Thèses sur le sujet « Operative plans »
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1
Doležal, Tomáš. « Business Plan : The Development and Operation of Biomass Power Plant ». Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-125031.
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The goals of this thesis are to create a comprehensive business plan manual from various business plan frameworks and to clarify project documentation necessary for the commencement of the biomass power plant. The theoretical part serves to the reader as a manual, how to write a business plan. In each section the thesis lists necessary questions to be answered, the theory and the recommendations what to include in the business plan. The practical part represents a complete business plan of the development and op-eration of the biomass power plant with focus on the political analysis, key resources and financial analysis. In the end of the thesis the investment decision criteria are pre-sented together with the risks analysis, providing a solid information base upon which a potential investor can decide, whether to invest into the project.
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Rosso, Stefano. « Power Plant Operation Optimization Economic dispatch of combined cycle power plants ». Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264350.
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As electricity production from renewable sources increases, higher flexibility is required by fossil fuel generation to cope with the inherent fluctuations of solar and wind power. This results in shorter operating cycles and steeper ramps for the turbines, and more uncertainty for the operators. This thesis work applies mathematical optimization and statistical learning to improve the economic dispatch of a combined cycle power plant composed by two separate blocks of two gas turbines and one steam turbine. The goal is to minimize the input fuel to the gas turbines while respecting a series of constraints related to the demand the plant faces, power generation limits etc. This is achieved through the creation of a mathematical model of the plant that regulates how the plant can operate. The model is then optimized to reduce fuel consumption at a minimum. Machine learning techniques have been applied to sensor data from the plant itself to realistically simulate the behavior of the turbines. Input-Output curves have been obtained for power and exhaust heat generation of all the turbines using ordinary least squares on monthly data with a ten minutes sampling rate. The model is cross-validated and proven statistically valid. The optimization problem is formulated through generalized disjunctive programming in the form of a mixed-integer linear problem (MILP) and solved using a branch-and-bound algorithm. The output of the model is a one-week dispatch, in fifteen minutes intervals, carried out for two months in total. Lower fuel consumption is achieved using the optimization model, with a weekly reduction of fuel consumed in the range of 2-4%. A sensitivity analysis and a correlation matrix are used to highlights the demand and the maximum available capacity as critical parameters. Results show that the most efficient machines (alternatively, the ones with highest available capacity) should be operated at maximum load while still striving for an efficient utilization of the exhaust gas.När elproduktionen från förnybara källor ökar krävs högre flexibilitet av fossil bränsleproduktion för att hantera fluktuationerna från sol- och vindkraft. Detta resulterar i kortare driftscykler och brantare ramper för turbinerna och mer osäkerhet för operatörerna. Detta avhandlingsarbete tillämpar matematisk optimering och statistisk inlärning för att förbättra det ekonomiska utnyttjandet av en kombicykel i ett kraftverk som består av två separata block med två gasturbiner och en ångturbin. Målet är att minimera bränsleförbrukningen hos gasturbinerna samtidigt som man tar hänsyn till en serie av villkor relaterade till efterfrågan som anläggningen står inför, kraftproduktionsbegränsningar etc. Detta uppnås genom skapandet av en matematisk modell för anläggningen som reglerar hur anläggningen kan fungera. Modellen är sedan optimerad för minsta möjliga bränsleförbrukning. Maskinteknik har använts på sensor data från själva anläggningen för att realistiskt simulera turbinernas beteende. In och utdata kurvor har erhållits för kraftproduktion och avgasvärmeproduktion med hjälp av ordinary least squares (OLS) med månads data och med en tio minuters samplingshastighet. Modellen är korsvaliderad och bevisad statistiskt giltig. Optimeringsproblemet formuleras genom en generaliserad disjunktiv programmering i form av ett mixed-integer linear problem (MILP) och löses med hjälp av en Branch-and-Bound algoritm. Resultatet från modellen är en veckas värden, med femton minuters intervall, totalt i två månader. Lägre bränsleförbrukning uppnås med hjälp av optimeringsmodellen, med en vecka minskad bränsleförbrukning i intervallet 2-4%. En känslighetsanalys och en korrelationsmatris används för att visa efterfrågan och den maximala tillgängliga kapaciteten som kritiska parametrar. Resultaten visar att de mest effektiva maskinerna (alternativt de med högsta tillgängliga kapacitet) bör drivas med maximal belastning medan de fortfarande strävar efter ett effektivt utnyttjande av avgaserna.
3
Errey, Olivia Claire. « Variable capture levels of carbon dioxide from natural gas combined cycle power plant with integrated post-combustion capture in low carbon electricity markets ». Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33240.
Texte intégralRésumé :
This work considers the value of flexible power provision from natural gas-fired combined cycle (NGCC) power plants operating post-combustion carbon dioxide (CO2) capture in low carbon electricity markets. Specifically, the work assesses the value of the flexibility gained by varying CO2 capture levels, thus the specific energy penalty of capture and the resultant power plant net electricity export. The potential value of this flexible operation is quantified under different electricity market scenarios, given the corresponding variations in electricity export and CO2 emissions. A quantified assessment of natural gas-fired power plant integrated with amine-based post-combustion capture and compression is attempted through the development of an Aspen Plus simulation. To enable evaluation of flexible operation, the simulation was developed with the facility to model off-design behaviour in the steam cycle, amine capture unit and CO2 compression train. The simulation is ultimately used to determine relationships between CO2 capture level and the total specific electricity output penalty (EOP) of capture for different plant configurations. Based on this relationship, a novel methodology for maximising net plant income by optimising the operating capture level is proposed and evaluated. This methodology provides an optimisation approach for power plant operators given electricity market stimuli, namely electricity prices, fuel prices, and carbon reduction incentives. The techno-economic implications of capture level optimisation are considered in three different low carbon electricity market case studies; 1) a CO2 price operating in parallel to wholesale electricity selling prices, 2) a proportional subsidy for low carbon electricity considered to be the fraction of plant electrical output equal to the capture level, and 3) a subsidy for low carbon electricity based upon a counterfactual for net plant CO2 emissions (similar to typical approaches for implementing an Emissions Performance Standard). The incentives for variable capture levels are assessed in each market study, with the value of optimum capture level operation quantified for both plant operators and to the wider electricity market. All market case studies indicate that variable capture is likely to increase plant revenue throughout the range of market prices considered. Different market approaches, however, lead to different valuation of flexible power provision and therefore different operating outcomes.
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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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Mishra, Brahmdatt. « Optimal operation of multiproduct batch plants ». [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=981974562.
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Zorzi, Luca <1987>. « Managing storage capacity and production set point for photovoltaic production plants ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2012. http://hdl.handle.net/10579/1961.
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The objective of this thesis is to realize an intelligent application that manages
renewable energy production plants with the capability of storing energy into
batteries, and in particular for the FIAMM Green Energy Island plant. Factors
to be taken into account are mainly: energy market prices, energy consumption
forecasting, energy production forecasting, state of charge of the batteries and
signals of the smart grid manager. At each interval the data is updated and
the model is veried, making the necessary modications to the power curve in
case of variations with respect to the forecasting maked in a previous time. The
application interacts with a SCADA system using a database.
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Dvorak, Gary John. « Economic analysis of irrigation pumping plants ». Thesis, Kansas State University, 1985. http://hdl.handle.net/2097/9834.
