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Machuca, Julían, und Thomas Tuvesson. „PCB design of Power Distributor Unit (PDU)“. Thesis, Uppsala universitet, Institutionen för elektroteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-415474.
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The project idea was created from the demand of a renewal for a Power Distributor Unit also known as a PDU. The current product had successively turned in to a cable mess because of short term solutions. This made the product non user friendly, inconvenient and non-agile to handle troubleshooting. To develop this project, a PCB design was created by simplifying and improving circuit diagrams until satisfied. Once the final circuit diagram was obtained, a PCB layout design was created. The result of the project, due to limited time, was only theoretical. The finished product was not tested as there was no time allowing this.
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Jain, Sheetal A. 1980. „Low-power single-precision IEEE Floating-point unit“. Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/87426.
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Zhuang, Fulin 1956. „Optimal generation unit commitment in thermal electric power systems“. Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75896.
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This thesis is devoted to the optimal commitment of generation units in an all-thermal, single or multiple area, power system. The problem, known as unit commitment, is a nonlinear mixed program typically with thousands of 0-1 integer variables and diverse constraints. An exact optimal solution to the problem is only possible via (explicit or implicit) enumeration, which requires a prohibitively long computation time for large problem instances.Two optimization approaches, Lagrangian relaxation and simulated annealing, are explored in this thesis for efficient and near-optimal unit commitment.
Lagrangian relaxation combines the solution of the dual of the unit commitment problem with feasibility search to obtain primal feasible solutions. The feasibility search is necessary because a solution to the dual seldom solves the primal, and because little theory is available to bridge the optimal dual and primal solutions. In this thesis, several new feasibility search procedures to find a near-optimal primal feasible solution from the dual solution are developed and tested. These procedures are independent of the data constituting different problem instances, and are more rigorous and systematic than the existing ones. With these procedures, Lagrangian relaxation is successfully and efficiently applied to both single and multiple area unit commitment.
Simulated annealing exploits the resemblance between a minimization process and the cooling of a molten metal. The method generates feasible solution points randomly and moves among these points following a strategy which leads to a global minimum in a statistical sense. Simulated annealing is very flexible for handling diverse and complicated constraints, such as those typical of the unit commitment problem. Simulated annealing is analyzed, evaluated and implemented for unit commitment in this thesis.
Five major algorithms, proposed in this thesis for unit commitment and reserve-constrained economic dispatch, are extensively tested and compared by numerical simulation on sample power systems of 10 to 100 units. The simulation results show the efficiency of the tested algorithms for large-scale unit commitment and demonstrate the general applicability of simulated annealing. A comparison with the priority list method and a study of the convergence rates of the subgradient type algorithms are also included in the simulation.
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Kandil, Nahi A. „Unit Response Modeling and Forecasting for a Large Electric Power System“. Ohio University / OhioLINK, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1239730577.
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Rahmqvist, Elin. „On stochastic unit commitment for thermal power plants“. Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-285519.
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Climate change is a fact, a crisis threatening every country, economy and human. Toprevent this crisis, the emission of greenhouse gases needs to decrease dramatically. 72%of global greenhouse gas emissions in 2016 came from energy production where electricityand heat account for 42% of the 72%. Nevertheless, coal power grew with 28% in2018 to meet the increased demand of electricity. It is therefore of utmost importancethat the resources used in power plants are distributed as efficiently as possible. Unitcommitment is a short-term planning formulation which is part of the planning chain forproduction of electrical energy. An accurate unit commitment can decrease emissionsand costs.The aim of this study is to implement a model for the stochastic behavior of the electricalload into unit commitment. With this, it shall be evaluated, whether this solutionis robust enough for usage in network control. The evaluation needs to assess the reliability,economic impact and the computational e↵ort for solving the stochastic unitcommitment problem.A test system has been created in MATLAB to evaluate the stochastic versus deterministicunit commitment formulation. Scenarios for the stochastic unit commitmenthave been generated by using a stationary, discrete-time Markov Chain to generate loadforecast errors. The Fast Forward Selection method has been used to reduce number ofscenarios to minimize computational e↵ort. The quality of the solution has then beenevaluated with value of the stochastic solution for economic analysis. Loss of load probabilityand energy not served have been used to evaluate the reliability.A stochastic approach gives a more robust solution but can be more expensive in termsof costs. Five scenarios were the optimal choice for the stochastic unit commitmentformulation. Increasing number of scenarios did not improve the reliability and resultedin a more expensive solution. The conclusion of this work can be contradictory but highlightsone of the challenges in electric power systems. A more robust system is usuallymore costly and therefore the players in the system must decide what is most desirablein this particular system. A more reliable but expensive system or a less reliable andless costly system.Klimatförändringarna är ett faktum, en kris som hotar varje land, ekonomi och människa.För att förebygga denna kris måste utsläppen av växthusgaser minska dramatiskt. 72 % av de globala utsläppen av växthusgaser år 2016 kom från energiproduktion där värme och elektricitet stod för 42 % av dessa utsläpp. Trots detta växte kolkraften med 28% år 2018 för att kunna möta den ökande efterfrågan på elektricitet. Det är därför av yttersta vikt att dessa resurser används på ett så e↵ektivt sätt som möjligt. En bra och exakt korttidsplanering av kraftsystem kan minska utsläppen och kostnaderna.Målet med denna studie är att implementera stokastisk last i korttidsplaneringen för ett mindre elkraftsystem med 11 enheter. Detta kräver en robust metod som begränsar beräkningstiden för att säkerställa kontinuerlig och säker drift av elkraftsystemet. Analysen måste utvärdera tillförlitligheten, ekonomiska e↵ekterna och beräkningstiden för att lösa det stokastiska korttidsplaneringsproblemet.Ett testsystem har skapats i MATLAB för att utvärdera den stokastiska kontra deterministiska korttidsplaneringsproblemet. Scenarier för det stokastiska korttidsplaneringen har genererats genom att använda en stationär Markov-kedja för att generera felen i lastprognosen och sedan använda Fast Forward Selection metoden för att minska antalet scenarier för att minimera beräkningsinsatsen. Stokastisk korttidsplanering har sedan utvärderats med värdet av den stokastiska lösningen för ekonomisk analys. Sannolikheten för bortkoppling av last samt icke levererad energi har beräknats för att utvärdera tillförlitligheten.En stokastisk metod ger en mer robust lösning men kan vara dyrare vad gäller kostnader. Fem scenarier var det optimala valet för den stokastiska korttidsplaneringsformuleringen. Ö kande av antal scenarier förbättrade inte tillförlitligheten och resulterade i en dyrare lösning. Slutsatsen i detta arbete kan kännas motsägelsefullt då den deterministiska metoden visar på lägre kostnader medans den stokastiska är mer robust. Detta belyser en av utmaningarna i elkraftsystem. Ett mer robust system är vanligtvis dyrare och därför måste aktörerna i systemet bestämma vad som är mest önskvärt i det specifika systemet. Ett mer tillförlitligt men dyrare system eller ett mindre pålitligt och billigaresystem.
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Restrepo, Jose Fernando. „Unit commitment with primary frequency regulation constraints in electric power systems“. Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18210.
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The unit commitment problem with secondary and tertiary reserve requirements with time constants ranging from two to thirty minutes has been broadly studied in electric power systems. In contrast, the scheduling of units offering primary frequency regulation reserve deployable within seconds of a contingency has received relatively little attention. In this dissertation we formulate and solve a unit commitment problem explicitly accounting for the characteristic that primary frequency regulation has a single common degree of freedom, namely, the system frequency deviation. The simultaneous scheduling of energy, primary and tertiary reserves is then studied through a number of cases of up to 34 generating units.Le problème de la planification de l’opération des unités de production d’électricité comprenant des spécifications des niveaux de régulation secondaire et tertiaire (celles-ci agissant sur un horizon de temps compris entre deux et trente minutes) a été amplement étudié. Le problème de planification de la production comprenant les aspects relatifs à la régulation primaire, agissant en fonction des variations de fréquence du réseau dans un horizon de temps de quelques secondes, n’a cependant reçu que peu d’attention jusqu’à maintenant. Dans ce mémoire, nous développons et solutionnons le problème de la planification de la production d’électricité en incluant la notion de la régulation primaire. On démontre que celle-ci est gouvernée explicitement et uniquement par la variation de la fréquence du réseau. Ensuite, la planification simultanée de la production d’énergie et de la fourniture des services de régulation primaire et tertiaire est étudiée via des études de cas sur des systèmes types possédant jusqu’à 34 unités de production.
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Ofori-Tenkorang, John. „A microprocessor-controlled household power monitoring unit by John Ofori-Tenkorang“. Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/14288.
