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Athanasius, Germane Information Technology & Electrical Engineering Australian Defence Force Academy UNSW. "Robust decentralised output feedback control of interconnected grid system." Awarded by:University of New South Wales - Australian Defence Force Academy, 2008. http://handle.unsw.edu.au/1959.4/39591.
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The novel contribution of the thesis is the design and implementation of decentralised output feedback power system controllers for power oscillation damping (POD) over the entire operating regime of the power system. The POD controllers are designed for the linearised models of the nonlinear power system dynamics. The linearised models are combined and treated as parameter varying switched systems. The thesis contains novel results for the controller design, bumpless switching and stability analysis of such switched systems. Use of switched controllers against the present trend of having single controller helps to reduce the conservatism and to increase the uncertainty handling capability of the power system controller design. Minimax-LQG control design method is used for the controller design. Minimax-LQG control combines the advantages of both LQG and H control methods with respect to robustness and the inclusion of uncertainty and noise in the controller design. Also, minimax-LQG control allows the use of multiple integral quadratic constraints to bound the different types of uncertainties in the power system application. During switching between controllers, switching stability of the system is guaranteed by constraining the minimum time between two consecutive switchings. An expression is developed to compute the minimum time required between switchings including the effect of jumps in the states. Bumpless switching scheme is used to minimise the switching transients which occur when the controllers are switched. Another contribution of the thesis is to include the effect of on load tap changing transformers in the power system controller design. A simplified power system model linking generator and tap changing transformer dynamics is developed for this purpose and included in the controller design. The performance of the proposed linear controllers are validated by nonlinear computer simulations and through real time digital simulations. The designed controllers improve power system damping and provide uniform performance over the entire operating regime of the generator.
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Tennakoon, Sankika. "Flicker propagation in radial and interconnected power systems." School of Electrical, Computer and Telecommunications Engineering - Faculty of Informatics, 2008. http://ro.uow.edu.au/theses/96.
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Voltage fluctuations which cause lamp flicker tend to propagate from the point of origin to various parts of a power system exhibiting some level of attenuation depending on factors such as system impedances, composition of loads and frequency components of the fluctuating waveform. Maintaining the flicker levels at various busbars below the planning limits specified by the standards is crucial, and in this regard it is important to develop an insight into the manner in which the flicker propagates via systems operating at different voltage levels. This thesis presents flicker transfer analysis methodologies applicable for radial and interconnected power systems particularly considering the influence of induction motor loads on flicker attenuation.In the first phase of the work, development of the foundations towards flicker transfer analysis methodologies is carried out by investigating the stand-alone behaviour of induction motors that are subjected to regular supply voltage fluctuations. The electrical and mechanical response of induction motors to two types of sinusoidal fluctuations in the supply voltage where (a) a positive or negative sequence sinusoidal frequency component is superimposed on the mains voltage and (b) mains voltage amplitude is sinusoidally modulated are examined. State space representation of induction motors is used to develop a linearised induction motor model describing the response of the stator current and the rotor speed to small voltage variations in the supply voltage. The results from the model reveal that various sub-synchronous and/or super-synchronous frequency components that exist in the supply voltage as small voltage perturbations can influence the dynamic response of the machine in relation to flicker. In particular, oscillations in the electromagnetic torque and rotor speed arising as a result of the applied voltage perturbations are found to be the key influencing factors controlling the stator current perturbations. It has been noted that, the speed fluctuation caused by a superimposed positive sequence voltage perturbation tends to produce extra emf components in the rotor which in turn can reflect back to the stator. This concept of multiple armature reaction has been found to be significant in large motors especially when the superimposed frequencies are closer to the fundamental frequency.The second phase of the work covers the development of systematic methods for evaluation of flicker transfer in radial and interconnected power systems taking the dynamic behaviour of induction motors into account. In relation to radial systems, small signal models are developed which can be used to establish the flicker propagation from a higher voltage level (upstream) to a lower voltage level (downstream) where induction motor loads are connected. Although this method can be applied for regular or irregular voltage fluctuations, emphasis has been given to sinusoidal voltage fluctuations arising from conventional sinusoidal amplitude modulation of upstream voltage. Moreover, the method examines the propagation of sub-synchronous and super-synchronous frequency components that exist in the supply voltage as side bands and hence determines the overall attenuation in the voltage envelope. The contribution of induction motors of different sizes and other influential factors such as system impedance, loading level of the motor are examined. It has been noted that in general higher frequency components of the upstream fluctuating voltage envelope tend to attenuate better at the downstream. A method is also presented which allows aggregation of induction motors at the load busbars in relation to flicker transfer studies.In relation to interconnected systems, a frequency domain approach which can be used to investigate the flicker transfer is presented. This approach can be considered as an extension to the impedance matrix method as described in the literature and can overcome some of the limitations of the latter method. In the proposed approach, induction motor loads are modelled in a more realistic manner to replicate their dynamic behaviour, thus enabling the examination of the frequency dependent characteristics of flicker attenuation due to induction motors and the influence of tie lines in compensating flicker at remote load busbars consisting of passive loads.To verify some of the theoretical outcomes real time voltage waveforms captured from a large arc furnace site have been used, in addition to the experimental work using a scaled down laboratory set up of a radial power system.
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Thompson, Jeffrey Craig. "An expert system for protection system design of interconnected electrical distribution circuits." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-170345/.
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Du, Zhaobin. "Area COI-based slow frequency dynamics modeling, analysis and emergency control for interconnected power systems." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B4175783X.
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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.
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With ambitions of reducing the environmental pollution, power systems integrate larger shares of Renewable Energy Sources (RES) to phase out conventional thermal and nuclear generators. Since RES (such as wind and solar power) are connected to the grid through power electronics devices, they do not inherently contribute to system inertia. With decreasing inertia, the Instantaneous Frequency Deviation (IFD), which follows a power unbalance, is significantly impacted. Frequency Containment Reserves (FCR) are designed to provide a fast dynamic response, counteract power imbalances and stabilize the frequency within a short time interval. Besides inertia, the significant factors affecting frequency behavior are the available amount of FCR and the capability of their fast and stable response. System operators define the list of requirements that a generating unit has to satisfy to participate in FCR. Generators, which are the major part of FCR, have different governors and turbines properties. This study assesses the dynamical performance of typical generators in both open-loop testing and closed-loop varying inertia systems. The goal is to evaluate if specific FCR requirements present a sufficient condition for the desired response, and which governor properties are capable of satisfying them. As an additional, and sometimes necessary, support to FCR, HVDC interconnections are utilized in the form of Emergency Power Control (EPC). This thesis investigates which of the EPC methods performs appropriately in terms of IFD improvement, closed-loop stability, and power and energy provided. The analysis is a continuation from the previous investigation on FCR, and mainly compare two EPC methods related to Nordic Power System (NPS) test case: ramp/step method which is currently implemented in the NPS, and droop frequency-based EPC, proposed by this study for the future operation in the NPS. Apart from ensuring a proper system frequency response, the influence of implemented HVDC supplementary active power control is analyzed to rotor angle stability. In further, this thesis presents a comprehensive analysis of the impact that proposed HVDC supplementary power control has on the linearized dynamics of power systems. By building a generic system, this analytical study is the first of its kind that includes both higher order generator dynamics, and local angle/frequency input of the controller. The methodological approach here analytically formulates the impact the HVDC supplementary control has mainly on the generator synchronizing and damping torque components. The positive impact of the droop frequency-based HVDC power support is highlighted using both single and multi-machine systems. In that way, the implementation of desired droop frequency-based HVDC control to mainly improve system frequency is motivated furthermore. It shows that a proper HVDC supplementary control may impose the various positive impacts for future variable and low inertia scenarios, and ensure a proper power system sustainability.QC 20200907
multiDC - Advanced Control and Optimization Methods for AC and HVDC Grids
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Guo, Jianping. "Sliding Mode Based Load Frequency Control for an Interconnected Power System with Nonlinearities." Cleveland State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=csu1435857616.
