulations. A strategy for transient stability improvement is also proposed and studied. Additionally, different methods for study of Subsynchronous Resonance (SSR), which is associated with series compensation in power systems, are investigated. Here, four of the most common methods for frequency scanning to determine the electrical damping of subsynchronous oscillations in a power grid are studied. The study reveals significant differences of the electrical damping estimates of the studied standard methods when applied to a four-machine test system.QC 20110819
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Večerník, Jan. "Regulátor pohonu opony." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217701.
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Master's thesis describes and proposes solutions for a given problem of a drive in theater curtain DS Krakonoš - Vysoké nad Jizerou using modern microcontroller with voltage transducer.. There is given a detailed analysis of the problem, including the mathematical description of the entire system, then design and its subsequent implementation. The goal of this work is designed to apply a device designed to the engine, which moves theater curtain.
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Grimoni, Jose Aquiles Baesso. "Análise de compensadores de reativos e simulação ciclo a ciclo de um reator controlado a tiristores." Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-30062017-141238/.
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Este trabalho analisa a necessidade da aplicação dos compensadores estáticos de reativos em sistemas elétricos industriais e em sistemas de potência. Vários tipos de compensadores de reativos são apresentados e também é feita uma comparação entre eles. O trabalho está centralizado no estudo dos compensadores estáticos tiristorisados, principalmente o Reator Controlado a Tiristores (RCT) e o Capacitor Chaveado a Tiristores (CCT). São discutidas as influências de alguns parâmetros nas formas de onda do RCT. É feita a dedução das equações das componentes harmônicas de corrente e tensão do RCT. São também analisados os efeitos das harmônicas e os meios de atenuá-las, de modo a mantê-las dentro de níveis razoáveis. Modelos para a simulação de um RCT, para vários tipos de fenômenos em circuitos monofásicos e trifásicos, são apresentados. São Mostrados gráficos e tabelas de algumas simulações utilizando o programa CSMP (Continuous System Modeling Program) e um programa desenvolvido ciclo a ciclo, utilizando o método passo a passo. As simulações permitem avaliar com razoável precisão o comportamento do RCT associado a um capacitor fixo. Sugestões de estudos afins são apresentadas no final do trabalho.This work analyses the need of using Var systems in industrial and in power electric systems. Various types of VAr systems are presented and also a comparison among them is done. The work is centralized in the study of thyristor static VAr systems. The thyristor controlled reactor (TCR) and the thyristor switched capacitor (TSC) are analysed in more details. Parametric influences in the wave forms of TCR are discussed. TCR voltage and current harmonic equations are deduced. Harmonic effects and also the methods of producing their attenuation are analysed. TCR simulation models for multiple types of phenomena in one phase and three phase circuits are presented. Some graphics and tables using the CSMP (Continuous System Modeling Program), and a cycle by cycle program that uses the step method are showed. The simulations can evaluate with a reasonable precision the behavior of a TCR with a fixed capacitor (FC). Suggestions of other studies are presented at the end of the work.
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Xie, Hailian. "On Power-system Benefits, Main-circuit Design, and Control of StatComs with Energy Storage." Doctoral thesis, Stockholm : Skolan för elektro- och systemteknik, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10302.
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Hadjikypris, Melios. "Supervisory control scheme for FACTS and HVDC based damping of inter-area power oscillations in hybrid AC-DC power systems." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/supervisory-control-scheme-for-facts-and-hvdc-based-damping-of-interarea-power-oscillations-in-hybrid-acdc-power-systems(cc03b44a-97f9-44ec-839f-5dcbcf2801f1).html.
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Modern interconnected power systems are becoming highly complex and sophisticated, while increasing energy penetrations through congested inter-tie lines causing the operating point approaching stability margins. This as a result, exposes the overall system to potential low frequency power oscillation phenomena following disturbances. This in turn can lead to cascading events and blackouts. Recent approaches to counteract this phenomenon are based on utilization of wide area monitoring systems (WAMS) and power electronics based devices, such as flexible AC transmission systems (FACTS) and HVDC links for advanced power oscillation damping provision. The rise of hybrid AC-DC power systems is therefore sought as a viable solution in overcoming this challenge and securing wide-area stability. If multiple FACTS devices and HVDC links are integrated in a scheme with no supervising control actions considered amongst them, the overall system response might not be optimal. Each device might attempt to individually damp power oscillations ignoring the control status of the rest. This introduces an increasing chance of destabilizing interactions taking place between them, leading to under-utilized performance, increased costs and system wide-area stability deterioration. This research investigates the development of a novel supervisory control scheme that optimally coordinates a parallel operation of multiple FACTS devices and an HVDC link distributed across a power system. The control system is based on Linear Quadratic Gaussian (LQG) modern optimal control theory. The proposed new control scheme provides coordinating control signals to WAMS based FACTS devices and HVDC link, to optimally and coherently counteract inter-area modes of low frequency power oscillations inherent in the system. The thesis makes a thorough review of the existing and well-established improved stability practises a power system benefits from through the implementation of a single FACTS device or HVDC link, and compares the case –and hence raises the issue–when all active components are integrated simultaneously and uncoordinatedly. System identification approaches are also in the core of this research, serving as means of reaching a linear state space model representative of the non-linear power system, which is a pre-requisite for LQG control design methodology.
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LIMA, Nelio Neves. "Operação do gerador de indução em conexão assíncrona com a rede monofásica." Universidade Federal de Goiás, 2010. http://repositorio.bc.ufg.br/tede/handle/tde/999.