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Uong, Hoang. „The application of the ordered list method and the dynamic programming to the unit commitment“. PDXScholar, 1989. https://pdxscholar.library.pdx.edu/open_access_etds/3948.
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Wu, Zhi. „Transmission expansion planning and unit commitment with large-scale integration of wind power“. Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6738/.
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The large-scale integration of wind generation into the power system brings great challenges to transmission expansion planning (TEP) and unit commitment (UC). The intermittence nature of wind generation needs to be fully considered in these two problems, which stimulates the research of this thesis. The selection of candidate lines is the prerequisite for the TEP problem. Considering the limitations of manual selection approach, a method to select candidate lines automatically is proposed, which consists of five stages to reinforce existing corridors and new corridors. Results of the two test systems illustrate that the locational marginal price difference is neither sufficient nor necessary condition for candidate lines. The uncertainty of load demand and wind power is studied both in the TEP and UC problems. In the term of TEP, a two-stage stochastic formulation of TEP is proposed. The stochastic dual dynamic programming (SDDP) approach is applied to consider the uncertainty, and the whole model is solved by Benders decomposition (BD) technique. In the term of UC, the chance-constrained two-stage programming formulation is proposed for the day-ahead UC problem. The chance-constrained stochastic programming formulation is converted into an equivalent deterministic formulation by a sequence of approximation and verification.
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Ghassempour, Aghamolki Hossein. „Phasor Measurement Unit Data-based States and Parameters Estimation in Power System“. Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6505.
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The dissertation research investigates estimating of power system static and dynamic states (e.g. rotor angle, rotor speed, mechanical power, voltage magnitude, voltage phase angle, mechanical reference point) as well as identification of synchronous generator parameters. The research has two focuses:
i. Synchronous generator dynamic model states and parameters estimation using real-time PMU data.
ii.Integrate PMU data and conventional measurements to carry out static state estimation.
The first part of the work focuses on Phasor Measurement Unit (PMU) data-based synchronous generator states and parameters estimation. In completed work, PMU data-based synchronous generator model identification is carried out using Unscented Kalman Filter (UKF). The identification not only gives the states and parameters related to a synchronous generator swing dynamics but also gives the states and parameters related to turbine-governor and primary and secondary frequency control. PMU measurements of active power and voltage magnitude, are treated as the inputs to the system while voltage phasor angle, reactive power, and frequency measurements are treated as the outputs. UKF-based estimation can be carried out at real-time. Validation is achieved through event play back to compare the outputs of the simplified simulation model and the PMU measurements, given the same input data. Case studies are conducted not only for measurements collected from a simulation model, but also for a set of real-world PMU data. The research results have been disseminated in one published article.
In the second part of the research, new state estimation algorithm is designed for static state estimation. The algorithm contains a new solving strategy together with simultaneous bad data detection. The primary challenge in state estimation solvers relates to the inherent non-linearity and non-convexity of measurement functions which requires using of Interior Point algorithm with no guarantee for a global optimum solution and higher computational time. Such inherent non-linearity and non-convexity of measurement functions come from the nature of power flow equations in power systems.
The second major challenge in static state estimation relates to the bad data detection algorithm. In traditional algorithms, Largest Normalized Residue Test (LNRT) has been used to identify bad data in static state estimation. Traditional bad data detection algorithm only can be applied to state estimation. Therefore, in a case of finding any bad datum, the SE algorithm have to rerun again with eliminating found bad data. Therefore, new simultaneous and robust algorithm is designed for static state estimation and bad data identification.
In the second part of the research, Second Order Cone Programming (SOCP) is used to improve solving technique for power system state estimator. However, the non-convex feasible constraints in SOCP based estimator forces the use of local solver such as IPM (interior point method) with no guarantee for quality answers. Therefore, cycle based SOCP relaxation is applied to the state estimator and a least square estimation (LSE) based method is implemented to generate positive semi-definite programming (SDP) cuts. With this approach, we are able to strengthen the state estimator (SE) with SOCP relaxation. Since SDP relaxation leads the power flow problem to the solution of higher quality, adding SDP cuts to the SOCP relaxation makes Problem’s feasible region close to the SDP feasible region while saving us from computational difficulty associated with SDP solvers. The improved solver is effective to reduce the feasible region and get rid of unwanted solutions violate cycle constraints. Different Case studies are carried out to demonstrate the effectiveness and robustness of the method.
After introducing the new solving technique, a novel co-optimization algorithm for simultaneous nonlinear state estimation and bad data detection is introduced in this dissertation. ${\ell}_1$-Norm optimization of the sparse residuals is used as a constraint for the state estimation problem to make the co-optimization algorithm possible. Numerical case studies demonstrate more accurate results in SOCP relaxed state estimation, successful implementation of the algorithm for the simultaneous state estimation and bad data detection, and better state estimation recovery against single and multiple Gaussian bad data compare to the traditional LNRT algorithm.
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Hassan, Mohamed Elhafiz. „Power Plant Operation Optimization : Unit Commitment of Combined Cycle Power Plants Using Machine Learning and MILP“. Thesis, mohamed-ahmed@siemens.com, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-395304.
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In modern days electric power systems, the penetration of renewable resources and the introduction of free market principles have led to new challenges facing the power producers and regulators. Renewable production is intermittent which leads to fluctuations in the grid and requires more control for regulators, and the free market principle raises the challenge for power plant producers to operate their plants in the most profitable way given the fluctuating prices. Those problems are addressed in the literature as the Economic Dispatch, and they have been discussed from both regulator and producer view points. Combined Cycle Power plants have the privileges of being dispatchable very fast and with low cost which put them as a primary solution to power disturbance in grid, this fast dispatch-ability also allows them to exploit price changes very efficiently to maximize their profit, and this sheds the light on the importance of prices forecasting as an input for the profit optimization of power plants. In this project, an integrated solution is introduced to optimize the dispatch of combined cycle power plants that are bidding for electricity markets, the solution is composed of two models, the forecasting model and the optimization model. The forecasting model is flexible enough to forecast electricity and fuel prices for different markets and with different forecasting horizons. Machine learning algorithms were used to build and validate the model, and data from different countries were used to test the model. The optimization model incorporates the forecasting model outputs as inputs parameters, and uses other parameters and constraints from the operating conditions of the power plant as well as the market in which the plant is selling. The power plant in this mode is assumed to satisfy different demands, each of these demands have corresponding electricity price and cost of energy not served. The model decides which units to be dispatched at each time stamp to give out the maximum profit given all these constraints, it also decides whether to satisfy all the demands or not producing part of each of them.
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Ghanavati, Goodarz. „Statistical Analysis of High Sample Rate Time-series Data for Power System Stability Assessment“. ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/333.
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The motivation for this research is to leverage the increasing deployment of the phasor measurement unit (PMU) technology by electric utilities in order to improve situational awareness in power systems. PMUs provide unprecedentedly fast and synchronized voltage and current measurements across the system. Analyzing the big data provided by PMUs may prove helpful in reducing the risk of blackouts, such as the Northeast blackout in August 2003, which have resulted in huge costs in past decades.
In order to provide deeper insight into early warning signs (EWS) of catastrophic events in power systems, this dissertation studies changes in statistical properties of high-resolution measurements as a power system approaches a critical transition. The EWS under study are increases in variance and autocorrelation of state variables, which are generic signs of a phenomenon known as critical slowing down (CSD).
Critical slowing down is the result of slower recovery of a dynamical system from perturbations when the system approaches a critical transition. CSD has been observed in many stochastic nonlinear dynamical systems such as ecosystem, human body and power system. Although CSD signs can be useful as indicators of proximity to critical transitions, their characteristics vary for different systems and different variables within a system.
The dissertation provides evidence for the occurrence of CSD in power systems using a comprehensive analytical and numerical study of this phenomenon in several power system test cases. Together, the results show that it is possible extract information regarding not only the proximity of a power system to critical transitions but also the location of the stress in the system from autocorrelation and variance of measurements. Also, a semi-analytical method for fast computation of expected variance and autocorrelation of state variables in large power systems is presented, which allows one to quickly identify locations and variables that are reliable indicators of proximity to instability.
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Garcia, Arregui Marcos Astier Stéphan Turpin Christophe. „Theoretical study of a power generation unit based on the hybridization of a fuel cell stack and ultracapacitors application to the design of an aircraft emergency electrical network /“. Toulouse : INP Toulouse, 2008. http://ethesis.inp-toulouse.fr/archive/00000521.
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Garcia, Arregui Marcos. „Theoretical study of a power generation unit based on the hybridization of a fuel cell stack and ultracapacitors : application to the design of an aircraft emergency electrical network“. Toulouse, INPT, 2007. http://ethesis.inp-toulouse.fr/archive/00000521/.