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Du, Zhaobin, and 杜兆斌. "Area COI-based slow frequency dynamics modeling, analysis and emergency control for interconnected power systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B4175783X.
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Abayateye, Julius. "Study of bundling reactive power and transaction charges with generation cost in an interconnected power system a thesis presented to the faculty of the Graduate School, Tennessee Technological University /." Click to access online, 2009. http://proquest.umi.com/pqdweb?index=0&did=1759989191&SrchMode=1&sid=2&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1268411282&clientId=28564.
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Saeidpour, Parizy Ehsan. "Electrical Energy Retail Price Optimization for an Interconnected/Islanded Power Grid." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1512463830323059.
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Bi, Tianshu. "Distributed intelligent system for on-line fault section estimation of large-scale power networks." Click to view the E-thesis via HKUTO, 2002. http://sunzi.lib.hku.hk/hkuto/record/B42576714.
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畢天姝 and Tianshu Bi. "Distributed intelligent system for on-line fault section estimation oflarge-scale power networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B42576714.
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Bank, Jason Noah. "Propagation of Electromechanical Disturbances across Large Interconnected Power Systems and Extraction of Associated Modal Content from Measurement Data." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/73008.
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Changes in power system operating conditions cause dynamic changes in angle and frequency. These disturbances propagate throughout the system area with finite speed. This propagation takes the form of a traveling wave whose arrival time at a particular point in the system can be observed using a wide-area measurement system (WAMS). Observations of these waves both through simulation and measurement data have demonstrated several factors that influence the speed at which a disturbance propagates through a system. Results of this testing are presented which demonstrate dependence on generator inertia, damping and line impedance. Considering a power system as an area with and uneven distribution of these parameters it is observed that a disturbance will propagate throughout a system at different rates in differing directions. This knowledge has applications in locating the originating point of a system disturbance, understanding the overall dynamic response of a power system, and determining the dependencies between various parts of that system.
A simplified power system simulator is developed using the swing equation and system power flow equations. This simplified modeling technique captures the phenomenon of traveling electromechanical waves and demonstrates the same dependencies as data derived from measurements and commercial power system simulation packages. The ultimate goal of this research is develop a methodology to approximate a real system with this simplified wave propagation model. In this architecture each measurement point would represent a pseudo-bus in the model. This procedure effectively lumps areas of the system into one equivalent bus with appropriately sized generators and loads. With the architecture of this reduced network determined its parameters maybe estimated so as to provide a best fit to the measurement data. Doing this effectively derives a data-driven equivalent system model. With an appropriate equivalent model for a given system determined, incoming measurement data can be processed in real time to provide an indication of the system operating point. Additionally as the system state is read in through measurement data future measurements values along the same trajectory can be estimated. These estimates of future system values can provide information for advanced control and protection schemes.
Finally a procedure for the identification and extraction of inter-area oscillations is developed. The dominant oscillatory frequency is identified from an event region then fit across the surrounding dataset. For each segment of this data set values of amplitude, phase and damping are derived for each measurement vector. Doing this builds up a picture of how the oscillation evolves over time and responds to system conditions. These results are presented in a graphical format as a movie tracking the modal phasors over time. Examples derived from real world measurement data are presented.Ph. D.
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Habtay, Yehdego Tekeste. "Advanced static VAr compensator for direct on line starting of induction motors in an interconnected offshore power system." Thesis, Heriot-Watt University, 2002. http://hdl.handle.net/10399/371.
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Chaudhary, Arvind K. S. "Protection system representation in the Electromagnetic Transients Program." Diss., This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-07282008-134541/.
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Gencoglu, Cihangir. "Assessment Of The Effect Of Hydroelectric Power Plants'." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612165/index.pdf.
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The Turkish TSO (TEIAS) has been leading a project that aims the synchronous interconnected operation of the Turkish Power System and the ENTSO-E CESA (former UCTE) System. For this purpose, this study concentrates on the specific problems related to the electromechanical systems of large size hydroelectric power plants regarding low frequency inter area oscillations, which are prone to occur once the interconnected operation is established. The expected frequency of inter area oscillations after interconnected operation is close to 0.15 Hz, which is in the frequency range of the speed governing structures of turbines, as explained in the first two sections of the thesis. In the third section, the nonlinear turbine governor model used throughout the study is explained. In the following part, the governor parameter tuning study with regard to the defined performance objectives is explained. Afterwards, the effect of the retuned governor settings of the sample hydroelectric power plants on a simple multi machine power system is shown. Following that, the system wide effect of removing the sources of negative damping, which are strongly dependent on the governor settings of the major hydroelectric power plants of the Turkish Power System, is shown. In the final part, conclusions are made on the operation of the hydroelectric power plants regarding the frequency stability of the system after synchronous interconnected operation of the Turkish Power System and the ENTSO-E CESA System.
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Adekola, Olawale Ibrahim. "Design and development of a smart inverter system." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2195.
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Thesis (MTech (Electrical, Electronic and Computer Engineering))--Cape Peninsula University of Technology, 2015.The growing interest in the use of solar energy to mitigate climate change, reduction in the cost of PV system and other favourable factors have increased the penetration of the PV(Photovoltaic) systems in the market and increase in the worldwide energy supply. The main component in a DG is a smart inverter connected in a grid-tied mode which serves as a direct interface between the grid and the RES (Renewable Energy System). This research work presents a three phase grid-tied inverter with active and reactive power control capabilities for renewable energy sources (RES) and distributed generators (DG). The type of the inverter to be designed is a Voltage Source Inverter (VSI). The VSI is capable of supplying energy to the utility grid with a well regulated DC link at its input. The solution this project proposes is an implementation of the designed filter to effectively reduce the harmonics injected into the grid to an acceptable value according to standards and also an approach to control the real and reactive power output of the inverters to help solve the problems of instability and power quality of the distribution system. The design, modelling and simulation of the smart inverter system is performed in MATLAB/SIMULINK software environment. A 10 kW three-phase voltage source inverter system connected to the utility grid was considered for this research. Series of simulations for the grid-connected inverter (GCI) model was carried out using different step changes in active and reactive power references which was used to obtain the tracking response of the set power references. The effectiveness of the control system which was designed to track the set references and supply improved power quality with reduced current ripples has been verified from the simulation results obtained.
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Al-Busaidi, Adil G. "Automatic generation control of the Petroleum Development Oman (PDO) and the Oman Electricity Transmission Company (OETC) interconnected power systems." Thesis, Teesside University, 2012. http://hdl.handle.net/10149/263268.
