Thèses sur le sujet « AC/DC Security; Stability »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 34 meilleures thèses pour votre recherche sur le sujet « AC/DC Security; Stability ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
Bakhos, Gianni. « Gestion de la sécurité du réseau électrique AC & ; DC : évaluation et amélioration ». Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALT014.
Texte intégralToday, the integration of renewable energies poses problems of congestion and uncertainty on the electricity network, given the intermittency and unpredictability of this type of energy. What's more, for reasons of profitability and efficiency, the power generated from renewables is transmitted in the form of High Voltage Direct Current (HVDC). A new concept has therefore emerged, that of merging HVDC interconnections into an existing meshed network, which will bring greater flexibility to the operation of the overall system. The result is a hybrid electricity transmission system with significant mutual interactions between the existing AC system and the integrated DC system. While the stability problems of the AC network have now been identified, those of the hybrid system still need to be studied, since the integration of rapidly controllable power converters could modify the behaviour of the entire system. As a result, this thesis project seeks to establish an innovative study encompassing the entire AC/DC hybrid system. This will focus on a security assessment that takes into account operational constraints and the ability of the system to reach a new equilibrium. In addition, this thesis will address the stabilisation challenges of the overall hybrid system. To this end, the assignments will consist of a preliminary study of the state of the art: what is the physical nature of the instability problems of the AC system? What types and ranges of disturbances should be considered for stability assessment? Finally, what modelling and control of the HVDC system? All of this will enable the development of an inclusive security assessment tool that takes into account different system control methods. An analysis will also be carried out to understand the influence of the parameters and control methods adopted. This will help us to implement a systematic means of control to improve network security and optimise power distribution across a Multi-Terminal DC network
Salehi, Pour Mehr Vahid. « Development and Verification of Control and Protection Strategies in Hybrid AC/DC Power Systems for Smart Grid Applications ». FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/804.
Texte intégralEriksson, Robert. « Security-centered Coordinated Control in AC/DC Transmission Systems ». Licentiate thesis, Stockholm : Royal Institute of Technology, 2008. http://kth.diva-portal.org/smash/record.jsf?searchId=4&pid=diva2:101.
Texte intégralGonzalez-Torres, Juan Carlos. « Transient stability of high voltage AC-DC electric transmission systems ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS041.
Texte intégralThe new policy frameworks adopted by national authorities has encouraged the large scale-integration of Renewable Energy Systems (RES) into bulk power systems. The large-scale integration of RES will have consequences on the electricity transmission system as it is conceived today, since the transmission of bulk power over long distances could lead the existing transmission systems to work close to their limits, thus decreasing their dynamic security margins. Therefore more complex transmissions systems are needed.Under this scenario, HVDC transmission systems raise as the most attractive solution for the reinforcement and improvement of existing AC networks, not only using point-to-point configurations, but also in a Multi-Terminal configuration. The introduction of HVDC transmission systems will eventually result in a hybrid high voltage AC/DC power system, which requires to be analyzed as a unique system in order to understand the interactions between the AC network and the DC grid.This thesis addresses the transient stability analysis of hybrid AC/DC electric transmission systems. More in particular, two questions sought to be investigated: What is the impact of a DC contingency on AC transient stability? How can we take advantage of the of DC transmission systems as control inputs in order to enhance AC transient stability?In the first part of this work, the mathematical models of the hybrid AC/DC grid are described as well as the necessary tools for the analysis of the system taking into account its nonlinear nature. Then, a thorough analysis of transient stability of the power system in the particular case of a DC fault and the execution of the corresponding protection strategies is done. As a complement, stability indicators and tools for sizing future MTDC grids in order to respect the constraints of existing protection strategies are proposed.The second part of the thesis addresses the control proposals for the modulation of power references of the HVDC transmission systems with the purpose of transient stability enhancement of the surrounding AC system. Firstly, we focus our study in the nonlinear control of point-to-point HVDC links in hybrid corridors. Fast power compensation, injection of damping power and injection of synchronizing power are identified as the mechanisms through which HVDC systems can improve stability margins.Finally, a control strategy for transient stability enhancement via active power injections of an MTDC grid is proposed. Using communication between the stations, the proposed decentralized control injects damping and synchronizing power between each pair of converters using only measurements at the converters level. The proposed implementation allows to fully use the available headroom of the converters by dealing with power limits in a decentralized way
Obradovic, Danilo. « Coordinated Frequency Control Between Interconnected AC/DC Systems ». Licentiate thesis, KTH, Elkraftteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280156.