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Previous issue date: 2010-03-26This text reports the effort to present a proposal of a power generation system based on cage rotor Induction Electrical Machine associated to a sinusoidally-switched PWM (Pulse Width Modulation) frequency converter responsible for maintaining constant 60 Hz frequency at the generator leads. DC side at the PWM converter is nonsynchronously connected to a single-phase utility line by means of a full-bridge current-fed thyristor inverter, employing a step-down DC-DC converter in order to turn the grid injected current into a sinusoidal waveform. The proposed system allows for the operation as cogenerator in sites fed by single-phase utility net where there is availability of energetic resources. The DC capacitor voltage (Vdc) is controlled through the DC side energy balance adjusting the amplitude of the active current sent to the utility grid. The control strategy employed was the analogic proportional-integral (PI) error compensation. The system is also able to act as reactive power compensator to the AC loads as the Cdc capacitor represents a voltage source to the inverter and the three-phase diode bridge allows for bidirectional power flow between AC and DC sides. Simulation and experimental results has corroborated system viability to provide three-phase balanced regulated voltages complying with ANEEL 505/2001 Resolution and with IEEE Std 519-1992.
Este trabalho apresenta a proposta de um sistema para geração de energia elétrica baseado na Máquina de Indução Trifásica (MIT) com rotor tipo gaiola de esquilo associada a um conversor de freqüência chaveado no modo PWM (modulação por largura de pulsos na sigla em inglês) senoidal. O lado CC do conversor de frequência é conectado assincronamente à rede monofásica da concessionária através de um inversor monofásico em ponte completa a tiristores, alimentado em corrente, e de um conversor CC-CC abaixador de tensão, utilizado para modular senoidalmente a corrente injetada na rede via inversor. Este sistema permite a operação como co-gerador em localidades alimentadas por linhas monofásicas e com disponibilidade de recursos energéticos. O conversor de freqüência é responsável por manter a freqüência fundamental nos terminais do gerador de indução fixa em 60 Hz. A tensão no capacitor Ccc (Vcc) é controlada através da manutenção do balanço energético no lado CC do conversor PWM, ajustando a amplitude da corrente ativa injetada na rede monofásica em um valor adequado. A estratégia empregada para implementação do controle foi a compensação analógica tipo proporcional-integral (PI) do erro de Vcc. O sistema é ainda capaz de atuar como compensador de potência reativa para as cargas CA, já que o capacitor Ccc representa uma fonte de tensão contínua para o inversor e a ponte trifásica a diodos permite o fluxo bidiredional de energia entre os lados CA e CC do sistema. Os resultados de simulação e experimentais sustentam a viabilidade do sistema para prover tensões trifásicas equilibradas e reguladas, satisfazendo os requisitos da resolução 505/2001 da ANEEL e da norma IEEE Std 519-1992 do IEEE/ANSI.
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Kreikebaum, Frank Karl. "Control of transmission system power flows." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50392.
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Power flow (PF) control can increase the utilization of the transmission system and connect lower cost generation with load. While PF controllers have demonstrated the ability to realize dynamic PF control for more than 25 years, PF control has been sparsely implemented.
This research re-examines PF control in light of the recent development of fractionally-rated PF controllers and the incremental power flow (IPF) control concept. IPF control is the transfer of an incremental quantity of power from a specified source bus to specified destination bus along a specified path without influencing power flows on circuits outside of the path.
The objectives of the research are to develop power system operation and planning methods compatible with IPF control, test the technical viability of IPF control, develop transmission planning frameworks leveraging PF and IPF control, develop power system operation and planning tools compatible with PF control, and quantify the impacts of PF and IPF control on multi-decade transmission planning.
The results suggest that planning and operation of the power system are feasible with PF controllers and may lead to cost savings. The proposed planning frameworks may incent transmission investment and be compatible with the existing transmission planning process. If the results of the planning tool demonstration scale to the national level, the annual savings in electricity expenditures would be $13 billion per year (2010$). The proposed incremental packetized energy concept may facilitate a reduction in the environmental impact of energy consumption and lead to additional cost savings.
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Depernet, Daniel. "OPTIMISATION DE LA COMMANDE D'UN ONDULEUR MLI A TROIS NIVEAUX DE TENSION POUR MACHINE ASYNCHRONE." Phd thesis, Université de Reims - Champagne Ardenne, 1995. http://tel.archives-ouvertes.fr/tel-00828554.
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Les progrès réalisés ces dernières années dans la commande des onduleurs MLI à deux niveaux de tension pilotant en vitesse variable des machines asynchrones de moyenne et grande puissance ont permis d'améliorer sensiblement les performances. L'utilisation récente des onduleurs MLI à trois niveaux de tension est très prometteuse en raison de la capacité de cette nouvelle structure d'onduleur à améliorer la qualité des courants dans la machine et à étendre sa commande à des domaines de puissance supérieurs à 2 MW. Nous définissons le principe de calcul et les limites de validité des principales techniques de modulation sinusoïdales à trois niveaux. Certaines d'entre elles se révèlent être tout à fait adaptées et performantes pour commander la machine dans les zones de faible vitesse. Nous proposons ensuite une méthode systématique de construction d'une commande optimisée. Les signaux sont calculés pour minimiser les harmoniques de courant et les pulsations de couple. Cette méthode est appliquée à un exemple concret, et la commande est implantée sur le microcontrôleur 80C196KC. La simulation des régimes établis permet d'affiner les études qualitatives des signaux. La bonne concordance entre les résultats expérimentaux et les résultats théoriques permet de confirmer la conservation des caractéristiques des signaux par la méthode de génération en temps réel. L'étude de l'association de la commande optimisée et d'une loi de contrôle vectoriel permet enfin de prouver la faisabilité d'un tel contrôle. Elle permet d'envisager l'amélioration des performances des entraînements de grande puissance en régimes permanent et transitoire simultanément.