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Petroleum Development Oman (PDO) and Oman Electricity Transmission Company (OETC) are running the main 132kV power transmission grids in the Sultanate of Oman. In the year 2001, PDO and OETC grids were interconnected with a 132kV Over head transmission line linking Nahada 132kV substation at PDO's side to Nizwa 132kV sub-station at OETC's side. Since then the power exchange between PDO and OETC is driven by the natural impedances of the system and the frequency and power exchange is controlled by manually re-dispatching the generators. In light of the daily load profile and the forecasted Gulf Cooperation Council (GCC) states electrical interconnection, it is a great challenge for PDO and OETC grids operators to maintain the existing operation philosophy. The objective of this research is to investigate Automatic Generation Control (AGC) technology as a candidate to control the grid frequency and the power exchange between PDO and OETC grid. For this purpose, a dynamic power system model has been developed to represent PDO-OETC interconnected power system. The model has been validated using recorded data from the field which has warranted the requirement of refining the model. Novel approaches have been followed during the course of the model refining process which have reduced the modelling error to an acceptable limit. The refined model has then been used to assess the performance of different AGC control topologies. The recommended control topologies have been further improved using sophisticated control techniques like Linear Quadratic Regulator (LQR) and Fuzzy Logic (FL). Hybrid Fuzzy Logic Proportional Integral Derivative (FLPID) AGC controller has produced outstanding results. The FLPID AGC controller parameters have then been optimised using Multidimensional Unconstrained Nonlinear Minimization function (fminsearch) and Particle Swarm Optimisation (PSO) method. The PSO has been proved to be much superior to fminsearch function. The robustness of the LQR, the fminsearch optimized FLPID and the PSO FLPID optimized AGC controllers has been assessed. The LQR robustness found to be slightly better than the FLPID technique. However the FLPID supercedes the LQR due to the limited number of field feedback signals in comparison to the LQR. Finally, a qualitative assessment of the benefits of the ongoing GCC interconnection project on PDO and OETC has been done through modelling approach. The results proved that the GCC interconnection will bring considerable benefits to PDO and OETC but the interconnection capacity between PDO and OETC needs to be enhanced. However, the application of AGC on PDO and OETC will alleviate the PDO-OETC interconnection capacity enhancement imposed by the GCC interconnection.
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Gessesse, Belachew Bantyirga [Verfasser], István [Akademischer Betreuer] Erlich, and Holger [Akademischer Betreuer] Hirsch. "Integration of Large Wind Farms into Weak Power Grids – Emphasis on the Ethiopian Interconnected System (ICS) / Belachew Bantyirga Gessesse. Gutachter: Holger Hirsch. Betreuer: István Erlich." Duisburg, 2013. http://d-nb.info/1041224370/34.
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GIMENEZ, JOSE-LUIS. "Contribution a la decomposition de systemes interconnectes par programmation dynamique non serielle : application a des systemes de puissance." Toulouse 3, 1989. http://www.theses.fr/1989TOU30049.
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Viljoen, Machiel. "'n Omvattende nasionale bestuursraamwerk vir kragstelselbelemmering deur aaneengeskakelde ontwrigting van kragontwikkeling in Suid-Afrika / Machiel Viljoen." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9542.
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This desertation shows that a unique class of network disruption exists that
can be regarded in isolation of other classes of network disturbances, namely
cascade disruption of generation (COG). This class of disturbance is being
defined in terms of the cascading effect that it exhibits in terms of the
disruption of power generating units in an interconnected power system.
Through a literature survey it is shown that a lack of formal acknowledgement
exists in the recognition of this class of disturbance both locally and abroad,
and that therefore there is a general absence of a policy framework to
manage the threat that is associated with the cascade disruption of
generation.
The analysis of the records of such events in the Southern African power pool
are analised, and the properties and characteristics of COG events are
explored. The extent of the threat to the interconnected power system that is
posed by COG, as a phenomenon, is quantified in the conte·xt of industry
practice and weaknesses are identified. It is shown that the occurrence of this
class of event is not entirely random, and that statistical methods can be used
in the development of mitigation strategies.
A management framework is developed with metrics for the monitoring,
evaluation and trending of the phenomenon, and to evaluate the ongoing risk.
Roles and responsibilities are sugested and a outline for the systematic
investigation of such events is developed.
In the conclusion, the possible benefits of the an COG managenent
framework are discussed and scope for future work in this regard is
suggested.Thesis (MIng (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2013
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Barrientos, Mujica Luis Germán. "Benefícios associados à operação coordenada do sistema interligado nacional junto com as usinas binacionais de Corpus e Yacyretá = Benefits associated with the coordinated operation of the Brazilian national interconnected system along with the binational hydro plants of Corpus and Yacyretá." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259878.
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Orientadores: Secundino Soares Filho, Monica de Souza ZambelliDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-21T13:07:22Z (GMT). No. of bitstreams: 1 BarrientosMujica_LuisGerman_M.pdf: 2072271 bytes, checksum: 0bd4e2be251a8462886f62e46c8e5f32 (MD5) Previous issue date: 2012
Resumo: O presente trabalho apresenta uma avaliação do impacto da operação das usinas hidrelétricas brasileiras que compõem o Sistema Interligado Nacional (SIN) sobre as usinas hidrelétricas binacionais de Corpus e Yacyretá. Alguns dos benefícios que apresentam a interligação elétrica e a integração energética entre os países integrantes do MERCOSUL podem ser um maior aproveitamento do potencial hidráulico, a redução do custo da eletricidade, o aproveitamento da energia excedente, entre outros. Foram considerados dois estudos de caso com dados oficiais do Programa Mensal da Operação (PMO) do SIN referentes a setembro de 2011, considerando o planejamento da expansão do parque gerador e da transmissão até dezembro de 2015. As soluções foram fornecidas pelo modelo ODIN (Otimização do Despacho Interligado Nacional), uma abordagem baseada em otimização determinística e não linear com vazões previstas e atualizadas a cada intervalo de tempo, no que se denomina Modelo de Controle Preditivo (MCP). Dessa forma é possível uma representação detalhada e individualizada das usinas hidrelétricas do sistema, viabilizando a análise pretendida. A avaliação do desempenho do sistema nos estudos de caso se deu através de simulação sobre 64 cenários históricos, considerando a série histórica de vazões de 1931 a 1998. Existem cenários em que a operação coordenada concentrou benefícios nas usinas brasileiras, e cenários em que a operação coordenada concentrou benefícios nas usinas binacionais. Porém, considerando a geração hidrelétrica média total, foi obtido um aumento de geração de 12,27 MW médios, ou 107.485,2 MWh por ano, o que significa que operando de maneira coordenada haverá um ganho de cerca de R$ 10.748.520,00 por ano, considerando um valor médio de 100 R$/MWh
Abstract: This work presents an assessment of the impact of the operation of the hydro power plants that comprise the Brazilian National Interconnected System (SIN) over the binational hydro power plants of Corpus and Yacyretá. Some of the benefits that arise from the electrical interconnection and the energy integration between the countries members of MERCOSUL may be a better exploitation of the hydraulic potential, a reduction of the cost of electricity, and the utilization of surplus energy, among others. Two case studies using official data from the Monthly Operation Program (PMO) of SIN referred to September 2011 were considered, taking into consideration the generation and transmission expansion plan until December 2015. The solutions were provided by the ODIN model, an operation approach based on deterministic and nonlinear optimization with forecasted inflows, and updated at each time interval, which is known as Model Predictive Control (MPC). By this way, a detailed and individualized representation of the hydro plants of the system is possible, allowing the required analysis. The performance evaluation of the system in the case studies were calculated through the simulation over 64 historical scenarios, taking into consideration the historical inflow records from 1931 to 1998. There were hydrological scenarios where the coordinated operation concentrates benefits in the Brazilian hydro plants, and scenarios where the coordinated operation concentrates benefits on the binational plants. However, considering the total average hydroelectric generation, an increase on generation of 12,27 MW was obtained, or 107.485,2 MWh per year, which means that operating the system on a coordinated way there will be a benefit of approximately R$ 10.748.520,00 per year, considering an average value of energy of 100 R$/MWh
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica
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Colombet, Laurent. "Parallélisation d'applications pour des réseaux de processeurs homogènes ou hétérogènes." Grenoble INPG, 1994. http://tel.archives-ouvertes.fr/tel-00005084.