Texte intégralQC 20200907
multiDC - Advanced Control and Optimization Methods for AC and HVDC Grids
Wang, Hualei. « The protection of transmission networks containing AC and DC circuits ». Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.655718.
Texte intégralMartínez, Sanz Inmaculada. « Control of AC/DC systems for improved transient stability and frequency support provision ». Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/25956.
Texte intégralFernandopulle, Nilkamal Alden Robert T. H. Findlay Raymond D. Tang Chi-keung. « Improved dynamic security assessment for AC/DC power systems using transient energy functions ». *McMaster only, 2005.
Trouver le texte intégralSarker, Partha Sarathi. « DYNAMIC MODELING, STABILITY ANALYSIS AND CONTROL OF AC/DC INTERCONNECTED MICROGRID USING DQ-TRANSFORMATION ». Master's thesis, Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/518146.
Texte intégralM.S.E.E.
In recent years, there have been significant changes in power systems due to the integration of renewables, distributed generation, switched power loads, and energy storage systems, etc. Locally these AC/DC microgrids include both DC generation (such as solar PV) and AC generation (such as wind generation), various DC and AC loads, converters and inverters, and energy storage systems, such as storage batteries and supercapacitors. DC systems are often characterized as low inertia systems whereas AC generation and systems are usually high inertia and high time constant systems. As such, various components of the microgrid will have different temporal characteristics in case of disturbances, such as short circuit, load switchings, etc. which may lead to instability of the microgrid. This research develops the first principle model for coupling the AC and the DC subsystem of an integrated AC/DC microgrid utilizing the dq-framework. The developed model is highly nonlinear and captures the dynamic interaction between the AC and DC subsystems of the microgrid. Lyapunov stability is used to evaluate the stability of the complete system. Simulation results show that the AC and DC subsystems are tightly dynamically coupled so that any disturbance in one subsystem induces transients in the other subsystem. Induced transients due to pulse loads on the AC and DC subsystems clearly show that generator damper winding alone may not be enough to mitigate transients in the microgrid. Addition of prime mover and excitation system controllers for the generator improves the transients primarily on the AC subsystem. Thus, a battery storage with a charge/discharge controller was also added to the DC subsystem. Simulations of the AC/DC microgrid with all three controllers validate the smooth operation of the system for all types of disturbances. The proposed method can be extended in modeling microgrid with multiple generators and various types of loads.
Temple University--Theses
Yu, Chang. « An investigation of subsynchronous oscillation of AC/DC power systems modeling and analysis / ». Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B37151885.
Texte intégralYu, Chang, et 余暢. « An investigation of subsynchronous oscillation of AC/DC power systems : modeling and analysis ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B37151885.
Texte intégralAdediran, Adeoti Taiwo. « A study of power electronic building block (PEBB)-based integrated shipboard power systems during reconfiguration ». Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/413.
Texte intégralMusa, Aysar [Verfasser], Antonello [Akademischer Betreuer] Monti et Albert [Akademischer Betreuer] Moser. « Advanced control strategies for stability enhancement of future hybrid AC/DC networks / Aysar A. Aydan Musa ; Antonello Monti, Albert Moser ». Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1210929228/34.
Texte intégralAwan, Ahmed-Bilal. « Contribution à l’étude de la stabilité des systèmes électriques distributés autour d’un bus commun d'alimentation ». Thesis, Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL099N/document.
Texte intégralStability is the first and very important factor in all modes of operation for a Distributed Power System (DPS). In DPS, loads are connected to the DC-bus through an input LC filter. Most of the loads in DPS of aircraft present a constant power load characteristic within a domain of operation in which they are tightly controlled. So they can be modeled as negative resistance. Change of the load in one subsystem may lead a stable system into instability. A practical solution to decrease the risk of instability presented in this thesis which consists in modifying the control of the converters or inverter-motor drive system connected to the DC-bus. This solution permits to stabilize the system even with a smaller size of capacitor. In the first part of the thesis, a linear method is presented which allows investigating local stability of an inverter-motor-drive system connected to the grid through an LC filter and a rectifier. An oscillation compensation technique is used to improve the stability margin of the system and the size of the dc-link capacitance without modifying structure of the torque or current loops. This technique consists in superposing a stabilizing power on the absorbed power by the drive. Although linear models can be successfully employed to locally describe the behavior of a physical system, they often fail to provide a satisfactory large signal characterization. In the second part, two methods for the large signal stabilization of the electrical system are presented. In the last part, a new method, based on dynamic specifications, is proposed to study the stability of a cascaded electric system
Perez, Filipe. « Control of AC/DC Microgrids with Renewables in the Context of Smart Grids : Including Ancillary Services and Electric Mobility ». Electronic Thesis or Diss., université Paris-Saclay, 2020. http://www.theses.fr/2020UPASG011.