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Le travail présenté dans ce mémoire porte sur la conception d'un réseau électrique à base d'une pile à combustible et son organe de stockage associé. Le contexte de ce travail se place dans une application aéronautique. Les piles à combustible à air comprimé ont besoin de certains dispositifs auxiliaires qui permettent la bonne diffusion des gaz. A cause de ces dispositifs auxiliaires, la dynamique globale du système est limitée, et une hybridation avec une source de puissance auxiliaire peut être nécessaire. En outre, l'hybridation a un impact positif sur la taille du système, et peut mener à la réduction du poids et du volume du système global. Les supercapacités semblent bien adaptées pour cette mission. Étant donné que notre système est dédié à une application embarquée, le volume, le poids, le coût ainsi que la consommation d'hydrogène sont des paramètres clés pour le choix de l’une des architectures proposées. Donc, une optimisation globale du système semble nécessaireThe presented work deals with the design and conception of an electrical network from a fuel cell stack and its associated storage device. The framework of this project is an aeronautical and transport application. Air pressurized fuel cell stacks need some auxiliary devices that permits a correct gas flow through the fuel cell stack. Due to the auxiliary devices, the fuel cell dynamics performances may be limited, and a power buffer is required to support power peaks. Furthermore, hybridization has a positive effect in the system size, and can lead to reduce the global system weight and volume. Ultracapacitos seem to be well adequate for this purpose. Due to the transport application, the system hydrogen consumption, volume, weight and cost are essential parameters. Due to the transport application, the system hydrogen consumption, volume, weight and cost are sizing essential parameters. Therefore a global system optimization seems mandatory in this cas
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Hurtgen, Michaël. „Wide-area state estimation using synchronized phasor measurement units“. Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209924.
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State estimation is an important tool for power system monitoring and the present study involves integrating phasor measurement units in the state estimation process. Based on measurements taken throughout the network, the role of a state estimator is to estimate the state variables of the power system while checking that these estimates are consistent with the measurement set. In the case of power system state estimation, the state variables are the voltage phasors at each network bus.\\The classical state estimator currently used is based on SCADA (Supervisory Control and Data Acquisition) measurements. Weaknesses of the SCADA measurement system are the asynchronicity of the measurements, which introduce errors in the state estimation results during dynamic events on the electrical network.\\
Wide-area monitoring systems, consisting of a network of Phasor Measurement Units (PMU) provide synchronized phasor measurements, which give an accurate snapshot of the monitored part of the network at a given time. The objective of this thesis is to integrate PMU measurements in the state estimator. The proposed state estimators use PMU measurements exclusively, or both classical and PMU measurements.\\
State estimation is particularly useful to filter out measurement noise, detect and eliminate bad data. A sensitivity analysis to measurement errors is carried out for a state estimator using only PMU measurements and a classical state estimator. Measurement errors considered are Gaussian noise, systematic errors and asynchronicity errors. Constraints such as zero injection buses are also integrated in the state estimator. Bad data detection and elimination can be done before the state estimation, as in pre-estimation methods, or after, as in post-estimation methods. For pre-estimation methods, consistency tests are used. Another proposed method is validation of classical measurements by PMU measurements. Post-estimation is applied to a measurement set which has asynchronicity errors. Detection of a systematic error on one measurement in the presence of Gaussian noise is also analysed. \\
The state estimation problem can only be solved if the measurements are well distributed over the network and make the network observable. Observability is crucial when trying to solve the state estimation problem. A PMU placement method based on metaheuristics is proposed and compared to an integer programming method. The PMU placement depends on the chosen objective. A given PMU placement can provide full observability or redundancy. The PMU configuration can also take into account the zero injection nodes which further reduce the number of PMUs needed to observe the network. Finally, a method is proposed to determine the order of the PMU placement to gradually extend the observable island. \\
State estimation errors can be caused by erroneous line parameter or bad calibration of the measurement transformers. The problem in both cases is to filter out the measurement noise when estimating the line parameters or calibration coefficients and state variables. The proposed method uses many measurement samples which are all integrated in an augmented state estimator which estimates the voltage phasors and the additional parameters or calibration coefficients.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Mazloomzadeh, Ali. „Development of Hardware in the Loop Real-Time Control Techniques for Hybrid Power Systems Involving Distributed Demands and Sustainable Energy Sources“. FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1666.
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The future power grid will effectively utilize renewable energy resources and distributed generation to respond to energy demand while incorporating information technology and communication infrastructure for their optimum operation. This dissertation contributes to the development of real-time techniques, for wide-area monitoring and secure real-time control and operation of hybrid power systems.
To handle the increased level of real-time data exchange, this dissertation develops a supervisory control and data acquisition (SCADA) system that is equipped with a state estimation scheme from the real-time data. This system is verified on a specially developed laboratory-based test bed facility, as a hardware and software platform, to emulate the actual scenarios of a real hybrid power system with the highest level of similarities and capabilities to practical utility systems. It includes phasor measurements at hundreds of measurement points on the system. These measurements were obtained from especially developed laboratory based Phasor Measurement Unit (PMU) that is utilized in addition to existing commercially based PMU’s. The developed PMU was used in conjunction with the interconnected system along with the commercial PMU’s. The tested studies included a new technique for detecting the partially islanded micro grids in addition to several real-time techniques for synchronization and parameter identifications of hybrid systems.
Moreover, due to numerous integration of renewable energy resources through DC microgrids, this dissertation performs several practical cases for improvement of interoperability of such systems. Moreover, increased number of small and dispersed generating stations and their need to connect fast and properly into the AC grids, urged this work to explore the challenges that arise in synchronization of generators to the grid and through introduction of a Dynamic Brake system to improve the process of connecting distributed generators to the power grid.
Real time operation and control requires data communication security. A research effort in this dissertation was developed based on Trusted Sensing Base (TSB) process for data communication security. The innovative TSB approach improves the security aspect of the power grid as a cyber-physical system. It is based on available GPS synchronization technology and provides protection against confidentiality attacks in critical power system infrastructures.
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Basu, Prabal. „Toward Reliable, Secure, and Energy-Efficient Multi-Core System Design“. DigitalCommons@USU, 2019. https://digitalcommons.usu.edu/etd/7517.
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Computer hardware researchers have perennially focussed on improving the performance of computers while stipulating the energy consumption under a strict budget. While several innovations over the years have led to high performance and energy efficient computers, more challenges have also emerged as a fallout. For example, smaller transistor devices in modern multi-core systems are afflicted with several reliability and security concerns, which were inconceivable even a decade ago. Tackling these bottlenecks happens to negatively impact the power and performance of the computers. This dissertation explores novel techniques to gracefully solve some of the pressing challenges of the modern computer design. Specifically, the proposed techniques improve the reliability of on-chip communication fabric under a high power supply noise, increase the energy-efficiency of low-power graphics processing units, and demonstrate an unprecedented security loophole of the low-power computing paradigm through rigorous hardware-based experiments.
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Ševčík, Igor. „Koncepční návrh letounu s elektrickým pohonem“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-442673.
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The master’s thesis deals with conceptual design of a new electrically powered aircraft as assignment for Evektor, s.r.o. company. In the first part of thesis there is more detailed elaboration of small aircraft statistics and their comparison. Thesis then concentrates on assigned parameters and requirements for design. Next section continues with the most important part of thesis, which is optimization of wing used for aircraft design and also analysis of its characteristics. The problematics of preliminary verification of flight performances as well as aircraft dimension design and follow-up weight analysis with consideration of power cells placement is described thereafter. A few different flight configurations is taken into consideration within weight analysis. Final part contains evaluation of optimization and design process.
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Huang, Liling. „Electromechanical Wave Propagation in Large Electric Power Systems“. Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11054.
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In a large and dense power network, the transmission lines, the generators and the loads are considered to be continuous functions of space. The continuum technique provides a macro-scale analytical tool to gain an insight into the mechanisms by which the disturbances initiated by faults and other random events propagate in the continuum. This dissertation presents one-dimensional and two-dimensional discrete models to illustrate the propagation of electromechanical waves in a continuum system. The more realistic simulations of the non-uniform distribution of generators and boundary conditions are also studied. Numerical simulations, based on the swing equation, demonstrate electromechanical wave propagation with some interesting properties. The coefficients of reflection, reflection-free termination, and velocity of propagation are investigated from the numerical results. Discussions related to the effects of electromechanical wave propagation on protection systems are given. In addition, the simulation results are compared with field data collected by phasor measurement units, and show that the continuum technique provides a valuable tool in reproducing electromechanical transients on modern power systems. Discussions of new protection and control functions are included. A clear understanding of these and related phenomena will lead to innovative and effective countermeasures against unwanted trips by the protection systems, which can lead to system blackouts.Ph. D.