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Barrowman, Mary Ann McCullen. « Evaluation of operation plans using the Joint Theater Level Simulation ». Thesis, Monterey, California. Naval Postgraduate School, 1985. http://hdl.handle.net/10945/21317.
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Hong, Yoosun 1977. « The development of more effective operating plans for bus service ». Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/84840.
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Thesis (S.M. in Transportation)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.Includes bibliographical references (p. 114-115).
by Yoosun Hong.
S.M.in Transportation
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Ong, Chit Chung. « Operation Matador : Britain's war plans against the Japanese, 1918-1941 / ». Singapore : Times academic press, 1997. http://catalogue.bnf.fr/ark:/12148/cb37034998z.
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Crooks, Colin Andrew. « Synthesis of operating procedures for chemical plants ». Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/7795.
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Eftekhari, M. M. « Optimal operation of an air-conditioning plant ». Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234946.
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Tsang, Chi-fai Ringo, et 曾志輝. « Operation reengineering in a medium-sized plant ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31266848.
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Tsang, Chi-fai Ringo. « Operation reengineering in a medium-sized plant / ». Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B14708863.
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Benato, A. « Power plants behaviour during transient operating conditions ». Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3423908.
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System dynamic modelling and simulation is becoming a powerful and essential design tool. For this reason, this Ph.D. Thesis is devoted to analyse the transient operation conditions’ effects using power plant dynamic models.
In the first part of this dissertation, the dynamic analysis is the core of a procedure developed to predict lifetime reduction on traditional power plant devices. In particular, the plant dynamic model, and its capability of evaluating the trends of
the main thermodynamic parameters, which describe the plant operation during transient conditions, is the base point to identify the most stressed plant devices.
Being fundamental the role played by combined cycle power plants in the liberalized electricity market scenario, a combined cycle power plant is selected as test case. The dynamic model of a single pressure combined cycle power unit is built and the proposed procedure is tested. The results show that the procedure can be considered as a valuable innovative tool to assist power plant designers and operators in order to improve the plant’s flexibility without excessively compromising the integrity of devices subjected to high thermo-mechanical stresses.
The second part of this work underlines the essential role played by the dynamic analysis during the design phase of innovative small-medium size waste heat recovery units on isolated grid. In particular, after a design optimization process, the dynamic behaviour of gas turbines coupled with waste heat recovery units
(ORC, SRC and ABC power units) is tested to verify the grid stability and, in the case of an ORC unit, the working fluid thermochemical stability.
In conclusion, in this dissertation, two different software tools are proposed. In both cases the core is the plant dynamic model. The first tool is able to predict the plant thermodynamic variables and compute the components lifetime reduction
caused by load changes while the second one performs a design and optimization of different waste heat recovery units for stand-alone offshore facilities. The entire plant is then dynamically analysed in order to verify the grid stability and, in the
case of ORC unit, the working fluid thermochemical stability.La simulazione dinamica sta diventando uno strumento sempre più potente ed essenziale sia nella fase di design che durante il processo di ottimizzazione e gestione dei sistemi di produzione dell’energia. Da questa nuova necessità è nata l’idea di studiare gli effetti indotti dalle variazioni di carico sui componenti che costituiscono gli impianti energetici. A tal fine si devono sviluppare dei modelli di impianto in grado di simulare il comportamento dinamico del sistema in esame. Nella prima parte di questo elaborato, l’analisi dinamica è il cuore di una procedura integrata sviluppata allo scopo di prevedere la riduzione di vita utile dei componenti maggiormente sollecitati degli impianti termoelettrici. In particolare, il modello dinamico dell’impianto, capace di simulare l’andamento delle principali grandezze termodinamiche e quindi il comportamento del sistema durante le variazioni di carico, è l’elemento centrale della procedura poichè consente di identificare i componenti maggiormente soggetti a fenomeni di stress derivante da fatica termo-meccanica. Dato che gli impianti a ciclo combinato sono la tecnologia attualmente più efficiente e maggiormente diffusa tra i produttori di energia operanti nel mercato liberalizzato della produzione, il caso studio selezionato per testare la procedura sviluppata è proprio un impianto a ciclo combinato a singolo livello di pressione. I risultati ottenuti dimostrano che la procedura è un metodo innovativo in grado di assistere sia i progettisti che gli operatori degli impianti poiché in grado di simulare il comportamento dinamico del sistema e fornire indicazioni fondamentali sugli effetti indotti dall'esercizio flessibile. Tuttavia, l’analisi dinamica riveste un ruolo centrale anche nel caso di progettazione di impianti medio-piccoli di recupero del calore di scarto. Questi impianti vengono generalmente impiegati per incrementare le prestazioni del sistema e ridurre contestualmente i consumi di combustibile e le emissioni inquinanti rilasciate in atmosfera. La seconda parte di questo elaborato si focalizza quindi sull'utilizzo e l’integrazione dell’analisi dinamica nel processo di design e gestione degli impianti di piccola potenza inseriti in reti stand-alone di piattaforme oil and gas. In particolare, dopo l’individuazione del case study (impianto costituito da tre turbine a gas in ciclo semplice) ed una fase di studio delle possibili configurazioni (tre turbine a gas alternativamente affiancate da differenti sistemi di recupero: ABC, SRC, ORC), differenti tipologie di impianto sono state progettate utilizzando una ottimizzazione multi-obiettivo. A partire da questi dati di design, sono stati costruiti i modelli dinamici delle diverse configurazioni di impianto al fine di verificare la stabilità della rete elettrica e, nel caso di un sistema di recupero basato sulla tecnologia ORC, del fluido termovettore impiegato nel ciclo sottoposto. In conclusione, nella presente tesi di dottorato vengono sviluppati due differenti computer tools. In entrambi i casi il cuore è costituito dal modello dinamico dell’impianto di produzione dell’energia. Nel primo tool software è implementata una procedura innovativa sviluppata con lo scopo di simulare il comportamento dell’impianto durante le variazioni di carico, predire il trend delle principali grandezze termodinamiche, individuare i componenti maggiormente sollecitati e calcolare la riduzione di vita utile indotta sui componenti. Il secondo tool, invece, realizza prima una progettazione ottimizzata di differenti tipologie di unità di recupero del calore di scarto per stand-alone offshore facilities. Quindi, il comportamento dinamico dell’impianto viene simulato in maniera tale da verificare la stabilità della rete elettrica e, nel caso di una unità ORC, la stabilità termochimica del fluido operativo di ciclo.
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Han, L. Y. « Design strategy for flexible operation of process plant ». Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379242.
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Sohel, Mohammed Imroz. « Thermodynamic Modelling and Simulation for High Efficiency Design and Operation of Geothermal Power Plants ». Thesis, University of Canterbury. Mechanical Engineering, 2011. http://hdl.handle.net/10092/5292.
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This thesis analyses long term and short term environmental effects on geothermal power plant performance and discusses adaptive ways to improve performance. Mokai 1 geothermal power plant has been used as a case study for this investigation. Mokai 1 is a combined cycle plant where the binary cycles are air-cooled. The plant performance of an air-cooled binary cycle geothermal power plant is dependent on the environment (resource characteristics as well as weather conditions). For modelling such a power plant, two time scales are of interest: the yearly basis for aggregate plant performance for design and operations; and the daily basis for hourly plant performances for an accurate dispatch prediction.