Texte intégralMicrogrids are a very good solution for current problems raised by the constant growth of load demand and high penetration of renewable energy sources, that results in grid modernization through “Smart-Grids” concept. The impact of distributed energy sources based on power electronics is an important concern for power systems, where natural frequency regulation for the system is hindered because of inertia reduction. In this context, Direct Current (DC) grids are considered a relevant solution, since the DC nature of power electronic devices bring technological and economical advantages compared to Alternative Current (AC). The thesis proposes the design and control of a hybrid AC/DC Microgrid to integrate different renewable sources, including solar power and braking energy recovery from trains, to energy storage systems as batteries and supercapacitors and to loads like electric vehicles or another grids (either AC or DC), for reliable operation and stability. The stabilization of the Microgrid buses’ voltages and the provision of ancillary services is assured by the proposed control strategy, where a rigorous stability study is made. A low-level distributed nonlinear controller, based on “System-of-Systems” approach is developed for proper operation of the whole Microgrid. A supercapacitor is applied to deal with transients, balancing the DC bus of the Microgrid and absorbing the energy injected by intermittent and possibly strong energy sources as energy recovery from the braking of trains and subways, while the battery realizes the power flow in long term. Dynamical feedback control based on singular perturbation analysis is developed for supercapacitor and train. A Lyapunov function is built considering the interconnected devices of the Microgrid to ensure the stability of the whole system. Simulations highlight the performance of the proposed control with parametric robustness tests and a comparison with traditional linear controller. The Virtual Synchronous Machine (VSM) approach is implemented in the Microgrid for power sharing and frequency stability improvement. An adaptive virtual inertia is proposed, then the inertia constant becomes a system’s state variable that can be designed to improve frequency stability and inertial support, where stability analysis is carried out. Therefore, the VSM is the link between DC and AC side of the Microgrid, regarding the available power in DC grid, applied for ancillary services in the AC Microgrid. Simulation results show the effectiveness of the proposed adaptive inertia, where a comparison with droop and standard control techniques is conducted
Aban, Vahap Volkan. « The Design, Control, And Performance Analysis Of Ac Motor Drives With Front End Diode Rectifier Utilizing Low Capacitance Dc Bus Capacitor And Comparison With Conventional Drives ». Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615099/index.pdf.
Texte intégralAwan, Ahmed-Bilal. « Contribution à l’étude de la stabilité des systèmes électriques distributés autour d’un bus commun d'alimentation ». Electronic Thesis or Diss., Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL099N.
Texte intégralStability is the first and very important factor in all modes of operation for a Distributed Power System (DPS). In DPS, loads are connected to the DC-bus through an input LC filter. Most of the loads in DPS of aircraft present a constant power load characteristic within a domain of operation in which they are tightly controlled. So they can be modeled as negative resistance. Change of the load in one subsystem may lead a stable system into instability. A practical solution to decrease the risk of instability presented in this thesis which consists in modifying the control of the converters or inverter-motor drive system connected to the DC-bus. This solution permits to stabilize the system even with a smaller size of capacitor. In the first part of the thesis, a linear method is presented which allows investigating local stability of an inverter-motor-drive system connected to the grid through an LC filter and a rectifier. An oscillation compensation technique is used to improve the stability margin of the system and the size of the dc-link capacitance without modifying structure of the torque or current loops. This technique consists in superposing a stabilizing power on the absorbed power by the drive. Although linear models can be successfully employed to locally describe the behavior of a physical system, they often fail to provide a satisfactory large signal characterization. In the second part, two methods for the large signal stabilization of the electrical system are presented. In the last part, a new method, based on dynamic specifications, is proposed to study the stability of a cascaded electric system
Qoria, Taoufik. « Nouvelles lois de contrôle pour former des réseaux de transport avec 100% d’électronique de puissance ». Thesis, Paris, HESAM, 2020. http://www.theses.fr/2020HESAE041.