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Laamiri, Saber. "Commande des systèmes électriques : machines synchrones et convertisseurs multi-niveaux." Thesis, Ecole centrale de Nantes, 2019. http://www.theses.fr/2019ECDN0031/document.
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Ce travail de thèse a pour objectifs l'observation et la commande des convertisseurs multi-niveaux et la commande des machines synchrones. Pour satisfaire le besoin des clients de l’entreprise GS Maintenance et pour des raisons de maintenance, une commande en courant de la machine synchrone est implémentée expérimentalement. L'accent est mis sur le démarrage de ce type de machines car durant ces phases de fonctionnement (basses vitesses), les forces électromotrices sont faibles pour assurer la commutation des thyristors de l'onduleur. Ensuite, l'entreprise a proposé à ses clients un convertisseur statique en moyenne tension afin de garder sa place dans la variation de vitesse. Dans ce cadre, une commande en tension moderne de la machine synchrone alimentée par un onduleur de tension est proposée et validée par des résultats de simulation. Compte tenu du fonctionnement en moyenne tension, les convertisseurs multi-niveaux ont été retenus par l’entreprise. Dans ce cadre, le convertisseur multicellulaire série est proposé dans ce travail et une commande directe basée sur la théorie des modes glissants et le principe de priorité est conçue pour assurer l'équilibrage des tensions flottantes du convertisseur. Cette commande a été généralisée pour un nombre quelconque de cellules du convertisseur et validée par des résultats de simulation pour un nombre de cellules égal à 7. Pour réduire le coût et l'encombrement du convertisseur, un observateur adaptatif des tensions flottantes est proposé en prenant en compte les états de commutation du convertisseur. Cet observateur est ensuite associé à la commande directe en boucle fermée. Un banc d'essai du convertisseur à 3 cellules est réalisé au sein de l’entreprise et l’ensemble « observateur + commande directe » est testé expérimentalement sur ce bancThis PhD thesis aims to the observation and control of multilevel converters and the synchronous machines control. To satisfy the needs of GS Maintenance's customers and for maintenance reasons, a control strategy for a current fed self controlled synchronous machine is validated by experiments tests. The proposed strategy focus on a very low speed because the machine counter electromotive force is insufficient for inverter thyristors switching. Recently, the company proposed for its customers a power converter with medium voltage to keep its place in the speed variation. So, a modern voltage control of the synchronous machine fed by a voltage inverter is proposed and validated by simulation results. Medium voltage operation encouraged the company to choose the multi-level converter. Then, the flying capacitor converter is proposed in this work and a direct control based on the sliding mode theory and the priority principle is designed to guarantee the voltage balance. This control strategy has been generalized for any number of cells of the converter and validated by simulation results for a 7 cells converter. To reduce the cost and complexity of the converter, an adaptive observer floating voltages is proposed by taking into account the switching states of the converter. This observer is then associated with the direct control in closed loop. A test bench of a 3 cells converter is set up in the company. Experimental tests of « observer based direct control » are then conducted on this test bench
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Bonnin, Xavier. "Alimentation électrique des dispositifs de décharge à barrière diélectrique." Phd thesis, Toulouse, INPT, 2014. http://oatao.univ-toulouse.fr/13645/1/bonnin.pdf.
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Les dispositifs DBD se répandent dans un grand nombre d’applications industrielles. Utilisés depuis plus de 150 ans pour la production d’ozone afin de décontaminer l’eau à grande échelle, ils ont depuis la fin du XXème siècle investi les domaines du traitement de surface polymère, du dépôt de couche mince sur substrat et de l’émission lumineuse pour la décontamination ainsi que la médecine. Ces dispositifs sont mis en oeuvre avec un générateur électrique dont les caractéristiques impactent fortement la qualité de la décharge. Ce travail s’inscrit en partie dans le cadre du développement d’une application de traitement de surface à pression atmosphérique. Il aborde la problématique de l’augmentation de la vitesse de dépôt de couche mince au travers des paramètres de l’alimentation électrique. Plus précisément, ce travail s’intéresse aux apports d’une alimentation en courant rectangulaire et aborde également les problématiques liées à la conception et à la fabrication de ce convertisseur. En particulier, une grande attention est portée sur l’étude du transformateur élévateur, car au travers de ses éléments parasites capacitifs, ce dernier peut limiter le transfert de puissance entre la source électrique et le dispositif DBD. Un deuxième aspect de cette étude consiste à entrevoir l’intérêt que revêtent deux convertisseurs statiques dédiés à l’alimentation de dispositifs DBD. Le premier consiste en une alimentation résonante en régime de conduction discontinue dont la particularité est de posséder trois degrés de liberté (fréquence, tension d’entrée et largeur d’impulsion), ce qui lui confère un intérêt exploratoire. Le second convertisseur consiste en une alimentation résonante haute tension et haute fréquence permettant l’éviction du transformateur élévateur, et mettant en oeuvre des interrupteurs au nitrure de gallium (GaN) afin d’atteindre une fréquence de fonctionnement supérieure au mega-Hertz avec un faible niveau de pertes.