Adaptive methodology for long term performance improvement has been introduced in this work which would save money and effort in the future by keeping the provisions to adapt to changes in resource characteristics based on geothermal reservoir modelling. The investigation was carried out using a steady state computer simulator of Mokai 1 geothermal power plant. The steady sate simulator was built specifically for this work. The deviation in performance of various components is less than 5% compared to the original plant design. The model is very generic and it can be used for other plants with simple adaptation or can be used for future plant design.
One of the main contributions of this work is an iterative method for modelling the environmental effect on short term performance on the air-cooled organic Rankine cycle. The ambient temperature is identified as the most influencing parameter on short term performance which influences the performance of the whole cycle in two ways. Firstly, by changing the equilibrium pressure inside the condenser, the turbine outlet pressure changes and hence, the turbine pressure ratio also changes. The turbine pressure ratio is a major parameter determining power generated by a turbine; therefore, the plant output is affected. Secondly, by changing the condenser outlet temperature with the ambient temperature, the pump inlet and outlet condition and consequently vaporizer equilibrium temperature and pressure are influenced. The developed method sought the equilibrium conditions of both condenser and vaporizer iteratively. In short, ORC cycle shifts on the T-s plane depending on the ambient temperature. This method iteratively seeks the shifted ORC on the T,s plane.
Two case studies have been carried out to demonstrate the method. The developed method shows robustness and converges exponentially. The model is effective for cycles that use saturated vapour as well as superheated vapour. The model essentially assumes steady state operation of the power cycle. The possible unit time where this model can be applied is bounded by the time required by a system to come into steady state. The saturated vapour cycle yielded average error 4.20% with maximum error 9.25% and the superheated vapour cycle yielded average error 2.12% with maximum error 5.60%. The main advantage of the developed method is that it requires a minimum number of inputs: condenser (p,T), vaporizer (p,T), condenser heat load, turbine efficiency (overall), pump work and the extremum conditions of all the components. These inputs should represent typical operating conditions of a plant. The model can predict the appropriate plant performance depending on the system heat input (geothermal fluid flow in this case) and the heat sink temperature. As the method is based on basic thermodynamics rather than empirical or semi-empirical approaches, this method is widely applicable. The main focus of this work is on the ORC but the developed method is applicable to any closed Rankine cycle. In addition, application of the developed iterative method to predict plant performance based on mean yearly weather data is also discussed in the thesis.
Water-augmented cooling system and optimization of plant operating point parameters have been proposed as adaptive measures to improve short term performance. Developed iterative method has been used for the short term performance analysis. The water-augmented cooling system is specifically suitable to mitigate the reduced power output during the summer. The simulated average gain in power during the summer (Jan, Feb, Nov and Dec) of an ORC of Mokai 1 geothermal power plant by incorporating a water-augmented cooling system was 2.3% and the average gain for the whole year was 1.6% based on the weather data of Taupo for the year 2005. A cost benefit analysis showed that water-augmented cooling system is more economical compared to other alternative renewable energies considered to meet summer peak demand. From the green house gas emissions perspective, water-augmented cooling is a better option than the gas fired peaking plants.
Adaptive approach for short term performance improvement by optimizing operating point parameters of an air-cooled binary cycle has huge potential with possible maximum improvement in power output by about 50%. The optimization takes in to account the effects of the geothermal resource characteristics and the weather conditions. The optimization is achieved by manipulating cycle mass flow rate and vaporizer equilibrium condition. Further study on the optimizing operating points to achieve improved short term performance has been recommended for future work.
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Ryman, Björn. « Den operativa samordningens problem ». Thesis, Försvarshögskolan, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:fhs:diva-5962.
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För att vinna ett krig med så få förluster som möjligt måste stridskrafterna samordnas inom ramen för en gemensam operation. Trots att det är det effektivaste sättet är det inte det enklaste. När stridskrafter sammanförs och samordnas på den operativa nivån, varvid mål, medel, metoder, tid och rum skall balanseras uppstår problem utifrån stridskrafternas särarter. Syftet med uppsatsen är att undersöka hur skillnaden i synen på samordning påverkar möjligheterna till samordning. Resultatet i uppsatsen visar att det är flygstridskrafterna som är den stridskraft som tydligast skiljer sig från övriga genom luftens natur stridskraftens egenskaper och synen på hur stridskraften skall användas inom ramen för den gemensamma operationen. Problem uppstår särskilt när det råder brist på resurser och för att den operativa nivån inte skall bli överflödig, måste det råda balans mellan mål, medel och metod på den operativa nivån.
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Rowlands, Rob. « How do we plan community ? : planning, housing and co-operative development ». Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/3789/.
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The focus of this PhD is on the way in which policy makers and practitioners ‘plan’ ‘community’ in the realisation of urban policies, particularly in housing and regeneration. The research underpinning this PhD took place against a policy backdrop of measures to increase the supply of (affordable) housing, to reduce social exclusion and to promote urban renaissance and sustainable communities. The common theme through all of the outputs has been focused on ‘community’ both as a entity which exists but which is difficult to define, and as an instrument of policy. The critical review presented here is in two distinct halves. The first half considers how community has been defined by policy makers and used as a tool in delivering better urban environments. As such it outlines how community has been commodified within policy, how through this commodification it is utilised through its active engagement in decision making, how it is physically planned via new housing developments and ultimately engages with questions as to whether community is lost through these moves. The second half of the review engages with discussions around mutualism. Drawing on research focused around co-operative and mutual housing it outlines how community exists organically and how this might be better understood if community is to be more successfully harnessed in urban and social policy. The review concludes by outlining areas for further research in taking this agenda forward.
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Georgiadis, Michael. « Advanced optimisation of batch plant design and operation ». Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/7394.
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Lakshmanan, Ramachandran. « Synthesis of operating procedures for complete chemical plants ». Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/14269.
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Mansoor, Sa'ad. « Behaviour and operation of pumped storage hydro plants ». Thesis, Bangor University, 2000. https://research.bangor.ac.uk/portal/en/theses/behaviour-and-operation-of-pumped-storage-hydro-plants(c1905e46-af51-444a-b85b-f2ee7ad1b598).html.
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The thesis describes the development of a generic nonlinear computer model of a pumped storage hydroelectric scheme. The model combines the hydraulic, electrical and control systems. In particular, this model includes the water hammer effects, the hydraulic coupling in the common water supply tunnel, the power system stiffness and the electrical coupling between the generator and the power system. The benefit of the simulation is that it gives insight into the plant characteristics and improves understanding of the physical phenomena involved. A specific case of the model for Dinorwig power station is tested against the plant responses and establishes a good degree of confidence in the simulation. The model is used to evaluate governor performance and establish stability boundaries for various operating conditions. The model is also used to design a new black-start regime which allows Dinorwig to energise the power system after blackout, with individual units picking up incremental loads up to 15% of machine rating while ensuring that frequency deviations remains within limits. Another application of the model is to explain why a period of sustained power oscillation occurred at Dinorwig and to identify under what circumstances this can take place. Linearised system models are used for governor tuning and root locus and Bode plot methods applied to establish the optimum governor settings for different operation conditions. The results demonstrate the significance of hydraulic coupling and the power system (grid) size on governor tuning. The final part of the work addresses conversion of the model to run in real-time and interfacing it with an actual unit governor. The results demonstrate the practicality of the hardware-in-the-loop simulation as a technique for safely implementing and testing new controllers or enhancements to the current controller.