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Le but de cette these est d'etudier et developper des methodes pour la parallelisation efficace des applications scientifiques sur machines paralleles a memoire distribuee. Dans une premiere partie nous presentons deux bibliotheques de fonctions de communication PVM ((\it Parallel Virtual Machine)) et MPI ((\it Message Passing Interface)). Ces dernieres fournissent une portabilite des programmes sur la grande majorite des machines paralleles, mais aussi sur des reseaux d'ordinateurs heterogenes. Cette partie illustre le probleme de la mesure des performances pour des reseaux de processeurs heterogenes. Ceci nous a amene a adapter le calcul du facteur d'acceleration et de l'efficacite afin de pouvoir evaluer les performances d'un algorithme sur un reseau de processeurs heterogenes. La deuxieme partie est consacree a l'etude de bibliotheques numeriques paralleles, comme ScaLAPACK, et au developpement d'une methode etudiee de maniere theorique, mais peu utilisee en pratique pour augmenter les performances des fonctions de ces bibliotheques : le recouvrement calcul/communication. L'idee generale consiste a anticiper les communications, notamment en pipelinant l'envoi des messages. Des resultats experimentaux sur machines Cray T3D et IBM SP1, permettent de valider les etudes theoriques effectuees sur des algorithmes de base de ces bibliothequesThe aim of this thesis is to study and develop efficient methods for parallelization of scientific applications on parallel computers with distributed memory. In the first part we present two libraries of PVM((\it Parallel Virtual Machine)) and MPI ((\it Message Passing Interface)) communication tools. They allow implementation of programs on most parallel machines, but also on heterogeneous computer networks. This chapter illustrates the problems faced when trying to evaluate performances of networks with heterogeneous processors. To evaluate such performances we modified and adapted the concepts of speed-up and efficiency to account for heterogeneity. The second part deals with a study of parallel application libraries such as ScaLAPACK and with the development of communication masking techniques. The general concept is based on communication anticipation, in particular by pipelining message sending operations. Experimental results on Cray T3D and IBM SP1 machines validates the theoretical studies performed on basic algorithms of the libraries discussed above
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Al-Hinai, Amer. "Voltage collapse prediction for interconnected power systems." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1639.
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Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains xii, 94 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 66-67).
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Alhaj, Ali Mounes. "Impact of wind power on weakly interconnected systems." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534633.
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Harsan, Horea. "Analyse cyclique de sécurité : approche temps réel et intégration dans la gestion prévisionnelle." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0166.
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L'un des aspects important de la conception et de l'exploitation des grands réseaux de transport et d'interconnexion est le maintien de la sécurité du système. Cette sécurité concerne aussi bien les limites thermiques sur les ouvrages de transport que les limites de tension aux noeuds du réseau (contraintes d'isolation et de stabilité). A cet effet, le développement de méthodes nouvelles qui permettront à l'opérateur d'exploiter le réseau de façon à ce qu'aucun incident ne puisse causer les dépassements de limites de sécurité du système, est de plus en plus une nécessité. Cette thèse présente un algorithme général pour rendre plus efficace l'naisse de sécurité et donc permettre une analyse réellement systématique des incidents. Cet outil est basé sur l'utilisation des informations intrinsèquement contenues dans les résultats d'une analyse de sécurité systématique. Ces dernières peuvent être utilisées à des instants suivants en temps réel ou pour construire la carte des contraintes sur un horizon journalier. Une partie importante de cette thèse est consacrée à l'intégration de l'analyse de sécurité cyclique dans la réalisation du couplage production-réseau (introduction de la sécurité réseau dans la gestion prévisionnelle). Les résultats obtenus sur des données de planification issues du dispatching national montrent un gain de temps considérable acquit grâce à l'analyse cyclique. Elle se prête également bien aux analyses successives utilisées dans les optimisations du plan de tension en sécurité N et N-1. Un des chapitres de cette thèse traite l'analyse cyclique de sécurité en parallèle. La validation de la stratégie de parallélisation choisie a été faite sur un ordinateur parallèle CRAY
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Yao, Ziwen. "Régulateur adaptatif robuste pour les liaisons de transport a courant continu en haute tension." Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL051N.
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Cette thèse présente un ensemble de méthodes de synthèse du contrôle commande adaptatif robuste dans le domaine fréquentiel pour les liaisons de transport à courant continu en haute tension destine à améliorer la stabilité en basse fréquence du réseau. Cet ensemble de méthodes consiste en une méthode de modélisation des réseaux d'interconnexion, une méthode d'analyse de stabilité pour les réseaux d'interconnexion, une approche d'identification des réseaux électriques et une approche de synthèse du régulateur adaptatif-robuste. La méthode de simplification de modélisation des réseaux d'interconnexion est fondée sur des propriétés algébriques: l'y-symétrie et la possibilité de découplage de la matrice de caractéristiques de fréquence des réseaux. Basé sur ces propriétés et sur le critère de stabilité de Nyquist généralisé, un critère de stabilité est proposé pour les réseaux d'interconnexion. L'approche d'identification des réseaux électriques est fondée sur ces propriétés algébriques et est réalisée à l'aide de la transformation de Fourier. Afin de montrer les avantages ainsi que les inconvénients des méthodes proposées cette thèse est illustrée par différents résultats de simulation numérique. Dans ces simulations numériques sont étudiés les phénomènes d'interaction torsionnelle entre la liaison TCCHT IFA 2000 et les turboalternateurs voisins
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Jiang, Haibo. "Robust control strategies for the transient control of interconnected power systems." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/15728.
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Rajasekaran, Vinod. "Power delivery in systems with lossy cables or interconnects." Diss., Available online, Georgia Institute of Technology, 2003:, 2003. http://etd.gatech.edu/theses/available/etd-11252003-095456/unrestricted/rajasekaranvinod200312phd.pdf.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2004.Dr. Bonnie S. Heck, Committee Chair; David G. Taylor, Committee Member; Thomas. G. Habetler, Committee Member; Linda M. Wills, Committee Member; Eric Johnson, Committee Member. Includes bibliography.
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Delbone, Edval. "Atenuação de Harmônicos nos Geradores Síncronos Provenientes das Cargas Não Lineares Utilizando Geradores de Indução." Universidade Federal de Uberlândia, 2012. https://repositorio.ufu.br/handle/123456789/14310.
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This work demonstrates the theoretical and experimental feasibility of a induction
generator to work as an attenuator of the harmonics in main generators of on the electric
power system, i.e., the synchronous generators. The induction and synchronous
machines were analyzed in physical terms and established mathematical modeling
in the frequency domain in order to prove the purpose of the thesis. Computer simulations
were also carried out in the time domain and laboratory tests were made
to check levels of attenuation of current harmonics (THDi) in accordance with the
maximum standardized voltage harmonic distortion (THDv). Furthermore, this work
presents a study of technical and economical feasibility of a typical application.Este trabalho demonstra a viabilidade teórica e experimental de um gerador de indução funcionar como um atenuador dos harmônicos nos geradores principais do sistema elétrico de potência, ou seja, os geradores síncronos. Foram analisadas as máquinas de indução e síncronas do ponto de vista físico e estabelecidas modelagens matemáticas no domínio da frequência, a fim de comprovar o objetivo da tese. Foram realizadas também´em, simulações computacionais no domínio do tempo e ensaios em laboratório para verificar os n´níveis de atenuação de harmônicos de corrente (THDi) em conformidade com os limites máximos de distorções harmônicas de tensão (THDv) normalizados. Apresenta-se também neste trabalho um estudo de viabilidade técnica e econômica de uma aplicação típica.
Doutor em Ciências
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麥禮安 and Lai-on Mak. "Fuzzy logic statcom controller design with genetic algorithm application for stability enhancement of interconnected power systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B42128699.
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Mak, Lai-on. "Fuzzy logic statcom controller design with genetic algorithm application for stability enhancement of interconnected power systems." Click to view the E-thesis via HKUTO, 2000. http://sunzi.lib.hku.hk/hkuto/record/B42128699.