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Reymond, Cédric. "Conception d'une structure innovante de convertisseur AC-DC de type Totem-pole avec correction du facteur de puissance : application aux chargeurs de batteries des véhicules électriques." Thesis, Tours, 2019. http://www.theses.fr/2019TOUR4015.
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Les gouvernements responsabilisent les états sur l’environnement avec la mise en œuvre de solution pour décarboner la production de l’électricité. En 2020, 20 % de l’énergie produite sera générée par les énergies renouvelables. Cependant ces énergies vertes sont intermittentes et nécessitent une capacité de stockage importante pour la gestion locale des « smart grids ». Cette solution pose deux nouvelles problématiques : la nécessité d’un convertisseur bidirectionnel et la gestion des courants d’appel. Pour faciliter l’étude de ces problématiques, la thèse propose de lier au travers d’un bilan de puissance, les performances des différents limiteurs de courant sur une topologie de convertisseur innovante. Cette analyse permet de mettre en exergue une solution alternative de limitation des courants d’appel dans la conversion de l’énergie. Enfin, un circuit novateur sur le contrôle des composants de puissance de type thyristors/Triacs sera proposé et caractérisé pour palier une des contraintes liées à la réversibilité du convertisseurGovernments empower states over the environment with implementation of solution to clean up the electricity production sources. In 2020, 20% of the produced energy will be generated by renewable energies. However, theses green energies are occasional and require a huge storage capacitance for the local smart grids management. This solution puts two new issues: the necessity of having a bidirectional converter and the inrush currents management. To facilitate the study of these problems, the thesis suggests binding through a power balance, the performances of the current limiter on an innovative topology converter. This analysis highlight an alternative solution of inrush current strategy in energy conversion. Finally, a novel control circuit for SCRs/Triacs components will be proposed and characterized for landing one of the constraints linked to the converter reversibility
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Lott, Christophe. "Filtrage actif parallèle des harmoniques de courant sur des réseaux industriels : étude théorique et réalisation d'une maquette à GTO." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL116N.
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Les convertisseurs statiques absorbent des courants non sinusoïdaux et consomment généralement de la puissance réactive. Ces deux phénomènes nouveaux sur le réseau ont engendré un certain nombre de perturbations allant du dysfonctionnement d'un équipement jusqu'à la destruction d'une partie des équipements connectés. Dans cette thèse, les problèmes liés aux perturbations générées par les convertisseurs statiques ont été étudiés et des solutions visant à les éliminer ont été présentées. Elles portent sur les méthodes de filtrage passif et actif. Quelques éléments de définition et de dimensionnement de filtres passif sont donnés. Le filtrage actif est ensuite traité. Les deux structures courant et tension sont étudiées et la structure tension a été retenue. Différents principes de contrôle du filtre actif à structure tension ont été présentés. La méthode d'identification des harmoniques par le principe de calcul des puissances active et réactive instantanées donne des résultats satisfaisants. Le contrôle par hystérésis et par MLI a été étudié. Différentes MLI sont présentées et leur influence sur le dimensionnement du filtre actif est étudiée. Des simulations numériques ont été réalisées. Une comparaison des résultats obtenus avec les méthodes de contrôle par hystérésis et MLI a été faite. Enfin, une maquette expérimentale de 100 KVA a été réalisée et testée sur un site industriel. Les essais de la maquette ont montré de bonnes performances du filtre actif à G. T. O. Le filtrage en tension d'un jeu de barres perturbé par un convertisseur de 5 MVA connecté sur un réseau amont a pu être également réalisé
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Гаврилюк, Ігор Миколайович, and Havryliuk Ihor. "Розробка проекту лінії електропередачі з вставкою постій¬ного струму." Master's thesis, ТНТУ імені Івана Пулюя, 2019. http://elartu.tntu.edu.ua/handle/lib/29562.
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В дипломній роботі виконано дослідження можливих варіантів об’єднання несинхронних електроенергетичних систем та систем з різними стандартами регулювання частоти.
Метою роботи є розробка лінії електропередачі «Ковель – Хелм» з вставкою постійного струму для продажу електроенергії з України у Польщу.
Об’єкти, аналогічні спроектованому у даному проекті, можна впровад¬жувати і в інших елек-тричних мережах, що дозволить значно зменшити розміри синхронних мереж змінного струму, запобігти або обмежити каскадні відключення, підвищити коефіцієнт корисної дії електромереж і надійність електроенергетичних систем.In the diploma paper deals with the possibility of combining non-synchronous power systems and systems with different frequency control standards. The purpose of the work is to develop a Kovel-Helm transmission line with a DC insert for the sale of electricity from Ukraine to Poland. Objects similar to those projected in this project can be implemented in other power grids, which will significantly reduce the size of AC synchronous networks, prevent or limit cascade outages, increase the efficiency of grids and the reliability of power systems.