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Zhao, Yongjun. « An Integrated Framework for Gas Turbine Based Power Plant Operational Modeling and Optimization ». Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/10580.
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The deregulation of the electric power market introduced a strong element of competition. Power plant operators strive to develop advanced operational strategies to maximize the profitability in the dynamic electric power market. New methodologies for gas turbine power plant operational modeling and optimization are needed for power plant operation to enhance operational decision making, and therefore to maximize power plant profitability by reducing operations and maintenance cost and increasing revenue.
In this study, a profit based, lifecycle oriented, and unit specific methodology for gas turbine based power plant operational modeling was developed, with the power plant performance, reliability, maintenance, and market dynamics considered simultaneously. The generic methodology is applicable for a variety of optimization problems, and several applications for operational optimization were implemented using this method.
A multiple time-scale method was developed for gas turbine power plants long term generation scheduling. This multiple time-scale approach allows combining the detailed granularity of the day-to-day operations with global (seasonal) trends, while keeping the resulting optimization model relatively compact. Using the multiple timescale optimization method, a profit based outage departure planning method was developed, and the key factors for this profit based approach include power plant aging, performance degradation, reliability deterioration, and the energy market dynamics. A novel approach for gas turbine based power plant sequential preventive maintenance scheduling was also introduced. Finally, methods to evaluate the impact of upgrade packages on gas turbine power plant performance, reliability, and economics were developed, and TIES methodology was applied for effective evaluation and selection of gas turbine power plant upgrade packages.
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Spelling, James. « Steam Turbine Optimisation for Solar Thermal Power Plant Operation ». Licentiate thesis, KTH, Kraft- och värmeteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-35386.
Texte intégralRésumé :
The provision of a sustainable energy supply is one of the most important issues facing humanity at the current time, given the strong dependence of social and economic prosperity on the availability of affordable energy and the growing environmental concerns about its production. Solar thermal power has established itself as a viable source of renewable power, capable of generating electricity at some of the most economically attractive rates. Solar thermal power plants are based largely on conventional Rankine-cycle power generation equipment, reducing the technological risk involved in the initial investment. Nevertheless, due to the variable nature of the solar supply, this equipment is subjected to a greater range of operating conditions than would be the case in conventional systems. The necessity of maintaining the operational life of the steam-turbines places limits on the speed at which they can be started once the solar supply becomes available. However, in order to harvest as much as possible of the Sun’s energy, the turbines should be started as quickly as is possible. The limiting factor in start-up speed being the temperature of the metal within the turbines before start-up, methods have been studied to keep the turbines as warm as possible during idle-periods. A detailed model of the steam-turbines in a solar thermal power plant has been elaborated and validated against experimental data from an existing power plant. A dynamic system model of the remainder of the plant has also been developed in order to provide input to the steam-turbine model. Three modifications that could potentially maintain the internal temperature of the steam-turbines have been analysed: installation of additional insulation, increasing the temperature of the gland steam and use of external heating blankets. A combination of heat blankets and gland steam temperature increase was shown to be the most effective, with increases in electricity production of up to 3% predicted on an annual basis through increased availability of the solar power plant.Hållbar energiförsörjning är för närvarande en av de viktigaste frågorna för mänskligheten. Socialt och ekonomiskt välstånd är starkt kopplat till rimliga energipriser och hållbar energiproduktion. Koncentrerad solenergi är nu etablerad som en tillförlitlig källa av förnybar energi och är också ett ekonomiskt attraktivt alternativ. Koncentrerade solenergikraftverk bygger till stor del på konventionella Rankine-cykel elgeneratorer, vilka minskar de tekniskt relaterade riskerna i den initiala investeringen. På grund av solstrålningens skiftande karaktär utsätts denna utrustning för mer varierade driftsförhållanden, jämfört med konventionella system. Behovet av att bibehålla den operativa livslängden på ångturbiner sätter gränser för uppstartshastigheten. För att utnyttja så mycket som möjligt av solens energi bör ångturbinen startas så snabbt som möjligt när solstrålningen blir tillgänglig. Eftersom temperaturen i metalldelar hos turbinerna är den begränsande faktorn, har metoder studerats för att hålla turbinerna så varma som möjligt under tomgångsperioder. En detaljerad modell av ångturbiner i ett solenergikraftverk har utvecklats och validerats mot experimentella data från ett befintligt kraftverk. En dynamisk systemmodell av de övriga delarna av anläggningen har också utvecklats för att ge input till ångturbinsmodellen. Tre modifieringar som potentiellt kan bidra till att upprätthålla den inre temperaturen i ångturbiner har analyserats: montering av ytterligare isolering, ökning av temperaturen hos glänsångan och användning av elvärmefiltar. En kombination av elvärmefiltar och en temperaturökning av glänsångan visade sig vara det mest effektiva alternativet. Åtgärderna resulterade i en ökad elproduktion på upp till 3%, beräknat på årsbasis genom ökad tillgänglighet hos kraftverket.
QC 20110629
TURBOKRAFT
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Chukanova, E. « Modelling of screw compressor plant operation under intermittent conditions ». Thesis, City, University of London, 2016. http://openaccess.city.ac.uk/15825/.
Texte intégralRésumé :
Compressor plant frequently operates under unsteady conditions. This is due to pressure fluctuations, variable flow demand, or unsteady inlet conditions, as well as shaft speed variation. Also, following demand, compressor plants often work intermittently with frequent starts and stops. This may cause premature wear, decrease of compressor performance and even failure, which might cost millions of pounds to industry in downtime. However, there is still a lack of published data which describes intermittent plant behaviour, or predicts the effects of unsteady operation upon compressor plant performance. Thus, there appears to be a need to develop a mathematical model to calculate compressor plant performance during intermittent operating conditions and to verify this model with experimental data. Accordingly, this thesis describes an experimental and analytical study of screw compressor plant operating under unsteady conditions. For this purpose a one-dimensional model of the processes within a compressor was used, based on the differential equations of conservation of mass and energy, extended to include other plant components, such as storage tanks, control valves and connecting pipes. The model can simulate processes in both oil-free and oil-injected compressor plants during transient operation, including the effects of sudden changes in pressure, speed and valve area. Performance predictions obtained from the model gave good agreement with test results. This model can, therefore, be used to predict a variety of events, which may occur in everyday compressor plant operation.
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McHenry, Robert Sean. « Nuclear power plant surveillance issues for extended operating cycles ». Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43343.
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Williams, Christopher Michael S. M. Massachusetts Institute of Technology. « The effects of variable operation on RO plant performance ». Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68958.
Texte intégralRésumé :
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 113-117).