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Sobrinho, André Sanches Fonseca. „Desenvolvimento de uma unidade de medição fasorial otimizada para sistemas de distribuição“. Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18153/tde-05052016-114303/.
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Os sistemas elétricos de distribuição estão evoluindo rapidamente devido à penetração de geração distribuída e ao crescimento na utilização de avançadas estruturas de medição e sistemas de gerenciamento de distribuição de energia elétrica. Esta evolução traz consigo novos desafios devido à intermitência da geração, a qual pode gerar impactos indesejáveis nos sistemas de distribuição, como a interação de diferentes harmônicos. As Unidades de Medição Fasorial (PMUs) tem potencial para desempenhar um importante papel no monitoramento de sistemas elétricos de distribuição por meio dos fasores com medidas temporalmente sincronizadas de tensão e corrente em vários locais do sistema, oferecendo assim inúmeras possibilidades para estimar o estado de uma rede de distribuição. Porém, para serem utilizadas amplamente em redes de distribuição, é necessário que as PMUs apresentem um menor custo e possuam algumas características funcionais exclusivas para o uso nestas redes. Assim, o objetivo desta tese consiste no desenvolvimento de uma unidade de medição fasorial de baixo custo com características originais para o uso no nível de distribuição de energia elétrica, tais como medição fasorial nas redes de média e baixa tensão utilizando a modelagem dos transformadores e a identificação e estimação dos parâmetros da causa de ocorrência de distúrbios elétricos. Para isso, foram construídos dois protótipos da unidade de medição fasorial proposta neste trabalho, visando verificar a sincronização na medição de fasores de tensão e corrente. Os protótipos também foram acoplados à rede com diferentes combinações de impedância e alimentaram variadas cargas, onde foi possível através das técnicas implementadas nos equipamentos identificar e estimar os parâmetros elétricos da origem (rede ou carga) da ocorrência de variações na tensão e potência fornecidas pela rede distribuição.Power distribution systems are evolving at a high pace largely due to the proliferation of distributed energy resources and the growing utilization of advanced metering infrastructures and distribution management system. This evolution is also leading to new challenges due large penetration of intermittent distributed generation, which can lead to noticeable impacts on distribution feeders. Phasor Measurement Units (PMUs) have the potential to play an essential role in power distribution system monitoring. For providing synchronized measurements of voltage and current phasors at various system locations, PMUs offer numerous possibilities for ascertaining information relating to the state of the power distribution system. However, to be used widely in power distribution systems, its necessary that PMUs get a low cost and have some exclusive features for these systems. Thus, the main objective of this thesis have consisted of developing a low cost Phasor Measurement Unit with original features proposed for distribution level, such as compatibility with low and medium voltage power networks using transformer modeling and also the identification and parameter estimation of the cause of electrical disturbances. So, they were built two prototypes of the Phasor Measurement Unit, in order to verify the synchronization in the measurement of voltage and current phasors. The prototypes were also coupled to the network with different combinations of impedance and they fed varying loads, where it was possible through the techniques implemented in the equipment identify and estimate electrical parameters of the cause (network or load) of variations in voltage and power supplied by the network distribution.
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Schooley, David C. „Unit commitment and system reliability in electric utility systems with independent wind and solar generation“. Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/12917.
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Jiang, Chaomei. „Integration of interactive voice response unit and outage management system“. [Denver, Colo.] : Regis University, 2005. http://165.236.235.140/lib/CJiang2005.pdf.
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Mitwalli, Ahmed Hamdi. „A digital controller for a unity power factor converter“. Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/67135.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.Includes bibliographical references (leaves 153-154).
by Ahmed Mitwalli.
M.S.
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Douglas, Hugh. „A single three phase variable speed drive with unity power factor“. Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/5274.
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Bibliography: leaf 86.The new proposed topology for a single three-phase variable speed drive was developed after considering the advantages and disadvantages of previous topologies. The new topology employs only six switches that form and active front-end rectifier and a four-switch inverter. The active front-end rectifier is the first leg of the three-phase bridge. It not only rectifies the voltage source but it also regulates one of the phases for the motor. The four-switch inverter produces the variable frequency. Excessive distortion currents drawn by a converter can cause voltage distortions. For this reason the converter should draw a high quality sinusoidal current from the supply. Excessive currents drawn from the supply are also the result of poor power factors. The converter should therefore operate at close to unit power factor. N Mohan, T Underland, W.P Robins [3].
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Sheblé, Gerald B. „Unit commitment for operations“. Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/49977.
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The topic of unit commitment has been and continues to be of interest to many researchers and is a primary operation for most utilities. Past research has utilized integer programming, dynamic programming, linear programming, gradient, and heuristic techniques. This research combines both linear programming and dynamic programming for unit commitment decisions within a weekly time frame. The result provides most of the advantages of linear programming and dynamic programming with less stringent requirements on the pre solution information needed for unit transition sequences. Further, the research yields a new tool for the solution of the Transaction Evaluation problem.Ph. D.
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Wehbe, Yasser. „Model Estimation of Electric Power Systems by Phasor Measurement Units Data“. Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4419.
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This dissertation tackles the online estimation of synchronous machines' power subsystems electromechanical models using the output based Phasor Measurements Units (PMUs) data while disregarding any inside data. The research develops state space models
and estimates their parameters and states. The research tests the developed algorithms against models of a higher and of the same complexity as the estimated models.
The dissertation explores two estimations approaches using the PMUs data: i)non-linear Kalman filters namely the Extended Kalman Filter (EKF) and then the Unscented
Kalman Filter (UKF) and ii) Least Squares Estimation (LSE) with Finite Differences (FN) and then with System Identification. The EKF based research i) establishes a decoupling
technique for the subsystem the rest of the power system ii) finds the maximum number of parameters to estimate for classical machine model and iii) estimates such parameters
. The UKF based research i) estimates a set of electromechanical parameters and states for the flux decay model and ii) shows the advantage of using a dual estimation filter with
colored noise to solve the difficulty of some simultaneous state and parameter estimation.
The LSE with FN estimation i) evaluates numerically the state space differential equations and transform the problem to an overestimated linear system whose parameters
can be estimated, ii) carries out sensitivity studies evaluating the impact of operating conditions and iii) addresses the requirements for implementation on real data taken from
the electric grid of the United States. The System Identification method i) develops a linearized electromechanical model, ii) completes a parameters sub-set selection study using
si8ngular values decomposition, iii) estimates the parameters of the proposed model and iv) validates its output versus the measured output.
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Zheng, David Z. „Impacts of superconducting magnetic energy storage unit on power system stability“. Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-07112009-040323/.
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Austrin, Lars. „On magnetic amplifiers in aircraft applications“. Licentiate thesis, Stockholm : Elektrotekniska system, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4439.
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Clark, Laura L. „Design and Testing of a Quick-Connect Wheelchair Power Add-On Unit“. Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30289.
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A quick-connect wheelchair power add-on unit (PAU) has been developed at the Human Factors Engineering Center of Virginia Tech. The objective of the new invention is to provide an inexpensive, highly portable product which can quickly convert a manual wheelchair into a power-operated wheelchair. This dissertation details the three year research and design effort to develop the new wheelchair PAU. Results are presented from a series of evaluations conducted to identify performance and user-interaction characteristics of the PAU. Interpretation of the results provides a prioritized list of identified design deficiencies along with wheelchair expert and design team suggestions for the next generation of design alterations.
The three evaluations conducted with the second generation PAU prototype include a series of wheelchair expert interviews, a PAU performance evaluation, and a usability evaluation which utilized wheelchair operators as subjects. Also included in the dissertation is an explanation of the need for a new PAU, a description of the most recent design iteration, a literature review containing information about the history of wheelchairs, the condition of the current PAU market, and an analysis of wheelchair PAU consumers.
The new invention was conceived and patented by Dr. John G. Casali of the Industrial and Systems Engineering (ISE) Department at Virginia Tech. This research was supported jointly by Southwestern Applied Technologies, L. C., of Roanoke, Virginia and Virginia's Center for Innovative Technology in Herndon, Virginia.Ph. D.
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Eissa, Mohamed O. (Mohamed Omer). „A fast analog controller for a unity power factor AC/DC converter“. Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/106709.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.Includes bibliographical references (leaves 108-109).
by Mohamed O. Eissa.
M.S.
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Pantshwa, Athini. „Analysis of the reliability for the 132/66/22 KV distribution network within ESKOM’s Eastern Cape operating unit“. Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/19750.