ПЕРЕЛІК УМОВНИХ СКОРОЧЕНЬ.................................................................... 7 ВСТУП .................................................................................................................…8 1 АНАЛІТИЧНА ЧАСТИНА ...............................................................................13 1.1 Призначення вставок постійного струму......................................................13 1.2 ВВППС – основні характеристики системи .................................................15 1.3 Варіанти застосування ВВППС .....................................................................16 1.4 Керування потужністю ...................................................................................17 1.5 Поведінка ВВППС в умовах виходу з ладу системи змінного струму......18 1.6 Вплив підключеної мережі змінного струму на ВПС .................................19 1.7 Споживання реактивної потужності .............................................................21 1.8 Висновки до розділу .......................................................................................23 2 НАУКОВО-ДОСЛІДНА ЧАСТИНА................................................................24 2.1 Пріоритетні напрями діяльності магістрального електромережевого комплексу.........................................................................................................24 2.2 Заходи шодо зниження комерційних втрат електроенергії ........................28 2.3 Перспективи передачі електроенергії за допомогою постійного струму .30 2.4 Основні причини використання ППС в ОЕС України ................................32 2.5 Висновки до розділу .......................................................................................35 3 ТЕХНОЛОГІЧНА ЧАСТИНА ..........................................................................36 3.1 Вибір напруги ліній електропередач постійного струму............................36 3.2 Вибір схеми вставки постійного струму.......................................................40 3.3 Перетворення й регулювання струму конверторами ..................................41 3.4 Вибір тиристорів .............................................................................................44 3.5 Система захисту тиристорів від перенапруг та перевантажень .................48 3.6 Система охолодження тиристорних модулів ...............................................50 3.7 Визначення кількості тиристорів у вентильних групах перетворювача ...52 3.8 Висновки до розділу .......................................................................................54 4 ПРОЕКТНО-КОНСТРУКТОРСЬКА ЧАСТИНА ...........................................55 4.1 Вибір раціонального січення проводів .........................................................55 6 4.2 Розрахунок споживання реактивної енергії перетворювачами..................56 4.3 Усунення впливу вищих гармонік напруги й струму у схемі ВПС...........60 4.4 Розрахунок фільтрокомпенсуючого пристрою............................................65 4.5 Активні фільтри...............................................................................................71 4.6 Висновки до розділу .......................................................................................74 5 СПЕЦІАЛЬНА ЧАСТИНА................................................................................75 5.1 Вибір трансформатора ....................................................................................75 5.2 Компенсація реактивної потужності.............................................................78 5.3 Вибір місця під’єднання компенсаційних пристроїв ..................................81 5.4 Розрахунок потужності компенсаційних пристроїв ....................................81 5.5 Зменшення струму несиметрії у вставках постійного струму ...................84 5.6 Струм к.з. на шинах високої напруги трансформаторів .............................86 5.7 Вибір обладнання ............................................................................................87 5.8 Висновки до розділу .......................................................................................92 6 ОБГРУНТУВАННЯ ЕКОНОМІЧНОЇ ЕФЕКТИВНОСТІ..............................93 6.1 Критерії економічної ефективності енергетичного виробництва..............93 6.2 Визначення капітальних затрат .....................................................................94 6.3 Вартість електроенергії ..................................................................................95 6.4 Розрахунок економічної ефективності..........................................................98 7 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ ...100 7.1 Заходи безпеки при обслуговуванні електроустановок ............................100 7.2 Захист персоналу від впливу електричних і електромагнітних полів .....103 7.3 Захист персоналу підстанції від наведених напруг ...................................106 8 ЕКОЛОГІЯ........................................................................................................108 8.1 Актуальність охорони навколишнього середовища..................................108 8.2 Вплив на людину електромагнітного забруднення довкілля ...................108 8.3 Вплив магнітного поля повітряних ліній постійного струму високої і надвисокої напруги на навколишнє середовище.......................................110 ЗАГАЛЬНІ ВИСНОВКИ ДО ДИПЛОМНОЇ РОБОТИ ...................................112 ПЕРЕЛІК ПОСИЛАНЬ .......................................................................................113
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Anele, Amos Onyedikachi. "Nonlinear modelling and control of a thyristor-controlled series capacitor for power flow enhancement." 2012. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000968.
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M. Tech. Electrical Engineering.Discusses energy as the basic necessity for the economic development of a country. Many functions necessary to present-day living grind to halt when the supply of energy stops. Energy exists in different forms in nature but the most important form is the electrical energy. Therefore, enhancing power flow in transmission systems is important for efficient power supply because a modern-day society requires a large amount of electrical energy for domestic, commercial and industrial purposes. Among the various means of enhancing power flow in transmission systems with the help of FACTS devices, this research work focussed on the aspect of improving the power system stability. Therefore, efficient supply of electric power to various customer load demands can be achieved when the future power system engineers and researchers carry out nonlinear modelling, bifurcation analysis and control of their system with FACTS devices such as TCSC for power system stability enhancement.
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Mazibuko, Ronnie H. "Design and implementation of a thyristor controlled series capacitor for research laboratory application." Thesis, 2003. http://hdl.handle.net/10413/4157.