Optimizations of reverse osmosis (RO) plants typically consider steady state operation of the plant. RO plants are subject to transient factors that may make it beneficial to produce more water at one time than at another. These factors can impact the optimal size of the plant. The electricity price is one factor of importance. When long periods of time are considered, other factors such as weather and seasonal water demand can influence the operation and size as well. With long-term operation, water storage is possibile. This thesis investigates the optimal time-varying operation and size of a single stage RO plant subject to a time-varying electricity price. A single stage RO model is modified to include a variable plant size controlled by the number of modules. The annual capital and operating expenses of the plant are calculated in an RO economics sub-model. In one study, the short-term (single day) operation and design are optimized to minimize the total annualized cost of the plant. The operation and size are optimized for four different electricity price functions: constant, moderately fluctuating, highly fluctuating, and actual electricity prices. The results show that significant savings (1-7%) are obtainable and optimal oversizing of 15% is chosen for the fluctuating electricity price functions considered therein. The plant produces more water when electricity is cheap, and shuts off during periods of high electricity price when oversized. The size and day-by-day operation are optimized for one year subject to Spain's electricity price. Little savings and oversizing are obtainable for the day-by-day optimization due to low fluctuations in the electricity price during the year. In a second study, the long-term (one year) operation with storage of product water is optimized to minimize the cumulative cost of reclaiming the water from the reservoir and/or of the electricity. The operation is optimized for electricity prices for California, Cyprus, Greece and Spain for 2010. Low savings are obtained with variable operation. Shutting off is not chosen in the optimal operation and 1% oversizing typically leads to increased costs. Lower electricity prices with more fluctuations result in better savings. Product water is stored during the winter.
by Christopher Michael Williams.
S.M.
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Chittratanawat, Sarawoot. « Operation based facilities design / ». free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3025611.
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Chen, Hongmei. « A Multiscale Forecasting Methodology for Power Plant Fleet Management ». Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6849.
Texte intégralRésumé :
In recent years the electric power industry has been challenged by a high level of uncertainty and volatility brought on by deregulation and globalization. A power producer must minimize the life cycle cost while meeting stringent safety and regulatory requirements and fulfilling customer demand for high reliability. Therefore, to achieve true system excellence, a more sophisticated system-level decision-making process with a more accurate forecasting support system to manage diverse and often widely dispersed generation units as a single, easily scaled and deployed fleet system in order to fully utilize the critical assets of a power producer has been created as a response.
The process takes into account the time horizon for each of the major decision actions taken in a power plant and develops methods for information sharing between them. These decisions are highly interrelated and no optimal operation can be achieved without sharing information in the overall process.
The process includes a forecasting system to provide information for planning for uncertainty. A new forecasting method is proposed, which utilizes a synergy of several modeling techniques properly combined at different time-scales of the forecasting objects. It can not only take advantages of the abundant historical data but also take into account the impact of pertinent driving forces from the external business environment to achieve more accurate forecasting results.
Then block bootstrap is utilized to measure the bias in the estimate of the expected life cycle cost which will actually be needed to drive the business for a power plant in the long run. Finally, scenario analysis is used to provide a composite picture of future developments for decision making or strategic planning.
The decision-making process is applied to a typical power producer chosen to represent challenging customer demand during high-demand periods. The process enhances system excellence by providing more accurate market information, evaluating the impact of external business environment, and considering cross-scale interactions between decision actions. Along with this process, system operation strategies, maintenance schedules, and capacity expansion plans that guide the operation of the power plant are optimally identified, and the total life cycle costs are estimated.
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Layme, Ventura Leonardo Teofilo. « Diseño de un Plan de Reingeniería de Procesos para el Área Operativa del Taller Automotriz E&E - Arequipa ». Bachelor's thesis, Universidad Continental, 2018. http://repositorio.continental.edu.pe/handle/continental/5180.
Texte intégralRésumé :
El objetivo principal del Trabajo de Investigación fue proponer el “Diseño de un Plan de Reingeniería de Procesos para el Área Operativa del Taller Automotriz E&E”, que pueda dar solución al problema de desorden y desorganización que existe en el área Operativa, la cual genera retrasos en el tiempo de entrega del servicio de mantenimiento, acarreando la insatisfacción de los clientes por la demora en el proceso.
Esta mejora de ha evaluado bajo la Metodología 5s la cual nos permitirá optimizar los procesos al aplicar el enfoque de operaciones esbeltas.
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Malikova, Alexandra A. « MBTA Green Line 3-car train operating plans to enhance capacity and reliability ». Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74271.
Texte intégralRésumé :
Thesis (S.M. in Transportation)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 147-149).
Transit agencies face a variety of challenges, from increasing ridership to changes in infrastructure, to system expansions, all of which require significant preparation to accommodate the changes without affecting passengers or the agency negatively. The MBTA Green Line, a Boston light rail system serving nearly 230,000 average weekday passengers, will be undergoing major changes in the next two decades, including nearly doubling of ridership and system expansion. In order to prepare for these changes, measures need to be taken to increase capacity and plan for operations on the new segment. Starting in Fall 2010, the MBTA added to a 2-car train operation, and subsequently increased, a number of 3-car trains on three of the four Green Line branches, in order to begin to address the capacity issue. This thesis analyzes service performance before and after implementation of 3-car trains to find that although scheduled capacity increased slightly, the actual capacity of the system remained constant during the morning peak period and decreased during the evening peak period. Furthermore, there were some negative impacts with respect to passenger waiting time and running times, thus worsening the overall passenger experience. However, since 3-car trains will be required for increasing capacity on the Green Line, it is recommended that trials of 3-car trains continue, with the restriction that only 2- or 3-car trains operate on a branch. Furthermore, field observations at terminal stations on two of the branches show differences in operations management practices, which help explain some variability in service along the route, and point to strategies to improve service reliability.
by Alexandra A. Malikova.
S.M.in Transportation
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Duffy, Gerrad. « OCTOGRAPH : A Methodology for Returning the Industrial Plant to the Desired Operating Point ». Thesis, Griffith University, 2018. http://hdl.handle.net/10072/377652.
Texte intégralRésumé :
The performance of a processing plant can be measured in many ways, whether it be production throughput, product quality within contract specifications or cost per tonne margins which may extend to process energy consumption (electrical or steam), equipment maintenance or failure or resourcing costs. A processing plant can be a complex process with multiple control schemes ranging from simple control to advanced control such as supervisory schemes, incorporating estimation and optimization techniques. Each processing plant operates to specific process objectives often represented by a target operating point.
Often, after some years of plant operation the operating point has drifted from the target. Before the processing plant is returned to the target operating point and its performance re-tuned, the performance of the control schemes must be understood and areas for improvement identified.
This research proposes a methodology named OCTOGRAPH, that assesses the control scheme performance of the industrial plant, identifying control loops for improvement and control strategies to be implemented. The aim of the methodology is to improve the performance of the industrial plant, returning the operating point to the desired target.
This thesis has developed an extension to the Harris Index capable of providing control practitioners with both, the paradigm and a practical tool to assess the current state of the control schemes within the industrial setting with no impact on production and no requirement for a priori knowledge of the control scheme or process dynamics. The developed performance assessment paradigm also provides guidance to improvement areas with a plant-wide process improvement focus.
The results conclude that a mineral processing plant operating point does drift from the nominated operating set point. By firstly assessing the mineral processing plant with a closed loop control performance assessment technique with a focus on the plant-wide interactions, the plants control performance is calculated. The challenge then is to determine how to improve the performance of the plant to return the plant to the nominal operating point. The OCTOGRAPH methodology presented describes the interconnections between each of the process and manipulated variables in the form of a dead time relationship. By connecting the process variables in the shortest path, constructing a control strategy improves the plant performance.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text
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Carvajal, Cortés Hernán. « Centro operativo nacional cruz roja chilena ». Tesis, Universidad de Chile, 2006. http://www.repositorio.uchile.cl/handle/2250/100802.
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Cornejo, Herrero Alexander, Sterling Robert Godoy et Gutierrez Lilyan Leyva. « Plan estratétigo y operativo para el lanzamiento del producto Aprovel Plus ». Master's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2000. http://hdl.handle.net/10757/650398.