Texte intégralThe rapid development of intermittent renewable generation and HVDC links yields an important increase of the penetration rate of power electronic converters in the transmission systems. Today, power converters have the main function of injecting power into the main grid, while relying on synchronous machines that guaranty all system needs. This operation mode of power converters is called "Grid-following". Grid-following converters have several limitations: their inability to operate in a standalone mode, their stability issues under weak-grids and faulty conditions and their negative side effect on the system inertia.To meet these challenges, the grid-forming control is a good solution to respond to the system needs and allow a stable and safe operation of power system with high penetration rate of power electronic converters, up to a 100%. Firstly, three grid-forming control strategies are proposed to guarantee four main features: voltage control, power control, inertia emulation and frequency support. The system dynamics and robustness based on each control have been analyzed and discussed. Then, depending on the converter topology, the connection with the AC grid may require additional filters and control loops. In this thesis, two converter topologies have been considered (2-Level VSC and VSC-MMC) and the implementation associated with each one has been discussed. Finally, the questions of the grid-forming converters protection against overcurrent and their post-fault synchronization have been investigated, and then a hybrid current limitation and resynchronization algorithms have been proposed to enhance the transient stability of the system. At the end, an experimental test bench has been developed to confirm the theoretical approach
Houari, Azeddine. « Contribution à l'étude de micro-réseaux autonomes alimentés par des sources photovoltaïques ». Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0293/document.
Texte intégralThe actual electrical energy demand focuses on the development of stand-alone electrical systems which leads to the definition of new directives on performances and reliability of the electrical structures, especially those based on renewable energy. The main objective of this work concerns the development of new tools to improve the power quality and the stability of autonomous micro-grid systems. In this aim, new control algorithms based on the concept of differential flatness have been developed. The main advantage of the proposed technique is the possibility of implementing one loop controllers ensuring high dynamic properties. In the same time, it allows accurate prediction of the evolution of all state variables of the system. Concerning the stability of the autonomous micro-grid systems, we proposed tools to deal with instability phenomena either caused by the loss of load information and the resonance phenomenon of the passive filters
Rokrok, Ebrahim. « Controle en grid forming pour les convertisseurs d'électronique de puissance : application aux liaisons courant continus de Haute Tension (HVDC) ». Electronic Thesis or Diss., Centrale Lille Institut, 2022. http://www.theses.fr/2022CLIL0012.
Texte intégralThe rapid development of converter-based devices such as converter-interfaced renewable generations and high-voltage direct-current (HVDC) transmission links is causing a profound change into the very physics of the power system. In this scenario, the power generation is shifted from the pollutant synchronous generators based on nuclear or fossil fuels to converter-based renewable resources. The modeling, control, and stability of the power converters are now one of the focuses of attention for researchers. Today, power converters have the main function of injecting power into the utility grid, while relying on synchronous machines that ensure all system needs (e.g., ancillary services, provision of inertia and reliable power reserves). This operation mode of power converters is called "Grid-following". Grid-following converters have several limitations, such as: inability to operate in a standalone mode, stability issues under weak grids and faulty conditions and also, negative side effect on the system inertia. To tackle these challenges, the grid-forming control as an alternative has shown its appropriate performance that could make this kind of control a promising solution to respond to the system needs and to allow a stable and safe operation of power system with high penetration rate of power electronic converters. In this thesis, a fundamental description of grid-forming control with a simplified quasi-static modeling approach aiming to regulate the converter active power by a voltage source behavior is presented. From the description, several variants of grid-forming strategies are identified that represent some differences in terms of active power dynamic behavior, inertia emulation capability and system frequency support. Hence, the presented grid-forming variants are then classified according to their capabilities/functionalities. From the small-signal stability and robustness point of view, the studied grid-forming controls, which are implemented to a 2-level VSC at first, show their ability to operate under very weak grid conditions. Moreover, the ancillary services such as inertial response and frequency support are appropriately provided to the AC grid. The questions of the grid-forming converters protection against overcurrent and their post-fault synchronization while considering the current limitation are investigated and a new method is proposed to enhance the transient stability of the system. All the obtained results are then extended to a modular multi-level converter (MMC) topology successfully. The use of a grid forming control in an HVDC converter is interesting for the grid to which it is connected due to the inertial effect that can be induced. Therefore, the final part of this thesis evaluates the dynamic performance of an HVDC link interconnecting two AC grids and highlights the proper strategy and requirements for inertia provision
Houari, Azeddine. « Contribution à l'étude de micro-réseaux autonomes alimentés par des sources photovoltaïques ». Electronic Thesis or Diss., Université de Lorraine, 2012. http://www.theses.fr/2012LORR0293.