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Rakhshani, Elyas. "Analysis and control of multi–area HVDC interconnected power systems by using virtual inertia." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/404614.
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Virtual inertia is known as an inevitable part of the modern power systems. Recent trend of research is oriented in different methods of emulating virtual inertia in different part of the systems. This dissertation is focused on modelling, analysing and application of virtual inertia concept in frequency control and Automatic Generation Control (AGC) issue in high level control AC/DC interconnected power systems. Since the virtual inertia is provided by advanced control concepts of power electronic based components, the HVDC links are the main focus of this dissertation for emulating inertia.
AGC in a multi-area power system during load and resource variation is known as a very important mechanism that could facilitate various tasks like: frequency restoration, tie-line power control between authority areas and economic dispatch of generation units. The AGC concept is known as higher level control at the transmission level. This higher level control will generate the set-points for all the local components, like generators or power converter stations, which are under control by their local controllers.
In this thesis two different methods for emulating virtual inertia are proposed and introduced in AGC modelling and control of AC/DC interconnected power systems.
The first method which is one of the common methods for emulating inertia in various filed of applications, is derivative control technique. In this thesis, derivative control technique is used for higher level application of inertia emulation. This
method of inertia emulation is developed for two-area AGC system which is connected by parallel AC/DC transmission lines. Based on the proposed technique, the dynamic effect of inertia emulated for frequency and active power control of interconnected systems are evaluated. The effects of frequency measurements delay and Phase Locked Loop (PLL) effects are also considered by introducing a second-order function. Simulations performed by Matlab software demonstrate how virtual inertia emulation can effectively improve the performance of the power system. A detailed eigenvalue and sensitivity analyses have been also performed to support the positive effects of the proposed method.
Since the first method is based on derivation for grid frequency, the measurement of frequency is very important and application of different method for frequency measurements like PLL will bring some limitations for this method. Therefore, as an ultimate solution, the second method for virtual inertia emulation is introduced in this thesis. The second method is based on Virtual Synchronous Power (VSP) concept. The concept of VSP to simulate the dynamic effects of inertia emulations by HVDC links for higher level control applications is introduced and reflected in the multi-area AGC model. By using this proposed combination in AGC model, the dynamic performance of the systems shows a significant improvement. The active power loop control on VSP based HVDC link has second-order characteristic which make a simultaneous enabling of damping and inertia emulations into the system. Trajectory sensitivities and eigenvalue analyses are used to analyse the effects of VSP on the system stability. The effectiveness of proposed concept on dynamic improvements is tested through Matlab simulation of multi-area test system.
Finally, it became clear that virtual inertia will add additional degree of freedom to the system dynamics which makes a considerable improvement in first overshoot in addition to damping characteristics of HVDC links. Comparing the results of these two different methods of inertia emulation shows that VSP technique has better performance with several advantages for emulating the inertia. In the VSP technique, PLL and frequency estimation are not required. Also considering the fact that simultaneous damping and inertia could be emulated, a powerful method based on VSP for improving the system dynamics during the contingencies is proposed.El concepto de inercia virtual se está convirtiendo en una parte imprescindible de los sistemas de energía modernos y en la actualidad hay diferentes líneas de investigación orientadas a estudiar diferentes métodos de emulación de inercia virtual en diferentes partes del sistema.Esta tesis doctoral se centra en el modelado, análisis y aplicación del concepto de inercia virtual en el control de frecuencia y en el control automático de generación (AGC), los cuales son elementos clave en el control de alto nivel de los sistemas eléctricos interconectados AC / DC.Dada la evolución tanto en las topologías, como en las prestaciones de control de los convertidores electrónicos de potencia, los enlaces HVDC y el control a alto nivel de los dispositivos implicados para emular inercia constituirán el foco principal de esta tesis doctoral.El AGC es un mecanismo muy útil en un sistema de potencia multi-zona durante, sobre todo cuando hay variaciones en la carga o en la generación, ya que puede facilitar diversas tareas como: la restauración de frecuencia, control de potencia de líneas de enlace entre las áreas y el despacho económico de los sistemas de generación. En este contexto en AGC, dada su condición de control a alto nivel, generará las consignas para todos los elementos locales, tales como generadores o estaciones de conversión de energía, que están bajo el control de sus controladores locales.En esta tesis se proponen dos métodos diferentes para emular inercia virtual, los cuales se introducirán, se modelarán y se aplicarán al control de sistemas de potencia AC / DC interconectados. El primer método, que es uno de los métodos más comunes para la emulación de inercia en otras aplicaciones, es la técnica del control derivativo. En esta tesis, esta técnica se utiliza para llevar a cabo la emulación de inercia a alto nivel. Éste método de emulación de inercia se ha desarrollado para un sistema AGC de dos área que está interconectado mediante líneas de transmisión de CA / CC en paralelo. Sobre la base de la técnica propuesta, el efecto dinámico de la inercia emulada sobre el control de frecuencia y potencia activa será formulado y evaluado. Los efectos del retardo mediciones de frecuencia y los efectos del bucle de sincronización (PLL) también se consideran en el análisis y posterior ensayo. Las simulaciones llevadas a cabo demostrarán cómo la emulación de inercia virtual puede mejorar efectivamente el rendimiento del sistema de potencia.Dado que el primer método se basa en la derivación de la frecuencia de red, la medición de la frecuencia es muy importante y la aplicación de los métodos de medida de la misma, como las PLL, conlleva algunas limitaciones en la aplicación y respuesta del mismo. Por lo tanto, como una solución definitiva, se introduce el segundo método para la emulación de inercia virtual en esta tesis. El segundo método se basa en el concepto de energía síncrona virtual (VSP). El concepto de VSP, el cual permite simular los efectos dinámicos de las emulaciones de inercia por enlaces HVDC, se presentará y aplicará en sistemas de control de alto nivel, aplicándolo finalmente en el modelo AGC multi-zona. Tal y como se demostrará, mediante el uso de esta combinación propuesta en el modelo de AGC, el comportamiento dinámico de los sistemas muestra una mejora significativa. El control de bucle de potencia activa en el enlace HVDC basado en el VSP tiene una característica de segundo orden que genera una respuesta instantánea y permite controlar la amortiguación y la inercia en el sistema. La eficacia de concepto propuesto en las mejoras dinámicas se probará en plataformas de simulación que representarán un sistema multi-zona. Por último, se demostrará que la inercia virtual añade un grado de libertad adicional a la dinámica del sistema, lo cual ayuda a controlar el sobre pico así como el amortiguamiento en los transitorios en los enlaces HVDC.
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Iindombo, Julia Dimbulukweni. "Efficiency plan for large interconnected urban ring main network under contingency conditions." Thesis, Cape Peninsula University of Technology, 2011. http://hdl.handle.net/20.500.11838/1185.
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Thesis (MTech(Electrical Engineering))--Cape Peninsula University of Technology, 2011In a situation, where there is a shortage of power generation or the power stations are operating with a very low reserve margin, as is typically the current position in South Africa, there is a need to operate distribution network at the highest possible efficiency by utilising network power loss reduction techniques. Such techniques are especially important when contingencies occur as they tend to increase loss, reduce efficiencies and cause power supplies to such networks to increase. This increase can cause the network or multiples of such networks to be load shed as the power stations do not have the reserve margins to meet this increased demand. The ideal situation would thus be to minimise network loss and in so doing decrease the amount of power needed and possibly avoid load shedding. Thus, there is a need to study efficiency, network loss reduction under contingency conditions and this is the focus of the research. Most large urban distribution networks are operated as ring main networks. Ring networks are considered to have less power loss. However, a major component in a ring network can cause the loss to substantially increase; resulting in power shortage in the network. There is an urgency to eliminate high network loss. An efficiency plan was developed for a large ring network that reduces the loss so that its input power can be decreased. In this way, the available power existing due to the contingency can be more evenly spread, and the number of ring main networks to be load shed could be reduced.