Texte intégralRésumé :
Se ha observado que el mercado peruano de la hipertensión arterial representa el 46.37% del mercado cardiovascular con un crecimiento del 11% entre el año 1998 y 1999, debido principalmente al estresante ritmo de vida que se vive en la actualidad y a la mayor conciencia que están tomando las personas con respecto a esta enfermedad.Tesis
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Gonzalez, Robert. « Optimal design, scheduling and operation of pipeless batch chemical plants ». Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/11102.
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Amba, Harsha Vardhan. « Operation and Monitoring of Parabolic Trough Concentrated Solar Power Plant ». Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5891.
Texte intégralRésumé :
The majority of the power generated today is produced using fossil fuels,emitting carbon dioxide and other pollutants every second. Also, fossil fuels will eventually run out. For the increasing worldwide energy demand, the use f reliable and environmentally beneficial natural energy sources is one of the biggest challenges. Alongside wind and water, the solar energy which is clean, CO2-neutral and limitless, is our most valuable resource.
Concentrated solar power (CSP) is becoming one of the excellent alternative sources for the power industry. The successful implementation of this technology requires the efficient design of tracking and operation system of the CSP solar plants. A detailed analysis of components needed for the design of cost-effective and optimum tracker for CSP solar systems is required for the power plant modeling, which is the primary subject of this thesis. A comprehensive tracking and operating system of a parabolic trough solar power plant was developed focusing primarily on obtaining optimum and cost effective design through the simplified methodology of this work. This new model was implemented for a 50 kWe parabolic trough solar power plant at University of South Florida, Tampa.
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Gustafsson, Martin. « Improved Governing of Kaplan Turbine Hydropower Plants Operating Island Grids ». Thesis, KTH, Reglerteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-125805.
Texte intégralRésumé :
To reduce the consequences of a major fault in the electric power grid, functioning parts of the grid can be divided into smaller grid islands. The grid islands are operated isolated from the power network, which places new demands on a faster frequency regulation. This thesis investigates a Kaplan turbine hydropower plant operating an island grid. The Kaplan turbine has two control signals, the wicket gate and the turbine blade positions, controlling the mechanical power. The inputs are combined to achieve maximum turbine efficiency at all operating points. In relative terms, the wicket gate has a fast dynamic but small effect on the mechanical power, while the turbine blade has slow dynamic and large effect on the output, seen around an operating point. The proposed method to get a faster frequency control uses a different combination of the turbine inputs, transferring control effect from the turbine blades to the wicket gates at the cost of loss of turbine efficiency. The method is investigated with time domain simulations on a model containing all essential parts of a Kaplan turbine hydropower plant.
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Streckienė, Giedrė. « Research of Heat Storage Tank Operation Modes in Cogeneration Plant ». Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110621_170138-31454.
Texte intégralRésumé :
The dissertation investigates typical operation modes of the heat storage tank in the small-scale cogeneration (CHP) plant, analyses formation of thermal stratifi-cation in such storage tank and presents the simulation of the stratification. The main aim of the dissertation is to investigate peculiarities of operation modes of heat storage tank in small-scale CHP plant, develop an algorithm allowing to choose the storage tank volume and present a model allowing determination of thermal stratification in the storage tank at any time of its operation.Disertacijoje nagrinėjami būdingi šilumos akumuliacinės talpos veikimo režimai, susiformuojantys nedidelės galios kogeneracinėje jėgainėje, tiriamas šiluminės stratifikacijos susidarymas tokioje talpoje ir atliekamas jos modeliavimas. Pagrindinis disertacijos tikslas – ištirti nedidelės galios kogeneracinės jėgainės šilumos akumuliacinės talpos veikimo režimų ypatumus, sudaryti algoritmą, padedantį parinkti tokios talpos tūrį ir pateikti modelį, leidžiantį nustatyti šiluminę stratifikaciją akumuliacinėje talpoje bet kuriuo jos veikimo metu.
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Prasad, Girijesh. « Performance monitoring and control for economical fossil power plant operation ». Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264537.
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Gillie, Mary. « Operation and regulation of a 'virtual wind/gas' power plant ». Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405322.
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Aryana, Shahla. « Advanced operation and optimisation of an industrial ethylene oxide plant ». Connect to full text, 2008. http://ses.library.usyd.edu.au/handle/2123/5402.
Texte intégralRésumé :
Thesis (Ph. D.)--University of Sydney, 2009.Includes graphs and tables. Title from title screen (viewed November 06, 2009). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Engineering and Information Technologies. Degree awarded 2009; thesis submitted 2008. Includes bibliographical references. Also available in print form.
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Aryana, Shahla. « Advanced operation and optimisation of an industrial ethylene oxide plant ». Phd thesis, Faculty of Engineering and Information Technologies, 2009. http://hdl.handle.net/2123/5402.
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Do, Tung Van. « Optimal operation of a hydroelectric reservoir ». Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26694.
Texte intégralRésumé :
This thesis examines the influence of different degrees of serial correlation in the streamflow records on optimal operation of a hydroelectric reservoir. This thesis also investigates the practical aspects of choosing different decision variables, considering effects on ease of implementation, total benefit, and actual use for real-time operations.
Stochastic dynamic programming was used to optimize the long-term operation of a hydroelectric project with a single reservoir. Reservoir inflows were analyzed using monthly flow record for 58 years with the assumption that monthly inflows are either perfectly correlated, uncorrelated, or partially correlated. Reservoir level change and powerhouse discharge were considered as alternative decision variables for each of the three cases of inflow serial correlation. The optimization results were then examined and compared to determine the significance of the choice of decision variables and to explore the effects of inflow serial correlation on practical operating decisions which might be based on the results of the optimization.
It was found that (1) Case 2 in which inflows were assumed perfectly correlated and Case 3 with partially correlated inflows produce, respectively, highest and lowest total expected return, (2) the difference in total expected return between cases depends largely upon the physical characteristics of the system, (3) the reservoir level change decision case produces more conservative results than the discharge decision case, (4) the results from the reservoir level change decision are easier to use for realtime operation than those from the discharge decision case, (5) different results will be produced with different choice of decision variables.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Fredrik, Bolin, et Lindgren Andreas. « Först på plats : En studie kring förstahandsåtgärder bland poliser i yttre tjänst ». Thesis, Umeå University, Basic training programme for Police Officers, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-27344.
Texte intégralRésumé :
I den här studien har vi tittat på hur utbildning, motivation och feedback påverkar arbetsprestationen hos ordningspoliser, men vi har även tittat på hur dessa faktorer påverkar varandra. En av frågeställningarna i arbetet har varit om en handdator med lathundar/checklistor skulle kunna vara ett bra arbetsredskap i polisarbetet, samt hur denna handdator skulle kunna påverka arbetsprestationen ur ett utbildnings-, motivations- och feedbackperspektiv. Vi har inte på något sätt skrivit en heltäckande studie över vad som påverkar dessa faktorer utan koncentrerat oss på hur en handdator skulle kunna fungera motiverande, utbildande och som en källa för feedback av det egna arbetet. Vår slutsats har blivit att vi tror att en handdator skulle kunna höja arbetsprestationen hos poliser i yttre tjänst som helhet och att vissa poliser skulle kunna få en ökad arbetskapacitet av att jobba med ett sådant hjälpmedel. Det finns dock många ytterliggare faktorer som påverkar som vi har utelämnat eller bara berört lätt i denna studie.