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The power transfer capability of a transmission line is determined by the magnitude of the voltage at each end of the line, angle difference of these voltages and the impedance of the line. This impedance is mainly inductive. Traditionally, fixed series capacitor banks have been used for series compensation. However, due to instability problems associated with loading transmission line close to their thermal limits, researchers have looked at other alternatives to line compensation by static devices such as fixed series capacitors. Flexible AC Transmission Systems (FACTS) has allowed power utilities to use existing transmission line networks close to their thermal limits without compromising stability of the power system. A FACTS series compensator is capable of influencing the transmission of power in a transmission line by dynamic control of the series compensating reactance inserted in the line. There are several different devices under the FACTS family, however, in this thesis only the Thyristor-Controlled Series Capacitor (TCSC) was considered. A TCSC comprises a fixed capacitor in parallel with a thyristor-controlled reactor (TCR). By varying the firing angle ex:. of the thyristors, the TCSC can be made to act in variable inductive or capacitive reactance mode. The thesis' overall objective was to design a practical TCSC for use in a research laboratory for further research initiatives. This thesis looks at different issues that need to be considered when designing and rating a TCSC compensator. In particular, the thesis examines the effects of different sizes of TCSC components on the rating of the device, the effects of harmonics on the TCSC ratings, sizing of TCSC's variable reactance, and the response time of TCSC to a step change in the firing angle. A mathematical model of a TCSC in a single-machine infinite bus (SMIB) system was developed and subsequently used in the initial design of the TCSC. Studies that were done using mathematical model of the TCSC module confirmed the ability of the TCSC controller to dynamically control the capacitive compensating reactance in the transmission line. The thesis then describes the development of a laboratory-scale TCSC for research investigations. Measured results from the laboratory demonstrate the ability of the TCSC series compensator to provide rapid control of series reactance of a transmission line. A detailed mathematical model of the SMIB equipped with TCSC module was developed, using parameter values of the laboratory scale prototype, to investigate power oscillation damping. Time-domain simulation results are presented in this thesis to demonstrate its ability to damp power swings in an electrical network.Thesis (M.Sc.Eng.)-University of Natal, Durban, 2003.
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Pandit, Nakul. "Simulation and control of thyristor controlled series capacitors." 2007. http://proquest.umi.com/pqdweb?did=1240710321&sid=10&Fmt=2&clientId=39334&RQT=309&VName=PQD.
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Thesis (M.S.)--State University of New York at Buffalo, 2007.Title from PDF title page (viewed on July 06, 2007) Available through UMI ProQuest Digital Dissertations. Thesis adviser: Safiuddin, Mohammed. Includes bibliographical references.
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Deacon, Johan Abraham. "Drywingselektroniese mutators met siklies-resonante gapsers en hekafskakelbare tiristors." Thesis, 2014. http://hdl.handle.net/10210/12202.
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M.Ing. (Electrical & Electronic Engineering)The gate turn-off thyristor is discussed as a power switch. A gate-firing circuit for gate turn-off thyristors in the range 10 A - 300 A was developed. The resonant dc-link as snubber for voltage fed inverters is discussed. On considering various factors, the gate turn-off thyristor was chosen as switching component in the inverter. The problems that deve16ped with the use of gate turn-off thyristors in resonant dc-link inverters w,re discussed. Which lead to the development of a storage time compensator for gate turn-off thyristors. Attention was given to the various possible control methods for the resonant dc-link. A study of the possible control strategies results in the development and manufacturing of both a single-phase and a three-phase controller. The operation of the resonant inverter and inverter/load system were evaluated in terms of wave shapes in the time domain.
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Vermooten, Dan. "Die ontwikkeling en eienskappe van 'n tiristorbeheerde reaktiewe driefase netwerk." Thesis, 2014. http://hdl.handle.net/10210/10102.
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M.Ing.This dissertation describes the development and characteristics of a thyristor controlled reactive three phase network which is used for the compensation of reactive power in a power network. The problem of distortion in power networks is illustrated and the development of a thyristor controlled reactive three phase network is motivated. The considerations that were taken into account in the design of the network are explained and the experimental setup is evaluated. A computer simulation was done to verify a single phase model of the reactive power network. The driving function in power networks is a singular harmonic voltage and distortion is defined as any deviation ofthe current from a scaled, in phase version of the voltage. Distortion is caused byloads with a non-linear nature such as arc furnaces and variable speed drives. Reactive power, which forms part of the distortion problem, is caused by loads with a phase shift between the voltage and current. Distortion has several adverse effects on a power network resulting in the degrading of the quality of the supply. At present the state of the art in technology does not permit the economic compensation of distortion with dynamic filters at MVA levels. However, by compensating the reactive power present in a network byusing variable reactive elements, the remaining distortion in the network can be compensated by using a dynamic filter. The combination ofa thyristor controlled reactive network and a dynamic filter are termed a hybrid power compensator. Results are shown where a hybrid power compensator has been implimented to compensate distortion caused by a non-linear load. The thyristor controlled reactive three phase network described in this dissertation is rated at 21 kVAr and comprises the following on a per phase basis: The series combination of a fixed capacitor bank and a filter inductance is connected via an isolation transformer to a reactor and two anti parallel thyristors. The reactive elements have been dimensioned in such a way that reactive power can only be generated and not absorbed.
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Pillay, Anand. "A DSP-based digital controller for a thyristor controlled series capacitor." Thesis, 2007. http://hdl.handle.net/10413/2245.