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A stable and reliable electrical power supply system is an inevitable pre-requisite for the technological and economic growth of any nation. Due to this, utilities must strive and ensure that the customer’s reliability requirements are met and that the regulators requirements are satisfied at the lowest possible cost. It is known fact around the world that 90% of the customer service interruptions are caused due to failure in distribution system. Therefore, it is worth considering reliability assessments as it provides an opportunity to incorporate the cost or losses incurred by the utilities customer as a result of power failure. This must be considered in the planning and operating practices. The system modelling and simulation study is carried out on one of the district’s distribution system which consists of 132 kV, 66 kV and 22 kV network in Aliwal North Sector ECOU. The reliability assessment is done on the 22, 66 and 132 kV system to assess the performance of the present system and also predictive reliability analysis for the future system considering load growth and system expansion. The alternative which gives low SAIDI, SAIFI and minimum breakeven costs is being assessed and considered. The reliability of 132 kV system could be further improved by constructing a new 132 kV line from a different source of supply and connecting with line coming from another district (reserve) at reasonable break even cost. The decision base could be further improved by having Aliwal North Sector context interruption cost. However, the historical data which may be used in Aliwal North Sector to acquire interruption costs from the customers are being proposed. The focus should be on improving the power quality on constrained networks first, then the reliability. Therefore for the Aliwal North power system network it is imperative that Eskom invest on the reliability of this network. This dissertation also analysed load reflected economic benefit versus performance expectations that should be optimized through achieving a balance between network performance (SAIDI) improvement, and total life cycle cost (to Eskom as well as the economy). Reliability analysis conducted in this dissertation used Aliwal North power system network as a case study; the results proved that the system is vulnerable to faults, planned and unplanned outages. Reliability evaluation studies were conducted on the system using DigSilent software in conjunction with FME. These two models gave accurate results with acceptable variance in most indices except for the ENS where the variance was quite significant. It can be concluded that DigSilent results are the most accurate results in all three reliability evaluation scenarios for the Aliwal North Power System, best interpretation being that of DigSilent.
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Tunc, Murat. „A Single Transistor Unity Power Factor Rectifier“. Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608114/index.pdf.
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This thesis analyzes unity power factor rectifiers since this type of rectifiers use energy as efficient as possible. Throughout the thesis, some unity power factor rectifier topologies are investigated and some of them selected to investigate in detail. Afterwards, a new single transistor unity power factor rectifier topology is proposed, simulated, implemented and compared with one of the selected unity power factor rectifier topology on the basis of efficiency, total harmonic distortion, input current ripple and output voltage ripple.
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Grey, Audley Bruce. „Unified solution of security-constrained unit commitment (SCUC) problem using a linear programming methodology : a dissertation presented to the faculty of the Graduate School, Tennessee Technological University /“. Click to access online version, 2007. http://proquest.umi.com/pqdweb?index=88&did=1397913351&SrchMode=1&sid=1&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1255446163&clientId=28564.
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Oubrahim, Zakarya. „On electric grid power quality monitoring using parametric signal processing techniques“. Thesis, Brest, 2017. http://www.theses.fr/2017BRES0102/document.
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Cette thèse porte sur la surveillance des perturbations de la qualité de l’énergie d’un réseau électrique via des techniques paramétriques de traitement du signal. Pour élaborer nos algorithmes de traitement du signal, nous avons traité les problèmes d’estimation des différentes grandeurs du réseau électrique triphasé et de classification des perturbations de la qualité d'énergie. Pour ce qui est du problème d’estimation, nous avons développé une technique statistique basée sur le maximum de vraisemblance. La technique proposée exploite la nature multidimensionnelle des signaux électriques. Elle utilise un algorithme d’optimisation pour minimiser la fonction de vraisemblance. L’algorithme utilisé permet d’améliorer les performances d’estimation tout en étant d’une faible complexité calculatoire en comparaison aux algorithmes classiques. Une analyse plus poussée de l’estimateur proposé a été effectuée. Plus précisément, ses performances sont évaluées sous un environnement incluant entre autres la pollution harmonique et interharmonique et le bruit. Les performances sont également comparées aux exigences de la norme IEEE C37.118.2011. La problématique de classification dans les réseaux électriques triphasés a plus particulièrement concerné les perturbations que sont les creux de tension et les surtensions. La technique de classification proposée consiste globalement en deux étapes : 1) une pré-classification du signal dans l’une des 4 préclasses établis et en 2) une classification du type de perturbation à l’aide de l’estimation des composants symétriques.Les performances du classificateur proposé ont été évaluées, entre autres, pour différentes nombre de cycles, de SNR et de THD. L’estimateur et le classificateur proposés ont été validés en simulation et en utilisant les données d’un réseau électrique réel du DOE/EPRI National Database of Power System Events. Les résultats obtenus illustrent clairement l’efficacité des algorithmes proposés quand à leur utilisation comme outil de surveillance de la qualité d’énergieThis thesis deals with electric grid monitoring of power quality (PQ) disturbances using parametric signal processing techniques. The first contribution is devoted to the parametric spectral estimation approach for signal parameter extraction. The proposed approach exploits the multidimensional nature of the electrical signals.For spectral estimation, it uses an optimization algorithm to minimize the likelihood function. In particular, this algorithm allows to improve the estimation accuracy and has lower computational complexity than classical algorithms. An in-depth analysis of the proposed estimator has been performed. Specifically, the estimator performances are evaluated under noisy, harmonic, interharmonic, and off-nominal frequency environment. These performances are also compared with the requirements of the IEEE Standard C37.118.2011. The achieved results have shown that the proposed approach is an attractive choice for PQ measurement devices such as phasor measurement units (PMUs). The second contribution deals with the classification of power quality disturbances in three-phase power systems. Specifically, this approach focuses on voltage sag and swell signatures. The proposed classification approach is based on two main steps: 1) the signal pre-classification into one of 4 pre-classes and 2) the signature type classification using the estimate of the symmetrical components. The classifier performances have been evaluated for different data length, signal to noise ratio, interharmonic, and total harmonic distortion. The proposed estimator and classifier are validated using real power system data obtained from the DOE/EPRI National Database of Power System Events. The achieved simulations and experimental results clearly illustrate the effectiveness of the proposed techniques for PQ monitoring purpose
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Hernandez, Jorge Eliezer. „Third harmonic management and flexible charging for the integration of electric vehicles into the grid“. Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53495.
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Electric vehicle (EV) development has gone into an accelerated pace in recent years to address pressing concerns on energy security, the environment, and the sustainability of transportation. The future market success of EVs is still uncertain, but the current shift in the automotive industry is indicating a possible bright future for EVs. Because of its unique load characteristics, an extensive deployment of EVs will not only bring challenges to power systems, but will enable new opportunities as well. The objective of this work is to address the increased third harmonic currents expected with the introduction of EVs and to explore the potential of leveraging flexible EV charging to increase wind power production.
Since EV chargers rely on a nonlinear power conversion process to obtain a controllable DC source from the utility AC supply, it is expected that these devices will aggravate third harmonic current issues. In fact, utility harmonic field data show that, even without EVs, distribution feeders are already experimenting elevated levels of third harmonic currents. To address present and future utility harmonic filtering needs, a practical third harmonic hybrid active filter for medium voltage (MV) applications is proposed. Its design is based on strict utility requirements of cost, reliability, and ease of system implementation. The operation and performance of the proposed filter is verified through simulations and two experimental setups, one tested at 7.2 kV. Furthermore, a system impact study of the proposed filter is performed using actual data for a typical residential/small commercial distribution feeder.
Because vehicles remain stationary most of the time, EVs have the potential of being flexibly charged, providing a spectrum of opportunities for system operators. The recent increase in wind power penetration in the U.S. is raising concerns on how to accommodate this stochastic renewable energy resource in day-ahead scheduling operations. In this work, a detailed integrated day-ahead scheduling framework is developed to explore the impact of leveraging flexible EV charging to balance out the variability and uncertainty of wind power generation. It is determined that the full benefits of balancing wind power generation with flexible EV charging may not be achieved in congested power systems. A potential solution based on deploying power routers (PRs) to augment the flexibility of the transmission system is proposed. Simulation results are presented for a test system based on the IEEE 39-bus system.
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Scarsi, Gian Carlo. „Electricity distribution in Italy : microeconomic efficiency analysis of local distributing units with methodological cross-checking“. Thesis, University of Oxford, 1998. http://ora.ox.ac.uk/objects/uuid:ca322a0b-7fd0-4a02-a237-bb4b6f02eeda.