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Panahi, Mehdi. « Plantwide Control for Economically Optimal Operation of Chemical Plants : - Applications to GTL plants and CO2 capturing processes ». Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemisk prosessteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-15210.
Texte intégralRésumé :
In this thesis, the systematic plantwide procedure of Skogestad (2004) is applied to two processes; 1- Post-combustion CO2 capturing processes, 2- Natural gas to liquid hydrocarbons (GTL) plants, in order to design economically efficient control structures, which keep the processes nearoptimum when disturbances occur. Because of the large magnitude of energy consumption in both these processes, optimal operation is of great importance. The self-optimizing concept, which is the heart of the plantwide procedure is used to select the right controlled variables in different operational regions, which when they are kept constant, indirectly give the operation close to optimum. The optimal is to reconfigure the self-optimizing control loops when the process is entered into a new active constraint region, but we try to arrive at a simple/single control structure, which does not need switching, where a reasonable loss in operating economic objective function is accepted. The CO2 capturing process studied here is an amine absorption/stripping system. The chosen objective function for this process is first to minimize the energy requirement while fixed CO2 recovery of 90% is met. This leads to one unconstrained degree of freedom. Maximum gain rule is applied and a temperature close to the top of the stripper is found as the best controlled variable. Further, we introduce penalty on CO2 amount released to the atmosphere, and this results in two unconstrained degrees of freedom. CO2 recovery and a temperature close to the top of the stripper are found as the best individual controlled variables in low feedrate. In higher flue gas flowrates, stripper heat input saturates and the self-optimizing method is repeated to select the right controlled variable for the remaining degree of freedom. We validate the propose control structures using dynamic simulations, where 5 different alternatives including decentralized control loops and multivariable controller are studied. We finally achieve a simple control structure, which handles a wide range of change in throughput and keeps the process close to optimum without the need for switching the control loops or updating the controlled variables setpoints by a costly real time optimizer. The GTL process modeled in this thesis includes an auto-thermal reformer (ATR) for synthesis gas production and a slurry bubble column reactor (SBCR) for the Fischer-Tropsch (FT) reactions. The FT products distribution is determined using a well-known Anderson- Schultz- Flory (ASF) model, where carbon component in CO (consumption rate is found based on the proposed rate by Iglesia et al.) is distributed to a range of hydrocarbons. ASF is a function of chain growth probability and the chain growth is a function of H2/CO ratio. We study different scenarios for chain growth and we arrive at a suitable model for optimal operation studies. The optimal operation is considered in two modes of operation. In mode I, natural gas feedrate is assumed given and in mode II, natural gas feedrate is also a degree of freedom. After optimization, in both modes, there are three unconstrained degrees of freedom. The best individual self-optimizing controlled variables are found and since the worst-case loss value is rather notable, combination of measurements is done, which reduces the loss significantly. Mode II happens when oxygen flowrate capacity reaches the maximum and we show that operation in mode II in this case is in snowballing region where operation should be avoided. Operation at maximum oxygen flowrate capacity is where maximum practical profit can be achieved.
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Graftiaux, Alain. « Resultats a l'age adulte de l'intervention dite de cavalier proposee pour la correction des pieds plats de l'enfant ». Université Louis Pasteur (Strasbourg) (1971-2008), 1989. http://www.theses.fr/1989STR1M118.
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Akpan, Patrick Udeme-Obong. « Impact on heat rate and subsequent emissions due to varying operation of coal fired power plants ». Doctoral thesis, Faculty of Engineering and the Built Environment, 2019. https://hdl.handle.net/11427/31647.
Texte intégralRésumé :
Energy mix modellers often use a constant emissions factor model, which more or less implies a constant heat rate, when trying to show the emissions reduction benefits of integrating renewable power generation system on the grid. This approach does not consider the fact that there is a deterioration in the heat rate with load for the Coal Fired Power Plants that need to accommodate the additional renewable supply. If varying heat rate were to be included in a study, it is often limited to plant specific cases. This PhD presents a novel Variable Turbine Cycle Heat Rate (V-TCHR) model for predicting the part load Turbine cycle heat rate (TCHR) response of various Coal Fired Power Plant (CFPP) architectures, without detail knowledge of the entire steam cycle parameters. A total of 192 process models of representative CFPP architectures were developed using a Virtual Plant software. The models had different combinations of the degree of reheat; the throttle temperature; throttle pressure; and condenser cooling technology. The part load response of all the models were simulated using the software.
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Aragüés, Peñalba Mònica. « Operation and control of transmission systems for offshore wind power plants ». Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/393893.
Texte intégralRésumé :
This thesis deals with grid integration of oshore wind power plants through HVDC (High Voltage Direct Current) or HVAC (High Voltage Alternating Current) transmission . The behaviour of wind farms and their transmission systems in normal operation and under faults is analyzed. On the eld of HVDC transmission , a control scheme based on an optimum voltage algorithm is proposed and compared to voltage droop control. The dierences between the proposed scheme and droop control in terms of losses are analyzed, in steady state as well as dynamically. This new control scheme is enhanced, being able to perform secondary and tertiary control strategies simultaneously for DC grids. Concerning HVAC transmission, the operation of AC connected wind power plants equipped with full power converter wind turbines is analyzed under deep voltage sags on the main AC grid.
Standard control schemes, based on the strict application of grid codes, can lead to instability problems when this kind of severe disturbances occurs. A coordinated control scheme is proposed to operate the system, ensuring fault ride through capability. An index alerts of instability proximity and allows to actívate active power and reactive power regulation to guarantee safe operation during faults. For enabling the optimal operation of transmission systems, an optimal power flow tool is described for hybrid HVDC-HVAC systems, for different objective functions. This tool is tested in a scaled platform. Finally, the secure and optimal operation of these systems is analysed for a scenario with high penetration of oshore wind, proposing a methodology to evaluate the cost of operation and wind energy curtailed.La present tesi tracta la integració a xarxa de plantes eòliques marines a través de transmissió en HVDC (Alta Tensió en Corrent Continu) o HVAC (Alta Tensió en Corrent Altern). S'analitza el comportament dels parcs eòlics i del seus sistemes de transmissió en condicions normal i en situacions de pertorbacions elèctriques. En el camp de l'HVDC, es descriu un esquema de control basat en un algorisme de tensions òptimes i es compara amb el control de tensió droop. Les diferències entre l'esquema de control proposat i el droop s'analitzen, des del punt de vista de pèrdues, en estat estacionari i dinàmicament. L'esquema de control proposat es millora, oferint la possibilitat de realitzar estratègies de control secundari i terciari en xarxes DC. Dins de la transmissió en l'HVAC, s'analitza l’operació de parcs eòlics equipats amb convertidors de plena potència quan s'esdevenen sots profunds a la xarxa AC. Els esquemes de control estàndards, basats en l’aplicació estricta dels requisits de connexió, poden comportar problemes d'estabilitat transitòria quan s'esdevenen pertorbacions severes. Es proposa un esquema de control coordinat per operar el sistema, assegurant el fault ride through. Un índex alerta de a de la proximitat d'una inestabilitat i permet activar la regulació de potencia activa i reactiva per assegurar l’operació segura durant la falta. Tenint en compte que l’expansió del sistema de transmissió presenta tant enllaços HVDC com HVAC, es desenvolupa una eina per determinar fluxos de potencia òptims en xarxes híbrides HVDC-HVAC, per diferents funcions objectiu. Es realitzen proves experimentals en una plataforma de baixa tensió per comprovar el funcionament d'aquesta eina. Finalment, s'estudia l’operació òptima i segura d'aquests sistemes, per un escenari amb gran penetració d'energia eòlica, proposant una metodologia per avaluar el cost d’operació i la reducció d'energia eòlica produïda.