Texte intégralThe actual electrical energy demand focuses on the development of stand-alone electrical systems which leads to the definition of new directives on performances and reliability of the electrical structures, especially those based on renewable energy. The main objective of this work concerns the development of new tools to improve the power quality and the stability of autonomous micro-grid systems. In this aim, new control algorithms based on the concept of differential flatness have been developed. The main advantage of the proposed technique is the possibility of implementing one loop controllers ensuring high dynamic properties. In the same time, it allows accurate prediction of the evolution of all state variables of the system. Concerning the stability of the autonomous micro-grid systems, we proposed tools to deal with instability phenomena either caused by the loss of load information and the resonance phenomenon of the passive filters
Machado, Martínez Juan Eduardo. « Some Problems on the Analysis and Control of Electrical Networks with Constant Power Loads On Existence of Equilibria of Multi-Port Linear AC Networks With Constant-Power Loads An Adaptive Passivity-Based Controller of a Buck-Boost Converter with a Constant Power Load Power-Controlled Hamiltonian Systems : Application Electrical Systems with Constant Power Loads On the Existence and Long-Term Stability of Voltage Equilibria in Power Systems with Constant Power Loads Active Damping of a DC Network with a Constant Power Load : An Adaptive Observer-based Design ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS445.
Texte intégralThe continuously increasing demand of electrical energy has led to the conception of power systems of great complexity that may extend even through entire countries. In the vast majority of large-scale power systems the main primary source of energy are fossil fuels. Nonetheless, environmental concerns are pushing a major change in electric energy production practices, with a marked shift from fossil fuels to renewables and from centralized architectures to more distributed ones. One of the main challenges that distributed power systems face are the stability problems arising from the presence of the so-called Constant Power Loads (CPLs). These loads, which are commonly found in information and communication technology facilities, are known to reduce the effective damping of the circuits that energize them, which can cause voltage oscillations or even voltage collapse. In this thesis, the main contributions are focused in understanding and solving diverse problems found in the analysis and control of electrical power systems containing CPLs. The contributions are listed as follows. (i) Simply verifiable conditions are proposed to certify the non existence of steady states in general, multi-port, alternating current (AC) networks with a distributed array of CPLs. These conditions, which are based on Linear Matrix Inequalities, allow to discard the values of the loads' powers that would certainly produce a voltage collapse in the whole network. (ii) For general models of some modern power systems, including High-Voltage Direct Current transmission networks and microgrids, it is shown that if equilibria exist, then there is a characteristic high-voltage equilibrium that dominates, entry-wise, all the other ones. Furthermore, for the case of AC power systems under the standard decoupling assumption, this characteristic equilibrium is shown to be long-term stable. (iii) A class of port-Hamiltonian systems, in which the control variables act directly on the power balance equation, is explored. These systems are shown to be shifted passive when their trajectories are constrained to easily definable sets. The latter properties are exploited to analyze the stability of their---intrinsically non zero---equilibria. It is also shown that the stability of multi-port DC electrical networks and synchronous generators, both with CPLs, can be naturally studied with the proposed framework. (iv) The problem of regulating the output voltage of the versatile DC buck-boost converter feeding an {em unknown} CPL is addressed. One of the main obstacles for conventional linear control design stems from the fact that the system's model is non-minimum phase with respect to each of its state variables. As a possible solution to this problem, this thesis reports a nonlinear, adaptive controller that is able to render a desired equilibrium asymptotically stable; furthermore an estimate of the region of attraction can be computed. (v) The last contribution concerns the active damping of a DC small-scale power system with a CPL. Instead of connecting impractical, energetically inefficient passive elements to the existing network, the addition of a controlled DC-DC power converter is explored. The main contribution reported here is the design of a nonlinear, observer-based control law for the converter. The novelty of the proposal lies in the non necessity of measuring the network's electrical current nor the value of the CPL, highlighting its practical applicability. The effectiveness of the control scheme is further validated through experiments on a real DC network
Yesuratnam, G. « Development Of Algorithms For Security Oriented Power System Operation ». Thesis, 2007. https://etd.iisc.ac.in/handle/2005/573.