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This thesis analyses technical efficiency of local electricity distribution in Italy (1994, 1996) by using both econometric (deterministic frontier, stochastic frontier) and linear programming (Data Envelopment Analysis) tools. Cross-sectional data was examined with respect to (a) ENEL - the Italian electricity monopolist whose restructuring and privatisation is now under way - and its local distribution branches (Chapters 2, 3, and 5); (b) municipal authorities (MUNIs), i.e. town-based electric utilities which sometimes hold franchises for electricity distribution within city limits (Chapters 4 and 5). Estimation results from Chapters 2 and 3 highlighted non-exhaustion of scale economies at sample-mean values. Scope economies between medium and low-voltage distribution were also detected (Ch. 2). Efficiency score series stemming from both econometric and linear programming techniques in Chapters 3 and 5 showed that Southern distributors were relatively under-represented among top units even after allowing for several exogenous environmental variables. The external effects which proved to influence technical efficiency in electricity distribution were consumer density, the percentage of industrial customers, the geographical nature of areas served (metropolitan areas, mountains, etc.), and the interaction between ENEL's units and municipal utilities in those towns featuring ENEL and MUNIs bordering each other. Pooled ENEL-MUNI analysis from Chapter 4 failed to spot any systematic superiority of ENEL's units over municipalities. Generalisation on the ENEL-MUNI efficiency dispute was then discarded, in favour of case-by-case comparison. Paired-samples statistical testing (both parametric and non-parametric) from Chapter 5 showed limited agreement between Stochastic Frontier Estimation (SFE) and Data Envelopment Analysis (DEA) efficiency outcomes. Statistical concordance was more often found when comparing SFE and DEA models sharing the same input-output specification. Again, no apparent superiority of ENEL over MUNIs was found out by DEA linear programs. One-to-one comparisons confirmed that the outcomes were mixed, with ENEL's local branches outperforming MUNIs in metropolitan and (sometimes) rural areas, and MUNIs faring better in medium-sized, Po Valley towns (Northern Italy). Results were not clear-cut for Alpine and rural distributors. The latter however - should be considered on a separate basis in that they will probably need permanent subsidies to meet universal service obligations, irrespective of the future structure of electricity distribution in Italy. Comparable (e.g., urban) units might - on the other hand - be subject to yardstick regulation based upon DEA's 'efficient peer' outcomes. Apart from the main empirical work, this thesis also features institutional and theoretical overviews (Chapters 2 to 5) with relevant literature surveys, a DEA Numerical Appendix (Chapter 5), and a regional map of the Italian territory (end of thesis).
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Kamireddy, Srinath. „Comparison of state estimation algorithms considering phasor measurement units and major and minor data loss“. Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-11072008-121521.
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Beltran, Royo César. „Generalized unit commitment by the radar multiplier method“. Doctoral thesis, Universitat Politècnica de Catalunya, 2001. http://hdl.handle.net/10803/6501.
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This operations research thesis should be situated in the field of the power generation industry. The general objective of this work is to efficiently solve the Generalized Unit Commitment (GUC) problem by means of specialized software. The GUC problem generalizes the Unit Commitment (UC) problem by simultane-ously solving the associated Optimal Power Flow (OPF) problem. There are many approaches to solve the UC and OPF problems separately, but approaches to solve them jointly, i.e. to solve the GUC problem, are quite scarce. One of these GUC solving approaches is due to professors Batut and Renaud, whose methodology has been taken as a starting point for the methodology presented herein.This thesis report is structured as follows. Chapter 1 describes the state of the art of the UC and GUC problems. The formulation of the classical short-term power planning problems related to the GUC problem, namely the economic dispatching problem, the OPF problem, and the UC problem, are reviewed. Special attention is paid to the UC literature and to the traditional methods for solving the UC problem. In chapter 2 we extend the OPF model developed by professors Heredia and Nabona to obtain our GUC model. The variables used and the modelling of the thermal, hydraulic and transmission systems are introduced, as is the objective function. Chapter 3 deals with the Variable Duplication (VD) method, which is used to decompose the GUC problem as an alternative to the Classical Lagrangian Relaxation (CLR) method. Furthermore, in chapter 3 dual bounds provided by the VDmethod or by the CLR methods are theoretically compared.
Throughout chapters 4, 5, and 6 our solution methodology, the Radar Multiplier (RM) method, is designed and tested. Three independent matters are studied: first, the auxiliary problem principle method, used by Batut and Renaud to treat the inseparable augmented Lagrangian, is compared with the block coordinate descent method from both theoretical and practical points of view. Second, the Radar Sub- gradient (RS) method, a new Lagrange multiplier updating method, is proposed and computationally compared with the classical subgradient method. And third, we study the local character of the optimizers computed by the Augmented Lagrangian Relaxation (ALR) method when solving the GUC problem. A heuristic to improve the local ALR optimizers is designed and tested.
Chapter 7 is devoted to our computational implementation of the RM method, the MACH code. First, the design of MACH is reviewed brie y and then its performance is tested by solving real-life large-scale UC and GUC instances. Solutions computed using our VD formulation of the GUC problem are partially primal feasible since they do not necessarily fulfill the spinning reserve constraints. In chapter 8 we study how to modify this GUC formulation with the aim of obtaining full primal feasible solutions. A successful test based on a simple UC problem is reported. The conclusions, contributions of the thesis, and proposed further research can be found in chapter 9.
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Albadri, Rand. „Jämförande analys av driftsäkerhet medRTU och PLC“. Thesis, Högskolan Väst, Avdelningen för data-, elektro- och lantmäteriteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-8190.
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Examensarbetet kommer att göra en jämförande analys av driftsäkerhet med trådade signaler till en Remote Terminal Unit (RTU) och en Programmable Logic Controller (PLC) med busstyrning. Rapporten genomfördes som ett uppdrag av Skellefteå Kraft AB för att se om det möjligt att byta till PLC- med busstyrning. Rapporten redogör för grundläggande beskrivning för skillnaden mellan de här två system och kommer att undersöka vilken som är driftsäkrare och lönsammare med hänsyn till krav enligt Svenska Kraftföretagens riktlinjer för dammsäkerhet (Ridas).Med hjälp av kurslitteratur, ABB handboken, internet websidor samt intervjuar med Skellefteå Kraft AB:s personal har arbetets resultat visat att busstyrning med PLC kommer att fungera driftsäkert samt kommer att bli lönsamt jämfört med trådade signaler till RTU. Resultat visat även att det finns ingenting som hindrar att installera busstyrning enligt Ridas men vissa funktioner bör installeras. Rapporten är avgränsat genom att inte ta upp eventuella krav från miljöbalken.This thesis will make a comparative analysis of the operation safety of the wire connection to Remote Terminal Unit (RTU) and Programmable Logic Controller (PLC) with bus-controller. The report describes the basic description of the difference between these two systems and will explore which is safer and more economic with consideration to qualification according to Swedish energy companies' guidelines for dam safety (Ridas).Through course literature, ABB Bok, internet web sits and interviews with Skellefteå Kraft AB staff the result of this report have been created.The report results prove that PLC with bus-controller will operate operationally safe and profitable compared to wire connection to RTU. Results also showed that there is nothing which prevents to install bus-controller according to RIDAS but certain features should be installed.
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Valverde, Mora Gustavo Adolfo. „Uncertainty and state estimation of power systems“. Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/uncertainty-and-state-estimation-of-power-systems(18c48a22-7ea2-4db2-9112-078a1eac6fe7).html.
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The evolving complexity of electric power systems with higher levels of uncertainties is a new challenge faced by system operators. Therefore, new methods for power system prediction, monitoring and state estimation are relevant for the efficient exploitation of renewable energy sources and the secure operation of network assets. In order to estimate all possible operating conditions of power systems, this Thesis proposes the use of Gaussian mixture models to represent non-Gaussian correlated input variables, such as wind power output or aggregated load demands in the probabilistic load flow problem. The formulation, based on multiple Weighted Least Square runs, is also extended to monitor distribution radial networks where the uncertainty of these networks is aggravated by the lack of sufficient real-time measurements. This research also explores reduction techniques to limit the computational demands of the probabilistic load flow and it assesses the impact of the reductions on the resulting probability density functions of power flows and bus voltages. The development of synchronised measurement technology to support monitoring of electric power systems in real-time is also studied in this work. The Thesis presents and compares different formulations for incorporating conventional and synchronised measurements in the state estimation problem. As a result of the study, a new hybrid constrained state estimator is proposed. This constrained formulation makes it possible to take advantage of the information from synchronised phasor measurements of branch currents and bus voltages in polar form. Additionally, the study is extended to assess the advantages of PMU measurements in multi-area state estimators and it explores a new algorithm that minimises the data exchange between local area state estimators. Finally, this research work also presents the advantages of dynamic state estimators supported by Synchronised Measurement Technology. The dynamic state estimator is compared with the static approach in terms of accuracy and performance during sudden changes of states and the presence of bad data. All formulations presented in this Thesis were validated in different IEEE test systems.