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Schönleber, Kevin. « Control and operation of wind power plants connected to DC grids ». Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/462246.
Texte intégralRésumé :
Remote offshore wind power plants (WPPs) are being linked through high-voltage de voltage-source converter (VSC-HVdc) transmission to the main grids. The current deployments of HVdc grid connections for offshore WPPs are point-to-point transmission systems. Moreover, WPPs connected to the offshore VSC-HVdc form an offshore ac grid which operates non synchronously to the main grids. lt is characterized by extensive submarine cabling and, in the case offull-scale power converter-based wind turbines, by being purely converter-based.
This thesis goes into two main aspects regarding the operation of HVdc-connected WPPs: i) reactive power and voltage control and ii) fault ride through (FRT) in the ac offshore grids. Optimization-based reactive power control strategies are enhanced to the application of an ac grid consisting ofone grid-forming and several grid-connected converters. A reactive power and voltage control method is introduced which aims to increase the annual energy production from a single WPP. In the industrial application, several WPPs might be clustered which leads to multi-layered controllers and operation boundaries. Taking this into account, an operation strategy with reasonable communication requirements is suggested and evaluated against conventional methods .
The work further propases a control framework for the grid-form ing offshore VSC-HVdc. Special emphasis is put on the FRT of unbalanced faults in the offshore grid and the provision of controlled currents for ease of fault detection. Furthermore, the internal variables of the offshore modular multi-level VSC-HVdc are analyzed. Moreover, tour FRT strategies for the grid connected converters are evaluated for unbalanced faults in the offshore grid. This consequently implies that control strategies in symmetrical components are considered. Furthermore, the reduction of over-modulation and over-voltages by the power converters in the offshore grid is dealt with.Los parques eólicos marinos suelen conectarse a redes eléctricas terrestres a través de corriente continua de alta tensión (siglas en inglés: HVdc) utilizando convertidores de fuente de tensión (siglas en inglés: VSC) cuando la corriente alterna de alta tensión (siglas en inglés: HVac) resulta tecnológicamente e económicamente desfavorable. Los parques eólicos conectados al convertidor HVdc marino crean redes eléctricos marinas de corriente alterna que operan asíncronamente a las redes terrestres. Dichas redes se caracterizan por tener cables submarinos, y, en el caso de aerogeneradores con convertidores de plena potencia, resultan en redes constituidas únicamente por convertidores de potencia. Esta tesis investiga dos de los aspectos principales de la operación de parques eólicos marinos conectados en corriente continua de alta tensión: i) la regulación de potencia reactiva y tensión y ii) la operación durante faltas eléctricas en las redes marinas. Se han propuesto estrategias de optimización del control de reactiva para su aplicación a una red ac con varios convertidores conectados. Se ha introducido un método de regulación de potencia reactiva y tensión cuyo objetivo es incrementar la generación eléctrica del parque eólico. En la implementación práctica, varios parques eólicos podrían pertenecer a la misma red lo cual conduce a reguladores multicapas y a la consideración las interfaces entre los operadores. Teniendo esto en cuenta, se propone una estrategia de regulación de potencia reactiva asumiendo unos tiempos de comunicación razonables, y se compara a conceptos convencionales. La segunda parte de la tesis sugiere un método de control para el convertidor marino en secuencia directa e inversa. Está diseñado para la operación normal y la operación durante faltas asimétricas y permite la inyección de corrientes reguladas para la detección de la falta. Además, se analizan las variables internas del convertidor modular multinivel (siglas en inglés: MMC) en estas situaciones. Asimismo, se han evaluado cuatro estrategias de respuesta a faltas asimétricas por parte de los convertidores de los aerogeneradores. Estas estrategias también incluyen el control en secuencia directa e inversa. Finalmente, se investiga la reducción de sobremodulación en los convertidores y sobretensiones en la red marina.
Hochspannungs–Gleichstrom–Übertragung (HGÜ) stellt eine effiziente Lösung zur Netzanbindung weit entfernter Offshore–Windkraftanlagen dar. Die derzeit verwendeten Punkt–zu–Punkt–Anbindungen basieren dabei auf spannungsgeführten Umrichtertopologien. Das seeseitige Wechselstromnetz verbindet die Windkraftanlagen mit der netzbildenden HGÜ–Umrichterstation. Es charakterisiert sich im Vergleich zu gewöhnlichen Netzen durch das ausschließliche Verwenden von Seekabeln und, im Fall einer Verwendung von Windkraftanlagen mit Vollumrichtern, durch das Fehlen gewöhnlicher, direkt gekoppelter Synchrongeneratoren. Die vorliegende Dissertation behandelt zwei Kernaspekte bezüglich dem Betrieb HGÜ–angebundener Windparks: i) die kontinuierliche Regelung der Blindleistung und Spannung und ii) das Umrichterverhalten bei Spannungseinbrüchen aufgrund von Netzkurzschlüssen [engl. fault ride through (FRT)] im seeseitigen Wechselspannungsnetz. Hierfür werden Blindleistungsoptimierungsverfahren präsentiert, die für die Anwendung in Wechselstromnetzen mit einem netzbildenden Umrichter und weiteren netzsynchronen Umrichtern geeignet sind. Die vorgeschlagene Blindleistung– und Spannungsregelungsmethode verringert die Energieverluste im seeseitigen Netz und erhöht damit die Energieausbeute des Systems. Häufig werden verschiedene Windparks zu Clustern zusammengeschlossen, die mehrschichtige Regelungsansätze fordern. Hierfür wird ein weiteres Verfahren vorgeschlagen, das ähnliche Kommunikationsanforderungen wie herkömmliche Betriebsverfahren aufweist, jedoch geringere Verluste verursacht. Die Arbeit untersucht ferner ein dynamisches Regelungsverfahren für den seeseitigen HGÜ–Umrichter. Dabei wird speziell das Verhalten während unsymmetrischer Kurzschlüsse im seeseitigen Netz berücksichtigt. Darüber hinaus wird der Betrieb des modularen Mehrpunktumrichters (engl. MMC) für diese Anwendung analysiert. Bezüglich des Verhaltens netzsynchroner Umrichter während asymmetrischer Spannungseinbrüche im seeseitigen Netz werden weiterhin vier Verfahren untersucht. Diese zielen unter anderem auf die Verringerung von möglicher Übermodulation der Umrichter und Überspannungen im seeseitigen Netz ab.
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Linne, Eva Marie. « Part-load operation of mini cogeneration plants in medium voltage grids ». Universitätsbibliothek Chemnitz, 2005. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200501638.
Texte intégralRésumé :
This paper deals with control strategies for mini cogeneration plants (short: CGP) in medium voltage grids. The aim of the paper is to explain and to minimize the trade-off between highest electrical efficiency in electrical energy production and the needs of energy reserve caused by uncertain load estimation. In general, high energy reserve means low electrical efficiency in electricity production. But fuel cells offer a high electrical efficiency in a relatively wide control range.