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Rodrigues, Alcantaro Lemes. "Redes neurais artificiais aplicadas na previsão de preços do mercado spot de energia elétrica." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/86/86131/tde-12082010-213202/.
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A comercialização de energia elétrica no Brasil e no mundo sofreu diversas modificações nos últimos 20 anos. Com o objetivo de alcançar o equilíbrio econômico entre oferta e demanda do bem chamado eletricidade, os agentes deste mercado seguem as regras definidas pela sociedade (governo, empresas e consumidores) e também as leis da natureza (hidrologia). Para tratar de problemas tão complexos, estudos são realizados na área da heurística computacional. O objetivo deste trabalho é elaborar um software de previsão de preços do mercado spot utilizando redes neurais artificiais (RNA). As RNA são muito utilizadas em diversas aplicações, principalmente em heurística computacional, nas quais sistemas não lineares apresentam desafios computacionais difíceis de serem superados devido ao efeito da maldição da dimensionalidade. Tal maldição se deve pelo fato do poder computacional atual não ser suficiente para processar problemas com elevada combinação de variáveis. O problema de prever os preços do mercado spot depende de fatores como: (a) a previsão de demanda (carga); (b) a previsão da oferta (reservatórios, regime de chuvas e clima), fator de capacidade; e (c) o equilíbrio da economia (precificação, leilões, influência de mercados externos, política econômica, orçamento governamental, política governamental). Estes fatores são utilizados na construção do sistema de previsão e os resultados de sua eficácia são testados e apresentados.The commercialization of electricity in Brazil as well as in the world has undergone several changes over the past 20 years. In order to achieve an economic balance between supply and demand of the good called electricity, stakeholders in this market follow both rules set by society (government, companies and consumers) and set by the laws of nature (hydrology). To deal with such complex issues, various studies have been conducted in the area of computational heuristics. This work aims to develop a software to forecast spot market prices in using artificial neural networks (ANN). ANNs are widely used in various applications especially in computational heuristics, where non-linear systems have computational challenges difficult to overcome because of the effect named curse of dimensionality. This effect is due to the fact that the current computational power is not enough to handle problems with such a high combination of variables. The challenge of forecasting prices depends on factors such as: (a) foresee the demand evolution (electric load); (b) the forecast of supply (reservoirs, hydrology and climate), capacity factor; and (c) the balance of the economy (pricing, auctions, foreign markets influence, economic policy, government budget and government policy). These factors are considered be used in the forecasting model for spot market prices and the results of its effectiveness are tested and huge presented.
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Erlich, I. Fischer A. U. "Fast Assessment of Small-Signal Oscillatory Stability in Large Interconnected Power Systems, Balkan Power Conference BPC 2002, June 2002, Belgrade, Yugoslavia." Gerhard-Mercator-Universitaet Duisburg, 2003. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-04142003-140806/.
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This paper deals with suitable approaches for fast assessment of oscillatory stability of large interconnected power systems within power system operation. Beside voltage stability and transient stability, oscillatory stability has to be assessed, too. It can be shown, that parallel eigenvalue computation using a parallel variant of Arnoldi method can reduce the time necessary for eigenvalue computation of large power systems.
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Murray, William Norman. "Energy wheeling viability of distributed renewable energy for industry." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2730.
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Thesis (Master of Engineering in Electrical Engineering))--Cape Peninsula University of Technology, 2018.Industry, which forms the lifeblood of South Africa’s economy, is under threat as a result of increased electricity pricing and unstable supply. Wheeling of energy, which is a method to transport electricity generated from an Independent Power Producer (IPP) to an industrial consumer via the utility’s network, could potentially address this problem. Unlike South Africa’s electricity landscape, which is highly regulated and monopolized by Eskom, most developed countries have deregulated their electricity market, which has led to greater competition for electricity supply. This thesis, presents an evaluation of the economic viability and technical concerns arising from third party transportation of energy between an IPP and an industrial consumer. IPP’s are able to generate electricity from various renewable distributed generation (DG) sources, which are often physically removed from the load. In practice, electricity could be generated by an IPP and connected to a nearby Main Transmission Substation (MTS) in a region with high solar, wind or hydropower resources and sold to off-takers a few hundred kilometres away. Using two software simulation packages, technical and economic analysis have been conducted based on load data from two industrial sites, to determine the viability of wheeling energy between an IPP and off-taker. The viability will be evaluated based on levelized cost of electricity (LCOE); net present cost (NPC); DG technology; distance from the load; available renewable resources; impact on voltage profile, fault contribution, thermal loading of the equipment and power loss. The results from both case studies show that the impact of DG on the voltage profile is negligible. The greatest impact on voltage profile was found to be at the site closest to the load. Asynchronous and synchronous generators have a greater fault contribution than inverter-based DG. The fault contribution is proportional to the distance from the load. Overall, thermal loading of lines increased marginally, but decreased based on distances from the load. Power loss on short lines is negligible but there is a significant loss on the line between the load and DG based on the distance from the load. Electricity generated from wind power is the most viable based on LCOE and NPC. For larger wind systems, as illustrated by the second case study, grid parity has already been reached. Wheeling of wind energy has already proven to be an economically viable option. According to future cost projection, large scale solar energy will become viable by 2019. The concept of wheeling energy between an IPP and off-taker has technical and economic merit. Wheeling charges are perceived to be high, but this is not the case as wheeling tariffs consist of standard network charges. In the future, renewable energy will continue to mature based on technology and cost. Solar energy, including lithium-ion battery back-up technology, looks promising based on future cost projections. Deregulation of the electricity market holds the key to the successful implementation of energy wheeling as it will open the market up for greater competition.
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Calvin, Christophe. "Minimisation du sur-coût des communications dans la parallélisation des algorithmes numériques." Phd thesis, Grenoble INPG, 1995. http://tel.archives-ouvertes.fr/tel-00005034.
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Le but de ce memoire est d'étudier les voies possibles pour minimiser le sur-coût des communications consécutif à la parallélisation d'algorithmes numériques sur machines parallèles à mémoire distribuée. La première voie explorée consiste à optimiser les schémas de communication des données et résultats mis en oeuvre dans les versions parallèles de noyaux de calcul. Nous proposons notamment de nouveaux algorithmes pour réaliser une transposition de matrices carrées allouées par blocs, sur différentes topologies de réseaux d'interconnexion. Nous avons également étudié le problème de l'échange total. Ce schéma de communication se retrouve fréquemment dans les versions parallèles d'algorithmes numériques (comme dans l'algorithme du gradient conjugué). Nous proposons des algorithmes efficaces d'échange total pour des topologies toriques. La deuxième voie qui a été explorée consiste à recouvrir les communications par du calcul. Nous avons étudié quelques principes algorithmiques de base permettant de masquer au mieux les communications. Ceux-ci sont basés, notamment, sur des techniques d'enchainement de phases de calcul et de communication, ainsi que sur le re-ordonnancement local de tâches afin d'optimiser le recouvrement. Ces techniques sont illustrées sur des algorithmes parallèles de calcul de transformée de Fourier. Les différentes implantations de ces algorithmes sur de nombreuses machines parallèles à mémoire distribuée (T3D de Cray, SP2 d'IBM, iPSC-860 et Paragon d'Intel) montrent le gain en temps d'exécution apporté par ces méthodes.
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Barton, John P. "A probabilistic method of modelling energy storage in electricity systems with intermittent renewable energy." Thesis, Loughborough University, 2007. https://dspace.lboro.ac.uk/2134/9727.