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Lemieux, Christine. „La coopération politique bilatérale entre le Canada et les États-Unis dans le secteur énergétique : l'harmonisation des normes de fiabilité reliées au transport de l'électricité“. Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99730.
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Do domestic variables matter in a context of bilateral cooperation? What factors positively influence the decision-making process in the case of a policy harmonization between two countries? By studying both countries' institutional differences and governmental and non-governmental actors' preferences in the energy sector, this research analyzes the bilateral cooperation between Canada and the United States regarding the creation of the Electric Reliability Organization. Although domestic institutional constraints are important to consider, I argue that both physical and economic market integration and the use of a non-governmental organization by central governments have facilitated the success of the cooperation process. Those factors have favored the convergence of decisional actors' preferences and the inclusion of the majority of actors from all sectors of the industry into the process. The analysis uses a sequential model implying the division decision-making process over foreign policy into specific stages to show the importance of domestic variables.Key words: Governmental cooperation, bilateral relations, actors' preferences, institution, energy sector, electricity, transmission network, reliability standards, market integration, restructured electricity market.
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Sahin, Cem. „Optimization Of Electricity Markets In The Price Based And Security Constrained Unit Commitment Problems Frameworks“. Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612242/index.pdf.
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Operation of the electricity markets is subject to a number of strict and specific constraints such as continuous load-generation balance, security of supply, and generation technology related limitations. Contributions have been made to two important problems of the Electricity Markets, in the context of this study.
In this study, Price Based Unit Commitment problem in the literature, which is a tool for the GENCO for operations planning, is extended considering the interdependencies between the Natural Gas (NG) and Electricity infrastructures and the uncertainty of Wind Power generation. The effect of the NG infrastructure physical limitations is considered via linearized NG transmission system equations, and the Wind energy sources and conventional generation resource uncertainties are simulated by Monte-Carlo simulations. The contribution of the forward energy Bilateral Contracts (BC), as a financial risk hedging tool is also included by modeling these in the proposed PBUC framework. In the case studies , it is observed that a GENCO could prevent its financial losses due to NG interruptions, by depositing only a portion of the midterm interrupted NG in the storage facilities.
The Security Constrained Unit Commitment (SCUC) Problem is widely accepted tool in the industry which models the market clearing process. This study integrates two novelties to the SCUC problem&bull
A discrete demand response model to consider active participation of the consumers, &bull
A hybrid deterministic/stochastic contingency model to represent the N-1 contingencies together with the uncertainties related with the wind power generation and system load. It is observed that the curtailment of available wind power capacity would enable the TSO to take corrective actions against occurrence of the contingencies and realization of the uncertainties in the most possible economical manner.
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Lopez, Miguel. „CONTRIBUTION A L'OPTIMISATION D'UN SYSTEME DE CONVERSION EOLIEN POUR UNE UNITE DE PRODUCTION ISOLEE“. Phd thesis, Université Paris Sud - Paris XI, 2008. http://tel.archives-ouvertes.fr/tel-00344978.
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La demande énergétique mondiale en constante augmentation, l'instabilité et l'incertitude du prix des énergies fossiles, la libéralisation du marché électrique et une conscience environnementale renforcée durant ces dernières années ont renouvelé l'intérêt du développement des énergies renouvelables. Parmi elles, l'énergie éolienne détient une situation privilégiée grâce à son progrès technologique et à ses coûts associés comparativement faibles. Dans ce contexte, l'apport envisagé avec ce travail de thèse est de collaborer à la conception optimale d'un système de production éolien isolé de petite taille, pour les sites où l'extension du réseau est difficile ou trop coûteuse. Un outil d'optimisation pour un système de génération éolien chargeur de batterie est proposé et validé. Le système de puissance est composé d'une quantité minimale d'éléments. De cette façon, la simplicité du système permet de réduire les efforts de maintenance et d'augmenter sa fiabilité à un coût minimal. Lorsqu'une production plus élevée est désirée, avec les mêmes moyens de production (turbine et générateur), une structure qui inclut un convertisseur électronique de puissance commandé par MLI est utile. Un tel système est étudié et vérifié par simulation numérique. Ce système ainsi modifié permet un transfert de puissance optimal, ce qui augmente la production d'énergie et peut ainsi réduire son coût. Une méthode d'estimation des pertes dans les convertisseurs statiques est aussi proposée et validée. Elle est utilisée pour calculer de façon plus précise l'énergie non fournie d'un système de génération hybride renouvelable installé en site isolé.
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Ahmed, Sheikh. „PMU based PSS and SVC fuzzy controller design for angular stability analysis“. Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20547.
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Master of ScienceDepartment of Electrical and Computer Engineering
Shelli Starrett
Variability in power systems is increasing due to pushing the system to limits for economic purposes, the inclusion of new energy sources like wind turbines and photovoltaic, and the introduction of new types of loads such as electric vehicle chargers. In this new environment, system monitoring and control must keep pace to insure system stability and reliability on a wide area scale. Phasor measurement unit technology implementation is growing and can be used to provide input signals to new types of control. Fuzzy logic based power system stabilizer (PSS) controllers have also been shown effective in various studies. This thesis considers several choices of input signals, composed assuming phasor measurement availability, for fuzzy logic-based controllers. The purpose of the controller is to damp power systems’ low frequency oscillations. Nonlinear transient simulation results for a 4-machine two-area system and 50 machine system are used to compare the effects of input choice and controller type on damping of system oscillations. Reactive power in the system affects voltage, which in turn affects system damping and dynamic stability. System stability and damping can be enhanced by deploying SVC controllers properly. Different types of power system variables play critical role to damp power swings using SVC controller. A fuzzy logic based static var compensator (SVC) was used near a generator to damp these electromechanical oscillations using different PMU-acquired inputs. The goal was again improve dynamic stability and damping performance of the system at local and global level. Nonlinear simulations were run to compare the damping performance of different inputs on the 50 machine system.
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Katariya, Ashish Santosh. „Dynamic modeling and feedback control with mode-shifting of a two-mode electrically variable transmission“. Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45825.
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This thesis develops dynamic models for the two-mode FWD EVT, develops a control system based on those models that is capable of meeting driver torque demands and performing synchronous mode shifts between different EVT modes while also accommodating preferred engine operating points. The two-input two-output transmission controller proposed herein incorporates motor-generator dynamics, is based on a general state-space integral control structure, and has feedback gains determined using linear quadratic regulator (LQR) optimization.
Dynamic modeling of the vehicle is categorized as dynamic modeling of the mechanical and electrical subsystems where the mechanical subsystem consists of the planetary gear sets, the transmission and the engine whereas the electrical subsystem consists of the motor-generator units and the battery pack. A discussion of load torque is also considered as part of the mechanical subsystem. With the help of these derived dynamic models, a distinction is made between dynamic output torque and steady-state output torque.
The overall control system consisting of multiple subsystems such as the human driver, power management unit (PMU), friction brakes, combustion engine, transmission control unit (TCU) and motor-generator units is designed. The logic for synchronous mode shifts between different EVT modes is also detailed as part of the control system design. Finally, the thesis presents results for responses in individual operating modes, EVT mode shifting and a full UDDS drive cycle simulation.
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Shields, Shawn. „Dynamic thermal response of the data center to cooling loss during facility power failure“. Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29725.
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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2010.Committee Chair: Yogendra K. Joshi; Committee Member: Mostafa Ghiaasiaan; Committee Member: Sheldon Jeter. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Warichet, Jacques. „From the measurement of synchrophasors to the identification of inter-area oscillations in power transmission systems“. Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209511.
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In the early 1980s, relaying engineers conceived a technology allowing a huge step forward in the monitoring of power system behavior: the synchrophasor, i.e. the estimation of a phasor representation - amplitude and phase - of a sinusoidal waveform at a given point in time thanks to highly accurate time synchronization of a digital relay. By measuring synchrophasors across the power system several times per second, and centralizing the appropriate information in a hierarchical way through a telecommunication network link, it is now possible to continuously monitor the state of very large systems at a high refresh rate. At the beginning, the phase angle information of synchrophasors was used to support or improve the performance of classic monitoring applications, such as state estimation and post-mortem analysis. Later, synchrophasors were found to be valuable for the detection and analysis of phenomena that were not monitored previously, such as system islanding and angular stability. This allows a better understanding of system behavior and the design of remedial actions in cases where system security appears to be endangered. Early detection and even prediction of instabilities, as well as validation and improvement of the dynamic models used for studies, have thus become possible.