Texte intégralYesuratnam, G. « Development Of Algorithms For Security Oriented Power System Operation ». Thesis, 2007. http://hdl.handle.net/2005/573.
Texte intégralKrishan, Ram. « Stability and optimization of ac/dc power systems ». Thesis, 2018. http://localhost:8080/xmlui/handle/12345678/7707.
Texte intégral« Hybrid AC-High Voltage DC Grid Stability and Controls ». Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.46197.
Texte intégralDissertation/Thesis
Doctoral Dissertation Electrical Engineering 2017
Haldar, Abhijeet, et Vishwarath Bhadauria. « Power System Stability Enhancement by Simultaneous AC-DC Power Transmission ». Thesis, 2012. http://ethesis.nitrkl.ac.in/3262/1/AC-DC_thesis.pdf.
Texte intégral« Modeling and Large Signal Stability Analysis of A DC/AC Microgrid ». Master's thesis, 2018. http://hdl.handle.net/2286/R.I.50493.
Texte intégralDissertation/Thesis
Masters Thesis Engineering 2018
Pirooz, Azad Sahar. « Small-signal Dynamic Stability Enhancement Of A DC-segmented AC Power System ». Thesis, 2014. http://hdl.handle.net/1807/65726.
Texte intégralShah, Masood Hussain. « Small signal model of an HVDC terminal for stability analysis of AC-DC power systems ». 2009. http://hdl.handle.net/1993/21566.
Texte intégralTseng, Tay-Yuan, et 曾泰元. « Dynamic Stability Enhancement of Parallel AC-DC and Multimachine Power Systems Using H-inf Controllers ». Thesis, 1996. http://ndltd.ncl.edu.tw/handle/11470038148356431471.
Texte intégral國立成功大學
電機工程研究所
84
This thesis investigates the robust H-inf optimal control theory to enhance the dynamic stability of two different kinds of power systems. The robust H-inf optimal control theory has been widely applied in power systems in recent years. In this thesis, this theory is used to design the rectifier current regulators (RCR) in a parallel AC-DC power system and the power system stabilizers (PSS) in a multimachine power system to enhance the robust and stable characteristics of both systems. The reduced-order method is employed to perform the analysis of uncertainty of the studied systems in order to make the controllers more robust. In this thesis, torque disturbances and the changes of system operating points are utilized to test the robust characteristics of the systems. From the simulation results, it shows that the designed controllers can effectively stabilize the studied systems.
LEE, SHENG HUNG, et 李勝弘. « Applications of Poincaré Map to Multiple Parallel AC/DC Converters Harmonic Analysis and Power System Stability Problem ». Thesis, 2003. http://ndltd.ncl.edu.tw/handle/30244255641085044042.
Texte intégral國立中正大學
電機工程研究所
91
The power quality studies associated with nonlinear loads and faults occurred in power system have attracted many attentions by engineers and researchers. However, the usefulness proposed by different approaches by such studies are discrepant. The purpose of this paper is to investigate a new method to improve the solution times of solving the problems under study. In this thesis, Poincaré map is used to solve the steady state solutions of multiple six-pulse AC/DC converters based on the theory periodic functions are invariable with time. Then the simulation results of the purposed method is used to compared with those obtained by using MATLAB/Simulink. It is shown that the Poincaré map is efficient to find the steady state solution. In addition, the power system stability problems are studied by the Poincaré map and Limit Cycle approaches to evaluate the solution accuracies and solution times. The Limit Cycle analysis is one of Poincaré map expressions in the high dimension. The simulation results of Limit Cycle are then compared with the traditional Newton-Raphson method.
Visakha, K. « Some Aspects Of Voltage Stability Improvement In Planning And Operation Of Power Systems ». Thesis, 2004. https://etd.iisc.ac.in/handle/2005/1169.
Texte intégralVisakha, K. « Some Aspects Of Voltage Stability Improvement In Planning And Operation Of Power Systems ». Thesis, 2004. http://etd.iisc.ernet.in/handle/2005/1169.
Texte intégral