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A novel probabilistic method has been developed for modelling the operation of energy storage in electricity systems with significant amounts of wind and solar powered generation. This method is based on a spectral analysis of the variations of wind speed and solar irradiance together with profiles of electrical demand. The method has been embodied in two Matlab computer programs: Wind power only: This program models wind power on any time scale from seconds to years, with limited modelling of demand profiles. This program is only capable of modelling stand-alone systems, or systems in which the electrical demand is replaced by a weak grid connection with limited export capacity. 24-hours: This program models wind power, solar PV power and electrical demand, including seasonal and diurnal effects of each. However, this program only models store cycle times (variations within a time scale) of 24 hours. This program is capable of modelling local electrical demand at the same time as a grid connection with import or export capacity and a backup generator. Each of these programs has been validated by comparing its results with those from a time step program, making four Matlab programs in total. All four programs calculate the power flows to and from the store, satisfied demand, unsatisfied demand and curtailed power. The programs also predict the fractions of time that the store spends full, empty, filling or emptying. The results obtained are promising. Probabilistic program results agree well with time step results over a wide range of input data and time scales. The probabilistic method needs further refinement, but can be used to perform initial modelling and feasibility studies for renewable energy systems. The probabilistic method has the advantage that the required input data is less, and the computer run time is reduced, compared to the time step method.
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Wang, Yuanzhe, and 王远哲. "Macromodeling, passivity enforcement and fast simulation/verification for interconnects, power grids and large circuits." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46604376.
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Joshi, Ajay Jayant. "Wave-Pipelined Multiplexed (WPM) Routing for Gigascale Integration (GSI)." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10549.
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The main objective of this research is to develop a pervasive wire sharing technique that can be easily applied across the entire range of on-chip interconnects in a very large scale integration (VLSI) system. A wave-pipelined multiplexed (WPM) routing technique that can be applied both intra-macrocell and inter-macrocell interconnects is proposed in this thesis. It is shown that an extensive application of the WPM routing technique can provide significant advantages in terms of area, power and performance. In order to study the WPM routing technique, a hierarchical approach is adopted. A circuit-level, system-level and physical-level analysis is completed to explore the limits and opportunities to apply WPM routing to current VLSI and future gigascale integration (GSI) systems. Design, verification and optimization of the WPM circuit and measurement of its tolerance to external noise constitute the circuit-level analysis. The physical-level study involves designing wire sharing-aware placement algorithms to maximize the advantages of WPM routing. A system-level simulator that designs the entire multilevel interconnect network is developed to perform the system-level analysis. The effect of WPM routing on a full-custom interconnect network and a semi-custom interconnect network is studied.
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Paquette, Andrew Donald. "Power quality and inverter-generator interactions in microgrids." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51803.
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This research addresses some of the difficulties faced when operating voltage controlled inverters with synchronous generators in microgrids. First, an overview of microgrid value propositions is provided, and the problems faced when attempting to use microgrids to provide improved power quality are discussed. Design considerations for different types of microgrids are provided to enable microgrids to deliver the desired functionality without adding unnecessary cost. The main body of this research investigates the poor transient load sharing encountered between voltage controlled inverters and synchronous generators in islanded operation. Poor transient load sharing results in high peak inverter rating requirements and high cost. The tradeoff between power quality and power sharing is highlighted, and methods to improve transient load sharing are proposed. The use of current limiting to protect inverters during faults and overloads is also investigated. Stability problems are identified when using simple inverter current limiting methods when operating in parallel with synchronous generators. Virtual impedance current limiting is proposed to improve transient stability during current limiting. The methods proposed in this thesis for mitigating inverter overloads and faults will allow for more reliable and cost effective application of inverter based distributed energy resources with synchronous generators in microgrids.
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Bhatnagar, Rahul. "Dynamic dispatch of direct load control." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54736.
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Direct Load Control (DLC) -- the direct control of customer loads by an electric utility for the economic and reliable operation of the power system, is an important and active element of Load Management (LM). Currently attention has focussed on the integration of DLC into system operations. However, as yet, DLC is regarded as a discretionary resource to be used by the system operator based on informed judgment. The integration process has therefore, concentrated on improving the informational inputs to the operator.
This dissertation extends the integration from that of a discretionary resource to a dispatchable system resource. The concept of the dynamic dispatch of DLC is formulated and defined to be an online evaluation and utilization of DLC for optimum benefit to the utility, as system conditions change. The concept envisages the use of DLC in an automated mode and coordinated with other system resources for optimum benefit.
An important and integral part of the research effort is the development of a cost characterization of DLC. A closed form solution, using a dynamic programming framework, has been developed to estimate the costs of DLC dispatch. The derivation takes into account all operational constraints on the utilization of DLC -- payback characteristics, maximum on-times and minimum recovery times. The cost, defined as the difference in the fuel costs with and without DLC dispatch, were found to be dependent on the cost characteristics of the online generators and the load shape impacts of DLC dispatch.
The dynamic dispatch concept is concretized by a power system operations model which incorporates DLC dispatch for fuel cost minimization and peak load shaving. The two modes are toggled by the dispatch algorithm as system conditions change. Results from the model are presented for several combinations of system conditions and DLC system parameters.Ph. D.
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Brown, Nathan L. "An evaluation of transfer capability limitations and solutions for South Mississippi Electric Power Association." Master's thesis, Mississippi State : Mississippi State University, 2002. http://library.msstate.edu/etd/show.asp?etd=etd-03252002-094046.
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Bharath, Krishna. "Signal and power integrity co-simulation using the multi-layer finite difference method." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28155.
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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.Committee Chair: Madhavan Swaminathan; Committee Member: Andrew F. Peterson; Committee Member: David C. Keezer; Committee Member: Saibal Mukhopadyay; Committee Member: Suresh Sitaraman.
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Mallem, Badis. "Modélisation, analyse et commande des grands systèmes électriques interconnectés." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2010. http://tel.archives-ouvertes.fr/tel-00557829.
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Cette thèse porte sur la modélisation, la réduction et la commande des grands systèmes électriques.En terme de modélisation et de réduction, l'objectif principal est de développer une méthode de réduction des modèles dynamiques des systèmes électriques. Cette réduction a pour objet de répondre à une situation particulière dans laquelle toutes les données du système à réduire ne sont pas connues.En terme de commande, l'objectif est la conception de commandes robustes coordonnées pour répondre aux nouvelles contraintes des grands systèmes électriques. Ces approches doivent respecter trois niveaux de coordination et deux nouvelles contraintes. Les trois niveaux de coordination concernent la prise en compte simultanée des oscillations électromécaniques interzones et locaux, la coordination de la synthèse de régulateurs pour plusieurs alternateurs, et la coordination du réglage des paramètres (gains et constantes de temps) des régulateurs de tension (les boucles stabilisatrices PSS) avec le réglage des paramètres des régulateurs de turbine des alternateurs. Les contraintes sont liées à la stabilité et la robustesse des régulateurs proposés.
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Snyder, Aaron Francis. "Les mesures synchronisées par GPS pour l'amortissement des oscillations de puissance dans les grands réseaux électriques interconnectés." Phd thesis, Grenoble INPG, 1999. http://tel.archives-ouvertes.fr/tel-00784966.