However, a power system is rarely stationary and the assumptions behind the definition of “phasor” are not completely fulfilled because the waveforms' frequency and amplitude are not constant over a signal cycle at fundamental frequency. Therefore, accuracy of synchrophasor measurements during dynamic events is an important performance criterion. Furthermore, when discontinuities (phase jumps and high magnitude variations) and harmonics disturb the measured analog signals as a consequence of switching actions or external disturbances, measurements provided to the “user” (the operator or the algorithms that will take decisions such as triggering alarms and remedial actions) require a certain robustness.
The efforts underpinning this thesis have lead to the development of a method that ensures the robustness of the measurement. This scheme is described and tested in various conditions. In order to achieve a closer alignment between required and actual measurement performance, it is recommended to add an online indicator of phasor accuracy to the phasor data.
Fast automated corrective actions and closed-loop control schemes relying on synchrophasors are increasingly deployed in power systems. The delay introduced in the measurement and the telecommunication can have a negative impact on the efficiency of these schemes. Therefore, measurement latency is also a major performance indicator of the synchrophasor measurement.
This thesis illustrates the full measurement chain, from the measurement of analog voltages and currents in the power system to the use of these measurements for various purposes, with an emphasis on real-time applications: visualization, triggering of alarms in the control room or remedial actions, and integration in closed-loop controls. It highlights the various elements along this chain, which influence the availability, accuracy and delay of the data.
The main focus is on the algorithm to estimate synchrophasors and on the tradeoff between accuracy and latency that arises in applications for which measurements are taken during dynamic events and the data must be processed within a very limited timeframe.
If both fast phasors and slower, more accurate phasors are made available, the user would be able to select the set of phasors that are the most suitable for each application, by giving priority to either accuracy or a short delay.
This thesis also tentatively identifies gaps between requirements and typical measurements in order to identify current barriers and challenges to the use of wide area measurement systems.
A specific application, the continuous monitoring of oscillatory stability, was selected in order to illustrate the benefits of synchrophasors for the monitoring, analysis and control of power system behavior. This application requires a good phasor accuracy but can allow for some measurement delay, unless phasor data are used in an oscillation damping controller. In addition, it also relies on modal estimators, i.e. techniques for the online identification of the characteristics of oscillatory modes from measurements. This field of ongoing research is also introduced in this thesis.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Třináctý, Jiří. „Parní turbína pro fosilní elektrárnu“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231811.
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This thesis deals with design is condensing steam turbines burning fossil fuels with nominal capacity of the generator of 250 MW with steam reheating and regenerative eight uncontrolled extraction points. The turbine consists of two bodies: a combined high-intermediate pressure section and low pressure parts with dual way outlet down into the water-cooled condenser. Work includes calculating thermal scheme for 100% and 75% capacity, specific heat consumption calculation and design of the flow HP-MP body. Further strength control and basic engineering design of high-medium- work completed by longitudinal section. Achievements are at the end of work compared with work 3a and the conclusion summarizes the advantages and disadvantages of the concept.
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Kim, Bunthern. „Contribution to the design and control of a hybrid renewable energy generation system based on reuse of electrical and electronics components for rural electrification in developing countries“. Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0041/document.
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Bien que le gouvernement cambodgien s’efforce d’augmenter sa production d’électricité pour répondre à sa demande en énergie, il reste toujours dépendant de réseau électrique existant ou de l’extension du réseau dont le coût d’investissement initial est élevé. La solution temporelle consiste à employer un système de production d'énergie distribué qui présente un coût de cycle de vie inférieur et introduit une diversité de technologies pour répondre aux applications. Minimiser les impacts environnementaux représente un objectif majeur du développement durable, compte tenu de l'épuisement des ressources et des capacités d'adaptation limitées de l'environnement. Les ressources en énergies renouvelables ont été bien comprises comme les solutions pour alimenter le développement rural et réduire les impacts environnementaux de la production d’énergie. Suivant les progrès technologiques et de la demande croissante des consommateurs, de grande quantité de déchets électriques et électroniques ont entraîné de graves conséquences pour l’environnement. Les stratégies actuelles reposent principalement sur les techniques classiques de collecte et de traitement des déchets. Ce travail de thèse proposait une solution de réutilisation des composants électroniques dans un système d'énergie renouvelable hybride isolé pour la solution d'électrification pour la zone rurale. Une configuration choisie pour le système proposé est un système de génération hybride solaire-hydroélectrique, car les ressources solaires et hydrauliques sont abondantes dans les zones rurales du Cambodge. Les composants qui sont réutilisés dans la solution comprennent des blocs d’alimentation d’un PC (PSU) pour la partie solaire, des alimentations sans interruption (UPS) et des machines asynchrone triphasées pour la partie hydraulique. Les batteries automobiles usagées sont utilisées pour le stockage d’énergie. Ce travail de thèse aborde dans une première partie l’évaluation des impacts environnementaux de la solution de réutilisation proposée. Cette étude repose sur la méthodologie de l’Analyse du Cycle de Vie (ACV) qui compare les impacts du cycle de vie de la solution proposée à ceux d’une solution conventionnelle. La deuxième partie de ce travail traite des aspects technologiques de la solution de réutilisation, à la fois en théorie et en expérimentation. La première partie de cet aspect concerne la reconversion des blocs d’alimentations usagées. Le bloc d'alimentation, qui contient généralement l'un des quelques types de convertisseurs DC-DC isolés, est réutilisé comme contrôleur de charge, qui est le composant principal du système de générateur photovoltaïque. La dernière partie de cette thèse décrit une nouvelle configuration de générateur basé sur des moteurs asynchrone triphasés. Le générateur monophasé proposé basé sur une machine triphasée est une version modifiée d'une topologie à base de l’onduleur où deux enroulements sont alimentés séparément par sources d'excitation, et l'autre enroulement est connecté à la charge. Une nouvelle modélisation est proposée. Les résultats de simulation sont comparés aux résultats expérimentaux en alimentation sinus. La comparaison met en évidence une supériorité de la nouvelle configuration par rapport à l'ancienne en termes de rendement et de minimisation de pulsations de coupleWhile the Cambodia’s government is making effort to increase electricity production for its energy demand, it still remains dependent on the existing or the expansion of the centralized grid lines which have high initial investment cost. The temporally solution is to employ a distributed energy generation system which has lower life cycle cost and provides a diversity of technologies to meet the desired applications. Minimizing environmental impacts represents a major objective of sustainable development considering resources depletion and the limited capabilities of the environment to adapt. The potential of renewable energy resources has been well understood as the solutions to power rural development and to reduce the environmental impacts of energy generation. Due to advance in technologies and increasing consumer demands, there has been a vast amount of electrical and electronic waste which introduces severe impacts on the environment. The current strategies mainly rely on conventional waste collection and processing techniques for material recovery. This thesis proposed a solution of reusing discarded components in an isolated hybrid renewable energy system as the solution for electrification of rural Cambodia. This is frugal innovation, local solution with local materials for and with local people. A suitable configuration for the proposed system is a solar-hydro hybrid generation system since solar and water resources are plentiful in rural Cambodia. The components that are reused in the solution after being discarded include computer power supply units (PSUs) for the solar part, uninterruptable power supply units (UPSs) and three phase induction machines for the electrohydro part. Used auto-mobile batteries will be used for the system storage. The thesis presents in the first part the evaluation of the environmental impacts of the proposed reuse solution for rural electrification. The study of the environmental impacts is based on Life Cycle Assessment (LCA) methodology which compares the life cycle impacts of the proposed solution to that of a conventional solution. Moreover, a sensitivity analysis is achieved in order to evaluate the impacts of uncertainties of the environmental impacts. The second part of this work deals with the technological aspects of the reuse solution in both theory and experimentation. The first part of this aspect is focused on the repurposing of used computer power supply units (PSUs), through limited modifications of the circuits in order to increase its range of operation. The PSU which usually contains one of a few types of isolated DC-DC converters is repurposed as charge controller with MPPT control in a cheap micro-controller with very good results. The last part of this thesis studies a new configuration of generators based on re-used three-phase induction motors. The proposed single-phase generator is based on a three-phase machine in a modified version of the coupling and with a rather uncommon supply. Modelling is highly investigated. An inverterassisted topology where two windings will be supplied separately by two inverters for excitation and the remaining winding is connected to load. A new modeling of the generator has been studied. The results of simulation were compared to experimental test results in open loop study. These results have demonstrated the advantages of the new configuration in comparison to the previously proposed inverter-assisted topology in term of efficiency and minimization of torqueripple
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Upadhyay, Abhishek Kumar. „A GENERALIZED CONTROL METHOD FOR CONSTANT SWITCHING FREQUENCY THREE PHASE PWM BOOST RECTIFIER UNDER EXTREME UNBALANCED OPERATION CONDITION“. Cleveland State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=csu1449719352.
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