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The power transfer capability of long high voltage transmission lines is often limited by the inductive reactance of the transmission line. Series compensation is in some instances employed to lower the inductive reactance of the transmission line which increases the transmission line power transfer capability. Numerous methods have been employed to provide series compensation of a transmission line. One such method is to use a thyristor controlled series capacitor (TCSC). A thyristor controlled senes capacitor (TCSC) belongs to the flexible altemating CUlTent transmission systems (FACTS) family of devices. It is a variable capacitive and inductive reactance device that can be used to provide series compensation in high voltage transmission lines. One of the significant advantages that a TCSC has over other series compensation devices is that the TCSC's reactance is instantaneously and continuously variable. This means that the TCSC can be used not only to provide series compensation but can also be used to enhance the stability of the power system. However accurate control of the TCSC is challenging due to its highly non-linear variable reactance characteristic. The TCSC consists of back to back thyristors that control the reactance of the TCSC. By changing the trigger angle of these back to back thyristors it is possible to vary the reactance of the TCSC. The reactance characteristic becomes highly non linear at higher levels of compensation; at such operating points the trigger angle of the thyristors needs to be accurately controlled to avoid small variations in the thyristor trigger angle causing significant variation in the reactance of the TCSC. Literature has shown that there is an acceptable limit to the resolution of the thyristor trigger angle based on the parameters of the components used in the TCSC. If a controller is developed to meet this acceptable level of thyristor trigger angle resolution, then the operation of the TCSC will also be acceptable and its operation will not result in unwanted fluctuations in the transmission line variables. This thesis details the development of such a controller for use in a laboratory-scale TCSC. The thesis then goes on to present the practical results obtained from laboratory experiments on the laboratory-scale TCSC with the TCSC triggering controller being used to control the operation of the laboratory-scale TCSC. For purposes of comparison and benchmarking, a detailed simulation model of the laboratory-scale TCSC is developed to take into account the non-ideal properties of the components used in make-up of the laboratory-scale TCSC since the theoretical model is derived assuming ideal conditions. The detailed simulation model is also used to aid in the redesign the power circuit of the laboratory-scale TCSC in an attempt to improve the perfonnance of the laboratory-scale TCSC by obtaining better agreement between the theoretical and practical results. The redesigned laboratory-scale TCSC is used to obtain practical results to COnfill11 the findings of the simulation studies. Finally, the TCSC triggering controller is tested using a real time digital simulator (RTDS). The simulation model developed on the RTDS consisted of a two area, four generator power, with the TCSC connected between the two areas. The RTDS simulation model is used to study the ability of the TCSC to damp inter-area mode oscillations and hence the RTDS simulation model incorporated a power oscillation controller. The input of TCSC triggering controller was "connected" to the power oscillation damping controller and the output of the TCSC triggering controller was "connected" to the thyristors of the TCSC.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2007.
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Subhash, Sujatha. "Investigations On The Application Of Thyristor Controlled Series Compensators In Power Systems." Thesis, 1999. http://etd.iisc.ernet.in/handle/2005/1636.
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Kabiri, Khosro. "Analysis and control of subsynchronous resonance in the presence of thyristor controlled series compensation." Thesis, 2004. http://hdl.handle.net/2429/16053.
Full textAbstract:
In this thesis, the problem of subsynchronous mechanical oscillations in the shaft assembly of
a turbo-generator with its steam turbine stages is studied, when the generator is connected
to a Thyristor Controlled Series Capacitor (TCSC) compensated transmission line.
The first three-phase thyristor controlled series capacitor was installed in 1992. The
usefulness of this device for mitigating subsynchronous resonance has been established. There
are, however, issues remaining to be investigated. A point of contention is the nature of the
behaviour of TCSC towards subsynchronous frequencies. Although TCSC does not have
resistive components as such, it puts up significant resistance to the subsynchronous current
flow when in open-loop operation. This characteristic, known as passive damping, has been
observed both on network analyzers and in simulations. Here, with the aid of analytical
relations and discrete Fourier analysis, a physical explanation is provided for this behaviour.
The average steady-state linearization, although an efficient method for obtaining linear
models for switching circuits, fails to capture the passive damping of TCSC. The Poincaré
mapping technique, on the other hand, provides the state matrix of the discrete linear time-invariant
system that is equivalent to the linearized time-periodic model of the switching
circuit in the sense of Lyapunov. Therefore it is accurate in the eigenvalue analysis for
stability studies.
Poincaré mapping together with a perturbation method is used here to find a linearized
discrete model for a TCSC compensated system, in which the small signal variation of the
state is explicitly given in terms of the small signal variation of the TCSC firing angles. The
model is used first for the eigenvalue analysis and then for the design of an all-stabilizing
closed-loop controller for small signal control of the thyristor firing angles in order to damp
subsynchronous mechanical oscillations. In the past, Poincaré mapping has been used to derive continuous dynamic models for the
TCSC alone, by first finding the discrete advance map, and then by converting the equations
to the continuous domain.
Here, we discretize the generator, line and TCSC equations together to arrive at a state
space model for the entire system. The First IEEE Subsynchronous Resonance Benchmark
Model is our case study. The method is general enough, however, to be used for other
configurations as well.
Finally, the steady-state relations of TCSC in non-equidistant firing are developed, and
its dynamic behaviour with the new open-loop firing scheme is studied using transient simulation.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Mazur, Garry Brian. "Control of power system harmonics with firing angle modulation of a thyristor controlled reactor." 1986. http://hdl.handle.net/1993/15414.
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Li, Hsing-Chieh, and 李興傑. "A Study of Thyristor-Controlled Series Capacitor (TCSC)on Control Performance of Induction Machines." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/x7up62.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
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Abstract This thesis investigates the application of variable-impedance characteristics of thyristor-controlled series capacitor (TCSC) of flexible AC transmission systems (FACTS) on control performance of three-phase induction machines. Both qd0-axis and three-phase abc frame induction-machine models are respectively employed to study steady-state and dynamic characteristics of the studied machine under different operating conditions. Regarding to speed control performance of an induction motor and active-power control of a grid-connected induction generator (GCIG), the steady-state performance of TCSC under different values of transmission line impedance, the dynamic control characteristics of TCSC, and the performance of a designed speed controller are investigated.