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Les grands réseaux électriques sont utilisés de plus en plus près de leur limite de stabilité Ceci est dû aux contraintes économiques, politiques et écologiques obligent tes opérateurs1 à exploiter leurs réseaux à la limite de sécurité. Cependant faire fonctionner un réseau trop près de ses limites crée des oscillations de puissance entre les différentes centrales et parties des réseaux liées par des interconnexions assez faibles (en, terme de nombre de lignes d'interconnexion). Ces oscillations " inter-régions " se manifestent sur les arbres des machines concernées (oscillations électro-mécaniques) et affectent la stabilité du réseau. Un moyen efficace pour remédier à ce problème consiste en une utilisation d'un correcteur dit RFC (Remote Feedback Controller). Ce correcteur utilise comme signaux d'entrée des grandeurs provenant de machines distantes du point d'installation du correcteur Ces signaux sont synchronisés par des satellites GPS (Global Positioning System). Les outils d'analyse et de calcul comme l'optimisation convexe avec contraintes LMI (inégalités matricielles linéaires), peuvent permettre le réglage de ce correcteur. Dans te cadre de cette thèse, le travail réalisé traite du problème de la conception et de l'emplacement d'un correcteur RFC utilisant des signaux d'entrée locaux et lointains synchronisés. par les satellites GPS. Les. techniques de programmation convexe avec des contraintes LMÏ sont utilisées pour le réglage de ce correcteur pour l'amortissement des oscillations inter-régions dans lés réseaux électriques. Les correcteurs réalisés sont ensuite implantés dans deux réseaux tests à 4 à 29 machines. Grâce aux techniques LMI les correcteurs sont robustes dans une grande plage de points de fonctionnement des réseaux tests et sont plus performants que les correcteurs traditionnels. De plus, ces correcteurs ne sont pas perturbés par d'éventuels problèmes dus à l'éloignement des signaux, notamment par un retard du signal ou par sa perte éventuelle.
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Reehal, Gursharan Kaur. "Designing Low Power and High Performance Network-on-Chip Communication Architectures for Nanometer SoCs." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1340022240.
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Gumede, Nkosinomusa S. "Eskom-ZESA interconnected power system modelling." Thesis, 2016. http://hdl.handle.net/10539/21110.
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A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering, 2016The power system frequency must be kept as close as possible to the nominal value. This is due to the inherent design of electrical equipment to operate efficiently at the nominal frequency. Frequency regulation in an interconnected power system is the duty of all members of the interconnection. However, in the Eskom-ZESA interconnected power system Eskom engineers ignore the contribution of the ZESA system to primary frequency control. This is mainly due to the prevalent assumption that the ZESA control area is small relative to the Eskom control area and its contribution to primary frequency control of the interconnected power system is negligible. This document presents a project that examines the validity of this assumption via determination of the contribution of the ZESA system to the interconnected power system’s primary frequency control. The interconnected power systems background was studied to understand the theory behind the operation of two or more interconnected power systems. System frequency disturbances deemed to be a good representation of the Eskom-ZESA interconnected power system’s performance were selected and analysed to validate the current assumption. The results show that there is a significant support from ZESA during a system frequency disturbance. This proves that the existing assumption is not valid anymore. Furthermore; the generator model that mimics the Eskom-ZESA tie-line governing behaviour was developed. Two different types of governor models were employed; firstly the IEEEG1 governor was tuned to control generator output to match the tie-line performance and then the TGOV5 governor model was used. The IEEEG1 governor model is a simplified governor representation; as a result, it is not easy to tune the parameters to match tie-line response. However, the performance is acceptable and it can be used to represent the tieline governor response. The TGOV5 governor model is very complex as discussed in section 4.2. The model includes boiler dynamics, and this improves performance such that it is possible to tune the parameters to follow the tie-line performance as close as necessary.
GR2016
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Ajit, Kumar *. "Design Of Robust Power System Damping Controllers For Interconnected Power Systems." Thesis, 2010. http://etd.iisc.ernet.in/handle/2005/1653.
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Small signal oscillation has been always a major concern in the operation of power systems. In a generator, the electromechanical coupling between the rotor and the rest of the system causes it to behave in a manner similar to a spring mass damper system, which exhibits an oscillatory behaviour around the equilibrium state, following any disturbance, such as sudden change in loads, fluctuations in the output of turbine and faults etc. The use of fast acting high gain AVRs and evolution of large interconnected power systems with transfer of bulk power across weak transmission links have further aggravated the problem of these low frequency oscillations. Small oscillations in the range of about 0.1Hz to 3.5Hz can persist for long periods, limiting the power transfer capability of the transmission lines. Power System Stabilizers (PSS’s) were developed as auxiliary controllers on the generators excitation system to produce additional damping by modulating the generator excitation voltage. Designing effective PSS for all operating conditions specially in large interconnected power systems still remains a difficult and challenging task.
The conventionally designed Power System Stabilizer (CPSS) is the most cost-effective electromechanical damping controller till date. However, continual changes in the operating condition and network parameters in large systems result in corresponding large changes in system dynamics. This constantly changing nature of power system makes the design of CPSS a difficult task. The design and tuning of PSS for robust operation is a laborious process. The existing PSS design techniques require considerable expertise, the complete system information and extensive eigenvalue calculations which increases the computational burden as the system size increases.
This thesis proposes a method for designing robust power system damping controllers that ensures a minimum robustness under model uncertainties. The minimum performance required for the PSS is set a priori and accomplished over a range of operating conditions.
A generalized robust controller design methodology has been first implemented on a Single Machine Infinite Bus (SMIB) power system model. The robust controller places the closed loop rotor modes of the system to the desire location while keeping the electrical modes intact. Unlike conventional lead/lag PSS design, the proposed PSS design is based on pole assignment technique which takes into account of various model uncertainties.
For the proposed stabilizer design in a multi-machine systems a new decentralized method has been used which requires system data only upto secondary bus of the unit transformer in a generating station. The proposed robust controller design based on modified Nevanlinna-Pick theory has been designed and tested extensively on SMIB and multi-machine systems to establish the efficacy of the controller in damping small signal oscillations.
The thesis is organized in four chapters as follows.
The first chapter discusses the basic concepts related to the rotor angle stability in power system. The conventional and other methods of countering this instability by power system stabilizers have been described. The relative merits of the various stabilization techniques have been discussed. The scope of present work, i.e design of decentralized robust power system controllers has been defined.
In second chapter a modified robust power system stabilizer for SMIB system is developed. It has been shown that under specific conditions the modified Nevanlinna-Pick theory can also be applied for designing damping controllers in system with lightly damped rotor modes.
Third chapter proposes a decentralized approach based on modified Nevanlinna-Pick theory for designing a power system stabilizer for interconnected power systems. The performance of the controller which is not based on external system information has been investigated on three widely used multi-machine test systems to established its efficacy in damping out low frequency oscillations.
The fourth chapter gives a brief summary of the work done and also includes a section on the scope of future work relating to design of power system stabilizers.
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Hsia, Lei, and 夏磊. "Research of AGC Control in Interconnected Power System." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/xbb83p.
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碩士國立臺灣大學
電機工程學研究所
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The power system frequency is one of the three performance indicators of the power system operating quality. Frequency stability is the basic requirement for the operation of the power system. The premise is that the power generation and load including the power loss of the network match each other. According to the load changes of the power system, how to adjust the output of the generator at any time to meet the requirements of the load changes is a problem solved by the automatic generation control. The interconnected power system has time-varying, nonlinear, large delay, uncertainty and other characteristics. The conventional PID controller can not achieve excellent control performance. In order to improve the control performance of the complex system, this thesis designs the adaptive PID controller based on fuzzy control. Comparing with the conventional PID controller, the simulation results show that: in the interconnected power system, the adaptive PID controller based on fuzzy control improves the dynamic and static characteristics of the system. Afterwards, we use the particle swarm optimization algorithm to obtain the best value of the PID control parameters. Through observing the dynamic response conditions such as the frequency of the two regions and the change of the exchange power of the connection lines, we can prove the feasibility and superiority of the method.