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Murray, Nick. "Flexible power control in large power current source conversion : a thesis presented for the degree of Doctor of Philosophy in Electrical and Computer Engineering at the University of Canterbury, Christchurch, New Zealand /." 2008. http://hdl.handle.net/10092/2610.
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Gumunyu, Tonderayi. "Use of Thyristor Controlled Series Capacitors (TCSCs) to enhance power system transient stability and their possible application on the South African Grid." Thesis, 2015. http://hdl.handle.net/10539/22693.
Full textAbstract:
This research report is submitted as a partial fulfilment of the requirements for a
Master of Science degree in Electrical Engineering (Power).Thyristor Controlled Series Capacitors (TCSCs) are FACTS devices which incorporate power-electronic-based and other static controllers to enhance controllability and increase power transfer capability. This research investigated the possibility of applying TCSCs on the South African transmission network, in particular application on long transmission lines connecting bulk thermal generators in the northern part of South Africa to load centres located hundreds of kilometres elsewhere in the country. The investigation, conducted using PSS/E (a power system analysis software) demonstrated that application of TCSCs on this part of South African transmission network results in improved transient stability margins. The resulting improvement in transient stability is comparable to other transient stability enhancement options like addition of transmission lines, thus the use of TCSCs can be considered as an alternative. Further studies would be vital to understand the interaction between Power System Stabilizers (PSSs) and TCSCs in order to ensure proper tuning and interaction amongst the devices.
MT2017
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Кбайдат, Імад. "Дослідження та розробка системи керування електричним приводом." Магістерська робота, 2020. https://dspace.znu.edu.ua/jspui/handle/12345/4863.
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Кбайдат Імад. Дослідження та розробка системи керування електричним приводом : кваліфікаційна робота магістра спеціальності 153 "Мікро- та наносистемна техніка" / наук. керівник З. А. Ніконова. Запоріжжя : ЗНУ, 2020. 105 с.UA : Розроблено привід подачі робочого інструмента металообро-бних верстатів, який має повністю цифрове рішення системи авто-матичного регулювання і системи імпульсно-фазового керування, що дозволило збільшити функціональність.
EN : The drive of giving of the working tool of metalworking machines which has completely digital decision of system of automatic control and system of pulse-phase control that allowed to increase functionality is developed.
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Banerjee, Debmalya. "Load Commutated SCR Current Source Inverter Fed Induction Motor Drive With Sinusoidal Motor Voltage And Current." Thesis, 2008. http://hdl.handle.net/2005/744.
Full textAbstract:
This thesis deals with modeling, simulation and implementation of Load Commutated SCR based current source Inverter (LCI) fed squirrel cage induction motor drive with sinusoidal voltage and sinusoidal current. In the proposed system, the induction motor is fed by an LCI. A three level diode clamped voltage source inverter (VSI) is connected at the motor terminal with ac chokes connected in series with it. The VSI currents are controlled in such a manner that it injects the reactive current demanded by the induction motor and the LCI for successful commutation of the SCRs in the LCI. Additionally, it absorbs the harmonic frequency currents to ensure that the induction motor draws sinusoidal current. As a result, the nature of the motor terminal voltage is also sinusoidal.
The concept of load commutation of the SCRs in the LCI feeding an induction motor load is explained with necessary waveforms and phasor diagrams. The necessity of reactive compensation by the active filter connected at the motor terminal for the load commutation of the thyristors, is elaborated with the help of analytical equations and phasor diagrams. The requirement of harmonic compensation by the same active filter to achieve sinusoidal motor current and motor voltage, is also described. Finally, to achieve the aforementioned induction motor drive, the VA ratings of the active filter (VSI) and the CSI with respect to VA rating of the motor, are determined theoretically. The proposed drive scheme is simulated under idealized condition. Simulation results show good steady state and dynamic response of the drive system. Load commutation of the SCRs in the LCI and the sinusoidal profile of motor current and voltage, have been demonstrated.
As in LCI fed synchronous motor drives, a special mode of operation is required to run up the induction motor from standstill. As the SCRs of the LCI are load commutated, they need motor terminal voltages for commutation. At standstill these voltages are zero. So, a starting strategy has been proposed and adopted to start the motor with the aid of the current controlled VSI to accelerate until the motor terminal voltages are high enough for the commutation of the SCRs in the LCI.
The proposed drive is implemented on an experimental setup in the laboratory. The IGBT based three level diode clamped VSI has been fabricated following the design of the standard module in the laboratory. A generalized digital control platform is also developed using a TMS320F2407A DSP. Two, three phase thyristor bridges with necessary firing pulse circuits have been used as the phase controlled rectifier and the LCI respectively. Appropriate protection scheme for such a drive is developed and adopted to operate the drive. Relevant experimental results are presented. They are observed to be in good agreement with the simulation results.
The effect of capacitors connected at the output of the LCI in the commutation process of the SCRs in the LCI is studied and analyzed. From the analysis, it is understood that the capacitors form a parallel resonating pair with filter inductor and the motor leakage inductance, which results in an undesired oscillation in the terminal voltage during each of the commutation intervals leading to commutation failure. So, in the final system, the capacitors are removed to eliminate any chance of commutation failure of the SCRs in the LCI. It is shown by experiment that the commutation of the SCRs takes place reliably in the absence of the capacitors also. The commutation process is studied and analyzed without the capacitors to understand the motor terminal voltage waveform of the experimental results.